katie_definition(-DQT_NO_NAS)
endif()
-if(NOT WITH_PNG OR NOT PNG_FOUND)
+if(NOT WITH_PNG)
katie_definition(-DQT_NO_IMAGEFORMAT_PNG)
endif()
--- /dev/null
+Libpng 1.6.17 - March 26, 2015
+
+This is a public release of libpng, intended for use in production codes.
+
+Files available for download:
+
+Source files with LF line endings (for Unix/Linux) and with a
+"configure" script
+
+ libpng-1.6.17.tar.xz (LZMA-compressed, recommended)
+ libpng-1.6.17.tar.gz
+
+Source files with CRLF line endings (for Windows), without the
+"configure" script
+
+ lpng1617.7z (LZMA-compressed, recommended)
+ lpng1617.zip
+
+Other information:
+
+ libpng-1.6.17-README.txt
+ libpng-1.6.17-LICENSE.txt
+ libpng-1.6.17-*.asc (armored detached GPG signatures)
+
+Changes since the last public release (1.6.16):
+
+ Removed duplicate PNG_SAFE_LIMITS_SUPPORTED handling from pngconf.h
+ Corrected the width limit calculation in png_check_IHDR().
+ Removed user limits from pngfix. Also pass NULL pointers to
+ png_read_row to skip the unnecessary row de-interlace stuff.
+ Added testing of png_set_packing() to pngvalid.c
+ Regenerated configure scripts in the *.tar distributions with libtool-2.4.4
+ Implement previously untested cases of libpng transforms in pngvalid.c
+ Fixed byte order in 2-byte filler, in png_do_read_filler().
+ Made the check for out-of-range values in png_set_tRNS() detect
+ values that are exactly 2^bit_depth, and work on 16-bit platforms.
+ Merged some parts of libpng-1.6.17beta01 and libpng-1.7.0beta47.
+ Added #ifndef __COVERITY__ where needed in png.c, pngrutil.c and
+ pngset.c to avoid warnings about dead code.
+ Do not build png_product2() when it is unused.
+ Display user limits in the output from pngtest.
+ Eliminated the PNG_SAFE_LIMITS macro and restored the 1-million-column
+ and 1-million-row default limits in pnglibconf.dfa, that can be reset
+ by the user at build time or run time. This provides a more robust
+ defense against DOS and as-yet undiscovered overflows.
+ Added PNG_WRITE_CUSTOMIZE_COMPRESSION_SUPPORTED macro, on by default.
+ Allow user to call png_get_IHDR() with NULL arguments (Reuben Hawkins).
+ Rebuilt configure scripts with automake-1.15 and libtool-2.4.6
+ Moved png_set_filter() prototype into a PNG_WRITE_SUPPORTED block
+ of png.h.
+ Avoid runtime checks when converting integer to png_byte with
+ Visual Studio (Sergey Kosarevsky)
+ Removed some comments that the configure script did not handle
+ properly from scripts/pnglibconf.dfa and pnglibconf.h.prebuilt.
+ Free the unknown_chunks structure even when it contains no data.
+ Updated CMakeLists.txt to add OSX framework, change YES/NO to ON/OFF
+ for consistency, and remove some useless tests (Alexey Petruchik).
+ Remove pnglibconf.h, pnglibconf.c, pnglibconf.pre, pnglibconf.dfn,
+ and pnglibconf.out instead of pnglibconf.* in "make clean" (Cosmin).
+ Fixed simplified 8-bit-linear to sRGB alpha. The calculated alpha
+ value was wrong. It's not clear if this affected the final stored
+ value; in the obvious code path the upper and lower 8-bits of the
+ alpha value were identical and the alpha was truncated to 8-bits
+ rather than dividing by 257 (John Bowler).
+
+Send comments/corrections/commendations to png-mng-implement at lists.sf.net
+(subscription required; visit
+https://lists.sourceforge.net/lists/listinfo/png-mng-implement
+to subscribe)
+or to glennrp at users.sourceforge.net
+
+Glenn R-P
--- /dev/null
+
+CHANGES - changes for libpng
+
+Version 0.2
+ added reader into png.h
+ fixed small problems in stub file
+
+Version 0.3
+ added pull reader
+ split up pngwrite.c to several files
+ added pnglib.txt
+ added example.c
+ cleaned up writer, adding a few new transformations
+ fixed some bugs in writer
+ interfaced with zlib 0.5
+ added K&R support
+ added check for 64 KB blocks for 16-bit machines
+
+Version 0.4
+ cleaned up code and commented code
+ simplified time handling into png_time
+ created png_color_16 and png_color_8 to handle color needs
+ cleaned up color type defines
+ fixed various bugs
+ made various names more consistent
+ interfaced with zlib 0.71
+ cleaned up zTXt reader and writer (using zlib's Reset functions)
+ split transformations into pngrtran.c and pngwtran.c
+
+Version 0.5
+ interfaced with zlib 0.8
+ fixed many reading and writing bugs
+ saved using 3 spaces instead of tabs
+
+Version 0.6
+ added png_large_malloc() and png_large_free()
+ added png_size_t
+ cleaned up some compiler warnings
+ added png_start_read_image()
+
+Version 0.7
+ cleaned up lots of bugs
+ finished dithering and other stuff
+ added test program
+ changed name from pnglib to libpng
+
+Version 0.71 [June, 1995]
+ changed pngtest.png for zlib 0.93
+ fixed error in libpng.txt and example.c
+
+Version 0.8
+ cleaned up some bugs
+ added png_set_filler()
+ split up pngstub.c into pngmem.c, pngio.c, and pngerror.c
+ added #define's to remove unwanted code
+ moved png_info_init() to png.c
+ added old_size into png_realloc()
+ added functions to manually set filtering and compression info
+ changed compression parameters based on image type
+ optimized filter selection code
+ added version info
+ changed external functions passing floats to doubles (k&r problems?)
+ put all the configurable stuff in pngconf.h
+ enabled png_set_shift to work with paletted images on read
+ added png_read_update_info() - updates info structure with transformations
+
+Version 0.81 [August, 1995]
+ incorporated Tim Wegner's medium model code (thanks, Tim)
+
+Version 0.82 [September, 1995]
+ [unspecified changes]
+
+Version 0.85 [December, 1995]
+ added more medium model code (almost everything's a far)
+ added i/o, error, and memory callback functions
+ fixed some bugs (16-bit, 4-bit interlaced, etc.)
+ added first run progressive reader (barely tested)
+
+Version 0.86 [January, 1996]
+ fixed bugs
+ improved documentation
+
+Version 0.87 [January, 1996]
+ fixed medium model bugs
+ fixed other bugs introduced in 0.85 and 0.86
+ added some minor documentation
+
+Version 0.88 [January, 1996]
+ fixed progressive bugs
+ replaced tabs with spaces
+ cleaned up documentation
+ added callbacks for read/write and warning/error functions
+
+Version 0.89 [July, 1996]
+ Added new initialization API to make libpng work better with shared libs
+ we now have png_create_read_struct(), png_create_write_struct(),
+ png_create_info_struct(), png_destroy_read_struct(), and
+ png_destroy_write_struct() instead of the separate calls to
+ malloc and png_read_init(), png_info_init(), and png_write_init()
+ Changed warning/error callback functions to fix bug - this means you
+ should use the new initialization API if you were using the old
+ png_set_message_fn() calls, and that the old API no longer exists
+ so that people are aware that they need to change their code
+ Changed filter selection API to allow selection of multiple filters
+ since it didn't work in previous versions of libpng anyways
+ Optimized filter selection code
+ Fixed png_set_background() to allow using an arbitrary RGB color for
+ paletted images
+ Fixed gamma and background correction for paletted images, so
+ png_correct_palette is not needed unless you are correcting an
+ external palette (you will need to #define PNG_CORRECT_PALETTE_SUPPORTED
+ in pngconf.h) - if nobody uses this, it may disappear in the future.
+ Fixed bug with Borland 64K memory allocation (Alexander Lehmann)
+ Fixed bug in interlace handling (Smarasderagd, I think)
+ Added more error checking for writing and image to reduce invalid files
+ Separated read and write functions so that they won't both be linked
+ into a binary when only reading or writing functionality is used
+ New pngtest image also has interlacing and zTXt
+ Updated documentation to reflect new API
+
+Version 0.90 [January, 1997]
+ Made CRC errors/warnings on critical and ancillary chunks configurable
+ libpng will use the zlib CRC routines by (compile-time) default
+ Changed DOS small/medium model memory support - needs zlib 1.04 (Tim Wegner)
+ Added external C++ wrapper statements to png.h (Gilles Dauphin)
+ Allow PNG file to be read when some or all of file signature has already
+ been read from the beginning of the stream. ****This affects the size
+ of info_struct and invalidates all programs that use a shared libpng****
+ Fixed png_filler() declarations
+ Fixed? background color conversions
+ Fixed order of error function pointers to match documentation
+ Current chunk name is now available in png_struct to reduce the number
+ of nearly identical error messages (will simplify multi-lingual
+ support when available)
+ Try to get ready for unknown-chunk callback functions:
+ - previously read critical chunks are flagged, so the chunk handling
+ routines can determine if the chunk is in the right place
+ - all chunk handling routines have the same prototypes, so we will
+ be able to handle all chunks via a callback mechanism
+ Try to fix Linux "setjmp" buffer size problems
+ Removed png_large_malloc, png_large_free, and png_realloc functions.
+
+Version 0.95 [March, 1997]
+ Fixed bug in pngwutil.c allocating "up_row" twice and "avg_row" never
+ Fixed bug in PNG file signature compares when start != 0
+ Changed parameter type of png_set_filler(...filler...) from png_byte
+ to png_uint_32
+ Added test for MACOS to ensure that both math.h and fp.h are not #included
+ Added macros for libpng to be compiled as a Windows DLL (Andreas Kupries)
+ Added "packswap" transformation, which changes the endianness of
+ packed-pixel bytes (Kevin Bracey)
+ Added "strip_alpha" transformation, which removes the alpha channel of
+ input images without using it (not necessarily a good idea)
+ Added "swap_alpha" transformation, which puts the alpha channel in front
+ of the color bytes instead of after
+ Removed all implicit variable tests which assume NULL == 0 (I think)
+ Changed several variables to "png_size_t" to show 16/32-bit limitations
+ Added new pCAL chunk read/write support
+ Added experimental filter selection weighting (Greg Roelofs)
+ Removed old png_set_rgbx() and png_set_xrgb() functions that have been
+ obsolete for about 2 years now (use png_set_filler() instead)
+ Added macros to read 16- and 32-bit ints directly from buffer, to be
+ used only on those systems that support it (namely PowerPC and 680x0)
+ With some testing, this may become the default for MACOS/PPC systems.
+ Only calculate CRC on data if we are going to use it
+ Added macros for zTXt compression type PNG_zTXt_COMPRESSION_???
+ Added macros for simple libpng debugging output selectable at compile time
+ Removed PNG_READ_END_MODE in progressive reader (Smarasderagd)
+ More description of info_struct in libpng.txt and png.h
+ More instructions in example.c
+ More chunk types tested in pngtest.c
+ Renamed pngrcb.c to pngset.c, and all png_read_<chunk> functions to be
+ png_set_<chunk>. We now have corresponding png_get_<chunk>
+ functions in pngget.c to get information in info_ptr. This isolates
+ the application from the internal organization of png_info_struct
+ (good for shared library implementations).
+
+Version 0.96 [May, 1997]
+ Fixed serious bug with < 8bpp images introduced in 0.95
+ Fixed 256-color transparency bug (Greg Roelofs)
+ Fixed up documentation (Greg Roelofs, Laszlo Nyul)
+ Fixed "error" in pngconf.h for Linux setjmp() behavior
+ Fixed DOS medium model support (Tim Wegner)
+ Fixed png_check_keyword() for case with error in static string text
+ Added read of CRC after IEND chunk for embedded PNGs (Laszlo Nyul)
+ Added typecasts to quiet compiler errors
+ Added more debugging info
+
+Version 0.97 [January, 1998]
+ Removed PNG_USE_OWN_CRC capability
+ Relocated png_set_crc_action from pngrutil.c to pngrtran.c
+ Fixed typecasts of "new_key", etc. (Andreas Dilger)
+ Added RFC 1152 [sic] date support
+ Fixed bug in gamma handling of 4-bit grayscale
+ Added 2-bit grayscale gamma handling (Glenn R-P)
+ Added more typecasts. 65536L becomes (png_uint_32)65536L, etc. (Glenn R-P)
+ Minor corrections in libpng.txt
+ Added simple sRGB support (Glenn R-P)
+ Easier conditional compiling, e.g.,
+ define PNG_READ/WRITE_NOT_FULLY_SUPPORTED;
+ all configurable options can be selected from command-line instead
+ of having to edit pngconf.h (Glenn R-P)
+ Fixed memory leak in pngwrite.c (free info_ptr->text) (Glenn R-P)
+ Added more conditions for png_do_background, to avoid changing
+ black pixels to background when a background is supplied and
+ no pixels are transparent
+ Repaired PNG_NO_STDIO behavior
+ Tested NODIV support and made it default behavior (Greg Roelofs)
+ Added "-m" option and PNGTEST_DEBUG_MEMORY to pngtest (John Bowler)
+ Regularized version numbering scheme and bumped shared-library major
+ version number to 2 to avoid problems with libpng 0.89 apps
+ (Greg Roelofs)
+
+Version 0.98 [January, 1998]
+ Cleaned up some typos in libpng.txt and in code documentation
+ Fixed memory leaks in pCAL chunk processing (Glenn R-P and John Bowler)
+ Cosmetic change "display_gamma" to "screen_gamma" in pngrtran.c
+ Changed recommendation about file_gamma for PC images to .51 from .45,
+ in example.c and libpng.txt, added comments to distinguish between
+ screen_gamma, viewing_gamma, and display_gamma.
+ Changed all references to RFC1152 to read RFC1123 and changed the
+ PNG_TIME_RFC1152_SUPPORTED macro to PNG_TIME_RFC1123_SUPPORTED
+ Added png_invert_alpha capability (Glenn R-P -- suggestion by Jon Vincent)
+ Changed srgb_intent from png_byte to int to avoid compiler bugs
+
+Version 0.99 [January 30, 1998]
+ Free info_ptr->text instead of end_info_ptr->text in pngread.c (John Bowler)
+ Fixed a longstanding "packswap" bug in pngtrans.c
+ Fixed some inconsistencies in pngconf.h that prevented compiling with
+ PNG_READ_GAMMA_SUPPORTED and PNG_READ_hIST_SUPPORTED undefined
+ Fixed some typos and made other minor rearrangement of libpng.txt (Andreas)
+ Changed recommendation about file_gamma for PC images to .50 from .51 in
+ example.c and libpng.txt, and changed file_gamma for sRGB images to .45
+ Added a number of functions to access information from the png structure
+ png_get_image_height(), etc. (Glenn R-P, suggestion by Brad Pettit)
+ Added TARGET_MACOS similar to zlib-1.0.8
+ Define PNG_ALWAYS_EXTERN when __MWERKS__ && WIN32 are defined
+ Added type casting to all png_malloc() function calls
+
+Version 0.99a [January 31, 1998]
+ Added type casts and parentheses to all returns that return a value.(Tim W.)
+
+Version 0.99b [February 4, 1998]
+ Added type cast png_uint_32 on malloc function calls where needed.
+ Changed type of num_hist from png_uint_32 to int (same as num_palette).
+ Added checks for rowbytes overflow, in case png_size_t is less than 32 bits.
+ Renamed makefile.elf to makefile.lnx.
+
+Version 0.99c [February 7, 1998]
+ More type casting. Removed erroneous overflow test in pngmem.c.
+ Added png_buffered_memcpy() and png_buffered_memset(), apply them to rowbytes.
+ Added UNIX manual pages libpng.3 (incorporating libpng.txt) and png.5.
+
+Version 0.99d [February 11, 1998]
+ Renamed "far_to_near()" "png_far_to_near()"
+ Revised libpng.3
+ Version 99c "buffered" operations didn't work as intended. Replaced them
+ with png_memcpy_check() and png_memset_check().
+ Added many "if (png_ptr == NULL) return" to quell compiler warnings about
+ unused png_ptr, mostly in pngget.c and pngset.c.
+ Check for overlength tRNS chunk present when indexed-color PLTE is read.
+ Cleaned up spelling errors in libpng.3/libpng.txt
+ Corrected a problem with png_get_tRNS() which returned undefined trans array
+
+Version 0.99e [February 28, 1998]
+ Corrected png_get_tRNS() again.
+ Add parentheses for easier reading of pngget.c, fixed "||" should be "&&".
+ Touched up example.c to make more of it compileable, although the entire
+ file still can't be compiled (Willem van Schaik)
+ Fixed a bug in png_do_shift() (Bryan Tsai)
+ Added a space in png.h prototype for png_write_chunk_start()
+ Replaced pngtest.png with one created with zlib 1.1.1
+ Changed pngtest to report PASS even when file size is different (Jean-loup G.)
+ Corrected some logic errors in png_do_invert_alpha() (Chris Patterson)
+
+Version 0.99f [March 5, 1998]
+ Corrected a bug in pngpread() introduced in version 99c (Kevin Bracey)
+ Moved makefiles into a "scripts" directory, and added INSTALL instruction file
+ Added makefile.os2 and pngos2.def (A. Zabolotny) and makefile.s2x (W. Sebok)
+ Added pointers to "note on libpng versions" in makefile.lnx and README
+ Added row callback feature when reading and writing nonprogressive rows
+ and added a test of this feature in pngtest.c
+ Added user transform callbacks, with test of the feature in pngtest.c
+
+Version 0.99g [March 6, 1998, morning]
+ Minor changes to pngtest.c to suppress compiler warnings.
+ Removed "beta" language from documentation.
+
+Version 0.99h [March 6, 1998, evening]
+ Minor changes to previous minor changes to pngtest.c
+ Changed PNG_READ_NOT_FULLY_SUPPORTED to PNG_READ_TRANSFORMS_NOT_SUPPORTED
+ and added PNG_PROGRESSIVE_READ_NOT_SUPPORTED macro
+ Added user transform capability
+
+Version 1.00 [March 7, 1998]
+ Changed several typedefs in pngrutil.c
+ Added makefile.wat (Pawel Mrochen), updated makefile.tc3 (Willem van Schaik)
+ Replaced "while(1)" with "for(;;)"
+ Added PNGARG() to prototypes in pngtest.c and removed some prototypes
+ Updated some of the makefiles (Tom Lane)
+ Changed some typedefs (s_start, etc.) in pngrutil.c
+ Fixed dimensions of "short_months" array in pngwrite.c
+ Replaced ansi2knr.c with the one from jpeg-v6
+
+Version 1.0.0 [March 8, 1998]
+ Changed name from 1.00 to 1.0.0 (Adam Costello)
+ Added smakefile.ppc (with SCOPTIONS.ppc) for Amiga PPC (Andreas Kleinert)
+
+Version 1.0.0a [March 9, 1998]
+ Fixed three bugs in pngrtran.c to make gamma+background handling consistent
+ (Greg Roelofs)
+ Changed format of the PNG_LIBPNG_VER integer to xyyzz instead of xyz
+ for major, minor, and bugfix releases. This is 10001. (Adam Costello,
+ Tom Lane)
+ Make months range from 1-12 in png_convert_to_rfc1123
+
+Version 1.0.0b [March 13, 1998]
+ Quieted compiler complaints about two empty "for" loops in pngrutil.c
+ Minor changes to makefile.s2x
+ Removed #ifdef/#endif around a png_free() in pngread.c
+
+Version 1.0.1 [March 14, 1998]
+ Changed makefile.s2x to reduce security risk of using a relative pathname
+ Fixed some typos in the documentation (Greg).
+ Fixed a problem with value of "channels" returned by png_read_update_info()
+
+Version 1.0.1a [April 21, 1998]
+ Optimized Paeth calculations by replacing abs() function calls with intrinsics
+ plus other loop optimizations. Improves avg decoding speed by about 20%.
+ Commented out i386istic "align" compiler flags in makefile.lnx.
+ Reduced the default warning level in some makefiles, to make them consistent.
+ Removed references to IJG and JPEG in the ansi2knr.c copyright statement.
+ Fixed a bug in png_do_strip_filler with XXRRGGBB => RRGGBB transformation.
+ Added grayscale and 16-bit capability to png_do_read_filler().
+ Fixed a bug in pngset.c, introduced in version 0.99c, that sets rowbytes
+ too large when writing an image with bit_depth < 8 (Bob Dellaca).
+ Corrected some bugs in the experimental weighted filtering heuristics.
+ Moved a misplaced pngrutil code block that truncates tRNS if it has more
+ than num_palette entries -- test was done before num_palette was defined.
+ Fixed a png_convert_to_rfc1123() bug that converts day 31 to 0 (Steve Eddins).
+ Changed compiler flags in makefile.wat for better optimization
+ (Pawel Mrochen).
+
+Version 1.0.1b [May 2, 1998]
+ Relocated png_do_gray_to_rgb() within png_do_read_transformations() (Greg).
+ Relocated the png_composite macros from pngrtran.c to png.h (Greg).
+ Added makefile.sco (contributed by Mike Hopkirk).
+ Fixed two bugs (missing definitions of "istop") introduced in libpng-1.0.1a.
+ Fixed a bug in pngrtran.c that would set channels=5 under some circumstances.
+ More work on the Paeth-filtering, achieving imperceptible speedup
+ (A Kleinert).
+ More work on loop optimization which may help when compiled with C++
+ compilers.
+ Added warnings when people try to use transforms they've defined out.
+ Collapsed 4 "i" and "c" loops into single "i" loops in pngrtran and pngwtran.
+ Revised paragraph about png_set_expand() in libpng.txt and libpng.3 (Greg)
+
+Version 1.0.1c [May 11, 1998]
+ Fixed a bug in pngrtran.c (introduced in libpng-1.0.1a) where the masks for
+ filler bytes should have been 0xff instead of 0xf.
+ Added max_pixel_depth=32 in pngrutil.c when using FILLER with palette images.
+ Moved PNG_WRITE_WEIGHTED_FILTER_SUPPORTED and PNG_WRITE_FLUSH_SUPPORTED
+ out of the PNG_WRITE_TRANSFORMS_NOT_SUPPORTED block of pngconf.h
+ Added "PNG_NO_WRITE_TRANSFORMS" etc., as alternatives for *_NOT_SUPPORTED,
+ for consistency, in pngconf.h
+ Added individual "ifndef PNG_NO_[CAPABILITY]" in pngconf.h to make it easier
+ to remove unwanted capabilities via the compile line
+ Made some corrections to grammar (which, it's) in documentation (Greg).
+ Corrected example.c, use of row_pointers in png_write_image().
+
+Version 1.0.1d [May 24, 1998]
+ Corrected several statements that used side effects illegally in pngrutil.c
+ and pngtrans.c, that were introduced in version 1.0.1b
+ Revised png_read_rows() to avoid repeated if-testing for NULL (A Kleinert)
+ More corrections to example.c, use of row_pointers in png_write_image()
+ and png_read_rows().
+ Added pngdll.mak and pngdef.pas to scripts directory, contributed by
+ Bob Dellaca, to make a png32bd.dll with Borland C++ 4.5
+ Fixed error in example.c with png_set_text: num_text is 3, not 2 (Guido V.)
+ Changed several loops from count-down to count-up, for consistency.
+
+Version 1.0.1e [June 6, 1998]
+ Revised libpng.txt and libpng.3 description of png_set_read|write_fn(), and
+ added warnings when people try to set png_read_fn and png_write_fn in
+ the same structure.
+ Added a test such that png_do_gamma will be done when num_trans==0
+ for truecolor images that have defined a background. This corrects an
+ error that was introduced in libpng-0.90 that can cause gamma processing
+ to be skipped.
+ Added tests in png.h to include "trans" and "trans_values" in structures
+ when PNG_READ_BACKGROUND_SUPPORTED or PNG_READ_EXPAND_SUPPORTED is defined.
+ Add png_free(png_ptr->time_buffer) in png_destroy_read_struct()
+ Moved png_convert_to_rfc_1123() from pngwrite.c to png.c
+ Added capability for user-provided malloc_fn() and free_fn() functions,
+ and revised pngtest.c to demonstrate their use, replacing the
+ PNGTEST_DEBUG_MEM feature.
+ Added makefile.w32, for Microsoft C++ 4.0 and later (Tim Wegner).
+
+Version 1.0.2 [June 14, 1998]
+ Fixed two bugs in makefile.bor .
+
+Version 1.0.2a [December 30, 1998]
+ Replaced and extended code that was removed from png_set_filler() in 1.0.1a.
+ Fixed a bug in png_do_filler() that made it fail to write filler bytes in
+ the left-most pixel of each row (Kevin Bracey).
+ Changed "static pngcharp tIME_string" to "static char tIME_string[30]"
+ in pngtest.c (Duncan Simpson).
+ Fixed a bug in pngtest.c that caused pngtest to try to write a tIME chunk
+ even when no tIME chunk was present in the source file.
+ Fixed a problem in pngrutil.c: gray_to_rgb didn't always work with 16-bit.
+ Fixed a problem in png_read_push_finish_row(), which would not skip some
+ passes that it should skip, for images that are less than 3 pixels high.
+ Interchanged the order of calls to png_do_swap() and png_do_shift()
+ in pngwtran.c (John Cromer).
+ Added #ifdef PNG_DEBUG/#endif surrounding use of PNG_DEBUG in png.h .
+ Changed "bad adaptive filter type" from error to warning in pngrutil.c .
+ Fixed a documentation error about default filtering with 8-bit indexed-color.
+ Separated the PNG_NO_STDIO macro into PNG_NO_STDIO and PNG_NO_CONSOLE_IO
+ (L. Peter Deutsch).
+ Added png_set_rgb_to_gray() and png_get_rgb_to_gray_status() functions.
+ Added png_get_copyright() and png_get_header_version() functions.
+ Revised comments on png_set_progressive_read_fn() in libpng.txt and example.c
+ Added information about debugging in libpng.txt and libpng.3 .
+ Changed "ln -sf" to "ln -s -f" in makefile.s2x, makefile.lnx, and
+ makefile.sco.
+ Removed lines after Dynamic Dependencies" in makefile.aco .
+ Revised makefile.dec to make a shared library (Jeremie Petit).
+ Removed trailing blanks from all files.
+
+Version 1.0.2a [January 6, 1999]
+ Removed misplaced #endif and #ifdef PNG_NO_EXTERN near the end of png.h
+ Added "if" tests to silence complaints about unused png_ptr in png.h and png.c
+ Changed "check_if_png" function in example.c to return true (nonzero) if PNG.
+ Changed libpng.txt to demonstrate png_sig_cmp() instead of png_check_sig()
+ which is obsolete.
+
+Version 1.0.3 [January 14, 1999]
+ Added makefile.hux, for Hewlett Packard HPUX 10.20 and 11.00 (Jim Rice)
+ Added a statement of Y2K compliance in png.h, libpng.3, and Y2KINFO.
+
+Version 1.0.3a [August 12, 1999]
+ Added check for PNG_READ_INTERLACE_SUPPORTED in pngread.c; issue a warning
+ if an attempt is made to read an interlaced image when it's not supported.
+ Added check if png_ptr->trans is defined before freeing it in pngread.c
+ Modified the Y2K statement to include versions back to version 0.71
+ Fixed a bug in the check for valid IHDR bit_depth/color_types in pngrutil.c
+ Modified makefile.wat (added -zp8 flag, ".symbolic", changed some comments)
+ Replaced leading blanks with tab characters in makefile.hux
+ Changed "dworkin.wustl.edu" to "ccrc.wustl.edu" in various documents.
+ Changed (float)red and (float)green to (double)red, (double)green
+ in png_set_rgb_to_gray() to avoid "promotion" problems in AIX.
+ Fixed a bug in pngconf.h that omitted <stdio.h> when PNG_DEBUG==0 (K Bracey).
+ Reformatted libpng.3 and libpngpf.3 with proper fonts (script by J. vanZandt).
+ Updated documentation to refer to the PNG-1.2 specification.
+ Removed ansi2knr.c and left pointers to the latest source for ansi2knr.c
+ in makefile.knr, INSTALL, and README (L. Peter Deutsch)
+ Fixed bugs in calculation of the length of rowbytes when adding alpha
+ channels to 16-bit images, in pngrtran.c (Chris Nokleberg)
+ Added function png_set_user_transform_info() to store user_transform_ptr,
+ user_depth, and user_channels into the png_struct, and a function
+ png_get_user_transform_ptr() to retrieve the pointer (Chris Nokleberg)
+ Added function png_set_empty_plte_permitted() to make libpng useable
+ in MNG applications.
+ Corrected the typedef for png_free_ptr in png.h (Jesse Jones).
+ Correct gamma with srgb is 45455 instead of 45000 in pngrutil.c, to be
+ consistent with PNG-1.2, and allow variance of 500 before complaining.
+ Added assembler code contributed by Intel in file pngvcrd.c and modified
+ makefile.w32 to use it (Nirav Chhatrapati, INTEL Corporation,
+ Gilles Vollant)
+ Changed "ln -s -f" to "ln -f -s" in the makefiles to make Solaris happy.
+ Added some aliases for png_set_expand() in pngrtran.c, namely
+ png_set_expand_PLTE(), png_set_expand_depth(), and png_set_expand_tRNS()
+ (Greg Roelofs, in "PNG: The Definitive Guide").
+ Added makefile.beo for BEOS on X86, contributed by Sander Stok.
+
+Version 1.0.3b [August 26, 1999]
+ Replaced 2147483647L several places with PNG_MAX_UINT macro, defined in png.h
+ Changed leading blanks to tabs in all makefiles.
+ Define PNG_USE_PNGVCRD in makefile.w32, to get MMX assembler code.
+ Made alternate versions of png_set_expand() in pngrtran.c, namely
+ png_set_gray_1_2_4_to_8, png_set_palette_to_rgb, and png_set_tRNS_to_alpha
+ (Greg Roelofs, in "PNG: The Definitive Guide"). Deleted the 1.0.3a aliases.
+ Relocated start of 'extern "C"' block in png.h so it doesn't include pngconf.h
+ Revised calculation of num_blocks in pngmem.c to avoid a potentially
+ negative shift distance, whose results are undefined in the C language.
+ Added a check in pngset.c to prevent writing multiple tIME chunks.
+ Added a check in pngwrite.c to detect invalid small window_bits sizes.
+
+Version 1.0.3d [September 4, 1999]
+ Fixed type casting of igamma in pngrutil.c
+ Added new png_expand functions to scripts/pngdef.pas and pngos2.def
+ Added a demo read_user_transform_fn that examines the row filters in pngtest.c
+
+Version 1.0.4 [September 24, 1999]
+ Define PNG_ALWAYS_EXTERN in pngconf.h if __STDC__ is defined
+ Delete #define PNG_INTERNAL and include "png.h" from pngasmrd.h
+ Made several minor corrections to pngtest.c
+ Renamed the makefiles with longer but more user friendly extensions.
+ Copied the PNG copyright and license to a separate LICENSE file.
+ Revised documentation, png.h, and example.c to remove reference to
+ "viewing_gamma" which no longer appears in the PNG specification.
+ Revised pngvcrd.c to use MMX code for interlacing only on the final pass.
+ Updated pngvcrd.c to use the faster C filter algorithms from libpng-1.0.1a
+ Split makefile.win32vc into two versions, makefile.vcawin32 (uses MMX
+ assembler code) and makefile.vcwin32 (doesn't).
+ Added a CPU timing report to pngtest.c (enabled by defining PNGTEST_TIMING)
+ Added a copy of pngnow.png to the distribution.
+
+Version 1.0.4a [September 25, 1999]
+ Increase max_pixel_depth in pngrutil.c if a user transform needs it.
+ Changed several division operations to right-shifts in pngvcrd.c
+
+Version 1.0.4b [September 30, 1999]
+ Added parentheses in line 3732 of pngvcrd.c
+ Added a comment in makefile.linux warning about buggy -O3 in pgcc 2.95.1
+
+Version 1.0.4c [October 1, 1999]
+ Added a "png_check_version" function in png.c and pngtest.c that will generate
+ a helpful compiler error if an old png.h is found in the search path.
+ Changed type of png_user_transform_depth|channels from int to png_byte.
+
+Version 1.0.4d [October 6, 1999]
+ Changed 0.45 to 0.45455 in png_set_sRGB()
+ Removed unused PLTE entries from pngnow.png
+ Re-enabled some parts of pngvcrd.c (png_combine_row) that work properly.
+
+Version 1.0.4e [October 10, 1999]
+ Fixed sign error in pngvcrd.c (Greg Roelofs)
+ Replaced some instances of memcpy with simple assignments in pngvcrd (GR-P)
+
+Version 1.0.4f [October 15, 1999]
+ Surrounded example.c code with #if 0 .. #endif to prevent people from
+ inadvertently trying to compile it.
+ Changed png_get_header_version() from a function to a macro in png.h
+ Added type casting mostly in pngrtran.c and pngwtran.c
+ Removed some pointless "ptr = NULL" in pngmem.c
+ Added a "contrib" directory containing the source code from Greg's book.
+
+Version 1.0.5 [October 15, 1999]
+ Minor editing of the INSTALL and README files.
+
+Version 1.0.5a [October 23, 1999]
+ Added contrib/pngsuite and contrib/pngminus (Willem van Schaik)
+ Fixed a typo in the png_set_sRGB() function call in example.c (Jan Nijtmans)
+ Further optimization and bugfix of pngvcrd.c
+ Revised pngset.c so that it does not allocate or free memory in the user's
+ text_ptr structure. Instead, it makes its own copy.
+ Created separate write_end_info_struct in pngtest.c for a more severe test.
+ Added code in pngwrite.c to free info_ptr->text[i].key to stop a memory leak.
+
+Version 1.0.5b [November 23, 1999]
+ Moved PNG_FLAG_HAVE_CHUNK_HEADER, PNG_FLAG_BACKGROUND_IS_GRAY and
+ PNG_FLAG_WROTE_tIME from flags to mode.
+ Added png_write_info_before_PLTE() function.
+ Fixed some typecasting in contrib/gregbook/*.c
+ Updated scripts/makevms.com and added makevms.com to contrib/gregbook
+ and contrib/pngminus (Martin Zinser)
+
+Version 1.0.5c [November 26, 1999]
+ Moved png_get_header_version from png.h to png.c, to accommodate ansi2knr.
+ Removed all global arrays (according to PNG_NO_GLOBAL_ARRAYS macro), to
+ accommodate making DLL's: Moved usr_png_ver from global variable to function
+ png_get_header_ver() in png.c. Moved png_sig to png_sig_bytes in png.c and
+ eliminated use of png_sig in pngwutil.c. Moved the various png_CHNK arrays
+ into pngtypes.h. Eliminated use of global png_pass arrays. Declared the
+ png_CHNK and png_pass arrays to be "const". Made the global arrays
+ available to applications (although none are used in libpng itself) when
+ PNG_NO_GLOBAL_ARRAYS is not defined or when PNG_GLOBAL_ARRAYS is defined.
+ Removed some extraneous "-I" from contrib/pngminus/makefile.std
+ Changed the PNG_sRGB_INTENT macros in png.h to be consistent with PNG-1.2.
+ Change PNG_SRGB_INTENT to PNG_sRGB_INTENT in libpng.txt and libpng.3
+
+Version 1.0.5d [November 29, 1999]
+ Add type cast (png_const_charp) two places in png.c
+ Eliminated pngtypes.h; use macros instead to declare PNG_CHNK arrays.
+ Renamed "PNG_GLOBAL_ARRAYS" to "PNG_USE_GLOBAL_ARRAYS" and made available
+ to applications a macro "PNG_USE_LOCAL_ARRAYS".
+ comment out (with #ifdef) all the new declarations when
+ PNG_USE_GLOBAL_ARRAYS is defined.
+ Added PNG_EXPORT_VAR macro to accommodate making DLL's.
+
+Version 1.0.5e [November 30, 1999]
+ Added iCCP, iTXt, and sPLT support; added "lang" member to the png_text
+ structure; refactored the inflate/deflate support to make adding new chunks
+ with trailing compressed parts easier in the future, and added new functions
+ png_free_iCCP, png_free_pCAL, png_free_sPLT, png_free_text, png_get_iCCP,
+ png_get_spalettes, png_set_iCCP, png_set_spalettes (Eric S. Raymond).
+ NOTE: Applications that write text chunks MUST define png_text->lang
+ before calling png_set_text(). It must be set to NULL if you want to
+ write tEXt or zTXt chunks. If you want your application to be able to
+ run with older versions of libpng, use
+
+ #ifdef PNG_iTXt_SUPPORTED
+ png_text[i].lang = NULL;
+ #endif
+
+ Changed png_get_oFFs() and png_set_oFFs() to use signed rather than unsigned
+ offsets (Eric S. Raymond).
+ Combined PNG_READ_cHNK_SUPPORTED and PNG_WRITE_cHNK_SUPPORTED macros into
+ PNG_cHNK_SUPPORTED and combined the three types of PNG_text_SUPPORTED
+ macros, leaving the separate macros also available.
+ Removed comments on #endifs at the end of many short, non-nested #if-blocks.
+
+Version 1.0.5f [December 6, 1999]
+ Changed makefile.solaris to issue a warning about potential problems when
+ the ucb "ld" is in the path ahead of the ccs "ld".
+ Removed "- [date]" from the "synopsis" line in libpng.3 and libpngpf.3.
+ Added sCAL chunk support (Eric S. Raymond).
+
+Version 1.0.5g [December 7, 1999]
+ Fixed "png_free_spallettes" typo in png.h
+ Added code to handle new chunks in pngpread.c
+ Moved PNG_CHNK string macro definitions outside of PNG_NO_EXTERN block
+ Added "translated_key" to png_text structure and png_write_iTXt().
+ Added code in pngwrite.c to work around a newly discovered zlib bug.
+
+Version 1.0.5h [December 10, 1999]
+ NOTE: regarding the note for version 1.0.5e, the following must also
+ be included in your code:
+ png_text[i].translated_key = NULL;
+ Unknown chunk handling is now supported.
+ Option to eliminate all floating point support was added. Some new
+ fixed-point functions such as png_set_gAMA_fixed() were added.
+ Expanded tabs and removed trailing blanks in source files.
+
+Version 1.0.5i [December 13, 1999]
+ Added some type casts to silence compiler warnings.
+ Renamed "png_free_spalette" to "png_free_spalettes" for consistency.
+ Removed leading blanks from a #define in pngvcrd.c
+ Added some parameters to the new png_set_keep_unknown_chunks() function.
+ Added a test for up->location != 0 in the first instance of writing
+ unknown chunks in pngwrite.c
+ Changed "num" to "i" in png_free_spalettes() and png_free_unknowns() to
+ prevent recursion.
+ Added png_free_hIST() function.
+ Various patches to fix bugs in the sCAL and integer cHRM processing,
+ and to add some convenience macros for use with sCAL.
+
+Version 1.0.5j [December 21, 1999]
+ Changed "unit" parameter of png_write_sCAL from png_byte to int, to work
+ around buggy compilers.
+ Added new type "png_fixed_point" for integers that hold float*100000 values
+ Restored backward compatibility of tEXt/zTXt chunk processing:
+ Restored the first four members of png_text to the same order as v.1.0.5d.
+ Added members "lang_key" and "itxt_length" to png_text struct. Set
+ text_length=0 when "text" contains iTXt data. Use the "compression"
+ member to distinguish among tEXt/zTXt/iTXt types. Added
+ PNG_ITXT_COMPRESSION_NONE (1) and PNG_ITXT_COMPRESSION_zTXt(2) macros.
+ The "Note" above, about backward incompatibility of libpng-1.0.5e, no
+ longer applies.
+ Fixed png_read|write_iTXt() to read|write parameters in the right order,
+ and to write the iTXt chunk after IDAT if it appears in the end_ptr.
+ Added pnggccrd.c, version of pngvcrd.c Intel assembler for gcc (Greg Roelofs)
+ Reversed the order of trying to write floating-point and fixed-point gAMA.
+
+Version 1.0.5k [December 27, 1999]
+ Added many parentheses, e.g., "if (a && b & c)" becomes "if (a && (b & c))"
+ Added png_handle_as_unknown() function (Glenn)
+ Added png_free_chunk_list() function and chunk_list and num_chunk_list members
+ of png_ptr.
+ Eliminated erroneous warnings about multiple sPLT chunks and sPLT-after-PLTE.
+ Fixed a libpng-1.0.5h bug in pngrutil.c that was issuing erroneous warnings
+ about ignoring incorrect gAMA with sRGB (gAMA was in fact not ignored)
+ Added png_free_tRNS(); png_set_tRNS() now malloc's its own trans array (ESR).
+ Define png_get_int_32 when oFFs chunk is supported as well as when pCAL is.
+ Changed type of proflen from png_int_32 to png_uint_32 in png_get_iCCP().
+
+Version 1.0.5l [January 1, 2000]
+ Added functions png_set_read_user_chunk_fn() and png_get_user_chunk_ptr()
+ for setting a callback function to handle unknown chunks and for
+ retrieving the associated user pointer (Glenn).
+
+Version 1.0.5m [January 7, 2000]
+ Added high-level functions png_read_png(), png_write_png(), png_free_pixels().
+
+Version 1.0.5n [January 9, 2000]
+ Added png_free_PLTE() function, and modified png_set_PLTE() to malloc its
+ own memory for info_ptr->palette. This makes it safe for the calling
+ application to free its copy of the palette any time after it calls
+ png_set_PLTE().
+
+Version 1.0.5o [January 20, 2000]
+ Cosmetic changes only (removed some trailing blanks and TABs)
+
+Version 1.0.5p [January 31, 2000]
+ Renamed pngdll.mak to makefile.bd32
+ Cosmetic changes in pngtest.c
+
+Version 1.0.5q [February 5, 2000]
+ Relocated the makefile.solaris warning about PATH problems.
+ Fixed pngvcrd.c bug by pushing/popping registers in mmxsupport (Bruce Oberg)
+ Revised makefile.gcmmx
+ Added PNG_SETJMP_SUPPORTED, PNG_SETJMP_NOT_SUPPORTED, and PNG_ABORT() macros
+
+Version 1.0.5r [February 7, 2000]
+ Removed superfluous prototype for png_get_itxt from png.h
+ Fixed a bug in pngrtran.c that improperly expanded the background color.
+ Return *num_text=0 from png_get_text() when appropriate, and fix documentation
+ of png_get_text() in libpng.txt/libpng.3.
+
+Version 1.0.5s [February 18, 2000]
+ Added "png_jmp_env()" macro to pngconf.h, to help people migrate to the
+ new error handler that's planned for the next libpng release, and changed
+ example.c, pngtest.c, and contrib programs to use this macro.
+ Revised some of the DLL-export macros in pngconf.h (Greg Roelofs)
+ Fixed a bug in png_read_png() that caused it to fail to expand some images
+ that it should have expanded.
+ Fixed some mistakes in the unused and undocumented INCH_CONVERSIONS functions
+ in pngget.c
+ Changed the allocation of palette, history, and trans arrays back to
+ the version 1.0.5 method (linking instead of copying) which restores
+ backward compatibility with version 1.0.5. Added some remarks about
+ that in example.c. Added "free_me" member to info_ptr and png_ptr
+ and added png_free_data() function.
+ Updated makefile.linux and makefile.gccmmx to make directories conditionally.
+ Made cosmetic changes to pngasmrd.h
+ Added png_set_rows() and png_get_rows(), for use with png_read|write_png().
+ Modified png_read_png() to allocate info_ptr->row_pointers only if it
+ hasn't already been allocated.
+
+Version 1.0.5t [March 4, 2000]
+ Changed png_jmp_env() migration aiding macro to png_jmpbuf().
+ Fixed "interlace" typo (should be "interlaced") in contrib/gregbook/read2-x.c
+ Fixed bug with use of PNG_BEFORE_IHDR bit in png_ptr->mode, introduced when
+ PNG_FLAG_HAVE_CHUNK_HEADER was moved into png_ptr->mode in version 1.0.5b
+ Files in contrib/gregbook were revised to use png_jmpbuf() and to select
+ a 24-bit visual if one is available, and to allow abbreviated options.
+ Files in contrib/pngminus were revised to use the png_jmpbuf() macro.
+ Removed spaces in makefile.linux and makefile.gcmmx, introduced in 1.0.5s
+
+Version 1.0.5u [March 5, 2000]
+ Simplified the code that detects old png.h in png.c and pngtest.c
+ Renamed png_spalette (_p, _pp) to png_sPLT_t (_tp, _tpp)
+ Increased precision of rgb_to_gray calculations from 8 to 15 bits and
+ added png_set_rgb_to_gray_fixed() function.
+ Added makefile.bc32 (32-bit Borland C++, C mode)
+
+Version 1.0.5v [March 11, 2000]
+ Added some parentheses to the png_jmpbuf macro definition.
+ Updated references to the zlib home page, which has moved to freesoftware.com.
+ Corrected bugs in documentation regarding png_read_row() and png_write_row().
+ Updated documentation of png_rgb_to_gray calculations in libpng.3/libpng.txt.
+ Renamed makefile.borland,turboc3 back to makefile.bor,tc3 as in version 1.0.3,
+ revised borland makefiles; added makefile.ibmvac3 and makefile.gcc (Cosmin)
+
+Version 1.0.6 [March 20, 2000]
+ Minor revisions of makefile.bor, libpng.txt, and gregbook/rpng2-win.c
+ Added makefile.sggcc (SGI IRIX with gcc)
+
+Version 1.0.6d [April 7, 2000]
+ Changed sprintf() to strcpy() in png_write_sCAL_s() to work without STDIO
+ Added data_length parameter to png_decompress_chunk() function
+ Revised documentation to remove reference to abandoned png_free_chnk functions
+ Fixed an error in png_rgb_to_gray_fixed()
+ Revised example.c, usage of png_destroy_write_struct().
+ Renamed makefile.ibmvac3 to makefile.ibmc, added libpng.icc IBM project file
+ Added a check for info_ptr->free_me&PNG_FREE_TEXT when freeing text in png.c
+ Simplify png_sig_bytes() function to remove use of non-ISO-C strdup().
+
+Version 1.0.6e [April 9, 2000]
+ Added png_data_freer() function.
+ In the code that checks for over-length tRNS chunks, added check of
+ info_ptr->num_trans as well as png_ptr->num_trans (Matthias Benckmann)
+ Minor revisions of libpng.txt/libpng.3.
+ Check for existing data and free it if the free_me flag is set, in png_set_*()
+ and png_handle_*().
+ Only define PNG_WEIGHTED_FILTERS_SUPPORTED when PNG_FLOATING_POINT_SUPPORTED
+ is defined.
+ Changed several instances of PNG_NO_CONSOLE_ID to PNG_NO_STDIO in pngrutil.c
+ and mentioned the purposes of the two macros in libpng.txt/libpng.3.
+
+Version 1.0.6f [April 14, 2000]
+ Revised png_set_iCCP() and png_set_rows() to avoid prematurely freeing data.
+ Add checks in png_set_text() for NULL members of the input text structure.
+ Revised libpng.txt/libpng.3.
+ Removed superfluous prototype for png_set_iTXt from png.h
+ Removed "else" from pngread.c, after png_error(), and changed "0" to "length".
+ Changed several png_errors about malformed ancillary chunks to png_warnings.
+
+Version 1.0.6g [April 24, 2000]
+ Added png_pass-* arrays to pnggccrd.c when PNG_USE_LOCAL_ARRAYS is defined.
+ Relocated paragraph about png_set_background() in libpng.3/libpng.txt
+ and other revisions (Matthias Benckmann)
+ Relocated info_ptr->free_me, png_ptr->free_me, and other info_ptr and
+ png_ptr members to restore binary compatibility with libpng-1.0.5
+ (breaks compatibility with libpng-1.0.6).
+
+Version 1.0.6h [April 24, 2000]
+ Changed shared library so-number pattern from 2.x.y.z to xy.z (this builds
+ libpng.so.10 & libpng.so.10.6h instead of libpng.so.2 & libpng.so.2.1.0.6h)
+ This is a temporary change for test purposes.
+
+Version 1.0.6i [May 2, 2000]
+ Rearranged some members at the end of png_info and png_struct, to put
+ unknown_chunks_num and free_me within the original size of the png_structs
+ and free_me, png_read_user_fn, and png_free_fn within the original png_info,
+ because some old applications allocate the structs directly instead of
+ using png_create_*().
+ Added documentation of user memory functions in libpng.txt/libpng.3
+ Modified png_read_png so that it will use user_allocated row_pointers
+ if present, unless free_me directs that it be freed, and added description
+ of the use of png_set_rows() and png_get_rows() in libpng.txt/libpng.3.
+ Added PNG_LEGACY_SUPPORTED macro, and #ifdef out all new (since version
+ 1.00) members of png_struct and png_info, to regain binary compatibility
+ when you define this macro. Capabilities lost in this event
+ are user transforms (new in version 1.0.0),the user transform pointer
+ (new in version 1.0.2), rgb_to_gray (new in 1.0.5), iCCP, sCAL, sPLT,
+ the high-level interface, and unknown chunks support (all new in 1.0.6).
+ This was necessary because of old applications that allocate the structs
+ directly as authors were instructed to do in libpng-0.88 and earlier,
+ instead of using png_create_*().
+ Added modes PNG_CREATED_READ_STRUCT and PNG_CREATED_WRITE_STRUCT which
+ can be used to detect codes that directly allocate the structs, and
+ code to check these modes in png_read_init() and png_write_init() and
+ generate a libpng error if the modes aren't set and PNG_LEGACY_SUPPORTED
+ was not defined.
+ Added makefile.intel and updated makefile.watcom (Pawel Mrochen)
+
+Version 1.0.6j [May 3, 2000]
+ Overloaded png_read_init() and png_write_init() with macros that convert
+ calls to png_read_init_2() or png_write_init_2() that check the version
+ and structure sizes.
+
+Version 1.0.7beta11 [May 7, 2000]
+ Removed the new PNG_CREATED_READ_STRUCT and PNG_CREATED_WRITE_STRUCT modes
+ which are no longer used.
+ Eliminated the three new members of png_text when PNG_LEGACY_SUPPORTED is
+ defined or when neither PNG_READ_iTXt_SUPPORTED nor PNG_WRITE_iTXT_SUPPORTED
+ is defined.
+ Made PNG_NO_READ|WRITE_iTXt the default setting, to avoid memory
+ overrun when old applications fill the info_ptr->text structure directly.
+ Added PNGAPI macro, and added it to the definitions of all exported functions.
+ Relocated version macro definitions ahead of the includes of zlib.h and
+ pngconf.h in png.h.
+
+Version 1.0.7beta12 [May 12, 2000]
+ Revised pngset.c to avoid a problem with expanding the png_debug macro.
+ Deleted some extraneous defines from pngconf.h
+ Made PNG_NO_CONSOLE_IO the default condition when PNG_BUILD_DLL is defined.
+ Use MSC _RPTn debugging instead of fprintf if _MSC_VER is defined.
+ Added png_access_version_number() function.
+ Check for mask&PNG_FREE_CHNK (for TEXT, SCAL, PCAL) in png_free_data().
+ Expanded libpng.3/libpng.txt information about png_data_freer().
+
+Version 1.0.7beta14 [May 17, 2000] (beta13 was not published)
+ Changed pnggccrd.c and pngvcrd.c to handle bad adaptive filter types as
+ warnings instead of errors, as pngrutil.c does.
+ Set the PNG_INFO_IDAT valid flag in png_set_rows() so png_write_png()
+ will actually write IDATs.
+ Made the default PNG_USE_LOCAL_ARRAYS depend on PNG_DLL instead of WIN32.
+ Make png_free_data() ignore its final parameter except when freeing data
+ that can have multiple instances (text, sPLT, unknowns).
+ Fixed a new bug in png_set_rows().
+ Removed info_ptr->valid tests from png_free_data(), as in version 1.0.5.
+ Added png_set_invalid() function.
+ Fixed incorrect illustrations of png_destroy_write_struct() in example.c.
+
+Version 1.0.7beta15 [May 30, 2000]
+ Revised the deliberately erroneous Linux setjmp code in pngconf.h to produce
+ fewer error messages.
+ Rearranged checks for Z_OK to check the most likely path first in pngpread.c
+ and pngwutil.c.
+ Added checks in pngtest.c for png_create_*() returning NULL, and mentioned
+ in libpng.txt/libpng.3 the need for applications to check this.
+ Changed names of png_default_*() functions in pngtest to pngtest_*().
+ Changed return type of png_get_x|y_offset_*() from png_uint_32 to png_int_32.
+ Fixed some bugs in the unused PNG_INCH_CONVERSIONS functions in pngget.c
+ Set each pointer to NULL after freeing it in png_free_data().
+ Worked around a problem in pngconf.h; AIX's strings.h defines an "index"
+ macro that conflicts with libpng's png_color_16.index. (Dimitri
+ Papadapoulos)
+ Added "msvc" directory with MSVC++ project files (Simon-Pierre Cadieux).
+
+Version 1.0.7beta16 [June 4, 2000]
+ Revised the workaround of AIX string.h "index" bug.
+ Added a check for overlength PLTE chunk in pngrutil.c.
+ Added PNG_NO_POINTER_INDEXING macro to use array-indexing instead of pointer
+ indexing in pngrutil.c and pngwutil.c to accommodate a buggy compiler.
+ Added a warning in png_decompress_chunk() when it runs out of data, e.g.
+ when it tries to read an erroneous PhotoShop iCCP chunk.
+ Added PNG_USE_DLL macro.
+ Revised the copyright/disclaimer/license notice.
+ Added contrib/msvctest directory
+
+Version 1.0.7rc1 [June 9, 2000]
+ Corrected the definition of PNG_TRANSFORM_INVERT_ALPHA (0x0400 not 0x0200)
+ Added contrib/visupng directory (Willem van Schaik)
+
+Version 1.0.7beta18 [June 23, 2000]
+ Revised PNGAPI definition, and pngvcrd.c to work with __GCC__
+ and do not redefine PNGAPI if it is passed in via a compiler directive.
+ Revised visupng/PngFile.c to remove returns from within the Try block.
+ Removed leading underscores from "_PNG_H" and "_PNG_SAVE_BSD_SOURCE" macros.
+ Updated contrib/visupng/cexcept.h to version 1.0.0.
+ Fixed bugs in pngwrite.c and pngwutil.c that prevented writing iCCP chunks.
+
+Version 1.0.7rc2 [June 28, 2000]
+ Updated license to include disclaimers required by UCITA.
+ Fixed "DJBPP" typo in pnggccrd.c introduced in beta18.
+
+Version 1.0.7 [July 1, 2000]
+ Revised the definition of "trans_values" in libpng.3/libpng.txt
+
+Version 1.0.8beta1 [July 8, 2000]
+ Added png_free(png_ptr, key) two places in pngpread.c to stop memory leaks.
+ Changed PNG_NO_STDIO to PNG_NO_CONSOLE_IO, several places in pngrutil.c and
+ pngwutil.c.
+ Changed PNG_EXPORT_VAR to use PNG_IMPEXP, in pngconf.h.
+ Removed unused "#include <assert.h>" from png.c
+ Added WindowsCE support.
+ Revised pnggccrd.c to work with gcc-2.95.2 and in the Cygwin environment.
+
+Version 1.0.8beta2 [July 10, 2000]
+ Added project files to the wince directory and made further revisions
+ of pngtest.c, pngrio.c, and pngwio.c in support of WindowsCE.
+
+Version 1.0.8beta3 [July 11, 2000]
+ Only set the PNG_FLAG_FREE_TRNS or PNG_FREE_TRNS flag in png_handle_tRNS()
+ for indexed-color input files to avoid potential double-freeing trans array
+ under some unusual conditions; problem was introduced in version 1.0.6f.
+ Further revisions to pngtest.c and files in the wince subdirectory.
+
+Version 1.0.8beta4 [July 14, 2000]
+ Added the files pngbar.png and pngbar.jpg to the distribution.
+ Added makefile.cygwin, and cygwin support in pngconf.h
+ Added PNG_NO_ZALLOC_ZERO macro (makes png_zalloc skip zeroing memory)
+
+Version 1.0.8rc1 [July 16, 2000]
+ Revised png_debug() macros and statements to eliminate compiler warnings.
+
+Version 1.0.8 [July 24, 2000]
+ Added png_flush() in pngwrite.c, after png_write_IEND().
+ Updated makefile.hpux to build a shared library.
+
+Version 1.0.9beta1 [November 10, 2000]
+ Fixed typo in scripts/makefile.hpux
+ Updated makevms.com in scripts and contrib/* and contrib/* (Martin Zinser)
+ Fixed seqence-point bug in contrib/pngminus/png2pnm (Martin Zinser)
+ Changed "cdrom.com" in documentation to "libpng.org"
+ Revised pnggccrd.c to get it all working, and updated makefile.gcmmx (Greg).
+ Changed type of "params" from voidp to png_voidp in png_read|write_png().
+ Make sure PNGAPI and PNG_IMPEXP are defined in pngconf.h.
+ Revised the 3 instances of WRITEFILE in pngtest.c.
+ Relocated "msvc" and "wince" project subdirectories into "dll" subdirectory.
+ Updated png.rc in dll/msvc project
+ Revised makefile.dec to define and use LIBPATH and INCPATH
+ Increased size of global png_libpng_ver[] array from 12 to 18 chars.
+ Made global png_libpng_ver[], png_sig[] and png_pass_*[] arrays const.
+ Removed duplicate png_crc_finish() from png_handle_bKGD() function.
+ Added a warning when application calls png_read_update_info() multiple times.
+ Revised makefile.cygwin
+ Fixed bugs in iCCP support in pngrutil.c and pngwutil.c.
+ Replaced png_set_empty_plte_permitted() with png_permit_mng_features().
+
+Version 1.0.9beta2 [November 19, 2000]
+ Renamed the "dll" subdirectory "projects".
+ Added borland project files to "projects" subdirectory.
+ Set VS_FF_PRERELEASE and VS_FF_PATCHED flags in msvc/png.rc when appropriate.
+ Add error message in png_set_compression_buffer_size() when malloc fails.
+
+Version 1.0.9beta3 [November 23, 2000]
+ Revised PNG_LIBPNG_BUILD_TYPE macro in png.h, used in the msvc project.
+ Removed the png_flush() in pngwrite.c that crashes some applications
+ that don't set png_output_flush_fn.
+ Added makefile.macosx and makefile.aix to scripts directory.
+
+Version 1.0.9beta4 [December 1, 2000]
+ Change png_chunk_warning to png_warning in png_check_keyword().
+ Increased the first part of msg buffer from 16 to 18 in png_chunk_error().
+
+Version 1.0.9beta5 [December 15, 2000]
+ Added support for filter method 64 (for PNG datastreams embedded in MNG).
+
+Version 1.0.9beta6 [December 18, 2000]
+ Revised png_set_filter() to accept filter method 64 when appropriate.
+ Added new PNG_HAVE_PNG_SIGNATURE bit to png_ptr->mode and use it to
+ help prevent applications from using MNG features in PNG datastreams.
+ Added png_permit_mng_features() function.
+ Revised libpng.3/libpng.txt. Changed "filter type" to "filter method".
+
+Version 1.0.9rc1 [December 23, 2000]
+ Revised test for PNG_HAVE_PNG_SIGNATURE in pngrutil.c
+ Fixed error handling of unknown compression type in png_decompress_chunk().
+ In pngconf.h, define __cdecl when _MSC_VER is defined.
+
+Version 1.0.9beta7 [December 28, 2000]
+ Changed PNG_TEXT_COMPRESSION_zTXt to PNG_COMPRESSION_TYPE_BASE several places.
+ Revised memory management in png_set_hIST and png_handle_hIST in a backward
+ compatible manner. PLTE and tRNS were revised similarly.
+ Revised the iCCP chunk reader to ignore trailing garbage.
+
+Version 1.0.9beta8 [January 12, 2001]
+ Moved pngasmrd.h into pngconf.h.
+ Improved handling of out-of-spec garbage iCCP chunks generated by PhotoShop.
+
+Version 1.0.9beta9 [January 15, 2001]
+ Added png_set_invalid, png_permit_mng_features, and png_mmx_supported to
+ wince and msvc project module definition files.
+ Minor revision of makefile.cygwin.
+ Fixed bug with progressive reading of narrow interlaced images in pngpread.c
+
+Version 1.0.9beta10 [January 16, 2001]
+ Do not typedef png_FILE_p in pngconf.h when PNG_NO_STDIO is defined.
+ Fixed "png_mmx_supported" typo in project definition files.
+
+Version 1.0.9beta11 [January 19, 2001]
+ Updated makefile.sgi to make shared library.
+ Removed png_mmx_support() function and disabled PNG_MNG_FEATURES_SUPPORTED
+ by default, for the benefit of DLL forward compatibility. These will
+ be re-enabled in version 1.2.0.
+
+Version 1.0.9rc2 [January 22, 2001]
+ Revised cygwin support.
+
+Version 1.0.9 [January 31, 2001]
+ Added check of cygwin's ALL_STATIC in pngconf.h
+ Added "-nommx" parameter to contrib/gregbook/rpng2-win and rpng2-x demos.
+
+Version 1.0.10beta1 [March 14, 2001]
+ Revised makefile.dec, makefile.sgi, and makefile.sggcc; added makefile.hpgcc.
+ Reformatted libpng.3 to eliminate bad line breaks.
+ Added checks for _mmx_supported in the read_filter_row function of pnggccrd.c
+ Added prototype for png_mmx_support() near the top of pnggccrd.c
+ Moved some error checking from png_handle_IHDR to png_set_IHDR.
+ Added PNG_NO_READ_SUPPORTED and PNG_NO_WRITE_SUPPORTED macros.
+ Revised png_mmx_support() function in pnggccrd.c
+ Restored version 1.0.8 PNG_WRITE_EMPTY_PLTE_SUPPORTED behavior in pngwutil.c
+ Fixed memory leak in contrib/visupng/PngFile.c
+ Fixed bugs in png_combine_row() in pnggccrd.c and pngvcrd.c (C version)
+ Added warnings when retrieving or setting gamma=0.
+ Increased the first part of msg buffer from 16 to 18 in png_chunk_warning().
+
+Version 1.0.10rc1 [March 23, 2001]
+ Changed all instances of memcpy, strcpy, and strlen to png_memcpy, png_strcpy,
+ and png_strlen.
+ Revised png_mmx_supported() function in pnggccrd.c to return proper value.
+ Fixed bug in progressive reading (pngpread.c) with small images (height < 8).
+
+Version 1.0.10 [March 30, 2001]
+ Deleted extraneous space (introduced in 1.0.9) from line 42 of makefile.cygwin
+ Added beos project files (Chris Herborth)
+
+Version 1.0.11beta1 [April 3, 2001]
+ Added type casts on several png_malloc() calls (Dimitri Papadapoulos).
+ Removed a no-longer needed AIX work-around from pngconf.h
+ Changed several "//" single-line comments to C-style in pnggccrd.c
+
+Version 1.0.11beta2 [April 11, 2001]
+ Removed PNGAPI from several functions whose prototypes did not have PNGAPI.
+ Updated scripts/pngos2.def
+
+Version 1.0.11beta3 [April 14, 2001]
+ Added checking the results of many instances of png_malloc() for NULL
+
+Version 1.0.11beta4 [April 20, 2001]
+ Undid the changes from version 1.0.11beta3. Added a check for NULL return
+ from user's malloc_fn().
+ Removed some useless type casts of the NULL pointer.
+ Added makefile.netbsd
+
+Version 1.0.11 [April 27, 2001]
+ Revised makefile.netbsd
+
+Version 1.0.12beta1 [May 14, 2001]
+ Test for Windows platform in pngconf.h when including malloc.h (Emmanuel Blot)
+ Updated makefile.cygwin and handling of Cygwin's ALL_STATIC in pngconf.h
+ Added some never-to-be-executed code in pnggccrd.c to quiet compiler warnings.
+ Eliminated the png_error about apps using png_read|write_init(). Instead,
+ libpng will reallocate the png_struct and info_struct if they are too small.
+ This retains future binary compatibility for old applications written for
+ libpng-0.88 and earlier.
+
+Version 1.2.0beta1 [May 6, 2001]
+ Bumped DLLNUM to 2.
+ Re-enabled PNG_MNG_FEATURES_SUPPORTED and enabled PNG_ASSEMBLER_CODE_SUPPORTED
+ by default.
+ Added runtime selection of MMX features.
+ Added png_set_strip_error_numbers function and related macros.
+
+Version 1.2.0beta2 [May 7, 2001]
+ Finished merging 1.2.0beta1 with version 1.0.11
+ Added a check for attempts to read or write PLTE in grayscale PNG datastreams.
+
+Version 1.2.0beta3 [May 17, 2001]
+ Enabled user memory function by default.
+ Modified png_create_struct so it passes user mem_ptr to user memory allocator.
+ Increased png_mng_features flag from png_byte to png_uint_32.
+ Bumped shared-library (so-number) and dll-number to 3.
+
+Version 1.2.0beta4 [June 23, 2001]
+ Check for missing profile length field in iCCP chunk and free chunk_data
+ in case of truncated iCCP chunk.
+ Bumped shared-library number to 3 in makefile.sgi and makefile.sggcc
+ Bumped dll-number from 2 to 3 in makefile.cygwin
+ Revised contrib/gregbook/rpng*-x.c to avoid a memory leak and to exit cleanly
+ if user attempts to run it on an 8-bit display.
+ Updated contrib/gregbook
+ Use png_malloc instead of png_zalloc to allocate palette in pngset.c
+ Updated makefile.ibmc
+ Added some typecasts to eliminate gcc 3.0 warnings. Changed prototypes
+ of png_write_oFFS width and height from png_uint_32 to png_int_32.
+ Updated example.c
+ Revised prototypes for png_debug_malloc and png_debug_free in pngtest.c
+
+Version 1.2.0beta5 [August 8, 2001]
+ Revised contrib/gregbook
+ Revised makefile.gcmmx
+ Revised pnggccrd.c to conditionally compile some thread-unsafe code only
+ when PNG_THREAD_UNSAFE_OK is defined.
+ Added tests to prevent pngwutil.c from writing a bKGD or tRNS chunk with
+ value exceeding 2^bit_depth-1
+ Revised makefile.sgi and makefile.sggcc
+ Replaced calls to fprintf(stderr,...) with png_warning() in pnggccrd.c
+ Removed restriction that do_invert_mono only operate on 1-bit opaque files
+
+Version 1.2.0 [September 1, 2001]
+ Changed a png_warning() to png_debug() in pnggccrd.c
+ Fixed contrib/gregbook/rpng-x.c, rpng2-x.c to avoid crash with XFreeGC().
+
+Version 1.2.1beta1 [October 19, 2001]
+ Revised makefile.std in contrib/pngminus
+ Include background_1 in png_struct regardless of gamma support.
+ Revised makefile.netbsd and makefile.macosx, added makefile.darwin.
+ Revised example.c to provide more details about using row_callback().
+
+Version 1.2.1beta2 [October 25, 2001]
+ Added type cast to each NULL appearing in a function call, except for
+ WINCE functions.
+ Added makefile.so9.
+
+Version 1.2.1beta3 [October 27, 2001]
+ Removed type casts from all NULLs.
+ Simplified png_create_struct_2().
+
+Version 1.2.1beta4 [November 7, 2001]
+ Revised png_create_info_struct() and png_creat_struct_2().
+ Added error message if png_write_info() was omitted.
+ Type cast NULLs appearing in function calls when _NO_PROTO or
+ PNG_TYPECAST_NULL is defined.
+
+Version 1.2.1rc1 [November 24, 2001]
+ Type cast NULLs appearing in function calls except when PNG_NO_TYPECAST_NULL
+ is defined.
+ Changed typecast of "size" argument to png_size_t in pngmem.c calls to
+ the user malloc_fn, to agree with the prototype in png.h
+ Added a pop/push operation to pnggccrd.c, to preserve Eflag (Maxim Sobolev)
+ Updated makefile.sgi to recognize LIBPATH and INCPATH.
+ Updated various makefiles so "make clean" does not remove previous major
+ version of the shared library.
+
+Version 1.2.1rc2 [December 4, 2001]
+ Always allocate 256-entry internal palette, hist, and trans arrays, to
+ avoid out-of-bounds memory reference caused by invalid PNG datastreams.
+ Added a check for prefix_length > data_length in iCCP chunk handler.
+
+Version 1.2.1 [December 7, 2001]
+ None.
+
+Version 1.2.2beta1 [February 22, 2002]
+ Fixed a bug with reading the length of iCCP profiles (Larry Reeves).
+ Revised makefile.linux, makefile.gcmmx, and makefile.sgi to generate
+ libpng.a, libpng12.so (not libpng.so.3), and libpng12/png.h
+ Revised makefile.darwin to remove "-undefined suppress" option.
+ Added checks for gamma and chromaticity values over 21474.83, which exceed
+ the limit for PNG unsigned 32-bit integers when encoded.
+ Revised calls to png_create_read_struct() and png_create_write_struct()
+ for simpler debugging.
+ Revised png_zalloc() so zlib handles errors (uses PNG_FLAG_MALLOC_NULL_MEM_OK)
+
+Version 1.2.2beta2 [February 23, 2002]
+ Check chunk_length and idat_size for invalid (over PNG_MAX_UINT) lengths.
+ Check for invalid image dimensions in png_get_IHDR.
+ Added missing "fi;" in the install target of the SGI makefiles.
+ Added install-static to all makefiles that make shared libraries.
+ Always do gamma compensation when image is partially transparent.
+
+Version 1.2.2beta3 [March 7, 2002]
+ Compute background.gray and background_1.gray even when color_type is RGB
+ in case image gets reduced to gray later.
+ Modified shared-library makefiles to install pkgconfig/libpngNN.pc.
+ Export (with PNGAPI) png_zalloc, png_zfree, and png_handle_as_unknown
+ Removed unused png_write_destroy_info prototype from png.h
+ Eliminated incorrect use of width_mmx from pnggccrd.c in pixel_bytes == 8 case
+ Added install-shared target to all makefiles that make shared libraries.
+ Stopped a double free of palette, hist, and trans when not using free_me.
+ Added makefile.32sunu for Sun Ultra 32 and makefile.64sunu for Sun Ultra 64.
+
+Version 1.2.2beta4 [March 8, 2002]
+ Compute background.gray and background_1.gray even when color_type is RGB
+ in case image gets reduced to gray later (Jason Summers).
+ Relocated a misplaced /bin/rm in the "install-shared" makefile targets
+ Added PNG_1_0_X macro which can be used to build a 1.0.x-compatible library.
+
+Version 1.2.2beta5 [March 26, 2002]
+ Added missing PNGAPI to several function definitions.
+ Check for invalid bit_depth or color_type in png_get_IHDR(), and
+ check for missing PLTE or IHDR in png_push_read_chunk() (Matthias Clasen).
+ Revised iTXt support to accept NULL for lang and lang_key.
+ Compute gamma for color components of background even when color_type is gray.
+ Changed "()" to "{}" in scripts/libpng.pc.in.
+ Revised makefiles to put png.h and pngconf.h only in $prefix/include/libpngNN
+ Revised makefiles to make symlink to libpng.so.NN in addition to libpngNN.so
+
+Version 1.2.2beta6 [March 31, 2002]
+
+Version 1.0.13beta1 [March 31, 2002]
+ Prevent png_zalloc() from trying to memset memory that it failed to acquire.
+ Add typecasts of PNG_MAX_UINT in pngset_cHRM_fixed() (Matt Holgate).
+ Ensure that the right function (user or default) is used to free the
+ png_struct after an error in png_create_read_struct_2().
+
+Version 1.2.2rc1 [April 7, 2002]
+
+Version 1.0.13rc1 [April 7, 2002]
+ Save the ebx register in pnggccrd.c (Sami Farin)
+ Add "mem_ptr = png_ptr->mem_ptr" in png_destroy_write_struct() (Paul Gardner).
+ Updated makefiles to put headers in include/libpng and remove old include/*.h.
+
+Version 1.2.2 [April 15, 2002]
+
+Version 1.0.13 [April 15, 2002]
+ Revised description of png_set_filter() in libpng.3/libpng.txt.
+ Revised makefile.netbsd and added makefile.neNNbsd and makefile.freebsd
+
+Version 1.0.13patch01 [April 17, 2002]
+
+Version 1.2.2patch01 [April 17, 2002]
+ Changed ${PNGMAJ}.${PNGVER} bug to ${PNGVER} in makefile.sgi and
+ makefile.sggcc
+ Fixed VER -> PNGVER typo in makefile.macosx and added install-static to
+ install
+ Added install: target to makefile.32sunu and makefile.64sunu
+
+Version 1.0.13patch03 [April 18, 2002]
+
+Version 1.2.2patch03 [April 18, 2002]
+ Revised 15 makefiles to link libpng.a to libpngNN.a and the include libpng
+ subdirectory to libpngNN subdirectory without the full pathname.
+ Moved generation of libpng.pc from "install" to "all" in 15 makefiles.
+
+Version 1.2.3rc1 [April 28, 2002]
+ Added install-man target to 15 makefiles (Dimitri Papadopolous-Orfanos).
+ Added $(DESTDIR) feature to 24 makefiles (Tim Mooney)
+ Fixed bug with $prefix, should be $(prefix) in makefile.hpux.
+ Updated cygwin-specific portion of pngconf.h and revised makefile.cygwin
+ Added a link from libpngNN.pc to libpng.pc in 15 makefiles.
+ Added links from include/libpngNN/*.h to include/*.h in 24 makefiles.
+ Revised makefile.darwin to make relative links without full pathname.
+ Added setjmp() at the end of png_create_*_struct_2() in case user forgets
+ to put one in their application.
+ Restored png_zalloc() and png_zfree() prototypes to version 1.2.1 and
+ removed them from module definition files.
+
+Version 1.2.3rc2 [May 1, 2002]
+ Fixed bug in reporting number of channels in pngget.c and pngset.c,
+ that was introduced in version 1.2.2beta5.
+ Exported png_zalloc(), png_zfree(), png_default_read(), png_default_write(),
+ png_default_flush(), and png_push_fill_buffer() and included them in
+ module definition files.
+ Added "libpng.pc" dependency to the "install-shared" target in 15 makefiles.
+
+Version 1.2.3rc3 [May 1, 2002]
+ Revised prototype for png_default_flush()
+ Remove old libpng.pc and libpngNN.pc before installing new ones.
+
+Version 1.2.3rc4 [May 2, 2002]
+ Typos in *.def files (png_default_read|write -> png_default_read|write_data)
+ In makefiles, changed rm libpng.NN.pc to rm libpngNN.pc
+ Added libpng-config and libpngNN-config and modified makefiles to install
+ them.
+ Changed $(MANPATH) to $(DESTDIR)$(MANPATH) in makefiles
+ Added "Win32 DLL VB" configuration to projects/msvc/libpng.dsp
+
+Version 1.2.3rc5 [May 11, 2002]
+ Changed "error" and "message" in prototypes to "error_message" and
+ "warning_message" to avoid namespace conflict.
+ Revised 15 makefiles to build libpng-config from libpng-config-*.in
+ Once more restored png_zalloc and png_zfree to regular nonexported form.
+ Restored png_default_read|write_data, png_default_flush, png_read_fill_buffer
+ to nonexported form, but with PNGAPI, and removed them from module def
+ files.
+
+Version 1.2.3rc6 [May 14, 2002]
+ Removed "PNGAPI" from png_zalloc() and png_zfree() in png.c
+ Changed "Gz" to "Gd" in projects/msvc/libpng.dsp and zlib.dsp.
+ Removed leftover libpng-config "sed" script from four makefiles.
+ Revised libpng-config creating script in 16 makefiles.
+
+Version 1.2.3 [May 22, 2002]
+ Revised libpng-config target in makefile.cygwin.
+ Removed description of png_set_mem_fn() from documentation.
+ Revised makefile.freebsd.
+ Minor cosmetic changes to 15 makefiles, e.g., $(DI) = $(DESTDIR)/$(INCDIR).
+ Revised projects/msvc/README.txt
+ Changed -lpng to -lpngNN in LDFLAGS in several makefiles.
+
+Version 1.2.4beta1 [May 24, 2002]
+ Added libpng.pc and libpng-config to "all:" target in 16 makefiles.
+ Fixed bug in 16 makefiles: $(DESTDIR)/$(LIBPATH) to $(DESTDIR)$(LIBPATH)
+ Added missing "\" before closing double quote in makefile.gcmmx.
+ Plugged various memory leaks; added png_malloc_warn() and png_set_text_2()
+ functions.
+
+Version 1.2.4beta2 [June 25, 2002]
+ Plugged memory leak of png_ptr->current_text (Matt Holgate).
+ Check for buffer overflow before reading CRC in pngpread.c (Warwick Allison)
+ Added -soname to the loader flags in makefile.dec, makefile.sgi, and
+ makefile.sggcc.
+ Added "test-installed" target to makefile.linux, makefile.gcmmx,
+ makefile.sgi, and makefile.sggcc.
+
+Version 1.2.4beta3 [June 28, 2002]
+ Plugged memory leak of row_buf in pngtest.c when there is a png_error().
+ Detect buffer overflow in pngpread.c when IDAT is corrupted with extra data.
+ Added "test-installed" target to makefile.32sunu, makefile.64sunu,
+ makefile.beos, makefile.darwin, makefile.dec, makefile.macosx,
+ makefile.solaris, makefile.hpux, makefile.hpgcc, and makefile.so9.
+
+Version 1.2.4rc1 and 1.0.14rc1 [July 2, 2002]
+ Added "test-installed" target to makefile.cygwin and makefile.sco.
+ Revised pnggccrd.c to be able to back out version 1.0.x via PNG_1_0_X macro.
+
+Version 1.2.4 and 1.0.14 [July 8, 2002]
+ Changed png_warning() to png_error() when width is too large to process.
+
+Version 1.2.4patch01 [July 20, 2002]
+ Revised makefile.cygwin to use DLL number 12 instead of 13.
+
+Version 1.2.5beta1 [August 6, 2002]
+ Added code to contrib/gregbook/readpng2.c to ignore unused chunks.
+ Replaced toucan.png in contrib/gregbook (it has been corrupt since 1.0.11)
+ Removed some stray *.o files from contrib/gregbook.
+ Changed png_error() to png_warning() about "Too much data" in pngpread.c
+ and about "Extra compressed data" in pngrutil.c.
+ Prevent png_ptr->pass from exceeding 7 in png_push_finish_row().
+ Updated makefile.hpgcc
+ Updated png.c and pnggccrd.c handling of return from png_mmx_support()
+
+Version 1.2.5beta2 [August 15, 2002]
+ Only issue png_warning() about "Too much data" in pngpread.c when avail_in
+ is nonzero.
+ Updated makefiles to install a separate libpng.so.3 with its own rpath.
+
+Version 1.2.5rc1 and 1.0.15rc1 [August 24, 2002]
+ Revised makefiles to not remove previous minor versions of shared libraries.
+
+Version 1.2.5rc2 and 1.0.15rc2 [September 16, 2002]
+ Revised 13 makefiles to remove "-lz" and "-L$(ZLIBLIB)", etc., from shared
+ library loader directive.
+ Added missing "$OBJSDLL" line to makefile.gcmmx.
+ Added missing "; fi" to makefile.32sunu.
+
+Version 1.2.5rc3 and 1.0.15rc3 [September 18, 2002]
+ Revised libpng-config script.
+
+Version 1.2.5 and 1.0.15 [October 3, 2002]
+ Revised makefile.macosx, makefile.darwin, makefile.hpgcc, and makefile.hpux,
+ and makefile.aix.
+ Relocated two misplaced PNGAPI lines in pngtest.c
+
+Version 1.2.6beta1 [October 22, 2002]
+ Commented out warning about uninitialized mmx_support in pnggccrd.c.
+ Changed "IBMCPP__" flag to "__IBMCPP__" in pngconf.h.
+ Relocated two more misplaced PNGAPI lines in pngtest.c
+ Fixed memory overrun bug in png_do_read_filler() with 16-bit datastreams,
+ introduced in version 1.0.2.
+ Revised makefile.macosx, makefile.dec, makefile.aix, and makefile.32sunu.
+
+Version 1.2.6beta2 [November 1, 2002]
+ Added libpng-config "--ldopts" output.
+ Added "AR=ar" and "ARFLAGS=rc" and changed "ar rc" to "$(AR) $(ARFLAGS)"
+ in makefiles.
+
+Version 1.2.6beta3 [July 18, 2004]
+ Reverted makefile changes from version 1.2.6beta2 and some of the changes
+ from version 1.2.6beta1; these will be postponed until version 1.2.7.
+ Version 1.2.6 is going to be a simple bugfix release.
+ Changed the one instance of "ln -sf" to "ln -f -s" in each Sun makefile.
+ Fixed potential overrun in pngerror.c by using strncpy instead of memcpy.
+ Added "#!/bin/sh" at the top of configure, for recognition of the
+ 'x' flag under Cygwin (Cosmin).
+ Optimized vacuous tests that silence compiler warnings, in png.c (Cosmin).
+ Added support for PNG_USER_CONFIG, in pngconf.h (Cosmin).
+ Fixed the special memory handler for Borland C under DOS, in pngmem.c
+ (Cosmin).
+ Removed some spurious assignments in pngrutil.c (Cosmin).
+ Replaced 65536 with 65536L, and 0xffff with 0xffffL, to silence warnings
+ on 16-bit platforms (Cosmin).
+ Enclosed shift op expressions in parentheses, to silence warnings (Cosmin).
+ Used proper type png_fixed_point, to avoid problems on 16-bit platforms,
+ in png_handle_sRGB() (Cosmin).
+ Added compression_type to png_struct, and optimized the window size
+ inside the deflate stream (Cosmin).
+ Fixed definition of isnonalpha(), in pngerror.c and pngrutil.c (Cosmin).
+ Fixed handling of unknown chunks that come after IDAT (Cosmin).
+ Allowed png_error() and png_warning() to work even if png_ptr == NULL
+ (Cosmin).
+ Replaced row_info->rowbytes with row_bytes in png_write_find_filter()
+ (Cosmin).
+ Fixed definition of PNG_LIBPNG_VER_DLLNUM (Simon-Pierre).
+ Used PNG_LIBPNG_VER and PNG_LIBPNG_VER_STRING instead of the hardcoded
+ values in png.c (Simon-Pierre, Cosmin).
+ Initialized png_libpng_ver[] with PNG_LIBPNG_VER_STRING (Simon-Pierre).
+ Replaced PNG_LIBPNG_VER_MAJOR with PNG_LIBPNG_VER_DLLNUM in png.rc
+ (Simon-Pierre).
+ Moved the definition of PNG_HEADER_VERSION_STRING near the definitions
+ of the other PNG_LIBPNG_VER_... symbols in png.h (Cosmin).
+ Relocated #ifndef PNGAPI guards in pngconf.h (Simon-Pierre, Cosmin).
+ Updated scripts/makefile.vc(a)win32 (Cosmin).
+ Updated the MSVC project (Simon-Pierre, Cosmin).
+ Updated the Borland C++ Builder project (Cosmin).
+ Avoided access to asm_flags in pngvcrd.c, if PNG_1_0_X is defined (Cosmin).
+ Commented out warning about uninitialized mmx_support in pngvcrd.c (Cosmin).
+ Removed scripts/makefile.bd32 and scripts/pngdef.pas (Cosmin).
+ Added extra guard around inclusion of Turbo C memory headers, in pngconf.h
+ (Cosmin).
+ Renamed projects/msvc/ to projects/visualc6/, and projects/borland/ to
+ projects/cbuilder5/ (Cosmin).
+ Moved projects/visualc6/png32ms.def to scripts/pngw32.def,
+ and projects/visualc6/png.rc to scripts/pngw32.rc (Cosmin).
+ Added projects/visualc6/pngtest.dsp; removed contrib/msvctest/ (Cosmin).
+ Changed line endings to DOS style in cbuilder5 and visualc6 files, even
+ in the tar.* distributions (Cosmin).
+ Updated contrib/visupng/VisualPng.dsp (Cosmin).
+ Updated contrib/visupng/cexcept.h to version 2.0.0 (Cosmin).
+ Added a separate distribution with "configure" and supporting files (Junichi).
+
+Version 1.2.6beta4 [July 28, 2004]
+ Added user ability to change png_size_t via a PNG_SIZE_T macro.
+ Added png_sizeof() and png_convert_size() functions.
+ Added PNG_SIZE_MAX (maximum value of a png_size_t variable.
+ Added check in png_malloc_default() for (size_t)size != (png_uint_32)size
+ which would indicate an overflow.
+ Changed sPLT failure action from png_error to png_warning and abandon chunk.
+ Changed sCAL and iCCP failures from png_error to png_warning and abandon.
+ Added png_get_uint_31(png_ptr, buf) function.
+ Added PNG_UINT_32_MAX macro.
+ Renamed PNG_MAX_UINT to PNG_UINT_31_MAX.
+ Made png_zalloc() issue a png_warning and return NULL on potential
+ overflow.
+ Turn on PNG_NO_ZALLOC_ZERO by default in version 1.2.x
+ Revised "clobber list" in pnggccrd.c so it will compile under gcc-3.4.
+ Revised Borland portion of png_malloc() to return NULL or issue
+ png_error() according to setting of PNG_FLAG_MALLOC_NULL_MEM_OK.
+ Added PNG_NO_SEQUENTIAL_READ_SUPPORTED macro to conditionally remove
+ sequential read support.
+ Added some "#if PNG_WRITE_SUPPORTED" blocks.
+ Added #ifdef to remove some redundancy in png_malloc_default().
+ Use png_malloc instead of png_zalloc to allocate the pallete.
+
+Version 1.0.16rc1 and 1.2.6rc1 [August 4, 2004]
+ Fixed buffer overflow vulnerability in png_handle_tRNS()
+ Fixed integer arithmetic overflow vulnerability in png_read_png().
+ Fixed some harmless bugs in png_handle_sBIT, etc, that would cause
+ duplicate chunk types to go undetected.
+ Fixed some timestamps in the -config version
+ Rearranged order of processing of color types in png_handle_tRNS().
+ Added ROWBYTES macro to calculate rowbytes without integer overflow.
+ Updated makefile.darwin and removed makefile.macosx from scripts directory.
+ Imposed default one million column, one-million row limits on the image
+ dimensions, and added png_set_user_limits() function to override them.
+ Revised use of PNG_SET_USER_LIMITS_SUPPORTED macro.
+ Fixed wrong cast of returns from png_get_user_width|height_max().
+ Changed some "keep the compiler happy" from empty statements to returns,
+ Revised libpng.txt to remove 1.2.x stuff from the 1.0.x distribution
+
+Version 1.0.16rc2 and 1.2.6rc2 [August 7, 2004]
+ Revised makefile.darwin and makefile.solaris. Removed makefile.macosx.
+ Revised pngtest's png_debug_malloc() to use png_malloc() instead of
+ png_malloc_default() which is not supposed to be exported.
+ Fixed off-by-one error in one of the conversions to PNG_ROWBYTES() in
+ pngpread.c. Bug was introduced in 1.2.6rc1.
+ Fixed bug in RGB to RGBX transformation introduced in 1.2.6rc1.
+ Fixed old bug in RGB to Gray transformation.
+ Fixed problem with 64-bit compilers by casting arguments to abs()
+ to png_int_32.
+ Changed "ln -sf" to "ln -f -s" in three makefiles (solaris, sco, so9).
+ Changed "HANDLE_CHUNK_*" to "PNG_HANDLE_CHUNK_*" (Cosmin)
+ Added "-@/bin/rm -f $(DL)/$(LIBNAME).so.$(PNGMAJ)" to 15 *NIX makefiles.
+ Added code to update the row_info->colortype in png_do_read_filler() (MSB).
+
+Version 1.0.16rc3 and 1.2.6rc3 [August 9, 2004]
+ Eliminated use of "abs()" in testing cHRM and gAMA values, to avoid
+ trouble with some 64-bit compilers. Created PNG_OUT_OF_RANGE() macro.
+ Revised documentation of png_set_keep_unknown_chunks().
+ Check handle_as_unknown status in pngpread.c, as in pngread.c previously.
+ Moved "PNG_HANDLE_CHUNK_*" macros out of PNG_INTERNAL section of png.h
+ Added "rim" definitions for CONST4 and CONST6 in pnggccrd.c
+
+Version 1.0.16rc4 and 1.2.6rc4 [August 10, 2004]
+ Fixed mistake in pngtest.c introduced in 1.2.6rc2 (declaration of
+ "pinfo" was out of place).
+
+Version 1.0.16rc5 and 1.2.6rc5 [August 10, 2004]
+ Moved "PNG_HANDLE_CHUNK_*" macros out of PNG_ASSEMBLER_CODE_SUPPORTED
+ section of png.h where they were inadvertently placed in version rc3.
+
+Version 1.2.6 and 1.0.16 [August 15, 2004]
+ Revised pngtest so memory allocation testing is only done when PNG_DEBUG==1.
+
+Version 1.2.7beta1 [August 26, 2004]
+ Removed unused pngasmrd.h file.
+ Removed references to uu.net for archived files. Added references to
+ PNG Spec (second edition) and the PNG ISO/IEC Standard.
+ Added "test-dd" target in 15 makefiles, to run pngtest in DESTDIR.
+ Fixed bug with "optimized window size" in the IDAT datastream, that
+ causes libpng to write PNG files with incorrect zlib header bytes.
+
+Version 1.2.7beta2 [August 28, 2004]
+ Fixed bug with sCAL chunk and big-endian machines (David Munro).
+ Undid new code added in 1.2.6rc2 to update the color_type in
+ png_set_filler().
+ Added png_set_add_alpha() that updates color type.
+
+Version 1.0.17rc1 and 1.2.7rc1 [September 4, 2004]
+ Revised png_set_strip_filler() to not remove alpha if color_type has alpha.
+
+Version 1.2.7 and 1.0.17 [September 12, 2004]
+ Added makefile.hp64
+ Changed projects/msvc/png32ms.def to scripts/png32ms.def in makefile.cygwin
+
+Version 1.2.8beta1 [November 1, 2004]
+ Fixed bug in png_text_compress() that would fail to complete a large block.
+ Fixed bug, introduced in libpng-1.2.7, that overruns a buffer during
+ strip alpha operation in png_do_strip_filler().
+ Added PNG_1_2_X definition in pngconf.h
+ Use #ifdef to comment out png_info_init in png.c and png_read_init in
+ pngread.c (as of 1.3.0)
+
+Version 1.2.8beta2 [November 2, 2004]
+ Reduce color_type to a nonalpha type after strip alpha operation in
+ png_do_strip_filler().
+
+Version 1.2.8beta3 [November 3, 2004]
+ Revised definitions of PNG_MAX_UINT_32, PNG_MAX_SIZE, and PNG_MAXSUM
+
+Version 1.2.8beta4 [November 12, 2004]
+ Fixed (again) definition of PNG_LIBPNG_VER_DLLNUM in png.h (Cosmin).
+ Added PNG_LIBPNG_BUILD_PRIVATE in png.h (Cosmin).
+ Set png_ptr->zstream.data_type to Z_BINARY, to avoid unnecessary detection
+ of data type in deflate (Cosmin).
+ Deprecated but continue to support SPECIALBUILD and PRIVATEBUILD in favor of
+ PNG_LIBPNG_BUILD_SPECIAL_STRING and PNG_LIBPNG_BUILD_PRIVATE_STRING.
+
+Version 1.2.8beta5 [November 20, 2004]
+ Use png_ptr->flags instead of png_ptr->transformations to pass
+ PNG_STRIP_ALPHA info to png_do_strip_filler(), to preserve ABI
+ compatibility.
+ Revised handling of SPECIALBUILD, PRIVATEBUILD,
+ PNG_LIBPNG_BUILD_SPECIAL_STRING and PNG_LIBPNG_BUILD_PRIVATE_STRING.
+
+Version 1.2.8rc1 [November 24, 2004]
+ Moved handling of BUILD macros from pngconf.h to png.h
+ Added definition of PNG_LIBPNG_BASE_TYPE in png.h, inadvertently
+ omitted from beta5.
+ Revised scripts/pngw32.rc
+ Despammed mailing addresses by masking "@" with "at".
+ Inadvertently installed a supposedly faster test version of pngrutil.c
+
+Version 1.2.8rc2 [November 26, 2004]
+ Added two missing "\" in png.h
+ Change tests in pngread.c and pngpread.c to
+ if (png_ptr->transformations || (png_ptr->flags&PNG_FLAG_STRIP_ALPHA))
+ png_do_read_transformations(png_ptr);
+
+Version 1.2.8rc3 [November 28, 2004]
+ Reverted pngrutil.c to version libpng-1.2.8beta5.
+ Added scripts/makefile.elf with supporting code in pngconf.h for symbol
+ versioning (John Bowler).
+
+Version 1.2.8rc4 [November 29, 2004]
+ Added projects/visualc7 (Simon-pierre).
+
+Version 1.2.8rc5 [November 29, 2004]
+ Fixed new typo in scripts/pngw32.rc
+
+Version 1.2.8 [December 3, 2004]
+ Removed projects/visualc7, added projects/visualc71.
+
+Version 1.2.9beta1 [February 21, 2006]
+ Initialized some structure members in pngwutil.c to avoid gcc-4.0.0 complaints
+ Revised man page and libpng.txt to make it clear that one should not call
+ png_read_end or png_write_end after png_read_png or png_write_png.
+ Updated references to png-mng-implement mailing list.
+ Fixed an incorrect typecast in pngrutil.c
+ Added PNG_NO_READ_SUPPORTED conditional for making a write-only library.
+ Added PNG_NO_WRITE_INTERLACING_SUPPORTED conditional.
+ Optimized alpha-inversion loops in pngwtran.c
+ Moved test for nonzero gamma outside of png_build_gamma_table() in pngrtran.c
+ Make sure num_trans is <= 256 before copying data in png_set_tRNS().
+ Make sure num_palette is <= 256 before copying data in png_set_PLTE().
+ Interchanged order of write_swap_alpha and write_invert_alpha transforms.
+ Added parentheses in the definition of PNG_LIBPNG_BUILD_TYPE (Cosmin).
+ Optimized zlib window flag (CINFO) in contrib/pngsuite/*.png (Cosmin).
+ Updated scripts/makefile.bc32 for Borland C++ 5.6 (Cosmin).
+ Exported png_get_uint_32, png_save_uint_32, png_get_uint_16, png_save_uint_16,
+ png_get_int_32, png_save_int_32, png_get_uint_31 (Cosmin).
+ Added type cast (png_byte) in png_write_sCAL() (Cosmin).
+ Fixed scripts/makefile.cygwin (Christian Biesinger, Cosmin).
+ Default iTXt support was inadvertently enabled.
+
+Version 1.2.9beta2 [February 21, 2006]
+ Check for png_rgb_to_gray and png_gray_to_rgb read transformations before
+ checking for png_read_dither in pngrtran.c
+ Revised checking of chromaticity limits to accommodate extended RGB
+ colorspace (John Denker).
+ Changed line endings in some of the project files to CRLF, even in the
+ "Unix" tar distributions (Cosmin).
+ Made png_get_int_32 and png_save_int_32 always available (Cosmin).
+ Updated scripts/pngos2.def, scripts/pngw32.def and projects/wince/png32ce.def
+ with the newly exported functions.
+ Eliminated distributions without the "configure" script.
+ Updated INSTALL instructions.
+
+Version 1.2.9beta3 [February 24, 2006]
+ Fixed CRCRLF line endings in contrib/visupng/VisualPng.dsp
+ Made libpng.pc respect EXEC_PREFIX (D. P. Kreil, J. Bowler)
+ Removed reference to pngasmrd.h from Makefile.am
+ Renamed CHANGES to ChangeLog.
+ Renamed LICENSE to COPYING.
+ Renamed ANNOUNCE to NEWS.
+ Created AUTHORS file.
+
+Version 1.2.9beta4 [March 3, 2006]
+ Changed definition of PKGCONFIG from $prefix/lib to $libdir in configure.ac
+ Reverted to filenames LICENSE and ANNOUNCE; removed AUTHORS and COPYING.
+ Removed newline from the end of some error and warning messages.
+ Removed test for sqrt() from configure.ac and configure.
+ Made swap tables in pngtrans.c PNG_CONST (Carlo Bramix).
+ Disabled default iTXt support that was inadvertently enabled in
+ libpng-1.2.9beta1.
+ Added "OS2" to list of systems that don't need underscores, in pnggccrd.c
+ Removed libpng version and date from *.c files.
+
+Version 1.2.9beta5 [March 4, 2006]
+ Removed trailing blanks from source files.
+ Put version and date of latest change in each source file, and changed
+ copyright year accordingly.
+ More cleanup of configure.ac, Makefile.am, and associated scripts.
+ Restored scripts/makefile.elf which was inadvertently deleted.
+
+Version 1.2.9beta6 [March 6, 2006]
+ Fixed typo (RELEASE) in configuration files.
+
+Version 1.2.9beta7 [March 7, 2006]
+ Removed libpng.vers and libpng.sym from libpng12_la_SOURCES in Makefile.am
+ Fixed inconsistent #ifdef's around png_sig_bytes() and png_set_sCAL_s()
+ in png.h.
+ Updated makefile.elf as suggested by debian.
+ Made cosmetic changes to some makefiles, adding LN_SF and other macros.
+ Made some makefiles accept "exec_prefix".
+
+Version 1.2.9beta8 [March 9, 2006]
+ Fixed some "#if defined (..." which should be "#if defined(..."
+ Bug introduced in libpng-1.2.8.
+ Fixed inconsistency in definition of png_default_read_data()
+ Restored blank that was lost from makefile.sggcc "clean" target in beta7.
+ Revised calculation of "current" and "major" for irix in ltmain.sh
+ Changed "mkdir" to "MKDIR_P" in some makefiles.
+ Separated PNG_EXPAND and PNG_EXPAND_tRNS.
+ Added png_set_expand_gray_1_2_4_to_8() and deprecated
+ png_set_gray_1_2_4_to_8() which also expands tRNS to alpha.
+
+Version 1.2.9beta9 [March 10, 2006]
+ Include "config.h" in pngconf.h when available.
+ Added some checks for NULL png_ptr or NULL info_ptr (timeless)
+
+Version 1.2.9beta10 [March 20, 2006]
+ Removed extra CR from contrib/visualpng/VisualPng.dsw (Cosmin)
+ Made pnggccrd.c PIC-compliant (Christian Aichinger).
+ Added makefile.mingw (Wolfgang Glas).
+ Revised pngconf.h MMX checking.
+
+Version 1.2.9beta11 [March 22, 2006]
+ Fixed out-of-order declaration in pngwrite.c that was introduced in beta9
+ Simplified some makefiles by using LIBSO, LIBSOMAJ, and LIBSOVER macros.
+
+Version 1.2.9rc1 [March 31, 2006]
+ Defined PNG_USER_PRIVATEBUILD when including "pngusr.h" (Cosmin).
+ Removed nonsensical assertion check from pngtest.c (Cosmin).
+
+Version 1.2.9 [April 14, 2006]
+ Revised makefile.beos and added "none" selector in ltmain.sh
+
+Version 1.2.10beta1 [April 15, 2006]
+ Renamed "config.h" to "png_conf.h" and revised Makefile.am to add
+ -DPNG_BUILDING_LIBPNG to compile directive, and modified pngconf.h
+ to include png_conf.h only when PNG_BUILDING_LIBPNG is defined.
+
+Version 1.2.10beta2 [April 15, 2006]
+ Manually updated Makefile.in and configure. Changed png_conf.h.in
+ back to config.h.
+
+Version 1.2.10beta3 [April 15, 2006]
+ Change png_conf.h back to config.h in pngconf.h.
+
+Version 1.2.10beta4 [April 16, 2006]
+ Change PNG_BUILDING_LIBPNG to PNG_CONFIGURE_LIBPNG in config/Makefile*.
+
+Version 1.2.10beta5 [April 16, 2006]
+ Added a configure check for compiling assembler code in pnggccrd.c
+
+Version 1.2.10beta6 [April 17, 2006]
+ Revised the configure check for pnggccrd.c
+ Moved -DPNG_CONFIGURE_LIBPNG into @LIBPNG_DEFINES@
+ Added @LIBPNG_DEFINES@ to arguments when building libpng.sym
+
+Version 1.2.10beta7 [April 18, 2006]
+ Change "exec_prefix=$prefix" to "exec_prefix=$(prefix)" in makefiles.
+
+Version 1.2.10rc1 [April 19, 2006]
+ Ensure pngconf.h doesn't define both PNG_USE_PNGGCCRD and PNG_USE_PNGVCRD
+ Fixed "LN_FS" typo in makefile.sco and makefile.solaris.
+
+Version 1.2.10rc2 [April 20, 2006]
+ Added a backslash between -DPNG_CONFIGURE_LIBPNG and -DPNG_NO_ASSEMBLER_CODE
+ in configure.ac and configure
+ Made the configure warning about versioned symbols less arrogant.
+
+Version 1.2.10rc3 [April 21, 2006]
+ Added a note in libpng.txt that png_set_sig_bytes(8) can be used when
+ writing an embedded PNG without the 8-byte signature.
+ Revised makefiles and configure to avoid making links to libpng.so.*
+
+Version 1.2.10 [April 23, 2006]
+ Reverted configure to "rc2" state.
+
+Version 1.2.11beta1 [May 31, 2006]
+ scripts/libpng.pc.in contained "configure" style version info and would
+ not work with makefiles.
+ The shared-library makefiles were linking to libpng.so.0 instead of
+ libpng.so.3 compatibility as the library.
+
+Version 1.2.11beta2 [June 2, 2006]
+ Increased sprintf buffer from 50 to 52 chars in pngrutil.c to avoid
+ buffer overflow.
+ Fixed bug in example.c (png_set_palette_rgb -> png_set_palette_to_rgb)
+
+Version 1.2.11beta3 [June 5, 2006]
+ Prepended "#! /bin/sh" to ltmail.sh and contrib/pngminus/*.sh (Cosmin).
+ Removed the accidental leftover Makefile.in~ (Cosmin).
+ Avoided potential buffer overflow and optimized buffer in
+ png_write_sCAL(), png_write_sCAL_s() (Cosmin).
+ Removed the include directories and libraries from CFLAGS and LDFLAGS
+ in scripts/makefile.gcc (Nelson A. de Oliveira, Cosmin).
+
+Version 1.2.11beta4 [June 6, 2006]
+ Allow zero-length IDAT chunks after the entire zlib datastream, but not
+ after another intervening chunk type.
+
+Version 1.0.19rc1, 1.2.11rc1 [June 13, 2006]
+ Deleted extraneous square brackets from [config.h] in configure.ac
+
+Version 1.0.19rc2, 1.2.11rc2 [June 14, 2006]
+ Added prototypes for PNG_INCH_CONVERSIONS functions to png.h
+ Revised INSTALL and autogen.sh
+ Fixed typo in several makefiles (-W1 should be -Wl)
+ Added typedef for png_int_32 and png_uint_32 on 64-bit systems.
+
+Version 1.0.19rc3, 1.2.11rc3 [June 15, 2006]
+ Removed the new typedefs for 64-bit systems (delay until version 1.4.0)
+ Added one zero element to png_gamma_shift[] array in pngrtran.c to avoid
+ reading out of bounds.
+
+Version 1.0.19rc4, 1.2.11rc4 [June 15, 2006]
+ Really removed the new typedefs for 64-bit systems.
+
+Version 1.0.19rc5, 1.2.11rc5 [June 22, 2006]
+ Removed png_sig_bytes entry from scripts/pngw32.def
+
+Version 1.0.19, 1.2.11 [June 26, 2006]
+ None.
+
+Version 1.0.20, 1.2.12 [June 27, 2006]
+ Really increased sprintf buffer from 50 to 52 chars in pngrutil.c to avoid
+ buffer overflow.
+
+Version 1.2.13beta1 [October 2, 2006]
+ Removed AC_FUNC_MALLOC from configure.ac
+ Work around Intel-Mac compiler bug by setting PNG_NO_MMX_CODE in pngconf.h
+ Change "logical" to "bitwise" throughout documentation.
+ Detect and fix attempt to write wrong iCCP profile length (CVE-2006-7244)
+
+Version 1.0.21, 1.2.13 [November 14, 2006]
+ Fix potential buffer overflow in sPLT chunk handler.
+ Fix Makefile.am to not try to link to noexistent files.
+ Check all exported functions for NULL png_ptr.
+
+Version 1.2.14beta1 [November 17, 2006]
+ Relocated three misplaced tests for NULL png_ptr.
+ Built Makefile.in with automake-1.9.6 instead of 1.9.2.
+ Build configure with autoconf-2.60 instead of 2.59
+
+Version 1.2.14beta2 [November 17, 2006]
+ Added some typecasts in png_zalloc().
+
+Version 1.2.14rc1 [November 20, 2006]
+ Changed "strtod" to "png_strtod" in pngrutil.c
+
+Version 1.0.22, 1.2.14 [November 27, 2006]
+ Added missing "$(srcdir)" in Makefile.am and Makefile.in
+
+Version 1.2.15beta1 [December 3, 2006]
+ Generated configure with autoconf-2.61 instead of 2.60
+ Revised configure.ac to update libpng.pc and libpng-config.
+
+Version 1.2.15beta2 [December 3, 2006]
+ Always export MMX asm functions, just stubs if not building pnggccrd.c
+
+Version 1.2.15beta3 [December 4, 2006]
+ Add "png_bytep" typecast to profile while calculating length in pngwutil.c
+
+Version 1.2.15beta4 [December 7, 2006]
+ Added scripts/CMakeLists.txt
+ Changed PNG_NO_ASSEMBLER_CODE to PNG_NO_MMX_CODE in scripts, like 1.4.0beta
+
+Version 1.2.15beta5 [December 7, 2006]
+ Changed some instances of PNG_ASSEMBLER_* to PNG_MMX_* in pnggccrd.c
+ Revised scripts/CMakeLists.txt
+
+Version 1.2.15beta6 [December 13, 2006]
+ Revised scripts/CMakeLists.txt and configure.ac
+
+Version 1.2.15rc1 [December 18, 2006]
+ Revised scripts/CMakeLists.txt
+
+Version 1.2.15rc2 [December 21, 2006]
+ Added conditional #undef jmpbuf in pngtest.c to undo #define in AIX headers.
+ Added scripts/makefile.nommx
+
+Version 1.2.15rc3 [December 25, 2006]
+ Fixed shared library numbering error that was introduced in 1.2.15beta6.
+
+Version 1.2.15rc4 [December 27, 2006]
+ Fixed handling of rgb_to_gray when png_ptr->color.gray isn't set.
+
+Version 1.2.15rc5 [December 31, 2006]
+ Revised handling of rgb_to_gray.
+
+Version 1.2.15 [January 5, 2007]
+ Added some (unsigned long) typecasts in pngtest.c to avoid printing errors.
+
+Version 1.2.16beta1 [January 6, 2007]
+ Fix bugs in makefile.nommx
+
+Version 1.2.16beta2 [January 16, 2007]
+ Revised scripts/CMakeLists.txt
+
+Version 1.2.16 [January 31, 2007]
+ No changes.
+
+Version 1.2.17beta1 [March 6, 2007]
+ Revised scripts/CMakeLists.txt to install both shared and static libraries.
+ Deleted a redundant line from pngset.c.
+
+Version 1.2.17beta2 [April 26, 2007]
+ Relocated misplaced test for png_ptr == NULL in pngpread.c
+ Change "==" to "&" for testing PNG_RGB_TO_GRAY_ERR & PNG_RGB_TO_GRAY_WARN
+ flags.
+ Changed remaining instances of PNG_ASSEMBLER_* to PNG_MMX_*
+ Added pngerror() when write_IHDR fails in deflateInit2().
+ Added "const" to some array declarations.
+ Mention examples of libpng usage in the libpng*.txt and libpng.3 documents.
+
+Version 1.2.17rc1 [May 4, 2007]
+ No changes.
+
+Version 1.2.17rc2 [May 8, 2007]
+ Moved several PNG_HAVE_* macros out of PNG_INTERNAL because applications
+ calling set_unknown_chunk_location() need them.
+ Changed transformation flag from PNG_EXPAND_tRNS to PNG_EXPAND in
+ png_set_expand_gray_1_2_4_to_8().
+ Added png_ptr->unknown_chunk to hold working unknown chunk data, so it
+ can be free'ed in case of error. Revised unknown chunk handling in
+ pngrutil.c and pngpread.c to use this structure.
+
+Version 1.2.17rc3 [May 8, 2007]
+ Revised symbol-handling in configure script.
+
+Version 1.2.17rc4 [May 10, 2007]
+ Revised unknown chunk handling to avoid storing unknown critical chunks.
+
+Version 1.0.25 [May 15, 2007]
+Version 1.2.17 [May 15, 2007]
+ Added "png_ptr->num_trans=0" before error return in png_handle_tRNS,
+ to eliminate a vulnerability (CVE-2007-2445, CERT VU#684664)
+
+Version 1.0.26 [May 15, 2007]
+Version 1.2.18 [May 15, 2007]
+ Reverted the libpng-1.2.17rc3 change to symbol-handling in configure script
+
+Version 1.2.19beta1 [May 18, 2007]
+ Changed "const static" to "static PNG_CONST" everywhere, mostly undoing
+ change of libpng-1.2.17beta2. Changed other "const" to "PNG_CONST"
+ Changed some handling of unused parameters, to avoid compiler warnings.
+ "if (unused == NULL) return;" becomes "unused = unused".
+
+Version 1.2.19beta2 [May 18, 2007]
+ Only use the valid bits of tRNS value in png_do_expand() (Brian Cartier)
+
+Version 1.2.19beta3 [May 19, 2007]
+ Add some "png_byte" typecasts in png_check_keyword() and write new_key
+ instead of key in zTXt chunk (Kevin Ryde).
+
+Version 1.2.19beta4 [May 21, 2007]
+ Add png_snprintf() function and use it in place of sprint() for improved
+ defense against buffer overflows.
+
+Version 1.2.19beta5 [May 21, 2007]
+ Fixed png_handle_tRNS() to only use the valid bits of tRNS value.
+ Changed handling of more unused parameters, to avoid compiler warnings.
+ Removed some PNG_CONST in pngwutil.c to avoid compiler warnings.
+
+Version 1.2.19beta6 [May 22, 2007]
+ Added some #ifdef PNG_MMX_CODE_SUPPORTED where needed in pngvcrd.c
+ Added a special "_MSC_VER" case that defines png_snprintf to _snprintf
+
+Version 1.2.19beta7 [May 22, 2007]
+ Squelched png_squelch_warnings() in pnggccrd.c and added
+ an #ifdef PNG_MMX_CODE_SUPPORTED block around the declarations that caused
+ the warnings that png_squelch_warnings was squelching.
+
+Version 1.2.19beta8 [May 22, 2007]
+ Removed __MMX__ from test in pngconf.h.
+
+Version 1.2.19beta9 [May 23, 2007]
+ Made png_squelch_warnings() available via PNG_SQUELCH_WARNINGS macro.
+ Revised png_squelch_warnings() so it might work.
+ Updated makefile.sgcc and makefile.solaris; added makefile.solaris-x86.
+
+Version 1.2.19beta10 [May 24, 2007]
+ Resquelched png_squelch_warnings(), use "__attribute__((used))" instead.
+
+Version 1.4.0beta1 [April 20, 2006]
+ Enabled iTXt support (changes png_struct, thus requires so-number change).
+ Cleaned up PNG_ASSEMBLER_CODE_SUPPORTED vs PNG_MMX_CODE_SUPPORTED
+ Eliminated PNG_1_0_X and PNG_1_2_X macros.
+ Removed deprecated functions png_read_init, png_write_init, png_info_init,
+ png_permit_empty_plte, png_set_gray_1_2_4_to_8, png_check_sig, and
+ removed the deprecated macro PNG_MAX_UINT.
+ Moved "PNG_INTERNAL" parts of png.h and pngconf.h into pngintrn.h
+ Removed many WIN32_WCE #ifdefs (Cosmin).
+ Reduced dependency on C-runtime library when on Windows (Simon-Pierre)
+ Replaced sprintf() with png_sprintf() (Simon-Pierre)
+
+Version 1.4.0beta2 [April 20, 2006]
+ Revised makefiles and configure to avoid making links to libpng.so.*
+ Moved some leftover MMX-related defines from pngconf.h to pngintrn.h
+ Updated scripts/pngos2.def, pngw32.def, and projects/wince/png32ce.def
+
+Version 1.4.0beta3 [May 10, 2006]
+ Updated scripts/pngw32.def to comment out MMX functions.
+ Added PNG_NO_GET_INT_32 and PNG_NO_SAVE_INT_32 macros.
+ Scripts/libpng.pc.in contained "configure" style version info and would
+ not work with makefiles.
+ Revised pngconf.h and added pngconf.h.in, so makefiles and configure can
+ pass defines to libpng and applications.
+
+Version 1.4.0beta4 [May 11, 2006]
+ Revised configure.ac, Makefile.am, and many of the makefiles to write
+ their defines in pngconf.h.
+
+Version 1.4.0beta5 [May 15, 2006]
+ Added a missing semicolon in Makefile.am and Makefile.in
+ Deleted extraneous square brackets from configure.ac
+
+Version 1.4.0beta6 [June 2, 2006]
+ Increased sprintf buffer from 50 to 52 chars in pngrutil.c to avoid
+ buffer overflow.
+ Changed sonum from 0 to 1.
+ Removed unused prototype for png_check_sig() from png.h
+
+Version 1.4.0beta7 [June 16, 2006]
+ Exported png_write_sig (Cosmin).
+ Optimized buffer in png_handle_cHRM() (Cosmin).
+ Set pHYs = 2835 x 2835 pixels per meter, and added
+ sCAL = 0.352778e-3 x 0.352778e-3 meters, in pngtest.png (Cosmin).
+ Added png_set_benign_errors(), png_benign_error(), png_chunk_benign_error().
+ Added typedef for png_int_32 and png_uint_32 on 64-bit systems.
+ Added "(unsigned long)" typecast on png_uint_32 variables in printf lists.
+
+Version 1.4.0beta8 [June 22, 2006]
+ Added demonstration of user chunk support in pngtest.c, to support the
+ public sTER chunk and a private vpAg chunk.
+
+Version 1.4.0beta9 [July 3, 2006]
+ Removed ordinals from scripts/pngw32.def and removed png_info_int and
+ png_set_gray_1_2_4_to_8 entries.
+ Inline call of png_get_uint_32() in png_get_uint_31().
+ Use png_get_uint_31() to get vpAg width and height in pngtest.c
+ Removed WINCE and Netware projects.
+ Removed standalone Y2KINFO file.
+
+Version 1.4.0beta10 [July 12, 2006]
+ Eliminated automatic copy of pngconf.h to pngconf.h.in from configure and
+ some makefiles, because it was not working reliably. Instead, distribute
+ pngconf.h.in along with pngconf.h and cause configure and some of the
+ makefiles to update pngconf.h from pngconf.h.in.
+ Added pngconf.h to DEPENDENCIES in Makefile.am
+
+Version 1.4.0beta11 [August 19, 2006]
+ Removed AC_FUNC_MALLOC from configure.ac.
+ Added a warning when writing iCCP profile with mismatched profile length.
+ Patched pnggccrd.c to assemble on x86_64 platforms.
+ Moved chunk header reading into a separate function png_read_chunk_header()
+ in pngrutil.c. The chunk header (len+sig) is now serialized in a single
+ operation (Cosmin).
+ Implemented support for I/O states. Added png_ptr member io_state, and
+ functions png_get_io_chunk_name() and png_get_io_state() in pngget.c
+ (Cosmin).
+ Added png_get_io_chunk_name and png_get_io_state to scripts/*.def (Cosmin).
+ Renamed scripts/pngw32.* to scripts/pngwin.* (Cosmin).
+ Removed the include directories and libraries from CFLAGS and LDFLAGS
+ in scripts/makefile.gcc (Cosmin).
+ Used png_save_uint_32() to set vpAg width and height in pngtest.c (Cosmin).
+ Cast to proper type when getting/setting vpAg units in pngtest.c (Cosmin).
+ Added pngintrn.h to the Visual C++ projects (Cosmin).
+ Removed scripts/list (Cosmin).
+ Updated copyright year in scripts/pngwin.def (Cosmin).
+ Removed PNG_TYPECAST_NULL and used standard NULL consistently (Cosmin).
+ Disallowed the user to redefine png_size_t, and enforced a consistent use
+ of png_size_t across libpng (Cosmin).
+ Changed the type of png_ptr->rowbytes, PNG_ROWBYTES() and friends
+ to png_size_t (Cosmin).
+ Removed png_convert_size() and replaced png_sizeof with sizeof (Cosmin).
+ Removed some unnecessary type casts (Cosmin).
+ Changed prototype of png_get_compression_buffer_size() and
+ png_set_compression_buffer_size() to work with png_size_t instead of
+ png_uint_32 (Cosmin).
+ Removed png_memcpy_check() and png_memset_check() (Cosmin).
+ Fixed a typo (png_byte --> png_bytep) in libpng.3 and libpng.txt (Cosmin).
+ Clarified that png_zalloc() does not clear the allocated memory,
+ and png_zalloc() and png_zfree() cannot be PNGAPI (Cosmin).
+ Renamed png_mem_size_t to png_alloc_size_t, fixed its definition in
+ pngconf.h, and used it in all memory allocation functions (Cosmin).
+ Renamed pngintrn.h to pngpriv.h, added a comment at the top of the file
+ mentioning that the symbols declared in that file are private, and
+ updated the scripts and the Visual C++ projects accordingly (Cosmin).
+ Removed circular references between pngconf.h and pngconf.h.in in
+ scripts/makefile.vc*win32 (Cosmin).
+ Removing trailing '.' from the warning and error messages (Cosmin).
+ Added pngdefs.h that is built by makefile or configure, instead of
+ pngconf.h.in (Glenn).
+ Detect and fix attempt to write wrong iCCP profile length.
+
+Version 1.4.0beta12 [October 19, 2006]
+ Changed "logical" to "bitwise" in the documentation.
+ Work around Intel-Mac compiler bug by setting PNG_NO_MMX_CODE in pngconf.h
+ Add a typecast to stifle compiler warning in pngrutil.c
+
+Version 1.4.0beta13 [November 10, 2006]
+ Fix potential buffer overflow in sPLT chunk handler.
+ Fix Makefile.am to not try to link to noexistent files.
+
+Version 1.4.0beta14 [November 15, 2006]
+ Check all exported functions for NULL png_ptr.
+
+Version 1.4.0beta15 [November 17, 2006]
+ Relocated two misplaced tests for NULL png_ptr.
+ Built Makefile.in with automake-1.9.6 instead of 1.9.2.
+ Build configure with autoconf-2.60 instead of 2.59
+ Add "install: all" in Makefile.am so "configure; make install" will work.
+
+Version 1.4.0beta16 [November 17, 2006]
+ Added a typecast in png_zalloc().
+
+Version 1.4.0beta17 [December 4, 2006]
+ Changed "new_key[79] = '\0';" to "(*new_key)[79] = '\0';" in pngwutil.c
+ Add "png_bytep" typecast to profile while calculating length in pngwutil.c
+
+Version 1.4.0beta18 [December 7, 2006]
+ Added scripts/CMakeLists.txt
+
+Version 1.4.0beta19 [May 16, 2007]
+ Revised scripts/CMakeLists.txt
+ Rebuilt configure and Makefile.in with newer tools.
+ Added conditional #undef jmpbuf in pngtest.c to undo #define in AIX headers.
+ Added scripts/makefile.nommx
+
+Version 1.4.0beta20 [July 9, 2008]
+ Moved several PNG_HAVE_* macros from pngpriv.h to png.h because applications
+ calling set_unknown_chunk_location() need them.
+ Moved several macro definitions from pngpriv.h to pngconf.h
+ Merge with changes to the 1.2.X branch, as of 1.2.30beta04.
+ Deleted all use of the MMX assembler code and Intel-licensed optimizations.
+ Revised makefile.mingw
+
+Version 1.4.0beta21 [July 21, 2008]
+ Moved local array "chunkdata" from pngrutil.c to the png_struct, so
+ it will be freed by png_read_destroy() in case of a read error (Kurt
+ Christensen).
+
+Version 1.4.0beta22 [July 21, 2008]
+ Change "purpose" and "buffer" to png_ptr->chunkdata to avoid memory leaking.
+
+Version 1.4.0beta23 [July 22, 2008]
+ Change "chunkdata = NULL" to "png_ptr->chunkdata = NULL" several places in
+ png_decompress_chunk().
+
+Version 1.4.0beta24 [July 25, 2008]
+ Change all remaining "chunkdata" to "png_ptr->chunkdata" in
+ png_decompress_chunk(), and remove "chunkdata" from parameter list.
+ Put a call to png_check_chunk_name() in png_read_chunk_header().
+ Revised png_check_chunk_name() to reject a name with a lowercase 3rd byte.
+ Removed two calls to png_check_chunk_name() occurring later in the process.
+ Define PNG_NO_ERROR_NUMBERS by default in pngconf.h
+
+Version 1.4.0beta25 [July 30, 2008]
+ Added a call to png_check_chunk_name() in pngpread.c
+ Reverted png_check_chunk_name() to accept a name with a lowercase 3rd byte.
+ Added png_push_have_buffer() function to pngpread.c
+ Eliminated PNG_BIG_ENDIAN_SUPPORTED and associated png_get_* macros.
+ Made inline expansion of png_get_*() optional with PNG_USE_READ_MACROS.
+ Eliminated all PNG_USELESS_TESTS and PNG_CORRECT_PALETTE_SUPPORTED code.
+ Synced contrib directory and configure files with libpng-1.2.30beta06.
+ Eliminated no-longer-used pngdefs.h (but it's still built in the makefiles)
+ Relocated a misplaced "#endif /* PNG_NO_WRITE_FILTER */" in pngwutil.c
+
+Version 1.4.0beta26 [August 4, 2008]
+ Removed png_push_have_buffer() function in pngpread.c. It increased the
+ compiled library size slightly.
+ Changed "-Wall" to "-W -Wall" in the CFLAGS in all makefiles (Cosmin Truta)
+ Declared png_ptr "volatile" in pngread.c and pngwrite.c to avoid warnings.
+ Updated contrib/visupng/cexcept.h to version 2.0.1
+ Added PNG_LITERAL_CHARACTER macros for #, [, and ].
+
+Version 1.4.0beta27 [August 5, 2008]
+ Revised usage of PNG_LITERAL_SHARP in pngerror.c.
+ Moved newline character from individual png_debug messages into the
+ png_debug macros.
+ Allow user to #define their own png_debug, png_debug1, and png_debug2.
+
+Version 1.4.0beta28 [August 5, 2008]
+ Revised usage of PNG_LITERAL_SHARP in pngerror.c.
+ Added PNG_STRING_NEWLINE macro
+
+Version 1.4.0beta29 [August 9, 2008]
+ Revised usage of PNG_STRING_NEWLINE to work on non-ISO compilers.
+ Added PNG_STRING_COPYRIGHT macro.
+ Added non-ISO versions of png_debug macros.
+
+Version 1.4.0beta30 [August 14, 2008]
+ Added premultiplied alpha feature (Volker Wiendl).
+
+Version 1.4.0beta31 [August 18, 2008]
+ Moved png_set_premultiply_alpha from pngtrans.c to pngrtran.c
+ Removed extra crc check at the end of png_handle_cHRM(). Bug introduced
+ in libpng-1.4.0beta20.
+
+Version 1.4.0beta32 [August 19, 2008]
+ Added PNG_WRITE_FLUSH_SUPPORTED block around new png_flush() call.
+ Revised PNG_NO_STDIO version of png_write_flush()
+
+Version 1.4.0beta33 [August 20, 2008]
+ Added png_get|set_chunk_cache_max() to limit the total number of sPLT,
+ text, and unknown chunks that can be stored.
+
+Version 1.4.0beta34 [September 6, 2008]
+ Shortened tIME_string to 29 bytes in pngtest.c
+ Fixed off-by-one error introduced in png_push_read_zTXt() function in
+ libpng-1.2.30beta04/pngpread.c (Harald van Dijk)
+
+Version 1.4.0beta35 [October 6, 2008]
+ Changed "trans_values" to "trans_color".
+ Changed so-number from 0 to 14. Some OS do not like 0.
+ Revised makefile.darwin to fix shared library numbering.
+ Change png_set_gray_1_2_4_to_8() to png_set_expand_gray_1_2_4_to_8()
+ in example.c (debian bug report)
+
+Version 1.4.0beta36 [October 25, 2008]
+ Sync with tEXt vulnerability fix in libpng-1.2.33rc02.
+
+Version 1.4.0beta37 [November 13, 2008]
+ Added png_check_cHRM in png.c and moved checking from pngget.c, pngrutil.c,
+ and pngwrite.c
+
+Version 1.4.0beta38 [November 22, 2008]
+ Added check for zero-area RGB cHRM triangle in png_check_cHRM() and
+ png_check_cHRM_fixed().
+
+Version 1.4.0beta39 [November 23, 2008]
+ Revised png_warning() to write its message on standard output by default
+ when warning_fn is NULL.
+
+Version 1.4.0beta40 [November 24, 2008]
+ Eliminated png_check_cHRM(). Instead, always use png_check_cHRM_fixed().
+ In png_check_cHRM_fixed(), ensure white_y is > 0, and removed redundant
+ check for all-zero coordinates that is detected by the triangle check.
+
+Version 1.4.0beta41 [November 26, 2008]
+ Fixed string vs pointer-to-string error in png_check_keyword().
+ Rearranged test expressions in png_check_cHRM_fixed() to avoid internal
+ overflows.
+ Added PNG_NO_CHECK_cHRM conditional.
+
+Version 1.4.0beta42, 43 [December 1, 2008]
+ Merge png_debug with version 1.2.34beta04.
+
+Version 1.4.0beta44 [December 6, 2008]
+ Removed redundant check for key==NULL before calling png_check_keyword()
+ to ensure that new_key gets initialized and removed extra warning
+ (Merge with version 1.2.34beta05 -- Arvan Pritchard).
+
+Version 1.4.0beta45 [December 9, 2008]
+ In png_write_png(), respect the placement of the filler bytes in an earlier
+ call to png_set_filler() (Jim Barry).
+
+Version 1.4.0beta46 [December 10, 2008]
+ Undid previous change and added PNG_TRANSFORM_STRIP_FILLER_BEFORE and
+ PNG_TRANSFORM_STRIP_FILLER_AFTER conditionals and deprecated
+ PNG_TRANSFORM_STRIP_FILLER (Jim Barry).
+
+Version 1.4.0beta47 [December 15, 2008]
+ Support for dithering was disabled by default, because it has never
+ been well tested and doesn't work very well. The code has not
+ been removed, however, and can be enabled by building libpng with
+ PNG_READ_DITHER_SUPPORTED defined.
+
+Version 1.4.0beta48 [February 14, 2009]
+ Added new exported function png_calloc().
+ Combined several instances of png_malloc(); png_memset() into png_calloc().
+ Removed prototype for png_freeptr() that was added in libpng-1.4.0beta24
+ but was never defined.
+
+Version 1.4.0beta49 [February 28, 2009]
+ Added png_fileno() macro to pngconf.h, used in pngwio.c
+ Corrected order of #ifdef's in png_debug definition in png.h
+ Fixed bug introduced in libpng-1.4.0beta48 with the memset arguments
+ for pcal_params.
+ Fixed order of #ifdef directives in the png_debug defines in png.h
+ (bug introduced in libpng-1.2.34/1.4.0beta29).
+ Revised comments in png_set_read_fn() and png_set_write_fn().
+
+Version 1.4.0beta50 [March 18, 2009]
+ Use png_calloc() instead of png_malloc() to allocate big_row_buf when
+ reading an interlaced file, to avoid a possible UMR.
+ Undid revision of PNG_NO_STDIO version of png_write_flush(). Users
+ having trouble with fflush() can build with PNG_NO_WRITE_FLUSH defined
+ or supply their own flush_fn() replacement.
+ Revised libpng*.txt and png.h documentation about use of png_write_flush()
+ and png_set_write_fn().
+ Removed fflush() from pngtest.c.
+ Added "#define PNG_NO_WRITE_FLUSH" to contrib/pngminim/encoder/pngusr.h
+
+Version 1.4.0beta51 [March 21, 2009]
+ Removed new png_fileno() macro from pngconf.h .
+
+Version 1.4.0beta52 [March 27, 2009]
+ Relocated png_do_chop() ahead of building gamma tables in pngrtran.c
+ This avoids building 16-bit gamma tables unnecessarily.
+ Removed fflush() from pngtest.c.
+ Added "#define PNG_NO_WRITE_FLUSH" to contrib/pngminim/encoder/pngusr.h
+ Added a section on differences between 1.0.x and 1.2.x to libpng.3/libpng.txt
+
+Version 1.4.0beta53 [April 1, 2009]
+ Removed some remaining MMX macros from pngpriv.h
+ Fixed potential memory leak of "new_name" in png_write_iCCP() (Ralph Giles)
+
+Version 1.4.0beta54 [April 13, 2009]
+ Added "ifndef PNG_SKIP_SETJMP_CHECK" block in pngconf.h to allow
+ application code writers to bypass the check for multiple inclusion
+ of setjmp.h when they know that it is safe to ignore the situation.
+ Eliminated internal use of setjmp() in pngread.c and pngwrite.c
+ Reordered ancillary chunks in pngtest.png to be the same as what
+ pngtest now produces, and made some cosmetic changes to pngtest output.
+ Eliminated deprecated png_read_init_3() and png_write_init_3() functions.
+
+Version 1.4.0beta55 [April 15, 2009]
+ Simplified error handling in pngread.c and pngwrite.c by putting
+ the new png_read_cleanup() and png_write_cleanup() functions inline.
+
+Version 1.4.0beta56 [April 25, 2009]
+ Renamed "user_chunk_data" to "my_user_chunk_data" in pngtest.c to suppress
+ "shadowed declaration" warning from gcc-4.3.3.
+ Renamed "gamma" to "png_gamma" in pngset.c to avoid "shadowed declaration"
+ warning about a global "gamma" variable in math.h on some platforms.
+
+Version 1.4.0beta57 [May 2, 2009]
+ Removed prototype for png_freeptr() that was added in libpng-1.4.0beta24
+ but was never defined (again).
+ Rebuilt configure scripts with autoconf-2.63 instead of 2.62
+ Removed pngprefs.h and MMX from makefiles
+
+Version 1.4.0beta58 [May 14, 2009]
+ Changed pngw32.def to pngwin.def in makefile.mingw (typo was introduced
+ in beta57).
+ Clarified usage of sig_bit versus sig_bit_p in example.c (Vincent Torri)
+
+Version 1.4.0beta59 [May 15, 2009]
+ Reformated sources in libpng style (3-space intentation, comment format)
+ Fixed typo in libpng docs (PNG_FILTER_AVE should be PNG_FILTER_AVG)
+ Added sections about the git repository and our coding style to the
+ documentation
+ Relocated misplaced #endif in pngwrite.c, sCAL chunk handler.
+
+Version 1.4.0beta60 [May 19, 2009]
+ Conditionally compile png_read_finish_row() which is not used by
+ progressive readers.
+ Added contrib/pngminim/preader to demonstrate building minimal progressive
+ decoder, based on contrib/gregbook with embedded libpng and zlib.
+
+Version 1.4.0beta61 [May 20, 2009]
+ In contrib/pngminim/*, renamed "makefile.std" to "makefile", since there
+ is only one makefile in those directories, and revised the README files
+ accordingly.
+ More reformatting of comments, mostly to capitalize sentences.
+
+Version 1.4.0beta62 [June 2, 2009]
+ Added "#define PNG_NO_WRITE_SWAP" to contrib/pngminim/encoder/pngusr.h
+ and "define PNG_NO_READ_SWAP" to decoder/pngusr.h and preader/pngusr.h
+ Reformatted several remaining "else statement" into two lines.
+ Added a section to the libpng documentation about using png_get_io_ptr()
+ in configure scripts to detect the presence of libpng.
+
+Version 1.4.0beta63 [June 15, 2009]
+ Revised libpng*.txt and libpng.3 to mention calling png_set_IHDR()
+ multiple times and to specify the sample order in the tRNS chunk,
+ because the ISO PNG specification has a typo in the tRNS table.
+ Changed several PNG_UNKNOWN_CHUNK_SUPPORTED to
+ PNG_HANDLE_AS_UNKNOWN_SUPPORTED, to make the png_set_keep mechanism
+ available for ignoring known chunks even when not saving unknown chunks.
+ Adopted preference for consistent use of "#ifdef" and "#ifndef" versus
+ "#if defined()" and "if !defined()" where possible.
+
+Version 1.4.0beta64 [June 24, 2009]
+ Eliminated PNG_LEGACY_SUPPORTED code.
+ Moved the various unknown chunk macro definitions outside of the
+ PNG_READ|WRITE_ANCILLARY_CHUNK_SUPPORTED blocks.
+
+Version 1.4.0beta65 [June 26, 2009]
+ Added a reference to the libpng license in each file.
+
+Version 1.4.0beta66 [June 27, 2009]
+ Refer to the libpng license instead of the libpng license in each file.
+
+Version 1.4.0beta67 [July 6, 2009]
+ Relocated INVERT_ALPHA within png_read_png() and png_write_png().
+ Added high-level API transform PNG_TRANSFORM_GRAY_TO_RGB.
+ Added an "xcode" project to the projects directory (Alam Arias).
+
+Version 1.4.0beta68 [July 19, 2009]
+ Avoid some tests in filter selection in pngwutil.c
+
+Version 1.4.0beta69 [July 25, 2009]
+ Simplified the new filter-selection test. This runs faster in the
+ common "PNG_ALL_FILTERS" and PNG_FILTER_NONE cases.
+ Removed extraneous declaration from the new call to png_read_gray_to_rgb()
+ (bug introduced in libpng-1.4.0beta67).
+ Fixed up xcode project (Alam Arias)
+ Added a prototype for png_64bit_product() in png.c
+
+Version 1.4.0beta70 [July 27, 2009]
+ Avoid a possible NULL dereference in debug build, in png_set_text_2().
+ (bug introduced in libpng-0.95, discovered by Evan Rouault)
+
+Version 1.4.0beta71 [July 29, 2009]
+ Rebuilt configure scripts with autoconf-2.64.
+
+Version 1.4.0beta72 [August 1, 2009]
+ Replaced *.tar.lzma with *.tar.xz in distribution. Get the xz codec
+ from <http://tukaani.org/xz>.
+
+Version 1.4.0beta73 [August 1, 2009]
+ Reject attempt to write iCCP chunk with negative embedded profile length
+ (JD Chen) (CVE-2009-5063).
+
+Version 1.4.0beta74 [August 8, 2009]
+ Changed png_ptr and info_ptr member "trans" to "trans_alpha".
+
+Version 1.4.0beta75 [August 21, 2009]
+ Removed an extra png_debug() recently added to png_write_find_filter().
+ Fixed incorrect #ifdef in pngset.c regarding unknown chunk support.
+
+Version 1.4.0beta76 [August 22, 2009]
+ Moved an incorrectly located test in png_read_row() in pngread.c
+
+Version 1.4.0beta77 [August 27, 2009]
+ Removed lpXYZ.tar.bz2 (with CRLF), KNOWNBUG, libpng-x.y.z-KNOWNBUG.txt,
+ and the "noconfig" files from the distribution.
+ Moved CMakeLists.txt from scripts into the main libpng directory.
+ Various bugfixes and improvements to CMakeLists.txt (Philip Lowman)
+
+Version 1.4.0beta78 [August 31, 2009]
+ Converted all PNG_NO_* tests to PNG_*_SUPPORTED everywhere except pngconf.h
+ Eliminated PNG_NO_FREE_ME and PNG_FREE_ME_SUPPORTED macros.
+ Use png_malloc plus a loop instead of png_calloc() to initialize
+ row_pointers in png_read_png().
+
+Version 1.4.0beta79 [September 1, 2009]
+ Eliminated PNG_GLOBAL_ARRAYS and PNG_LOCAL_ARRAYS; always use local arrays.
+ Eliminated PNG_CALLOC_SUPPORTED macro and always provide png_calloc().
+
+Version 1.4.0beta80 [September 17, 2009]
+ Removed scripts/libpng.icc
+ Changed typecast of filler from png_byte to png_uint_16 in png_set_filler().
+ (Dennis Gustafsson)
+ Fixed typo introduced in beta78 in pngtest.c ("#if def " should be "#ifdef ")
+
+Version 1.4.0beta81 [September 23, 2009]
+ Eliminated unused PNG_FLAG_FREE_* defines from pngpriv.h
+ Expanded TAB characters in pngrtran.c
+ Removed PNG_CONST from all "PNG_CONST PNG_CHNK" declarations to avoid
+ compiler complaints about doubly declaring things "const".
+ Changed all "#if [!]defined(X)" to "if[n]def X" where possible.
+ Eliminated unused png_ptr->row_buf_size
+
+Version 1.4.0beta82 [September 25, 2009]
+ Moved redundant IHDR checking into new png_check_IHDR() in png.c
+ and report all errors found in the IHDR data.
+ Eliminated useless call to png_check_cHRM() from pngset.c
+
+Version 1.4.0beta83 [September 25, 2009]
+ Revised png_check_IHDR() to eliminate bogus complaint about filter_type.
+
+Version 1.4.0beta84 [September 30, 2009]
+ Fixed some inconsistent indentation in pngconf.h
+ Revised png_check_IHDR() to add a test for width variable less than 32-bit.
+
+Version 1.4.0beta85 [October 1, 2009]
+ Revised png_check_IHDR() again, to check info_ptr members instead of
+ the contents of the returned parameters.
+
+Version 1.4.0beta86 [October 9, 2009]
+ Updated the "xcode" project (Alam Arias).
+ Eliminated a shadowed declaration of "pp" in png_handle_sPLT().
+
+Version 1.4.0rc01 [October 19, 2009]
+ Trivial cosmetic changes.
+
+Version 1.4.0beta87 [October 30, 2009]
+ Moved version 1.4.0 back into beta.
+
+Version 1.4.0beta88 [October 30, 2009]
+ Revised libpng*.txt section about differences between 1.2.x and 1.4.0
+ because most of the new features have now been ported back to 1.2.41
+
+Version 1.4.0beta89 [November 1, 2009]
+ More bugfixes and improvements to CMakeLists.txt (Philip Lowman)
+ Removed a harmless extra png_set_invert_alpha() from pngwrite.c
+ Apply png_user_chunk_cache_max within png_decompress_chunk().
+ Merged libpng-1.2.41.txt with libpng-1.4.0.txt where appropriate.
+
+Version 1.4.0beta90 [November 2, 2009]
+ Removed all remaining WIN32_WCE #ifdefs except those involving the
+ time.h "tm" structure
+
+Version 1.4.0beta91 [November 3, 2009]
+ Updated scripts/pngw32.def and projects/wince/png32ce.def
+ Copied projects/wince/png32ce.def to the scripts directory.
+ Added scripts/makefile.wce
+ Patched ltmain.sh for wince support.
+ Added PNG_CONVERT_tIME_SUPPORTED macro.
+
+Version 1.4.0beta92 [November 4, 2009]
+ Make inclusion of time.h in pngconf.h depend on PNG_CONVERT_tIME_SUPPORTED
+ Make #define PNG_CONVERT_tIME_SUPPORTED depend on PNG_WRITE_tIME_SUPPORTED
+ Revised libpng*.txt to describe differences from 1.2.40 to 1.4.0 (instead
+ of differences from 1.2.41 to 1.4.0)
+
+Version 1.4.0beta93 [November 7, 2009]
+ Added PNG_DEPSTRUCT, PNG_DEPRECATED, PNG_USE_RESULT, PNG_NORETURN, and
+ PNG_ALLOCATED macros to detect deprecated direct access to the
+ png_struct or info_struct members and other deprecated usage in
+ applications (John Bowler).
+ Updated scripts/makefile* to add "-DPNG_CONFIGURE_LIBPNG" to CFLAGS,
+ to prevent warnings about direct access to png structs by libpng
+ functions while building libpng. They need to be tested, especially
+ those using compilers other than gcc.
+ Updated projects/visualc6 and visualc71 with "/d PNG_CONFIGURE_LIBPNG".
+ They should work but still need to be updated to remove
+ references to pnggccrd.c or pngvcrd.c and ASM building.
+ Added README.txt to the beos, cbuilder5, netware, and xcode projects warning
+ that they need to be updated, to remove references to pnggccrd.c and
+ pngvcrd.c and to depend on pngpriv.h
+ Removed three direct references to read_info_ptr members in pngtest.c
+ that were detected by the new PNG_DEPSTRUCT macro.
+ Moved the png_debug macro definitions and the png_read_destroy(),
+ png_write_destroy() and png_far_to_near() prototypes from png.h
+ to pngpriv.h (John Bowler)
+ Moved the synopsis lines for png_read_destroy(), png_write_destroy()
+ png_debug(), png_debug1(), and png_debug2() from libpng.3 to libpngpf.3.
+
+Version 1.4.0beta94 [November 9, 2009]
+ Removed the obsolete, unused pnggccrd.c and pngvcrd.c files.
+ Updated CMakeLists.txt to add "-DPNG_CONFIGURE_LIBPNG" to the definitions.
+ Removed dependency of pngtest.o on pngpriv.h in the makefiles.
+ Only #define PNG_DEPSTRUCT, etc. in pngconf.h if not already defined.
+
+Version 1.4.0beta95 [November 10, 2009]
+ Changed png_check_sig() to !png_sig_cmp() in contrib programs.
+ Added -DPNG_CONFIGURE_LIBPNG to contrib/pngminm/*/makefile
+ Changed png_check_sig() to !png_sig_cmp() in contrib programs.
+ Corrected the png_get_IHDR() call in contrib/gregbook/readpng2.c
+ Changed pngminim/*/gather.sh to stop trying to remove pnggccrd.c and pngvcrd.c
+ Added dependency on pngpriv.h in contrib/pngminim/*/makefile
+
+Version 1.4.0beta96 [November 12, 2009]
+ Renamed scripts/makefile.wce to scripts/makefile.cegcc
+ Revised Makefile.am to use libpng.sys while building libpng.so
+ so that only PNG_EXPORT functions are exported.
+ Removed the deprecated png_check_sig() function/macro.
+ Removed recently removed function names from scripts/*.def
+ Revised pngtest.png to put chunks in the same order written by pngtest
+ (evidently the same change made in libpng-1.0beta54 was lost).
+ Added PNG_PRIVATE macro definition in pngconf.h for possible future use.
+
+Version 1.4.0beta97 [November 13, 2009]
+ Restored pngtest.png to the libpng-1.4.0beta7 version.
+ Removed projects/beos and netware.txt; no one seems to be supporting them.
+ Revised Makefile.in
+
+Version 1.4.0beta98 [November 13, 2009]
+ Added the "xcode" project to zip distributions,
+ Fixed a typo in scripts/pngwin.def introduced in beta97.
+
+Version 1.4.0beta99 [November 14, 2009]
+ Moved libpng-config.in and libpng.pc-configure.in out of the scripts
+ directory, to libpng-config.in and libpng-pc.in, respectively, and
+ modified Makefile.am and configure.ac accordingly. Now "configure"
+ needs nothing from the "scripts" directory.
+ Avoid redefining PNG_CONST in pngconf.h
+
+Version 1.4.0beta100 [November 14, 2009]
+ Removed ASM builds from projects/visualc6 and projects/visualc71
+ Removed scripts/makefile.nommx and makefile.vcawin32
+ Revised CMakeLists.txt to account for new location of libpng-config.in
+ and libpng-pc.in
+ Updated INSTALL to reflect removal and relocation of files.
+
+Version 1.4.0beta101 [November 14, 2009]
+ Restored the binary files (*.jpg, *.png, some project files) that were
+ accidentally deleted from the zip and 7z distributions when the xcode
+ project was added.
+
+Version 1.4.0beta102 [November 18, 2009]
+ Added libpng-config.in and libpng-pc.in to the zip and 7z distributions.
+ Fixed a typo in projects/visualc6/pngtest.dsp, introduced in beta100.
+ Moved descriptions of makefiles and other scripts out of INSTALL into
+ scripts/README.txt
+ Updated the copyright year in scripts/pngwin.rc from 2006 to 2009.
+
+Version 1.4.0beta103 [November 21, 2009]
+ Removed obsolete comments about ASM from projects/visualc71/README_zlib.txt
+ Align row_buf on 16-byte boundary in memory.
+ Restored the PNG_WRITE_FLUSH_AFTER_IEND_SUPPORTED guard around the call
+ to png_flush() after png_write_IEND(). See 1.4.0beta32, 1.4.0beta50
+ changes above and 1.2.30, 1.2.30rc01 and rc03 in 1.2.41 CHANGES. Someone
+ needs this feature.
+ Make the 'png_jmpbuf' macro expand to a call that records the correct
+ longjmp function as well as returning a pointer to the setjmp
+ jmp_buf buffer, and marked direct access to jmpbuf 'deprecated'.
+ (John Bowler)
+
+Version 1.4.0beta104 [November 22, 2009]
+ Removed png_longjmp_ptr from scripts/*.def and libpng.3
+ Rebuilt configure scripts with autoconf-2.65
+
+Version 1.4.0beta105 [November 25, 2009]
+ Use fast integer PNG_DIVIDE_BY_255() or PNG_DIVIDE_BY_65535()
+ to accomplish alpha premultiplication when
+ PNG_READ_COMPOSITE_NODIV_SUPPORTED is defined.
+ Changed "/255" to "/255.0" in background calculations to make it clear
+ that the 255 is used as a double.
+
+Version 1.4.0beta106 [November 27, 2009]
+ Removed premultiplied alpha feature.
+
+Version 1.4.0beta107 [December 4, 2009]
+ Updated README
+ Added "#define PNG_NO_PEDANTIC_WARNINGS" in the libpng source files.
+ Removed "-DPNG_CONFIGURE_LIBPNG" from the makefiles and projects.
+ Revised scripts/makefile.netbsd, makefile.openbsd, and makefile.sco
+ to put png.h and pngconf.h in $prefix/include, like the other scripts,
+ instead of in $prefix/include/libpng. Also revised makefile.sco
+ to put them in $prefix/include/libpng15 instead of in
+ $prefix/include/libpng/libpng15.
+
+Version 1.4.0beta108 [December 11, 2009]
+ Removed leftover "-DPNG_CONFIGURE_LIBPNG" from contrib/pngminim/*/makefile
+ Relocated png_do_chop() to its original position in pngrtran.c; the
+ change in version 1.2.41beta08 caused transparency to be handled wrong
+ in some 16-bit datastreams (Yusaku Sugai).
+
+Version 1.4.0beta109 [December 13, 2009]
+ Added "bit_depth" parameter to the private png_build_gamma_table() function.
+ Pass bit_depth=8 to png_build_gamma_table() when bit_depth is 16 but the
+ PNG_16_TO_8 transform has been set, to avoid unnecessary build of 16-bit
+ tables.
+
+Version 1.4.0rc02 [December 20, 2009]
+ Declared png_cleanup_needed "volatile" in pngread.c and pngwrite.c
+
+Version 1.4.0rc03 [December 22, 2009]
+ Renamed libpng-pc.in back to libpng.pc.in and revised CMakeLists.txt
+ (revising the change in 1.4.0beta99)
+
+Version 1.4.0rc04 [December 25, 2009]
+ Swapped PNG_UNKNOWN_CHUNKS_SUPPORTED and PNG_HANDLE_AS_UNKNOWN_SUPPORTED
+ in pngset.c to be consistent with other changes in version 1.2.38.
+
+Version 1.4.0rc05 [December 25, 2009]
+ Changed "libpng-pc.in" to "libpng.pc.in" in configure.ac, configure, and
+ Makefile.in to be consistent with changes in libpng-1.4.0rc03
+
+Version 1.4.0rc06 [December 29, 2009]
+ Reverted the gamma_table changes from libpng-1.4.0beta109.
+ Fixed some indentation errors.
+
+Version 1.4.0rc07 [January 1, 2010]
+ Revised libpng*.txt and libpng.3 about 1.2.x->1.4.x differences.
+ Use png_calloc() instead of png_malloc(); png_memset() in pngrutil.c
+ Update copyright year to 2010.
+
+Version 1.4.0rc08 [January 2, 2010]
+ Avoid deprecated references to png_ptr-io_ptr and png_ptr->error_ptr
+ in pngtest.c
+
+Version 1.4.0 [January 3, 2010]
+ No changes.
+
+Version 1.4.1beta01 [January 8, 2010]
+ Updated CMakeLists.txt for consistent indentation and to avoid an
+ unclosed if-statement warning (Philip Lowman).
+ Revised Makefile.am and Makefile.in to remove references to Y2KINFO,
+ KNOWNBUG, and libpng.la (Robert Schwebel).
+ Revised the makefiles to install the same files and symbolic
+ links as configure, except for libpng.la and libpng14.la.
+ Make png_set|get_compression_buffer_size() available even when
+ PNG_WRITE_SUPPORTED is not enabled.
+ Revised Makefile.am and Makefile.in to simplify their maintenance.
+ Revised scripts/makefile.linux to install a link to libpng14.so.14.1
+
+Version 1.4.1beta02 [January 9, 2010]
+ Revised the rest of the makefiles to install a link to libpng14.so.14.1
+
+Version 1.4.1beta03 [January 10, 2010]
+ Removed png_set_premultiply_alpha() from scripts/*.def
+
+Version 1.4.1rc01 [January 16, 2010]
+ No changes.
+
+Version 1.4.1beta04 [January 23, 2010]
+ Revised png_decompress_chunk() to improve speed and memory usage when
+ decoding large chunks.
+ Added png_set|get_chunk_malloc_max() functions.
+
+Version 1.4.1beta05 [January 26, 2010]
+ Relocated "int k" declaration in pngtest.c to minimize its scope.
+
+Version 1.4.1beta06 [January 28, 2010]
+ Revised png_decompress_chunk() to use a two-pass method suggested by
+ John Bowler.
+
+Version 1.4.1beta07 [February 6, 2010]
+ Folded some long lines in the source files.
+ Added defineable PNG_USER_CHUNK_CACHE_MAX, PNG_USER_CHUNK_MALLOC_MAX,
+ and a PNG_USER_LIMITS_SUPPORTED flag.
+ Eliminated use of png_ptr->irowbytes and reused the slot in png_ptr as
+ png_ptr->png_user_chunk_malloc_max.
+ Revised png_push_save_buffer() to do fewer but larger png_malloc() calls.
+
+Version 1.4.1beta08 [February 6, 2010]
+ Minor cleanup and updating of dates and copyright year.
+
+Version 1.5.0beta01 [February 7, 2010]
+ Moved declaration of png_struct into private pngstruct.h and png_info
+ into pnginfo.h
+
+Version 1.4.1beta09 and 1.5.0beta02 [February 7, 2010]
+ Reverted to original png_push_save_buffer() code.
+
+Version 1.4.1beta10 and 1.5.0beta03 [February 8, 2010]
+ Return allocated "old_buffer" in png_push_save_buffer() before
+ calling png_error(), to avoid a potential memory leak.
+ Updated configure script to use SO number 15.
+
+Version 1.5.0beta04 [February 9, 2010]
+ Removed malformed "incomplete struct declaration" of png_info from png.h
+
+Version 1.5.0beta05 [February 12, 2010]
+ Removed PNG_DEPSTRUCT markup in pngstruct.h and pnginfo.h, and undid the
+ linewrapping that it entailed.
+ Revised comments in pngstruct.h and pnginfo.h and added pointers to
+ the libpng license.
+ Changed PNG_INTERNAL to PNG_EXPOSE_INTERNAL_STRUCTURES
+ Removed the cbuilder5 project, which has not been updated to 1.4.0.
+
+Version 1.4.1beta12 and 1.5.0beta06 [February 14, 2010]
+ Fixed type declaration of png_get_chunk_malloc_max() in pngget.c (Daisuke
+ Nishikawa)
+
+Version 1.5.0beta07 [omitted]
+
+Version 1.5.0beta08 [February 19, 2010]
+ Changed #ifdef PNG_NO_STDIO_SUPPORTED to #ifdef PNG_NO_CONSOLE_IO_SUPPORTED
+ wherever png_snprintf() is used to construct error and warning messages.
+ Noted in scripts/makefile.mingw that it expects to be run under MSYS.
+ Removed obsolete unused MMX-querying support from contrib/gregbook
+ Added exported png_longjmp() function.
+ Removed the AIX redefinition of jmpbuf in png.h
+ Added -D_ALLSOURCE in configure.ac, makefile.aix, and CMakeLists.txt
+ when building on AIX.
+
+Version 1.5.0beta09 [February 19, 2010]
+ Removed -D_ALLSOURCE from configure.ac, makefile.aix, and CMakeLists.txt.
+ Changed the name of png_ptr->jmpbuf to png_ptr->png_jmpbuf in pngstruct.h
+
+Version 1.5.0beta10 [February 25, 2010]
+ Removed unused gzio.c from contrib/pngminim gather and makefile scripts
+ Removed replacement error handlers from contrib/gregbook. Because of
+ the new png_longjmp() function they are no longer needed.
+
+Version 1.5.0beta11 [March 6, 2010]
+ Removed checking for already-included setjmp.h from pngconf.h
+ Fixed inconsistent indentations and made numerous cosmetic changes.
+ Revised the "SEE ALSO" style of libpng.3, libpngpf.3, and png.5
+
+Version 1.5.0beta12 [March 9, 2010]
+ Moved "#include png.h" inside pngpriv.h and removed "#include png.h" from
+ the source files, along with "#define PNG_EXPOSE_INTERNAL_STRUCTURES"
+ and "#define PNG_NO_PEDANTIC_WARNINGS" (John Bowler).
+ Created new pngdebug.h and moved debug definitions there.
+
+Version 1.5.0beta13 [March 10, 2010]
+ Protect pngstruct.h, pnginfo.h, and pngdebug.h from being included twice.
+ Revise the "#ifdef" blocks in png_inflate() so it will compile when neither
+ PNG_USER_CHUNK_MALLOC_MAX nor PNG_SET_CHUNK_MALLOC_LIMIT_SUPPORTED
+ is defined.
+ Removed unused png_measure_compressed_chunk() from pngpriv.h and libpngpf.3
+ Moved the 'config.h' support from pngconf.h to pngpriv.h
+ Removed PNGAPI from the png_longjmp_ptr typedef.
+ Eliminated dependence of pngtest.c on the private pngdebug.h file.
+ Make all png_debug macros into *unterminated* statements or
+ expressions (i.e. a trailing ';' must always be added) and correct
+ the format statements in various png_debug messages.
+
+Version 1.5.0beta14 [March 14, 2010]
+ Removed direct access to png_ptr->io_ptr from the Windows code in pngtest.c
+ Revised Makefile.am to account for recent additions and replacements.
+ Corrected CE and OS/2 DEF files (scripts/png*def) for symbols removed and
+ added ordinal numbers to the Windows DEF file and corrected the duplicated
+ ordinal numbers on CE symbols that are commented out.
+ Added back in export symbols that can be present in the Windows build but
+ are disabled by default.
+ PNG_EXPORT changed to include an 'ordinal' field for DEF file generation.
+ PNG_CALLBACK added to make callback definitions uniform. PNGAPI split
+ into PNGCAPI (base C form), PNGAPI (exports) and PNGCBAPI (callbacks),
+ and appropriate changes made to all files. Cygwin builds re-hinged to
+ allow procedure call standard changes and to remove the need for the DEF
+ file (fixes build on Cygwin).
+ Enabled 'attribute' warnings that are relevant to library APIs and callbacks.
+ Changed rules for generation of the various symbol files and added a new
+ rule for a DEF file (which is also added to the distribution).
+ Updated the symbol file generation to stop it adding spurious spaces
+ to EOL (coming from preprocessor macro expansion). Added a facility
+ to join tokens in the output and rewrite *.dfn to use this.
+ Eliminated scripts/*.def in favor of libpng.def; updated projects/visualc71
+ and removed scripts/makefile.cygwin.
+ Made PNG_BUILD_DLL safe: it can be set whenever a DLL is being built.
+ Removed the include of sys/types.h - apparently unnecessary now on the
+ platforms on which it happened (all but Mac OS and RISC OS).
+ Moved the Mac OS test into pngpriv.h (the only place it is used.)
+
+Version 1.5.0beta15 [March 17, 2010]
+ Added symbols.chk target to Makefile.am to validate the symbols in png.h
+ against the new DEF file scripts/symbols.def.
+ Changed the default DEF file back to pngwin.def.
+ Removed makefile.mingw.
+ Eliminated PNG_NO_EXTERN and PNG_ALL_EXTERN
+
+Version 1.5.0beta16 [April 1, 2010]
+ Make png_text_struct independent of PNG_iTXt_SUPPORTED, so that
+ fields are initialized in all configurations. The READ/WRITE
+ macros (PNG_(READ|WRITE)_iTXt_SUPPORTED) still function as
+ before to disable code to actually read or write iTXt chunks
+ and iTXt_SUPPORTED can be used to detect presence of either
+ read or write support (but it is probably better to check for
+ the one actually required - read or write.)
+ Combined multiple png_warning() calls for a single error.
+ Restored the macro definition of png_check_sig().
+
+Version 1.5.0beta17 [April 17, 2010]
+ Added some "(long)" typecasts to printf calls in png_handle_cHRM().
+ Documented the fact that png_set_dither() was disabled since libpng-1.4.0.
+ Reenabled png_set_dither() but renamed it to png_set_quantize() to reflect
+ more accurately what it actually does. At the same time, renamed
+ the PNG_DITHER_[RED,GREEN_BLUE]_BITS macros to
+ PNG_QUANTIZE_[RED,GREEN,BLUE]_BITS.
+ Added some "(long)" typecasts to printf calls in png_handle_cHRM().
+ Freeze build-time only configuration in the build.
+ In all prior versions of libpng most configuration options
+ controlled by compiler #defines had to be repeated by the
+ application code that used libpng. This patch changes this
+ so that compilation options that can only be changed at build
+ time are frozen in the build. Options that are compiler
+ dependent (and those that are system dependent) are evaluated
+ each time - pngconf.h holds these. Options that can be changed
+ per-file in the application are in png.h. Frozen options are
+ in the new installed header file pnglibconf.h (John Bowler)
+ Removed the xcode project because it has not been updated to work
+ with libpng-1.5.0.
+ Removed the ability to include optional pngusr.h
+
+Version 1.5.0beta18 [April 17, 2010]
+ Restored the ability to include optional pngusr.h
+ Moved replacements for png_error() and png_warning() from the
+ contrib/pngminim project to pngerror.c, for use when warnings or
+ errors are disabled via PNG_NO_WARN or PNG_NO_ERROR_TEXT, to avoid
+ storing unneeded error/warning text.
+ Updated contrib/pngminim project to work with the new pnglibconf.h
+ Added some PNG_NO_* defines to contrib/pngminim/*/pngusr.h to save space.
+
+Version 1.5.0beta19 [April 24, 2010]
+ Added PNG_{READ,WRITE}_INT_FUNCTIONS_SUPPORTED. This allows the functions
+ to read and write ints to be disabled independently of PNG_USE_READ_MACROS,
+ which allows libpng to be built with the functions even though the default
+ is to use the macros - this allows applications to choose at app build
+ time whether or not to use macros (previously impossible because the
+ functions weren't in the default build.)
+ Changed Windows calling convention back to __cdecl for API functions.
+ For Windows/x86 platforms only:
+ __stdcall is no longer needed for Visual Basic, so libpng-1.5.0 uses
+ __cdecl throughout (both API functions and callbacks) on Windows/x86
+ platforms.
+ Replaced visualc6 and visualc71 projects with new vstudio project
+ Relaxed the overly-restrictive permissions of some files.
+
+Version 1.5.0beta20 [April 24, 2010]
+ Relaxed more overly-restrictive permissions of some files.
+
+Version 1.5.0beta21 [April 27, 2010]
+ Removed some unwanted binary bytes and changed CRLF to NEWLINE in the new
+ vstudio project files, and some trivial editing of some files in the
+ scripts directory.
+ Set PNG_NO_READ_BGR, PNG_NO_IO_STATE, and PNG_NO_TIME_RFC1123 in
+ contrib/pngminim/decoder/pngusr.h to make a smaller decoder application.
+
+Version 1.5.0beta22 [April 28, 2010]
+ Fixed dependencies of GET_INT_32 - it does not require READ_INT_FUNCTIONS
+ because it has a macro equivalent.
+ Improved the options.awk script; added an "everything off" option.
+ Revised contrib/pngminim to use the "everything off" option in pngusr.dfa.
+
+Version 1.5.0beta23 [April 29, 2010]
+ Corrected PNG_REMOVED macro to take five arguments.
+ The macro was documented with two arguments (name,ordinal), however
+ the symbol checking .dfn files assumed five arguments. The five
+ argument form seems more useful so it is changed to that.
+ Corrected PNG_UNKNOWN_CHUNKS_SUPPORTED to PNG_HANDLE_AS_UNKNOWN_SUPPORTED
+ in gregbook/readpng2.c
+ Corrected protection of png_get_user_transform_ptr. The API declaration in
+ png.h is removed if both READ and WRITE USER_TRANSFORM are turned off
+ but was left defined in pngtrans.c
+ Added logunsupported=1 to cause pnglibconf.h to document disabled options.
+ This makes the installed pnglibconf.h more readable but causes no
+ other change. The intention is that users of libpng will find it
+ easier to understand if an API they need is missing.
+ Include png_reset_zstream() in png.c only when PNG_READ_SUPPORTED is defined.
+ Removed dummy_inflate.c from contrib/pngminim/encoder
+ Removed contrib/pngminim/*/gather.sh; gathering is now done in the makefile.
+
+Version 1.5.0beta24 [May 7, 2010]
+ Use bitwise "&" instead of arithmetic mod in pngrutil.c calculation of the
+ offset of the png_ptr->rowbuf pointer into png_ptr->big_row_buf.
+ Added more blank lines for readability.
+
+Version 1.5.0beta25 [June 18, 2010]
+ In pngpread.c: png_push_have_row() add check for new_row > height
+ Removed the now-redundant check for out-of-bounds new_row from example.c
+
+Version 1.5.0beta26 [June 18, 2010]
+ In pngpread.c: png_push_process_row() add check for too many rows.
+
+Version 1.5.0beta27 [June 18, 2010]
+ Removed the check added in beta25 as it is now redundant.
+
+Version 1.5.0beta28 [June 20, 2010]
+ Rewrote png_process_IDAT_data to consistently treat extra data as warnings
+ and handle end conditions more cleanly.
+ Removed the new (beta26) check in png_push_process_row().
+
+Version 1.5.0beta29 [June 21, 2010]
+ Revised scripts/options.awk to work on Sunos (but still doesn't work)
+ Added comment to options.awk and contrib/pngminim/*/makefile to try nawk.
+
+Version 1.5.0beta30 [June 22, 2010]
+ Stop memory leak when reading a malformed sCAL chunk.
+
+Version 1.5.0beta31 [June 26, 2010]
+ Revised pngpread.c patch of beta28 to avoid an endless loop.
+ Removed some trailing blanks.
+
+Version 1.5.0beta32 [June 26, 2010]
+ Removed leftover scripts/options.patch and scripts/options.rej
+
+Version 1.5.0beta33 [July 6, 3010]
+ Made FIXED and FLOATING options consistent in the APIs they enable and
+ disable. Corrected scripts/options.awk to handle both command line
+ options and options specified in the .dfa files.
+ Changed char *msg to PNG_CONST char *msg in pngrutil.c
+ Make png_set_sRGB_gAMA_and_cHRM set values using either the fixed or
+ floating point APIs, but not both.
+ Reversed patch to remove error handler when the jmp_buf is stored in the
+ main program structure, not the png_struct.
+ The error handler is needed because the default handler in libpng will
+ always use the jmp_buf in the library control structure; this is never
+ set. The gregbook code is a useful example because, even though it
+ uses setjmp/longjmp, it shows how error handling can be implemented
+ using control mechanisms not directly supported by libpng. The
+ technique will work correctly with mechanisms such as Microsoft
+ Structure Exceptions or C++ exceptions (compiler willing - note that gcc
+ does not by default support interworking of C and C++ error handling.)
+ Reverted changes to call png_longjmp in contrib/gregbook where it is not
+ appropriate. If mainprog->jmpbuf is used by setjmp, then png_longjmp
+ cannot be used.
+ Changed "extern PNG_EXPORT" to "PNG_EXPORT" in png.h (Jan Nijtmans)
+ Changed "extern" to "PNG_EXTERN" in pngpriv.h (except for the 'extern "C" {')
+
+Version 1.5.0beta34 [July 12, 2010]
+ Put #ifndef PNG_EXTERN, #endif around the define PNG_EXTERN in pngpriv.h
+
+Version 1.5.0beta35 [July 24, 2010]
+ Removed some newly-added TAB characters.
+ Added -DNO_PNG_SNPRINTF to CFLAGS in scripts/makefile.dj2
+ Moved the definition of png_snprintf() outside of the enclosing
+ #ifdef blocks in pngconf.h
+
+Version 1.5.0beta36 [July 29, 2010]
+ Patches by John Bowler:
+ Fixed point APIs are now supported throughout (no missing APIs).
+ Internal fixed point arithmetic support exists for all internal floating
+ point operations.
+ sCAL validates the floating point strings it is passed.
+ Safe, albeit rudimentary, Watcom support is provided by PNG_API_RULE==2
+ Two new APIs exist to get the number of passes without turning on the
+ PNG_INTERLACE transform and to get the number of rows in the current
+ pass.
+ A new test program, pngvalid.c, validates the gamma code.
+ Errors in the 16-bit gamma correction (overflows) have been corrected.
+ cHRM chunk testing is done consistently (previously the floating point
+ API bypassed it, because the test really didn't work on FP, now the test
+ is performed on the actual values to be stored in the PNG file so it
+ works in the FP case too.)
+ Most floating point APIs now simply call the fixed point APIs after
+ converting the values to the fixed point form used in the PNG file.
+ The standard headers no longer include zlib.h, which is currently only
+ required for pngstruct.h and can therefore be internal.
+ Revised png_get_int_32 to undo the PNG two's complement representation of
+ negative numbers.
+
+Version 1.5.0beta37 [July 30, 2010]
+ Added a typecast in png_get_int_32() in png.h and pngrutil.h to avoid
+ a compiler warning.
+ Replaced oFFs 0,0 with oFFs -10,20 in pngtest.png
+
+Version 1.5.0beta38 [July 31, 2010]
+ Implemented remaining "_fixed" functions.
+ Corrected a number of recently introduced warnings mostly resulting from
+ safe but uncast assignments to shorter integers. Also added a zlib
+ VStudio release library project because the latest zlib Official Windows
+ build does not include such a thing.
+ Revised png_get_int_16() to be similar to png_get_int_32().
+ Restored projects/visualc71.
+
+Version 1.5.0beta39 [August 2, 2010]
+ VisualC/GCC warning fixes, VisualC build fixes
+ The changes include support for function attributes in VC in addition to
+ those already present in GCC - necessary because without these some
+ warnings are unavoidable. Fixes include signed/unsigned fixes in
+ pngvalid and checks with gcc -Wall -Wextra -Wunused.
+ VC requires function attributes on function definitions as well as
+ declarations, PNG_FUNCTION has been added to enable this and the
+ relevant function definitions changed.
+
+Version 1.5.0beta40 [August 6, 2010]
+ Correct use of _WINDOWS_ in pngconf.h
+ Removed png_mem_ #defines; they are no longer used.
+ Added the sRGB chunk to pngtest.png
+
+Version 1.5.0beta41 [August 11, 2010]
+ Added the cHRM chunk to pngtest.png
+ Don't try to use version-script with cygwin/mingw.
+ Revised contrib/gregbook to work under cygwin/mingw.
+
+Version 1.5.0beta42 [August 18, 2010]
+ Add .dll.a to the list of extensions to be symlinked by Makefile.am (Yaakov)
+ Made all API functions that have const arguments and constant string
+ literal pointers declare them (John Bowler).
+
+Version 1.5.0beta43 [August 20, 2010]
+ Removed spurious tabs, shorten long lines (no source change)
+ Also added scripts/chkfmt to validate the format of all the files that can
+ reasonably be validated (it is suggested to run "make distclean" before
+ checking, because some machine generated files have long lines.)
+ Reformatted the CHANGES file to be more consistent throughout.
+ Made changes to address various issues identified by GCC, mostly
+ signed/unsigned and shortening problems on assignment but also a few
+ difficult to optimize (for GCC) loops.
+ Fixed non-GCC fixed point builds. In png.c a declaration was misplaced
+ in an earlier update. Fixed to declare the auto variables at the head.
+ Use cexcept.h in pngvalid.c.
+
+Version 1.5.0beta44 [August 24, 2010]
+ Updated CMakeLists.txt to use CMAKE_INSTALL_LIBDIR variable; useful for
+ installing libpng in /usr/lib64 (Funda Wang).
+ Revised CMakeLists.txt to put the man pages in share/man/man* not man/man*
+ Revised CMakeLists.txt to make symlinks instead of copies when installing.
+ Changed PNG_LIB_NAME from pngNN to libpngNN in CMakeLists.txt (Philip Lowman)
+ Implemented memory checks within pngvalid
+ Reformatted/rearranged pngvalid.c to assist use of progressive reader.
+ Check interlaced images in pngvalid
+ Clarified pngusr.h comments in pnglibconf.dfa
+ Simplified the pngvalid error-handling code now that cexcept.h is in place.
+ Implemented progressive reader in pngvalid.c for standard tests
+ Implemented progressive read in pngvalid.c gamma tests
+ Turn on progressive reader in pngvalid.c by default and tidy code.
+
+Version 1.5.0beta45 [August 26, 2010]
+ Added an explicit make step to projects/vstudio for pnglibconf.h
+ Also corrected zlib.vcxproj into which Visual Studio had introduced
+ what it calls an "authoring error". The change to make pnglibconf.h
+ simply copies the file; in the future it may actually generate the
+ file from scripts/pnglibconf.dfa as the other build systems do.
+ Changed pngvalid to work when floating point APIs are disabled
+ Renamed the prebuilt scripts/pnglibconf.h to scripts/pnglibconf.h.prebuilt
+ Supply default values for PNG_USER_PRIVATEBUILD and PNG_USER_DLLFNAME_POSTFIX
+ in pngpriv.h in case the user neglected to define them in their pngusr.h
+
+Version 1.5.0beta46 [August 28, 2010]
+ Added new private header files to libpng_sources in CMakeLists.txt
+ Added PNG_READ_16BIT, PNG_WRITE_16BIT, and PNG_16BIT options.
+ Added reference to scripts/pnglibconf.h.prebuilt in the visualc71 project.
+
+Version 1.5.0beta47 [September 11, 2010]
+ Fixed a number of problems with 64-bit compilation reported by Visual
+ Studio 2010 (John Bowler).
+
+Version 1.5.0beta48 [October 4, 2010]
+ Updated CMakeLists.txt (Philip Lowman).
+ Revised autogen.sh to recognize and use $AUTOCONF, $AUTOMAKE, $AUTOHEADER,
+ $AUTOPOINT, $ACLOCAL and $LIBTOOLIZE
+ Fixed problem with symbols creation in Makefile.am which was assuming that
+ all versions of ccp write to standard output by default (Martin Banky). The
+ bug was introduced in libpng-1.2.9beta5.
+ Removed unused mkinstalldirs.
+
+Version 1.5.0beta49 [October 8, 2010]
+ Undid Makefile.am revision of 1.5.0beta48.
+
+Version 1.5.0beta50 [October 14, 2010]
+ Revised Makefile.in to account for mkinstalldirs being removed.
+ Added some "(unsigned long)" typecasts in printf statements in pngvalid.c.
+ Suppressed a compiler warning in png_handle_sPLT().
+ Check for out-of-range text compression mode in png_set_text().
+
+Version 1.5.0beta51 [October 15, 2010]
+ Changed embedded dates to "(PENDING RELEASE) in beta releases (and future
+ rc releases) to minimize the difference between releases.
+
+Version 1.5.0beta52 [October 16, 2010]
+ Restored some of the embedded dates (in png.h, png.c, documentation, etc.)
+
+Version 1.5.0beta53 [October 18, 2010]
+ Updated INSTALL to mention using "make maintainer-clean" and to remove
+ obsolete statement about a custom ltmain.sh
+ Disabled "color-tests" by default in Makefile.am so it will work with
+ automake versions earlier than 1.11.1
+ Use document name "libpng-manual.txt" instead of "libpng-<version>.txt"
+ to simplify version differences.
+ Removed obsolete remarks about setjmp handling from INSTALL.
+ Revised and renamed the typedef in png.h and png.c that was designed
+ to catch library and header mismatch.
+
+Version 1.5.0beta54 [November 10, 2010]
+ Require 48 bytes, not 64 bytes, for big_row_buf in overflow checks.
+ Used a consistent structure for the pngget.c functions.
+
+Version 1.5.0beta55 [November 21, 2010]
+ Revised png_get_uint_32, png_get_int_32, png_get_uint_16 (Cosmin)
+ Moved reading of file signature into png_read_sig (Cosmin)
+ Fixed atomicity of chunk header serialization (Cosmin)
+ Added test for io_state in pngtest.c (Cosmin)
+ Added "#!/bin/sh" at the top of contrib/pngminim/*/gather.sh scripts.
+ Changes to remove gcc warnings (John Bowler)
+ Certain optional gcc warning flags resulted in warnings in libpng code.
+ With these changes only -Wconversion and -Wcast-qual cannot be turned on.
+ Changes are trivial rearrangements of code. -Wconversion is not possible
+ for pngrutil.c (because of the widespread use of += et al on variables
+ smaller than (int) or (unsigned int)) and -Wcast-qual is not possible
+ with pngwio.c and pngwutil.c because the 'write' callback and zlib
+ compression both fail to declare their input buffers with 'const'.
+
+Version 1.5.0beta56 [December 7, 2010]
+ Added the private PNG_UNUSED() macro definition in pngpriv.h.
+ Added some commentary about PNG_EXPORT in png.h and pngconf.h
+ Revised PNG_EXPORT() macro and added PNG_EXPORTA() macro, with the
+ objective of simplifying and improving the cosmetic appearance of png.h.
+ Fixed some incorrect "=" macro names in pnglibconf.dfa
+ Included documentation of changes in 1.5.0 from 1.4.x in libpng-manual.txt
+
+Version 1.5.0beta57 [December 9, 2010]
+ Documented the pngvalid gamma error summary with additional comments and
+ print statements.
+ Improved missing symbol handling in checksym.awk; symbols missing in both
+ the old and new files can now be optionally ignored, treated as errors
+ or warnings.
+ Removed references to pngvcrd.c and pnggccrd.c from the vstudio project.
+ Updated "libpng14" to "libpng15" in the visualc71 project.
+ Enabled the strip16 tests in pngvalid.`
+ Don't display test results (except PASS/FAIL) when running "make test".
+ Instead put them in pngtest-log.txt
+ Added "--with-zprefix=<string>" to configure.ac
+ Updated the prebuilt configuration files to autoconf version 2.68
+
+Version 1.5.0beta58 [December 19, 2010]
+ Fixed interlace image handling and add test cases (John Bowler)
+ Fixed the clean rule in Makefile.am to remove pngtest-log.txt
+ Made minor changes to work around warnings in gcc 3.4
+
+Version 1.5.0rc01 [December 27, 2010]
+ No changes.
+
+Version 1.5.0rc02 [December 27, 2010]
+ Eliminated references to the scripts/*.def files in project/visualc71.
+
+Version 1.5.0rc03 [December 28, 2010]
+ Eliminated scripts/*.def and revised Makefile.am accordingly
+
+Version 1.5.0rc04 [December 29, 2010]
+ Fixed bug in background transformation handling in pngrtran.c (it was
+ looking for the flag in png_ptr->transformations instead of in
+ png_ptr->flags) (David Raymond).
+
+Version 1.5.0rc05 [December 31, 2010]
+ Fixed typo in a comment in CMakeLists.txt (libpng14 => libpng15) (Cosmin)
+
+Version 1.5.0rc06 [January 4, 2011]
+ Changed the new configure option "zprefix=string" to "zlib-prefix=string"
+
+Version 1.5.0rc07 [January 4, 2011]
+ Updated copyright year.
+
+Version 1.5.0 [January 6, 2011]
+ No changes.
+
+version 1.5.1beta01 [January 8, 2011]
+ Added description of png_set_crc_action() to the manual.
+ Added a note in the manual that the type of the iCCP profile was changed
+ from png_charpp to png_bytepp in png_get_iCCP(). This change happened
+ in version 1.5.0beta36 but is not noted in the CHANGES. Similarly,
+ it was changed from png_charpp to png_const_bytepp in png_set_iCCP().
+ Ensure that png_rgb_to_gray ignores palette mapped images, if libpng
+ internally happens to call it with one, and fixed a failure to handle
+ palette mapped images correctly. This fixes CVE-2690.
+
+Version 1.5.1beta02 [January 14, 2011]
+ Fixed a bug in handling of interlaced images (bero at arklinux.org).
+ Updated CMakeLists.txt (Clifford Yapp)
+
+Version 1.5.1beta03 [January 14, 2011]
+ Fixed typecasting of some png_debug() statements (Cosmin)
+
+Version 1.5.1beta04 [January 16, 2011]
+ Updated documentation of png_set|get_tRNS() (Thomas Klausner).
+ Mentioned in the documentation that applications must #include "zlib.h"
+ if they need access to anything in zlib.h, and that a number of
+ macros such as png_memset() are no longer accessible by applications.
+ Corrected pngvalid gamma test "sample" function to access all of the color
+ samples of each pixel, instead of sampling the red channel three times.
+ Prefixed variable names index, div, exp, gamma with "png_" to avoid "shadow"
+ warnings, and (mistakenly) changed png_exp() to exp().
+
+Version 1.5.1beta05 [January 16, 2011]
+ Changed variable names png_index, png_div, png_exp, and png_gamma to
+ char_index, divisor, exp_b10, and gamma_val, respectively, and
+ changed exp() back to png_exp().
+
+Version 1.5.1beta06 [January 20, 2011]
+ Prevent png_push_crc_skip() from hanging while reading an unknown chunk
+ or an over-large compressed zTXt chunk with the progressive reader.
+ Eliminated more GCC "shadow" warnings.
+ Revised png_fixed() in png.c to avoid compiler warning about reaching the
+ end without returning anything.
+
+Version 1.5.1beta07 [January 22, 2011]
+ In the manual, describe the png_get_IHDR() arguments in the correct order.
+ Added const_png_structp and const_png_infop types, and used them in
+ prototypes for most png_get_*() functions.
+
+Version 1.5.1beta08 [January 23, 2011]
+ Added png_get_io_chunk_type() and deprecated png_get_io_chunk_name()
+ Added synopses for the IO_STATE functions and other missing synopses
+ to the manual. Removed the synopses from libpngpf.3 because they
+ were out of date and no longer useful. Better information can be
+ obtained by reading the prototypes and comments in pngpriv.h
+ Attempted to fix cpp on Solaris with S. Studio 12 cc, fix build
+ Added a make macro DFNCPP that is a CPP that will accept the tokens in
+ a .dfn file and adds configure stuff to test for such a CPP. ./configure
+ should fail if one is not available.
+ Corrected const_png_ in png.h to png_const_ to avoid polluting the namespace.
+ Added png_get_current_row_number and png_get_current_pass_number for the
+ benefit of the user transform callback.
+ Added png_process_data_pause and png_process_data_skip for the benefit of
+ progressive readers that need to stop data processing or want to optimize
+ skipping of unread data (e.g., if the reader marks a chunk to be skipped.)
+
+Version 1.5.1beta09 [January 24, 2011]
+ Enhanced pngvalid, corrected an error in gray_to_rgb, corrected doc error.
+ pngvalid contains tests of transforms, which tests are currently disabled
+ because they are incompletely tested. gray_to_rgb was failing to expand
+ the bit depth for smaller bit depth images; this seems to be a long
+ standing error and resulted, apparently, in invalid output
+ (CVE-2011-0408, CERT VU#643140). The documentation did not accurately
+ describe what libpng really does when converting RGB to gray.
+
+Version 1.5.1beta10 [January 27, 2010]
+ Fixed incorrect examples of callback prototypes in the manual, that were
+ introduced in libpng-1.0.0.
+ In addition the order of the png_get_uint macros with respect to the
+ relevant function definitions has been reversed. This helps the
+ preprocessing of the symbol files be more robust. Furthermore, the
+ symbol file preprocessing now uses -DPNG_NO_USE_READ_MACROS even when
+ the library may actually be built with PNG_USE_READ_MACROS; this stops
+ the read macros interfering with the symbol file format.
+ Made the manual, synopses, and function prototypes use the function
+ argument names file_gamma, int_file_gamma, and srgb_intent consistently.
+
+Version 1.5.1beta11 [January 28, 2011]
+ Changed PNG_UNUSED from "param=param;" to "{if(param){}}".
+ Corrected local variable type in new API png_process_data_skip()
+ The type was self-evidently incorrect but only causes problems on 64-bit
+ architectures.
+ Added transform tests to pngvalid and simplified the arguments.
+
+Version 1.5.1rc01 [January 29, 2011]
+ No changes.
+
+Version 1.5.1rc02 [January 31, 2011]
+ Added a request in the manual that applications do not use "png_" or
+ "PNG_" to begin any of their own symbols.
+ Changed PNG_UNUSED to "(void)param;" and updated the commentary in pngpriv.h
+
+Version 1.5.1 [February 3, 2011]
+ No changes.
+
+Version 1.5.2beta01 [February 13, 2011]
+ More -Wshadow fixes for older gcc compilers. Older gcc versions apparently
+ check formal parameters names in function declarations (as well as
+ definitions) to see if they match a name in the global namespace.
+ Revised PNG_EXPORTA macro to not use an empty parameter, to accommodate the
+ old VisualC++ preprocessor.
+ Turned on interlace handling in png_read_png().
+ Fixed gcc pendantic warnings.
+ Handle longjmp in Cygwin.
+ Fixed png_get_current_row_number() in the interlaced case.
+ Cleaned up ALPHA flags and transformations.
+ Implemented expansion to 16 bits.
+
+Version 1.5.2beta02 [February 19, 2011]
+ Fixed mistake in the descriptions of user read_transform and write_transform
+ function prototypes in the manual. The row_info struct is png_row_infop.
+ Reverted png_get_current_row_number() to previous (1.5.2beta01) behavior.
+ Corrected png_get_current_row_number documentation
+ Fixed the read/write row callback documentation.
+ This documents the current behavior, where the callback is called after
+ every row with information pertaining to the next row.
+
+Version 1.5.2beta03 [March 3, 2011]
+ Fixed scripts/makefile.vcwin32
+ Updated contrib/pngsuite/README to add the word "modify".
+ Define PNG_ALLOCATED to blank when _MSC_VER<1300.
+
+Version 1.5.2rc01 [March 19, 2011]
+ Define remaining attributes to blank when MSC_VER<1300.
+ ifdef out mask arrays in pngread.c when interlacing is not supported.
+
+Version 1.5.2rc02 [March 22, 2011]
+ Added a hint to try CPP=/bin/cpp if "cpp -E" fails in scripts/pnglibconf.mak
+ and in contrib/pngminim/*/makefile, eg., on SunOS 5.10, and removed "strip"
+ from the makefiles.
+ Fixed a bug (present since libpng-1.0.7) that makes png_handle_sPLT() fail
+ to compile when PNG_NO_POINTER_INDEXING is defined (Chubanov Kirill)
+
+Version 1.5.2rc03 [March 24, 2011]
+ Don't include standard header files in png.h while building the symbol table,
+ to avoid cpp failure on SunOS (introduced PNG_BUILDING_SYMBOL_TABLE macro).
+
+Version 1.5.2 [March 31, 2011]
+ No changes.
+
+Version 1.5.3beta01 [April 1, 2011]
+ Re-initialize the zlib compressor before compressing non-IDAT chunks.
+ Added API functions (png_set_text_compression_level() and four others) to
+ set parameters for zlib compression of non-IDAT chunks.
+
+Version 1.5.3beta02 [April 3, 2011]
+ Updated scripts/symbols.def with new API functions.
+ Only compile the new zlib re-initializing code when text or iCCP is
+ supported, using PNG_WRITE_COMPRESSED_TEXT_SUPPORTED macro.
+ Improved the optimization of the zlib CMF byte (see libpng-1.2.6beta03).
+ Optimize the zlib CMF byte in non-IDAT compressed chunks
+
+Version 1.5.3beta03 [April 16, 2011]
+ Fixed gcc -ansi -pedantic compile. A strict ANSI system does not have
+ snprintf, and the "__STRICT_ANSI__" detects that condition more reliably
+ than __STDC__ (John Bowler).
+ Removed the PNG_PTR_NORETURN attribute because it too dangerous. It tells
+ the compiler that a user supplied callback (the error handler) does not
+ return, yet there is no guarantee in practice that the application code
+ will correctly implement the error handler because the compiler only
+ issues a warning if there is a mistake (John Bowler).
+ Removed the no-longer-used PNG_DEPSTRUCT macro.
+ Updated the zlib version to 1.2.5 in the VStudio project.
+ Fixed 64-bit builds where png_uint_32 is smaller than png_size_t in
+ pngwutil.c (John Bowler).
+ Fixed bug with stripping the filler or alpha channel when writing, that
+ was introduced in libpng-1.5.2beta01 (bug report by Andrew Church).
+
+Version 1.5.3beta04 [April 27, 2011]
+ Updated pngtest.png with the new zlib CMF optimization.
+ Cleaned up conditional compilation code and of background/gamma handling
+ Internal changes only except a new option to avoid compiling the
+ png_build_grayscale_palette API (which is not used at all internally.)
+ The main change is to move the transform tests (READ_TRANSFORMS,
+ WRITE_TRANSFORMS) up one level to the caller of the APIs. This avoids
+ calls to spurious functions if all transforms are disabled and slightly
+ simplifies those functions. Pngvalid modified to handle this.
+ A minor change is to stop the strip_16 and expand_16 interfaces from
+ disabling each other; this allows the future alpha premultiplication
+ code to use 16-bit intermediate values while still producing 8-bit output.
+ png_do_background and png_do_gamma have been simplified to take a single
+ pointer to the png_struct rather than pointers to every item required
+ from the png_struct. This makes no practical difference to the internal
+ code.
+ A serious bug in the pngvalid internal routine 'standard_display_init' has
+ been fixed - this failed to initialize the red channel and accidentally
+ initialized the alpha channel twice.
+ Changed png_struct jmp_buf member name from png_jmpbuf to tmp_jmpbuf to
+ avoid a possible clash with the png_jmpbuf macro on some platforms.
+
+Version 1.5.3beta05 [May 6, 2011]
+ Added the "_POSIX_SOURCE" feature test macro to ensure libpng sees the
+ correct API. _POSIX_SOURCE is defined in pngpriv.h, pngtest.c and
+ pngvalid.c to ensure that POSIX conformant systems disable non-POSIX APIs.
+ Removed png_snprintf and added formatted warning messages. This change adds
+ internal APIs to allow png_warning messages to have parameters without
+ requiring the host OS to implement snprintf. As a side effect the
+ dependency of the tIME-supporting RFC1132 code on stdio is removed and
+ PNG_NO_WARNINGS does actually work now.
+ Pass "" instead of '\0' to png_default_error() in png_err(). This mistake
+ was introduced in libpng-1.2.20beta01. This fixes CVE-2011-2691.
+ Added PNG_WRITE_OPTIMIZE_CMF_SUPPORTED macro to make the zlib "CMF" byte
+ optimization configureable.
+ IDAT compression failed if preceded by a compressed text chunk (bug
+ introduced in libpng-1.5.3beta01-02). This was because the attempt to
+ reset the zlib stream in png_write_IDAT happened after the first IDAT
+ chunk had been deflated - much too late. In this change internal
+ functions were added to claim/release the z_stream and, hopefully, make
+ the code more robust. Also deflateEnd checking is added - previously
+ libpng would ignore an error at the end of the stream.
+
+Version 1.5.3beta06 [May 8, 2011]
+ Removed the -D_ALL_SOURCE from definitions for AIX in CMakeLists.txt
+ Implemented premultiplied alpha support: png_set_alpha_mode API
+
+Version 1.5.3beta07 [May 11, 2011]
+ Added expand_16 support to the high level interface.
+ Added named value and 'flag' gamma support to png_set_gamma. Made a minor
+ change from the previous (unreleased) ABI/API to hide the exact value used
+ for Macs - it's not a good idea to embed this in the ABI!
+ Moved macro definitions for PNG_HAVE_IHDR, PNG_HAVE_PLTE, and PNG_AFTER_IDAT
+ from pngpriv.h to png.h because they must be visible to applications
+ that call png_set_unknown_chunks().
+ Check for up->location !PNG_AFTER_IDAT when writing unknown chunks
+ before IDAT.
+
+Version 1.5.3beta08 [May 16, 2011]
+ Improved "pngvalid --speed" to exclude more of pngvalid from the time.
+ Documented png_set_alpha_mode(), other changes in libpng.3/libpng-manual.txt
+ The cHRM chunk now sets the defaults for png_set_rgb_to_gray() (when negative
+ parameters are supplied by the caller), while in the absence of cHRM
+ sRGB/Rec 709 values are still used. This introduced a divide-by-zero
+ bug in png_handle_cHRM().
+ The bKGD chunk no longer overwrites the background value set by
+ png_set_background(), allowing the latter to be used before the file
+ header is read. It never performed any useful function to override
+ the default anyway.
+ Added memory overwrite and palette image checks to pngvalid.c
+ Previously palette image code was poorly checked. Since the transformation
+ code has a special palette path in most cases this was a severe weakness.
+ Minor cleanup and some extra checking in pngrutil.c and pngrtran.c. When
+ expanding an indexed image, always expand to RGBA if transparency is
+ present.
+
+Version 1.5.3beta09 [May 17, 2011]
+ Reversed earlier 1.5.3 change of transformation order; move png_expand_16
+ back where it was. The change doesn't work because it requires 16-bit
+ gamma tables when the code only generates 8-bit ones. This fails
+ silently; the libpng code just doesn't do any gamma correction. Moving
+ the tests back leaves the old, inaccurate, 8-bit gamma calculations, but
+ these are clearly better than none!
+
+Version 1.5.3beta10 [May 20, 2011]
+
+ png_set_background() and png_expand_16() did not work together correctly.
+ This problem is present in 1.5.2; if png_set_background is called with
+ need_expand false and the matching 16 bit color libpng erroneously just
+ treats it as an 8-bit color because of where png_do_expand_16 is in the
+ transform list. This simple fix reduces the supplied colour to 8-bits,
+ so it gets smashed, but this is better than the current behavior.
+ Added tests for expand16, more fixes for palette image tests to pngvalid.
+ Corrects the code for palette image tests and disables attempts to
+ validate palette colors.
+
+Version 1.5.3rc01 [June 3, 2011]
+ No changes.
+
+Version 1.5.3rc02 [June 8, 2011]
+ Fixed uninitialized memory read in png_format_buffer() (Bug report by
+ Frank Busse, CVE-2011-2501, related to CVE-2004-0421).
+
+Version 1.5.3beta11 [June 11, 2011]
+ Fixed png_handle_sCAL which is broken in 1.5. This fixes CVE 2011-2692.
+ Added sCAL to pngtest.png
+ Revised documentation about png_set_user_limits() to say that it also affects
+ png writing.
+ Revised handling of png_set_user_limits() so that it can increase the
+ limit beyond the PNG_USER_WIDTH|HEIGHT_MAX; previously it could only
+ reduce it.
+ Make the 16-to-8 scaling accurate. Dividing by 256 with no rounding is
+ wrong (high by one) 25% of the time. Dividing by 257 with rounding is
+ wrong in 128 out of 65536 cases. Getting the right answer all the time
+ without division is easy.
+ Added "_SUPPORTED" to the PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION macro.
+ Added projects/owatcom, an IDE project for OpenWatcom to replace
+ scripts/makefile.watcom. This project works with OpenWatcom 1.9. The
+ IDE autogenerates appropriate makefiles (libpng.mk) for batch processing.
+ The project is configurable, unlike the Visual Studio project, so long
+ as the developer has an awk.
+ Changed png_set_gAMA to limit the gamma value range so that the inverse
+ of the stored value cannot overflow the fixed point representation,
+ and changed other things OpenWatcom warns about.
+ Revised pngvalid.c to test PNG_ALPHA_MODE_SUPPORTED correctly. This allows
+ pngvalid to build when ALPHA_MODE is not supported, which is required if
+ it is to build on libpng 1.4.
+ Removed string/memory macros that are no longer used and are not
+ necessarily fully supportable, particularly png_strncpy and png_snprintf.
+ Added log option to pngvalid.c and attempted to improve gamma messages.
+
+Version 1.5.3 [omitted]
+ People found the presence of a beta release following an rc release
+ to be confusing; therefore we bump the version to libpng-1.5.4beta01
+ and there will be no libpng-1.5.3 release.
+
+Version 1.5.4beta01 [June 14, 2011]
+ Made it possible to undefine PNG_READ_16_TO_8_ACCURATE_SCALE_SUPPORTED
+ to get the same (inaccurate) output as libpng-1.5.2 and earlier.
+ Moved definitions of PNG_HAVE_IHDR, PNG_AFTER_IDAT, and PNG_HAVE_PLTE
+ outside of an unknown-chunk block in png.h because they are also
+ needed for other uses.
+
+Version 1.5.4beta02 [June 14, 2011]
+ Fixed and clarified LEGACY 16-to-8 scaling code.
+ Added png_set_chop_16() API, to match inaccurate results from previous
+ libpng versions.
+ Removed the ACCURATE and LEGACY options (they are no longer useable)
+ Use the old scaling method for background if png_set_chop_16() was
+ called.
+ Made png_set_chop_16() API removeable by disabling PNG_CHOP_16_TO_8_SUPPORTED
+
+Version 1.5.4beta03 [June 15, 2011]
+ Fixed a problem in png_do_expand_palette() exposed by optimization in
+ 1.5.3beta06
+ Also removed a spurious and confusing "trans" member ("trans") from png_info.
+ The palette expand optimization prevented expansion to an intermediate RGBA
+ form if tRNS was present but alpha was marked to be stripped; this exposed
+ a check for tRNS in png_do_expand_palette() which is inconsistent with the
+ code elsewhere in libpng.
+ Correction to the expand_16 code; removed extra instance of
+ png_set_scale_16_to_8 from pngpriv.h
+
+Version 1.5.4beta04 [June 16, 2011]
+ Added a missing "#ifdef PNG_READ_BACKGROUND_SUPPORTED/#endif" in pngrtran.c
+ Added PNG_TRANSFORM_CHOP_16 to the high-level read transforms.
+ Made PNG_READ_16_TO_8_ACCURATE_SCALE configurable again. If this is
+ not enabled, png_set_strip_16() and png_do_scale_16_to_8() aren't built.
+ Revised contrib/visupng, gregbook, and pngminim to demonstrate chop_16_to_8
+
+Version 1.5.4beta05 [June 16, 2011]
+ Renamed png_set_strip_16() to png_set_scale_16() and renamed
+ png_set_chop_16() to png_set_strip(16) in an attempt to minimize the
+ behavior changes between libpng14 and libpng15.
+
+Version 1.5.4beta06 [June 18, 2011]
+ Fixed new bug that was causing both strip_16 and scale_16 to be applied.
+
+Version 1.5.4beta07 [June 19, 2011]
+ Fixed pngvalid, simplified macros, added checking for 0 in sCAL.
+ The ACCURATE scale macro is no longer defined in 1.5 - call the
+ png_scale_16_to_8 API. Made sure that PNG_READ_16_TO_8 is still defined
+ if the png_strip_16_to_8 API is present. png_check_fp_number now
+ maintains some state so that positive, negative and zero values are
+ identified. sCAL uses these to be strictly spec conformant.
+
+Version 1.5.4beta08 [June 23, 2011]
+ Fixed pngvalid if ACCURATE_SCALE is defined.
+ Updated scripts/pnglibconf.h.prebuilt.
+
+Version 1.5.4rc01 [June 30, 2011]
+ Define PNG_ALLOCATED to "restrict" only if MSC_VER >= 1400.
+
+Version 1.5.4 [July 7, 2011]
+ No changes.
+
+Version 1.5.5beta01 [July 13, 2011]
+ Fixed some typos and made other minor changes in the manual.
+ Updated contrib/pngminus/makefile.std (Samuli Souminen)
+
+Version 1.5.5beta02 [July 14, 2011]
+ Revised Makefile.am and Makefile.in to look in the right directory for
+ pnglibconf.h.prebuilt
+
+Version 1.5.5beta03 [July 27, 2011]
+ Enabled compilation with g++ compiler. This compiler does not recognize
+ the file extension, so it always compiles with C++ rules. Made minor
+ changes to pngrutil.c to cast results where C++ expects it but C does not.
+ Minor editing of libpng.3 and libpng-manual.txt.
+
+Version 1.5.5beta04 [July 29, 2011]
+ Revised CMakeLists.txt (Clifford Yapp)
+ Updated commentary about the png_rgb_to_gray() default coefficients
+ in the manual and in pngrtran.c
+
+Version 1.5.5beta05 [August 17, 2011]
+ Prevent unexpected API exports from non-libpng DLLs on Windows. The "_DLL"
+ is removed from the test of whether a DLL is being built (this erroneously
+ caused the libpng APIs to be marked as DLL exports in static builds under
+ Microsoft Visual Studio). Almost all of the libpng building configuration
+ is moved from pngconf.h to pngpriv.h, but PNG_DLL_EXPORT remains in
+ pngconf.h, though, so that it is colocated with the import definition (it
+ is no longer used anywhere in the installed headers). The VStudio project
+ definitions have been cleaned up: "_USRDLL" has been removed from the
+ static library builds (this was incorrect), and PNG_USE_DLL has been added
+ to pngvalid to test the functionality (pngtest does not supply it,
+ deliberately). The spurious "_EXPORTS" has been removed from the
+ libpng build (all these errors were a result of copy/paste between project
+ configurations.)
+ Added new types and internal functions for CIE RGB end point handling to
+ pngpriv.h (functions yet to be implemented).
+
+Version 1.5.5beta06 [August 26, 2011]
+ Ensure the CMAKE_LIBRARY_OUTPUT_DIRECTORY is set in CMakeLists.txt
+ (Clifford Yap)
+ Fixes to rgb_to_gray and cHRM XYZ APIs (John Bowler):
+ The rgb_to_gray code had errors when combined with gamma correction.
+ Some pixels were treated as true grey when they weren't and such pixels
+ and true grey ones were not gamma corrected (the original value of the
+ red component was used instead). APIs to get and set cHRM using color
+ space end points have been added and the rgb_to_gray code that defaults
+ based on cHRM, and the divide-by-zero bug in png_handle_cHRM (CERT
+ VU#477046, CVE-2011-3328, introduced in 1.5.4) have been corrected.
+ A considerable number of tests has been added to pngvalid for the
+ rgb_to_gray transform.
+ Arithmetic errors in rgb_to_gray whereby the calculated gray value was
+ truncated to the bit depth rather than rounded have been fixed except in
+ the 8-bit non-gamma-corrected case (where consistency seems more important
+ than correctness.) The code still has considerable inaccuracies in the
+ 8-bit case because 8-bit linear arithmetic is used.
+
+Version 1.5.5beta07 [September 7, 2011]
+ Added "$(ARCH)" option to makefile.darwin
+ Added SunOS support to configure.ac and Makefile.am
+ Changed png_chunk_benign_error() to png_warning() in png.c, in
+ png_XYZ_from_xy_checked().
+
+Version 1.5.5beta08 [September 10, 2011]
+ Fixed 64-bit compilation errors (gcc). The errors fixed relate
+ to conditions where types that are 32 bits in the GCC 32-bit
+ world (uLong and png_size_t) become 64 bits in the 64-bit
+ world. This produces potential truncation errors which the
+ compiler correctly flags.
+ Relocated new HAVE_SOLARIS_LD definition in configure.ac
+ Constant changes for 64-bit compatibility (removal of L suffixes). The
+ 16-bit cases still use "L" as we don't have a 16-bit test system.
+
+Version 1.5.5rc01 [September 15, 2011]
+ Removed "L" suffixes in pngpriv.h
+
+Version 1.5.5 [September 22, 2011]
+ No changes.
+
+Version 1.5.6beta01 [September 22, 2011]
+ Fixed some 64-bit type conversion warnings in pngrtran.c
+ Moved row_info from png_struct to a local variable.
+ The various interlace mask arrays have been made into arrays of
+ bytes and made PNG_CONST and static (previously some arrays were
+ marked PNG_CONST and some weren't).
+ Additional checks have been added to the transform code to validate the
+ pixel depths after the transforms on both read and write.
+ Removed some redundant code from pngwrite.c, in png_destroy_write_struct().
+ Changed chunk reading/writing code to use png_uint_32 instead of png_byte[4].
+ This removes the need to allocate temporary strings for chunk names on
+ the stack in the read/write code. Unknown chunk handling still uses the
+ string form because this is exposed in the API.
+
+Version 1.5.6beta02 [September 26, 2011]
+ Added a note in the manual the png_read_update_info() must be called only
+ once with a particular info_ptr.
+ Fixed a typo in the definition of the new PNG_STRING_FROM_CHUNK(s,c) macro.
+
+Version 1.5.6beta03 [September 28, 2011]
+ Revised test-pngtest.sh to report FAIL when pngtest fails.
+ Added "--strict" option to pngtest, to report FAIL when the failure is
+ only because the resulting valid files are different.
+ Revised CMakeLists.txt to work with mingw and removed some material from
+ CMakeLists.txt that is no longer useful in libpng-1.5.
+
+Version 1.5.6beta04 [October 5, 2011]
+ Fixed typo in Makefile.in and Makefile.am ("-M Wl" should be "-M -Wl")."
+
+Version 1.5.6beta05 [October 12, 2011]
+ Speed up png_combine_row() for interlaced images. This reduces the generality
+ of the code, allowing it to be optimized for Adam7 interlace. The masks
+ passed to png_combine_row() are now generated internally, avoiding
+ some code duplication and localizing the interlace handling somewhat.
+ Align png_struct::row_buf - previously it was always unaligned, caused by
+ a bug in the code that attempted to align it; the code needs to subtract
+ one from the pointer to take account of the filter byte prepended to
+ each row.
+ Optimized png_combine_row() when rows are aligned. This gains a small
+ percentage for 16-bit and 32-bit pixels in the typical case where the
+ output row buffers are appropriately aligned. The optimization was not
+ previously possible because the png_struct buffer was always misaligned.
+ Fixed bug in png_write_chunk_header() debug print, introduced in 1.5.6beta01.
+
+Version 1.5.6beta06 [October 17, 2011]
+ Removed two redundant tests for unitialized row.
+ Fixed a relatively harmless memory overwrite in compressed text writing
+ with a 1 byte zlib buffer.
+ Add ability to call png_read_update_info multiple times to pngvalid.c.
+ Fixes for multiple calls to png_read_update_info. These fixes attend to
+ most of the errors revealed in pngvalid, however doing the gamma work
+ twice results in inaccuracies that can't be easily fixed. There is now
+ a warning in the code if this is going to happen.
+ Turned on multiple png_read_update_info in pngvalid transform tests.
+ Prevent libpng from overwriting unused bits at the end of the image when
+ it is not byte aligned, while reading. Prior to libpng-1.5.6 libpng would
+ overwrite the partial byte at the end of each row if the row width was not
+ an exact multiple of 8 bits and the image is not interlaced.
+
+Version 1.5.6beta07 [October 21, 2011]
+ Made png_ptr->prev_row an aligned pointer into png_ptr->big_prev_row
+ (Mans Rullgard).
+
+Version 1.5.6rc01 [October 26, 2011]
+ Changed misleading "Missing PLTE before cHRM" warning to "Out of place cHRM"
+
+Version 1.5.6rc02 [October 27, 2011]
+ Added LSR() macro to defend against buggy compilers that evaluate non-taken
+ code branches and complain about out-of-range shifts.
+
+Version 1.5.6rc03 [October 28, 2011]
+ Renamed the LSR() macro to PNG_LSR() and added PNG_LSL() macro.
+ Fixed compiler warnings with Intel and MSYS compilers. The logical shift
+ fix for Microsoft Visual C is required by other compilers, so this
+ enables that fix for all compilers when using compile-time constants.
+ Under MSYS 'byte' is a name declared in a system header file, so we
+ changed the name of a local variable to avoid the warnings that result.
+ Added #define PNG_ALIGN_TYPE PNG_ALIGN_NONE to contrib/pngminim/*/pngusr.h
+
+Version 1.5.6 [November 3, 2011]
+ No changes.
+
+Version 1.5.7beta01 [November 4, 2011]
+ Added support for ARM processor, when decoding all PNG up-filtered rows
+ and any other-filtered rows with 3 or 4 bytes per pixel (Mans Rullgard).
+ Fixed bug in pngvalid on early allocation failure; fixed type cast in
+ pngmem.c; pngvalid would attempt to call png_error() if the allocation
+ of a png_struct or png_info failed. This would probably have led to a
+ crash. The pngmem.c implementation of png_malloc() included a cast
+ to png_size_t which would fail on large allocations on 16-bit systems.
+ Fix for the preprocessor of the Intel C compiler. The preprocessor
+ splits adjacent @ signs with a space; this changes the concatentation
+ token from @-@-@ to PNG_JOIN; that should work with all compiler
+ preprocessors.
+ Paeth filter speed improvements from work by Siarhei Siamashka. This
+ changes the 'Paeth' reconstruction function to improve the GCC code
+ generation on x86. The changes are only part of the suggested ones;
+ just the changes that definitely improve speed and remain simple.
+ The changes also slightly increase the clarity of the code.
+
+Version 1.5.7beta02 [November 11, 2011]
+ Check compression_type parameter in png_get_iCCP and remove spurious
+ casts. The compression_type parameter is always assigned to, so must
+ be non-NULL. The cast of the profile length potentially truncated the
+ value unnecessarily on a 16-bit int system, so the cast of the (byte)
+ compression type to (int) is specified by ANSI-C anyway.
+ Fixed FP division by zero in pngvalid.c; the 'test_pixel' code left
+ the sBIT fields in the test pixel as 0, which resulted in a floating
+ point division by zero which was irrelevant but causes systems where
+ FP exceptions cause a crash. Added code to pngvalid to turn on FP
+ exceptions if the appropriate glibc support is there to ensure this is
+ tested in the future.
+ Updated scripts/pnglibconf.mak and scripts/makefile.std to handle the
+ new PNG_JOIN macro.
+ Added versioning to pnglibconf.h comments.
+ Simplified read/write API initial version; basic read/write tested on
+ a variety of images, limited documentation (in the header file.)
+ Installed more accurate linear to sRGB conversion tables. The slightly
+ modified tables reduce the number of 16-bit values that
+ convert to an off-by-one 8-bit value. The "makesRGB.c" code that was used
+ to generate the tables is now in a contrib/sRGBtables sub-directory.
+
+Version 1.5.7beta03 [November 17, 2011]
+ Removed PNG_CONST from the sRGB table declarations in pngpriv.h and png.c
+ Added run-time detection of NEON support.
+ Added contrib/libtests; includes simplified API test and timing test and
+ a color conversion utility for rapid checking of failed 'pngstest' results.
+ Multiple transform bug fixes plus a work-round for double gamma correction.
+ libpng does not support more than one transform that requires linear data
+ at once - if this is tried typically the results is double gamma
+ correction. Since the simplified APIs can need rgb to gray combined with
+ a compose operation it is necessary to do one of these outside the main
+ libpng transform code. This check-in also contains fixes to various bugs
+ in the simplified APIs themselves and to some bugs in compose and rgb to
+ gray (on palette) itself.
+ Fixes for C++ compilation using g++ When libpng source is compiled
+ using g++. The compiler imposes C++ rules on the C source; thus it
+ is desireable to make the source work with either C or C++ rules
+ without throwing away useful error information. This change adds
+ png_voidcast to allow C semantic (void*) cases or the corresponding
+ C++ static_cast operation, as appropriate.
+ Added --noexecstack to assembler file compilation. GCC does not set
+ this on assembler compilation, even though it does on C compilation.
+ This creates security issues if assembler code is enabled; the
+ work-around is to set it by default in the flags for $(CCAS)
+ Work around compilers that don't support declaration of const data. Some
+ compilers fault 'extern const' data declarations (because the data is
+ not initialized); this turns on const-ness only for compilers where
+ this is known to work.
+
+Version 1.5.7beta04 [November 17, 2011]
+ Since the gcc driver does not recognize the --noexecstack flag, we must
+ use the -Wa prefix to have it passed through to the assembler.
+ Also removed a duplicate setting of this flag.
+ Added files that were omitted from the libpng-1.5.7beta03 zip distribution.
+
+Version 1.5.7beta05 [November 25, 2011]
+ Removed "zTXt" from warning in generic chunk decompression function.
+ Validate time settings passed to pngset() and png_convert_to_rfc1123()
+ (Frank Busse).
+ Added MINGW support to CMakeLists.txt
+ Reject invalid compression flag or method when reading the iTXt chunk.
+ Backed out 'simplified' API changes. The API seems too complex and there
+ is a lack of consensus or enthusiasm for the proposals. The API also
+ reveals significant bugs inside libpng (double gamma correction and the
+ known bug of being unable to retrieve a corrected palette). It seems
+ better to wait until the bugs, at least, are corrected.
+ Moved pngvalid.c into contrib/libtests
+ Rebuilt Makefile.in, configure, etc., with autoconf-2.68
+
+Version 1.5.7rc01 [December 1, 2011]
+ Replaced an "#if" with "#ifdef" in pngrtran.c
+ Revised #if PNG_DO_BC block in png.c (use #ifdef and add #else)
+
+Version 1.5.7rc02 [December 5, 2011]
+ Revised project files and contrib/pngvalid/pngvalid.c to account for
+ the relocation of pngvalid into contrib/libtests.
+ Revised pngconf.h to use " __declspec(restrict)" only when MSC_VER >= 1400,
+ as in libpng-1.5.4.
+ Put CRLF line endings in the owatcom project files.
+
+Version 1.5.7rc03 [December 7, 2011]
+ Updated CMakeLists.txt to account for the relocation of pngvalid.c
+
+Version 1.5.7 [December 15, 2011]
+ Minor fixes to pngvalid.c for gcc 4.6.2 compatibility to remove warnings
+ reported by earlier versions.
+ Fixed minor memset/sizeof errors in pngvalid.c.
+
+Version 1.6.0beta01 [December 15, 2011]
+ Removed machine-generated configure files from the GIT repository (they will
+ continue to appear in the tarball distributions and in the libpng15 and
+ earlier GIT branches).
+ Restored the new 'simplified' API, which was started in libpng-1.5.7beta02
+ but later deleted from libpng-1.5.7beta05.
+ Added example programs for the new 'simplified' API.
+ Added ANSI-C (C90) headers and require them, and take advantage of the
+ change. Also fixed some of the projects/* and contrib/* files that needed
+ updates for libpng16 and the move of pngvalid.c.
+ With this change the required ANSI-C header files are assumed to exist: the
+ implementation must provide float.h, limits.h, stdarg.h and stddef.h and
+ libpng relies on limits.h and stddef.h existing and behaving as defined
+ (the other two required headers aren't used). Non-ANSI systems that don't
+ have stddef.h or limits.h will have to provide an appropriate fake
+ containing the relevant types and #defines.
+ The use of FAR/far has been eliminated and the definition of png_alloc_size_t
+ is now controlled by a flag so that 'small size_t' systems can select it
+ if necessary. Libpng 1.6 may not currently work on such systems -- it
+ seems likely that it will ask 'malloc' for more than 65535 bytes with any
+ image that has a sufficiently large row size (rather than simply failing
+ to read such images).
+ New tools directory containing tools used to generate libpng code.
+ Fixed race conditions in parallel make builds. With higher degrees of
+ parallelism during 'make' the use of the same temporary file names such
+ as 'dfn*' can result in a race where a temporary file from one arm of the
+ build is deleted or overwritten in another arm. This changes the
+ temporary files for suffix rules to always use $* and ensures that the
+ non-suffix rules use unique file names.
+
+Version 1.6.0beta02 [December 21, 2011]
+ Correct configure builds where build and source directories are separate.
+ The include path of 'config.h' was erroneously made relative in pngvalid.c
+ in libpng 1.5.7.
+
+Version 1.6.0beta03 [December 22, 2011]
+ Start-up code size improvements, error handler flexibility. These changes
+ alter how the tricky allocation of the initial png_struct and png_info
+ structures are handled. png_info is now handled in pretty much the same
+ way as everything else, except that the allocations handle NULL return
+ silently. png_struct is changed in a similar way on allocation and on
+ deallocation a 'safety' error handler is put in place (which should never
+ be required). The error handler itself is changed to permit mismatches
+ in the application and libpng error buffer size; however, this means a
+ silent change to the API to return the jmp_buf if the size doesn't match
+ the size from the libpng compilation; libpng now allocates the memory and
+ this may fail. Overall these changes result in slight code size
+ reductions; however, this is a reduction in code that is always executed
+ so is particularly valuable. Overall on a 64-bit system the libpng DLL
+ decreases in code size by 1733 bytes. pngerror.o increases in size by
+ about 465 bytes because of the new functionality.
+ Added png_convert_to_rfc1123_buffer() and deprecated png_convert_to_rfc1123()
+ to avoid including a spurious buffer in the png_struct.
+
+Version 1.6.0beta04 [December 30, 2011]
+ Regenerated configure scripts with automake-1.11.2
+ Eliminated png_info_destroy(). It is now used only in png.c and only calls
+ one other internal function and memset().
+ Enabled png_get_sCAL_fixed() if floating point APIs are enabled. Previously
+ it was disabled whenever internal fixed point arithmetic was selected,
+ which meant it didn't exist even on systems where FP was available but not
+ preferred.
+ Added pngvalid.c compile time checks for const APIs.
+ Implemented 'restrict' for png_info and png_struct. Because of the way
+ libpng works both png_info and png_struct are always accessed via a
+ single pointer. This means adding C99 'restrict' to the pointer gives
+ the compiler some opportunity to optimize the code. This change allows
+ that.
+ Moved AC_MSG_CHECKING([if libraries can be versioned]) later to the proper
+ location in configure.ac (Gilles Espinasse).
+ Changed png_memcpy to C assignment where appropriate. Changed all those
+ uses of png_memcpy that were doing a simple assignment to assignments
+ (all those cases where the thing being copied is a non-array C L-value).
+ Added some error checking to png_set_*() routines.
+ Removed the reference to the non-exported function png_memcpy() from
+ example.c.
+ Fixed the Visual C 64-bit build - it requires jmp_buf to be aligned, but
+ it had become misaligned.
+ Revised contrib/pngminus/pnm2png.c to avoid warnings when png_uint_32
+ and unsigned long are of different sizes.
+
+Version 1.6.0beta05 [January 15, 2012]
+ Updated manual with description of the simplified API (copied from png.h)
+ Fix bug in pngerror.c: some long warnings were being improperly truncated
+ (CVE-2011-3464, bug introduced in libpng-1.5.3beta05).
+
+Version 1.6.0beta06 [January 24, 2012]
+ Added palette support to the simplified APIs. This commit
+ changes some of the macro definitions in png.h, app code
+ may need corresponding changes.
+ Increased the formatted warning buffer to 192 bytes.
+ Added color-map support to simplified API. This is an initial version for
+ review; the documentation has not yet been updated.
+ Fixed Min/GW uninstall to remove libpng.dll.a
+
+Version 1.6.0beta07 [January 28, 2012]
+ Eliminated Intel icc/icl compiler warnings. The Intel (GCC derived)
+ compiler issues slightly different warnings from those issued by the
+ current vesions of GCC. This eliminates those warnings by
+ adding/removing casts and small code rewrites.
+ Updated configure.ac from autoupdate: added --enable-werror option.
+ Also some layout regularization and removal of introduced tab characters
+ (replaced with 3-character indentation). Obsolete macros identified by
+ autoupdate have been removed; the replacements are all in 2.59 so
+ the pre-req hasn't been changed. --enable-werror checks for support
+ for -Werror (or the given argument) in the compiler. This mimics the
+ gcc configure option by allowing -Werror to be turned on safely; without
+ the option the tests written in configure itself fail compilation because
+ they cause compiler warnings.
+ Rewrote autogen.sh to run autoreconf instead of running tools one-by-one.
+ Conditionalize the install rules for MINGW and CYGWIN in CMakeLists.txt and
+ set CMAKE_LIBRARY_OUTPUT_DIRECTORY to "lib" on all platforms (C. Yapp).
+ Freeze libtool files in the 'scripts' directory. This version of autogen.sh
+ attempts to dissuade people from running it when it is not, or should not,
+ be necessary. In fact, autogen.sh does not work when run in a libpng
+ directory extracted from a tar distribution anymore. You must run it in
+ a GIT clone instead.
+ Added two images to contrib/pngsuite (1-bit and 2-bit transparent grayscale),
+ and renamed three whose names were inconsistent with those in
+ pngsuite/README.txt.
+
+Version 1.6.0beta08 [February 1, 2012]
+ Fixed Image::colormap misalignment in pngstest.c
+ Check libtool/libtoolize version number (2.4.2) in configure.ac
+ Divide test-pngstest.sh into separate pngstest runs for basic and
+ transparent images.
+ Moved automake options to AM_INIT_AUTOMAKE in configure.ac
+ Added color-tests, silent-rules (Not yet implemented in Makefile.am) and
+ version checking to configure.ac
+ Improved pngstest speed by not doing redundant tests and add const to
+ the background parameter of png_image_finish_read. The --background
+ option is now done automagically only when required, so that commandline
+ option no longer exists.
+ Cleaned up pngpriv.h to consistently declare all functions and data.
+ Also eliminated PNG_CONST_DATA, which is apparently not needed but we
+ can't be sure until it is gone.
+ Added symbol prefixing that allows all the libpng external symbols
+ to be prefixed (suggested by Reuben Hawkins).
+ Updated "ftbb*.png" list in the owatcom and vstudio projects.
+ Fixed 'prefix' builds on clean systems. The generation of pngprefix.h
+ should not require itself.
+ Updated INSTALL to explain that autogen.sh must be run in a GIT clone,
+ not in a libpng directory extracted from a tar distribution.
+
+Version 1.6.0beta09 [February 1, 2012]
+ Reverted the prebuilt configure files to libpng-1.6.0beta05 condition.
+
+Version 1.6.0beta10 [February 3, 2012]
+ Added Z_SOLO for zlib-1.2.6+ and correct pngstest tests
+ Updated list of test images in CMakeLists.txt
+ Updated the prebuilt configure files to current condition.
+ Revised INSTALL information about autogen.sh; it works in tar distributions.
+
+Version 1.6.0beta11 [February 16, 2012]
+ Fix character count in pngstest command in projects/owatcom/pngstest.tgt
+ Revised test-pngstest.sh to report PASS/FAIL for each image.
+ Updated documentation about the simplified API.
+ Corrected estimate of error in libpng png_set_rgb_to_gray API. The API is
+ extremely inaccurate for sRGB conversions because it uses an 8-bit
+ intermediate linear value and it does not use the sRGB transform, so it
+ suffers from the known instability in gamma transforms for values close
+ to 0 (see Poynton). The net result is that the calculation has a maximum
+ error of 14.99/255; 0.5/255^(1/2.2). pngstest now uses 15 for the
+ permitted 8-bit error. This may still not be enough because of arithmetic
+ error.
+ Removed some unused arrays (with #ifdef) from png_read_push_finish_row().
+ Fixed a memory overwrite bug in simplified read of RGB PNG with
+ non-linear gamma Also bugs in the error checking in pngread.c and changed
+ quite a lot of the checks in pngstest.c to be correct; either correctly
+ written or not over-optimistic. The pngstest changes are insufficient to
+ allow all possible RGB transforms to be passed; pngstest cmppixel needs
+ to be rewritten to make it clearer which errors it allows and then changed
+ to permit known inaccuracies.
+ Removed tests for no-longer-used *_EMPTY_PLTE_SUPPORTED from pngstruct.h
+ Fixed fixed/float API export conditionals. 1) If FIXED_POINT or
+ FLOATING_POINT options were switched off, png.h ended up with lone ';'
+ characters. This is not valid ANSI-C outside a function. The ';'
+ characters have been moved inside the definition of PNG_FP_EXPORT and
+ PNG_FIXED_EXPORT. 2) If either option was switched off, the declaration
+ of the corresponding functions were completely omitted, even though some
+ of them are still used internally. The result is still valid, but
+ produces warnings from gcc with some warning options (including -Wall). The
+ fix is to cause png.h to declare the functions with PNG_INTERNAL_FUNCTION
+ when png.h is included from pngpriv.h.
+ Check for invalid palette index while reading paletted PNG. When one is
+ found, issue a warning and increase png_ptr->num_palette accordingly.
+ Apps are responsible for checking to see if that happened.
+
+Version 1.6.0beta12 [February 18, 2012]
+ Do not increase num_palette on invalid_index.
+ Relocated check for invalid palette index to pngrtran.c, after unpacking
+ the sub-8-bit pixels.
+ Fixed CVE-2011-3026 buffer overrun bug. This bug was introduced when
+ iCCP chunk support was added at libpng-1.0.6. Deal more correctly with the
+ test on iCCP chunk length. Also removed spurious casts that may hide
+ problems on 16-bit systems.
+
+Version 1.6.0beta13 [February 24, 2012]
+ Eliminated redundant png_push_read_tEXt|zTXt|iTXt|unknown code from
+ pngpread.c and use the sequential png_handle_tEXt, etc., in pngrutil.c;
+ now that png_ptr->buffer is inaccessible to applications, the special
+ handling is no longer useful.
+ Added PNG_SAFE_LIMITS feature to pnglibconf.dfa, pngpriv.h, and new
+ pngusr.dfa to reset the user limits to safe ones if PNG_SAFE_LIMITS is
+ defined. To enable, use "CPPFLAGS=-DPNG_SAFE_LIMITS_SUPPORTED=1" on the
+ configure command or put #define PNG_SAFE_LIMITS_SUPPORTED in
+ pnglibconf.h.prebuilt and pnglibconf.h.
+
+Version 1.6.0beta14 [February 27, 2012]
+ Added information about the new limits in the manual.
+ Updated Makefile.in
+
+Version 1.6.0beta15 [March 2, 2012]
+ Removed unused "current_text" members of png_struct and the png_free()
+ of png_ptr->current_text from pngread.c
+ Rewrote pngstest.c for substantial speed improvement.
+ Fixed transparent pixel and 16-bit rgb tests in pngstest and removed a
+ spurious check in pngwrite.c
+ Added PNG_IMAGE_FLAG_FAST for the benefit of applications that store
+ intermediate files, or intermediate in-memory data, while processing
+ image data with the simplified API. The option makes the files larger
+ but faster to write and read. pngstest now uses this by default; this
+ can be disabled with the --slow option.
+ Improved pngstest fine tuning of error numbers, new test file generator.
+ The generator generates images that test the full range of sample values,
+ allow the error numbers in pngstest to be tuned and checked. makepng
+ also allows generation of images with extra chunks, although this is
+ still work-in-progress.
+ Added check for invalid palette index while reading.
+ Fixed some bugs in ICC profile writing. The code should now accept
+ all potentially valid ICC profiles and reject obviously invalid ones.
+ It now uses png_error() to do so rather than casually writing a PNG
+ without the necessary color data.
+ Removed whitespace from the end of lines in all source files and scripts.
+
+Version 1.6.0beta16 [March 6, 2012]
+ Relocated palette-index checking function from pngrutil.c to pngtrans.c
+ Added palette-index checking while writing.
+ Changed png_inflate() and calling routines to avoid overflow problems.
+ This is an intermediate check-in that solves the immediate problems and
+ introduces one performance improvement (avoiding a copy via png_ptr->zbuf.)
+ Further changes will be made to make ICC profile handling more secure.
+ Fixed build warnings (MSVC, GCC, GCC v3). Cygwin GCC with default options
+ declares 'index' as a global, causing a warning if it is used as a local
+ variable. GCC 64-bit warns about assigning a (size_t) (unsigned 64-bit)
+ to an (int) (signed 32-bit). MSVC, however, warns about using the
+ unary '-' operator on an unsigned value (even though it is well defined
+ by ANSI-C to be ~x+1). The padding calculation was changed to use a
+ different method. Removed the tests on png_ptr->pass.
+ Added contrib/libtests/tarith.c to test internal arithmetic functions from
+ png.c. This is a libpng maintainer program used to validate changes to the
+ internal arithmetic functions.
+ Made read 'inflate' handling like write 'deflate' handling. The read
+ code now claims and releases png_ptr->zstream, like the write code.
+ The bug whereby the progressive reader failed to release the zstream
+ is now fixed, all initialization is delayed, and the code checks for
+ changed parameters on deflate rather than always calling
+ deflatedEnd/deflateInit.
+ Validate the zTXt strings in pngvalid.
+ Added code to validate the windowBits value passed to deflateInit2().
+ If the call to deflateInit2() is wrong a png_warning will be issued
+ (in fact this is harmless, but the PNG data produced may be sub-optimal).
+
+Version 1.6.0beta17 [March 10, 2012]
+ Fixed PNG_LIBPNG_BUILD_BASE_TYPE definition.
+ Reject all iCCP chunks after the first, even if the first one is invalid.
+ Deflate/inflate was reworked to move common zlib calls into single
+ functions [rw]util.c. A new shared keyword check routine was also added
+ and the 'zbuf' is no longer allocated on progressive read. It is now
+ possible to call png_inflate() incrementally. A warning is no longer
+ issued if the language tag or translated keyword in the iTXt chunk
+ has zero length.
+ If benign errors are disabled use maximum window on ancilliary inflate.
+ This works round a bug introduced in 1.5.4 where compressed ancillary
+ chunks could end up with a too-small windowBits value in the deflate
+ header.
+
+Version 1.6.0beta18 [March 16, 2012]
+ Issue a png_benign_error() instead of png_warning() about bad palette index.
+ In pngtest, treat benign errors as errors if "-strict" is present.
+ Fixed an off-by-one error in the palette index checking function.
+ Fixed a compiler warning under Cygwin (Windows-7, 32-bit system)
+ Revised example.c to put text strings in a temporary character array
+ instead of directly assigning string constants to png_textp members.
+ This avoids compiler warnings when -Wwrite-strings is enabled.
+ Added output flushing to aid debugging under Visual Studio. Unfortunately
+ this is necessary because the VS2010 output window otherwise simply loses
+ the error messages on error (they weren't flushed to the window before
+ the process exited, apparently!)
+ Added configuration support for benign errors and changed the read
+ default. Also changed some warnings in the iCCP and sRGB handling
+ from to benign errors. Configuration now makes read benign
+ errors warnings and write benign errors to errors by default (thus
+ changing the behavior on read). The simplified API always forces
+ read benign errors to warnings (regardless of the system default, unless
+ this is disabled in which case the simplified API can't be built.)
+
+Version 1.6.0beta19 [March 18, 2012]
+ Work around for duplicate row start calls; added warning messages.
+ This turns on PNG_FLAG_DETECT_UNINITIALIZED to detect app code that
+ fails to call one of the 'start' routines (not enabled in libpng-1.5
+ because it is technically an API change, since it did normally work
+ before.) It also makes duplicate calls to png_read_start_row (an
+ internal function called at the start of the image read) benign, as
+ they were before changes to use png_inflate_claim. Somehow webkit is
+ causing this to happen; this is probably a mis-feature in the zlib
+ changes so this commit is only a work-round.
+ Removed erroneous setting of DETECT_UNINITIALIZED and added more
+ checks. The code now does a png_error if an attempt is made to do the
+ row initialization twice; this is an application error and it has
+ serious consequences because the transform data in png_struct is
+ changed by each call.
+ Added application error reporting and added chunk names to read
+ benign errors; also added --strict to pngstest - not enabled
+ yet because a warning is produced.
+ Avoid the double gamma correction warning in the simplified API.
+ This allows the --strict option to pass in the pngstest checks
+
+Version 1.6.0beta20 [March 29, 2012]
+ Changed chunk handler warnings into benign errors, incrementally load iCCP
+ Added checksum-icc.c to contrib/tools
+ Prevent PNG_EXPAND+PNG_SHIFT doing the shift twice.
+ Recognize known sRGB ICC profiles while reading; prefer writing the
+ iCCP profile over writing the sRGB chunk, controlled by the
+ PNG_sRGB_PROFILE_CHECKS option.
+ Revised png_set_text_2() to avoid potential memory corruption (fixes
+ CVE-2011-3048, also known as CVE-2012-3425).
+
+Version 1.6.0beta21 [April 27, 2012]
+ Revised scripts/makefile.darwin: use system zlib; remove quotes around
+ architecture list; add missing ppc architecture; add architecture options
+ to shared library link; don't try to create a shared lib based on missing
+ RELEASE variable.
+ Enable png_set_check_for_invalid_index() for both read and write.
+ Removed #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED in pngpriv.h around
+ declaration of png_handle_unknown().
+ Added -lssp_nonshared in a comment in scripts/makefile.freebsd
+ and changed deprecated NOOBJ and NOPROFILE to NO_OBJ and NO_PROFILE.
+
+Version 1.6.0beta22 [May 23, 2012]
+ Removed need for -Wno-cast-align with clang. clang correctly warns on
+ alignment increasing pointer casts when -Wcast-align is passed. This
+ fixes the cases that clang warns about either by eliminating the
+ casts from png_bytep to png_uint_16p (pngread.c), or, for pngrutil.c
+ where the cast is previously verified or pngstest.c where it is OK, by
+ introducing new png_aligncast macros to do the cast in a way that clang
+ accepts.
+
+Version 1.6.0beta23 [June 6, 2012]
+ Revised CMakeLists.txt to not attempt to make a symlink under mingw.
+ Made fixes for new optimization warnings from gcc 4.7.0. The compiler
+ performs an optimization which is safe; however it then warns about it.
+ Changing the type of 'palette_number' in pngvalid.c removes the warning.
+ Do not depend upon a GCC feature macro being available for use in generating
+ the linker mapfile symbol prefix.
+ Improved performance of new do_check_palette_indexes() function (only
+ update the value when it actually increases, move test for whether
+ the check is wanted out of the function.
+
+Version 1.6.0beta24 [June 7, 2012]
+ Don't check palette indexes if num_palette is 0 (as it can be in MNG files).
+
+Version 1.6.0beta25 [June 16, 2012]
+ Revised png_set_keep_unknown_chunks() so num_chunks < 0 means ignore all
+ unknown chunks and all known chunks except for IHDR, PLTE, tRNS, IDAT,
+ and IEND. Previously it only meant ignore all unknown chunks, the
+ same as num_chunks == 0. Revised png_image_skip_unused_chunks() to
+ provide a list of chunks to be processed instead of a list of chunks to
+ ignore. Revised contrib/gregbook/readpng2.c accordingly.
+
+Version 1.6.0beta26 [July 10, 2012]
+ Removed scripts/makefile.cegcc from the *.zip and *.7z distributions; it
+ depends on configure, which is not included in those archives.
+ Moved scripts/chkfmt to contrib/tools.
+ Changed "a+w" to "u+w" in Makefile.in to fix CVE-2012-3386.
+
+Version 1.6.0beta27 [August 11, 2012]
+ Do not compile PNG_DEPRECATED, PNG_ALLOC and PNG_PRIVATE when __GNUC__ < 3.
+ Do not use __restrict when GNUC is <= 3.1
+ Removed references to png_zalloc() and png_zfree() from the manual.
+ Fixed configurations where floating point is completely disabled. Because
+ of the changes to support symbol prefixing PNG_INTERNAL_FUNCTION declares
+ floating point APIs during libpng builds even if they are completely
+ disabled. This requires the png floating point types (png_double*) to be
+ declared even though the functions are never actually defined. This
+ change provides a dummy definition so that the declarations work, yet any
+ implementation will fail to compile because of an incomplete type.
+ Re-eliminated the use of strcpy() in pngtest.c. An unncessary use of
+ strcpy() was accidentally re-introduced in libpng16; this change replaces
+ it with strncpy().
+ Eliminated use of png_sizeof(); use sizeof() instead.
+ Use a consistent style for (sizeof type) and (sizeof (array))
+ Cleanup of png_set_filler(). This function does very different things on
+ read and write. In libpng 1.6 the two cases can be distinguished and
+ considerable code cleanup, and extra error checking, is possible. This
+ makes calls on the write side that have no effect be ignored with a
+ png_app_error(), which can be disabled in the app using
+ png_set_benign_errors(), and removes the spurious use of usr_channels
+ on the read side.
+ Insist on autotools 1.12.1 for git builds because there are security issues
+ with 1.12 and insisting on anything less would allow 1.12 to be used.
+ Removed info_ptr->signature[8] from WRITE-only builds.
+ Add some conditions for compiling png_fixed(). This is a small function
+ but it requires "-lm" on some platforms.
+ Cause pngtest --strict to fail on any warning from libpng (not just errors)
+ and cause it not to fail at the comparison step if libpng lacks support
+ for writing chunks that it reads from the input (currently only implemented
+ for compressed text chunks).
+ Make all three "make check" test programs work without READ or WRITE support.
+ Now "make check" will succeed even if libpng is compiled with -DPNG_NO_READ
+ or -DPNG_NO_WRITE. The tests performed are reduced, but the basic reading
+ and writing of a PNG file is always tested by one or more of the tests.
+ Consistently use strlen(), memset(), memcpy(), and memcmp() instead of the
+ png_strlen(), png_memset(), png_memcpy(), and png_memcmp() macros.
+ Removed the png_sizeof(), png_strlen(), png_memset(), png_memcpy(), and
+ png_memcmp() macros.
+ Work around gcc 3.x and Microsoft Visual Studio 2010 complaints. Both object
+ to the split initialization of num_chunks.
+
+Version 1.6.0beta28 [August 29, 2012]
+ Unknown handling fixes and clean up. This adds more correct option
+ control of the unknown handling, corrects the pre-existing bug where
+ the per-chunk 'keep' setting is ignored and makes it possible to skip
+ IDAT chunks in the sequential reader (broken in earlier 1.6 versions).
+ There is a new test program, test-unknown.c, which is a work in progress
+ (not currently part of the test suite). Comments in the header files now
+ explain how the unknown handling works.
+ Allow fine grain control of unknown chunk APIs. This change allows
+ png_set_keep_unknown_chunks() to be turned off if not required and causes
+ both read and write to behave appropriately (on read this is only possible
+ if the user callback is used to handle unknown chunks). The change
+ also removes the support for storing unknown chunks in the info_struct
+ if the only unknown handling enabled is via the callback, allowing libpng
+ to be configured with callback reading and none of the unnecessary code.
+ Corrected fix for unknown handling in pngtest. This reinstates the
+ libpng handling of unknown chunks other than vpAg and sTER (including
+ unsafe-to-copy chunks which were dropped before) and eliminates the
+ repositioning of vpAg and sTER in pngtest.png by changing pngtest.png
+ (so the chunks are where libpng would put them).
+ Added "tunknown" test and corrected a logic error in png_handle_unknown()
+ when SAVE support is absent. Moved the shell test scripts for
+ contrib/libtests from the libpng top directory to contrib/libtests.
+ png_handle_unknown() must always read or skip the chunk, if
+ SAVE_UNKNOWN_CHUNKS is turned off *and* the application does not set
+ a user callback an unknown chunk will not be read, leading to a read
+ error, which was revealed by the "tunknown" test.
+ Cleaned up and corrected ICC profile handling.
+ contrib/libtests/makepng: corrected 'rgb' and 'gray' cases. profile_error
+ messages could be truncated; made a correct buffer size calculation and
+ adjusted pngerror.c appropriately. png_icc_check_* checking improved;
+ changed the functions to receive the correct color type of the PNG on read
+ or write and check that it matches the color space of the profile (despite
+ what the comments said before, there is danger in assuming the app will
+ cope correctly with an RGB profile on a grayscale image and, since it
+ violates the PNG spec, allowing it is certain to produce inconsistent
+ app behavior and might even cause app crashes.) Check that profiles
+ contain the tags needed to process the PNG (tags all required by the ICC
+ spec). Removed unused PNG_STATIC from pngpriv.h.
+
+Version 1.6.0beta29 [September 4, 2012]
+ Fixed the simplified API example programs to add the *colormap parameter
+ to several of he API and improved the error message if the version field
+ is not set.
+ Added contrib/examples/* to the *.zip and *.7z distributions.
+ Updated simplified API synopses and description of the png_image structure
+ in the manual.
+ Made makepng and pngtest produce identical PNGs, add "--relaxed" option
+ to pngtest. The "--relaxed" option turns off the benign errors that are
+ enabled by default in pre-RC builds. makepng can now write ICC profiles
+ where the length has not been extended to a multiple of 4, and pngtest
+ now intercepts all libpng errors, allowing the previously-introduced
+ "--strict test" on no warnings to actually work.
+ Improved ICC profile handling including cHRM chunk generation and fixed
+ Cygwin+MSVC build errors. The ICC profile handling now includes more
+ checking. Several errors that caused rejection of the profile are now
+ handled with a warning in such a way that the invalid profiles will be
+ read by default in release (but not pre-RC) builds but will not be
+ written by default. The easy part of handling the cHRM chunk is written,
+ where the ICC profile contains the required data. The more difficult
+ part plus guessing a gAMA value requires code to pass selected RGB values
+ through the profile.
+
+Version 1.6.0beta30 [October 24, 2012]
+ Changed ICC profile matrix/vector types to not depend on array type rules.
+ By the ANSI-C standard the new types should be identical to the previous
+ versions, and all known versions of gcc tested with the previous versions
+ except for GCC-4.2.1 work with this version. The change makes the ANSI-C
+ rule that const applied to an array of elements applies instead to the
+ elements in the array moot by explicitly applying const to the base
+ elements of the png_icc_matrix and png_icc_vector types. The accidental
+ (harmless) 'const' previously applied to the parameters of two of the
+ functions have also been removed.
+ Added a work around for GCC 4.2 optimization bug.
+ Marked the broken (bad white point) original HP sRGB profiles correctly and
+ correct comments.
+ Added -DZ_SOLO to contrib/pngminim/*/makefile to work with zlib-1.2.7
+ Use /MDd for vstudio debug builds. Also added pngunkown to the vstudio
+ builds, fixed build errors and corrected a minor exit code error in
+ pngvalid if the 'touch' file name is invalid.
+ Add updated WARNING file to projects/vstudio from libpng 1.5/vstudio
+ Fixed build when using #define PNG_NO_READ_GAMMA in png_do_compose() in
+ pngrtran.c (Domani Hannes).
+
+Version 1.6.0beta31 [November 1, 2012]
+ Undid the erroneous change to vstudio/pngvalid build in libpng-1.6.0beta30.
+ Made pngvalid so that it will build outside the libpng source tree.
+ Made builds -DPNG_NO_READ_GAMMA compile (the unit tests still fail).
+ Made PNG_NO_READ_GAMMA switch off interfaces that depend on READ_GAMMA.
+ Prior to 1.6.0 switching off READ_GAMMA did unpredictable things to the
+ interfaces that use it (specifically, png_do_background in 1.4 would
+ simply display composite for grayscale images but do composition
+ with the incorrect arithmetic for color ones). In 1.6 the semantic
+ of -DPNG_NO_READ_GAMMA is changed to simply disable any interface that
+ depends on it; this obliges people who set it to consider whether they
+ really want it off if they happen to use any of the interfaces in
+ question (typically most users who disable it won't).
+ Fixed GUIDs in projects/vstudio. Some were duplicated or missing,
+ resulting in VS2010 having to update the files.
+ Removed non-working ICC profile support code that was mostly added to
+ libpng-1.6.0beta29 and beta30. There was too much code for too little
+ gain; implementing full ICC color correction may be desireable but is left
+ up to applications.
+
+Version 1.6.0beta32 [November 25, 2012]
+ Fixed an intermittent SEGV in pngstest due to an uninitialized array element.
+ Added the ability for contrib/libtests/makepng.c to make a PNG with just one
+ color. This is useful for debugging pngstest color inaccuracy reports.
+ Fixed error checking in the simplified write API (Olaf van der Spek)
+ Made png_user_version_check() ok to use with libpng version 1.10.x and later.
+
+Version 1.6.0beta33 [December 15, 2012]
+ Fixed typo in png.c (PNG_SET_CHUNK_MALLOC_MAX should be PNG_CHUNK_MALLOC_MAX)
+ that causes the MALLOC_MAX limit not to work (John Bowler)
+ Change png_warning() to png_app_error() in pngwrite.c and comment the
+ fall-through condition.
+ Change png_warning() to png_app_warning() in png_write_tRNS().
+ Rearranged the ARM-NEON optimizations: Isolated the machine specific code
+ to the hardware subdirectory and added comments to pngrutil.c so that
+ implementors of other optimizations know what to do.
+ Fixed cases of unquoted DESTDIR in Makefile.am
+ Rebuilt Makefile.in, etc., with autoconf-2.69 and automake-1.12.5.
+
+Version 1.6.0beta34 [December 19, 2012]
+ Cleaned up whitespace in the synopsis portion of the manpage "libpng.3"
+ Disassembled the version number in scripts/options.awk (necessary for
+ building on SunOs).
+
+Version 1.6.0beta35 [December 23, 2012]
+ Made default Zlib compression settings be configurable. This adds #defines to
+ pnglibconf.h to control the defaults.
+ Fixed Windows build issues, enabled ARM compilation. Various warnings issued
+ by earlier versions of GCC fixed for Cygwin and Min/GW (which both use old
+ GCCs.) ARM support is enabled by default in zlib.props (unsupported by
+ Microsoft) and ARM compilation is made possible by deleting the check for
+ x86. The test programs cannot be run because they are not signed.
+
+Version 1.6.0beta36 [January 2, 2013]
+ Discontinued distributing libpng-1.x.x.tar.bz2.
+ Discontinued distributing libpng-1.7.0-1.6.0-diff.txt and similar.
+ Rebuilt configure with autoconf-2.69 (inadvertently not done in beta33)
+ Fixed 'make distcheck' on SUN OS - libpng.so was not being removed
+
+Version 1.6.0beta37 [January 10, 2013]
+ Fixed conceivable but difficult to repro overflow. Also added two test
+ programs to generate and test a PNG which should have the problem.
+
+Version 1.6.0beta39 [January 19, 2013]
+ Again corrected attempt at overflow detection in png_set_unknown_chunks()
+ (CVE-2013-7353). Added overflow detection in png_set_sPLT() and
+ png_set_text_2() (CVE-2013-7354).
+
+Version 1.6.0beta40 [January 20, 2013]
+ Use consistent handling of overflows in text, sPLT and unknown png_set_* APIs
+
+Version 1.6.0rc01 [January 26, 2013]
+ No changes.
+
+Version 1.6.0rc02 [February 4, 2013]
+ Added png_get_palette_max() function.
+
+Version 1.6.0rc03 [February 5, 2013]
+ Fixed the png_get_palette_max API.
+
+Version 1.6.0rc04 [February 7, 2013]
+ Turn serial tests back on (recently turned off by autotools upgrade).
+
+Version 1.6.0rc05 [February 8, 2013]
+ Update manual about png_get_palette_max().
+
+Version 1.6.0rc06 [February 9, 2013]
+ Fixed missing dependency in --prefix builds The intermediate
+ internal 'prefix.h' file can only be generated correctly after
+ pnglibconf.h, however the dependency was not in Makefile.am. The
+ symptoms are unpredictable depending on the order make chooses to
+ build pngprefix.h and pnglibconf.h, often the error goes unnoticed
+ because there is a system pnglibconf.h to use instead.
+
+Version 1.6.0rc07 [February 10, 2013]
+ Enclosed the new png_get_palette_max in #ifdef PNG_GET_PALETTE_MAX_SUPPORTED
+ block, and revised pnglibconf.h and pnglibconf.h.prebuilt accordingly.
+
+Version 1.6.0rc08 [February 10, 2013]
+ Fix typo in png.h #ifdef
+
+Version 1.6.0 [February 14, 2013]
+ No changes.
+
+Version 1.6.1beta01 [February 16, 2013]
+ Made symbol prefixing work with the ARM neon optimizations. Also allow
+ pngpriv.h to be included for preprocessor definitions only, so it can
+ be used in non-C/C++ files. Back ported from libpng 1.7.
+ Made sRGB check numbers consistent.
+ Ported libpng 1.5 options.awk/dfn file handling to 1.6, fixed one bug.
+ Removed cc -E workround, corrected png_get_palette_max API Tested on
+ SUN OS cc 5.9, which demonstrates the tokenization problem previously
+ avoided by using /lib/cpp. Since all .dfn output is now protected in
+ double quotes unless it is to be macro substituted the fix should
+ work everywhere.
+ Enabled parallel tests - back ported from libpng-1.7.
+ scripts/pnglibconf.dfa formatting improvements back ported from libpng17.
+ Fixed a race condition in the creation of the build 'scripts' directory
+ while building with a parallel make.
+ Use approved/supported Android method to check for NEON, use Linux/POSIX
+ 1003.1 API to check /proc/self/auxv avoiding buffer allocation and other
+ library calls (ported from libpng15).
+
+Version 1.6.1beta02 [February 19, 2013]
+ Use parentheses more consistently in "#if defined(MACRO)" tests.
+ Folded long lines.
+ Reenabled code to allow zero length PLTE chunks for MNG.
+
+Version 1.6.1beta03 [February 22, 2013]
+ Fixed ALIGNED_MEMORY support.
+ Allow run-time ARM NEON checking to be disabled. A new configure option:
+ --enable-arm-neon=always will stop the run-time checks. New checks
+ within arm/arm_init.c will cause the code not to be compiled unless
+ __ARM_NEON__ is set. This should make it fail safe (if someone asks
+ for it on then the build will fail if it can't be done.)
+ Updated the INSTALL document.
+
+Version 1.6.1beta04 [February 27, 2013]
+ Revised INSTALL to recommend using CPPFLAGS instead of INCLUDES.
+ Revised scripts/makefile.freebsd to respect ZLIBLIB and ZLIBINC.
+ Revised scripts/dfn.awk to work with the buggy MSYS awk that has trouble
+ with CRLF line endings.
+
+Version 1.6.1beta05 [March 1, 2013]
+ Avoid a possible memory leak in contrib/gregbook/readpng.c
+
+Version 1.6.1beta06 [March 4, 2013]
+ Better documentation of unknown handling API interactions.
+ Corrected Android builds and corrected libpng.vers with symbol
+ prefixing. This adds an API to set optimization options externally,
+ providing an alternative and general solution for the non-portable
+ run-time tests used by the ARM Neon code. It also makes those tests
+ compile and link on Android.
+ The order of settings vs options in pnglibconf.h is reversed to allow
+ settings to depend on options and options can now set (or override) the
+ defaults for settings.
+
+Version 1.6.1beta07 [March 7, 2013]
+ Corrected simplified API default gamma for color-mapped output, added
+ a flag to change default. In 1.6.0 when the simplified API was used
+ to produce color-mapped output from an input image with no gamma
+ information the gamma assumed for the input could be different from
+ that assumed for non-color-mapped output. In particular 16-bit depth
+ input files were assumed to be sRGB encoded, whereas in the 'direct'
+ case they were assumed to have linear data. This was an error. The
+ fix makes the simplified API treat all input files the same way and
+ adds a new flag to the png_image::flags member to allow the
+ application/user to specify that 16-bit files contain sRGB data
+ rather than the default linear.
+ Fixed bugs in the pngpixel and makepng test programs.
+
+Version 1.6.1beta08 [March 7, 2013]
+ Fixed CMakelists.txt to allow building a single variant of the library
+ (Claudio Bley):
+ Introduced a PNG_LIB_TARGETS variable that lists all activated library
+ targets. It is an error if this variable ends up empty, ie. you have
+ to build at least one library variant.
+ Made the *_COPY targets only depend on library targets actually being build.
+ Use PNG_LIB_TARGETS to unify a code path.
+ Changed the CREATE_SYMLINK macro to expect the full path to a file as the
+ first argument. When symlinking the filename component of that path is
+ determined and used as the link target.
+ Use copy_if_different in the CREATE_SYMLINK macro.
+
+Version 1.6.1beta09 [March 13, 2013]
+ Eliminated two warnings from the Intel C compiler. The warnings are
+ technically valid, although a reasonable treatment of division would
+ show it to be incorrect.
+
+Version 1.6.1rc01 [March 21, 2013]
+ No changes.
+
+Version 1.6.1 [March 28, 2013]
+ No changes.
+
+Version 1.6.2beta01 [April 14, 2013]
+ Updated documentation of 1.5.x to 1.6.x changes in iCCP chunk handling.
+ Fixed incorrect warning of excess deflate data. End condition - the
+ warning would be produced if the end of the deflate stream wasn't read
+ in the last row. The warning is harmless.
+ Corrected the test on user transform changes on read. It was in the
+ png_set of the transform function, but that doesn't matter unless the
+ transform function changes the rowbuf size, and that is only valid if
+ transform_info is called.
+ Corrected a misplaced closing bracket in contrib/libtests/pngvalid.c
+ (Flavio Medeiros).
+ Corrected length written to uncompressed iTXt chunks (Samuli Suominen).
+ Bug was introduced in libpng-1.6.0.
+
+Version 1.6.2rc01 [April 18, 2013]
+ Added contrib/tools/fixitxt.c, to repair the erroneous iTXt chunk length
+ written by libpng-1.6.0 and 1.6.1.
+ Disallow storing sRGB information when the sRGB is not supported.
+
+Version 1.6.2rc02 [April 18, 2013]
+ Merge pngtest.c with libpng-1.7.0
+
+Version 1.6.2rc03 [April 22, 2013]
+ Trivial spelling cleanup.
+
+Version 1.6.2rc04 and 1.6.2rc05 [omitted]
+
+Version 1.6.2rc06 [April 24, 2013]
+ Reverted to version 1.6.2rc03. Recent changes to arm/neon support
+ have been ported to libpng-1.7.0beta09 and will reappear in version
+ 1.6.3beta01.
+
+Version 1.6.2 [April 25, 2013]
+ No changes.
+
+Version 1.6.3beta01 [April 25, 2013]
+ Revised stack marking in arm/filter_neon.S and configure.ac.
+ Ensure that NEON filter stuff is completely disabled when switched 'off'.
+ Previously the ARM NEON specific files were still built if the option
+ was switched 'off' as opposed to being explicitly disabled.
+
+Version 1.6.3beta02 [April 26, 2013]
+ Test for 'arm*' not just 'arm' in the host_cpu configure variable.
+ Rebuilt the configure scripts.
+
+Version 1.6.3beta03 [April 30, 2013]
+ Expanded manual paragraph about writing private chunks, particularly
+ the need to call png_set_keep_unknown_chunks() when writing them.
+ Avoid dereferencing NULL pointer possibly returned from
+ png_create_write_struct() (Andrew Church).
+
+Version 1.6.3beta05 [May 9, 2013]
+ Calculate our own zlib windowBits when decoding rather than trusting the
+ CMF bytes in the PNG datastream.
+ Added an option to force maximum window size for inflating, which was
+ the behavior of libpng15 and earlier.
+ Added png-fix-itxt and png-fix-too-far-back to the built programs and
+ removed warnings from the source code and timepng that are revealed as
+ a result.
+ Detect wrong libpng versions linked to png-fix-too-far-back, which currently
+ only works with libpng versions that can be made to reliably fail when
+ the deflate data contains an out-of-window reference. This means only
+ 1.6 and later.
+ Fixed gnu issues: g++ needs a static_cast, gcc 4.4.7 has a broken warning
+ message which it is easier to work round than ignore.
+ Updated contrib/pngminus/pnm2png.c (Paul Stewart):
+ Check for EOF
+ Ignore "#" delimited comments in input file to pnm2png.c.
+ Fixed whitespace handling
+ Added a call to png_set_packing()
+ Initialize dimension values so if sscanf fails at least we have known
+ invalid values.
+ Attempt to detect configuration issues with png-fix-too-far-back, which
+ requires both the correct libpng and the correct zlib to function
+ correctly.
+ Check ZLIB_VERNUM for mismatches, enclose #error in quotes
+ Added information in the documentation about problems with and fixes for
+ the bad CRC and bad iTXt chunk situations.
+
+Version 1.6.3beta06 [May 12, 2013]
+ Allow contrib/pngminus/pnm2png.c to compile without WRITE_INVERT and
+ WRITE_PACK supported (writes error message that it can't read P1 or
+ P4 PBM files).
+ Improved png-fix-too-far-back usage message, added --suffix option.
+ Revised contrib/pngminim/*/makefile to generate pnglibconf.h with the
+ right zlib header files.
+ Separated CPPFLAGS and CFLAGS in contrib/pngminim/*/makefile
+
+Version 1.6.3beta07 [June 8, 2013]
+ Removed a redundant test in png_set_IHDR().
+ Added set(CMAKE_CONFIGURATION_TYPES ...) to CMakeLists.txt (Andrew Hundt)
+ Deleted set(CMAKE_BUILD_TYPE) block from CMakeLists.txt
+ Enclose the prototypes for the simplified write API in
+ #ifdef PNG_STDIO_SUPPORTED/#endif
+ Make ARM NEON support work at compile time (not just configure time).
+ This moves the test on __ARM_NEON__ into pngconf.h to avoid issues when
+ using a compiler that compiles for multiple architectures at one time.
+ Removed PNG_FILTER_OPTIMIZATIONS and PNG_ARM_NEON_SUPPORTED from
+ pnglibconf.h, allowing more of the decisions to be made internally
+ (pngpriv.h) during the compile. Without this, symbol prefixing is broken
+ under certain circumstances on ARM platforms. Now only the API parts of
+ the optimizations ('check' vs 'api') are exposed in the public header files
+ except that the new setting PNG_ARM_NEON_OPT documents how libpng makes the
+ decision about whether or not to use the optimizations.
+ Protect symbol prefixing against CC/CPPFLAGS/CFLAGS useage.
+ Previous iOS/Xcode fixes for the ARM NEON optimizations moved the test
+ on __ARM_NEON__ from configure time to compile time. This breaks symbol
+ prefixing because the definition of the special png_init_filter_functions
+ call was hidden at configure time if the relevant compiler arguments are
+ passed in CFLAGS as opposed to CC. This change attempts to avoid all
+ the confusion that would result by declaring the init function even when
+ it is not used, so that it will always get prefixed.
+
+Version 1.6.3beta08 [June 18, 2013]
+ Revised libpng.3 so that "doclifter" can process it.
+
+Version 1.6.3beta09 [June 27, 2013]
+ Revised example.c to illustrate use of PNG_DEFAULT_sRGB and PNG_GAMMA_MAC_18
+ as parameters for png_set_gamma(). These have been available since
+ libpng-1.5.4.
+ Renamed contrib/tools/png-fix-too-far-back.c to pngfix.c and revised it
+ to check all compressed chunks known to libpng.
+
+Version 1.6.3beta10 [July 5, 2013]
+ Updated documentation to show default behavior of benign errors correctly.
+ Only compile ARM code when PNG_READ_SUPPORTED is defined.
+ Fixed undefined behavior in contrib/tools/pngfix.c and added new strip
+ option. pngfix relied on undefined behavior and even a simple change from
+ gcc to g++ caused it to fail. The new strip option 'unsafe' has been
+ implemented and is the default if --max is given. Option names have
+ been clarified, with --strip=transform now stripping the bKGD chunk,
+ which was stripped previously with --strip=unused.
+ Added all documented chunk types to pngpriv.h
+ Unified pngfix.c source with libpng17.
+
+Version 1.6.3rc01 [July 11, 2013]
+ No changes.
+
+Version 1.6.3 [July 18, 2013]
+ Revised manual about changes in iTXt chunk handling made in libpng-1.6.0.
+ Added "/* SAFE */" comments in pngrutil.c and pngrtran.c where warnings
+ may be erroneously issued by code-checking applications.
+
+Version 1.6.4beta01 [August 21, 2013]
+ Added information about png_set_options() to the manual.
+ Delay calling png_init_filter_functions() until a row with nonzero filter
+ is found.
+
+Version 1.6.4beta02 [August 30, 2013]
+ Fixed inconsistent conditional compilation of png_chunk_unknown_handling()
+ prototype, definition, and usage. Made it depend on
+ PNG_HANDLE_AS_UNKNOWN_SUPPORTED everywhere.
+
+Version 1.6.4rc01 [September 5, 2013]
+ No changes.
+
+Version 1.6.4 [September 12, 2013]
+ No changes.
+
+Version 1.6.5 [September 14, 2013]
+ Removed two stray lines of code from arm/arm_init.c.
+
+Version 1.6.6 [September 16, 2013]
+ Removed two stray lines of code from arm/arm_init.c, again.
+
+Version 1.6.7beta01 [September 30, 2013]
+ Revised unknown chunk code to correct several bugs in the NO_SAVE_/NO_WRITE
+ combination
+ Allow HANDLE_AS_UNKNOWN to work when other options are configured off. Also
+ fixed the pngminim makefiles to work when $(MAKEFLAGS) contains stuff
+ which terminates the make options (as by default in recent versions of
+ Gentoo).
+ Avoid up-cast warnings in pngvalid.c. On ARM the alignment requirements of
+ png_modifier are greater than that of png_store and as a consequence
+ compilation of pngvalid.c results in a warning about increased alignment
+ requirements because of the bare cast to (png_modifier*). The code is safe,
+ because the pointer is known to point to a stack allocated png_modifier,
+ but this change avoids the warning.
+ Fixed default behavior of ARM_NEON_API. If the ARM NEON API option was
+ compiled without the CHECK option it defaulted to on, not off.
+ Check user callback behavior in pngunknown.c. Previous versions compiled
+ if SAVE_UNKNOWN was not available but did nothing since the callback
+ was never implemented.
+ Merged pngunknown.c with 1.7 version and back ported 1.7 improvements/fixes
+
+Version 1.6.7beta02 [October 12, 2013]
+ Made changes for compatibility with automake 1.14:
+ 1) Added the 'compile' program to the list of programs that must be cleaned
+ in autogen.sh
+ 2) Added 'subdir-objects' which causes .c files in sub-directories to be
+ compiled such that the corresponding .o files are also in the
+ sub-directory. This is because automake 1.14 warns that the
+ current behavior of compiling to the top level directory may be removed
+ in the future.
+ 3) Updated dependencies on pnglibconf.h to match the new .o locations and
+ added all the files in contrib/libtests and contrib/tools that depend
+ on pnglibconf.h
+ 4) Added 'BUILD_SOURCES = pnglibconf.h'; this is the automake recommended
+ way of handling the dependencies of sources that are machine generated;
+ unfortunately it only works if the user does 'make all' or 'make check',
+ so the dependencies (3) are still required.
+ Cleaned up (char*) casts of zlib messages. The latest version of the Intel C
+ compiler complains about casting a string literal as (char*), so copied the
+ treatment of z_const from the library code into pngfix.c
+ Simplified error message code in pngunknown. The simplification has the
+ useful side effect of avoiding a bogus warning generated by the latest
+ version of the Intel C compiler (it objects to
+ condition ? string-literal : string-literal).
+ Make autogen.sh work with automake 1.13 as well as 1.14. Do this by always
+ removing the 1.14 'compile' script but never checking for it.
+
+Version 1.6.7beta03 [October 19, 2013]
+ Added ARMv8 support (James Yu <james.yu at linaro.org>). Added file
+ arm/filter_neon_intrinsics.c; enable with -mfpu=neon.
+ Revised pngvalid to generate size images with as many filters as it can
+ manage, limited by the number of rows.
+ Cleaned up ARM NEON compilation handling. The tests are now in pngpriv.h
+ and detect the broken GCC compilers.
+
+Version 1.6.7beta04 [October 26, 2013]
+ Allow clang derived from older GCC versions to use ARM intrinsics. This
+ causes all clang builds that use -mfpu=neon to use the intrinsics code,
+ not the assembler code. This has only been tested on iOS 7. It may be
+ necessary to exclude some earlier clang versions but this seems unlikely.
+ Changed NEON implementation selection mechanism. This allows assembler
+ or intrinsics to be turned on at compile time during the build by defining
+ PNG_ARM_NEON_IMPLEMENTATION to the correct value (2 or 1). This macro
+ is undefined by default and the build type is selected in pngpriv.h.
+
+Version 1.6.7rc01 [November 2, 2013]
+ No changes.
+
+Version 1.6.7rc02 [November 7, 2013]
+ Fixed #include in filter_neon_intrinsics.c and ctype macros. The ctype char
+ checking macros take an unsigned char argument, not a signed char.
+
+Version 1.6.7 [November 14, 2013]
+ No changes.
+
+Version 1.6.8beta01 [November 24, 2013]
+ Moved prototype for png_handle_unknown() in pngpriv.h outside of
+ the #ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED/#endif block.
+ Added "-Wall" to CFLAGS in contrib/pngminim/*/makefile
+ Conditionally compile some unused functions reported by -Wall in
+ pngminim.
+ Fixed 'minimal' builds. Various obviously useful minimal configurations
+ don't build because of missing contrib/libtests test programs and
+ overly complex dependencies in scripts/pnglibconf.dfa. This change
+ adds contrib/conftest/*.dfa files that can be used in automatic build
+ scripts to ensure that these configurations continue to build.
+ Enabled WRITE_INVERT and WRITE_PACK in contrib/pngminim/encoder.
+ Fixed pngvalid 'fail' function declaration on the Intel C Compiler.
+ This reverts to the previous 'static' implementation and works round
+ the 'unused static function' warning by using PNG_UNUSED().
+
+Version 1.6.8beta02 [November 30, 2013]
+ Removed or marked PNG_UNUSED some harmless "dead assignments" reported
+ by clang scan-build.
+ Changed tabs to 3 spaces in png_debug macros and changed '"%s"m'
+ to '"%s" m' to improve portability among compilers.
+ Changed png_free_default() to free() in pngtest.c
+
+Version 1.6.8rc01 [December 12, 2013]
+ Tidied up pngfix inits and fixed pngtest no-write builds.
+
+Version 1.6.8rc02 [December 14, 2013]
+ Handle zero-length PLTE chunk or NULL palette with png_error()
+ instead of png_chunk_report(), which by default issues a warning
+ rather than an error, leading to later reading from a NULL pointer
+ (png_ptr->palette) in png_do_expand_palette(). This is CVE-2013-6954
+ and VU#650142. Libpng-1.6.1 through 1.6.7 are vulnerable.
+ Libpng-1.6.0 and earlier do not have this bug.
+
+Version 1.6.8 [December 19, 2013]
+ No changes.
+
+Version 1.6.9beta01 [December 26, 2013]
+ Bookkeeping: Moved functions around (no changes). Moved transform
+ function definitions before the place where they are called so that
+ they can be made static. Move the intrapixel functions and the
+ grayscale palette builder out of the png?tran.c files. The latter
+ isn't a transform function and is no longer used internally, and the
+ former MNG specific functions are better placed in pngread/pngwrite.c
+ Made transform implementation functions static. This makes the internal
+ functions called by png_do_{read|write}_transformations static. On an
+ x86-64 DLL build (Gentoo Linux) this reduces the size of the text
+ segment of the DLL by 1208 bytes, about 0.6%. It also simplifies
+ maintenance by removing the declarations from pngpriv.h and allowing
+ easier changes to the internal interfaces.
+ Rebuilt configure scripts with automake-1.14.1 and autoconf-2.69
+ in the tar distributions.
+
+Version 1.6.9beta02 [January 1, 2014]
+ Added checks for libpng 1.5 to pngvalid.c. This supports the use of
+ this version of pngvalid in libpng 1.5
+ Merged with pngvalid.c from libpng-1.7 changes to create a single
+ pngvalid.c
+ Removed #error macro from contrib/tools/pngfix.c (Thomas Klausner).
+ Merged pngrio.c, pngtrans.c, pngwio.c, and pngerror.c with libpng-1.7.0
+ Merged libpng-1.7.0 changes to make no-interlace configurations work
+ with test programs.
+ Revised pngvalid.c to support libpng 1.5, which does not support the
+ PNG_MAXIMUM_INFLATE_WINDOW option, so #define it out when appropriate in
+ pngvalid.c
+ Allow unversioned links created on install to be disabled in configure.
+ In configure builds 'make install' changes/adds links like png.h
+ and libpng.a to point to the newly installed, versioned, files (e.g.
+ libpng17/png.h and libpng17.a). Three new configure options and some
+ rearrangement of Makefile.am allow creation of these links to be disabled.
+
+Version 1.6.9beta03 [January 10, 2014]
+ Removed potentially misleading warning from png_check_IHDR().
+
+Version 1.6.9beta04 [January 20, 2014]
+ Updated scripts/makefile.* to use CPPFLAGS (Cosmin).
+ Added clang attribute support (Cosmin).
+
+Version 1.6.9rc01 [January 28, 2014]
+ No changes.
+
+Version 1.6.9rc02 [January 30, 2014]
+ Quiet an uninitialized memory warning from VC2013 in png_get_png().
+
+Version 1.6.9 [February 6, 2014]
+
+Version 1.6.10beta01 [February 9, 2014]
+ Backported changes from libpng-1.7.0beta30 and beta31:
+ Fixed a large number of instances where PNGCBAPI was omitted from
+ function definitions.
+ Added pngimage test program for png_read_png() and png_write_png()
+ with two new test scripts.
+ Removed dependence on !PNG_READ_EXPAND_SUPPORTED for calling
+ png_set_packing() in png_read_png().
+ Fixed combination of ~alpha with shift. On read invert alpha, processing
+ occurred after shift processing, which causes the final values to be
+ outside the range that should be produced by the shift. Reversing the
+ order on read makes the two transforms work together correctly and mirrors
+ the order used on write.
+ Do not read invalid sBIT chunks. Previously libpng only checked sBIT
+ values on write, so a malicious PNG writer could therefore cause
+ the read code to return an invalid sBIT chunk, which might lead to
+ application errors or crashes. Such chunks are now skipped (with
+ chunk_benign_error).
+ Make png_read_png() and png_write_png() prototypes in png.h depend
+ upon PNG_READ_SUPPORTED and PNG_WRITE_SUPPORTED.
+ Support builds with unsupported PNG_TRANSFORM_* values. All of the
+ PNG_TRANSFORM_* values are always defined in png.h and, because they
+ are used for both read and write in some cases, it is not reliable
+ to #if out ones that are totally unsupported. This change adds error
+ detection in png_read_image() and png_write_image() to do a
+ png_app_error() if the app requests something that cannot be done
+ and it adds corresponding code to pngimage.c to handle such options
+ by not attempting to test them.
+
+Version 1.6.10beta02 [February 23, 2014]
+ Moved redefines of png_error(), png_warning(), png_chunk_error(),
+ and png_chunk_warning() from pngpriv.h to png.h to make them visible
+ to libpng-calling applications.
+ Moved OS dependent code from arm/arm_init.c, to allow the included
+ implementation of the ARM NEON discovery function to be set at
+ build-time and provide sample implementations from the current code in the
+ contrib/arm-neon subdirectory. The __linux__ code has also been changed to
+ compile and link on Android by using /proc/cpuinfo, and the old linux code
+ is in contrib/arm-neon/linux-auxv.c. The new code avoids POSIX and Linux
+ dependencies apart from opening /proc/cpuinfo and is C90 compliant.
+ Check for info_ptr == NULL early in png_read_end() so we don't need to
+ run all the png_handle_*() and depend on them to return if info_ptr == NULL.
+ This improves the performance of png_read_end(png_ptr, NULL) and makes
+ it more robust against future programming errors.
+ Check for __has_extension before using it in pngconf.h, to
+ support older Clang versions (Jeremy Sequoia).
+ Treat CRC error handling with png_set_crc_action(), instead of with
+ png_set_benign_errors(), which has been the case since libpng-1.6.0beta18.
+ Use a user warning handler in contrib/gregbook/readpng2.c instead of default,
+ so warnings will be put on stderr even if libpng has CONSOLE_IO disabled.
+ Added png_ptr->process_mode = PNG_READ_IDAT_MODE in png_push_read_chunk
+ after recognizing the IDAT chunk, which avoids an infinite loop while
+ reading a datastream whose first IDAT chunk is of zero-length.
+ This fixes CERT VU#684412 and CVE-2014-0333.
+ Don't recognize known sRGB profiles as sRGB if they have been hacked,
+ but don't reject them and don't issue a copyright violation warning.
+
+Version 1.6.10beta03 [February 25, 2014]
+ Moved some documentation from png.h to libpng.3 and libpng-manual.txt
+ Minor editing of contrib/arm-neon/README and contrib/examples/*.c
+
+Version 1.6.10rc01 [February 27, 2014]
+ Fixed typos in the manual and in scripts/pnglibconf.dfa (CFLAGS -> CPPFLAGS
+ and PNG_USR_CONFIG -> PNG_USER_CONFIG).
+
+Version 1.6.10rc02 [February 28, 2014]
+ Removed unreachable return statement after png_chunk_error()
+ in pngrutil.c
+
+Version 1.6.10rc03 [March 4, 2014]
+ Un-deprecated png_data_freer().
+
+Version 1.6.10 [March 6, 2014]
+ No changes.
+
+Version 1.6.11beta01 [March 17, 2014]
+ Use "if (value != 0)" instead of "if (value)" consistently.
+ Changed ZlibSrcDir from 1.2.5 to 1.2.8 in projects/vstudio.
+ Moved configuration information from the manual to the INSTALL file.
+
+Version 1.6.11beta02 [April 6, 2014]
+ Removed #if/#else/#endif from inside two pow() calls in pngvalid.c because
+ they were handled improperly by Portland Group's PGI-14.1 - PGI-14.3
+ when using its "__builtin_pow()" function.
+ Silence 'unused parameter' build warnings (Cosmin Truta).
+ $(CP) is now used alongside $(RM_F). Also, use 'copy' instead of 'cp'
+ where applicable, and applied other minor makefile changes (Cosmin).
+ Don't warn about invalid dimensions exceeding user limits (Cosmin).
+ Allow an easy replacement of the default pre-built configuration
+ header with a custom header, via the make PNGLIBCONF_H_PREBUILT
+ macro (Cosmin).
+
+Version 1.6.11beta03 [April 6, 2014]
+ Fixed a typo in pngrutil.c, introduced in libpng-1.5.6, that interferes
+ with "blocky" expansion of sub-8-bit interlaced PNG files (Eric Huss).
+ Optionally use __builtin_bswap16() in png_do_swap().
+
+Version 1.6.11beta04 [April 19, 2014]
+ Made progressive reading of interlaced images consistent with the
+ behavior of the sequential reader and consistent with the manual, by
+ moving some code out of the PNG_READ_INTERLACING_SUPPORTED blocks. The
+ row_callback now receives the proper pass number and unexpanded rows, when
+ png_combine_row() isn't built or used, and png_set_interlace_handling()
+ is not called.
+ Allow PNG_sRGB_PROFILE_CHECKING = (-1) to mean no sRGB profile checking.
+
+Version 1.6.11beta05 [April 26, 2014]
+ Do not reject ICC V2 profiles that lack padding (Kai-Uwe Behrmann).
+ Relocated closing bracket of the sRGB profile test loop to avoid getting
+ "Not recognizing known sRGB profile that has been edited" warning for
+ ICC V2 profiles that lack the MD5 signature in the profile header.
+
+Version 1.6.11beta06 [May 19, 2014]
+ Added PNG_SKIP_sRGB_CHECK_PROFILE choice for png_set_option().
+
+Version 1.6.11rc01 [May 27, 2014]
+ No changes.
+
+Version 1.6.11rc02 [June 3, 2014]
+ Test ZLIB_VERNUM instead of PNG_ZLIB_VERNUM in contrib/tools/pngfix.c
+
+Version 1.6.11 [June 5, 2014]
+ No changes.
+
+Version 1.6.12rc01 [June 6, 2014]
+ Relocated new code from 1.6.11beta06 in png.c to a point after the
+ declarations (Max Stepin).
+
+Version 1.6.12rc02 [June 7, 2014]
+ Changed file permissions of contrib/tools/intgamma.sh,
+ test-driver, and compile from 0644 to 0755 (Cosmin).
+
+Version 1.6.12rc03 [June 8, 2014]
+ Ensure "__has_attribute()" macro exists before trying to use it with
+ old clang compilers (MacPorts Ticket #43939).
+
+Version 1.6.12 [June 12, 2014]
+ No changes.
+
+Version 1.6.13beta01 [July 4, 2014]
+ Quieted -Wsign-compare and -Wclobber compiler warnings in
+ contrib/pngminus/*.c
+ Added "(void) png_ptr;" where needed in contrib/gregbook to quiet
+ compiler complaints about unused pointers.
+ Split a long output string in contrib/gregbook/rpng2-x.c.
+ Added "PNG_SET_OPTION" requirement for sRGB chunk support to pnglibconf.dfa,
+ Needed for write-only support (John Bowler).
+ Changed "if defined(__ARM_NEON__)" to
+ "if (defined(__ARM_NEON__) || defined(__ARM_NEON))" (James Wu).
+ Fixed clang no-warning builds: png_digit was defined but never used.
+
+Version 1.6.13beta02 [July 21, 2014]
+ Fixed an incorrect separator ("/" should be "\") in scripts/makefile.vcwin32
+ (bug report from Wolfgang S. Kechel). Bug was introduced in libpng-1.6.11.
+ Also fixed makefile.bc32, makefile.bor, makefile.msc, makefile.intel, and
+ makefile.tc3 similarly.
+
+Version 1.6.13beta03 [August 3, 2014]
+ Removed scripts/makefile.elf. It has not worked since libpng-1.5.0beta14
+ due to elimination of the PNG_FUNCTION_EXPORT and PNG_DATA_EXPORT
+ definitions from pngconf.h.
+ Ensure that CMakeLists.txt makes the target "lib" directory before making
+ symbolic link into it (SourceForge bug report #226 by Rolf Timmermans).
+
+Version 1.6.13beta04 [August 8, 2014]
+ Added opinion that the ECCN (Export Control Classification Number) for
+ libpng is EAR99 to the README file.
+ Eliminated use of "$<" in makefile explicit rules, when copying
+ $PNGLIBCONF_H_PREBUILT. This does not work on some versions of make;
+ bug introduced in libpng version 1.6.11.
+
+Version 1.6.13rc01 [August 14, 2014]
+ Made "ccopts" agree with "CFLAGS" in scripts/makefile.hp* and makefile.*sunu
+
+Version 1.6.13 [August 21, 2014]
+ No changes.
+
+Version 1.6.14beta01 [September 14, 2014]
+ Guard usage of png_ptr->options with #ifdef PNG_SET_OPTION_SUPPORTED.
+ Do not build contrib/tools/pngfix.c when PNG_SETJMP_NOT_SUPPORTED,
+ to allow "make" to complete without setjmp support (bug report by
+ Claudio Fontana)
+ Add "#include <setjmp.h>" to contrib/tools/pngfix.c (John Bowler)
+
+Version 1.6.14beta02 [September 18, 2014]
+ Use nanosleep() instead of usleep() in contrib/gregbook/rpng2-x.c
+ because usleep() is deprecated.
+ Define usleep() in contrib/gregbook/rpng2-x.c if not already defined
+ in unistd.h and nanosleep() is not available; fixes error introduced
+ in libpng-1.6.13.
+ Disable floating point exception handling in pngvalid.c when
+ PNG_FLOATING_ARITHMETIC is not supported (bug report by "zootus
+ at users.sourceforge.net").
+
+Version 1.6.14beta03 [September 19, 2014]
+ Define FE_DIVBYZERO, FE_INVALID, and FE_OVERFLOW in pngvalid.c if not
+ already defined. Revert floating point exception handling in pngvalid.c
+ to version 1.6.14beta01 behavior.
+
+Version 1.6.14beta04 [September 27, 2014]
+ Fixed incorrect handling of the iTXt compression flag in pngrutil.c
+ (bug report by Shunsaku Hirata). Bug was introduced in libpng-1.6.0.
+
+Version 1.6.14beta05 [October 1, 2014]
+ Added "option READ_iCCP enables READ_COMPRESSED_TEXT" to pnglibconf.dfa
+
+Version 1.6.14beta06 [October 5, 2014]
+ Removed unused "text_len" parameter from private function png_write_zTXt().
+ Conditionally compile some code in png_deflate_claim(), when
+ PNG_WARNINGS_SUPPORTED and PNG_ERROR_TEXT_SUPPORTED are disabled.
+ Replaced repeated code in pngpread.c with PNG_PUSH_SAVE_BUFFER_IF_FULL.
+ Added "chunk iTXt enables TEXT" and "chunk zTXt enables TEXT"
+ to pnglibconf.dfa.
+ Removed "option READ_COMPRESSED_TEXT enables READ_TEXT" from pnglibconf.dfa,
+ to make it possible to configure a libpng that supports iCCP but not TEXT.
+
+Version 1.6.14beta07 [October 7, 2014]
+ Removed "option WRITE_COMPRESSED_TEXT enables WRITE_TEXT" from pnglibconf.dfa
+ Only mark text chunks as written after successfully writing them.
+
+Version 1.6.14rc01 [October 15, 2014]
+ Fixed some typos in comments.
+
+Version 1.6.14rc02 [October 17, 2014]
+ Changed png_convert_to_rfc_1123() to png_convert_to_rfc_1123_buffer()
+ in the manual, to reflect the change made in libpng-1.6.0.
+ Updated README file to explain that direct access to the png_struct
+ and info_struct members has not been permitted since libpng-1.5.0.
+
+Version 1.6.14 [October 23, 2014]
+ No changes.
+
+Version 1.6.15beta01 [October 29, 2014]
+ Changed "if (!x)" to "if (x == 0)" and "if (x)" to "if (x != 0)"
+ Simplified png_free_data().
+ Added missing "ptr = NULL" after some instances of png_free().
+
+Version 1.6.15beta02 [November 1, 2014]
+ Changed remaining "if (!x)" to "if (x == 0)" and "if (x)" to "if (x != 0)"
+
+Version 1.6.15beta03 [November 3, 2014]
+ Added PNG_USE_ARM_NEON configuration flag (Marcin Juszkiewicz).
+
+Version 1.6.15beta04 [November 4, 2014]
+ Removed new PNG_USE_ARM_NEON configuration flag and made a one-line
+ revision to configure.ac to support ARM on aarch64 instead (John Bowler).
+
+Version 1.6.15beta05 [November 5, 2014]
+ Use png_get_libpng_ver(NULL) instead of PNG_LIBPNG_VER_STRING in
+ example.c, pngtest.c, and applications in the contrib directory.
+ Avoid out-of-bounds memory access in png_user_version_check().
+ Simplified and future-proofed png_user_version_check().
+ Fixed GCC unsigned int->float warnings. Various versions of GCC
+ seem to generate warnings when an unsigned value is implicitly
+ converted to double. This is probably a GCC bug but this change
+ avoids the issue by explicitly converting to (int) where safe.
+ Free all allocated memory in pngimage. The file buffer cache was left
+ allocated at the end of the program, harmless but it causes memory
+ leak reports from clang.
+ Fixed array size calculations to avoid warnings. At various points
+ in the code the number of elements in an array is calculated using
+ sizeof. This generates a compile time constant of type (size_t) which
+ is then typically assigned to an (unsigned int) or (int). Some versions
+ of GCC on 64-bit systems warn about the apparent narrowing, even though
+ the same compiler does apparently generate the correct, in-range,
+ numeric constant. This adds appropriate, safe, casts to make the
+ warnings go away.
+
+Version 1.6.15beta06 [November 6, 2014]
+ Reverted use png_get_libpng_ver(NULL) instead of PNG_LIBPNG_VER_STRING
+ in the manual, example.c, pngtest.c, and applications in the contrib
+ directory. It was incorrect advice.
+
+Version 1.6.15beta07 [November 7, 2014]
+ Removed #ifdef PNG_16BIT_SUPPORTED/#endif around png_product2(); it is
+ needed by png_reciprocal2().
+ Added #ifdef PNG_16BIT_SUPPORTED/#endif around png_log16bit() and
+ png_do_swap().
+ Changed all "#endif /* PNG_FEATURE_SUPPORTED */" to "#endif /* FEATURE */"
+
+Version 1.6.15beta08 [November 8, 2014]
+ More housecleaning in *.h
+
+Version 1.6.15rc01 [November 13, 2014]
+
+Version 1.6.15rc02 [November 14, 2014]
+ The macros passed in the command line to Borland make were ignored if
+ similarly-named macros were already defined in makefiles. This behavior
+ is different from POSIX make and other make programs. Surround the
+ macro definitions with ifndef guards (Cosmin).
+
+Version 1.6.15rc03 [November 16, 2014]
+ Added "-D_CRT_SECURE_NO_WARNINGS" to CFLAGS in scripts/makefile.vcwin32.
+ Removed the obsolete $ARCH variable from scripts/makefile.darwin.
+
+Version 1.6.15 [November 20, 2014]
+ No changes.
+
+Version 1.6.16beta01 [December 14, 2014]
+ Added ".align 2" to arm/filter_neon.S to support old GAS assemblers that
+ don't do alignment correctly.
+ Revised Makefile.am and scripts/symbols.dfn to work with MinGW/MSYS
+ (Bob Friesenhahn).
+
+Version 1.6.16beta02 [December 15, 2014]
+ Revised Makefile.am and scripts/*.dfn again to work with MinGW/MSYS;
+ renamed scripts/*.dfn to scripts/*.c (John Bowler).
+
+Version 1.6.16beta03 [December 21, 2014]
+ Quiet a "comparison always true" warning in pngstest.c (John Bowler).
+
+Version 1.6.16rc01 [December 21, 2014]
+ Restored a test on width that was removed from png.c at libpng-1.6.9
+ (Bug report by Alex Eubanks, CVE-2015-0973).
+
+Version 1.6.16rc02 [December 21, 2014]
+ Undid the update to pngrutil.c in 1.6.16rc01.
+
+Version 1.6.16rc03 [December 21, 2014]
+ Fixed an overflow in png_combine_row() with very wide interlaced images
+ (Bug report and fix by John Bowler, CVE-2014-9495).
+
+Version 1.6.16 [December 22, 2014]
+ No changes.
+
+Version 1.6.17beta01 [January 29, 2015]
+ Removed duplicate PNG_SAFE_LIMITS_SUPPORTED handling from pngconf.h
+ Corrected the width limit calculation in png_check_IHDR().
+ Removed user limits from pngfix. Also pass NULL pointers to
+ png_read_row to skip the unnecessary row de-interlace stuff.
+ Added testing of png_set_packing() to pngvalid.c
+ Regenerated configure scripts in the *.tar distributions with libtool-2.4.4
+ Implement previously untested cases of libpng transforms in pngvalid.c
+ Fixed byte order in 2-byte filler, in png_do_read_filler().
+ Made the check for out-of-range values in png_set_tRNS() detect
+ values that are exactly 2^bit_depth, and work on 16-bit platforms.
+ Merged some parts of libpng-1.6.17beta01 and libpng-1.7.0beta47.
+ Added #ifndef __COVERITY__ where needed in png.c, pngrutil.c and
+ pngset.c to avoid warnings about dead code.
+ Added "& 0xff" to many instances of expressions that are typecast
+ to (png_byte), to avoid Coverity gripes.
+
+Version 1.6.17beta02 [February 7, 2015]
+ Work around one more Coverity-scan dead-code warning.
+ Do not build png_product2() when it is unused.
+
+Version 1.6.17beta03 [February 17, 2015]
+ Display user limits in the output from pngtest.
+ Eliminated the PNG_SAFE_LIMITS macro and restored the 1-million-column
+ and 1-million-row default limits in pnglibconf.dfa, that can be reset
+ by the user at build time or run time. This provides a more robust
+ defense against DOS and as-yet undiscovered overflows.
+
+Version 1.6.17beta04 [February 21, 2015]
+ Added PNG_WRITE_CUSTOMIZE_COMPRESSION_SUPPORTED macro, on by default.
+ Allow user to call png_get_IHDR() with NULL arguments (Reuben Hawkins).
+ Rebuilt configure scripts with automake-1.15 and libtool-2.4.6
+
+Version 1.6.17beta05 [February 25, 2015]
+ Restored compiling of png_reciprocal2 with PNG_NO_16BIT.
+
+Version 1.6.17beta06 [February 27, 2015]
+ Moved png_set_filter() prototype into a PNG_WRITE_SUPPORTED block
+ of png.h.
+ Avoid runtime checks when converting integer to png_byte with
+ Visual Studio (Sergey Kosarevsky)
+
+Version 1.6.17rc01 [March 4, 2015]
+ No changes.
+
+Version 1.6.17rc02 [March 9, 2015]
+ Removed some comments that the configure script did not handle
+ properly from scripts/pnglibconf.dfa and pnglibconf.h.prebuilt.
+ Free the unknown_chunks structure even when it contains no data.
+
+Version 1.6.17rc03 [March 12, 2015]
+ Updated CMakeLists.txt to add OSX framework, change YES/NO to ON/OFF
+ for consistency, and remove some useless tests (Alexey Petruchik).
+
+Version 1.6.17rc04 [March 16, 2015]
+ Remove pnglibconf.h, pnglibconf.c, and pnglibconf.out instead of
+ pnglibconf.* in "make clean" (Cosmin).
+ Fix bug in calculation of maxbits, in png_write_sBIT, introduced
+ in libpng-1.6.17beta01 (John Bowler).
+
+Version 1.6.17rc05 [March 21, 2015]
+ Define PNG_FILTER_* and PNG_FILTER_VALUE_* in png.h even when WRITE
+ is not supported (John Bowler). This fixes an error introduced in
+ libpng-1.6.17beta06.
+ Reverted "& 0xff" additions of version 1.6.17beta01. Libpng passes
+ the Coverity scan without them.
+
+Version 1.6.17rc06 [March 23, 2015]
+ Remove pnglibconf.dfn and pnglibconf.pre with "make clean".
+ Reformatted some "&0xff" instances to "& 0xff".
+ Fixed simplified 8-bit-linear to sRGB alpha. The calculated alpha
+ value was wrong. It's not clear if this affected the final stored
+ value; in the obvious code path the upper and lower 8-bits of the
+ alpha value were identical and the alpha was truncated to 8-bits
+ rather than dividing by 257 (John Bowler).
+
+Version 1.6.17 [March 26, 2015]
+ No changes.
+
+Send comments/corrections/commendations to png-mng-implement at lists.sf.net
+(subscription required; visit
+https://lists.sourceforge.net/lists/listinfo/png-mng-implement
+to subscribe)
+or to glennrp at users.sourceforge.net
+
+Glenn R-P
--- /dev/null
+
+Installing libpng
+
+Contents
+
+ I. Simple installation
+ II. Rebuilding the configure scripts
+ III. Using scripts/makefile*
+ IV. Using cmake
+ V. Directory structure
+ VI. Building with project files
+ VII. Building with makefiles
+VIII. Configuring libpng for 16-bit platforms
+ IX. Configuring for DOS
+ X. Configuring for Medium Model
+ XI. Prepending a prefix to exported symbols
+ XII. Configuring for compiler xxx:
+XIII. Removing unwanted object code
+ XIV. Changes to the build and configuration of libpng in libpng-1.5.x
+ XV. Setjmp/longjmp issues
+ XVI. Other sources of information about libpng
+
+I. Simple installation
+
+On Unix/Linux and similar systems, you can simply type
+
+ ./configure [--prefix=/path]
+ make check
+ make install
+
+and ignore the rest of this document. "/path" is the path to the directory
+where you want to install the libpng "lib", "include", and "bin"
+subdirectories.
+
+If you downloaded a GIT clone, you will need to run ./autogen.sh before
+running ./configure, to create "configure" and "Makefile.in" which are
+not included in the GIT repository.
+
+Note that "configure" is only included in the "*.tar" distributions and not
+in the "*.zip" or "*.7z" distributions. If you downloaded one of those
+distributions, see "Building with project files" or "Building with makefiles",
+below.
+
+II. Rebuilding the configure scripts
+
+If configure does not work on your system, or if you have a need to
+change configure.ac or Makefile.am, and you have a reasonably
+up-to-date set of tools, running ./autogen.sh in a git clone before
+running ./configure may fix the problem. To be really sure that you
+aren't using any of the included pre-built scripts, you can do this:
+
+ ./configure --enable-maintainer-mode
+ make maintainer-clean
+ ./autogen.sh --maintainer --clean
+ ./autogen.sh --maintainer
+ ./configure [--prefix=/path] [other options]
+ make
+ make install
+ make check
+
+III. Using scripts/makefile*
+
+Instead, you can use one of the custom-built makefiles in the
+"scripts" directory
+
+ cp scripts/pnglibconf.h.prebuilt pnglibconf.h
+ cp scripts/makefile.system makefile
+ make test
+ make install
+
+The files that are presently available in the scripts directory
+are listed and described in scripts/README.txt.
+
+Or you can use one of the "projects" in the "projects" directory.
+
+Before installing libpng, you must first install zlib, if it
+is not already on your system. zlib can usually be found
+wherever you got libpng; otherwise go to http://zlib.net. You can place
+zlib in in the same directory as libpng or in another directory.
+
+If your system already has a preinstalled zlib you will still need
+to have access to the zlib.h and zconf.h include files that
+correspond to the version of zlib that's installed.
+
+If you wish to test with a particular zlib that is not first in the
+standard library search path, put ZLIBLIB, ZLIBINC, CPPFLAGS, LDFLAGS,
+and LD_LIBRARY_PATH in your environment before running "make test"
+or "make distcheck":
+
+ZLIBLIB=/path/to/lib export ZLIBLIB
+ZLIBINC=/path/to/include export ZLIBINC
+CPPFLAGS="-I$ZLIBINC" export CPPFLAGS
+LDFLAGS="-L$ZLIBLIB" export LDFLAGS
+LD_LIBRARY_PATH="$ZLIBLIB:$LD_LIBRARY_PATH" export LD_LIBRARY_PATH
+
+If you are using one of the makefile scripts, put ZLIBLIB and ZLIBINC
+in your environment and type "make ZLIBLIB=$ZLIBLIB ZLIBINC=$ZLIBINC test".
+
+IV. Using cmake
+
+If you want to use "cmake" (see www.cmake.org), type
+
+ cmake . -DCMAKE_INSTALL_PREFIX=/path
+ make
+ make install
+
+As when using the simple configure method described above, "/path" points to
+the installation directory where you want to put the libpng "lib", "include",
+and "bin" subdirectories.
+
+V. Directory structure
+
+You can rename the directories that you downloaded (they
+might be called "libpng-x.y.z" or "libpngNN" and "zlib-1.2.8"
+or "zlib128") so that you have directories called "zlib" and "libpng".
+
+Your directory structure should look like this:
+
+ .. (the parent directory)
+ libpng (this directory)
+ INSTALL (this file)
+ README
+ *.h, *.c => libpng source files
+ CMakeLists.txt => "cmake" script
+ configuration files:
+ configure.ac, configure, Makefile.am, Makefile.in,
+ autogen.sh, config.guess, ltmain.sh, missing, libpng.pc.in,
+ libpng-config.in, aclocal.m4, config.h.in, config.sub,
+ depcomp, install-sh, mkinstalldirs, test-pngtest.sh
+ contrib
+ arm-neon, conftest, examples, gregbook, libtests, pngminim,
+ pngminus, pngsuite, tools, visupng
+ projects
+ cbuilder5, owatcom, visualc71, vstudio, xcode
+ scripts
+ makefile.*
+ *.def (module definition files)
+ etc.
+ pngtest.png
+ etc.
+ zlib
+ README, *.h, *.c contrib, etc.
+
+If the line endings in the files look funny, you may wish to get the other
+distribution of libpng. It is available in both tar.gz (UNIX style line
+endings) and zip (DOS style line endings) formats.
+
+VI. Building with project files
+
+If you are building libpng with MSVC, you can enter the
+libpng projects\visualc71 or vstudio directory and follow the instructions
+in README.txt.
+
+Otherwise enter the zlib directory and follow the instructions in zlib/README,
+then come back here and run "configure" or choose the appropriate
+makefile.sys in the scripts directory.
+
+VII. Building with makefiles
+
+Copy the file (or files) that you need from the
+scripts directory into this directory, for example
+
+ MSDOS example: copy scripts\makefile.msc makefile
+ copy scripts\pnglibconf.h.prebuilt pnglibconf.h
+ UNIX example: cp scripts/makefile.std makefile
+ cp scripts/pnglibconf.h.prebuilt pnglibconf.h
+
+Read the makefile to see if you need to change any source or
+target directories to match your preferences.
+
+Then read pnglibconf.dfa to see if you want to make any configuration
+changes.
+
+Then just run "make" which will create the libpng library in
+this directory and "make test" which will run a quick test that reads
+the "pngtest.png" file and writes a "pngout.png" file that should be
+identical to it. Look for "9782 zero samples" in the output of the
+test. For more confidence, you can run another test by typing
+"pngtest pngnow.png" and looking for "289 zero samples" in the output.
+Also, you can run "pngtest -m contrib/pngsuite/*.png" and compare
+your output with the result shown in contrib/pngsuite/README.
+
+Most of the makefiles will allow you to run "make install" to
+put the library in its final resting place (if you want to
+do that, run "make install" in the zlib directory first if necessary).
+Some also allow you to run "make test-installed" after you have
+run "make install".
+
+VIII. Configuring libpng for 16-bit platforms
+
+You will want to look into zconf.h to tell zlib (and thus libpng) that
+it cannot allocate more than 64K at a time. Even if you can, the memory
+won't be accessible. So limit zlib and libpng to 64K by defining MAXSEG_64K.
+
+IX. Configuring for DOS
+
+For DOS users who only have access to the lower 640K, you will
+have to limit zlib's memory usage via a png_set_compression_mem_level()
+call. See zlib.h or zconf.h in the zlib library for more information.
+
+X. Configuring for Medium Model
+
+Libpng's support for medium model has been tested on most of the popular
+compilers. Make sure MAXSEG_64K gets defined, USE_FAR_KEYWORD gets
+defined, and FAR gets defined to far in pngconf.h, and you should be
+all set. Everything in the library (except for zlib's structure) is
+expecting far data. You must use the typedefs with the p or pp on
+the end for pointers (or at least look at them and be careful). Make
+note that the rows of data are defined as png_bytepp, which is
+an "unsigned char far * far *".
+
+XI. Prepending a prefix to exported symbols
+
+Starting with libpng-1.6.0, you can configure libpng (when using the
+"configure" script) to prefix all exported symbols by means of the
+configuration option "--with-libpng-prefix=FOO_", where FOO_ can be any
+string beginning with a letter and containing only uppercase
+and lowercase letters, digits, and the underscore (i.e., a C language
+identifier). This creates a set of macros in pnglibconf.h, so this is
+transparent to applications; their function calls get transformed by
+the macros to use the modified names.
+
+XII. Configuring for compiler xxx:
+
+All includes for libpng are in pngconf.h. If you need to add, change
+or delete an include, this is the place to do it.
+The includes that are not needed outside libpng are placed in pngpriv.h,
+which is only used by the routines inside libpng itself.
+The files in libpng proper only include pngpriv.h and png.h, which
+in turn includes pngconf.h and, as of libpng-1.5.0, pnglibconf.h.
+As of libpng-1.5.0, pngpriv.h also includes three other private header
+files, pngstruct.h, pnginfo.h, and pngdebug.h, which contain material
+that previously appeared in the public headers.
+
+XIII. Removing unwanted object code
+
+There are a bunch of #define's in pngconf.h that control what parts of
+libpng are compiled. All the defines end in _SUPPORTED. If you are
+never going to use a capability, you can change the #define to #undef
+before recompiling libpng and save yourself code and data space, or
+you can turn off individual capabilities with defines that begin with
+PNG_NO_.
+
+In libpng-1.5.0 and later, the #define's are in pnglibconf.h instead.
+
+You can also turn all of the transforms and ancillary chunk capabilities
+off en masse with compiler directives that define
+PNG_NO_READ[or WRITE]_TRANSFORMS, or PNG_NO_READ[or WRITE]_ANCILLARY_CHUNKS,
+or all four, along with directives to turn on any of the capabilities that
+you do want. The PNG_NO_READ[or WRITE]_TRANSFORMS directives disable the
+extra transformations but still leave the library fully capable of reading
+and writing PNG files with all known public chunks. Use of the
+PNG_NO_READ[or WRITE]_ANCILLARY_CHUNKS directive produces a library
+that is incapable of reading or writing ancillary chunks. If you are
+not using the progressive reading capability, you can turn that off
+with PNG_NO_PROGRESSIVE_READ (don't confuse this with the INTERLACING
+capability, which you'll still have).
+
+All the reading and writing specific code are in separate files, so the
+linker should only grab the files it needs. However, if you want to
+make sure, or if you are building a stand alone library, all the
+reading files start with "pngr" and all the writing files start with "pngw".
+The files that don't match either (like png.c, pngtrans.c, etc.)
+are used for both reading and writing, and always need to be included.
+The progressive reader is in pngpread.c
+
+If you are creating or distributing a dynamically linked library (a .so
+or DLL file), you should not remove or disable any parts of the library,
+as this will cause applications linked with different versions of the
+library to fail if they call functions not available in your library.
+The size of the library itself should not be an issue, because only
+those sections that are actually used will be loaded into memory.
+
+XIV. Changes to the build and configuration of libpng in libpng-1.5.x
+
+Details of internal changes to the library code can be found in the CHANGES
+file and in the GIT repository logs. These will be of no concern to the vast
+majority of library users or builders; however, the few who configure libpng
+to a non-default feature set may need to change how this is done.
+
+There should be no need for library builders to alter build scripts if
+these use the distributed build support - configure or the makefiles -
+however, users of the makefiles may care to update their build scripts
+to build pnglibconf.h where the corresponding makefile does not do so.
+
+Building libpng with a non-default configuration has changed completely.
+The old method using pngusr.h should still work correctly even though the
+way pngusr.h is used in the build has been changed; however, library
+builders will probably want to examine the changes to take advantage of
+new capabilities and to simplify their build system.
+
+A. Specific changes to library configuration capabilities
+
+The exact mechanism used to control attributes of API functions has
+changed. A single set of operating system independent macro definitions
+is used and operating system specific directives are defined in
+pnglibconf.h
+
+As part of this the mechanism used to choose procedure call standards on
+those systems that allow a choice has been changed. At present this only
+affects certain Microsoft (DOS, Windows) and IBM (OS/2) operating systems
+running on Intel processors. As before, PNGAPI is defined where required
+to control the exported API functions; however, two new macros, PNGCBAPI
+and PNGCAPI, are used instead for callback functions (PNGCBAPI) and
+(PNGCAPI) for functions that must match a C library prototype (currently
+only png_longjmp_ptr, which must match the C longjmp function.) The new
+approach is documented in pngconf.h
+
+Despite these changes, libpng 1.5.0 only supports the native C function
+calling standard on those platforms tested so far (__cdecl on Microsoft
+Windows). This is because the support requirements for alternative
+calling conventions seem to no longer exist. Developers who find it
+necessary to set PNG_API_RULE to 1 should advise the mailing list
+(png-mng-implement) of this and library builders who use Openwatcom and
+therefore set PNG_API_RULE to 2 should also contact the mailing list.
+
+B. Changes to the configuration mechanism
+
+Prior to libpng-1.5.0 library builders who needed to configure libpng
+had either to modify the exported pngconf.h header file to add system
+specific configuration or had to write feature selection macros into
+pngusr.h and cause this to be included into pngconf.h by defining
+PNG_USER_CONFIG. The latter mechanism had the disadvantage that an
+application built without PNG_USER_CONFIG defined would see the
+unmodified, default, libpng API and thus would probably fail to link.
+
+These mechanisms still work in the configure build and in any makefile
+build that builds pnglibconf.h, although the feature selection macros
+have changed somewhat as described above. In 1.5.0, however, pngusr.h is
+processed only once, at the time the exported header file pnglibconf.h is
+built. pngconf.h no longer includes pngusr.h; therefore, pngusr.h is ignored
+after the build of pnglibconf.h and it is never included in an application
+build.
+
+The formerly used alternative of adding a list of feature macros to the
+CPPFLAGS setting in the build also still works; however, the macros will be
+copied to pnglibconf.h and this may produce macro redefinition warnings
+when the individual C files are compiled.
+
+All configuration now only works if pnglibconf.h is built from
+scripts/pnglibconf.dfa. This requires the program awk. Brian Kernighan
+(the original author of awk) maintains C source code of that awk and this
+and all known later implementations (often called by subtly different
+names - nawk and gawk for example) are adequate to build pnglibconf.h.
+The Sun Microsystems (now Oracle) program 'awk' is an earlier version
+and does not work; this may also apply to other systems that have a
+functioning awk called 'nawk'.
+
+Configuration options are now documented in scripts/pnglibconf.dfa. This
+file also includes dependency information that ensures a configuration is
+consistent; that is, if a feature is switched off, dependent features are
+also switched off. As a recommended alternative to using feature macros in
+pngusr.h a system builder may also define equivalent options in pngusr.dfa
+(or, indeed, any file) and add that to the configuration by setting
+DFA_XTRA to the file name. The makefiles in contrib/pngminim illustrate
+how to do this, and also illustrate a case where pngusr.h is still required.
+
+After you have built libpng, the definitions that were recorded in
+pnglibconf.h are available to your application (pnglibconf.h is included
+in png.h and gets installed alongside png.h and pngconf.h in your
+$PREFIX/include directory). Do not edit pnglibconf.h after you have built
+libpng, because than the settings would not accurately reflect the settings
+that were used to build libpng.
+
+XV. Setjmp/longjmp issues
+
+Libpng uses setjmp()/longjmp() for error handling. Unfortunately setjmp()
+is known to be not thread-safe on some platforms and we don't know of
+any platform where it is guaranteed to be thread-safe. Therefore, if
+your application is going to be using multiple threads, you should
+configure libpng with PNG_NO_SETJMP in your pngusr.dfa file, with
+-DPNG_NO_SETJMP on your compile line, or with
+
+ #undef PNG_SETJMP_SUPPORTED
+
+in your pnglibconf.h or pngusr.h.
+
+Starting with libpng-1.6.0, the library included a "simplified API".
+This requires setjmp/longjmp, so you must either build the library
+with PNG_SETJMP_SUPPORTED defined, or with PNG_SIMPLIFIED_READ_SUPPORTED
+and PNG_SIMPLIFIED_WRITE_SUPPORTED undefined.
+
+XVI. Other sources of information about libpng:
+
+Further information can be found in the README and libpng-manual.txt
+files, in the individual makefiles, in png.h, and the manual pages
+libpng.3 and png.5.
+
+Using the ./configure script -- 16 December 2002.
+=================================================
+
+The ./configure script should work compatibly with what scripts/makefile.*
+did, however there are some options you might need to add to configure
+explicitly, which previously was done semi-automatically (if you didn't edit
+scripts/makefile.* yourself, that is)
+
+CFLAGS="-Wall -O -funroll-loops \
+-malign-loops=2 -malign-functions=2" ./configure --prefix=/usr/include \
+--with-pkgconfigdir=/usr/lib/pkgconfig --includedir=/usr/include
+
+You can alternatively specify --includedir=/usr/include, /usr/local/include,
+/usr/include/libpng16, or whatever.
+
+If you find that the configure script is out-of-date or is not supporting
+your platform properly, try running autogen.sh to regenerate "configure",
+"Makefile.in", and the other configuration files. Then try configure again.
+
--- /dev/null
+
+This copy of the libpng notices is provided for your convenience. In case of
+any discrepancy between this copy and the notices in the file png.h that is
+included in the libpng distribution, the latter shall prevail.
+
+COPYRIGHT NOTICE, DISCLAIMER, and LICENSE:
+
+If you modify libpng you may insert additional notices immediately following
+this sentence.
+
+This code is released under the libpng license.
+
+libpng versions 1.2.6, August 15, 2004, through 1.6.17, March 26, 2015, are
+Copyright (c) 2004, 2006-2015 Glenn Randers-Pehrson, and are
+distributed according to the same disclaimer and license as libpng-1.2.5
+with the following individual added to the list of Contributing Authors
+
+ Cosmin Truta
+
+libpng versions 1.0.7, July 1, 2000, through 1.2.5 - October 3, 2002, are
+Copyright (c) 2000-2002 Glenn Randers-Pehrson, and are
+distributed according to the same disclaimer and license as libpng-1.0.6
+with the following individuals added to the list of Contributing Authors
+
+ Simon-Pierre Cadieux
+ Eric S. Raymond
+ Gilles Vollant
+
+and with the following additions to the disclaimer:
+
+ There is no warranty against interference with your enjoyment of the
+ library or against infringement. There is no warranty that our
+ efforts or the library will fulfill any of your particular purposes
+ or needs. This library is provided with all faults, and the entire
+ risk of satisfactory quality, performance, accuracy, and effort is with
+ the user.
+
+libpng versions 0.97, January 1998, through 1.0.6, March 20, 2000, are
+Copyright (c) 1998, 1999 Glenn Randers-Pehrson, and are
+distributed according to the same disclaimer and license as libpng-0.96,
+with the following individuals added to the list of Contributing Authors:
+
+ Tom Lane
+ Glenn Randers-Pehrson
+ Willem van Schaik
+
+libpng versions 0.89, June 1996, through 0.96, May 1997, are
+Copyright (c) 1996, 1997 Andreas Dilger
+Distributed according to the same disclaimer and license as libpng-0.88,
+with the following individuals added to the list of Contributing Authors:
+
+ John Bowler
+ Kevin Bracey
+ Sam Bushell
+ Magnus Holmgren
+ Greg Roelofs
+ Tom Tanner
+
+libpng versions 0.5, May 1995, through 0.88, January 1996, are
+Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
+
+For the purposes of this copyright and license, "Contributing Authors"
+is defined as the following set of individuals:
+
+ Andreas Dilger
+ Dave Martindale
+ Guy Eric Schalnat
+ Paul Schmidt
+ Tim Wegner
+
+The PNG Reference Library is supplied "AS IS". The Contributing Authors
+and Group 42, Inc. disclaim all warranties, expressed or implied,
+including, without limitation, the warranties of merchantability and of
+fitness for any purpose. The Contributing Authors and Group 42, Inc.
+assume no liability for direct, indirect, incidental, special, exemplary,
+or consequential damages, which may result from the use of the PNG
+Reference Library, even if advised of the possibility of such damage.
+
+Permission is hereby granted to use, copy, modify, and distribute this
+source code, or portions hereof, for any purpose, without fee, subject
+to the following restrictions:
+
+1. The origin of this source code must not be misrepresented.
+
+2. Altered versions must be plainly marked as such and must not
+ be misrepresented as being the original source.
+
+3. This Copyright notice may not be removed or altered from any
+ source or altered source distribution.
+
+The Contributing Authors and Group 42, Inc. specifically permit, without
+fee, and encourage the use of this source code as a component to
+supporting the PNG file format in commercial products. If you use this
+source code in a product, acknowledgment is not required but would be
+appreciated.
+
+
+A "png_get_copyright" function is available, for convenient use in "about"
+boxes and the like:
+
+ printf("%s",png_get_copyright(NULL));
+
+Also, the PNG logo (in PNG format, of course) is supplied in the
+files "pngbar.png" and "pngbar.jpg (88x31) and "pngnow.png" (98x31).
+
+Libpng is OSI Certified Open Source Software. OSI Certified Open Source is a
+certification mark of the Open Source Initiative.
+
+Glenn Randers-Pehrson
+glennrp at users.sourceforge.net
+March 26, 2015
--- /dev/null
+README for libpng version 1.6.17 - March 26, 2015 (shared library 16.0)
+See the note about version numbers near the top of png.h
+
+See INSTALL for instructions on how to install libpng.
+
+Libpng comes in several distribution formats. Get libpng-*.tar.gz or
+libpng-*.tar.xz or if you want UNIX-style line endings in the text files,
+or lpng*.7z or lpng*.zip if you want DOS-style line endings.
+
+Version 0.89 was the first official release of libpng. Don't let the
+fact that it's the first release fool you. The libpng library has been in
+extensive use and testing since mid-1995. By late 1997 it had
+finally gotten to the stage where there hadn't been significant
+changes to the API in some time, and people have a bad feeling about
+libraries with versions < 1.0. Version 1.0.0 was released in
+March 1998.
+
+****
+Note that some of the changes to the png_info structure render this
+version of the library binary incompatible with libpng-0.89 or
+earlier versions if you are using a shared library. The type of the
+"filler" parameter for png_set_filler() has changed from png_byte to
+png_uint_32, which will affect shared-library applications that use
+this function.
+
+To avoid problems with changes to the internals of png info_struct,
+new APIs have been made available in 0.95 to avoid direct application
+access to info_ptr. These functions are the png_set_<chunk> and
+png_get_<chunk> functions. These functions should be used when
+accessing/storing the info_struct data, rather than manipulating it
+directly, to avoid such problems in the future.
+
+It is important to note that the APIs did not make current programs
+that access the info struct directly incompatible with the new
+library, through libpng-1.2.x. In libpng-1.4.x, which was meant to
+be a transitional release, members of the png_struct and the
+info_struct can still be accessed, but the compiler will issue a
+warning about deprecated usage. Since libpng-1.5.0, direct access
+to these structs is not allowed, and the definitions of the structs
+reside in private pngstruct.h and pnginfo.h header files that are not
+accessible to applications. It is strongly suggested that new
+programs use the new APIs (as shown in example.c and pngtest.c), and
+older programs be converted to the new format, to facilitate upgrades
+in the future.
+****
+
+Additions since 0.90 include the ability to compile libpng as a
+Windows DLL, and new APIs for accessing data in the info struct.
+Experimental functions include the ability to set weighting and cost
+factors for row filter selection, direct reads of integers from buffers
+on big-endian processors that support misaligned data access, faster
+methods of doing alpha composition, and more accurate 16->8 bit color
+conversion.
+
+The additions since 0.89 include the ability to read from a PNG stream
+which has had some (or all) of the signature bytes read by the calling
+application. This also allows the reading of embedded PNG streams that
+do not have the PNG file signature. As well, it is now possible to set
+the library action on the detection of chunk CRC errors. It is possible
+to set different actions based on whether the CRC error occurred in a
+critical or an ancillary chunk.
+
+The changes made to the library, and bugs fixed are based on discussions
+on the PNG-implement mailing list and not on material submitted
+privately to Guy, Andreas, or Glenn. They will forward any good
+suggestions to the list.
+
+For a detailed description on using libpng, read libpng-manual.txt. For
+examples of libpng in a program, see example.c and pngtest.c. For usage
+information and restrictions (what little they are) on libpng, see
+png.h. For a description on using zlib (the compression library used by
+libpng) and zlib's restrictions, see zlib.h
+
+I have included a general makefile, as well as several machine and
+compiler specific ones, but you may have to modify one for your own needs.
+
+You should use zlib 1.0.4 or later to run this, but it MAY work with
+versions as old as zlib 0.95. Even so, there are bugs in older zlib
+versions which can cause the output of invalid compression streams for
+some images. You will definitely need zlib 1.0.4 or later if you are
+taking advantage of the MS-DOS "far" structure allocation for the small
+and medium memory models. You should also note that zlib is a
+compression library that is useful for more things than just PNG files.
+You can use zlib as a drop-in replacement for fread() and fwrite() if
+you are so inclined.
+
+zlib should be available at the same place that libpng is, or at zlib.net.
+
+You may also want a copy of the PNG specification. It is available
+as an RFC, a W3C Recommendation, and an ISO/IEC Standard. You can find
+these at http://www.libpng.org/pub/png/documents/
+
+This code is currently being archived at libpng.sf.net in the
+[DOWNLOAD] area, and at ftp://ftp.simplesystems.org. If you can't find it
+in any of those places, e-mail me, and I'll help you find it.
+
+I am not a lawyer, but I believe that the Export Control Classification
+Number (ECCN) for libpng is EAR99, which means not subject to export
+controls or International Traffic in Arms Regulations (ITAR) because it
+is open source, publicly available software, that does not contain any
+encryption software. See the EAR, paragraphs 734.3(b)(3) and 734.7(b).
+
+If you have any code changes, requests, problems, etc., please e-mail
+them to me. Also, I'd appreciate any make files or project files,
+and any modifications you needed to make to get libpng to compile,
+along with a #define variable to tell what compiler/system you are on.
+If you needed to add transformations to libpng, or wish libpng would
+provide the image in a different way, drop me a note (and code, if
+possible), so I can consider supporting the transformation.
+Finally, if you get any warning messages when compiling libpng
+(note: not zlib), and they are easy to fix, I'd appreciate the
+fix. Please mention "libpng" somewhere in the subject line. Thanks.
+
+This release was created and will be supported by myself (of course
+based in a large way on Guy's and Andreas' earlier work), and the PNG
+development group.
+
+Send comments/corrections/commendations to png-mng-implement at
+lists.sourceforge.net (subscription required; visit
+https://lists.sourceforge.net/lists/listinfo/png-mng-implement
+to subscribe) or to glennrp at users.sourceforge.net
+
+You can't reach Guy, the original libpng author, at the addresses
+given in previous versions of this document. He and Andreas will
+read mail addressed to the png-implement list, however.
+
+Please do not send general questions about PNG. Send them to
+png-mng-misc at lists.sf.net (subscription required; visit
+https://lists.sourceforge.net/lists/listinfo/png-mng-misc to
+subscribe). If you have a question about something
+in the PNG specification that is related to using libpng, send it
+to me. Send me any questions that start with "I was using libpng,
+and ...". If in doubt, send questions to me. I'll bounce them
+to others, if necessary.
+
+Please do not send suggestions on how to change PNG. We have
+been discussing PNG for nineteen years now, and it is official and
+finished. If you have suggestions for libpng, however, I'll
+gladly listen. Even if your suggestion is not used immediately,
+it may be used later.
+
+Files in this distribution:
+
+ ANNOUNCE => Announcement of this version, with recent changes
+ CHANGES => Description of changes between libpng versions
+ KNOWNBUG => List of known bugs and deficiencies
+ LICENSE => License to use and redistribute libpng
+ README => This file
+ TODO => Things not implemented in the current library
+ Y2KINFO => Statement of Y2K compliance
+ example.c => Example code for using libpng functions
+ libpng.3 => manual page for libpng (includes libpng-manual.txt)
+ libpng-manual.txt => Description of libpng and its functions
+ libpngpf.3 => manual page for libpng's private functions
+ png.5 => manual page for the PNG format
+ png.c => Basic interface functions common to library
+ png.h => Library function and interface declarations (public)
+ pngpriv.h => Library function and interface declarations (private)
+ pngconf.h => System specific library configuration (public)
+ pngstruct.h => png_struct declaration (private)
+ pnginfo.h => png_info struct declaration (private)
+ pngdebug.h => debugging macros (private)
+ pngerror.c => Error/warning message I/O functions
+ pngget.c => Functions for retrieving info from struct
+ pngmem.c => Memory handling functions
+ pngbar.png => PNG logo, 88x31
+ pngnow.png => PNG logo, 98x31
+ pngpread.c => Progressive reading functions
+ pngread.c => Read data/helper high-level functions
+ pngrio.c => Lowest-level data read I/O functions
+ pngrtran.c => Read data transformation functions
+ pngrutil.c => Read data utility functions
+ pngset.c => Functions for storing data into the info_struct
+ pngtest.c => Library test program
+ pngtest.png => Library test sample image
+ pngtrans.c => Common data transformation functions
+ pngwio.c => Lowest-level write I/O functions
+ pngwrite.c => High-level write functions
+ pngwtran.c => Write data transformations
+ pngwutil.c => Write utility functions
+ arm => Contains optimized code for the ARM platform
+ contrib => Contributions
+ examples => Example programs
+ gregbook => source code for PNG reading and writing, from
+ Greg Roelofs' "PNG: The Definitive Guide",
+ O'Reilly, 1999
+ libtests => Test programs
+ pngminim => Minimal decoder, encoder, and progressive decoder
+ programs demonstrating use of pngusr.dfa
+ pngminus => Simple pnm2png and png2pnm programs
+ pngsuite => Test images
+ tools => Various tools
+ visupng => Contains a MSVC workspace for VisualPng
+ projects => Contains project files and workspaces for
+ building a DLL
+ owatcom => Contains a WATCOM project for building libpng
+ visualc71 => Contains a Microsoft Visual C++ (MSVC)
+ workspace for building libpng and zlib
+ vstudio => Contains a Microsoft Visual C++ (MSVC)
+ workspace for building libpng and zlib
+ scripts => Directory containing scripts for building libpng:
+ (see scripts/README.txt for the list of scripts)
+
+Good luck, and happy coding.
+
+-Glenn Randers-Pehrson (current maintainer, since 1998)
+ Internet: glennrp at users.sourceforge.net
+
+-Andreas Eric Dilger (former maintainer, 1996-1997)
+ Internet: adilger at enel.ucalgary.ca
+ Web: http://www-mddsp.enel.ucalgary.ca/People/adilger/
+
+-Guy Eric Schalnat (original author and former maintainer, 1995-1996)
+ (formerly of Group 42, Inc)
+ Internet: gschal at infinet.com
--- /dev/null
+libpng-manual.txt - A description on how to use and modify libpng
+
+ libpng version 1.6.17 - March 26, 2015
+ Updated and distributed by Glenn Randers-Pehrson
+ <glennrp at users.sourceforge.net>
+ Copyright (c) 1998-2015 Glenn Randers-Pehrson
+
+ This document is released under the libpng license.
+ For conditions of distribution and use, see the disclaimer
+ and license in png.h
+
+ Based on:
+
+ libpng versions 0.97, January 1998, through 1.6.17 - March 26, 2015
+ Updated and distributed by Glenn Randers-Pehrson
+ Copyright (c) 1998-2015 Glenn Randers-Pehrson
+
+ libpng 1.0 beta 6 - version 0.96 - May 28, 1997
+ Updated and distributed by Andreas Dilger
+ Copyright (c) 1996, 1997 Andreas Dilger
+
+ libpng 1.0 beta 2 - version 0.88 - January 26, 1996
+ For conditions of distribution and use, see copyright
+ notice in png.h. Copyright (c) 1995, 1996 Guy Eric
+ Schalnat, Group 42, Inc.
+
+ Updated/rewritten per request in the libpng FAQ
+ Copyright (c) 1995, 1996 Frank J. T. Wojcik
+ December 18, 1995 & January 20, 1996
+
+ TABLE OF CONTENTS
+
+ I. Introduction
+ II. Structures
+ III. Reading
+ IV. Writing
+ V. Simplified API
+ VI. Modifying/Customizing libpng
+ VII. MNG support
+ VIII. Changes to Libpng from version 0.88
+ IX. Changes to Libpng from version 1.0.x to 1.2.x
+ X. Changes to Libpng from version 1.0.x/1.2.x to 1.4.x
+ XI. Changes to Libpng from version 1.4.x to 1.5.x
+ XII. Changes to Libpng from version 1.5.x to 1.6.x
+ XIII. Detecting libpng
+ XIV. Source code repository
+ XV. Coding style
+ XVI. Y2K Compliance in libpng
+
+I. Introduction
+
+This file describes how to use and modify the PNG reference library
+(known as libpng) for your own use. In addition to this
+file, example.c is a good starting point for using the library, as
+it is heavily commented and should include everything most people
+will need. We assume that libpng is already installed; see the
+INSTALL file for instructions on how to configure and install libpng.
+
+For examples of libpng usage, see the files "example.c", "pngtest.c",
+and the files in the "contrib" directory, all of which are included in
+the libpng distribution.
+
+Libpng was written as a companion to the PNG specification, as a way
+of reducing the amount of time and effort it takes to support the PNG
+file format in application programs.
+
+The PNG specification (second edition), November 2003, is available as
+a W3C Recommendation and as an ISO Standard (ISO/IEC 15948:2004 (E)) at
+<http://www.w3.org/TR/2003/REC-PNG-20031110/
+The W3C and ISO documents have identical technical content.
+
+The PNG-1.2 specification is available at
+<http://www.libpng.org/pub/png/documents/>. It is technically equivalent
+to the PNG specification (second edition) but has some additional material.
+
+The PNG-1.0 specification is available
+as RFC 2083 <http://www.libpng.org/pub/png/documents/> and as a
+W3C Recommendation <http://www.w3.org/TR/REC.png.html>.
+
+Some additional chunks are described in the special-purpose public chunks
+documents at <http://www.libpng.org/pub/png/documents/>.
+
+Other information
+about PNG, and the latest version of libpng, can be found at the PNG home
+page, <http://www.libpng.org/pub/png/>.
+
+Most users will not have to modify the library significantly; advanced
+users may want to modify it more. All attempts were made to make it as
+complete as possible, while keeping the code easy to understand.
+Currently, this library only supports C. Support for other languages
+is being considered.
+
+Libpng has been designed to handle multiple sessions at one time,
+to be easily modifiable, to be portable to the vast majority of
+machines (ANSI, K&R, 16-, 32-, and 64-bit) available, and to be easy
+to use. The ultimate goal of libpng is to promote the acceptance of
+the PNG file format in whatever way possible. While there is still
+work to be done (see the TODO file), libpng should cover the
+majority of the needs of its users.
+
+Libpng uses zlib for its compression and decompression of PNG files.
+Further information about zlib, and the latest version of zlib, can
+be found at the zlib home page, <http://www.info-zip.org/pub/infozip/zlib/>.
+The zlib compression utility is a general purpose utility that is
+useful for more than PNG files, and can be used without libpng.
+See the documentation delivered with zlib for more details.
+You can usually find the source files for the zlib utility wherever you
+find the libpng source files.
+
+Libpng is thread safe, provided the threads are using different
+instances of the structures. Each thread should have its own
+png_struct and png_info instances, and thus its own image.
+Libpng does not protect itself against two threads using the
+same instance of a structure.
+
+II. Structures
+
+There are two main structures that are important to libpng, png_struct
+and png_info. Both are internal structures that are no longer exposed
+in the libpng interface (as of libpng 1.5.0).
+
+The png_info structure is designed to provide information about the
+PNG file. At one time, the fields of png_info were intended to be
+directly accessible to the user. However, this tended to cause problems
+with applications using dynamically loaded libraries, and as a result
+a set of interface functions for png_info (the png_get_*() and png_set_*()
+functions) was developed, and direct access to the png_info fields was
+deprecated..
+
+The png_struct structure is the object used by the library to decode a
+single image. As of 1.5.0 this structure is also not exposed.
+
+Almost all libpng APIs require a pointer to a png_struct as the first argument.
+Many (in particular the png_set and png_get APIs) also require a pointer
+to png_info as the second argument. Some application visible macros
+defined in png.h designed for basic data access (reading and writing
+integers in the PNG format) don't take a png_info pointer, but it's almost
+always safe to assume that a (png_struct*) has to be passed to call an API
+function.
+
+You can have more than one png_info structure associated with an image,
+as illustrated in pngtest.c, one for information valid prior to the
+IDAT chunks and another (called "end_info" below) for things after them.
+
+The png.h header file is an invaluable reference for programming with libpng.
+And while I'm on the topic, make sure you include the libpng header file:
+
+#include <png.h>
+
+and also (as of libpng-1.5.0) the zlib header file, if you need it:
+
+#include <zlib.h>
+
+Types
+
+The png.h header file defines a number of integral types used by the
+APIs. Most of these are fairly obvious; for example types corresponding
+to integers of particular sizes and types for passing color values.
+
+One exception is how non-integral numbers are handled. For application
+convenience most APIs that take such numbers have C (double) arguments;
+however, internally PNG, and libpng, use 32 bit signed integers and encode
+the value by multiplying by 100,000. As of libpng 1.5.0 a convenience
+macro PNG_FP_1 is defined in png.h along with a type (png_fixed_point)
+which is simply (png_int_32).
+
+All APIs that take (double) arguments also have a matching API that
+takes the corresponding fixed point integer arguments. The fixed point
+API has the same name as the floating point one with "_fixed" appended.
+The actual range of values permitted in the APIs is frequently less than
+the full range of (png_fixed_point) (-21474 to +21474). When APIs require
+a non-negative argument the type is recorded as png_uint_32 above. Consult
+the header file and the text below for more information.
+
+Special care must be take with sCAL chunk handling because the chunk itself
+uses non-integral values encoded as strings containing decimal floating point
+numbers. See the comments in the header file.
+
+Configuration
+
+The main header file function declarations are frequently protected by C
+preprocessing directives of the form:
+
+ #ifdef PNG_feature_SUPPORTED
+ declare-function
+ #endif
+ ...
+ #ifdef PNG_feature_SUPPORTED
+ use-function
+ #endif
+
+The library can be built without support for these APIs, although a
+standard build will have all implemented APIs. Application programs
+should check the feature macros before using an API for maximum
+portability. From libpng 1.5.0 the feature macros set during the build
+of libpng are recorded in the header file "pnglibconf.h" and this file
+is always included by png.h.
+
+If you don't need to change the library configuration from the default, skip to
+the next section ("Reading").
+
+Notice that some of the makefiles in the 'scripts' directory and (in 1.5.0) all
+of the build project files in the 'projects' directory simply copy
+scripts/pnglibconf.h.prebuilt to pnglibconf.h. This means that these build
+systems do not permit easy auto-configuration of the library - they only
+support the default configuration.
+
+The easiest way to make minor changes to the libpng configuration when
+auto-configuration is supported is to add definitions to the command line
+using (typically) CPPFLAGS. For example:
+
+CPPFLAGS=-DPNG_NO_FLOATING_ARITHMETIC
+
+will change the internal libpng math implementation for gamma correction and
+other arithmetic calculations to fixed point, avoiding the need for fast
+floating point support. The result can be seen in the generated pnglibconf.h -
+make sure it contains the changed feature macro setting.
+
+If you need to make more extensive configuration changes - more than one or two
+feature macro settings - you can either add -DPNG_USER_CONFIG to the build
+command line and put a list of feature macro settings in pngusr.h or you can set
+DFA_XTRA (a makefile variable) to a file containing the same information in the
+form of 'option' settings.
+
+A. Changing pnglibconf.h
+
+A variety of methods exist to build libpng. Not all of these support
+reconfiguration of pnglibconf.h. To reconfigure pnglibconf.h it must either be
+rebuilt from scripts/pnglibconf.dfa using awk or it must be edited by hand.
+
+Hand editing is achieved by copying scripts/pnglibconf.h.prebuilt to
+pnglibconf.h and changing the lines defining the supported features, paying
+very close attention to the 'option' information in scripts/pnglibconf.dfa
+that describes those features and their requirements. This is easy to get
+wrong.
+
+B. Configuration using DFA_XTRA
+
+Rebuilding from pnglibconf.dfa is easy if a functioning 'awk', or a later
+variant such as 'nawk' or 'gawk', is available. The configure build will
+automatically find an appropriate awk and build pnglibconf.h.
+The scripts/pnglibconf.mak file contains a set of make rules for doing the
+same thing if configure is not used, and many of the makefiles in the scripts
+directory use this approach.
+
+When rebuilding simply write a new file containing changed options and set
+DFA_XTRA to the name of this file. This causes the build to append the new file
+to the end of scripts/pnglibconf.dfa. The pngusr.dfa file should contain lines
+of the following forms:
+
+everything = off
+
+This turns all optional features off. Include it at the start of pngusr.dfa to
+make it easier to build a minimal configuration. You will need to turn at least
+some features on afterward to enable either reading or writing code, or both.
+
+option feature on
+option feature off
+
+Enable or disable a single feature. This will automatically enable other
+features required by a feature that is turned on or disable other features that
+require a feature which is turned off. Conflicting settings will cause an error
+message to be emitted by awk.
+
+setting feature default value
+
+Changes the default value of setting 'feature' to 'value'. There are a small
+number of settings listed at the top of pnglibconf.h, they are documented in the
+source code. Most of these values have performance implications for the library
+but most of them have no visible effect on the API. Some can also be overridden
+from the API.
+
+This method of building a customized pnglibconf.h is illustrated in
+contrib/pngminim/*. See the "$(PNGCONF):" target in the makefile and
+pngusr.dfa in these directories.
+
+C. Configuration using PNG_USER_CONFIG
+
+If -DPNG_USER_CONFIG is added to the CPPFLAGS when pnglibconf.h is built,
+the file pngusr.h will automatically be included before the options in
+scripts/pnglibconf.dfa are processed. Your pngusr.h file should contain only
+macro definitions turning features on or off or setting settings.
+
+Apart from the global setting "everything = off" all the options listed above
+can be set using macros in pngusr.h:
+
+#define PNG_feature_SUPPORTED
+
+is equivalent to:
+
+option feature on
+
+#define PNG_NO_feature
+
+is equivalent to:
+
+option feature off
+
+#define PNG_feature value
+
+is equivalent to:
+
+setting feature default value
+
+Notice that in both cases, pngusr.dfa and pngusr.h, the contents of the
+pngusr file you supply override the contents of scripts/pnglibconf.dfa
+
+If confusing or incomprehensible behavior results it is possible to
+examine the intermediate file pnglibconf.dfn to find the full set of
+dependency information for each setting and option. Simply locate the
+feature in the file and read the C comments that precede it.
+
+This method is also illustrated in the contrib/pngminim/* makefiles and
+pngusr.h.
+
+III. Reading
+
+We'll now walk you through the possible functions to call when reading
+in a PNG file sequentially, briefly explaining the syntax and purpose
+of each one. See example.c and png.h for more detail. While
+progressive reading is covered in the next section, you will still
+need some of the functions discussed in this section to read a PNG
+file.
+
+Setup
+
+You will want to do the I/O initialization(*) before you get into libpng,
+so if it doesn't work, you don't have much to undo. Of course, you
+will also want to insure that you are, in fact, dealing with a PNG
+file. Libpng provides a simple check to see if a file is a PNG file.
+To use it, pass in the first 1 to 8 bytes of the file to the function
+png_sig_cmp(), and it will return 0 (false) if the bytes match the
+corresponding bytes of the PNG signature, or nonzero (true) otherwise.
+Of course, the more bytes you pass in, the greater the accuracy of the
+prediction.
+
+If you are intending to keep the file pointer open for use in libpng,
+you must ensure you don't read more than 8 bytes from the beginning
+of the file, and you also have to make a call to png_set_sig_bytes()
+with the number of bytes you read from the beginning. Libpng will
+then only check the bytes (if any) that your program didn't read.
+
+(*): If you are not using the standard I/O functions, you will need
+to replace them with custom functions. See the discussion under
+Customizing libpng.
+
+ FILE *fp = fopen(file_name, "rb");
+ if (!fp)
+ {
+ return (ERROR);
+ }
+
+ if (fread(header, 1, number, fp) != number)
+ {
+ return (ERROR);
+ }
+
+ is_png = !png_sig_cmp(header, 0, number);
+ if (!is_png)
+ {
+ return (NOT_PNG);
+ }
+
+Next, png_struct and png_info need to be allocated and initialized. In
+order to ensure that the size of these structures is correct even with a
+dynamically linked libpng, there are functions to initialize and
+allocate the structures. We also pass the library version, optional
+pointers to error handling functions, and a pointer to a data struct for
+use by the error functions, if necessary (the pointer and functions can
+be NULL if the default error handlers are to be used). See the section
+on Changes to Libpng below regarding the old initialization functions.
+The structure allocation functions quietly return NULL if they fail to
+create the structure, so your application should check for that.
+
+ png_structp png_ptr = png_create_read_struct
+ (PNG_LIBPNG_VER_STRING, (png_voidp)user_error_ptr,
+ user_error_fn, user_warning_fn);
+
+ if (!png_ptr)
+ return (ERROR);
+
+ png_infop info_ptr = png_create_info_struct(png_ptr);
+
+ if (!info_ptr)
+ {
+ png_destroy_read_struct(&png_ptr,
+ (png_infopp)NULL, (png_infopp)NULL);
+ return (ERROR);
+ }
+
+If you want to use your own memory allocation routines,
+use a libpng that was built with PNG_USER_MEM_SUPPORTED defined, and use
+png_create_read_struct_2() instead of png_create_read_struct():
+
+ png_structp png_ptr = png_create_read_struct_2
+ (PNG_LIBPNG_VER_STRING, (png_voidp)user_error_ptr,
+ user_error_fn, user_warning_fn, (png_voidp)
+ user_mem_ptr, user_malloc_fn, user_free_fn);
+
+The error handling routines passed to png_create_read_struct()
+and the memory alloc/free routines passed to png_create_struct_2()
+are only necessary if you are not using the libpng supplied error
+handling and memory alloc/free functions.
+
+When libpng encounters an error, it expects to longjmp back
+to your routine. Therefore, you will need to call setjmp and pass
+your png_jmpbuf(png_ptr). If you read the file from different
+routines, you will need to update the longjmp buffer every time you enter
+a new routine that will call a png_*() function.
+
+See your documentation of setjmp/longjmp for your compiler for more
+information on setjmp/longjmp. See the discussion on libpng error
+handling in the Customizing Libpng section below for more information
+on the libpng error handling. If an error occurs, and libpng longjmp's
+back to your setjmp, you will want to call png_destroy_read_struct() to
+free any memory.
+
+ if (setjmp(png_jmpbuf(png_ptr)))
+ {
+ png_destroy_read_struct(&png_ptr, &info_ptr,
+ &end_info);
+ fclose(fp);
+ return (ERROR);
+ }
+
+Pass (png_infopp)NULL instead of &end_info if you didn't create
+an end_info structure.
+
+If you would rather avoid the complexity of setjmp/longjmp issues,
+you can compile libpng with PNG_NO_SETJMP, in which case
+errors will result in a call to PNG_ABORT() which defaults to abort().
+
+You can #define PNG_ABORT() to a function that does something
+more useful than abort(), as long as your function does not
+return.
+
+Now you need to set up the input code. The default for libpng is to
+use the C function fread(). If you use this, you will need to pass a
+valid FILE * in the function png_init_io(). Be sure that the file is
+opened in binary mode. If you wish to handle reading data in another
+way, you need not call the png_init_io() function, but you must then
+implement the libpng I/O methods discussed in the Customizing Libpng
+section below.
+
+ png_init_io(png_ptr, fp);
+
+If you had previously opened the file and read any of the signature from
+the beginning in order to see if this was a PNG file, you need to let
+libpng know that there are some bytes missing from the start of the file.
+
+ png_set_sig_bytes(png_ptr, number);
+
+You can change the zlib compression buffer size to be used while
+reading compressed data with
+
+ png_set_compression_buffer_size(png_ptr, buffer_size);
+
+where the default size is 8192 bytes. Note that the buffer size
+is changed immediately and the buffer is reallocated immediately,
+instead of setting a flag to be acted upon later.
+
+If you want CRC errors to be handled in a different manner than
+the default, use
+
+ png_set_crc_action(png_ptr, crit_action, ancil_action);
+
+The values for png_set_crc_action() say how libpng is to handle CRC errors in
+ancillary and critical chunks, and whether to use the data contained
+therein. Note that it is impossible to "discard" data in a critical
+chunk.
+
+Choices for (int) crit_action are
+ PNG_CRC_DEFAULT 0 error/quit
+ PNG_CRC_ERROR_QUIT 1 error/quit
+ PNG_CRC_WARN_USE 3 warn/use data
+ PNG_CRC_QUIET_USE 4 quiet/use data
+ PNG_CRC_NO_CHANGE 5 use the current value
+
+Choices for (int) ancil_action are
+ PNG_CRC_DEFAULT 0 error/quit
+ PNG_CRC_ERROR_QUIT 1 error/quit
+ PNG_CRC_WARN_DISCARD 2 warn/discard data
+ PNG_CRC_WARN_USE 3 warn/use data
+ PNG_CRC_QUIET_USE 4 quiet/use data
+ PNG_CRC_NO_CHANGE 5 use the current value
+
+Setting up callback code
+
+You can set up a callback function to handle any unknown chunks in the
+input stream. You must supply the function
+
+ read_chunk_callback(png_structp png_ptr,
+ png_unknown_chunkp chunk);
+ {
+ /* The unknown chunk structure contains your
+ chunk data, along with similar data for any other
+ unknown chunks: */
+
+ png_byte name[5];
+ png_byte *data;
+ png_size_t size;
+
+ /* Note that libpng has already taken care of
+ the CRC handling */
+
+ /* put your code here. Search for your chunk in the
+ unknown chunk structure, process it, and return one
+ of the following: */
+
+ return (-n); /* chunk had an error */
+ return (0); /* did not recognize */
+ return (n); /* success */
+ }
+
+(You can give your function another name that you like instead of
+"read_chunk_callback")
+
+To inform libpng about your function, use
+
+ png_set_read_user_chunk_fn(png_ptr, user_chunk_ptr,
+ read_chunk_callback);
+
+This names not only the callback function, but also a user pointer that
+you can retrieve with
+
+ png_get_user_chunk_ptr(png_ptr);
+
+If you call the png_set_read_user_chunk_fn() function, then all unknown
+chunks which the callback does not handle will be saved when read. You can
+cause them to be discarded by returning '1' ("handled") instead of '0'. This
+behavior will change in libpng 1.7 and the default handling set by the
+png_set_keep_unknown_chunks() function, described below, will be used when the
+callback returns 0. If you want the existing behavior you should set the global
+default to PNG_HANDLE_CHUNK_IF_SAFE now; this is compatible with all current
+versions of libpng and with 1.7. Libpng 1.6 issues a warning if you keep the
+default, or PNG_HANDLE_CHUNK_NEVER, and the callback returns 0.
+
+At this point, you can set up a callback function that will be
+called after each row has been read, which you can use to control
+a progress meter or the like. It's demonstrated in pngtest.c.
+You must supply a function
+
+ void read_row_callback(png_structp png_ptr,
+ png_uint_32 row, int pass);
+ {
+ /* put your code here */
+ }
+
+(You can give it another name that you like instead of "read_row_callback")
+
+To inform libpng about your function, use
+
+ png_set_read_status_fn(png_ptr, read_row_callback);
+
+When this function is called the row has already been completely processed and
+the 'row' and 'pass' refer to the next row to be handled. For the
+non-interlaced case the row that was just handled is simply one less than the
+passed in row number, and pass will always be 0. For the interlaced case the
+same applies unless the row value is 0, in which case the row just handled was
+the last one from one of the preceding passes. Because interlacing may skip a
+pass you cannot be sure that the preceding pass is just 'pass-1', if you really
+need to know what the last pass is record (row,pass) from the callback and use
+the last recorded value each time.
+
+As with the user transform you can find the output row using the
+PNG_ROW_FROM_PASS_ROW macro.
+
+Unknown-chunk handling
+
+Now you get to set the way the library processes unknown chunks in the
+input PNG stream. Both known and unknown chunks will be read. Normal
+behavior is that known chunks will be parsed into information in
+various info_ptr members while unknown chunks will be discarded. This
+behavior can be wasteful if your application will never use some known
+chunk types. To change this, you can call:
+
+ png_set_keep_unknown_chunks(png_ptr, keep,
+ chunk_list, num_chunks);
+
+ keep - 0: default unknown chunk handling
+ 1: ignore; do not keep
+ 2: keep only if safe-to-copy
+ 3: keep even if unsafe-to-copy
+
+ You can use these definitions:
+ PNG_HANDLE_CHUNK_AS_DEFAULT 0
+ PNG_HANDLE_CHUNK_NEVER 1
+ PNG_HANDLE_CHUNK_IF_SAFE 2
+ PNG_HANDLE_CHUNK_ALWAYS 3
+
+ chunk_list - list of chunks affected (a byte string,
+ five bytes per chunk, NULL or '\0' if
+ num_chunks is positive; ignored if
+ numchunks <= 0).
+
+ num_chunks - number of chunks affected; if 0, all
+ unknown chunks are affected. If positive,
+ only the chunks in the list are affected,
+ and if negative all unknown chunks and
+ all known chunks except for the IHDR,
+ PLTE, tRNS, IDAT, and IEND chunks are
+ affected.
+
+Unknown chunks declared in this way will be saved as raw data onto a
+list of png_unknown_chunk structures. If a chunk that is normally
+known to libpng is named in the list, it will be handled as unknown,
+according to the "keep" directive. If a chunk is named in successive
+instances of png_set_keep_unknown_chunks(), the final instance will
+take precedence. The IHDR and IEND chunks should not be named in
+chunk_list; if they are, libpng will process them normally anyway.
+If you know that your application will never make use of some particular
+chunks, use PNG_HANDLE_CHUNK_NEVER (or 1) as demonstrated below.
+
+Here is an example of the usage of png_set_keep_unknown_chunks(),
+where the private "vpAg" chunk will later be processed by a user chunk
+callback function:
+
+ png_byte vpAg[5]={118, 112, 65, 103, (png_byte) '\0'};
+
+ #if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)
+ png_byte unused_chunks[]=
+ {
+ 104, 73, 83, 84, (png_byte) '\0', /* hIST */
+ 105, 84, 88, 116, (png_byte) '\0', /* iTXt */
+ 112, 67, 65, 76, (png_byte) '\0', /* pCAL */
+ 115, 67, 65, 76, (png_byte) '\0', /* sCAL */
+ 115, 80, 76, 84, (png_byte) '\0', /* sPLT */
+ 116, 73, 77, 69, (png_byte) '\0', /* tIME */
+ };
+ #endif
+
+ ...
+
+ #if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)
+ /* ignore all unknown chunks
+ * (use global setting "2" for libpng16 and earlier):
+ */
+ png_set_keep_unknown_chunks(read_ptr, 2, NULL, 0);
+
+ /* except for vpAg: */
+ png_set_keep_unknown_chunks(read_ptr, 2, vpAg, 1);
+
+ /* also ignore unused known chunks: */
+ png_set_keep_unknown_chunks(read_ptr, 1, unused_chunks,
+ (int)(sizeof unused_chunks)/5);
+ #endif
+
+User limits
+
+The PNG specification allows the width and height of an image to be as
+large as 2^31-1 (0x7fffffff), or about 2.147 billion rows and columns.
+Larger images will be rejected immediately with a png_error() call. If
+you wish to change these limits, you can use
+
+ png_set_user_limits(png_ptr, width_max, height_max);
+
+to set your own limits (libpng may reject some very wide images
+anyway because of potential buffer overflow conditions).
+
+You should put this statement after you create the PNG structure and
+before calling png_read_info(), png_read_png(), or png_process_data().
+
+When writing a PNG datastream, put this statement before calling
+png_write_info() or png_write_png().
+
+If you need to retrieve the limits that are being applied, use
+
+ width_max = png_get_user_width_max(png_ptr);
+ height_max = png_get_user_height_max(png_ptr);
+
+The PNG specification sets no limit on the number of ancillary chunks
+allowed in a PNG datastream. You can impose a limit on the total number
+of sPLT, tEXt, iTXt, zTXt, and unknown chunks that will be stored, with
+
+ png_set_chunk_cache_max(png_ptr, user_chunk_cache_max);
+
+where 0x7fffffffL means unlimited. You can retrieve this limit with
+
+ chunk_cache_max = png_get_chunk_cache_max(png_ptr);
+
+You can also set a limit on the amount of memory that a compressed chunk
+other than IDAT can occupy, with
+
+ png_set_chunk_malloc_max(png_ptr, user_chunk_malloc_max);
+
+and you can retrieve the limit with
+
+ chunk_malloc_max = png_get_chunk_malloc_max(png_ptr);
+
+Any chunks that would cause either of these limits to be exceeded will
+be ignored.
+
+Information about your system
+
+If you intend to display the PNG or to incorporate it in other image data you
+need to tell libpng information about your display or drawing surface so that
+libpng can convert the values in the image to match the display.
+
+From libpng-1.5.4 this information can be set before reading the PNG file
+header. In earlier versions png_set_gamma() existed but behaved incorrectly if
+called before the PNG file header had been read and png_set_alpha_mode() did not
+exist.
+
+If you need to support versions prior to libpng-1.5.4 test the version number
+as illustrated below using "PNG_LIBPNG_VER >= 10504" and follow the procedures
+described in the appropriate manual page.
+
+You give libpng the encoding expected by your system expressed as a 'gamma'
+value. You can also specify a default encoding for the PNG file in
+case the required information is missing from the file. By default libpng
+assumes that the PNG data matches your system, to keep this default call:
+
+ png_set_gamma(png_ptr, screen_gamma, output_gamma);
+
+or you can use the fixed point equivalent:
+
+ png_set_gamma_fixed(png_ptr, PNG_FP_1*screen_gamma,
+ PNG_FP_1*output_gamma);
+
+If you don't know the gamma for your system it is probably 2.2 - a good
+approximation to the IEC standard for display systems (sRGB). If images are
+too contrasty or washed out you got the value wrong - check your system
+documentation!
+
+Many systems permit the system gamma to be changed via a lookup table in the
+display driver, a few systems, including older Macs, change the response by
+default. As of 1.5.4 three special values are available to handle common
+situations:
+
+ PNG_DEFAULT_sRGB: Indicates that the system conforms to the
+ IEC 61966-2-1 standard. This matches almost
+ all systems.
+ PNG_GAMMA_MAC_18: Indicates that the system is an older
+ (pre Mac OS 10.6) Apple Macintosh system with
+ the default settings.
+ PNG_GAMMA_LINEAR: Just the fixed point value for 1.0 - indicates
+ that the system expects data with no gamma
+ encoding.
+
+You would use the linear (unencoded) value if you need to process the pixel
+values further because this avoids the need to decode and re-encode each
+component value whenever arithmetic is performed. A lot of graphics software
+uses linear values for this reason, often with higher precision component values
+to preserve overall accuracy.
+
+
+The output_gamma value expresses how to decode the output values, not how
+they are encoded. The values used correspond to the normal numbers used to
+describe the overall gamma of a computer display system; for example 2.2 for
+an sRGB conformant system. The values are scaled by 100000 in the _fixed
+version of the API (so 220000 for sRGB.)
+
+The inverse of the value is always used to provide a default for the PNG file
+encoding if it has no gAMA chunk and if png_set_gamma() has not been called
+to override the PNG gamma information.
+
+When the ALPHA_OPTIMIZED mode is selected the output gamma is used to encode
+opaque pixels however pixels with lower alpha values are not encoded,
+regardless of the output gamma setting.
+
+When the standard Porter Duff handling is requested with mode 1 the output
+encoding is set to be linear and the output_gamma value is only relevant
+as a default for input data that has no gamma information. The linear output
+encoding will be overridden if png_set_gamma() is called - the results may be
+highly unexpected!
+
+The following numbers are derived from the sRGB standard and the research
+behind it. sRGB is defined to be approximated by a PNG gAMA chunk value of
+0.45455 (1/2.2) for PNG. The value implicitly includes any viewing
+correction required to take account of any differences in the color
+environment of the original scene and the intended display environment; the
+value expresses how to *decode* the image for display, not how the original
+data was *encoded*.
+
+sRGB provides a peg for the PNG standard by defining a viewing environment.
+sRGB itself, and earlier TV standards, actually use a more complex transform
+(a linear portion then a gamma 2.4 power law) than PNG can express. (PNG is
+limited to simple power laws.) By saying that an image for direct display on
+an sRGB conformant system should be stored with a gAMA chunk value of 45455
+(11.3.3.2 and 11.3.3.5 of the ISO PNG specification) the PNG specification
+makes it possible to derive values for other display systems and
+environments.
+
+The Mac value is deduced from the sRGB based on an assumption that the actual
+extra viewing correction used in early Mac display systems was implemented as
+a power 1.45 lookup table.
+
+Any system where a programmable lookup table is used or where the behavior of
+the final display device characteristics can be changed requires system
+specific code to obtain the current characteristic. However this can be
+difficult and most PNG gamma correction only requires an approximate value.
+
+By default, if png_set_alpha_mode() is not called, libpng assumes that all
+values are unencoded, linear, values and that the output device also has a
+linear characteristic. This is only very rarely correct - it is invariably
+better to call png_set_alpha_mode() with PNG_DEFAULT_sRGB than rely on the
+default if you don't know what the right answer is!
+
+The special value PNG_GAMMA_MAC_18 indicates an older Mac system (pre Mac OS
+10.6) which used a correction table to implement a somewhat lower gamma on an
+otherwise sRGB system.
+
+Both these values are reserved (not simple gamma values) in order to allow
+more precise correction internally in the future.
+
+NOTE: the values can be passed to either the fixed or floating
+point APIs, but the floating point API will also accept floating point
+values.
+
+The second thing you may need to tell libpng about is how your system handles
+alpha channel information. Some, but not all, PNG files contain an alpha
+channel. To display these files correctly you need to compose the data onto a
+suitable background, as described in the PNG specification.
+
+Libpng only supports composing onto a single color (using png_set_background;
+see below). Otherwise you must do the composition yourself and, in this case,
+you may need to call png_set_alpha_mode:
+
+ #if PNG_LIBPNG_VER >= 10504
+ png_set_alpha_mode(png_ptr, mode, screen_gamma);
+ #else
+ png_set_gamma(png_ptr, screen_gamma, 1.0/screen_gamma);
+ #endif
+
+The screen_gamma value is the same as the argument to png_set_gamma; however,
+how it affects the output depends on the mode. png_set_alpha_mode() sets the
+file gamma default to 1/screen_gamma, so normally you don't need to call
+png_set_gamma. If you need different defaults call png_set_gamma() before
+png_set_alpha_mode() - if you call it after it will override the settings made
+by png_set_alpha_mode().
+
+The mode is as follows:
+
+ PNG_ALPHA_PNG: The data is encoded according to the PNG
+specification. Red, green and blue, or gray, components are
+gamma encoded color values and are not premultiplied by the
+alpha value. The alpha value is a linear measure of the
+contribution of the pixel to the corresponding final output pixel.
+
+You should normally use this format if you intend to perform
+color correction on the color values; most, maybe all, color
+correction software has no handling for the alpha channel and,
+anyway, the math to handle pre-multiplied component values is
+unnecessarily complex.
+
+Before you do any arithmetic on the component values you need
+to remove the gamma encoding and multiply out the alpha
+channel. See the PNG specification for more detail. It is
+important to note that when an image with an alpha channel is
+scaled, linear encoded, pre-multiplied component values must
+be used!
+
+The remaining modes assume you don't need to do any further color correction or
+that if you do, your color correction software knows all about alpha (it
+probably doesn't!). They 'associate' the alpha with the color information by
+storing color channel values that have been scaled by the alpha. The
+advantage is that the color channels can be resampled (the image can be
+scaled) in this form. The disadvantage is that normal practice is to store
+linear, not (gamma) encoded, values and this requires 16-bit channels for
+still images rather than the 8-bit channels that are just about sufficient if
+gamma encoding is used. In addition all non-transparent pixel values,
+including completely opaque ones, must be gamma encoded to produce the final
+image. These are the 'STANDARD', 'ASSOCIATED' or 'PREMULTIPLIED' modes
+described below (the latter being the two common names for associated alpha
+color channels). Note that PNG files always contain non-associated color
+channels; png_set_alpha_mode() with one of the modes causes the decoder to
+convert the pixels to an associated form before returning them to your
+application.
+
+Since it is not necessary to perform arithmetic on opaque color values so
+long as they are not to be resampled and are in the final color space it is
+possible to optimize the handling of alpha by storing the opaque pixels in
+the PNG format (adjusted for the output color space) while storing partially
+opaque pixels in the standard, linear, format. The accuracy required for
+standard alpha composition is relatively low, because the pixels are
+isolated, therefore typically the accuracy loss in storing 8-bit linear
+values is acceptable. (This is not true if the alpha channel is used to
+simulate transparency over large areas - use 16 bits or the PNG mode in
+this case!) This is the 'OPTIMIZED' mode. For this mode a pixel is
+treated as opaque only if the alpha value is equal to the maximum value.
+
+ PNG_ALPHA_STANDARD: The data libpng produces is encoded in the
+standard way assumed by most correctly written graphics software.
+The gamma encoding will be removed by libpng and the
+linear component values will be pre-multiplied by the
+alpha channel.
+
+With this format the final image must be re-encoded to
+match the display gamma before the image is displayed.
+If your system doesn't do that, yet still seems to
+perform arithmetic on the pixels without decoding them,
+it is broken - check out the modes below.
+
+With PNG_ALPHA_STANDARD libpng always produces linear
+component values, whatever screen_gamma you supply. The
+screen_gamma value is, however, used as a default for
+the file gamma if the PNG file has no gamma information.
+
+If you call png_set_gamma() after png_set_alpha_mode() you
+will override the linear encoding. Instead the
+pre-multiplied pixel values will be gamma encoded but
+the alpha channel will still be linear. This may
+actually match the requirements of some broken software,
+but it is unlikely.
+
+While linear 8-bit data is often used it has
+insufficient precision for any image with a reasonable
+dynamic range. To avoid problems, and if your software
+supports it, use png_set_expand_16() to force all
+components to 16 bits.
+
+ PNG_ALPHA_OPTIMIZED: This mode is the same as PNG_ALPHA_STANDARD
+except that completely opaque pixels are gamma encoded according to
+the screen_gamma value. Pixels with alpha less than 1.0
+will still have linear components.
+
+Use this format if you have control over your
+compositing software and so don't do other arithmetic
+(such as scaling) on the data you get from libpng. Your
+compositing software can simply copy opaque pixels to
+the output but still has linear values for the
+non-opaque pixels.
+
+In normal compositing, where the alpha channel encodes
+partial pixel coverage (as opposed to broad area
+translucency), the inaccuracies of the 8-bit
+representation of non-opaque pixels are irrelevant.
+
+You can also try this format if your software is broken;
+it might look better.
+
+ PNG_ALPHA_BROKEN: This is PNG_ALPHA_STANDARD; however, all component
+values, including the alpha channel are gamma encoded. This is
+broken because, in practice, no implementation that uses this choice
+correctly undoes the encoding before handling alpha composition. Use this
+choice only if other serious errors in the software or hardware you use
+mandate it. In most cases of broken software or hardware the bug in the
+final display manifests as a subtle halo around composited parts of the
+image. You may not even perceive this as a halo; the composited part of
+the image may simply appear separate from the background, as though it had
+been cut out of paper and pasted on afterward.
+
+If you don't have to deal with bugs in software or hardware, or if you can fix
+them, there are three recommended ways of using png_set_alpha_mode():
+
+ png_set_alpha_mode(png_ptr, PNG_ALPHA_PNG,
+ screen_gamma);
+
+You can do color correction on the result (libpng does not currently
+support color correction internally). When you handle the alpha channel
+you need to undo the gamma encoding and multiply out the alpha.
+
+ png_set_alpha_mode(png_ptr, PNG_ALPHA_STANDARD,
+ screen_gamma);
+ png_set_expand_16(png_ptr);
+
+If you are using the high level interface, don't call png_set_expand_16();
+instead pass PNG_TRANSFORM_EXPAND_16 to the interface.
+
+With this mode you can't do color correction, but you can do arithmetic,
+including composition and scaling, on the data without further processing.
+
+ png_set_alpha_mode(png_ptr, PNG_ALPHA_OPTIMIZED,
+ screen_gamma);
+
+You can avoid the expansion to 16-bit components with this mode, but you
+lose the ability to scale the image or perform other linear arithmetic.
+All you can do is compose the result onto a matching output. Since this
+mode is libpng-specific you also need to write your own composition
+software.
+
+The following are examples of calls to png_set_alpha_mode to achieve the
+required overall gamma correction and, where necessary, alpha
+premultiplication.
+
+ png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_DEFAULT_sRGB);
+
+This is the default libpng handling of the alpha channel - it is not
+pre-multiplied into the color components. In addition the call states
+that the output is for a sRGB system and causes all PNG files without gAMA
+chunks to be assumed to be encoded using sRGB.
+
+ png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_GAMMA_MAC);
+
+In this case the output is assumed to be something like an sRGB conformant
+display preceeded by a power-law lookup table of power 1.45. This is how
+early Mac systems behaved.
+
+ png_set_alpha_mode(pp, PNG_ALPHA_STANDARD, PNG_GAMMA_LINEAR);
+
+This is the classic Jim Blinn approach and will work in academic
+environments where everything is done by the book. It has the shortcoming
+of assuming that input PNG data with no gamma information is linear - this
+is unlikely to be correct unless the PNG files where generated locally.
+Most of the time the output precision will be so low as to show
+significant banding in dark areas of the image.
+
+ png_set_expand_16(pp);
+ png_set_alpha_mode(pp, PNG_ALPHA_STANDARD, PNG_DEFAULT_sRGB);
+
+This is a somewhat more realistic Jim Blinn inspired approach. PNG files
+are assumed to have the sRGB encoding if not marked with a gamma value and
+the output is always 16 bits per component. This permits accurate scaling
+and processing of the data. If you know that your input PNG files were
+generated locally you might need to replace PNG_DEFAULT_sRGB with the
+correct value for your system.
+
+ png_set_alpha_mode(pp, PNG_ALPHA_OPTIMIZED, PNG_DEFAULT_sRGB);
+
+If you just need to composite the PNG image onto an existing background
+and if you control the code that does this you can use the optimization
+setting. In this case you just copy completely opaque pixels to the
+output. For pixels that are not completely transparent (you just skip
+those) you do the composition math using png_composite or png_composite_16
+below then encode the resultant 8-bit or 16-bit values to match the output
+encoding.
+
+ Other cases
+
+If neither the PNG nor the standard linear encoding work for you because
+of the software or hardware you use then you have a big problem. The PNG
+case will probably result in halos around the image. The linear encoding
+will probably result in a washed out, too bright, image (it's actually too
+contrasty.) Try the ALPHA_OPTIMIZED mode above - this will probably
+substantially reduce the halos. Alternatively try:
+
+ png_set_alpha_mode(pp, PNG_ALPHA_BROKEN, PNG_DEFAULT_sRGB);
+
+This option will also reduce the halos, but there will be slight dark
+halos round the opaque parts of the image where the background is light.
+In the OPTIMIZED mode the halos will be light halos where the background
+is dark. Take your pick - the halos are unavoidable unless you can get
+your hardware/software fixed! (The OPTIMIZED approach is slightly
+faster.)
+
+When the default gamma of PNG files doesn't match the output gamma.
+If you have PNG files with no gamma information png_set_alpha_mode allows
+you to provide a default gamma, but it also sets the ouput gamma to the
+matching value. If you know your PNG files have a gamma that doesn't
+match the output you can take advantage of the fact that
+png_set_alpha_mode always sets the output gamma but only sets the PNG
+default if it is not already set:
+
+ png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_DEFAULT_sRGB);
+ png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_GAMMA_MAC);
+
+The first call sets both the default and the output gamma values, the
+second call overrides the output gamma without changing the default. This
+is easier than achieving the same effect with png_set_gamma. You must use
+PNG_ALPHA_PNG for the first call - internal checking in png_set_alpha will
+fire if more than one call to png_set_alpha_mode and png_set_background is
+made in the same read operation, however multiple calls with PNG_ALPHA_PNG
+are ignored.
+
+If you don't need, or can't handle, the alpha channel you can call
+png_set_background() to remove it by compositing against a fixed color. Don't
+call png_set_strip_alpha() to do this - it will leave spurious pixel values in
+transparent parts of this image.
+
+ png_set_background(png_ptr, &background_color,
+ PNG_BACKGROUND_GAMMA_SCREEN, 0, 1);
+
+The background_color is an RGB or grayscale value according to the data format
+libpng will produce for you. Because you don't yet know the format of the PNG
+file, if you call png_set_background at this point you must arrange for the
+format produced by libpng to always have 8-bit or 16-bit components and then
+store the color as an 8-bit or 16-bit color as appropriate. The color contains
+separate gray and RGB component values, so you can let libpng produce gray or
+RGB output according to the input format, but low bit depth grayscale images
+must always be converted to at least 8-bit format. (Even though low bit depth
+grayscale images can't have an alpha channel they can have a transparent
+color!)
+
+You set the transforms you need later, either as flags to the high level
+interface or libpng API calls for the low level interface. For reference the
+settings and API calls required are:
+
+8-bit values:
+ PNG_TRANSFORM_SCALE_16 | PNG_EXPAND
+ png_set_expand(png_ptr); png_set_scale_16(png_ptr);
+
+ If you must get exactly the same inaccurate results
+ produced by default in versions prior to libpng-1.5.4,
+ use PNG_TRANSFORM_STRIP_16 and png_set_strip_16(png_ptr)
+ instead.
+
+16-bit values:
+ PNG_TRANSFORM_EXPAND_16
+ png_set_expand_16(png_ptr);
+
+In either case palette image data will be expanded to RGB. If you just want
+color data you can add PNG_TRANSFORM_GRAY_TO_RGB or png_set_gray_to_rgb(png_ptr)
+to the list.
+
+Calling png_set_background before the PNG file header is read will not work
+prior to libpng-1.5.4. Because the failure may result in unexpected warnings or
+errors it is therefore much safer to call png_set_background after the head has
+been read. Unfortunately this means that prior to libpng-1.5.4 it cannot be
+used with the high level interface.
+
+The high-level read interface
+
+At this point there are two ways to proceed; through the high-level
+read interface, or through a sequence of low-level read operations.
+You can use the high-level interface if (a) you are willing to read
+the entire image into memory, and (b) the input transformations
+you want to do are limited to the following set:
+
+ PNG_TRANSFORM_IDENTITY No transformation
+ PNG_TRANSFORM_SCALE_16 Strip 16-bit samples to
+ 8-bit accurately
+ PNG_TRANSFORM_STRIP_16 Chop 16-bit samples to
+ 8-bit less accurately
+ PNG_TRANSFORM_STRIP_ALPHA Discard the alpha channel
+ PNG_TRANSFORM_PACKING Expand 1, 2 and 4-bit
+ samples to bytes
+ PNG_TRANSFORM_PACKSWAP Change order of packed
+ pixels to LSB first
+ PNG_TRANSFORM_EXPAND Perform set_expand()
+ PNG_TRANSFORM_INVERT_MONO Invert monochrome images
+ PNG_TRANSFORM_SHIFT Normalize pixels to the
+ sBIT depth
+ PNG_TRANSFORM_BGR Flip RGB to BGR, RGBA
+ to BGRA
+ PNG_TRANSFORM_SWAP_ALPHA Flip RGBA to ARGB or GA
+ to AG
+ PNG_TRANSFORM_INVERT_ALPHA Change alpha from opacity
+ to transparency
+ PNG_TRANSFORM_SWAP_ENDIAN Byte-swap 16-bit samples
+ PNG_TRANSFORM_GRAY_TO_RGB Expand grayscale samples
+ to RGB (or GA to RGBA)
+ PNG_TRANSFORM_EXPAND_16 Expand samples to 16 bits
+
+(This excludes setting a background color, doing gamma transformation,
+quantizing, and setting filler.) If this is the case, simply do this:
+
+ png_read_png(png_ptr, info_ptr, png_transforms, NULL)
+
+where png_transforms is an integer containing the bitwise OR of some
+set of transformation flags. This call is equivalent to png_read_info(),
+followed the set of transformations indicated by the transform mask,
+then png_read_image(), and finally png_read_end().
+
+(The final parameter of this call is not yet used. Someday it might point
+to transformation parameters required by some future input transform.)
+
+You must use png_transforms and not call any png_set_transform() functions
+when you use png_read_png().
+
+After you have called png_read_png(), you can retrieve the image data
+with
+
+ row_pointers = png_get_rows(png_ptr, info_ptr);
+
+where row_pointers is an array of pointers to the pixel data for each row:
+
+ png_bytep row_pointers[height];
+
+If you know your image size and pixel size ahead of time, you can allocate
+row_pointers prior to calling png_read_png() with
+
+ if (height > PNG_UINT_32_MAX/(sizeof (png_byte)))
+ png_error (png_ptr,
+ "Image is too tall to process in memory");
+
+ if (width > PNG_UINT_32_MAX/pixel_size)
+ png_error (png_ptr,
+ "Image is too wide to process in memory");
+
+ row_pointers = png_malloc(png_ptr,
+ height*(sizeof (png_bytep)));
+
+ for (int i=0; i<height, i++)
+ row_pointers[i]=NULL; /* security precaution */
+
+ for (int i=0; i<height, i++)
+ row_pointers[i]=png_malloc(png_ptr,
+ width*pixel_size);
+
+ png_set_rows(png_ptr, info_ptr, &row_pointers);
+
+Alternatively you could allocate your image in one big block and define
+row_pointers[i] to point into the proper places in your block.
+
+If you use png_set_rows(), the application is responsible for freeing
+row_pointers (and row_pointers[i], if they were separately allocated).
+
+If you don't allocate row_pointers ahead of time, png_read_png() will
+do it, and it'll be free'ed by libpng when you call png_destroy_*().
+
+The low-level read interface
+
+If you are going the low-level route, you are now ready to read all
+the file information up to the actual image data. You do this with a
+call to png_read_info().
+
+ png_read_info(png_ptr, info_ptr);
+
+This will process all chunks up to but not including the image data.
+
+This also copies some of the data from the PNG file into the decode structure
+for use in later transformations. Important information copied in is:
+
+1) The PNG file gamma from the gAMA chunk. This overwrites the default value
+provided by an earlier call to png_set_gamma or png_set_alpha_mode.
+
+2) Prior to libpng-1.5.4 the background color from a bKGd chunk. This
+damages the information provided by an earlier call to png_set_background
+resulting in unexpected behavior. Libpng-1.5.4 no longer does this.
+
+3) The number of significant bits in each component value. Libpng uses this to
+optimize gamma handling by reducing the internal lookup table sizes.
+
+4) The transparent color information from a tRNS chunk. This can be modified by
+a later call to png_set_tRNS.
+
+Querying the info structure
+
+Functions are used to get the information from the info_ptr once it
+has been read. Note that these fields may not be completely filled
+in until png_read_end() has read the chunk data following the image.
+
+ png_get_IHDR(png_ptr, info_ptr, &width, &height,
+ &bit_depth, &color_type, &interlace_type,
+ &compression_type, &filter_method);
+
+ width - holds the width of the image
+ in pixels (up to 2^31).
+
+ height - holds the height of the image
+ in pixels (up to 2^31).
+
+ bit_depth - holds the bit depth of one of the
+ image channels. (valid values are
+ 1, 2, 4, 8, 16 and depend also on
+ the color_type. See also
+ significant bits (sBIT) below).
+
+ color_type - describes which color/alpha channels
+ are present.
+ PNG_COLOR_TYPE_GRAY
+ (bit depths 1, 2, 4, 8, 16)
+ PNG_COLOR_TYPE_GRAY_ALPHA
+ (bit depths 8, 16)
+ PNG_COLOR_TYPE_PALETTE
+ (bit depths 1, 2, 4, 8)
+ PNG_COLOR_TYPE_RGB
+ (bit_depths 8, 16)
+ PNG_COLOR_TYPE_RGB_ALPHA
+ (bit_depths 8, 16)
+
+ PNG_COLOR_MASK_PALETTE
+ PNG_COLOR_MASK_COLOR
+ PNG_COLOR_MASK_ALPHA
+
+ interlace_type - (PNG_INTERLACE_NONE or
+ PNG_INTERLACE_ADAM7)
+
+ compression_type - (must be PNG_COMPRESSION_TYPE_BASE
+ for PNG 1.0)
+
+ filter_method - (must be PNG_FILTER_TYPE_BASE
+ for PNG 1.0, and can also be
+ PNG_INTRAPIXEL_DIFFERENCING if
+ the PNG datastream is embedded in
+ a MNG-1.0 datastream)
+
+ Any of width, height, color_type, bit_depth,
+ interlace_type, compression_type, or filter_method can
+ be NULL if you are not interested in their values.
+
+ Note that png_get_IHDR() returns 32-bit data into
+ the application's width and height variables.
+ This is an unsafe situation if these are not png_uint_32
+ variables. In such situations, the
+ png_get_image_width() and png_get_image_height()
+ functions described below are safer.
+
+ width = png_get_image_width(png_ptr,
+ info_ptr);
+
+ height = png_get_image_height(png_ptr,
+ info_ptr);
+
+ bit_depth = png_get_bit_depth(png_ptr,
+ info_ptr);
+
+ color_type = png_get_color_type(png_ptr,
+ info_ptr);
+
+ interlace_type = png_get_interlace_type(png_ptr,
+ info_ptr);
+
+ compression_type = png_get_compression_type(png_ptr,
+ info_ptr);
+
+ filter_method = png_get_filter_type(png_ptr,
+ info_ptr);
+
+ channels = png_get_channels(png_ptr, info_ptr);
+
+ channels - number of channels of info for the
+ color type (valid values are 1 (GRAY,
+ PALETTE), 2 (GRAY_ALPHA), 3 (RGB),
+ 4 (RGB_ALPHA or RGB + filler byte))
+
+ rowbytes = png_get_rowbytes(png_ptr, info_ptr);
+
+ rowbytes - number of bytes needed to hold a row
+
+ signature = png_get_signature(png_ptr, info_ptr);
+
+ signature - holds the signature read from the
+ file (if any). The data is kept in
+ the same offset it would be if the
+ whole signature were read (i.e. if an
+ application had already read in 4
+ bytes of signature before starting
+ libpng, the remaining 4 bytes would
+ be in signature[4] through signature[7]
+ (see png_set_sig_bytes())).
+
+These are also important, but their validity depends on whether the chunk
+has been read. The png_get_valid(png_ptr, info_ptr, PNG_INFO_<chunk>) and
+png_get_<chunk>(png_ptr, info_ptr, ...) functions return non-zero if the
+data has been read, or zero if it is missing. The parameters to the
+png_get_<chunk> are set directly if they are simple data types, or a
+pointer into the info_ptr is returned for any complex types.
+
+The colorspace data from gAMA, cHRM, sRGB, iCCP, and sBIT chunks
+is simply returned to give the application information about how the
+image was encoded. Libpng itself only does transformations using the file
+gamma when combining semitransparent pixels with the background color, and,
+since libpng-1.6.0, when converting between 8-bit sRGB and 16-bit linear pixels
+within the simplified API. Libpng also uses the file gamma when converting
+RGB to gray, beginning with libpng-1.0.5, if the application calls
+png_set_rgb_to_gray()).
+
+ png_get_PLTE(png_ptr, info_ptr, &palette,
+ &num_palette);
+
+ palette - the palette for the file
+ (array of png_color)
+
+ num_palette - number of entries in the palette
+
+ png_get_gAMA(png_ptr, info_ptr, &file_gamma);
+ png_get_gAMA_fixed(png_ptr, info_ptr, &int_file_gamma);
+
+ file_gamma - the gamma at which the file is
+ written (PNG_INFO_gAMA)
+
+ int_file_gamma - 100,000 times the gamma at which the
+ file is written
+
+ png_get_cHRM(png_ptr, info_ptr, &white_x, &white_y, &red_x,
+ &red_y, &green_x, &green_y, &blue_x, &blue_y)
+ png_get_cHRM_XYZ(png_ptr, info_ptr, &red_X, &red_Y, &red_Z,
+ &green_X, &green_Y, &green_Z, &blue_X, &blue_Y,
+ &blue_Z)
+ png_get_cHRM_fixed(png_ptr, info_ptr, &int_white_x,
+ &int_white_y, &int_red_x, &int_red_y,
+ &int_green_x, &int_green_y, &int_blue_x,
+ &int_blue_y)
+ png_get_cHRM_XYZ_fixed(png_ptr, info_ptr, &int_red_X, &int_red_Y,
+ &int_red_Z, &int_green_X, &int_green_Y,
+ &int_green_Z, &int_blue_X, &int_blue_Y,
+ &int_blue_Z)
+
+ {white,red,green,blue}_{x,y}
+ A color space encoding specified using the
+ chromaticities of the end points and the
+ white point. (PNG_INFO_cHRM)
+
+ {red,green,blue}_{X,Y,Z}
+ A color space encoding specified using the
+ encoding end points - the CIE tristimulus
+ specification of the intended color of the red,
+ green and blue channels in the PNG RGB data.
+ The white point is simply the sum of the three
+ end points. (PNG_INFO_cHRM)
+
+ png_get_sRGB(png_ptr, info_ptr, &srgb_intent);
+
+ srgb_intent - the rendering intent (PNG_INFO_sRGB)
+ The presence of the sRGB chunk
+ means that the pixel data is in the
+ sRGB color space. This chunk also
+ implies specific values of gAMA and
+ cHRM.
+
+ png_get_iCCP(png_ptr, info_ptr, &name,
+ &compression_type, &profile, &proflen);
+
+ name - The profile name.
+
+ compression_type - The compression type; always
+ PNG_COMPRESSION_TYPE_BASE for PNG 1.0.
+ You may give NULL to this argument to
+ ignore it.
+
+ profile - International Color Consortium color
+ profile data. May contain NULs.
+
+ proflen - length of profile data in bytes.
+
+ png_get_sBIT(png_ptr, info_ptr, &sig_bit);
+
+ sig_bit - the number of significant bits for
+ (PNG_INFO_sBIT) each of the gray,
+ red, green, and blue channels,
+ whichever are appropriate for the
+ given color type (png_color_16)
+
+ png_get_tRNS(png_ptr, info_ptr, &trans_alpha,
+ &num_trans, &trans_color);
+
+ trans_alpha - array of alpha (transparency)
+ entries for palette (PNG_INFO_tRNS)
+
+ num_trans - number of transparent entries
+ (PNG_INFO_tRNS)
+
+ trans_color - graylevel or color sample values of
+ the single transparent color for
+ non-paletted images (PNG_INFO_tRNS)
+
+ png_get_hIST(png_ptr, info_ptr, &hist);
+ (PNG_INFO_hIST)
+
+ hist - histogram of palette (array of
+ png_uint_16)
+
+ png_get_tIME(png_ptr, info_ptr, &mod_time);
+
+ mod_time - time image was last modified
+ (PNG_VALID_tIME)
+
+ png_get_bKGD(png_ptr, info_ptr, &background);
+
+ background - background color (of type
+ png_color_16p) (PNG_VALID_bKGD)
+ valid 16-bit red, green and blue
+ values, regardless of color_type
+
+ num_comments = png_get_text(png_ptr, info_ptr,
+ &text_ptr, &num_text);
+
+ num_comments - number of comments
+
+ text_ptr - array of png_text holding image
+ comments
+
+ text_ptr[i].compression - type of compression used
+ on "text" PNG_TEXT_COMPRESSION_NONE
+ PNG_TEXT_COMPRESSION_zTXt
+ PNG_ITXT_COMPRESSION_NONE
+ PNG_ITXT_COMPRESSION_zTXt
+
+ text_ptr[i].key - keyword for comment. Must contain
+ 1-79 characters.
+
+ text_ptr[i].text - text comments for current
+ keyword. Can be empty.
+
+ text_ptr[i].text_length - length of text string,
+ after decompression, 0 for iTXt
+
+ text_ptr[i].itxt_length - length of itxt string,
+ after decompression, 0 for tEXt/zTXt
+
+ text_ptr[i].lang - language of comment (empty
+ string for unknown).
+
+ text_ptr[i].lang_key - keyword in UTF-8
+ (empty string for unknown).
+
+ Note that the itxt_length, lang, and lang_key
+ members of the text_ptr structure only exist when the
+ library is built with iTXt chunk support. Prior to
+ libpng-1.4.0 the library was built by default without
+ iTXt support. Also note that when iTXt is supported,
+ they contain NULL pointers when the "compression"
+ field contains PNG_TEXT_COMPRESSION_NONE or
+ PNG_TEXT_COMPRESSION_zTXt.
+
+ num_text - number of comments (same as
+ num_comments; you can put NULL here
+ to avoid the duplication)
+
+ Note while png_set_text() will accept text, language,
+ and translated keywords that can be NULL pointers, the
+ structure returned by png_get_text will always contain
+ regular zero-terminated C strings. They might be
+ empty strings but they will never be NULL pointers.
+
+ num_spalettes = png_get_sPLT(png_ptr, info_ptr,
+ &palette_ptr);
+
+ num_spalettes - number of sPLT chunks read.
+
+ palette_ptr - array of palette structures holding
+ contents of one or more sPLT chunks
+ read.
+
+ png_get_oFFs(png_ptr, info_ptr, &offset_x, &offset_y,
+ &unit_type);
+
+ offset_x - positive offset from the left edge
+ of the screen (can be negative)
+
+ offset_y - positive offset from the top edge
+ of the screen (can be negative)
+
+ unit_type - PNG_OFFSET_PIXEL, PNG_OFFSET_MICROMETER
+
+ png_get_pHYs(png_ptr, info_ptr, &res_x, &res_y,
+ &unit_type);
+
+ res_x - pixels/unit physical resolution in
+ x direction
+
+ res_y - pixels/unit physical resolution in
+ x direction
+
+ unit_type - PNG_RESOLUTION_UNKNOWN,
+ PNG_RESOLUTION_METER
+
+ png_get_sCAL(png_ptr, info_ptr, &unit, &width,
+ &height)
+
+ unit - physical scale units (an integer)
+
+ width - width of a pixel in physical scale units
+
+ height - height of a pixel in physical scale units
+ (width and height are doubles)
+
+ png_get_sCAL_s(png_ptr, info_ptr, &unit, &width,
+ &height)
+
+ unit - physical scale units (an integer)
+
+ width - width of a pixel in physical scale units
+ (expressed as a string)
+
+ height - height of a pixel in physical scale units
+ (width and height are strings like "2.54")
+
+ num_unknown_chunks = png_get_unknown_chunks(png_ptr,
+ info_ptr, &unknowns)
+
+ unknowns - array of png_unknown_chunk
+ structures holding unknown chunks
+
+ unknowns[i].name - name of unknown chunk
+
+ unknowns[i].data - data of unknown chunk
+
+ unknowns[i].size - size of unknown chunk's data
+
+ unknowns[i].location - position of chunk in file
+
+ The value of "i" corresponds to the order in which the
+ chunks were read from the PNG file or inserted with the
+ png_set_unknown_chunks() function.
+
+ The value of "location" is a bitwise "or" of
+
+ PNG_HAVE_IHDR (0x01)
+ PNG_HAVE_PLTE (0x02)
+ PNG_AFTER_IDAT (0x08)
+
+The data from the pHYs chunk can be retrieved in several convenient
+forms:
+
+ res_x = png_get_x_pixels_per_meter(png_ptr,
+ info_ptr)
+
+ res_y = png_get_y_pixels_per_meter(png_ptr,
+ info_ptr)
+
+ res_x_and_y = png_get_pixels_per_meter(png_ptr,
+ info_ptr)
+
+ res_x = png_get_x_pixels_per_inch(png_ptr,
+ info_ptr)
+
+ res_y = png_get_y_pixels_per_inch(png_ptr,
+ info_ptr)
+
+ res_x_and_y = png_get_pixels_per_inch(png_ptr,
+ info_ptr)
+
+ aspect_ratio = png_get_pixel_aspect_ratio(png_ptr,
+ info_ptr)
+
+ Each of these returns 0 [signifying "unknown"] if
+ the data is not present or if res_x is 0;
+ res_x_and_y is 0 if res_x != res_y
+
+ Note that because of the way the resolutions are
+ stored internally, the inch conversions won't
+ come out to exactly even number. For example,
+ 72 dpi is stored as 0.28346 pixels/meter, and
+ when this is retrieved it is 71.9988 dpi, so
+ be sure to round the returned value appropriately
+ if you want to display a reasonable-looking result.
+
+The data from the oFFs chunk can be retrieved in several convenient
+forms:
+
+ x_offset = png_get_x_offset_microns(png_ptr, info_ptr);
+
+ y_offset = png_get_y_offset_microns(png_ptr, info_ptr);
+
+ x_offset = png_get_x_offset_inches(png_ptr, info_ptr);
+
+ y_offset = png_get_y_offset_inches(png_ptr, info_ptr);
+
+ Each of these returns 0 [signifying "unknown" if both
+ x and y are 0] if the data is not present or if the
+ chunk is present but the unit is the pixel. The
+ remark about inexact inch conversions applies here
+ as well, because a value in inches can't always be
+ converted to microns and back without some loss
+ of precision.
+
+For more information, see the
+PNG specification for chunk contents. Be careful with trusting
+rowbytes, as some of the transformations could increase the space
+needed to hold a row (expand, filler, gray_to_rgb, etc.).
+See png_read_update_info(), below.
+
+A quick word about text_ptr and num_text. PNG stores comments in
+keyword/text pairs, one pair per chunk, with no limit on the number
+of text chunks, and a 2^31 byte limit on their size. While there are
+suggested keywords, there is no requirement to restrict the use to these
+strings. It is strongly suggested that keywords and text be sensible
+to humans (that's the point), so don't use abbreviations. Non-printing
+symbols are not allowed. See the PNG specification for more details.
+There is also no requirement to have text after the keyword.
+
+Keywords should be limited to 79 Latin-1 characters without leading or
+trailing spaces, but non-consecutive spaces are allowed within the
+keyword. It is possible to have the same keyword any number of times.
+The text_ptr is an array of png_text structures, each holding a
+pointer to a language string, a pointer to a keyword and a pointer to
+a text string. The text string, language code, and translated
+keyword may be empty or NULL pointers. The keyword/text
+pairs are put into the array in the order that they are received.
+However, some or all of the text chunks may be after the image, so, to
+make sure you have read all the text chunks, don't mess with these
+until after you read the stuff after the image. This will be
+mentioned again below in the discussion that goes with png_read_end().
+
+Input transformations
+
+After you've read the header information, you can set up the library
+to handle any special transformations of the image data. The various
+ways to transform the data will be described in the order that they
+should occur. This is important, as some of these change the color
+type and/or bit depth of the data, and some others only work on
+certain color types and bit depths.
+
+Transformations you request are ignored if they don't have any meaning for a
+particular input data format. However some transformations can have an effect
+as a result of a previous transformation. If you specify a contradictory set of
+transformations, for example both adding and removing the alpha channel, you
+cannot predict the final result.
+
+The color used for the transparency values should be supplied in the same
+format/depth as the current image data. It is stored in the same format/depth
+as the image data in a tRNS chunk, so this is what libpng expects for this data.
+
+The color used for the background value depends on the need_expand argument as
+described below.
+
+Data will be decoded into the supplied row buffers packed into bytes
+unless the library has been told to transform it into another format.
+For example, 4 bit/pixel paletted or grayscale data will be returned
+2 pixels/byte with the leftmost pixel in the high-order bits of the
+byte, unless png_set_packing() is called. 8-bit RGB data will be stored
+in RGB RGB RGB format unless png_set_filler() or png_set_add_alpha()
+is called to insert filler bytes, either before or after each RGB triplet.
+16-bit RGB data will be returned RRGGBB RRGGBB, with the most significant
+byte of the color value first, unless png_set_scale_16() is called to
+transform it to regular RGB RGB triplets, or png_set_filler() or
+png_set_add alpha() is called to insert filler bytes, either before or
+after each RRGGBB triplet. Similarly, 8-bit or 16-bit grayscale data can
+be modified with png_set_filler(), png_set_add_alpha(), png_set_strip_16(),
+or png_set_scale_16().
+
+The following code transforms grayscale images of less than 8 to 8 bits,
+changes paletted images to RGB, and adds a full alpha channel if there is
+transparency information in a tRNS chunk. This is most useful on
+grayscale images with bit depths of 2 or 4 or if there is a multiple-image
+viewing application that wishes to treat all images in the same way.
+
+ if (color_type == PNG_COLOR_TYPE_PALETTE)
+ png_set_palette_to_rgb(png_ptr);
+
+ if (png_get_valid(png_ptr, info_ptr,
+ PNG_INFO_tRNS)) png_set_tRNS_to_alpha(png_ptr);
+
+ if (color_type == PNG_COLOR_TYPE_GRAY &&
+ bit_depth < 8) png_set_expand_gray_1_2_4_to_8(png_ptr);
+
+The first two functions are actually aliases for png_set_expand(), added
+in libpng version 1.0.4, with the function names expanded to improve code
+readability. In some future version they may actually do different
+things.
+
+As of libpng version 1.2.9, png_set_expand_gray_1_2_4_to_8() was
+added. It expands the sample depth without changing tRNS to alpha.
+
+As of libpng version 1.5.2, png_set_expand_16() was added. It behaves as
+png_set_expand(); however, the resultant channels have 16 bits rather than 8.
+Use this when the output color or gray channels are made linear to avoid fairly
+severe accuracy loss.
+
+ if (bit_depth < 16)
+ png_set_expand_16(png_ptr);
+
+PNG can have files with 16 bits per channel. If you only can handle
+8 bits per channel, this will strip the pixels down to 8-bit.
+
+ if (bit_depth == 16)
+#if PNG_LIBPNG_VER >= 10504
+ png_set_scale_16(png_ptr);
+#else
+ png_set_strip_16(png_ptr);
+#endif
+
+(The more accurate "png_set_scale_16()" API became available in libpng version
+1.5.4).
+
+If you need to process the alpha channel on the image separately from the image
+data (for example if you convert it to a bitmap mask) it is possible to have
+libpng strip the channel leaving just RGB or gray data:
+
+ if (color_type & PNG_COLOR_MASK_ALPHA)
+ png_set_strip_alpha(png_ptr);
+
+If you strip the alpha channel you need to find some other way of dealing with
+the information. If, instead, you want to convert the image to an opaque
+version with no alpha channel use png_set_background; see below.
+
+As of libpng version 1.5.2, almost all useful expansions are supported, the
+major ommissions are conversion of grayscale to indexed images (which can be
+done trivially in the application) and conversion of indexed to grayscale (which
+can be done by a trivial manipulation of the palette.)
+
+In the following table, the 01 means grayscale with depth<8, 31 means
+indexed with depth<8, other numerals represent the color type, "T" means
+the tRNS chunk is present, A means an alpha channel is present, and O
+means tRNS or alpha is present but all pixels in the image are opaque.
+
+ FROM 01 31 0 0T 0O 2 2T 2O 3 3T 3O 4A 4O 6A 6O
+ TO
+ 01 - [G] - - - - - - - - - - - - -
+ 31 [Q] Q [Q] [Q] [Q] Q Q Q Q Q Q [Q] [Q] Q Q
+ 0 1 G + . . G G G G G G B B GB GB
+ 0T lt Gt t + . Gt G G Gt G G Bt Bt GBt GBt
+ 0O lt Gt t . + Gt Gt G Gt Gt G Bt Bt GBt GBt
+ 2 C P C C C + . . C - - CB CB B B
+ 2T Ct - Ct C C t + t - - - CBt CBt Bt Bt
+ 2O Ct - Ct C C t t + - - - CBt CBt Bt Bt
+ 3 [Q] p [Q] [Q] [Q] Q Q Q + . . [Q] [Q] Q Q
+ 3T [Qt] p [Qt][Q] [Q] Qt Qt Qt t + t [Qt][Qt] Qt Qt
+ 3O [Qt] p [Qt][Q] [Q] Qt Qt Qt t t + [Qt][Qt] Qt Qt
+ 4A lA G A T T GA GT GT GA GT GT + BA G GBA
+ 4O lA GBA A T T GA GT GT GA GT GT BA + GBA G
+ 6A CA PA CA C C A T tT PA P P C CBA + BA
+ 6O CA PBA CA C C A tT T PA P P CBA C BA +
+
+Within the matrix,
+ "+" identifies entries where 'from' and 'to' are the same.
+ "-" means the transformation is not supported.
+ "." means nothing is necessary (a tRNS chunk can just be ignored).
+ "t" means the transformation is obtained by png_set_tRNS.
+ "A" means the transformation is obtained by png_set_add_alpha().
+ "X" means the transformation is obtained by png_set_expand().
+ "1" means the transformation is obtained by
+ png_set_expand_gray_1_2_4_to_8() (and by png_set_expand()
+ if there is no transparency in the original or the final
+ format).
+ "C" means the transformation is obtained by png_set_gray_to_rgb().
+ "G" means the transformation is obtained by png_set_rgb_to_gray().
+ "P" means the transformation is obtained by
+ png_set_expand_palette_to_rgb().
+ "p" means the transformation is obtained by png_set_packing().
+ "Q" means the transformation is obtained by png_set_quantize().
+ "T" means the transformation is obtained by
+ png_set_tRNS_to_alpha().
+ "B" means the transformation is obtained by
+ png_set_background(), or png_strip_alpha().
+
+When an entry has multiple transforms listed all are required to cause the
+right overall transformation. When two transforms are separated by a comma
+either will do the job. When transforms are enclosed in [] the transform should
+do the job but this is currently unimplemented - a different format will result
+if the suggested transformations are used.
+
+In PNG files, the alpha channel in an image
+is the level of opacity. If you need the alpha channel in an image to
+be the level of transparency instead of opacity, you can invert the
+alpha channel (or the tRNS chunk data) after it's read, so that 0 is
+fully opaque and 255 (in 8-bit or paletted images) or 65535 (in 16-bit
+images) is fully transparent, with
+
+ png_set_invert_alpha(png_ptr);
+
+PNG files pack pixels of bit depths 1, 2, and 4 into bytes as small as
+they can, resulting in, for example, 8 pixels per byte for 1 bit
+files. This code expands to 1 pixel per byte without changing the
+values of the pixels:
+
+ if (bit_depth < 8)
+ png_set_packing(png_ptr);
+
+PNG files have possible bit depths of 1, 2, 4, 8, and 16. All pixels
+stored in a PNG image have been "scaled" or "shifted" up to the next
+higher possible bit depth (e.g. from 5 bits/sample in the range [0,31]
+to 8 bits/sample in the range [0, 255]). However, it is also possible
+to convert the PNG pixel data back to the original bit depth of the
+image. This call reduces the pixels back down to the original bit depth:
+
+ png_color_8p sig_bit;
+
+ if (png_get_sBIT(png_ptr, info_ptr, &sig_bit))
+ png_set_shift(png_ptr, sig_bit);
+
+PNG files store 3-color pixels in red, green, blue order. This code
+changes the storage of the pixels to blue, green, red:
+
+ if (color_type == PNG_COLOR_TYPE_RGB ||
+ color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+ png_set_bgr(png_ptr);
+
+PNG files store RGB pixels packed into 3 or 6 bytes. This code expands them
+into 4 or 8 bytes for windowing systems that need them in this format:
+
+ if (color_type == PNG_COLOR_TYPE_RGB)
+ png_set_filler(png_ptr, filler, PNG_FILLER_BEFORE);
+
+where "filler" is the 8 or 16-bit number to fill with, and the location is
+either PNG_FILLER_BEFORE or PNG_FILLER_AFTER, depending upon whether
+you want the filler before the RGB or after. This transformation
+does not affect images that already have full alpha channels. To add an
+opaque alpha channel, use filler=0xff or 0xffff and PNG_FILLER_AFTER which
+will generate RGBA pixels.
+
+Note that png_set_filler() does not change the color type. If you want
+to do that, you can add a true alpha channel with
+
+ if (color_type == PNG_COLOR_TYPE_RGB ||
+ color_type == PNG_COLOR_TYPE_GRAY)
+ png_set_add_alpha(png_ptr, filler, PNG_FILLER_AFTER);
+
+where "filler" contains the alpha value to assign to each pixel.
+This function was added in libpng-1.2.7.
+
+If you are reading an image with an alpha channel, and you need the
+data as ARGB instead of the normal PNG format RGBA:
+
+ if (color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+ png_set_swap_alpha(png_ptr);
+
+For some uses, you may want a grayscale image to be represented as
+RGB. This code will do that conversion:
+
+ if (color_type == PNG_COLOR_TYPE_GRAY ||
+ color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
+ png_set_gray_to_rgb(png_ptr);
+
+Conversely, you can convert an RGB or RGBA image to grayscale or grayscale
+with alpha.
+
+ if (color_type == PNG_COLOR_TYPE_RGB ||
+ color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+ png_set_rgb_to_gray(png_ptr, error_action,
+ double red_weight, double green_weight);
+
+ error_action = 1: silently do the conversion
+
+ error_action = 2: issue a warning if the original
+ image has any pixel where
+ red != green or red != blue
+
+ error_action = 3: issue an error and abort the
+ conversion if the original
+ image has any pixel where
+ red != green or red != blue
+
+ red_weight: weight of red component
+
+ green_weight: weight of green component
+ If either weight is negative, default
+ weights are used.
+
+In the corresponding fixed point API the red_weight and green_weight values are
+simply scaled by 100,000:
+
+ png_set_rgb_to_gray(png_ptr, error_action,
+ png_fixed_point red_weight,
+ png_fixed_point green_weight);
+
+If you have set error_action = 1 or 2, you can
+later check whether the image really was gray, after processing
+the image rows, with the png_get_rgb_to_gray_status(png_ptr) function.
+It will return a png_byte that is zero if the image was gray or
+1 if there were any non-gray pixels. Background and sBIT data
+will be silently converted to grayscale, using the green channel
+data for sBIT, regardless of the error_action setting.
+
+The default values come from the PNG file cHRM chunk if present; otherwise, the
+defaults correspond to the ITU-R recommendation 709, and also the sRGB color
+space, as recommended in the Charles Poynton's Colour FAQ,
+<http://www.poynton.com/>, in section 9:
+
+ <http://www.poynton.com/notes/colour_and_gamma/ColorFAQ.html#RTFToC9>
+
+ Y = 0.2126 * R + 0.7152 * G + 0.0722 * B
+
+Previous versions of this document, 1998 through 2002, recommended a slightly
+different formula:
+
+ Y = 0.212671 * R + 0.715160 * G + 0.072169 * B
+
+Libpng uses an integer approximation:
+
+ Y = (6968 * R + 23434 * G + 2366 * B)/32768
+
+The calculation is done in a linear colorspace, if the image gamma
+can be determined.
+
+The png_set_background() function has been described already; it tells libpng to
+composite images with alpha or simple transparency against the supplied
+background color. For compatibility with versions of libpng earlier than
+libpng-1.5.4 it is recommended that you call the function after reading the file
+header, even if you don't want to use the color in a bKGD chunk, if one exists.
+
+If the PNG file contains a bKGD chunk (PNG_INFO_bKGD valid),
+you may use this color, or supply another color more suitable for
+the current display (e.g., the background color from a web page). You
+need to tell libpng how the color is represented, both the format of the
+component values in the color (the number of bits) and the gamma encoding of the
+color. The function takes two arguments, background_gamma_mode and need_expand
+to convey this information; however, only two combinations are likely to be
+useful:
+
+ png_color_16 my_background;
+ png_color_16p image_background;
+
+ if (png_get_bKGD(png_ptr, info_ptr, &image_background))
+ png_set_background(png_ptr, image_background,
+ PNG_BACKGROUND_GAMMA_FILE, 1/*needs to be expanded*/, 1);
+ else
+ png_set_background(png_ptr, &my_background,
+ PNG_BACKGROUND_GAMMA_SCREEN, 0/*do not expand*/, 1);
+
+The second call was described above - my_background is in the format of the
+final, display, output produced by libpng. Because you now know the format of
+the PNG it is possible to avoid the need to choose either 8-bit or 16-bit
+output and to retain palette images (the palette colors will be modified
+appropriately and the tRNS chunk removed.) However, if you are doing this,
+take great care not to ask for transformations without checking first that
+they apply!
+
+In the first call the background color has the original bit depth and color type
+of the PNG file. So, for palette images the color is supplied as a palette
+index and for low bit greyscale images the color is a reduced bit value in
+image_background->gray.
+
+If you didn't call png_set_gamma() before reading the file header, for example
+if you need your code to remain compatible with older versions of libpng prior
+to libpng-1.5.4, this is the place to call it.
+
+Do not call it if you called png_set_alpha_mode(); doing so will damage the
+settings put in place by png_set_alpha_mode(). (If png_set_alpha_mode() is
+supported then you can certainly do png_set_gamma() before reading the PNG
+header.)
+
+This API unconditionally sets the screen and file gamma values, so it will
+override the value in the PNG file unless it is called before the PNG file
+reading starts. For this reason you must always call it with the PNG file
+value when you call it in this position:
+
+ if (png_get_gAMA(png_ptr, info_ptr, &file_gamma))
+ png_set_gamma(png_ptr, screen_gamma, file_gamma);
+
+ else
+ png_set_gamma(png_ptr, screen_gamma, 0.45455);
+
+If you need to reduce an RGB file to a paletted file, or if a paletted
+file has more entries than will fit on your screen, png_set_quantize()
+will do that. Note that this is a simple match quantization that merely
+finds the closest color available. This should work fairly well with
+optimized palettes, but fairly badly with linear color cubes. If you
+pass a palette that is larger than maximum_colors, the file will
+reduce the number of colors in the palette so it will fit into
+maximum_colors. If there is a histogram, libpng will use it to make
+more intelligent choices when reducing the palette. If there is no
+histogram, it may not do as good a job.
+
+ if (color_type & PNG_COLOR_MASK_COLOR)
+ {
+ if (png_get_valid(png_ptr, info_ptr,
+ PNG_INFO_PLTE))
+ {
+ png_uint_16p histogram = NULL;
+
+ png_get_hIST(png_ptr, info_ptr,
+ &histogram);
+ png_set_quantize(png_ptr, palette, num_palette,
+ max_screen_colors, histogram, 1);
+ }
+
+ else
+ {
+ png_color std_color_cube[MAX_SCREEN_COLORS] =
+ { ... colors ... };
+
+ png_set_quantize(png_ptr, std_color_cube,
+ MAX_SCREEN_COLORS, MAX_SCREEN_COLORS,
+ NULL,0);
+ }
+ }
+
+PNG files describe monochrome as black being zero and white being one.
+The following code will reverse this (make black be one and white be
+zero):
+
+ if (bit_depth == 1 && color_type == PNG_COLOR_TYPE_GRAY)
+ png_set_invert_mono(png_ptr);
+
+This function can also be used to invert grayscale and gray-alpha images:
+
+ if (color_type == PNG_COLOR_TYPE_GRAY ||
+ color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
+ png_set_invert_mono(png_ptr);
+
+PNG files store 16-bit pixels in network byte order (big-endian,
+ie. most significant bits first). This code changes the storage to the
+other way (little-endian, i.e. least significant bits first, the
+way PCs store them):
+
+ if (bit_depth == 16)
+ png_set_swap(png_ptr);
+
+If you are using packed-pixel images (1, 2, or 4 bits/pixel), and you
+need to change the order the pixels are packed into bytes, you can use:
+
+ if (bit_depth < 8)
+ png_set_packswap(png_ptr);
+
+Finally, you can write your own transformation function if none of
+the existing ones meets your needs. This is done by setting a callback
+with
+
+ png_set_read_user_transform_fn(png_ptr,
+ read_transform_fn);
+
+You must supply the function
+
+ void read_transform_fn(png_structp png_ptr, png_row_infop
+ row_info, png_bytep data)
+
+See pngtest.c for a working example. Your function will be called
+after all of the other transformations have been processed. Take care with
+interlaced images if you do the interlace yourself - the width of the row is the
+width in 'row_info', not the overall image width.
+
+If supported, libpng provides two information routines that you can use to find
+where you are in processing the image:
+
+ png_get_current_pass_number(png_structp png_ptr);
+ png_get_current_row_number(png_structp png_ptr);
+
+Don't try using these outside a transform callback - firstly they are only
+supported if user transforms are supported, secondly they may well return
+unexpected results unless the row is actually being processed at the moment they
+are called.
+
+With interlaced
+images the value returned is the row in the input sub-image image. Use
+PNG_ROW_FROM_PASS_ROW(row, pass) and PNG_COL_FROM_PASS_COL(col, pass) to
+find the output pixel (x,y) given an interlaced sub-image pixel (row,col,pass).
+
+The discussion of interlace handling above contains more information on how to
+use these values.
+
+You can also set up a pointer to a user structure for use by your
+callback function, and you can inform libpng that your transform
+function will change the number of channels or bit depth with the
+function
+
+ png_set_user_transform_info(png_ptr, user_ptr,
+ user_depth, user_channels);
+
+The user's application, not libpng, is responsible for allocating and
+freeing any memory required for the user structure.
+
+You can retrieve the pointer via the function
+png_get_user_transform_ptr(). For example:
+
+ voidp read_user_transform_ptr =
+ png_get_user_transform_ptr(png_ptr);
+
+The last thing to handle is interlacing; this is covered in detail below,
+but you must call the function here if you want libpng to handle expansion
+of the interlaced image.
+
+ number_of_passes = png_set_interlace_handling(png_ptr);
+
+After setting the transformations, libpng can update your png_info
+structure to reflect any transformations you've requested with this
+call.
+
+ png_read_update_info(png_ptr, info_ptr);
+
+This is most useful to update the info structure's rowbytes
+field so you can use it to allocate your image memory. This function
+will also update your palette with the correct screen_gamma and
+background if these have been given with the calls above. You may
+only call png_read_update_info() once with a particular info_ptr.
+
+After you call png_read_update_info(), you can allocate any
+memory you need to hold the image. The row data is simply
+raw byte data for all forms of images. As the actual allocation
+varies among applications, no example will be given. If you
+are allocating one large chunk, you will need to build an
+array of pointers to each row, as it will be needed for some
+of the functions below.
+
+Remember: Before you call png_read_update_info(), the png_get_*()
+functions return the values corresponding to the original PNG image.
+After you call png_read_update_info the values refer to the image
+that libpng will output. Consequently you must call all the png_set_
+functions before you call png_read_update_info(). This is particularly
+important for png_set_interlace_handling() - if you are going to call
+png_read_update_info() you must call png_set_interlace_handling() before
+it unless you want to receive interlaced output.
+
+Reading image data
+
+After you've allocated memory, you can read the image data.
+The simplest way to do this is in one function call. If you are
+allocating enough memory to hold the whole image, you can just
+call png_read_image() and libpng will read in all the image data
+and put it in the memory area supplied. You will need to pass in
+an array of pointers to each row.
+
+This function automatically handles interlacing, so you don't
+need to call png_set_interlace_handling() (unless you call
+png_read_update_info()) or call this function multiple times, or any
+of that other stuff necessary with png_read_rows().
+
+ png_read_image(png_ptr, row_pointers);
+
+where row_pointers is:
+
+ png_bytep row_pointers[height];
+
+You can point to void or char or whatever you use for pixels.
+
+If you don't want to read in the whole image at once, you can
+use png_read_rows() instead. If there is no interlacing (check
+interlace_type == PNG_INTERLACE_NONE), this is simple:
+
+ png_read_rows(png_ptr, row_pointers, NULL,
+ number_of_rows);
+
+where row_pointers is the same as in the png_read_image() call.
+
+If you are doing this just one row at a time, you can do this with
+a single row_pointer instead of an array of row_pointers:
+
+ png_bytep row_pointer = row;
+ png_read_row(png_ptr, row_pointer, NULL);
+
+If the file is interlaced (interlace_type != 0 in the IHDR chunk), things
+get somewhat harder. The only current (PNG Specification version 1.2)
+interlacing type for PNG is (interlace_type == PNG_INTERLACE_ADAM7);
+a somewhat complicated 2D interlace scheme, known as Adam7, that
+breaks down an image into seven smaller images of varying size, based
+on an 8x8 grid. This number is defined (from libpng 1.5) as
+PNG_INTERLACE_ADAM7_PASSES in png.h
+
+libpng can fill out those images or it can give them to you "as is".
+It is almost always better to have libpng handle the interlacing for you.
+If you want the images filled out, there are two ways to do that. The one
+mentioned in the PNG specification is to expand each pixel to cover
+those pixels that have not been read yet (the "rectangle" method).
+This results in a blocky image for the first pass, which gradually
+smooths out as more pixels are read. The other method is the "sparkle"
+method, where pixels are drawn only in their final locations, with the
+rest of the image remaining whatever colors they were initialized to
+before the start of the read. The first method usually looks better,
+but tends to be slower, as there are more pixels to put in the rows.
+
+If, as is likely, you want libpng to expand the images, call this before
+calling png_start_read_image() or png_read_update_info():
+
+ if (interlace_type == PNG_INTERLACE_ADAM7)
+ number_of_passes
+ = png_set_interlace_handling(png_ptr);
+
+This will return the number of passes needed. Currently, this is seven,
+but may change if another interlace type is added. This function can be
+called even if the file is not interlaced, where it will return one pass.
+You then need to read the whole image 'number_of_passes' times. Each time
+will distribute the pixels from the current pass to the correct place in
+the output image, so you need to supply the same rows to png_read_rows in
+each pass.
+
+If you are not going to display the image after each pass, but are
+going to wait until the entire image is read in, use the sparkle
+effect. This effect is faster and the end result of either method
+is exactly the same. If you are planning on displaying the image
+after each pass, the "rectangle" effect is generally considered the
+better looking one.
+
+If you only want the "sparkle" effect, just call png_read_rows() as
+normal, with the third parameter NULL. Make sure you make pass over
+the image number_of_passes times, and you don't change the data in the
+rows between calls. You can change the locations of the data, just
+not the data. Each pass only writes the pixels appropriate for that
+pass, and assumes the data from previous passes is still valid.
+
+ png_read_rows(png_ptr, row_pointers, NULL,
+ number_of_rows);
+
+If you only want the first effect (the rectangles), do the same as
+before except pass the row buffer in the third parameter, and leave
+the second parameter NULL.
+
+ png_read_rows(png_ptr, NULL, row_pointers,
+ number_of_rows);
+
+If you don't want libpng to handle the interlacing details, just call
+png_read_rows() PNG_INTERLACE_ADAM7_PASSES times to read in all the images.
+Each of the images is a valid image by itself; however, you will almost
+certainly need to distribute the pixels from each sub-image to the
+correct place. This is where everything gets very tricky.
+
+If you want to retrieve the separate images you must pass the correct
+number of rows to each successive call of png_read_rows(). The calculation
+gets pretty complicated for small images, where some sub-images may
+not even exist because either their width or height ends up zero.
+libpng provides two macros to help you in 1.5 and later versions:
+
+ png_uint_32 width = PNG_PASS_COLS(image_width, pass_number);
+ png_uint_32 height = PNG_PASS_ROWS(image_height, pass_number);
+
+Respectively these tell you the width and height of the sub-image
+corresponding to the numbered pass. 'pass' is in in the range 0 to 6 -
+this can be confusing because the specification refers to the same passes
+as 1 to 7! Be careful, you must check both the width and height before
+calling png_read_rows() and not call it for that pass if either is zero.
+
+You can, of course, read each sub-image row by row. If you want to
+produce optimal code to make a pixel-by-pixel transformation of an
+interlaced image this is the best approach; read each row of each pass,
+transform it, and write it out to a new interlaced image.
+
+If you want to de-interlace the image yourself libpng provides further
+macros to help that tell you where to place the pixels in the output image.
+Because the interlacing scheme is rectangular - sub-image pixels are always
+arranged on a rectangular grid - all you need to know for each pass is the
+starting column and row in the output image of the first pixel plus the
+spacing between each pixel. As of libpng 1.5 there are four macros to
+retrieve this information:
+
+ png_uint_32 x = PNG_PASS_START_COL(pass);
+ png_uint_32 y = PNG_PASS_START_ROW(pass);
+ png_uint_32 xStep = 1U << PNG_PASS_COL_SHIFT(pass);
+ png_uint_32 yStep = 1U << PNG_PASS_ROW_SHIFT(pass);
+
+These allow you to write the obvious loop:
+
+ png_uint_32 input_y = 0;
+ png_uint_32 output_y = PNG_PASS_START_ROW(pass);
+
+ while (output_y < output_image_height)
+ {
+ png_uint_32 input_x = 0;
+ png_uint_32 output_x = PNG_PASS_START_COL(pass);
+
+ while (output_x < output_image_width)
+ {
+ image[output_y][output_x] =
+ subimage[pass][input_y][input_x++];
+
+ output_x += xStep;
+ }
+
+ ++input_y;
+ output_y += yStep;
+ }
+
+Notice that the steps between successive output rows and columns are
+returned as shifts. This is possible because the pixels in the subimages
+are always a power of 2 apart - 1, 2, 4 or 8 pixels - in the original
+image. In practice you may need to directly calculate the output coordinate
+given an input coordinate. libpng provides two further macros for this
+purpose:
+
+ png_uint_32 output_x = PNG_COL_FROM_PASS_COL(input_x, pass);
+ png_uint_32 output_y = PNG_ROW_FROM_PASS_ROW(input_y, pass);
+
+Finally a pair of macros are provided to tell you if a particular image
+row or column appears in a given pass:
+
+ int col_in_pass = PNG_COL_IN_INTERLACE_PASS(output_x, pass);
+ int row_in_pass = PNG_ROW_IN_INTERLACE_PASS(output_y, pass);
+
+Bear in mind that you will probably also need to check the width and height
+of the pass in addition to the above to be sure the pass even exists!
+
+With any luck you are convinced by now that you don't want to do your own
+interlace handling. In reality normally the only good reason for doing this
+is if you are processing PNG files on a pixel-by-pixel basis and don't want
+to load the whole file into memory when it is interlaced.
+
+libpng includes a test program, pngvalid, that illustrates reading and
+writing of interlaced images. If you can't get interlacing to work in your
+code and don't want to leave it to libpng (the recommended approach), see
+how pngvalid.c does it.
+
+Finishing a sequential read
+
+After you are finished reading the image through the
+low-level interface, you can finish reading the file.
+
+If you want to use a different crc action for handling CRC errors in
+chunks after the image data, you can call png_set_crc_action()
+again at this point.
+
+If you are interested in comments or time, which may be stored either
+before or after the image data, you should pass the separate png_info
+struct if you want to keep the comments from before and after the image
+separate.
+
+ png_infop end_info = png_create_info_struct(png_ptr);
+
+ if (!end_info)
+ {
+ png_destroy_read_struct(&png_ptr, &info_ptr,
+ (png_infopp)NULL);
+ return (ERROR);
+ }
+
+ png_read_end(png_ptr, end_info);
+
+If you are not interested, you should still call png_read_end()
+but you can pass NULL, avoiding the need to create an end_info structure.
+If you do this, libpng will not process any chunks after IDAT other than
+skipping over them and perhaps (depending on whether you have called
+png_set_crc_action) checking their CRCs while looking for the IEND chunk.
+
+ png_read_end(png_ptr, (png_infop)NULL);
+
+If you don't call png_read_end(), then your file pointer will be
+left pointing to the first chunk after the last IDAT, which is probably
+not what you want if you expect to read something beyond the end of
+the PNG datastream.
+
+When you are done, you can free all memory allocated by libpng like this:
+
+ png_destroy_read_struct(&png_ptr, &info_ptr,
+ &end_info);
+
+or, if you didn't create an end_info structure,
+
+ png_destroy_read_struct(&png_ptr, &info_ptr,
+ (png_infopp)NULL);
+
+It is also possible to individually free the info_ptr members that
+point to libpng-allocated storage with the following function:
+
+ png_free_data(png_ptr, info_ptr, mask, seq)
+
+ mask - identifies data to be freed, a mask
+ containing the bitwise OR of one or
+ more of
+ PNG_FREE_PLTE, PNG_FREE_TRNS,
+ PNG_FREE_HIST, PNG_FREE_ICCP,
+ PNG_FREE_PCAL, PNG_FREE_ROWS,
+ PNG_FREE_SCAL, PNG_FREE_SPLT,
+ PNG_FREE_TEXT, PNG_FREE_UNKN,
+ or simply PNG_FREE_ALL
+
+ seq - sequence number of item to be freed
+ (-1 for all items)
+
+This function may be safely called when the relevant storage has
+already been freed, or has not yet been allocated, or was allocated
+by the user and not by libpng, and will in those cases do nothing.
+The "seq" parameter is ignored if only one item of the selected data
+type, such as PLTE, is allowed. If "seq" is not -1, and multiple items
+are allowed for the data type identified in the mask, such as text or
+sPLT, only the n'th item in the structure is freed, where n is "seq".
+
+The default behavior is only to free data that was allocated internally
+by libpng. This can be changed, so that libpng will not free the data,
+or so that it will free data that was allocated by the user with png_malloc()
+or png_calloc() and passed in via a png_set_*() function, with
+
+ png_data_freer(png_ptr, info_ptr, freer, mask)
+
+ freer - one of
+ PNG_DESTROY_WILL_FREE_DATA
+ PNG_SET_WILL_FREE_DATA
+ PNG_USER_WILL_FREE_DATA
+
+ mask - which data elements are affected
+ same choices as in png_free_data()
+
+This function only affects data that has already been allocated.
+You can call this function after reading the PNG data but before calling
+any png_set_*() functions, to control whether the user or the png_set_*()
+function is responsible for freeing any existing data that might be present,
+and again after the png_set_*() functions to control whether the user
+or png_destroy_*() is supposed to free the data. When the user assumes
+responsibility for libpng-allocated data, the application must use
+png_free() to free it, and when the user transfers responsibility to libpng
+for data that the user has allocated, the user must have used png_malloc()
+or png_calloc() to allocate it.
+
+If you allocated your row_pointers in a single block, as suggested above in
+the description of the high level read interface, you must not transfer
+responsibility for freeing it to the png_set_rows or png_read_destroy function,
+because they would also try to free the individual row_pointers[i].
+
+If you allocated text_ptr.text, text_ptr.lang, and text_ptr.translated_keyword
+separately, do not transfer responsibility for freeing text_ptr to libpng,
+because when libpng fills a png_text structure it combines these members with
+the key member, and png_free_data() will free only text_ptr.key. Similarly,
+if you transfer responsibility for free'ing text_ptr from libpng to your
+application, your application must not separately free those members.
+
+The png_free_data() function will turn off the "valid" flag for anything
+it frees. If you need to turn the flag off for a chunk that was freed by
+your application instead of by libpng, you can use
+
+ png_set_invalid(png_ptr, info_ptr, mask);
+
+ mask - identifies the chunks to be made invalid,
+ containing the bitwise OR of one or
+ more of
+ PNG_INFO_gAMA, PNG_INFO_sBIT,
+ PNG_INFO_cHRM, PNG_INFO_PLTE,
+ PNG_INFO_tRNS, PNG_INFO_bKGD,
+ PNG_INFO_hIST, PNG_INFO_pHYs,
+ PNG_INFO_oFFs, PNG_INFO_tIME,
+ PNG_INFO_pCAL, PNG_INFO_sRGB,
+ PNG_INFO_iCCP, PNG_INFO_sPLT,
+ PNG_INFO_sCAL, PNG_INFO_IDAT
+
+For a more compact example of reading a PNG image, see the file example.c.
+
+Reading PNG files progressively
+
+The progressive reader is slightly different from the non-progressive
+reader. Instead of calling png_read_info(), png_read_rows(), and
+png_read_end(), you make one call to png_process_data(), which calls
+callbacks when it has the info, a row, or the end of the image. You
+set up these callbacks with png_set_progressive_read_fn(). You don't
+have to worry about the input/output functions of libpng, as you are
+giving the library the data directly in png_process_data(). I will
+assume that you have read the section on reading PNG files above,
+so I will only highlight the differences (although I will show
+all of the code).
+
+png_structp png_ptr;
+png_infop info_ptr;
+
+ /* An example code fragment of how you would
+ initialize the progressive reader in your
+ application. */
+ int
+ initialize_png_reader()
+ {
+ png_ptr = png_create_read_struct
+ (PNG_LIBPNG_VER_STRING, (png_voidp)user_error_ptr,
+ user_error_fn, user_warning_fn);
+
+ if (!png_ptr)
+ return (ERROR);
+
+ info_ptr = png_create_info_struct(png_ptr);
+
+ if (!info_ptr)
+ {
+ png_destroy_read_struct(&png_ptr,
+ (png_infopp)NULL, (png_infopp)NULL);
+ return (ERROR);
+ }
+
+ if (setjmp(png_jmpbuf(png_ptr)))
+ {
+ png_destroy_read_struct(&png_ptr, &info_ptr,
+ (png_infopp)NULL);
+ return (ERROR);
+ }
+
+ /* This one's new. You can provide functions
+ to be called when the header info is valid,
+ when each row is completed, and when the image
+ is finished. If you aren't using all functions,
+ you can specify NULL parameters. Even when all
+ three functions are NULL, you need to call
+ png_set_progressive_read_fn(). You can use
+ any struct as the user_ptr (cast to a void pointer
+ for the function call), and retrieve the pointer
+ from inside the callbacks using the function
+
+ png_get_progressive_ptr(png_ptr);
+
+ which will return a void pointer, which you have
+ to cast appropriately.
+ */
+ png_set_progressive_read_fn(png_ptr, (void *)user_ptr,
+ info_callback, row_callback, end_callback);
+
+ return 0;
+ }
+
+ /* A code fragment that you call as you receive blocks
+ of data */
+ int
+ process_data(png_bytep buffer, png_uint_32 length)
+ {
+ if (setjmp(png_jmpbuf(png_ptr)))
+ {
+ png_destroy_read_struct(&png_ptr, &info_ptr,
+ (png_infopp)NULL);
+ return (ERROR);
+ }
+
+ /* This one's new also. Simply give it a chunk
+ of data from the file stream (in order, of
+ course). On machines with segmented memory
+ models machines, don't give it any more than
+ 64K. The library seems to run fine with sizes
+ of 4K. Although you can give it much less if
+ necessary (I assume you can give it chunks of
+ 1 byte, I haven't tried less than 256 bytes
+ yet). When this function returns, you may
+ want to display any rows that were generated
+ in the row callback if you don't already do
+ so there.
+ */
+ png_process_data(png_ptr, info_ptr, buffer, length);
+
+ /* At this point you can call png_process_data_skip if
+ you want to handle data the library will skip yourself;
+ it simply returns the number of bytes to skip (and stops
+ libpng skipping that number of bytes on the next
+ png_process_data call).
+ return 0;
+ }
+
+ /* This function is called (as set by
+ png_set_progressive_read_fn() above) when enough data
+ has been supplied so all of the header has been
+ read.
+ */
+ void
+ info_callback(png_structp png_ptr, png_infop info)
+ {
+ /* Do any setup here, including setting any of
+ the transformations mentioned in the Reading
+ PNG files section. For now, you _must_ call
+ either png_start_read_image() or
+ png_read_update_info() after all the
+ transformations are set (even if you don't set
+ any). You may start getting rows before
+ png_process_data() returns, so this is your
+ last chance to prepare for that.
+
+ This is where you turn on interlace handling,
+ assuming you don't want to do it yourself.
+
+ If you need to you can stop the processing of
+ your original input data at this point by calling
+ png_process_data_pause. This returns the number
+ of unprocessed bytes from the last png_process_data
+ call - it is up to you to ensure that the next call
+ sees these bytes again. If you don't want to bother
+ with this you can get libpng to cache the unread
+ bytes by setting the 'save' parameter (see png.h) but
+ then libpng will have to copy the data internally.
+ */
+ }
+
+ /* This function is called when each row of image
+ data is complete */
+ void
+ row_callback(png_structp png_ptr, png_bytep new_row,
+ png_uint_32 row_num, int pass)
+ {
+ /* If the image is interlaced, and you turned
+ on the interlace handler, this function will
+ be called for every row in every pass. Some
+ of these rows will not be changed from the
+ previous pass. When the row is not changed,
+ the new_row variable will be NULL. The rows
+ and passes are called in order, so you don't
+ really need the row_num and pass, but I'm
+ supplying them because it may make your life
+ easier.
+
+ If you did not turn on interlace handling then
+ the callback is called for each row of each
+ sub-image when the image is interlaced. In this
+ case 'row_num' is the row in the sub-image, not
+ the row in the output image as it is in all other
+ cases.
+
+ For the non-NULL rows of interlaced images when
+ you have switched on libpng interlace handling,
+ you must call png_progressive_combine_row()
+ passing in the row and the old row. You can
+ call this function for NULL rows (it will just
+ return) and for non-interlaced images (it just
+ does the memcpy for you) if it will make the
+ code easier. Thus, you can just do this for
+ all cases if you switch on interlace handling;
+ */
+
+ png_progressive_combine_row(png_ptr, old_row,
+ new_row);
+
+ /* where old_row is what was displayed
+ previously for the row. Note that the first
+ pass (pass == 0, really) will completely cover
+ the old row, so the rows do not have to be
+ initialized. After the first pass (and only
+ for interlaced images), you will have to pass
+ the current row, and the function will combine
+ the old row and the new row.
+
+ You can also call png_process_data_pause in this
+ callback - see above.
+ */
+ }
+
+ void
+ end_callback(png_structp png_ptr, png_infop info)
+ {
+ /* This function is called after the whole image
+ has been read, including any chunks after the
+ image (up to and including the IEND). You
+ will usually have the same info chunk as you
+ had in the header, although some data may have
+ been added to the comments and time fields.
+
+ Most people won't do much here, perhaps setting
+ a flag that marks the image as finished.
+ */
+ }
+
+
+
+IV. Writing
+
+Much of this is very similar to reading. However, everything of
+importance is repeated here, so you won't have to constantly look
+back up in the reading section to understand writing.
+
+Setup
+
+You will want to do the I/O initialization before you get into libpng,
+so if it doesn't work, you don't have anything to undo. If you are not
+using the standard I/O functions, you will need to replace them with
+custom writing functions. See the discussion under Customizing libpng.
+
+ FILE *fp = fopen(file_name, "wb");
+
+ if (!fp)
+ return (ERROR);
+
+Next, png_struct and png_info need to be allocated and initialized.
+As these can be both relatively large, you may not want to store these
+on the stack, unless you have stack space to spare. Of course, you
+will want to check if they return NULL. If you are also reading,
+you won't want to name your read structure and your write structure
+both "png_ptr"; you can call them anything you like, such as
+"read_ptr" and "write_ptr". Look at pngtest.c, for example.
+
+ png_structp png_ptr = png_create_write_struct
+ (PNG_LIBPNG_VER_STRING, (png_voidp)user_error_ptr,
+ user_error_fn, user_warning_fn);
+
+ if (!png_ptr)
+ return (ERROR);
+
+ png_infop info_ptr = png_create_info_struct(png_ptr);
+ if (!info_ptr)
+ {
+ png_destroy_write_struct(&png_ptr,
+ (png_infopp)NULL);
+ return (ERROR);
+ }
+
+If you want to use your own memory allocation routines,
+define PNG_USER_MEM_SUPPORTED and use
+png_create_write_struct_2() instead of png_create_write_struct():
+
+ png_structp png_ptr = png_create_write_struct_2
+ (PNG_LIBPNG_VER_STRING, (png_voidp)user_error_ptr,
+ user_error_fn, user_warning_fn, (png_voidp)
+ user_mem_ptr, user_malloc_fn, user_free_fn);
+
+After you have these structures, you will need to set up the
+error handling. When libpng encounters an error, it expects to
+longjmp() back to your routine. Therefore, you will need to call
+setjmp() and pass the png_jmpbuf(png_ptr). If you
+write the file from different routines, you will need to update
+the png_jmpbuf(png_ptr) every time you enter a new routine that will
+call a png_*() function. See your documentation of setjmp/longjmp
+for your compiler for more information on setjmp/longjmp. See
+the discussion on libpng error handling in the Customizing Libpng
+section below for more information on the libpng error handling.
+
+ if (setjmp(png_jmpbuf(png_ptr)))
+ {
+ png_destroy_write_struct(&png_ptr, &info_ptr);
+ fclose(fp);
+ return (ERROR);
+ }
+ ...
+ return;
+
+If you would rather avoid the complexity of setjmp/longjmp issues,
+you can compile libpng with PNG_NO_SETJMP, in which case
+errors will result in a call to PNG_ABORT() which defaults to abort().
+
+You can #define PNG_ABORT() to a function that does something
+more useful than abort(), as long as your function does not
+return.
+
+Checking for invalid palette index on write was added at libpng
+1.5.10. If a pixel contains an invalid (out-of-range) index libpng issues
+a benign error. This is enabled by default because this condition is an
+error according to the PNG specification, Clause 11.3.2, but the error can
+be ignored in each png_ptr with
+
+ png_set_check_for_invalid_index(png_ptr, 0);
+
+If the error is ignored, or if png_benign_error() treats it as a warning,
+any invalid pixels are written as-is by the encoder, resulting in an
+invalid PNG datastream as output. In this case the application is
+responsible for ensuring that the pixel indexes are in range when it writes
+a PLTE chunk with fewer entries than the bit depth would allow.
+
+Now you need to set up the output code. The default for libpng is to
+use the C function fwrite(). If you use this, you will need to pass a
+valid FILE * in the function png_init_io(). Be sure that the file is
+opened in binary mode. Again, if you wish to handle writing data in
+another way, see the discussion on libpng I/O handling in the Customizing
+Libpng section below.
+
+ png_init_io(png_ptr, fp);
+
+If you are embedding your PNG into a datastream such as MNG, and don't
+want libpng to write the 8-byte signature, or if you have already
+written the signature in your application, use
+
+ png_set_sig_bytes(png_ptr, 8);
+
+to inform libpng that it should not write a signature.
+
+Write callbacks
+
+At this point, you can set up a callback function that will be
+called after each row has been written, which you can use to control
+a progress meter or the like. It's demonstrated in pngtest.c.
+You must supply a function
+
+ void write_row_callback(png_structp png_ptr, png_uint_32 row,
+ int pass);
+ {
+ /* put your code here */
+ }
+
+(You can give it another name that you like instead of "write_row_callback")
+
+To inform libpng about your function, use
+
+ png_set_write_status_fn(png_ptr, write_row_callback);
+
+When this function is called the row has already been completely processed and
+it has also been written out. The 'row' and 'pass' refer to the next row to be
+handled. For the
+non-interlaced case the row that was just handled is simply one less than the
+passed in row number, and pass will always be 0. For the interlaced case the
+same applies unless the row value is 0, in which case the row just handled was
+the last one from one of the preceding passes. Because interlacing may skip a
+pass you cannot be sure that the preceding pass is just 'pass-1', if you really
+need to know what the last pass is record (row,pass) from the callback and use
+the last recorded value each time.
+
+As with the user transform you can find the output row using the
+PNG_ROW_FROM_PASS_ROW macro.
+
+You now have the option of modifying how the compression library will
+run. The following functions are mainly for testing, but may be useful
+in some cases, like if you need to write PNG files extremely fast and
+are willing to give up some compression, or if you want to get the
+maximum possible compression at the expense of slower writing. If you
+have no special needs in this area, let the library do what it wants by
+not calling this function at all, as it has been tuned to deliver a good
+speed/compression ratio. The second parameter to png_set_filter() is
+the filter method, for which the only valid values are 0 (as of the
+July 1999 PNG specification, version 1.2) or 64 (if you are writing
+a PNG datastream that is to be embedded in a MNG datastream). The third
+parameter is a flag that indicates which filter type(s) are to be tested
+for each scanline. See the PNG specification for details on the specific
+filter types.
+
+
+ /* turn on or off filtering, and/or choose
+ specific filters. You can use either a single
+ PNG_FILTER_VALUE_NAME or the bitwise OR of one
+ or more PNG_FILTER_NAME masks.
+ */
+ png_set_filter(png_ptr, 0,
+ PNG_FILTER_NONE | PNG_FILTER_VALUE_NONE |
+ PNG_FILTER_SUB | PNG_FILTER_VALUE_SUB |
+ PNG_FILTER_UP | PNG_FILTER_VALUE_UP |
+ PNG_FILTER_AVG | PNG_FILTER_VALUE_AVG |
+ PNG_FILTER_PAETH | PNG_FILTER_VALUE_PAETH|
+ PNG_ALL_FILTERS);
+
+If an application wants to start and stop using particular filters during
+compression, it should start out with all of the filters (to ensure that
+the previous row of pixels will be stored in case it's needed later),
+and then add and remove them after the start of compression.
+
+If you are writing a PNG datastream that is to be embedded in a MNG
+datastream, the second parameter can be either 0 or 64.
+
+The png_set_compression_*() functions interface to the zlib compression
+library, and should mostly be ignored unless you really know what you are
+doing. The only generally useful call is png_set_compression_level()
+which changes how much time zlib spends on trying to compress the image
+data. See the Compression Library (zlib.h and algorithm.txt, distributed
+with zlib) for details on the compression levels.
+
+ #include zlib.h
+
+ /* Set the zlib compression level */
+ png_set_compression_level(png_ptr,
+ Z_BEST_COMPRESSION);
+
+ /* Set other zlib parameters for compressing IDAT */
+ png_set_compression_mem_level(png_ptr, 8);
+ png_set_compression_strategy(png_ptr,
+ Z_DEFAULT_STRATEGY);
+ png_set_compression_window_bits(png_ptr, 15);
+ png_set_compression_method(png_ptr, 8);
+ png_set_compression_buffer_size(png_ptr, 8192)
+
+ /* Set zlib parameters for text compression
+ * If you don't call these, the parameters
+ * fall back on those defined for IDAT chunks
+ */
+ png_set_text_compression_mem_level(png_ptr, 8);
+ png_set_text_compression_strategy(png_ptr,
+ Z_DEFAULT_STRATEGY);
+ png_set_text_compression_window_bits(png_ptr, 15);
+ png_set_text_compression_method(png_ptr, 8);
+
+Setting the contents of info for output
+
+You now need to fill in the png_info structure with all the data you
+wish to write before the actual image. Note that the only thing you
+are allowed to write after the image is the text chunks and the time
+chunk (as of PNG Specification 1.2, anyway). See png_write_end() and
+the latest PNG specification for more information on that. If you
+wish to write them before the image, fill them in now, and flag that
+data as being valid. If you want to wait until after the data, don't
+fill them until png_write_end(). For all the fields in png_info and
+their data types, see png.h. For explanations of what the fields
+contain, see the PNG specification.
+
+Some of the more important parts of the png_info are:
+
+ png_set_IHDR(png_ptr, info_ptr, width, height,
+ bit_depth, color_type, interlace_type,
+ compression_type, filter_method)
+
+ width - holds the width of the image
+ in pixels (up to 2^31).
+
+ height - holds the height of the image
+ in pixels (up to 2^31).
+
+ bit_depth - holds the bit depth of one of the
+ image channels.
+ (valid values are 1, 2, 4, 8, 16
+ and depend also on the
+ color_type. See also significant
+ bits (sBIT) below).
+
+ color_type - describes which color/alpha
+ channels are present.
+ PNG_COLOR_TYPE_GRAY
+ (bit depths 1, 2, 4, 8, 16)
+ PNG_COLOR_TYPE_GRAY_ALPHA
+ (bit depths 8, 16)
+ PNG_COLOR_TYPE_PALETTE
+ (bit depths 1, 2, 4, 8)
+ PNG_COLOR_TYPE_RGB
+ (bit_depths 8, 16)
+ PNG_COLOR_TYPE_RGB_ALPHA
+ (bit_depths 8, 16)
+
+ PNG_COLOR_MASK_PALETTE
+ PNG_COLOR_MASK_COLOR
+ PNG_COLOR_MASK_ALPHA
+
+ interlace_type - PNG_INTERLACE_NONE or
+ PNG_INTERLACE_ADAM7
+
+ compression_type - (must be
+ PNG_COMPRESSION_TYPE_DEFAULT)
+
+ filter_method - (must be PNG_FILTER_TYPE_DEFAULT
+ or, if you are writing a PNG to
+ be embedded in a MNG datastream,
+ can also be
+ PNG_INTRAPIXEL_DIFFERENCING)
+
+If you call png_set_IHDR(), the call must appear before any of the
+other png_set_*() functions, because they might require access to some of
+the IHDR settings. The remaining png_set_*() functions can be called
+in any order.
+
+If you wish, you can reset the compression_type, interlace_type, or
+filter_method later by calling png_set_IHDR() again; if you do this, the
+width, height, bit_depth, and color_type must be the same in each call.
+
+ png_set_PLTE(png_ptr, info_ptr, palette,
+ num_palette);
+
+ palette - the palette for the file
+ (array of png_color)
+ num_palette - number of entries in the palette
+
+ png_set_gAMA(png_ptr, info_ptr, file_gamma);
+ png_set_gAMA_fixed(png_ptr, info_ptr, int_file_gamma);
+
+ file_gamma - the gamma at which the image was
+ created (PNG_INFO_gAMA)
+
+ int_file_gamma - 100,000 times the gamma at which
+ the image was created
+
+ png_set_cHRM(png_ptr, info_ptr, white_x, white_y, red_x, red_y,
+ green_x, green_y, blue_x, blue_y)
+ png_set_cHRM_XYZ(png_ptr, info_ptr, red_X, red_Y, red_Z, green_X,
+ green_Y, green_Z, blue_X, blue_Y, blue_Z)
+ png_set_cHRM_fixed(png_ptr, info_ptr, int_white_x, int_white_y,
+ int_red_x, int_red_y, int_green_x, int_green_y,
+ int_blue_x, int_blue_y)
+ png_set_cHRM_XYZ_fixed(png_ptr, info_ptr, int_red_X, int_red_Y,
+ int_red_Z, int_green_X, int_green_Y, int_green_Z,
+ int_blue_X, int_blue_Y, int_blue_Z)
+
+ {white,red,green,blue}_{x,y}
+ A color space encoding specified using the chromaticities
+ of the end points and the white point.
+
+ {red,green,blue}_{X,Y,Z}
+ A color space encoding specified using the encoding end
+ points - the CIE tristimulus specification of the intended
+ color of the red, green and blue channels in the PNG RGB
+ data. The white point is simply the sum of the three end
+ points.
+
+ png_set_sRGB(png_ptr, info_ptr, srgb_intent);
+
+ srgb_intent - the rendering intent
+ (PNG_INFO_sRGB) The presence of
+ the sRGB chunk means that the pixel
+ data is in the sRGB color space.
+ This chunk also implies specific
+ values of gAMA and cHRM. Rendering
+ intent is the CSS-1 property that
+ has been defined by the International
+ Color Consortium
+ (http://www.color.org).
+ It can be one of
+ PNG_sRGB_INTENT_SATURATION,
+ PNG_sRGB_INTENT_PERCEPTUAL,
+ PNG_sRGB_INTENT_ABSOLUTE, or
+ PNG_sRGB_INTENT_RELATIVE.
+
+
+ png_set_sRGB_gAMA_and_cHRM(png_ptr, info_ptr,
+ srgb_intent);
+
+ srgb_intent - the rendering intent
+ (PNG_INFO_sRGB) The presence of the
+ sRGB chunk means that the pixel
+ data is in the sRGB color space.
+ This function also causes gAMA and
+ cHRM chunks with the specific values
+ that are consistent with sRGB to be
+ written.
+
+ png_set_iCCP(png_ptr, info_ptr, name, compression_type,
+ profile, proflen);
+
+ name - The profile name.
+
+ compression_type - The compression type; always
+ PNG_COMPRESSION_TYPE_BASE for PNG 1.0.
+ You may give NULL to this argument to
+ ignore it.
+
+ profile - International Color Consortium color
+ profile data. May contain NULs.
+
+ proflen - length of profile data in bytes.
+
+ png_set_sBIT(png_ptr, info_ptr, sig_bit);
+
+ sig_bit - the number of significant bits for
+ (PNG_INFO_sBIT) each of the gray, red,
+ green, and blue channels, whichever are
+ appropriate for the given color type
+ (png_color_16)
+
+ png_set_tRNS(png_ptr, info_ptr, trans_alpha,
+ num_trans, trans_color);
+
+ trans_alpha - array of alpha (transparency)
+ entries for palette (PNG_INFO_tRNS)
+
+ num_trans - number of transparent entries
+ (PNG_INFO_tRNS)
+
+ trans_color - graylevel or color sample values
+ (in order red, green, blue) of the
+ single transparent color for
+ non-paletted images (PNG_INFO_tRNS)
+
+ png_set_hIST(png_ptr, info_ptr, hist);
+
+ hist - histogram of palette (array of
+ png_uint_16) (PNG_INFO_hIST)
+
+ png_set_tIME(png_ptr, info_ptr, mod_time);
+
+ mod_time - time image was last modified
+ (PNG_VALID_tIME)
+
+ png_set_bKGD(png_ptr, info_ptr, background);
+
+ background - background color (of type
+ png_color_16p) (PNG_VALID_bKGD)
+
+ png_set_text(png_ptr, info_ptr, text_ptr, num_text);
+
+ text_ptr - array of png_text holding image
+ comments
+
+ text_ptr[i].compression - type of compression used
+ on "text" PNG_TEXT_COMPRESSION_NONE
+ PNG_TEXT_COMPRESSION_zTXt
+ PNG_ITXT_COMPRESSION_NONE
+ PNG_ITXT_COMPRESSION_zTXt
+ text_ptr[i].key - keyword for comment. Must contain
+ 1-79 characters.
+ text_ptr[i].text - text comments for current
+ keyword. Can be NULL or empty.
+ text_ptr[i].text_length - length of text string,
+ after decompression, 0 for iTXt
+ text_ptr[i].itxt_length - length of itxt string,
+ after decompression, 0 for tEXt/zTXt
+ text_ptr[i].lang - language of comment (NULL or
+ empty for unknown).
+ text_ptr[i].translated_keyword - keyword in UTF-8 (NULL
+ or empty for unknown).
+
+ Note that the itxt_length, lang, and lang_key
+ members of the text_ptr structure only exist when the
+ library is built with iTXt chunk support. Prior to
+ libpng-1.4.0 the library was built by default without
+ iTXt support. Also note that when iTXt is supported,
+ they contain NULL pointers when the "compression"
+ field contains PNG_TEXT_COMPRESSION_NONE or
+ PNG_TEXT_COMPRESSION_zTXt.
+
+ num_text - number of comments
+
+ png_set_sPLT(png_ptr, info_ptr, &palette_ptr,
+ num_spalettes);
+
+ palette_ptr - array of png_sPLT_struct structures
+ to be added to the list of palettes
+ in the info structure.
+ num_spalettes - number of palette structures to be
+ added.
+
+ png_set_oFFs(png_ptr, info_ptr, offset_x, offset_y,
+ unit_type);
+
+ offset_x - positive offset from the left
+ edge of the screen
+
+ offset_y - positive offset from the top
+ edge of the screen
+
+ unit_type - PNG_OFFSET_PIXEL, PNG_OFFSET_MICROMETER
+
+ png_set_pHYs(png_ptr, info_ptr, res_x, res_y,
+ unit_type);
+
+ res_x - pixels/unit physical resolution
+ in x direction
+
+ res_y - pixels/unit physical resolution
+ in y direction
+
+ unit_type - PNG_RESOLUTION_UNKNOWN,
+ PNG_RESOLUTION_METER
+
+ png_set_sCAL(png_ptr, info_ptr, unit, width, height)
+
+ unit - physical scale units (an integer)
+
+ width - width of a pixel in physical scale units
+
+ height - height of a pixel in physical scale units
+ (width and height are doubles)
+
+ png_set_sCAL_s(png_ptr, info_ptr, unit, width, height)
+
+ unit - physical scale units (an integer)
+
+ width - width of a pixel in physical scale units
+ expressed as a string
+
+ height - height of a pixel in physical scale units
+ (width and height are strings like "2.54")
+
+ png_set_unknown_chunks(png_ptr, info_ptr, &unknowns,
+ num_unknowns)
+
+ unknowns - array of png_unknown_chunk
+ structures holding unknown chunks
+ unknowns[i].name - name of unknown chunk
+ unknowns[i].data - data of unknown chunk
+ unknowns[i].size - size of unknown chunk's data
+ unknowns[i].location - position to write chunk in file
+ 0: do not write chunk
+ PNG_HAVE_IHDR: before PLTE
+ PNG_HAVE_PLTE: before IDAT
+ PNG_AFTER_IDAT: after IDAT
+
+The "location" member is set automatically according to
+what part of the output file has already been written.
+You can change its value after calling png_set_unknown_chunks()
+as demonstrated in pngtest.c. Within each of the "locations",
+the chunks are sequenced according to their position in the
+structure (that is, the value of "i", which is the order in which
+the chunk was either read from the input file or defined with
+png_set_unknown_chunks).
+
+A quick word about text and num_text. text is an array of png_text
+structures. num_text is the number of valid structures in the array.
+Each png_text structure holds a language code, a keyword, a text value,
+and a compression type.
+
+The compression types have the same valid numbers as the compression
+types of the image data. Currently, the only valid number is zero.
+However, you can store text either compressed or uncompressed, unlike
+images, which always have to be compressed. So if you don't want the
+text compressed, set the compression type to PNG_TEXT_COMPRESSION_NONE.
+Because tEXt and zTXt chunks don't have a language field, if you
+specify PNG_TEXT_COMPRESSION_NONE or PNG_TEXT_COMPRESSION_zTXt
+any language code or translated keyword will not be written out.
+
+Until text gets around a few hundred bytes, it is not worth compressing it.
+After the text has been written out to the file, the compression type
+is set to PNG_TEXT_COMPRESSION_NONE_WR or PNG_TEXT_COMPRESSION_zTXt_WR,
+so that it isn't written out again at the end (in case you are calling
+png_write_end() with the same struct).
+
+The keywords that are given in the PNG Specification are:
+
+ Title Short (one line) title or
+ caption for image
+
+ Author Name of image's creator
+
+ Description Description of image (possibly long)
+
+ Copyright Copyright notice
+
+ Creation Time Time of original image creation
+ (usually RFC 1123 format, see below)
+
+ Software Software used to create the image
+
+ Disclaimer Legal disclaimer
+
+ Warning Warning of nature of content
+
+ Source Device used to create the image
+
+ Comment Miscellaneous comment; conversion
+ from other image format
+
+The keyword-text pairs work like this. Keywords should be short
+simple descriptions of what the comment is about. Some typical
+keywords are found in the PNG specification, as is some recommendations
+on keywords. You can repeat keywords in a file. You can even write
+some text before the image and some after. For example, you may want
+to put a description of the image before the image, but leave the
+disclaimer until after, so viewers working over modem connections
+don't have to wait for the disclaimer to go over the modem before
+they start seeing the image. Finally, keywords should be full
+words, not abbreviations. Keywords and text are in the ISO 8859-1
+(Latin-1) character set (a superset of regular ASCII) and can not
+contain NUL characters, and should not contain control or other
+unprintable characters. To make the comments widely readable, stick
+with basic ASCII, and avoid machine specific character set extensions
+like the IBM-PC character set. The keyword must be present, but
+you can leave off the text string on non-compressed pairs.
+Compressed pairs must have a text string, as only the text string
+is compressed anyway, so the compression would be meaningless.
+
+PNG supports modification time via the png_time structure. Two
+conversion routines are provided, png_convert_from_time_t() for
+time_t and png_convert_from_struct_tm() for struct tm. The
+time_t routine uses gmtime(). You don't have to use either of
+these, but if you wish to fill in the png_time structure directly,
+you should provide the time in universal time (GMT) if possible
+instead of your local time. Note that the year number is the full
+year (e.g. 1998, rather than 98 - PNG is year 2000 compliant!), and
+that months start with 1.
+
+If you want to store the time of the original image creation, you should
+use a plain tEXt chunk with the "Creation Time" keyword. This is
+necessary because the "creation time" of a PNG image is somewhat vague,
+depending on whether you mean the PNG file, the time the image was
+created in a non-PNG format, a still photo from which the image was
+scanned, or possibly the subject matter itself. In order to facilitate
+machine-readable dates, it is recommended that the "Creation Time"
+tEXt chunk use RFC 1123 format dates (e.g. "22 May 1997 18:07:10 GMT"),
+although this isn't a requirement. Unlike the tIME chunk, the
+"Creation Time" tEXt chunk is not expected to be automatically changed
+by the software. To facilitate the use of RFC 1123 dates, a function
+png_convert_to_rfc1123_buffer(buffer, png_timep) is provided to
+convert from PNG time to an RFC 1123 format string. The caller must provide
+a writeable buffer of at least 29 bytes.
+
+Writing unknown chunks
+
+You can use the png_set_unknown_chunks function to queue up private chunks
+for writing. You give it a chunk name, location, raw data, and a size. You
+also must use png_set_keep_unknown_chunks() to ensure that libpng will
+handle them. That's all there is to it. The chunks will be written by the
+next following png_write_info_before_PLTE, png_write_info, or png_write_end
+function, depending upon the specified location. Any chunks previously
+read into the info structure's unknown-chunk list will also be written out
+in a sequence that satisfies the PNG specification's ordering rules.
+
+Here is an example of writing two private chunks, prVt and miNE:
+
+ #ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED
+ /* Set unknown chunk data */
+ png_unknown_chunk unk_chunk[2];
+ strcpy((char *) unk_chunk[0].name, "prVt";
+ unk_chunk[0].data = (unsigned char *) "PRIVATE DATA";
+ unk_chunk[0].size = strlen(unk_chunk[0].data)+1;
+ unk_chunk[0].location = PNG_HAVE_IHDR;
+ strcpy((char *) unk_chunk[1].name, "miNE";
+ unk_chunk[1].data = (unsigned char *) "MY CHUNK DATA";
+ unk_chunk[1].size = strlen(unk_chunk[0].data)+1;
+ unk_chunk[1].location = PNG_AFTER_IDAT;
+ png_set_unknown_chunks(write_ptr, write_info_ptr,
+ unk_chunk, 2);
+ /* Needed because miNE is not safe-to-copy */
+ png_set_keep_unknown_chunks(png, PNG_HANDLE_CHUNK_ALWAYS,
+ (png_bytep) "miNE", 1);
+ # if PNG_LIBPNG_VER < 10600
+ /* Deal with unknown chunk location bug in 1.5.x and earlier */
+ png_set_unknown_chunk_location(png, info, 0, PNG_HAVE_IHDR);
+ png_set_unknown_chunk_location(png, info, 1, PNG_AFTER_IDAT);
+ # endif
+ # if PNG_LIBPNG_VER < 10500
+ /* PNG_AFTER_IDAT writes two copies of the chunk prior to libpng-1.5.0,
+ * one before IDAT and another after IDAT, so don't use it; only use
+ * PNG_HAVE_IHDR location. This call resets the location previously
+ * set by assignment and png_set_unknown_chunk_location() for chunk 1.
+ */
+ png_set_unknown_chunk_location(png, info, 1, PNG_HAVE_IHDR);
+ # endif
+ #endif
+
+The high-level write interface
+
+At this point there are two ways to proceed; through the high-level
+write interface, or through a sequence of low-level write operations.
+You can use the high-level interface if your image data is present
+in the info structure. All defined output
+transformations are permitted, enabled by the following masks.
+
+ PNG_TRANSFORM_IDENTITY No transformation
+ PNG_TRANSFORM_PACKING Pack 1, 2 and 4-bit samples
+ PNG_TRANSFORM_PACKSWAP Change order of packed
+ pixels to LSB first
+ PNG_TRANSFORM_INVERT_MONO Invert monochrome images
+ PNG_TRANSFORM_SHIFT Normalize pixels to the
+ sBIT depth
+ PNG_TRANSFORM_BGR Flip RGB to BGR, RGBA
+ to BGRA
+ PNG_TRANSFORM_SWAP_ALPHA Flip RGBA to ARGB or GA
+ to AG
+ PNG_TRANSFORM_INVERT_ALPHA Change alpha from opacity
+ to transparency
+ PNG_TRANSFORM_SWAP_ENDIAN Byte-swap 16-bit samples
+ PNG_TRANSFORM_STRIP_FILLER Strip out filler
+ bytes (deprecated).
+ PNG_TRANSFORM_STRIP_FILLER_BEFORE Strip out leading
+ filler bytes
+ PNG_TRANSFORM_STRIP_FILLER_AFTER Strip out trailing
+ filler bytes
+
+If you have valid image data in the info structure (you can use
+png_set_rows() to put image data in the info structure), simply do this:
+
+ png_write_png(png_ptr, info_ptr, png_transforms, NULL)
+
+where png_transforms is an integer containing the bitwise OR of some set of
+transformation flags. This call is equivalent to png_write_info(),
+followed the set of transformations indicated by the transform mask,
+then png_write_image(), and finally png_write_end().
+
+(The final parameter of this call is not yet used. Someday it might point
+to transformation parameters required by some future output transform.)
+
+You must use png_transforms and not call any png_set_transform() functions
+when you use png_write_png().
+
+The low-level write interface
+
+If you are going the low-level route instead, you are now ready to
+write all the file information up to the actual image data. You do
+this with a call to png_write_info().
+
+ png_write_info(png_ptr, info_ptr);
+
+Note that there is one transformation you may need to do before
+png_write_info(). In PNG files, the alpha channel in an image is the
+level of opacity. If your data is supplied as a level of transparency,
+you can invert the alpha channel before you write it, so that 0 is
+fully transparent and 255 (in 8-bit or paletted images) or 65535
+(in 16-bit images) is fully opaque, with
+
+ png_set_invert_alpha(png_ptr);
+
+This must appear before png_write_info() instead of later with the
+other transformations because in the case of paletted images the tRNS
+chunk data has to be inverted before the tRNS chunk is written. If
+your image is not a paletted image, the tRNS data (which in such cases
+represents a single color to be rendered as transparent) won't need to
+be changed, and you can safely do this transformation after your
+png_write_info() call.
+
+If you need to write a private chunk that you want to appear before
+the PLTE chunk when PLTE is present, you can write the PNG info in
+two steps, and insert code to write your own chunk between them:
+
+ png_write_info_before_PLTE(png_ptr, info_ptr);
+ png_set_unknown_chunks(png_ptr, info_ptr, ...);
+ png_write_info(png_ptr, info_ptr);
+
+After you've written the file information, you can set up the library
+to handle any special transformations of the image data. The various
+ways to transform the data will be described in the order that they
+should occur. This is important, as some of these change the color
+type and/or bit depth of the data, and some others only work on
+certain color types and bit depths. Even though each transformation
+checks to see if it has data that it can do something with, you should
+make sure to only enable a transformation if it will be valid for the
+data. For example, don't swap red and blue on grayscale data.
+
+PNG files store RGB pixels packed into 3 or 6 bytes. This code tells
+the library to strip input data that has 4 or 8 bytes per pixel down
+to 3 or 6 bytes (or strip 2 or 4-byte grayscale+filler data to 1 or 2
+bytes per pixel).
+
+ png_set_filler(png_ptr, 0, PNG_FILLER_BEFORE);
+
+where the 0 is unused, and the location is either PNG_FILLER_BEFORE or
+PNG_FILLER_AFTER, depending upon whether the filler byte in the pixel
+is stored XRGB or RGBX.
+
+PNG files pack pixels of bit depths 1, 2, and 4 into bytes as small as
+they can, resulting in, for example, 8 pixels per byte for 1 bit files.
+If the data is supplied at 1 pixel per byte, use this code, which will
+correctly pack the pixels into a single byte:
+
+ png_set_packing(png_ptr);
+
+PNG files reduce possible bit depths to 1, 2, 4, 8, and 16. If your
+data is of another bit depth, you can write an sBIT chunk into the
+file so that decoders can recover the original data if desired.
+
+ /* Set the true bit depth of the image data */
+ if (color_type & PNG_COLOR_MASK_COLOR)
+ {
+ sig_bit.red = true_bit_depth;
+ sig_bit.green = true_bit_depth;
+ sig_bit.blue = true_bit_depth;
+ }
+
+ else
+ {
+ sig_bit.gray = true_bit_depth;
+ }
+
+ if (color_type & PNG_COLOR_MASK_ALPHA)
+ {
+ sig_bit.alpha = true_bit_depth;
+ }
+
+ png_set_sBIT(png_ptr, info_ptr, &sig_bit);
+
+If the data is stored in the row buffer in a bit depth other than
+one supported by PNG (e.g. 3 bit data in the range 0-7 for a 4-bit PNG),
+this will scale the values to appear to be the correct bit depth as
+is required by PNG.
+
+ png_set_shift(png_ptr, &sig_bit);
+
+PNG files store 16-bit pixels in network byte order (big-endian,
+ie. most significant bits first). This code would be used if they are
+supplied the other way (little-endian, i.e. least significant bits
+first, the way PCs store them):
+
+ if (bit_depth > 8)
+ png_set_swap(png_ptr);
+
+If you are using packed-pixel images (1, 2, or 4 bits/pixel), and you
+need to change the order the pixels are packed into bytes, you can use:
+
+ if (bit_depth < 8)
+ png_set_packswap(png_ptr);
+
+PNG files store 3 color pixels in red, green, blue order. This code
+would be used if they are supplied as blue, green, red:
+
+ png_set_bgr(png_ptr);
+
+PNG files describe monochrome as black being zero and white being
+one. This code would be used if the pixels are supplied with this reversed
+(black being one and white being zero):
+
+ png_set_invert_mono(png_ptr);
+
+Finally, you can write your own transformation function if none of
+the existing ones meets your needs. This is done by setting a callback
+with
+
+ png_set_write_user_transform_fn(png_ptr,
+ write_transform_fn);
+
+You must supply the function
+
+ void write_transform_fn(png_structp png_ptr, png_row_infop
+ row_info, png_bytep data)
+
+See pngtest.c for a working example. Your function will be called
+before any of the other transformations are processed. If supported
+libpng also supplies an information routine that may be called from
+your callback:
+
+ png_get_current_row_number(png_ptr);
+ png_get_current_pass_number(png_ptr);
+
+This returns the current row passed to the transform. With interlaced
+images the value returned is the row in the input sub-image image. Use
+PNG_ROW_FROM_PASS_ROW(row, pass) and PNG_COL_FROM_PASS_COL(col, pass) to
+find the output pixel (x,y) given an interlaced sub-image pixel (row,col,pass).
+
+The discussion of interlace handling above contains more information on how to
+use these values.
+
+You can also set up a pointer to a user structure for use by your
+callback function.
+
+ png_set_user_transform_info(png_ptr, user_ptr, 0, 0);
+
+The user_channels and user_depth parameters of this function are ignored
+when writing; you can set them to zero as shown.
+
+You can retrieve the pointer via the function png_get_user_transform_ptr().
+For example:
+
+ voidp write_user_transform_ptr =
+ png_get_user_transform_ptr(png_ptr);
+
+It is possible to have libpng flush any pending output, either manually,
+or automatically after a certain number of lines have been written. To
+flush the output stream a single time call:
+
+ png_write_flush(png_ptr);
+
+and to have libpng flush the output stream periodically after a certain
+number of scanlines have been written, call:
+
+ png_set_flush(png_ptr, nrows);
+
+Note that the distance between rows is from the last time png_write_flush()
+was called, or the first row of the image if it has never been called.
+So if you write 50 lines, and then png_set_flush 25, it will flush the
+output on the next scanline, and every 25 lines thereafter, unless
+png_write_flush() is called before 25 more lines have been written.
+If nrows is too small (less than about 10 lines for a 640 pixel wide
+RGB image) the image compression may decrease noticeably (although this
+may be acceptable for real-time applications). Infrequent flushing will
+only degrade the compression performance by a few percent over images
+that do not use flushing.
+
+Writing the image data
+
+That's it for the transformations. Now you can write the image data.
+The simplest way to do this is in one function call. If you have the
+whole image in memory, you can just call png_write_image() and libpng
+will write the image. You will need to pass in an array of pointers to
+each row. This function automatically handles interlacing, so you don't
+need to call png_set_interlace_handling() or call this function multiple
+times, or any of that other stuff necessary with png_write_rows().
+
+ png_write_image(png_ptr, row_pointers);
+
+where row_pointers is:
+
+ png_byte *row_pointers[height];
+
+You can point to void or char or whatever you use for pixels.
+
+If you don't want to write the whole image at once, you can
+use png_write_rows() instead. If the file is not interlaced,
+this is simple:
+
+ png_write_rows(png_ptr, row_pointers,
+ number_of_rows);
+
+row_pointers is the same as in the png_write_image() call.
+
+If you are just writing one row at a time, you can do this with
+a single row_pointer instead of an array of row_pointers:
+
+ png_bytep row_pointer = row;
+
+ png_write_row(png_ptr, row_pointer);
+
+When the file is interlaced, things can get a good deal more complicated.
+The only currently (as of the PNG Specification version 1.2, dated July
+1999) defined interlacing scheme for PNG files is the "Adam7" interlace
+scheme, that breaks down an image into seven smaller images of varying
+size. libpng will build these images for you, or you can do them
+yourself. If you want to build them yourself, see the PNG specification
+for details of which pixels to write when.
+
+If you don't want libpng to handle the interlacing details, just
+use png_set_interlace_handling() and call png_write_rows() the
+correct number of times to write all the sub-images
+(png_set_interlace_handling() returns the number of sub-images.)
+
+If you want libpng to build the sub-images, call this before you start
+writing any rows:
+
+ number_of_passes = png_set_interlace_handling(png_ptr);
+
+This will return the number of passes needed. Currently, this is seven,
+but may change if another interlace type is added.
+
+Then write the complete image number_of_passes times.
+
+ png_write_rows(png_ptr, row_pointers, number_of_rows);
+
+Think carefully before you write an interlaced image. Typically code that
+reads such images reads all the image data into memory, uncompressed, before
+doing any processing. Only code that can display an image on the fly can
+take advantage of the interlacing and even then the image has to be exactly
+the correct size for the output device, because scaling an image requires
+adjacent pixels and these are not available until all the passes have been
+read.
+
+If you do write an interlaced image you will hardly ever need to handle
+the interlacing yourself. Call png_set_interlace_handling() and use the
+approach described above.
+
+The only time it is conceivable that you will really need to write an
+interlaced image pass-by-pass is when you have read one pass by pass and
+made some pixel-by-pixel transformation to it, as described in the read
+code above. In this case use the PNG_PASS_ROWS and PNG_PASS_COLS macros
+to determine the size of each sub-image in turn and simply write the rows
+you obtained from the read code.
+
+Finishing a sequential write
+
+After you are finished writing the image, you should finish writing
+the file. If you are interested in writing comments or time, you should
+pass an appropriately filled png_info pointer. If you are not interested,
+you can pass NULL.
+
+ png_write_end(png_ptr, info_ptr);
+
+When you are done, you can free all memory used by libpng like this:
+
+ png_destroy_write_struct(&png_ptr, &info_ptr);
+
+It is also possible to individually free the info_ptr members that
+point to libpng-allocated storage with the following function:
+
+ png_free_data(png_ptr, info_ptr, mask, seq)
+
+ mask - identifies data to be freed, a mask
+ containing the bitwise OR of one or
+ more of
+ PNG_FREE_PLTE, PNG_FREE_TRNS,
+ PNG_FREE_HIST, PNG_FREE_ICCP,
+ PNG_FREE_PCAL, PNG_FREE_ROWS,
+ PNG_FREE_SCAL, PNG_FREE_SPLT,
+ PNG_FREE_TEXT, PNG_FREE_UNKN,
+ or simply PNG_FREE_ALL
+
+ seq - sequence number of item to be freed
+ (-1 for all items)
+
+This function may be safely called when the relevant storage has
+already been freed, or has not yet been allocated, or was allocated
+by the user and not by libpng, and will in those cases do nothing.
+The "seq" parameter is ignored if only one item of the selected data
+type, such as PLTE, is allowed. If "seq" is not -1, and multiple items
+are allowed for the data type identified in the mask, such as text or
+sPLT, only the n'th item in the structure is freed, where n is "seq".
+
+If you allocated data such as a palette that you passed in to libpng
+with png_set_*, you must not free it until just before the call to
+png_destroy_write_struct().
+
+The default behavior is only to free data that was allocated internally
+by libpng. This can be changed, so that libpng will not free the data,
+or so that it will free data that was allocated by the user with png_malloc()
+or png_calloc() and passed in via a png_set_*() function, with
+
+ png_data_freer(png_ptr, info_ptr, freer, mask)
+
+ freer - one of
+ PNG_DESTROY_WILL_FREE_DATA
+ PNG_SET_WILL_FREE_DATA
+ PNG_USER_WILL_FREE_DATA
+
+ mask - which data elements are affected
+ same choices as in png_free_data()
+
+For example, to transfer responsibility for some data from a read structure
+to a write structure, you could use
+
+ png_data_freer(read_ptr, read_info_ptr,
+ PNG_USER_WILL_FREE_DATA,
+ PNG_FREE_PLTE|PNG_FREE_tRNS|PNG_FREE_hIST)
+
+ png_data_freer(write_ptr, write_info_ptr,
+ PNG_DESTROY_WILL_FREE_DATA,
+ PNG_FREE_PLTE|PNG_FREE_tRNS|PNG_FREE_hIST)
+
+thereby briefly reassigning responsibility for freeing to the user but
+immediately afterwards reassigning it once more to the write_destroy
+function. Having done this, it would then be safe to destroy the read
+structure and continue to use the PLTE, tRNS, and hIST data in the write
+structure.
+
+This function only affects data that has already been allocated.
+You can call this function before calling after the png_set_*() functions
+to control whether the user or png_destroy_*() is supposed to free the data.
+When the user assumes responsibility for libpng-allocated data, the
+application must use
+png_free() to free it, and when the user transfers responsibility to libpng
+for data that the user has allocated, the user must have used png_malloc()
+or png_calloc() to allocate it.
+
+If you allocated text_ptr.text, text_ptr.lang, and text_ptr.translated_keyword
+separately, do not transfer responsibility for freeing text_ptr to libpng,
+because when libpng fills a png_text structure it combines these members with
+the key member, and png_free_data() will free only text_ptr.key. Similarly,
+if you transfer responsibility for free'ing text_ptr from libpng to your
+application, your application must not separately free those members.
+For a more compact example of writing a PNG image, see the file example.c.
+
+V. Simplified API
+
+The simplified API, which became available in libpng-1.6.0, hides the details
+of both libpng and the PNG file format itself.
+It allows PNG files to be read into a very limited number of
+in-memory bitmap formats or to be written from the same formats. If these
+formats do not accommodate your needs then you can, and should, use the more
+sophisticated APIs above - these support a wide variety of in-memory formats
+and a wide variety of sophisticated transformations to those formats as well
+as a wide variety of APIs to manipulate ancilliary information.
+
+To read a PNG file using the simplified API:
+
+ 1) Declare a 'png_image' structure (see below) on the
+ stack and memset() it to all zero.
+
+ 2) Call the appropriate png_image_begin_read... function.
+
+ 3) Set the png_image 'format' member to the required
+ format and allocate a buffer for the image.
+
+ 4) Call png_image_finish_read to read the image into
+ your buffer.
+
+There are no restrictions on the format of the PNG input itself; all valid
+color types, bit depths, and interlace methods are acceptable, and the
+input image is transformed as necessary to the requested in-memory format
+during the png_image_finish_read() step.
+
+To write a PNG file using the simplified API:
+
+ 1) Declare a 'png_image' structure on the stack and memset()
+ it to all zero.
+
+ 2) Initialize the members of the structure that describe the
+ image, setting the 'format' member to the format of the
+ image in memory.
+
+ 3) Call the appropriate png_image_write... function with a
+ pointer to the image to write the PNG data.
+
+png_image is a structure that describes the in-memory format of an image
+when it is being read or define the in-memory format of an image that you
+need to write. The "png_image" structure contains the following members:
+
+ png_uint_32 version Set to PNG_IMAGE_VERSION
+ png_uint_32 width Image width in pixels (columns)
+ png_uint_32 height Image height in pixels (rows)
+ png_uint_32 format Image format as defined below
+ png_uint_32 flags A bit mask containing informational flags
+ png_controlp opaque Initialize to NULL, free with png_image_free
+ png_uint_32 colormap_entries; Number of entries in the color-map
+ png_uint_32 warning_or_error;
+ char message[64];
+
+In the event of an error or warning the following field warning_or_error
+field will be set to a non-zero value and the 'message' field will contain
+a '\0' terminated string with the libpng error or warning message. If both
+warnings and an error were encountered, only the error is recorded. If there
+are multiple warnings, only the first one is recorded.
+
+The upper 30 bits of this value are reserved; the low two bits contain
+a two bit code such that a value more than 1 indicates a failure in the API
+just called:
+
+ 0 - no warning or error
+ 1 - warning
+ 2 - error
+ 3 - error preceded by warning
+
+The pixels (samples) of the image have one to four channels whose components
+have original values in the range 0 to 1.0:
+
+ 1: A single gray or luminance channel (G).
+ 2: A gray/luminance channel and an alpha channel (GA).
+ 3: Three red, green, blue color channels (RGB).
+ 4: Three color channels and an alpha channel (RGBA).
+
+The channels are encoded in one of two ways:
+
+ a) As a small integer, value 0..255, contained in a single byte. For the
+alpha channel the original value is simply value/255. For the color or
+luminance channels the value is encoded according to the sRGB specification
+and matches the 8-bit format expected by typical display devices.
+
+The color/gray channels are not scaled (pre-multiplied) by the alpha
+channel and are suitable for passing to color management software.
+
+ b) As a value in the range 0..65535, contained in a 2-byte integer, in
+the native byte order of the platform on which the application is running.
+All channels can be converted to the original value by dividing by 65535; all
+channels are linear. Color channels use the RGB encoding (RGB end-points) of
+the sRGB specification. This encoding is identified by the
+PNG_FORMAT_FLAG_LINEAR flag below.
+
+When an alpha channel is present it is expected to denote pixel coverage
+of the color or luminance channels and is returned as an associated alpha
+channel: the color/gray channels are scaled (pre-multiplied) by the alpha
+value.
+
+When a color-mapped image is used as a result of calling
+png_image_read_colormap or png_image_write_colormap the channels are encoded
+in the color-map and the descriptions above apply to the color-map entries.
+The image data is encoded as small integers, value 0..255, that index the
+entries in the color-map. One integer (one byte) is stored for each pixel.
+
+PNG_FORMAT_*
+
+The #defines to be used in png_image::format. Each #define identifies a
+particular layout of channel data and, if present, alpha values. There are
+separate defines for each of the two channel encodings.
+
+A format is built up using single bit flag values. Not all combinations are
+valid: use the bit flag values below for testing a format returned by the
+read APIs, but set formats from the derived values.
+
+When reading or writing color-mapped images the format should be set to the
+format of the entries in the color-map then png_image_{read,write}_colormap
+called to read or write the color-map and set the format correctly for the
+image data. Do not set the PNG_FORMAT_FLAG_COLORMAP bit directly!
+
+NOTE: libpng can be built with particular features disabled, if you see
+compiler errors because the definition of one of the following flags has been
+compiled out it is because libpng does not have the required support. It is
+possible, however, for the libpng configuration to enable the format on just
+read or just write; in that case you may see an error at run time. You can
+guard against this by checking for the definition of:
+
+ PNG_SIMPLIFIED_{READ,WRITE}_{BGR,AFIRST}_SUPPORTED
+
+ PNG_FORMAT_FLAG_ALPHA 0x01 format with an alpha channel
+ PNG_FORMAT_FLAG_COLOR 0x02 color format: otherwise grayscale
+ PNG_FORMAT_FLAG_LINEAR 0x04 png_uint_16 channels else png_byte
+ PNG_FORMAT_FLAG_COLORMAP 0x08 libpng use only
+ PNG_FORMAT_FLAG_BGR 0x10 BGR colors, else order is RGB
+ PNG_FORMAT_FLAG_AFIRST 0x20 alpha channel comes first
+
+Supported formats are as follows. Future versions of libpng may support more
+formats; for compatibility with older versions simply check if the format
+macro is defined using #ifdef. These defines describe the in-memory layout
+of the components of the pixels of the image.
+
+First the single byte formats:
+
+ PNG_FORMAT_GRAY 0
+ PNG_FORMAT_GA PNG_FORMAT_FLAG_ALPHA
+ PNG_FORMAT_AG (PNG_FORMAT_GA|PNG_FORMAT_FLAG_AFIRST)
+ PNG_FORMAT_RGB PNG_FORMAT_FLAG_COLOR
+ PNG_FORMAT_BGR (PNG_FORMAT_FLAG_COLOR|PNG_FORMAT_FLAG_BGR)
+ PNG_FORMAT_RGBA (PNG_FORMAT_RGB|PNG_FORMAT_FLAG_ALPHA)
+ PNG_FORMAT_ARGB (PNG_FORMAT_RGBA|PNG_FORMAT_FLAG_AFIRST)
+ PNG_FORMAT_BGRA (PNG_FORMAT_BGR|PNG_FORMAT_FLAG_ALPHA)
+ PNG_FORMAT_ABGR (PNG_FORMAT_BGRA|PNG_FORMAT_FLAG_AFIRST)
+
+Then the linear 2-byte formats. When naming these "Y" is used to
+indicate a luminance (gray) channel. The component order within the pixel
+is always the same - there is no provision for swapping the order of the
+components in the linear format. The components are 16-bit integers in
+the native byte order for your platform, and there is no provision for
+swapping the bytes to a different endian condition.
+
+ PNG_FORMAT_LINEAR_Y PNG_FORMAT_FLAG_LINEAR
+ PNG_FORMAT_LINEAR_Y_ALPHA
+ (PNG_FORMAT_FLAG_LINEAR|PNG_FORMAT_FLAG_ALPHA)
+ PNG_FORMAT_LINEAR_RGB
+ (PNG_FORMAT_FLAG_LINEAR|PNG_FORMAT_FLAG_COLOR)
+ PNG_FORMAT_LINEAR_RGB_ALPHA
+ (PNG_FORMAT_FLAG_LINEAR|PNG_FORMAT_FLAG_COLOR|
+ PNG_FORMAT_FLAG_ALPHA)
+
+Color-mapped formats are obtained by calling png_image_{read,write}_colormap,
+as appropriate after setting png_image::format to the format of the color-map
+to be read or written. Applications may check the value of
+PNG_FORMAT_FLAG_COLORMAP to see if they have called the colormap API. The
+format of the color-map may be extracted using the following macro.
+
+ PNG_FORMAT_OF_COLORMAP(fmt) ((fmt) & ~PNG_FORMAT_FLAG_COLORMAP)
+
+PNG_IMAGE macros
+
+These are convenience macros to derive information from a png_image
+structure. The PNG_IMAGE_SAMPLE_ macros return values appropriate to the
+actual image sample values - either the entries in the color-map or the
+pixels in the image. The PNG_IMAGE_PIXEL_ macros return corresponding values
+for the pixels and will always return 1 after a call to
+png_image_{read,write}_colormap. The remaining macros return information
+about the rows in the image and the complete image.
+
+NOTE: All the macros that take a png_image::format parameter are compile time
+constants if the format parameter is, itself, a constant. Therefore these
+macros can be used in array declarations and case labels where required.
+Similarly the macros are also pre-processor constants (sizeof is not used) so
+they can be used in #if tests.
+
+First the information about the samples.
+
+ PNG_IMAGE_SAMPLE_CHANNELS(fmt)
+ Returns the total number of channels in a given format: 1..4
+
+ PNG_IMAGE_SAMPLE_COMPONENT_SIZE(fmt)
+ Returns the size in bytes of a single component of a pixel or color-map
+ entry (as appropriate) in the image.
+
+ PNG_IMAGE_SAMPLE_SIZE(fmt)
+ This is the size of the sample data for one sample. If the image is
+ color-mapped it is the size of one color-map entry (and image pixels are
+ one byte in size), otherwise it is the size of one image pixel.
+
+ PNG_IMAGE_COLORMAP_SIZE(fmt)
+ The size of the color-map required by the format; this is the size of the
+ color-map buffer passed to the png_image_{read,write}_colormap APIs, it is
+ a fixed number determined by the format so can easily be allocated on the
+ stack if necessary.
+
+#define PNG_IMAGE_MAXIMUM_COLORMAP_COMPONENTS(fmt)\
+ (PNG_IMAGE_SAMPLE_CHANNELS(fmt) * 256)
+ /* The maximum size of the color-map required by the format expressed in a
+ * count of components. This can be used to compile-time allocate a
+ * color-map:
+ *
+ * png_uint_16 colormap[PNG_IMAGE_MAXIMUM_COLORMAP_COMPONENTS(linear_fmt)];
+ *
+ * png_byte colormap[PNG_IMAGE_MAXIMUM_COLORMAP_COMPONENTS(sRGB_fmt)];
+ *
+ * Alternatively, use the PNG_IMAGE_COLORMAP_SIZE macro below to use the
+ * information from one of the png_image_begin_read_ APIs and dynamically
+ * allocate the required memory.
+ */
+
+
+Corresponding information about the pixels
+
+ PNG_IMAGE_PIXEL_(test,fmt)
+
+ PNG_IMAGE_PIXEL_CHANNELS(fmt)
+ The number of separate channels (components) in a pixel; 1 for a
+ color-mapped image.
+
+ PNG_IMAGE_PIXEL_COMPONENT_SIZE(fmt)\
+ The size, in bytes, of each component in a pixel; 1 for a color-mapped
+ image.
+
+ PNG_IMAGE_PIXEL_SIZE(fmt)
+ The size, in bytes, of a complete pixel; 1 for a color-mapped image.
+
+Information about the whole row, or whole image
+
+ PNG_IMAGE_ROW_STRIDE(image)
+ Returns the total number of components in a single row of the image; this
+ is the minimum 'row stride', the minimum count of components between each
+ row. For a color-mapped image this is the minimum number of bytes in a
+ row.
+
+ If you need the stride measured in bytes, row_stride_bytes is
+ PNG_IMAGE_ROW_STRIDE(image) * PNG_IMAGE_PIXEL_COMPONENT_SIZE(fmt)
+ plus any padding bytes that your application might need, for example
+ to start the next row on a 4-byte boundary.
+
+ PNG_IMAGE_BUFFER_SIZE(image, row_stride)
+ Returns the size, in bytes, of an image buffer given a png_image and a row
+ stride - the number of components to leave space for in each row. This
+ macro takes care of multiplying row_stride by PNG_IMAGE_PIXEL_COMONENT_SIZE
+ when the image has 2-byte components.
+
+ PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB == 0x01
+ This indicates the the RGB values of the in-memory bitmap do not
+ correspond to the red, green and blue end-points defined by sRGB.
+
+ PNG_IMAGE_FLAG_COLORMAP == 0x02
+ The PNG is color-mapped. If this flag is set png_image_read_colormap
+ can be used without further loss of image information. If it is not set
+ png_image_read_colormap will cause significant loss if the image has any
+
+READ APIs
+
+ The png_image passed to the read APIs must have been initialized by setting
+ the png_controlp field 'opaque' to NULL (or, better, memset the whole thing.)
+
+ int png_image_begin_read_from_file( png_imagep image,
+ const char *file_name)
+
+ The named file is opened for read and the image header
+ is filled in from the PNG header in the file.
+
+ int png_image_begin_read_from_stdio (png_imagep image,
+ FILE* file)
+
+ The PNG header is read from the stdio FILE object.
+
+ int png_image_begin_read_from_memory(png_imagep image,
+ png_const_voidp memory, png_size_t size)
+
+ The PNG header is read from the given memory buffer.
+
+ int png_image_finish_read(png_imagep image,
+ png_colorp background, void *buffer,
+ png_int_32 row_stride, void *colormap));
+
+ Finish reading the image into the supplied buffer and
+ clean up the png_image structure.
+
+ row_stride is the step, in png_byte or png_uint_16 units
+ as appropriate, between adjacent rows. A positive stride
+ indicates that the top-most row is first in the buffer -
+ the normal top-down arrangement. A negative stride
+ indicates that the bottom-most row is first in the buffer.
+
+ background need only be supplied if an alpha channel must
+ be removed from a png_byte format and the removal is to be
+ done by compositing on a solid color; otherwise it may be
+ NULL and any composition will be done directly onto the
+ buffer. The value is an sRGB color to use for the
+ background, for grayscale output the green channel is used.
+
+ For linear output removing the alpha channel is always done
+ by compositing on black.
+
+ void png_image_free(png_imagep image)
+
+ Free any data allocated by libpng in image->opaque,
+ setting the pointer to NULL. May be called at any time
+ after the structure is initialized.
+
+When the simplified API needs to convert between sRGB and linear colorspaces,
+the actual sRGB transfer curve defined in the sRGB specification (see the
+article at http://en.wikipedia.org/wiki/SRGB) is used, not the gamma=1/2.2
+approximation used elsewhere in libpng.
+
+WRITE APIS
+
+For write you must initialize a png_image structure to describe the image to
+be written:
+
+ version: must be set to PNG_IMAGE_VERSION
+ opaque: must be initialized to NULL
+ width: image width in pixels
+ height: image height in rows
+ format: the format of the data you wish to write
+ flags: set to 0 unless one of the defined flags applies; set
+ PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB for color format images
+ where the RGB values do not correspond to the colors in sRGB.
+ colormap_entries: set to the number of entries in the color-map (0 to 256)
+
+ int png_image_write_to_file, (png_imagep image,
+ const char *file, int convert_to_8bit, const void *buffer,
+ png_int_32 row_stride, const void *colormap));
+
+ Write the image to the named file.
+
+ int png_image_write_to_stdio(png_imagep image, FILE *file,
+ int convert_to_8_bit, const void *buffer,
+ png_int_32 row_stride, const void *colormap)
+
+ Write the image to the given (FILE*).
+
+With all write APIs if image is in one of the linear formats with
+(png_uint_16) data then setting convert_to_8_bit will cause the output to be
+a (png_byte) PNG gamma encoded according to the sRGB specification, otherwise
+a 16-bit linear encoded PNG file is written.
+
+With all APIs row_stride is handled as in the read APIs - it is the spacing
+from one row to the next in component sized units (float) and if negative
+indicates a bottom-up row layout in the buffer.
+
+Note that the write API does not support interlacing, sub-8-bit pixels,
+and indexed (paletted) images.
+
+VI. Modifying/Customizing libpng
+
+There are two issues here. The first is changing how libpng does
+standard things like memory allocation, input/output, and error handling.
+The second deals with more complicated things like adding new chunks,
+adding new transformations, and generally changing how libpng works.
+Both of those are compile-time issues; that is, they are generally
+determined at the time the code is written, and there is rarely a need
+to provide the user with a means of changing them.
+
+Memory allocation, input/output, and error handling
+
+All of the memory allocation, input/output, and error handling in libpng
+goes through callbacks that are user-settable. The default routines are
+in pngmem.c, pngrio.c, pngwio.c, and pngerror.c, respectively. To change
+these functions, call the appropriate png_set_*_fn() function.
+
+Memory allocation is done through the functions png_malloc(), png_calloc(),
+and png_free(). The png_malloc() and png_free() functions currently just
+call the standard C functions and png_calloc() calls png_malloc() and then
+clears the newly allocated memory to zero; note that png_calloc(png_ptr, size)
+is not the same as the calloc(number, size) function provided by stdlib.h.
+There is limited support for certain systems with segmented memory
+architectures and the types of pointers declared by png.h match this; you
+will have to use appropriate pointers in your application. If you prefer
+to use a different method of allocating and freeing data, you can use
+png_create_read_struct_2() or png_create_write_struct_2() to register your
+own functions as described above. These functions also provide a void
+pointer that can be retrieved via
+
+ mem_ptr=png_get_mem_ptr(png_ptr);
+
+Your replacement memory functions must have prototypes as follows:
+
+ png_voidp malloc_fn(png_structp png_ptr,
+ png_alloc_size_t size);
+
+ void free_fn(png_structp png_ptr, png_voidp ptr);
+
+Your malloc_fn() must return NULL in case of failure. The png_malloc()
+function will normally call png_error() if it receives a NULL from the
+system memory allocator or from your replacement malloc_fn().
+
+Your free_fn() will never be called with a NULL ptr, since libpng's
+png_free() checks for NULL before calling free_fn().
+
+Input/Output in libpng is done through png_read() and png_write(),
+which currently just call fread() and fwrite(). The FILE * is stored in
+png_struct and is initialized via png_init_io(). If you wish to change
+the method of I/O, the library supplies callbacks that you can set
+through the function png_set_read_fn() and png_set_write_fn() at run
+time, instead of calling the png_init_io() function. These functions
+also provide a void pointer that can be retrieved via the function
+png_get_io_ptr(). For example:
+
+ png_set_read_fn(png_structp read_ptr,
+ voidp read_io_ptr, png_rw_ptr read_data_fn)
+
+ png_set_write_fn(png_structp write_ptr,
+ voidp write_io_ptr, png_rw_ptr write_data_fn,
+ png_flush_ptr output_flush_fn);
+
+ voidp read_io_ptr = png_get_io_ptr(read_ptr);
+ voidp write_io_ptr = png_get_io_ptr(write_ptr);
+
+The replacement I/O functions must have prototypes as follows:
+
+ void user_read_data(png_structp png_ptr,
+ png_bytep data, png_size_t length);
+
+ void user_write_data(png_structp png_ptr,
+ png_bytep data, png_size_t length);
+
+ void user_flush_data(png_structp png_ptr);
+
+The user_read_data() function is responsible for detecting and
+handling end-of-data errors.
+
+Supplying NULL for the read, write, or flush functions sets them back
+to using the default C stream functions, which expect the io_ptr to
+point to a standard *FILE structure. It is probably a mistake
+to use NULL for one of write_data_fn and output_flush_fn but not both
+of them, unless you have built libpng with PNG_NO_WRITE_FLUSH defined.
+It is an error to read from a write stream, and vice versa.
+
+Error handling in libpng is done through png_error() and png_warning().
+Errors handled through png_error() are fatal, meaning that png_error()
+should never return to its caller. Currently, this is handled via
+setjmp() and longjmp() (unless you have compiled libpng with
+PNG_NO_SETJMP, in which case it is handled via PNG_ABORT()),
+but you could change this to do things like exit() if you should wish,
+as long as your function does not return.
+
+On non-fatal errors, png_warning() is called
+to print a warning message, and then control returns to the calling code.
+By default png_error() and png_warning() print a message on stderr via
+fprintf() unless the library is compiled with PNG_NO_CONSOLE_IO defined
+(because you don't want the messages) or PNG_NO_STDIO defined (because
+fprintf() isn't available). If you wish to change the behavior of the error
+functions, you will need to set up your own message callbacks. These
+functions are normally supplied at the time that the png_struct is created.
+It is also possible to redirect errors and warnings to your own replacement
+functions after png_create_*_struct() has been called by calling:
+
+ png_set_error_fn(png_structp png_ptr,
+ png_voidp error_ptr, png_error_ptr error_fn,
+ png_error_ptr warning_fn);
+
+ png_voidp error_ptr = png_get_error_ptr(png_ptr);
+
+If NULL is supplied for either error_fn or warning_fn, then the libpng
+default function will be used, calling fprintf() and/or longjmp() if a
+problem is encountered. The replacement error functions should have
+parameters as follows:
+
+ void user_error_fn(png_structp png_ptr,
+ png_const_charp error_msg);
+
+ void user_warning_fn(png_structp png_ptr,
+ png_const_charp warning_msg);
+
+The motivation behind using setjmp() and longjmp() is the C++ throw and
+catch exception handling methods. This makes the code much easier to write,
+as there is no need to check every return code of every function call.
+However, there are some uncertainties about the status of local variables
+after a longjmp, so the user may want to be careful about doing anything
+after setjmp returns non-zero besides returning itself. Consult your
+compiler documentation for more details. For an alternative approach, you
+may wish to use the "cexcept" facility (see http://cexcept.sourceforge.net),
+which is illustrated in pngvalid.c and in contrib/visupng.
+
+Beginning in libpng-1.4.0, the png_set_benign_errors() API became available.
+You can use this to handle certain errors (normally handled as errors)
+as warnings.
+
+ png_set_benign_errors (png_ptr, int allowed);
+
+ allowed: 0: treat png_benign_error() as an error.
+ 1: treat png_benign_error() as a warning.
+
+As of libpng-1.6.0, the default condition is to treat benign errors as
+warnings while reading and as errors while writing.
+
+Custom chunks
+
+If you need to read or write custom chunks, you may need to get deeper
+into the libpng code. The library now has mechanisms for storing
+and writing chunks of unknown type; you can even declare callbacks
+for custom chunks. However, this may not be good enough if the
+library code itself needs to know about interactions between your
+chunk and existing `intrinsic' chunks.
+
+If you need to write a new intrinsic chunk, first read the PNG
+specification. Acquire a first level of understanding of how it works.
+Pay particular attention to the sections that describe chunk names,
+and look at how other chunks were designed, so you can do things
+similarly. Second, check out the sections of libpng that read and
+write chunks. Try to find a chunk that is similar to yours and use
+it as a template. More details can be found in the comments inside
+the code. It is best to handle private or unknown chunks in a generic method,
+via callback functions, instead of by modifying libpng functions. This
+is illustrated in pngtest.c, which uses a callback function to handle a
+private "vpAg" chunk and the new "sTER" chunk, which are both unknown to
+libpng.
+
+If you wish to write your own transformation for the data, look through
+the part of the code that does the transformations, and check out some of
+the simpler ones to get an idea of how they work. Try to find a similar
+transformation to the one you want to add and copy off of it. More details
+can be found in the comments inside the code itself.
+
+Configuring for gui/windowing platforms:
+
+You will need to write new error and warning functions that use the GUI
+interface, as described previously, and set them to be the error and
+warning functions at the time that png_create_*_struct() is called,
+in order to have them available during the structure initialization.
+They can be changed later via png_set_error_fn(). On some compilers,
+you may also have to change the memory allocators (png_malloc, etc.).
+
+Configuring zlib:
+
+There are special functions to configure the compression. Perhaps the
+most useful one changes the compression level, which currently uses
+input compression values in the range 0 - 9. The library normally
+uses the default compression level (Z_DEFAULT_COMPRESSION = 6). Tests
+have shown that for a large majority of images, compression values in
+the range 3-6 compress nearly as well as higher levels, and do so much
+faster. For online applications it may be desirable to have maximum speed
+(Z_BEST_SPEED = 1). With versions of zlib after v0.99, you can also
+specify no compression (Z_NO_COMPRESSION = 0), but this would create
+files larger than just storing the raw bitmap. You can specify the
+compression level by calling:
+
+ #include zlib.h
+ png_set_compression_level(png_ptr, level);
+
+Another useful one is to reduce the memory level used by the library.
+The memory level defaults to 8, but it can be lowered if you are
+short on memory (running DOS, for example, where you only have 640K).
+Note that the memory level does have an effect on compression; among
+other things, lower levels will result in sections of incompressible
+data being emitted in smaller stored blocks, with a correspondingly
+larger relative overhead of up to 15% in the worst case.
+
+ #include zlib.h
+ png_set_compression_mem_level(png_ptr, level);
+
+The other functions are for configuring zlib. They are not recommended
+for normal use and may result in writing an invalid PNG file. See
+zlib.h for more information on what these mean.
+
+ #include zlib.h
+ png_set_compression_strategy(png_ptr,
+ strategy);
+
+ png_set_compression_window_bits(png_ptr,
+ window_bits);
+
+ png_set_compression_method(png_ptr, method);
+
+This controls the size of the IDAT chunks (default 8192):
+
+ png_set_compression_buffer_size(png_ptr, size);
+
+As of libpng version 1.5.4, additional APIs became
+available to set these separately for non-IDAT
+compressed chunks such as zTXt, iTXt, and iCCP:
+
+ #include zlib.h
+ #if PNG_LIBPNG_VER >= 10504
+ png_set_text_compression_level(png_ptr, level);
+
+ png_set_text_compression_mem_level(png_ptr, level);
+
+ png_set_text_compression_strategy(png_ptr,
+ strategy);
+
+ png_set_text_compression_window_bits(png_ptr,
+ window_bits);
+
+ png_set_text_compression_method(png_ptr, method);
+ #endif
+
+Controlling row filtering
+
+If you want to control whether libpng uses filtering or not, which
+filters are used, and how it goes about picking row filters, you
+can call one of these functions. The selection and configuration
+of row filters can have a significant impact on the size and
+encoding speed and a somewhat lesser impact on the decoding speed
+of an image. Filtering is enabled by default for RGB and grayscale
+images (with and without alpha), but not for paletted images nor
+for any images with bit depths less than 8 bits/pixel.
+
+The 'method' parameter sets the main filtering method, which is
+currently only '0' in the PNG 1.2 specification. The 'filters'
+parameter sets which filter(s), if any, should be used for each
+scanline. Possible values are PNG_ALL_FILTERS and PNG_NO_FILTERS
+to turn filtering on and off, respectively.
+
+Individual filter types are PNG_FILTER_NONE, PNG_FILTER_SUB,
+PNG_FILTER_UP, PNG_FILTER_AVG, PNG_FILTER_PAETH, which can be bitwise
+ORed together with '|' to specify one or more filters to use.
+These filters are described in more detail in the PNG specification.
+If you intend to change the filter type during the course of writing
+the image, you should start with flags set for all of the filters
+you intend to use so that libpng can initialize its internal
+structures appropriately for all of the filter types. (Note that this
+means the first row must always be adaptively filtered, because libpng
+currently does not allocate the filter buffers until png_write_row()
+is called for the first time.)
+
+ filters = PNG_FILTER_NONE | PNG_FILTER_SUB
+ PNG_FILTER_UP | PNG_FILTER_AVG |
+ PNG_FILTER_PAETH | PNG_ALL_FILTERS;
+
+ png_set_filter(png_ptr, PNG_FILTER_TYPE_BASE,
+ filters);
+ The second parameter can also be
+ PNG_INTRAPIXEL_DIFFERENCING if you are
+ writing a PNG to be embedded in a MNG
+ datastream. This parameter must be the
+ same as the value of filter_method used
+ in png_set_IHDR().
+
+It is also possible to influence how libpng chooses from among the
+available filters. This is done in one or both of two ways - by
+telling it how important it is to keep the same filter for successive
+rows, and by telling it the relative computational costs of the filters.
+
+ double weights[3] = {1.5, 1.3, 1.1},
+ costs[PNG_FILTER_VALUE_LAST] =
+ {1.0, 1.3, 1.3, 1.5, 1.7};
+
+ png_set_filter_heuristics(png_ptr,
+ PNG_FILTER_HEURISTIC_WEIGHTED, 3,
+ weights, costs);
+
+The weights are multiplying factors that indicate to libpng that the
+row filter should be the same for successive rows unless another row filter
+is that many times better than the previous filter. In the above example,
+if the previous 3 filters were SUB, SUB, NONE, the SUB filter could have a
+"sum of absolute differences" 1.5 x 1.3 times higher than other filters
+and still be chosen, while the NONE filter could have a sum 1.1 times
+higher than other filters and still be chosen. Unspecified weights are
+taken to be 1.0, and the specified weights should probably be declining
+like those above in order to emphasize recent filters over older filters.
+
+The filter costs specify for each filter type a relative decoding cost
+to be considered when selecting row filters. This means that filters
+with higher costs are less likely to be chosen over filters with lower
+costs, unless their "sum of absolute differences" is that much smaller.
+The costs do not necessarily reflect the exact computational speeds of
+the various filters, since this would unduly influence the final image
+size.
+
+Note that the numbers above were invented purely for this example and
+are given only to help explain the function usage. Little testing has
+been done to find optimum values for either the costs or the weights.
+
+Requesting debug printout
+
+The macro definition PNG_DEBUG can be used to request debugging
+printout. Set it to an integer value in the range 0 to 3. Higher
+numbers result in increasing amounts of debugging information. The
+information is printed to the "stderr" file, unless another file
+name is specified in the PNG_DEBUG_FILE macro definition.
+
+When PNG_DEBUG > 0, the following functions (macros) become available:
+
+ png_debug(level, message)
+ png_debug1(level, message, p1)
+ png_debug2(level, message, p1, p2)
+
+in which "level" is compared to PNG_DEBUG to decide whether to print
+the message, "message" is the formatted string to be printed,
+and p1 and p2 are parameters that are to be embedded in the string
+according to printf-style formatting directives. For example,
+
+ png_debug1(2, "foo=%d", foo);
+
+is expanded to
+
+ if (PNG_DEBUG > 2)
+ fprintf(PNG_DEBUG_FILE, "foo=%d\n", foo);
+
+When PNG_DEBUG is defined but is zero, the macros aren't defined, but you
+can still use PNG_DEBUG to control your own debugging:
+
+ #ifdef PNG_DEBUG
+ fprintf(stderr, ...
+ #endif
+
+When PNG_DEBUG = 1, the macros are defined, but only png_debug statements
+having level = 0 will be printed. There aren't any such statements in
+this version of libpng, but if you insert some they will be printed.
+
+VII. MNG support
+
+The MNG specification (available at http://www.libpng.org/pub/mng) allows
+certain extensions to PNG for PNG images that are embedded in MNG datastreams.
+Libpng can support some of these extensions. To enable them, use the
+png_permit_mng_features() function:
+
+ feature_set = png_permit_mng_features(png_ptr, mask)
+
+ mask is a png_uint_32 containing the bitwise OR of the
+ features you want to enable. These include
+ PNG_FLAG_MNG_EMPTY_PLTE
+ PNG_FLAG_MNG_FILTER_64
+ PNG_ALL_MNG_FEATURES
+
+ feature_set is a png_uint_32 that is the bitwise AND of
+ your mask with the set of MNG features that is
+ supported by the version of libpng that you are using.
+
+It is an error to use this function when reading or writing a standalone
+PNG file with the PNG 8-byte signature. The PNG datastream must be wrapped
+in a MNG datastream. As a minimum, it must have the MNG 8-byte signature
+and the MHDR and MEND chunks. Libpng does not provide support for these
+or any other MNG chunks; your application must provide its own support for
+them. You may wish to consider using libmng (available at
+http://www.libmng.com) instead.
+
+VIII. Changes to Libpng from version 0.88
+
+It should be noted that versions of libpng later than 0.96 are not
+distributed by the original libpng author, Guy Schalnat, nor by
+Andreas Dilger, who had taken over from Guy during 1996 and 1997, and
+distributed versions 0.89 through 0.96, but rather by another member
+of the original PNG Group, Glenn Randers-Pehrson. Guy and Andreas are
+still alive and well, but they have moved on to other things.
+
+The old libpng functions png_read_init(), png_write_init(),
+png_info_init(), png_read_destroy(), and png_write_destroy() have been
+moved to PNG_INTERNAL in version 0.95 to discourage their use. These
+functions will be removed from libpng version 1.4.0.
+
+The preferred method of creating and initializing the libpng structures is
+via the png_create_read_struct(), png_create_write_struct(), and
+png_create_info_struct() because they isolate the size of the structures
+from the application, allow version error checking, and also allow the
+use of custom error handling routines during the initialization, which
+the old functions do not. The functions png_read_destroy() and
+png_write_destroy() do not actually free the memory that libpng
+allocated for these structs, but just reset the data structures, so they
+can be used instead of png_destroy_read_struct() and
+png_destroy_write_struct() if you feel there is too much system overhead
+allocating and freeing the png_struct for each image read.
+
+Setting the error callbacks via png_set_message_fn() before
+png_read_init() as was suggested in libpng-0.88 is no longer supported
+because this caused applications that do not use custom error functions
+to fail if the png_ptr was not initialized to zero. It is still possible
+to set the error callbacks AFTER png_read_init(), or to change them with
+png_set_error_fn(), which is essentially the same function, but with a new
+name to force compilation errors with applications that try to use the old
+method.
+
+Support for the sCAL, iCCP, iTXt, and sPLT chunks was added at libpng-1.0.6;
+however, iTXt support was not enabled by default.
+
+Starting with version 1.0.7, you can find out which version of the library
+you are using at run-time:
+
+ png_uint_32 libpng_vn = png_access_version_number();
+
+The number libpng_vn is constructed from the major version, minor
+version with leading zero, and release number with leading zero,
+(e.g., libpng_vn for version 1.0.7 is 10007).
+
+Note that this function does not take a png_ptr, so you can call it
+before you've created one.
+
+You can also check which version of png.h you used when compiling your
+application:
+
+ png_uint_32 application_vn = PNG_LIBPNG_VER;
+
+IX. Changes to Libpng from version 1.0.x to 1.2.x
+
+Support for user memory management was enabled by default. To
+accomplish this, the functions png_create_read_struct_2(),
+png_create_write_struct_2(), png_set_mem_fn(), png_get_mem_ptr(),
+png_malloc_default(), and png_free_default() were added.
+
+Support for the iTXt chunk has been enabled by default as of
+version 1.2.41.
+
+Support for certain MNG features was enabled.
+
+Support for numbered error messages was added. However, we never got
+around to actually numbering the error messages. The function
+png_set_strip_error_numbers() was added (Note: the prototype for this
+function was inadvertently removed from png.h in PNG_NO_ASSEMBLER_CODE
+builds of libpng-1.2.15. It was restored in libpng-1.2.36).
+
+The png_malloc_warn() function was added at libpng-1.2.3. This issues
+a png_warning and returns NULL instead of aborting when it fails to
+acquire the requested memory allocation.
+
+Support for setting user limits on image width and height was enabled
+by default. The functions png_set_user_limits(), png_get_user_width_max(),
+and png_get_user_height_max() were added at libpng-1.2.6.
+
+The png_set_add_alpha() function was added at libpng-1.2.7.
+
+The function png_set_expand_gray_1_2_4_to_8() was added at libpng-1.2.9.
+Unlike png_set_gray_1_2_4_to_8(), the new function does not expand the
+tRNS chunk to alpha. The png_set_gray_1_2_4_to_8() function is
+deprecated.
+
+A number of macro definitions in support of runtime selection of
+assembler code features (especially Intel MMX code support) were
+added at libpng-1.2.0:
+
+ PNG_ASM_FLAG_MMX_SUPPORT_COMPILED
+ PNG_ASM_FLAG_MMX_SUPPORT_IN_CPU
+ PNG_ASM_FLAG_MMX_READ_COMBINE_ROW
+ PNG_ASM_FLAG_MMX_READ_INTERLACE
+ PNG_ASM_FLAG_MMX_READ_FILTER_SUB
+ PNG_ASM_FLAG_MMX_READ_FILTER_UP
+ PNG_ASM_FLAG_MMX_READ_FILTER_AVG
+ PNG_ASM_FLAG_MMX_READ_FILTER_PAETH
+ PNG_ASM_FLAGS_INITIALIZED
+ PNG_MMX_READ_FLAGS
+ PNG_MMX_FLAGS
+ PNG_MMX_WRITE_FLAGS
+ PNG_MMX_FLAGS
+
+We added the following functions in support of runtime
+selection of assembler code features:
+
+ png_get_mmx_flagmask()
+ png_set_mmx_thresholds()
+ png_get_asm_flags()
+ png_get_mmx_bitdepth_threshold()
+ png_get_mmx_rowbytes_threshold()
+ png_set_asm_flags()
+
+We replaced all of these functions with simple stubs in libpng-1.2.20,
+when the Intel assembler code was removed due to a licensing issue.
+
+These macros are deprecated:
+
+ PNG_READ_TRANSFORMS_NOT_SUPPORTED
+ PNG_PROGRESSIVE_READ_NOT_SUPPORTED
+ PNG_NO_SEQUENTIAL_READ_SUPPORTED
+ PNG_WRITE_TRANSFORMS_NOT_SUPPORTED
+ PNG_READ_ANCILLARY_CHUNKS_NOT_SUPPORTED
+ PNG_WRITE_ANCILLARY_CHUNKS_NOT_SUPPORTED
+
+They have been replaced, respectively, by:
+
+ PNG_NO_READ_TRANSFORMS
+ PNG_NO_PROGRESSIVE_READ
+ PNG_NO_SEQUENTIAL_READ
+ PNG_NO_WRITE_TRANSFORMS
+ PNG_NO_READ_ANCILLARY_CHUNKS
+ PNG_NO_WRITE_ANCILLARY_CHUNKS
+
+PNG_MAX_UINT was replaced with PNG_UINT_31_MAX. It has been
+deprecated since libpng-1.0.16 and libpng-1.2.6.
+
+The function
+ png_check_sig(sig, num)
+was replaced with
+ !png_sig_cmp(sig, 0, num)
+It has been deprecated since libpng-0.90.
+
+The function
+ png_set_gray_1_2_4_to_8()
+which also expands tRNS to alpha was replaced with
+ png_set_expand_gray_1_2_4_to_8()
+which does not. It has been deprecated since libpng-1.0.18 and 1.2.9.
+
+X. Changes to Libpng from version 1.0.x/1.2.x to 1.4.x
+
+Private libpng prototypes and macro definitions were moved from
+png.h and pngconf.h into a new pngpriv.h header file.
+
+Functions png_set_benign_errors(), png_benign_error(), and
+png_chunk_benign_error() were added.
+
+Support for setting the maximum amount of memory that the application
+will allocate for reading chunks was added, as a security measure.
+The functions png_set_chunk_cache_max() and png_get_chunk_cache_max()
+were added to the library.
+
+We implemented support for I/O states by adding png_ptr member io_state
+and functions png_get_io_chunk_name() and png_get_io_state() in pngget.c
+
+We added PNG_TRANSFORM_GRAY_TO_RGB to the available high-level
+input transforms.
+
+Checking for and reporting of errors in the IHDR chunk is more thorough.
+
+Support for global arrays was removed, to improve thread safety.
+
+Some obsolete/deprecated macros and functions have been removed.
+
+Typecasted NULL definitions such as
+ #define png_voidp_NULL (png_voidp)NULL
+were eliminated. If you used these in your application, just use
+NULL instead.
+
+The png_struct and info_struct members "trans" and "trans_values" were
+changed to "trans_alpha" and "trans_color", respectively.
+
+The obsolete, unused pnggccrd.c and pngvcrd.c files and related makefiles
+were removed.
+
+The PNG_1_0_X and PNG_1_2_X macros were eliminated.
+
+The PNG_LEGACY_SUPPORTED macro was eliminated.
+
+Many WIN32_WCE #ifdefs were removed.
+
+The functions png_read_init(info_ptr), png_write_init(info_ptr),
+png_info_init(info_ptr), png_read_destroy(), and png_write_destroy()
+have been removed. They have been deprecated since libpng-0.95.
+
+The png_permit_empty_plte() was removed. It has been deprecated
+since libpng-1.0.9. Use png_permit_mng_features() instead.
+
+We removed the obsolete stub functions png_get_mmx_flagmask(),
+png_set_mmx_thresholds(), png_get_asm_flags(),
+png_get_mmx_bitdepth_threshold(), png_get_mmx_rowbytes_threshold(),
+png_set_asm_flags(), and png_mmx_supported()
+
+We removed the obsolete png_check_sig(), png_memcpy_check(), and
+png_memset_check() functions. Instead use !png_sig_cmp(), memcpy(),
+and memset(), respectively.
+
+The function png_set_gray_1_2_4_to_8() was removed. It has been
+deprecated since libpng-1.0.18 and 1.2.9, when it was replaced with
+png_set_expand_gray_1_2_4_to_8() because the former function also
+expanded any tRNS chunk to an alpha channel.
+
+Macros for png_get_uint_16, png_get_uint_32, and png_get_int_32
+were added and are used by default instead of the corresponding
+functions. Unfortunately,
+from libpng-1.4.0 until 1.4.4, the png_get_uint_16 macro (but not the
+function) incorrectly returned a value of type png_uint_32.
+
+We changed the prototype for png_malloc() from
+ png_malloc(png_structp png_ptr, png_uint_32 size)
+to
+ png_malloc(png_structp png_ptr, png_alloc_size_t size)
+
+This also applies to the prototype for the user replacement malloc_fn().
+
+The png_calloc() function was added and is used in place of
+of "png_malloc(); memset();" except in the case in png_read_png()
+where the array consists of pointers; in this case a "for" loop is used
+after the png_malloc() to set the pointers to NULL, to give robust.
+behavior in case the application runs out of memory part-way through
+the process.
+
+We changed the prototypes of png_get_compression_buffer_size() and
+png_set_compression_buffer_size() to work with png_size_t instead of
+png_uint_32.
+
+Support for numbered error messages was removed by default, since we
+never got around to actually numbering the error messages. The function
+png_set_strip_error_numbers() was removed from the library by default.
+
+The png_zalloc() and png_zfree() functions are no longer exported.
+The png_zalloc() function no longer zeroes out the memory that it
+allocates. Applications that called png_zalloc(png_ptr, number, size)
+can call png_calloc(png_ptr, number*size) instead, and can call
+png_free() instead of png_zfree().
+
+Support for dithering was disabled by default in libpng-1.4.0, because
+it has not been well tested and doesn't actually "dither".
+The code was not
+removed, however, and could be enabled by building libpng with
+PNG_READ_DITHER_SUPPORTED defined. In libpng-1.4.2, this support
+was re-enabled, but the function was renamed png_set_quantize() to
+reflect more accurately what it actually does. At the same time,
+the PNG_DITHER_[RED,GREEN_BLUE]_BITS macros were also renamed to
+PNG_QUANTIZE_[RED,GREEN,BLUE]_BITS, and PNG_READ_DITHER_SUPPORTED
+was renamed to PNG_READ_QUANTIZE_SUPPORTED.
+
+We removed the trailing '.' from the warning and error messages.
+
+XI. Changes to Libpng from version 1.4.x to 1.5.x
+
+From libpng-1.4.0 until 1.4.4, the png_get_uint_16 macro (but not the
+function) incorrectly returned a value of type png_uint_32.
+The incorrect macro was removed from libpng-1.4.5.
+
+Checking for invalid palette index on write was added at libpng
+1.5.10. If a pixel contains an invalid (out-of-range) index libpng issues
+a benign error. This is enabled by default because this condition is an
+error according to the PNG specification, Clause 11.3.2, but the error can
+be ignored in each png_ptr with
+
+ png_set_check_for_invalid_index(png_ptr, allowed);
+
+ allowed - one of
+ 0: disable benign error (accept the
+ invalid data without warning).
+ 1: enable benign error (treat the
+ invalid data as an error or a
+ warning).
+
+If the error is ignored, or if png_benign_error() treats it as a warning,
+any invalid pixels are decoded as opaque black by the decoder and written
+as-is by the encoder.
+
+Retrieving the maximum palette index found was added at libpng-1.5.15.
+This statement must appear after png_read_png() or png_read_image() while
+reading, and after png_write_png() or png_write_image() while writing.
+
+ int max_palette = png_get_palette_max(png_ptr, info_ptr);
+
+This will return the maximum palette index found in the image, or "-1" if
+the palette was not checked, or "0" if no palette was found. Note that this
+does not account for any palette index used by ancillary chunks such as the
+bKGD chunk; you must check those separately to determine the maximum
+palette index actually used.
+
+There are no substantial API changes between the non-deprecated parts of
+the 1.4.5 API and the 1.5.0 API; however, the ability to directly access
+members of the main libpng control structures, png_struct and png_info,
+deprecated in earlier versions of libpng, has been completely removed from
+libpng 1.5.
+
+We no longer include zlib.h in png.h. The include statement has been moved
+to pngstruct.h, where it is not accessible by applications. Applications that
+need access to information in zlib.h will need to add the '#include "zlib.h"'
+directive. It does not matter whether this is placed prior to or after
+the '"#include png.h"' directive.
+
+The png_sprintf(), png_strcpy(), and png_strncpy() macros are no longer used
+and were removed.
+
+We moved the png_strlen(), png_memcpy(), png_memset(), and png_memcmp()
+macros into a private header file (pngpriv.h) that is not accessible to
+applications.
+
+In png_get_iCCP, the type of "profile" was changed from png_charpp
+to png_bytepp, and in png_set_iCCP, from png_charp to png_const_bytep.
+
+There are changes of form in png.h, including new and changed macros to
+declare parts of the API. Some API functions with arguments that are
+pointers to data not modified within the function have been corrected to
+declare these arguments with PNG_CONST.
+
+Much of the internal use of C macros to control the library build has also
+changed and some of this is visible in the exported header files, in
+particular the use of macros to control data and API elements visible
+during application compilation may require significant revision to
+application code. (It is extremely rare for an application to do this.)
+
+Any program that compiled against libpng 1.4 and did not use deprecated
+features or access internal library structures should compile and work
+against libpng 1.5, except for the change in the prototype for
+png_get_iCCP() and png_set_iCCP() API functions mentioned above.
+
+libpng 1.5.0 adds PNG_ PASS macros to help in the reading and writing of
+interlaced images. The macros return the number of rows and columns in
+each pass and information that can be used to de-interlace and (if
+absolutely necessary) interlace an image.
+
+libpng 1.5.0 adds an API png_longjmp(png_ptr, value). This API calls
+the application-provided png_longjmp_ptr on the internal, but application
+initialized, longjmp buffer. It is provided as a convenience to avoid
+the need to use the png_jmpbuf macro, which had the unnecessary side
+effect of resetting the internal png_longjmp_ptr value.
+
+libpng 1.5.0 includes a complete fixed point API. By default this is
+present along with the corresponding floating point API. In general the
+fixed point API is faster and smaller than the floating point one because
+the PNG file format used fixed point, not floating point. This applies
+even if the library uses floating point in internal calculations. A new
+macro, PNG_FLOATING_ARITHMETIC_SUPPORTED, reveals whether the library
+uses floating point arithmetic (the default) or fixed point arithmetic
+internally for performance critical calculations such as gamma correction.
+In some cases, the gamma calculations may produce slightly different
+results. This has changed the results in png_rgb_to_gray and in alpha
+composition (png_set_background for example). This applies even if the
+original image was already linear (gamma == 1.0) and, therefore, it is
+not necessary to linearize the image. This is because libpng has *not*
+been changed to optimize that case correctly, yet.
+
+Fixed point support for the sCAL chunk comes with an important caveat;
+the sCAL specification uses a decimal encoding of floating point values
+and the accuracy of PNG fixed point values is insufficient for
+representation of these values. Consequently a "string" API
+(png_get_sCAL_s and png_set_sCAL_s) is the only reliable way of reading
+arbitrary sCAL chunks in the absence of either the floating point API or
+internal floating point calculations. Starting with libpng-1.5.0, both
+of these functions are present when PNG_sCAL_SUPPORTED is defined. Prior
+to libpng-1.5.0, their presence also depended upon PNG_FIXED_POINT_SUPPORTED
+being defined and PNG_FLOATING_POINT_SUPPORTED not being defined.
+
+Applications no longer need to include the optional distribution header
+file pngusr.h or define the corresponding macros during application
+build in order to see the correct variant of the libpng API. From 1.5.0
+application code can check for the corresponding _SUPPORTED macro:
+
+#ifdef PNG_INCH_CONVERSIONS_SUPPORTED
+ /* code that uses the inch conversion APIs. */
+#endif
+
+This macro will only be defined if the inch conversion functions have been
+compiled into libpng. The full set of macros, and whether or not support
+has been compiled in, are available in the header file pnglibconf.h.
+This header file is specific to the libpng build. Notice that prior to
+1.5.0 the _SUPPORTED macros would always have the default definition unless
+reset by pngusr.h or by explicit settings on the compiler command line.
+These settings may produce compiler warnings or errors in 1.5.0 because
+of macro redefinition.
+
+Applications can now choose whether to use these macros or to call the
+corresponding function by defining PNG_USE_READ_MACROS or
+PNG_NO_USE_READ_MACROS before including png.h. Notice that this is
+only supported from 1.5.0; defining PNG_NO_USE_READ_MACROS prior to 1.5.0
+will lead to a link failure.
+
+Prior to libpng-1.5.4, the zlib compressor used the same set of parameters
+when compressing the IDAT data and textual data such as zTXt and iCCP.
+In libpng-1.5.4 we reinitialized the zlib stream for each type of data.
+We added five png_set_text_*() functions for setting the parameters to
+use with textual data.
+
+Prior to libpng-1.5.4, the PNG_READ_16_TO_8_ACCURATE_SCALE_SUPPORTED
+option was off by default, and slightly inaccurate scaling occurred.
+This option can no longer be turned off, and the choice of accurate
+or inaccurate 16-to-8 scaling is by using the new png_set_scale_16_to_8()
+API for accurate scaling or the old png_set_strip_16_to_8() API for simple
+chopping. In libpng-1.5.4, the PNG_READ_16_TO_8_ACCURATE_SCALE_SUPPORTED
+macro became PNG_READ_SCALE_16_TO_8_SUPPORTED, and the PNG_READ_16_TO_8
+macro became PNG_READ_STRIP_16_TO_8_SUPPORTED, to enable the two
+png_set_*_16_to_8() functions separately.
+
+Prior to libpng-1.5.4, the png_set_user_limits() function could only be
+used to reduce the width and height limits from the value of
+PNG_USER_WIDTH_MAX and PNG_USER_HEIGHT_MAX, although this document said
+that it could be used to override them. Now this function will reduce or
+increase the limits.
+
+Starting in libpng-1.5.10, the user limits can be set en masse with the
+configuration option PNG_SAFE_LIMITS_SUPPORTED. If this option is enabled,
+a set of "safe" limits is applied in pngpriv.h. These can be overridden by
+application calls to png_set_user_limits(), png_set_user_chunk_cache_max(),
+and/or png_set_user_malloc_max() that increase or decrease the limits. Also,
+in libpng-1.5.10 the default width and height limits were increased
+from 1,000,000 to 0x7ffffff (i.e., made unlimited). Therefore, the
+limits are now
+ default safe
+ png_user_width_max 0x7fffffff 1,000,000
+ png_user_height_max 0x7fffffff 1,000,000
+ png_user_chunk_cache_max 0 (unlimited) 128
+ png_user_chunk_malloc_max 0 (unlimited) 8,000,000
+
+The png_set_option() function (and the "options" member of the png struct) was
+added to libpng-1.5.15.
+
+The library now supports a complete fixed point implementation and can
+thus be used on systems that have no floating point support or very
+limited or slow support. Previously gamma correction, an essential part
+of complete PNG support, required reasonably fast floating point.
+
+As part of this the choice of internal implementation has been made
+independent of the choice of fixed versus floating point APIs and all the
+missing fixed point APIs have been implemented.
+
+The exact mechanism used to control attributes of API functions has
+changed, as described in the INSTALL file.
+
+A new test program, pngvalid, is provided in addition to pngtest.
+pngvalid validates the arithmetic accuracy of the gamma correction
+calculations and includes a number of validations of the file format.
+A subset of the full range of tests is run when "make check" is done
+(in the 'configure' build.) pngvalid also allows total allocated memory
+usage to be evaluated and performs additional memory overwrite validation.
+
+Many changes to individual feature macros have been made. The following
+are the changes most likely to be noticed by library builders who
+configure libpng:
+
+1) All feature macros now have consistent naming:
+
+#define PNG_NO_feature turns the feature off
+#define PNG_feature_SUPPORTED turns the feature on
+
+pnglibconf.h contains one line for each feature macro which is either:
+
+#define PNG_feature_SUPPORTED
+
+if the feature is supported or:
+
+/*#undef PNG_feature_SUPPORTED*/
+
+if it is not. Library code consistently checks for the 'SUPPORTED' macro.
+It does not, and libpng applications should not, check for the 'NO' macro
+which will not normally be defined even if the feature is not supported.
+The 'NO' macros are only used internally for setting or not setting the
+corresponding 'SUPPORTED' macros.
+
+Compatibility with the old names is provided as follows:
+
+PNG_INCH_CONVERSIONS turns on PNG_INCH_CONVERSIONS_SUPPORTED
+
+And the following definitions disable the corresponding feature:
+
+PNG_SETJMP_NOT_SUPPORTED disables SETJMP
+PNG_READ_TRANSFORMS_NOT_SUPPORTED disables READ_TRANSFORMS
+PNG_NO_READ_COMPOSITED_NODIV disables READ_COMPOSITE_NODIV
+PNG_WRITE_TRANSFORMS_NOT_SUPPORTED disables WRITE_TRANSFORMS
+PNG_READ_ANCILLARY_CHUNKS_NOT_SUPPORTED disables READ_ANCILLARY_CHUNKS
+PNG_WRITE_ANCILLARY_CHUNKS_NOT_SUPPORTED disables WRITE_ANCILLARY_CHUNKS
+
+Library builders should remove use of the above, inconsistent, names.
+
+2) Warning and error message formatting was previously conditional on
+the STDIO feature. The library has been changed to use the
+CONSOLE_IO feature instead. This means that if CONSOLE_IO is disabled
+the library no longer uses the printf(3) functions, even though the
+default read/write implementations use (FILE) style stdio.h functions.
+
+3) Three feature macros now control the fixed/floating point decisions:
+
+PNG_FLOATING_POINT_SUPPORTED enables the floating point APIs
+
+PNG_FIXED_POINT_SUPPORTED enables the fixed point APIs; however, in
+practice these are normally required internally anyway (because the PNG
+file format is fixed point), therefore in most cases PNG_NO_FIXED_POINT
+merely stops the function from being exported.
+
+PNG_FLOATING_ARITHMETIC_SUPPORTED chooses between the internal floating
+point implementation or the fixed point one. Typically the fixed point
+implementation is larger and slower than the floating point implementation
+on a system that supports floating point; however, it may be faster on a
+system which lacks floating point hardware and therefore uses a software
+emulation.
+
+4) Added PNG_{READ,WRITE}_INT_FUNCTIONS_SUPPORTED. This allows the
+functions to read and write ints to be disabled independently of
+PNG_USE_READ_MACROS, which allows libpng to be built with the functions
+even though the default is to use the macros - this allows applications
+to choose at app buildtime whether or not to use macros (previously
+impossible because the functions weren't in the default build.)
+
+XII. Changes to Libpng from version 1.5.x to 1.6.x
+
+A "simplified API" has been added (see documentation in png.h and a simple
+example in contrib/examples/pngtopng.c). The new publicly visible API
+includes the following:
+
+ macros:
+ PNG_FORMAT_*
+ PNG_IMAGE_*
+ structures:
+ png_control
+ png_image
+ read functions
+ png_image_begin_read_from_file()
+ png_image_begin_read_from_stdio()
+ png_image_begin_read_from_memory()
+ png_image_finish_read()
+ png_image_free()
+ write functions
+ png_image_write_to_file()
+ png_image_write_to_stdio()
+
+Starting with libpng-1.6.0, you can configure libpng to prefix all exported
+symbols, using the PNG_PREFIX macro.
+
+We no longer include string.h in png.h. The include statement has been moved
+to pngpriv.h, where it is not accessible by applications. Applications that
+need access to information in string.h must add an '#include <string.h>'
+directive. It does not matter whether this is placed prior to or after
+the '#include "png.h"' directive.
+
+The following API are now DEPRECATED:
+ png_info_init_3()
+ png_convert_to_rfc1123() which has been replaced
+ with png_convert_to_rfc1123_buffer()
+ png_malloc_default()
+ png_free_default()
+ png_reset_zstream()
+
+The following have been removed:
+ png_get_io_chunk_name(), which has been replaced
+ with png_get_io_chunk_type(). The new
+ function returns a 32-bit integer instead of
+ a string.
+ The png_sizeof(), png_strlen(), png_memcpy(), png_memcmp(), and
+ png_memset() macros are no longer used in the libpng sources and
+ have been removed. These had already been made invisible to applications
+ (i.e., defined in the private pngpriv.h header file) since libpng-1.5.0.
+
+The signatures of many exported functions were changed, such that
+ png_structp became png_structrp or png_const_structrp
+ png_infop became png_inforp or png_const_inforp
+where "rp" indicates a "restricted pointer".
+
+The support for FAR/far types has been eliminated and the definition of
+png_alloc_size_t is now controlled by a flag so that 'small size_t' systems
+can select it if necessary.
+
+Error detection in some chunks has improved; in particular the iCCP chunk
+reader now does pretty complete validation of the basic format. Some bad
+profiles that were previously accepted are now accepted with a warning or
+rejected, depending upon the png_set_benign_errors() setting, in particular
+the very old broken Microsoft/HP 3144-byte sRGB profile. Starting with
+libpng-1.6.11, recognizing and checking sRGB profiles can be avoided by
+means of
+
+ #if defined(PNG_SKIP_sRGB_CHECK_PROFILE) && \
+ defined(PNG_SET_OPTION_SUPPORTED)
+ png_set_option(png_ptr, PNG_SKIP_sRGB_CHECK_PROFILE,
+ PNG_OPTION_ON);
+ #endif
+
+It's not a good idea to do this if you are using the "simplified API",
+which needs to be able to recognize sRGB profiles conveyed via the iCCP
+chunk.
+
+The PNG spec requirement that only grayscale profiles may appear in images
+with color type 0 or 4 and that even if the image only contains gray pixels,
+only RGB profiles may appear in images with color type 2, 3, or 6, is now
+enforced. The sRGB chunk is allowed to appear in images with any color type
+and is interpreted by libpng to convey a one-tracer-curve gray profile or a
+three-tracer-curve RGB profile as appropriate.
+
+Prior to libpng-1.6.0 a warning would be issued if the iTXt chunk contained
+an empty language field or an empty translated keyword. Both of these
+are allowed by the PNG specification, so these warnings are no longer issued.
+
+The library now issues an error if the application attempts to set a
+transform after it calls png_read_update_info() or if it attempts to call
+both png_read_update_info() and png_start_read_image() or to call either
+of them more than once.
+
+The default condition for benign_errors is now to treat benign errors as
+warnings while reading and as errors while writing.
+
+The library now issues a warning if both background processing and RGB to
+gray are used when gamma correction happens. As with previous versions of
+the library the results are numerically very incorrect in this case.
+
+There are some minor arithmetic changes in some transforms such as
+png_set_background(), that might be detected by certain regression tests.
+
+Unknown chunk handling has been improved internally, without any API change.
+This adds more correct option control of the unknown handling, corrects
+a pre-existing bug where the per-chunk 'keep' setting is ignored, and makes
+it possible to skip IDAT chunks in the sequential reader.
+
+The machine-generated configure files are no longer included in branches
+libpng16 and later of the GIT repository. They continue to be included
+in the tarball releases, however.
+
+Libpng-1.6.0 through 1.6.2 used the CMF bytes at the beginning of the IDAT
+stream to set the size of the sliding window for reading instead of using the
+default 32-kbyte sliding window size. It was discovered that there are
+hundreds of PNG files in the wild that have incorrect CMF bytes that caused
+zlib to issue the "invalid distance too far back" error and reject the file.
+Libpng-1.6.3 and later calculate their own safe CMF from the image dimensions,
+provide a way to revert to the libpng-1.5.x behavior (ignoring the CMF bytes
+and using a 32-kbyte sliding window), by using
+
+ png_set_option(png_ptr, PNG_MAXIMUM_INFLATE_WINDOW,
+ PNG_OPTION_ON);
+
+and provide a tool (contrib/tools/pngfix) for rewriting a PNG file while
+optimizing the CMF bytes in its IDAT chunk correctly.
+
+Libpng-1.6.0 and libpng-1.6.1 wrote uncompressed iTXt chunks with the wrong
+length, which resulted in PNG files that cannot be read beyond the bad iTXt
+chunk. This error was fixed in libpng-1.6.3, and a tool (called
+contrib/tools/png-fix-itxt) has been added to the libpng distribution.
+
+XIII. Detecting libpng
+
+The png_get_io_ptr() function has been present since libpng-0.88, has never
+changed, and is unaffected by conditional compilation macros. It is the
+best choice for use in configure scripts for detecting the presence of any
+libpng version since 0.88. In an autoconf "configure.in" you could use
+
+ AC_CHECK_LIB(png, png_get_io_ptr, ...
+
+XV. Source code repository
+
+Since about February 2009, version 1.2.34, libpng has been under "git" source
+control. The git repository was built from old libpng-x.y.z.tar.gz files
+going back to version 0.70. You can access the git repository (read only)
+at
+
+ git://git.code.sf.net/p/libpng/code
+
+or you can browse it with a web browser by selecting the "code" button at
+
+ https://sourceforge.net/projects/libpng
+
+Patches can be sent to glennrp at users.sourceforge.net or to
+png-mng-implement at lists.sourceforge.net or you can upload them to
+the libpng bug tracker at
+
+ http://libpng.sourceforge.net
+
+We also accept patches built from the tar or zip distributions, and
+simple verbal discriptions of bug fixes, reported either to the
+SourceForge bug tracker, to the png-mng-implement at lists.sf.net
+mailing list, or directly to glennrp.
+
+XV. Coding style
+
+Our coding style is similar to the "Allman" style
+(See http://en.wikipedia.org/wiki/Indent_style#Allman_style), with curly
+braces on separate lines:
+
+ if (condition)
+ {
+ action;
+ }
+
+ else if (another condition)
+ {
+ another action;
+ }
+
+The braces can be omitted from simple one-line actions:
+
+ if (condition)
+ return (0);
+
+We use 3-space indentation, except for continued statements which
+are usually indented the same as the first line of the statement
+plus four more spaces.
+
+For macro definitions we use 2-space indentation, always leaving the "#"
+in the first column.
+
+ #ifndef PNG_NO_FEATURE
+ # ifndef PNG_FEATURE_SUPPORTED
+ # define PNG_FEATURE_SUPPORTED
+ # endif
+ #endif
+
+Comments appear with the leading "/*" at the same indentation as
+the statement that follows the comment:
+
+ /* Single-line comment */
+ statement;
+
+ /* This is a multiple-line
+ * comment.
+ */
+ statement;
+
+Very short comments can be placed after the end of the statement
+to which they pertain:
+
+ statement; /* comment */
+
+We don't use C++ style ("//") comments. We have, however,
+used them in the past in some now-abandoned MMX assembler
+code.
+
+Functions and their curly braces are not indented, and
+exported functions are marked with PNGAPI:
+
+ /* This is a public function that is visible to
+ * application programmers. It does thus-and-so.
+ */
+ void PNGAPI
+ png_exported_function(png_ptr, png_info, foo)
+ {
+ body;
+ }
+
+The return type and decorations are placed on a separate line
+ahead of the function name, as illustrated above.
+
+The prototypes for all exported functions appear in png.h,
+above the comment that says
+
+ /* Maintainer: Put new public prototypes here ... */
+
+We mark all non-exported functions with "/* PRIVATE */"":
+
+ void /* PRIVATE */
+ png_non_exported_function(png_ptr, png_info, foo)
+ {
+ body;
+ }
+
+The prototypes for non-exported functions (except for those in
+pngtest) appear in pngpriv.h above the comment that says
+
+ /* Maintainer: Put new private prototypes here ^ */
+
+To avoid polluting the global namespace, the names of all exported
+functions and variables begin with "png_", and all publicly visible C
+preprocessor macros begin with "PNG". We request that applications that
+use libpng *not* begin any of their own symbols with either of these strings.
+
+We put a space after the "sizeof" operator and we omit the
+optional parentheses around its argument when the argument
+is an expression, not a type name, and we always enclose the
+sizeof operator, with its argument, in parentheses:
+
+ (sizeof (png_uint_32))
+ (sizeof array)
+
+Prior to libpng-1.6.0 we used a "png_sizeof()" macro, formatted as
+though it were a function.
+
+Control keywords if, for, while, and switch are always followed by a space
+to distinguish them from function calls, which have no trailing space.
+
+We put a space after each comma and after each semicolon
+in "for" statements, and we put spaces before and after each
+C binary operator and after "for" or "while", and before
+"?". We don't put a space between a typecast and the expression
+being cast, nor do we put one between a function name and the
+left parenthesis that follows it:
+
+ for (i = 2; i > 0; --i)
+ y[i] = a(x) + (int)b;
+
+We prefer #ifdef and #ifndef to #if defined() and #if !defined()
+when there is only one macro being tested. We always use parentheses
+with "defined".
+
+We prefer to express integers that are used as bit masks in hex format,
+with an even number of lower-case hex digits (e.g., 0x00, 0xff, 0x0100).
+
+We prefer to use underscores in variable names rather than camelCase, except
+for a few type names that we inherit from zlib.h.
+
+We prefer "if (something != 0)" and "if (something == 0)"
+over "if (something)" and if "(!something)", respectively.
+
+We do not use the TAB character for indentation in the C sources.
+
+Lines do not exceed 80 characters.
+
+Other rules can be inferred by inspecting the libpng source.
+
+XVI. Y2K Compliance in libpng
+
+March 26, 2015
+
+Since the PNG Development group is an ad-hoc body, we can't make
+an official declaration.
+
+This is your unofficial assurance that libpng from version 0.71 and
+upward through 1.6.17 are Y2K compliant. It is my belief that earlier
+versions were also Y2K compliant.
+
+Libpng only has two year fields. One is a 2-byte unsigned integer
+that will hold years up to 65535. The other, which is deprecated,
+holds the date in text format, and will hold years up to 9999.
+
+The integer is
+ "png_uint_16 year" in png_time_struct.
+
+The string is
+ "char time_buffer[29]" in png_struct. This is no longer used
+in libpng-1.6.x and will be removed from libpng-1.7.0.
+
+There are seven time-related functions:
+
+ png_convert_to_rfc_1123_buffer() in png.c
+ (formerly png_convert_to_rfc_1152() in error, and
+ also formerly png_convert_to_rfc_1123())
+ png_convert_from_struct_tm() in pngwrite.c, called
+ in pngwrite.c
+ png_convert_from_time_t() in pngwrite.c
+ png_get_tIME() in pngget.c
+ png_handle_tIME() in pngrutil.c, called in pngread.c
+ png_set_tIME() in pngset.c
+ png_write_tIME() in pngwutil.c, called in pngwrite.c
+
+All appear to handle dates properly in a Y2K environment. The
+png_convert_from_time_t() function calls gmtime() to convert from system
+clock time, which returns (year - 1900), which we properly convert to
+the full 4-digit year. There is a possibility that applications using
+libpng are not passing 4-digit years into the png_convert_to_rfc_1123()
+function, or that they are incorrectly passing only a 2-digit year
+instead of "year - 1900" into the png_convert_from_struct_tm() function,
+but this is not under our control. The libpng documentation has always
+stated that it works with 4-digit years, and the APIs have been
+documented as such.
+
+The tIME chunk itself is also Y2K compliant. It uses a 2-byte unsigned
+integer to hold the year, and can hold years as large as 65535.
+
+zlib, upon which libpng depends, is also Y2K compliant. It contains
+no date-related code.
+
+
+ Glenn Randers-Pehrson
+ libpng maintainer
+ PNG Development Group
--- /dev/null
+
+/* png.c - location for general purpose libpng functions
+ *
+ * Last changed in libpng 1.6.17 [March 26, 2015]
+ * Copyright (c) 1998-2015 Glenn Randers-Pehrson
+ * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
+ * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ */
+
+#include "pngpriv.h"
+
+/* Generate a compiler error if there is an old png.h in the search path. */
+typedef png_libpng_version_1_6_17 Your_png_h_is_not_version_1_6_17;
+
+/* Tells libpng that we have already handled the first "num_bytes" bytes
+ * of the PNG file signature. If the PNG data is embedded into another
+ * stream we can set num_bytes = 8 so that libpng will not attempt to read
+ * or write any of the magic bytes before it starts on the IHDR.
+ */
+
+#ifdef PNG_READ_SUPPORTED
+void PNGAPI
+png_set_sig_bytes(png_structrp png_ptr, int num_bytes)
+{
+ png_debug(1, "in png_set_sig_bytes");
+
+ if (png_ptr == NULL)
+ return;
+
+ if (num_bytes > 8)
+ png_error(png_ptr, "Too many bytes for PNG signature");
+
+ png_ptr->sig_bytes = (png_byte)((num_bytes < 0 ? 0 : num_bytes) & 0xff);
+}
+
+/* Checks whether the supplied bytes match the PNG signature. We allow
+ * checking less than the full 8-byte signature so that those apps that
+ * already read the first few bytes of a file to determine the file type
+ * can simply check the remaining bytes for extra assurance. Returns
+ * an integer less than, equal to, or greater than zero if sig is found,
+ * respectively, to be less than, to match, or be greater than the correct
+ * PNG signature (this is the same behavior as strcmp, memcmp, etc).
+ */
+int PNGAPI
+png_sig_cmp(png_const_bytep sig, png_size_t start, png_size_t num_to_check)
+{
+ png_byte png_signature[8] = {137, 80, 78, 71, 13, 10, 26, 10};
+
+ if (num_to_check > 8)
+ num_to_check = 8;
+
+ else if (num_to_check < 1)
+ return (-1);
+
+ if (start > 7)
+ return (-1);
+
+ if (start + num_to_check > 8)
+ num_to_check = 8 - start;
+
+ return ((int)(memcmp(&sig[start], &png_signature[start], num_to_check)));
+}
+
+#endif /* READ */
+
+#if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
+/* Function to allocate memory for zlib */
+PNG_FUNCTION(voidpf /* PRIVATE */,
+png_zalloc,(voidpf png_ptr, uInt items, uInt size),PNG_ALLOCATED)
+{
+ png_alloc_size_t num_bytes = size;
+
+ if (png_ptr == NULL)
+ return NULL;
+
+ if (items >= (~(png_alloc_size_t)0)/size)
+ {
+ png_warning (png_voidcast(png_structrp, png_ptr),
+ "Potential overflow in png_zalloc()");
+ return NULL;
+ }
+
+ num_bytes *= items;
+ return png_malloc_warn(png_voidcast(png_structrp, png_ptr), num_bytes);
+}
+
+/* Function to free memory for zlib */
+void /* PRIVATE */
+png_zfree(voidpf png_ptr, voidpf ptr)
+{
+ png_free(png_voidcast(png_const_structrp,png_ptr), ptr);
+}
+
+/* Reset the CRC variable to 32 bits of 1's. Care must be taken
+ * in case CRC is > 32 bits to leave the top bits 0.
+ */
+void /* PRIVATE */
+png_reset_crc(png_structrp png_ptr)
+{
+ /* The cast is safe because the crc is a 32 bit value. */
+ png_ptr->crc = (png_uint_32)crc32(0, Z_NULL, 0);
+}
+
+/* Calculate the CRC over a section of data. We can only pass as
+ * much data to this routine as the largest single buffer size. We
+ * also check that this data will actually be used before going to the
+ * trouble of calculating it.
+ */
+void /* PRIVATE */
+png_calculate_crc(png_structrp png_ptr, png_const_bytep ptr, png_size_t length)
+{
+ int need_crc = 1;
+
+ if (PNG_CHUNK_ANCILLARY(png_ptr->chunk_name) != 0)
+ {
+ if ((png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_MASK) ==
+ (PNG_FLAG_CRC_ANCILLARY_USE | PNG_FLAG_CRC_ANCILLARY_NOWARN))
+ need_crc = 0;
+ }
+
+ else /* critical */
+ {
+ if ((png_ptr->flags & PNG_FLAG_CRC_CRITICAL_IGNORE) != 0)
+ need_crc = 0;
+ }
+
+ /* 'uLong' is defined in zlib.h as unsigned long; this means that on some
+ * systems it is a 64 bit value. crc32, however, returns 32 bits so the
+ * following cast is safe. 'uInt' may be no more than 16 bits, so it is
+ * necessary to perform a loop here.
+ */
+ if (need_crc != 0 && length > 0)
+ {
+ uLong crc = png_ptr->crc; /* Should never issue a warning */
+
+ do
+ {
+ uInt safe_length = (uInt)length;
+#ifndef __COVERITY__
+ if (safe_length == 0)
+ safe_length = (uInt)-1; /* evil, but safe */
+#endif
+
+ crc = crc32(crc, ptr, safe_length);
+
+ /* The following should never issue compiler warnings; if they do the
+ * target system has characteristics that will probably violate other
+ * assumptions within the libpng code.
+ */
+ ptr += safe_length;
+ length -= safe_length;
+ }
+ while (length > 0);
+
+ /* And the following is always safe because the crc is only 32 bits. */
+ png_ptr->crc = (png_uint_32)crc;
+ }
+}
+
+/* Check a user supplied version number, called from both read and write
+ * functions that create a png_struct.
+ */
+int
+png_user_version_check(png_structrp png_ptr, png_const_charp user_png_ver)
+{
+ /* Libpng versions 1.0.0 and later are binary compatible if the version
+ * string matches through the second '.'; we must recompile any
+ * applications that use any older library version.
+ */
+
+ if (user_png_ver != NULL)
+ {
+ int i = -1;
+ int found_dots = 0;
+
+ do
+ {
+ i++;
+ if (user_png_ver[i] != PNG_LIBPNG_VER_STRING[i])
+ png_ptr->flags |= PNG_FLAG_LIBRARY_MISMATCH;
+ if (user_png_ver[i] == '.')
+ found_dots++;
+ } while (found_dots < 2 && user_png_ver[i] != 0 &&
+ PNG_LIBPNG_VER_STRING[i] != 0);
+ }
+
+ else
+ png_ptr->flags |= PNG_FLAG_LIBRARY_MISMATCH;
+
+ if ((png_ptr->flags & PNG_FLAG_LIBRARY_MISMATCH) != 0)
+ {
+#ifdef PNG_WARNINGS_SUPPORTED
+ size_t pos = 0;
+ char m[128];
+
+ pos = png_safecat(m, (sizeof m), pos,
+ "Application built with libpng-");
+ pos = png_safecat(m, (sizeof m), pos, user_png_ver);
+ pos = png_safecat(m, (sizeof m), pos, " but running with ");
+ pos = png_safecat(m, (sizeof m), pos, PNG_LIBPNG_VER_STRING);
+ PNG_UNUSED(pos)
+
+ png_warning(png_ptr, m);
+#endif
+
+#ifdef PNG_ERROR_NUMBERS_SUPPORTED
+ png_ptr->flags = 0;
+#endif
+
+ return 0;
+ }
+
+ /* Success return. */
+ return 1;
+}
+
+/* Generic function to create a png_struct for either read or write - this
+ * contains the common initialization.
+ */
+PNG_FUNCTION(png_structp /* PRIVATE */,
+png_create_png_struct,(png_const_charp user_png_ver, png_voidp error_ptr,
+ png_error_ptr error_fn, png_error_ptr warn_fn, png_voidp mem_ptr,
+ png_malloc_ptr malloc_fn, png_free_ptr free_fn),PNG_ALLOCATED)
+{
+ png_struct create_struct;
+# ifdef PNG_SETJMP_SUPPORTED
+ jmp_buf create_jmp_buf;
+# endif
+
+ /* This temporary stack-allocated structure is used to provide a place to
+ * build enough context to allow the user provided memory allocator (if any)
+ * to be called.
+ */
+ memset(&create_struct, 0, (sizeof create_struct));
+
+ /* Added at libpng-1.2.6 */
+# ifdef PNG_USER_LIMITS_SUPPORTED
+ create_struct.user_width_max = PNG_USER_WIDTH_MAX;
+ create_struct.user_height_max = PNG_USER_HEIGHT_MAX;
+
+# ifdef PNG_USER_CHUNK_CACHE_MAX
+ /* Added at libpng-1.2.43 and 1.4.0 */
+ create_struct.user_chunk_cache_max = PNG_USER_CHUNK_CACHE_MAX;
+# endif
+
+# ifdef PNG_USER_CHUNK_MALLOC_MAX
+ /* Added at libpng-1.2.43 and 1.4.1, required only for read but exists
+ * in png_struct regardless.
+ */
+ create_struct.user_chunk_malloc_max = PNG_USER_CHUNK_MALLOC_MAX;
+# endif
+# endif
+
+ /* The following two API calls simply set fields in png_struct, so it is safe
+ * to do them now even though error handling is not yet set up.
+ */
+# ifdef PNG_USER_MEM_SUPPORTED
+ png_set_mem_fn(&create_struct, mem_ptr, malloc_fn, free_fn);
+# else
+ PNG_UNUSED(mem_ptr)
+ PNG_UNUSED(malloc_fn)
+ PNG_UNUSED(free_fn)
+# endif
+
+ /* (*error_fn) can return control to the caller after the error_ptr is set,
+ * this will result in a memory leak unless the error_fn does something
+ * extremely sophisticated. The design lacks merit but is implicit in the
+ * API.
+ */
+ png_set_error_fn(&create_struct, error_ptr, error_fn, warn_fn);
+
+# ifdef PNG_SETJMP_SUPPORTED
+ if (!setjmp(create_jmp_buf))
+ {
+ /* Temporarily fake out the longjmp information until we have
+ * successfully completed this function. This only works if we have
+ * setjmp() support compiled in, but it is safe - this stuff should
+ * never happen.
+ */
+ create_struct.jmp_buf_ptr = &create_jmp_buf;
+ create_struct.jmp_buf_size = 0; /*stack allocation*/
+ create_struct.longjmp_fn = longjmp;
+# else
+ {
+# endif
+ /* Call the general version checker (shared with read and write code):
+ */
+ if (png_user_version_check(&create_struct, user_png_ver) != 0)
+ {
+ png_structrp png_ptr = png_voidcast(png_structrp,
+ png_malloc_warn(&create_struct, (sizeof *png_ptr)));
+
+ if (png_ptr != NULL)
+ {
+ /* png_ptr->zstream holds a back-pointer to the png_struct, so
+ * this can only be done now:
+ */
+ create_struct.zstream.zalloc = png_zalloc;
+ create_struct.zstream.zfree = png_zfree;
+ create_struct.zstream.opaque = png_ptr;
+
+# ifdef PNG_SETJMP_SUPPORTED
+ /* Eliminate the local error handling: */
+ create_struct.jmp_buf_ptr = NULL;
+ create_struct.jmp_buf_size = 0;
+ create_struct.longjmp_fn = 0;
+# endif
+
+ *png_ptr = create_struct;
+
+ /* This is the successful return point */
+ return png_ptr;
+ }
+ }
+ }
+
+ /* A longjmp because of a bug in the application storage allocator or a
+ * simple failure to allocate the png_struct.
+ */
+ return NULL;
+}
+
+/* Allocate the memory for an info_struct for the application. */
+PNG_FUNCTION(png_infop,PNGAPI
+png_create_info_struct,(png_const_structrp png_ptr),PNG_ALLOCATED)
+{
+ png_inforp info_ptr;
+
+ png_debug(1, "in png_create_info_struct");
+
+ if (png_ptr == NULL)
+ return NULL;
+
+ /* Use the internal API that does not (or at least should not) error out, so
+ * that this call always returns ok. The application typically sets up the
+ * error handling *after* creating the info_struct because this is the way it
+ * has always been done in 'example.c'.
+ */
+ info_ptr = png_voidcast(png_inforp, png_malloc_base(png_ptr,
+ (sizeof *info_ptr)));
+
+ if (info_ptr != NULL)
+ memset(info_ptr, 0, (sizeof *info_ptr));
+
+ return info_ptr;
+}
+
+/* This function frees the memory associated with a single info struct.
+ * Normally, one would use either png_destroy_read_struct() or
+ * png_destroy_write_struct() to free an info struct, but this may be
+ * useful for some applications. From libpng 1.6.0 this function is also used
+ * internally to implement the png_info release part of the 'struct' destroy
+ * APIs. This ensures that all possible approaches free the same data (all of
+ * it).
+ */
+void PNGAPI
+png_destroy_info_struct(png_const_structrp png_ptr, png_infopp info_ptr_ptr)
+{
+ png_inforp info_ptr = NULL;
+
+ png_debug(1, "in png_destroy_info_struct");
+
+ if (png_ptr == NULL)
+ return;
+
+ if (info_ptr_ptr != NULL)
+ info_ptr = *info_ptr_ptr;
+
+ if (info_ptr != NULL)
+ {
+ /* Do this first in case of an error below; if the app implements its own
+ * memory management this can lead to png_free calling png_error, which
+ * will abort this routine and return control to the app error handler.
+ * An infinite loop may result if it then tries to free the same info
+ * ptr.
+ */
+ *info_ptr_ptr = NULL;
+
+ png_free_data(png_ptr, info_ptr, PNG_FREE_ALL, -1);
+ memset(info_ptr, 0, (sizeof *info_ptr));
+ png_free(png_ptr, info_ptr);
+ }
+}
+
+/* Initialize the info structure. This is now an internal function (0.89)
+ * and applications using it are urged to use png_create_info_struct()
+ * instead. Use deprecated in 1.6.0, internal use removed (used internally it
+ * is just a memset).
+ *
+ * NOTE: it is almost inconceivable that this API is used because it bypasses
+ * the user-memory mechanism and the user error handling/warning mechanisms in
+ * those cases where it does anything other than a memset.
+ */
+PNG_FUNCTION(void,PNGAPI
+png_info_init_3,(png_infopp ptr_ptr, png_size_t png_info_struct_size),
+ PNG_DEPRECATED)
+{
+ png_inforp info_ptr = *ptr_ptr;
+
+ png_debug(1, "in png_info_init_3");
+
+ if (info_ptr == NULL)
+ return;
+
+ if ((sizeof (png_info)) > png_info_struct_size)
+ {
+ *ptr_ptr = NULL;
+ /* The following line is why this API should not be used: */
+ free(info_ptr);
+ info_ptr = png_voidcast(png_inforp, png_malloc_base(NULL,
+ (sizeof *info_ptr)));
+ *ptr_ptr = info_ptr;
+ }
+
+ /* Set everything to 0 */
+ memset(info_ptr, 0, (sizeof *info_ptr));
+}
+
+/* The following API is not called internally */
+void PNGAPI
+png_data_freer(png_const_structrp png_ptr, png_inforp info_ptr,
+ int freer, png_uint_32 mask)
+{
+ png_debug(1, "in png_data_freer");
+
+ if (png_ptr == NULL || info_ptr == NULL)
+ return;
+
+ if (freer == PNG_DESTROY_WILL_FREE_DATA)
+ info_ptr->free_me |= mask;
+
+ else if (freer == PNG_USER_WILL_FREE_DATA)
+ info_ptr->free_me &= ~mask;
+
+ else
+ png_error(png_ptr, "Unknown freer parameter in png_data_freer");
+}
+
+void PNGAPI
+png_free_data(png_const_structrp png_ptr, png_inforp info_ptr, png_uint_32 mask,
+ int num)
+{
+ png_debug(1, "in png_free_data");
+
+ if (png_ptr == NULL || info_ptr == NULL)
+ return;
+
+#ifdef PNG_TEXT_SUPPORTED
+ /* Free text item num or (if num == -1) all text items */
+ if (info_ptr->text != 0 &&
+ ((mask & PNG_FREE_TEXT) & info_ptr->free_me) != 0)
+ {
+ if (num != -1)
+ {
+ png_free(png_ptr, info_ptr->text[num].key);
+ info_ptr->text[num].key = NULL;
+ }
+
+ else
+ {
+ int i;
+
+ for (i = 0; i < info_ptr->num_text; i++)
+ png_free(png_ptr, info_ptr->text[i].key);
+
+ png_free(png_ptr, info_ptr->text);
+ info_ptr->text = NULL;
+ info_ptr->num_text = 0;
+ }
+ }
+#endif
+
+#ifdef PNG_tRNS_SUPPORTED
+ /* Free any tRNS entry */
+ if (((mask & PNG_FREE_TRNS) & info_ptr->free_me) != 0)
+ {
+ info_ptr->valid &= ~PNG_INFO_tRNS;
+ png_free(png_ptr, info_ptr->trans_alpha);
+ info_ptr->trans_alpha = NULL;
+ info_ptr->num_trans = 0;
+ }
+#endif
+
+#ifdef PNG_sCAL_SUPPORTED
+ /* Free any sCAL entry */
+ if (((mask & PNG_FREE_SCAL) & info_ptr->free_me) != 0)
+ {
+ png_free(png_ptr, info_ptr->scal_s_width);
+ png_free(png_ptr, info_ptr->scal_s_height);
+ info_ptr->scal_s_width = NULL;
+ info_ptr->scal_s_height = NULL;
+ info_ptr->valid &= ~PNG_INFO_sCAL;
+ }
+#endif
+
+#ifdef PNG_pCAL_SUPPORTED
+ /* Free any pCAL entry */
+ if (((mask & PNG_FREE_PCAL) & info_ptr->free_me) != 0)
+ {
+ png_free(png_ptr, info_ptr->pcal_purpose);
+ png_free(png_ptr, info_ptr->pcal_units);
+ info_ptr->pcal_purpose = NULL;
+ info_ptr->pcal_units = NULL;
+
+ if (info_ptr->pcal_params != NULL)
+ {
+ int i;
+
+ for (i = 0; i < info_ptr->pcal_nparams; i++)
+ png_free(png_ptr, info_ptr->pcal_params[i]);
+
+ png_free(png_ptr, info_ptr->pcal_params);
+ info_ptr->pcal_params = NULL;
+ }
+ info_ptr->valid &= ~PNG_INFO_pCAL;
+ }
+#endif
+
+#ifdef PNG_iCCP_SUPPORTED
+ /* Free any profile entry */
+ if (((mask & PNG_FREE_ICCP) & info_ptr->free_me) != 0)
+ {
+ png_free(png_ptr, info_ptr->iccp_name);
+ png_free(png_ptr, info_ptr->iccp_profile);
+ info_ptr->iccp_name = NULL;
+ info_ptr->iccp_profile = NULL;
+ info_ptr->valid &= ~PNG_INFO_iCCP;
+ }
+#endif
+
+#ifdef PNG_sPLT_SUPPORTED
+ /* Free a given sPLT entry, or (if num == -1) all sPLT entries */
+ if (info_ptr->splt_palettes != 0 &&
+ ((mask & PNG_FREE_SPLT) & info_ptr->free_me) != 0)
+ {
+ if (num != -1)
+ {
+ png_free(png_ptr, info_ptr->splt_palettes[num].name);
+ png_free(png_ptr, info_ptr->splt_palettes[num].entries);
+ info_ptr->splt_palettes[num].name = NULL;
+ info_ptr->splt_palettes[num].entries = NULL;
+ }
+
+ else
+ {
+ int i;
+
+ for (i = 0; i < info_ptr->splt_palettes_num; i++)
+ {
+ png_free(png_ptr, info_ptr->splt_palettes[i].name);
+ png_free(png_ptr, info_ptr->splt_palettes[i].entries);
+ }
+
+ png_free(png_ptr, info_ptr->splt_palettes);
+ info_ptr->splt_palettes = NULL;
+ info_ptr->splt_palettes_num = 0;
+ info_ptr->valid &= ~PNG_INFO_sPLT;
+ }
+ }
+#endif
+
+#ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED
+ if (info_ptr->unknown_chunks != 0 &&
+ ((mask & PNG_FREE_UNKN) & info_ptr->free_me) != 0)
+ {
+ if (num != -1)
+ {
+ png_free(png_ptr, info_ptr->unknown_chunks[num].data);
+ info_ptr->unknown_chunks[num].data = NULL;
+ }
+
+ else
+ {
+ int i;
+
+ for (i = 0; i < info_ptr->unknown_chunks_num; i++)
+ png_free(png_ptr, info_ptr->unknown_chunks[i].data);
+
+ png_free(png_ptr, info_ptr->unknown_chunks);
+ info_ptr->unknown_chunks = NULL;
+ info_ptr->unknown_chunks_num = 0;
+ }
+ }
+#endif
+
+#ifdef PNG_hIST_SUPPORTED
+ /* Free any hIST entry */
+ if (((mask & PNG_FREE_HIST) & info_ptr->free_me) != 0)
+ {
+ png_free(png_ptr, info_ptr->hist);
+ info_ptr->hist = NULL;
+ info_ptr->valid &= ~PNG_INFO_hIST;
+ }
+#endif
+
+ /* Free any PLTE entry that was internally allocated */
+ if (((mask & PNG_FREE_PLTE) & info_ptr->free_me) != 0)
+ {
+ png_free(png_ptr, info_ptr->palette);
+ info_ptr->palette = NULL;
+ info_ptr->valid &= ~PNG_INFO_PLTE;
+ info_ptr->num_palette = 0;
+ }
+
+#ifdef PNG_INFO_IMAGE_SUPPORTED
+ /* Free any image bits attached to the info structure */
+ if (((mask & PNG_FREE_ROWS) & info_ptr->free_me) != 0)
+ {
+ if (info_ptr->row_pointers != 0)
+ {
+ png_uint_32 row;
+ for (row = 0; row < info_ptr->height; row++)
+ png_free(png_ptr, info_ptr->row_pointers[row]);
+
+ png_free(png_ptr, info_ptr->row_pointers);
+ info_ptr->row_pointers = NULL;
+ }
+ info_ptr->valid &= ~PNG_INFO_IDAT;
+ }
+#endif
+
+ if (num != -1)
+ mask &= ~PNG_FREE_MUL;
+
+ info_ptr->free_me &= ~mask;
+}
+#endif /* READ || WRITE */
+
+/* This function returns a pointer to the io_ptr associated with the user
+ * functions. The application should free any memory associated with this
+ * pointer before png_write_destroy() or png_read_destroy() are called.
+ */
+png_voidp PNGAPI
+png_get_io_ptr(png_const_structrp png_ptr)
+{
+ if (png_ptr == NULL)
+ return (NULL);
+
+ return (png_ptr->io_ptr);
+}
+
+#if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
+# ifdef PNG_STDIO_SUPPORTED
+/* Initialize the default input/output functions for the PNG file. If you
+ * use your own read or write routines, you can call either png_set_read_fn()
+ * or png_set_write_fn() instead of png_init_io(). If you have defined
+ * PNG_NO_STDIO or otherwise disabled PNG_STDIO_SUPPORTED, you must use a
+ * function of your own because "FILE *" isn't necessarily available.
+ */
+void PNGAPI
+png_init_io(png_structrp png_ptr, png_FILE_p fp)
+{
+ png_debug(1, "in png_init_io");
+
+ if (png_ptr == NULL)
+ return;
+
+ png_ptr->io_ptr = (png_voidp)fp;
+}
+# endif
+
+# ifdef PNG_SAVE_INT_32_SUPPORTED
+/* The png_save_int_32 function assumes integers are stored in two's
+ * complement format. If this isn't the case, then this routine needs to
+ * be modified to write data in two's complement format. Note that,
+ * the following works correctly even if png_int_32 has more than 32 bits
+ * (compare the more complex code required on read for sign extension.)
+ */
+void PNGAPI
+png_save_int_32(png_bytep buf, png_int_32 i)
+{
+ buf[0] = (png_byte)((i >> 24) & 0xff);
+ buf[1] = (png_byte)((i >> 16) & 0xff);
+ buf[2] = (png_byte)((i >> 8) & 0xff);
+ buf[3] = (png_byte)(i & 0xff);
+}
+# endif
+
+# ifdef PNG_TIME_RFC1123_SUPPORTED
+/* Convert the supplied time into an RFC 1123 string suitable for use in
+ * a "Creation Time" or other text-based time string.
+ */
+int PNGAPI
+png_convert_to_rfc1123_buffer(char out[29], png_const_timep ptime)
+{
+ static PNG_CONST char short_months[12][4] =
+ {"Jan", "Feb", "Mar", "Apr", "May", "Jun",
+ "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"};
+
+ if (out == NULL)
+ return 0;
+
+ if (ptime->year > 9999 /* RFC1123 limitation */ ||
+ ptime->month == 0 || ptime->month > 12 ||
+ ptime->day == 0 || ptime->day > 31 ||
+ ptime->hour > 23 || ptime->minute > 59 ||
+ ptime->second > 60)
+ return 0;
+
+ {
+ size_t pos = 0;
+ char number_buf[5]; /* enough for a four-digit year */
+
+# define APPEND_STRING(string) pos = png_safecat(out, 29, pos, (string))
+# define APPEND_NUMBER(format, value)\
+ APPEND_STRING(PNG_FORMAT_NUMBER(number_buf, format, (value)))
+# define APPEND(ch) if (pos < 28) out[pos++] = (ch)
+
+ APPEND_NUMBER(PNG_NUMBER_FORMAT_u, (unsigned)ptime->day);
+ APPEND(' ');
+ APPEND_STRING(short_months[(ptime->month - 1)]);
+ APPEND(' ');
+ APPEND_NUMBER(PNG_NUMBER_FORMAT_u, ptime->year);
+ APPEND(' ');
+ APPEND_NUMBER(PNG_NUMBER_FORMAT_02u, (unsigned)ptime->hour);
+ APPEND(':');
+ APPEND_NUMBER(PNG_NUMBER_FORMAT_02u, (unsigned)ptime->minute);
+ APPEND(':');
+ APPEND_NUMBER(PNG_NUMBER_FORMAT_02u, (unsigned)ptime->second);
+ APPEND_STRING(" +0000"); /* This reliably terminates the buffer */
+
+# undef APPEND
+# undef APPEND_NUMBER
+# undef APPEND_STRING
+ }
+
+ return 1;
+}
+
+# if PNG_LIBPNG_VER < 10700
+/* To do: remove the following from libpng-1.7 */
+/* Original API that uses a private buffer in png_struct.
+ * Deprecated because it causes png_struct to carry a spurious temporary
+ * buffer (png_struct::time_buffer), better to have the caller pass this in.
+ */
+png_const_charp PNGAPI
+png_convert_to_rfc1123(png_structrp png_ptr, png_const_timep ptime)
+{
+ if (png_ptr != NULL)
+ {
+ /* The only failure above if png_ptr != NULL is from an invalid ptime */
+ if (png_convert_to_rfc1123_buffer(png_ptr->time_buffer, ptime) == 0)
+ png_warning(png_ptr, "Ignoring invalid time value");
+
+ else
+ return png_ptr->time_buffer;
+ }
+
+ return NULL;
+}
+# endif /* LIBPNG_VER < 10700 */
+# endif /* TIME_RFC1123 */
+
+#endif /* READ || WRITE */
+
+png_const_charp PNGAPI
+png_get_copyright(png_const_structrp png_ptr)
+{
+ PNG_UNUSED(png_ptr) /* Silence compiler warning about unused png_ptr */
+#ifdef PNG_STRING_COPYRIGHT
+ return PNG_STRING_COPYRIGHT
+#else
+# ifdef __STDC__
+ return PNG_STRING_NEWLINE \
+ "libpng version 1.6.17 - March 26, 2015" PNG_STRING_NEWLINE \
+ "Copyright (c) 1998-2015 Glenn Randers-Pehrson" PNG_STRING_NEWLINE \
+ "Copyright (c) 1996-1997 Andreas Dilger" PNG_STRING_NEWLINE \
+ "Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc." \
+ PNG_STRING_NEWLINE;
+# else
+ return "libpng version 1.6.17 - March 26, 2015\
+ Copyright (c) 1998-2015 Glenn Randers-Pehrson\
+ Copyright (c) 1996-1997 Andreas Dilger\
+ Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.";
+# endif
+#endif
+}
+
+/* The following return the library version as a short string in the
+ * format 1.0.0 through 99.99.99zz. To get the version of *.h files
+ * used with your application, print out PNG_LIBPNG_VER_STRING, which
+ * is defined in png.h.
+ * Note: now there is no difference between png_get_libpng_ver() and
+ * png_get_header_ver(). Due to the version_nn_nn_nn typedef guard,
+ * it is guaranteed that png.c uses the correct version of png.h.
+ */
+png_const_charp PNGAPI
+png_get_libpng_ver(png_const_structrp png_ptr)
+{
+ /* Version of *.c files used when building libpng */
+ return png_get_header_ver(png_ptr);
+}
+
+png_const_charp PNGAPI
+png_get_header_ver(png_const_structrp png_ptr)
+{
+ /* Version of *.h files used when building libpng */
+ PNG_UNUSED(png_ptr) /* Silence compiler warning about unused png_ptr */
+ return PNG_LIBPNG_VER_STRING;
+}
+
+png_const_charp PNGAPI
+png_get_header_version(png_const_structrp png_ptr)
+{
+ /* Returns longer string containing both version and date */
+ PNG_UNUSED(png_ptr) /* Silence compiler warning about unused png_ptr */
+#ifdef __STDC__
+ return PNG_HEADER_VERSION_STRING
+# ifndef PNG_READ_SUPPORTED
+ " (NO READ SUPPORT)"
+# endif
+ PNG_STRING_NEWLINE;
+#else
+ return PNG_HEADER_VERSION_STRING;
+#endif
+}
+
+#ifdef PNG_BUILD_GRAYSCALE_PALETTE_SUPPORTED
+/* NOTE: this routine is not used internally! */
+/* Build a grayscale palette. Palette is assumed to be 1 << bit_depth
+ * large of png_color. This lets grayscale images be treated as
+ * paletted. Most useful for gamma correction and simplification
+ * of code. This API is not used internally.
+ */
+void PNGAPI
+png_build_grayscale_palette(int bit_depth, png_colorp palette)
+{
+ int num_palette;
+ int color_inc;
+ int i;
+ int v;
+
+ png_debug(1, "in png_do_build_grayscale_palette");
+
+ if (palette == NULL)
+ return;
+
+ switch (bit_depth)
+ {
+ case 1:
+ num_palette = 2;
+ color_inc = 0xff;
+ break;
+
+ case 2:
+ num_palette = 4;
+ color_inc = 0x55;
+ break;
+
+ case 4:
+ num_palette = 16;
+ color_inc = 0x11;
+ break;
+
+ case 8:
+ num_palette = 256;
+ color_inc = 1;
+ break;
+
+ default:
+ num_palette = 0;
+ color_inc = 0;
+ break;
+ }
+
+ for (i = 0, v = 0; i < num_palette; i++, v += color_inc)
+ {
+ palette[i].red = (png_byte)(v & 0xff);
+ palette[i].green = (png_byte)(v & 0xff);
+ palette[i].blue = (png_byte)(v & 0xff);
+ }
+}
+#endif
+
+#ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
+int PNGAPI
+png_handle_as_unknown(png_const_structrp png_ptr, png_const_bytep chunk_name)
+{
+ /* Check chunk_name and return "keep" value if it's on the list, else 0 */
+ png_const_bytep p, p_end;
+
+ if (png_ptr == NULL || chunk_name == NULL || png_ptr->num_chunk_list == 0)
+ return PNG_HANDLE_CHUNK_AS_DEFAULT;
+
+ p_end = png_ptr->chunk_list;
+ p = p_end + png_ptr->num_chunk_list*5; /* beyond end */
+
+ /* The code is the fifth byte after each four byte string. Historically this
+ * code was always searched from the end of the list, this is no longer
+ * necessary because the 'set' routine handles duplicate entries correcty.
+ */
+ do /* num_chunk_list > 0, so at least one */
+ {
+ p -= 5;
+
+ if (memcmp(chunk_name, p, 4) == 0)
+ return p[4];
+ }
+ while (p > p_end);
+
+ /* This means that known chunks should be processed and unknown chunks should
+ * be handled according to the value of png_ptr->unknown_default; this can be
+ * confusing because, as a result, there are two levels of defaulting for
+ * unknown chunks.
+ */
+ return PNG_HANDLE_CHUNK_AS_DEFAULT;
+}
+
+#if defined(PNG_READ_UNKNOWN_CHUNKS_SUPPORTED) ||\
+ defined(PNG_HANDLE_AS_UNKNOWN_SUPPORTED)
+int /* PRIVATE */
+png_chunk_unknown_handling(png_const_structrp png_ptr, png_uint_32 chunk_name)
+{
+ png_byte chunk_string[5];
+
+ PNG_CSTRING_FROM_CHUNK(chunk_string, chunk_name);
+ return png_handle_as_unknown(png_ptr, chunk_string);
+}
+#endif /* READ_UNKNOWN_CHUNKS || HANDLE_AS_UNKNOWN */
+#endif /* SET_UNKNOWN_CHUNKS */
+
+#ifdef PNG_READ_SUPPORTED
+/* This function, added to libpng-1.0.6g, is untested. */
+int PNGAPI
+png_reset_zstream(png_structrp png_ptr)
+{
+ if (png_ptr == NULL)
+ return Z_STREAM_ERROR;
+
+ /* WARNING: this resets the window bits to the maximum! */
+ return (inflateReset(&png_ptr->zstream));
+}
+#endif /* READ */
+
+/* This function was added to libpng-1.0.7 */
+png_uint_32 PNGAPI
+png_access_version_number(void)
+{
+ /* Version of *.c files used when building libpng */
+ return((png_uint_32)PNG_LIBPNG_VER);
+}
+
+#if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
+/* Ensure that png_ptr->zstream.msg holds some appropriate error message string.
+ * If it doesn't 'ret' is used to set it to something appropriate, even in cases
+ * like Z_OK or Z_STREAM_END where the error code is apparently a success code.
+ */
+void /* PRIVATE */
+png_zstream_error(png_structrp png_ptr, int ret)
+{
+ /* Translate 'ret' into an appropriate error string, priority is given to the
+ * one in zstream if set. This always returns a string, even in cases like
+ * Z_OK or Z_STREAM_END where the error code is a success code.
+ */
+ if (png_ptr->zstream.msg == NULL) switch (ret)
+ {
+ default:
+ case Z_OK:
+ png_ptr->zstream.msg = PNGZ_MSG_CAST("unexpected zlib return code");
+ break;
+
+ case Z_STREAM_END:
+ /* Normal exit */
+ png_ptr->zstream.msg = PNGZ_MSG_CAST("unexpected end of LZ stream");
+ break;
+
+ case Z_NEED_DICT:
+ /* This means the deflate stream did not have a dictionary; this
+ * indicates a bogus PNG.
+ */
+ png_ptr->zstream.msg = PNGZ_MSG_CAST("missing LZ dictionary");
+ break;
+
+ case Z_ERRNO:
+ /* gz APIs only: should not happen */
+ png_ptr->zstream.msg = PNGZ_MSG_CAST("zlib IO error");
+ break;
+
+ case Z_STREAM_ERROR:
+ /* internal libpng error */
+ png_ptr->zstream.msg = PNGZ_MSG_CAST("bad parameters to zlib");
+ break;
+
+ case Z_DATA_ERROR:
+ png_ptr->zstream.msg = PNGZ_MSG_CAST("damaged LZ stream");
+ break;
+
+ case Z_MEM_ERROR:
+ png_ptr->zstream.msg = PNGZ_MSG_CAST("insufficient memory");
+ break;
+
+ case Z_BUF_ERROR:
+ /* End of input or output; not a problem if the caller is doing
+ * incremental read or write.
+ */
+ png_ptr->zstream.msg = PNGZ_MSG_CAST("truncated");
+ break;
+
+ case Z_VERSION_ERROR:
+ png_ptr->zstream.msg = PNGZ_MSG_CAST("unsupported zlib version");
+ break;
+
+ case PNG_UNEXPECTED_ZLIB_RETURN:
+ /* Compile errors here mean that zlib now uses the value co-opted in
+ * pngpriv.h for PNG_UNEXPECTED_ZLIB_RETURN; update the switch above
+ * and change pngpriv.h. Note that this message is "... return",
+ * whereas the default/Z_OK one is "... return code".
+ */
+ png_ptr->zstream.msg = PNGZ_MSG_CAST("unexpected zlib return");
+ break;
+ }
+}
+
+/* png_convert_size: a PNGAPI but no longer in png.h, so deleted
+ * at libpng 1.5.5!
+ */
+
+/* Added at libpng version 1.2.34 and 1.4.0 (moved from pngset.c) */
+#ifdef PNG_GAMMA_SUPPORTED /* always set if COLORSPACE */
+static int
+png_colorspace_check_gamma(png_const_structrp png_ptr,
+ png_colorspacerp colorspace, png_fixed_point gAMA, int from)
+ /* This is called to check a new gamma value against an existing one. The
+ * routine returns false if the new gamma value should not be written.
+ *
+ * 'from' says where the new gamma value comes from:
+ *
+ * 0: the new gamma value is the libpng estimate for an ICC profile
+ * 1: the new gamma value comes from a gAMA chunk
+ * 2: the new gamma value comes from an sRGB chunk
+ */
+{
+ png_fixed_point gtest;
+
+ if ((colorspace->flags & PNG_COLORSPACE_HAVE_GAMMA) != 0 &&
+ (png_muldiv(>est, colorspace->gamma, PNG_FP_1, gAMA) == 0 ||
+ png_gamma_significant(gtest) != 0))
+ {
+ /* Either this is an sRGB image, in which case the calculated gamma
+ * approximation should match, or this is an image with a profile and the
+ * value libpng calculates for the gamma of the profile does not match the
+ * value recorded in the file. The former, sRGB, case is an error, the
+ * latter is just a warning.
+ */
+ if ((colorspace->flags & PNG_COLORSPACE_FROM_sRGB) != 0 || from == 2)
+ {
+ png_chunk_report(png_ptr, "gamma value does not match sRGB",
+ PNG_CHUNK_ERROR);
+ /* Do not overwrite an sRGB value */
+ return from == 2;
+ }
+
+ else /* sRGB tag not involved */
+ {
+ png_chunk_report(png_ptr, "gamma value does not match libpng estimate",
+ PNG_CHUNK_WARNING);
+ return from == 1;
+ }
+ }
+
+ return 1;
+}
+
+void /* PRIVATE */
+png_colorspace_set_gamma(png_const_structrp png_ptr,
+ png_colorspacerp colorspace, png_fixed_point gAMA)
+{
+ /* Changed in libpng-1.5.4 to limit the values to ensure overflow can't
+ * occur. Since the fixed point representation is asymetrical it is
+ * possible for 1/gamma to overflow the limit of 21474 and this means the
+ * gamma value must be at least 5/100000 and hence at most 20000.0. For
+ * safety the limits here are a little narrower. The values are 0.00016 to
+ * 6250.0, which are truly ridiculous gamma values (and will produce
+ * displays that are all black or all white.)
+ *
+ * In 1.6.0 this test replaces the ones in pngrutil.c, in the gAMA chunk
+ * handling code, which only required the value to be >0.
+ */
+ png_const_charp errmsg;
+
+ if (gAMA < 16 || gAMA > 625000000)
+ errmsg = "gamma value out of range";
+
+# ifdef PNG_READ_gAMA_SUPPORTED
+ /* Allow the application to set the gamma value more than once */
+ else if ((png_ptr->mode & PNG_IS_READ_STRUCT) != 0 &&
+ (colorspace->flags & PNG_COLORSPACE_FROM_gAMA) != 0)
+ errmsg = "duplicate";
+# endif
+
+ /* Do nothing if the colorspace is already invalid */
+ else if ((colorspace->flags & PNG_COLORSPACE_INVALID) != 0)
+ return;
+
+ else
+ {
+ if (png_colorspace_check_gamma(png_ptr, colorspace, gAMA,
+ 1/*from gAMA*/) != 0)
+ {
+ /* Store this gamma value. */
+ colorspace->gamma = gAMA;
+ colorspace->flags |=
+ (PNG_COLORSPACE_HAVE_GAMMA | PNG_COLORSPACE_FROM_gAMA);
+ }
+
+ /* At present if the check_gamma test fails the gamma of the colorspace is
+ * not updated however the colorspace is not invalidated. This
+ * corresponds to the case where the existing gamma comes from an sRGB
+ * chunk or profile. An error message has already been output.
+ */
+ return;
+ }
+
+ /* Error exit - errmsg has been set. */
+ colorspace->flags |= PNG_COLORSPACE_INVALID;
+ png_chunk_report(png_ptr, errmsg, PNG_CHUNK_WRITE_ERROR);
+}
+
+void /* PRIVATE */
+png_colorspace_sync_info(png_const_structrp png_ptr, png_inforp info_ptr)
+{
+ if ((info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) != 0)
+ {
+ /* Everything is invalid */
+ info_ptr->valid &= ~(PNG_INFO_gAMA|PNG_INFO_cHRM|PNG_INFO_sRGB|
+ PNG_INFO_iCCP);
+
+# ifdef PNG_COLORSPACE_SUPPORTED
+ /* Clean up the iCCP profile now if it won't be used. */
+ png_free_data(png_ptr, info_ptr, PNG_FREE_ICCP, -1/*not used*/);
+# else
+ PNG_UNUSED(png_ptr)
+# endif
+ }
+
+ else
+ {
+# ifdef PNG_COLORSPACE_SUPPORTED
+ /* Leave the INFO_iCCP flag set if the pngset.c code has already set
+ * it; this allows a PNG to contain a profile which matches sRGB and
+ * yet still have that profile retrievable by the application.
+ */
+ if ((info_ptr->colorspace.flags & PNG_COLORSPACE_MATCHES_sRGB) != 0)
+ info_ptr->valid |= PNG_INFO_sRGB;
+
+ else
+ info_ptr->valid &= ~PNG_INFO_sRGB;
+
+ if ((info_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_ENDPOINTS) != 0)
+ info_ptr->valid |= PNG_INFO_cHRM;
+
+ else
+ info_ptr->valid &= ~PNG_INFO_cHRM;
+# endif
+
+ if ((info_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_GAMMA) != 0)
+ info_ptr->valid |= PNG_INFO_gAMA;
+
+ else
+ info_ptr->valid &= ~PNG_INFO_gAMA;
+ }
+}
+
+#ifdef PNG_READ_SUPPORTED
+void /* PRIVATE */
+png_colorspace_sync(png_const_structrp png_ptr, png_inforp info_ptr)
+{
+ if (info_ptr == NULL) /* reduce code size; check here not in the caller */
+ return;
+
+ info_ptr->colorspace = png_ptr->colorspace;
+ png_colorspace_sync_info(png_ptr, info_ptr);
+}
+#endif
+#endif /* GAMMA */
+
+#ifdef PNG_COLORSPACE_SUPPORTED
+/* Added at libpng-1.5.5 to support read and write of true CIEXYZ values for
+ * cHRM, as opposed to using chromaticities. These internal APIs return
+ * non-zero on a parameter error. The X, Y and Z values are required to be
+ * positive and less than 1.0.
+ */
+static int
+png_xy_from_XYZ(png_xy *xy, const png_XYZ *XYZ)
+{
+ png_int_32 d, dwhite, whiteX, whiteY;
+
+ d = XYZ->red_X + XYZ->red_Y + XYZ->red_Z;
+ if (png_muldiv(&xy->redx, XYZ->red_X, PNG_FP_1, d) == 0)
+ return 1;
+ if (png_muldiv(&xy->redy, XYZ->red_Y, PNG_FP_1, d) == 0)
+ return 1;
+ dwhite = d;
+ whiteX = XYZ->red_X;
+ whiteY = XYZ->red_Y;
+
+ d = XYZ->green_X + XYZ->green_Y + XYZ->green_Z;
+ if (png_muldiv(&xy->greenx, XYZ->green_X, PNG_FP_1, d) == 0)
+ return 1;
+ if (png_muldiv(&xy->greeny, XYZ->green_Y, PNG_FP_1, d) == 0)
+ return 1;
+ dwhite += d;
+ whiteX += XYZ->green_X;
+ whiteY += XYZ->green_Y;
+
+ d = XYZ->blue_X + XYZ->blue_Y + XYZ->blue_Z;
+ if (png_muldiv(&xy->bluex, XYZ->blue_X, PNG_FP_1, d) == 0)
+ return 1;
+ if (png_muldiv(&xy->bluey, XYZ->blue_Y, PNG_FP_1, d) == 0)
+ return 1;
+ dwhite += d;
+ whiteX += XYZ->blue_X;
+ whiteY += XYZ->blue_Y;
+
+ /* The reference white is simply the sum of the end-point (X,Y,Z) vectors,
+ * thus:
+ */
+ if (png_muldiv(&xy->whitex, whiteX, PNG_FP_1, dwhite) == 0)
+ return 1;
+ if (png_muldiv(&xy->whitey, whiteY, PNG_FP_1, dwhite) == 0)
+ return 1;
+
+ return 0;
+}
+
+static int
+png_XYZ_from_xy(png_XYZ *XYZ, const png_xy *xy)
+{
+ png_fixed_point red_inverse, green_inverse, blue_scale;
+ png_fixed_point left, right, denominator;
+
+ /* Check xy and, implicitly, z. Note that wide gamut color spaces typically
+ * have end points with 0 tristimulus values (these are impossible end
+ * points, but they are used to cover the possible colors.)
+ */
+ if (xy->redx < 0 || xy->redx > PNG_FP_1) return 1;
+ if (xy->redy < 0 || xy->redy > PNG_FP_1-xy->redx) return 1;
+ if (xy->greenx < 0 || xy->greenx > PNG_FP_1) return 1;
+ if (xy->greeny < 0 || xy->greeny > PNG_FP_1-xy->greenx) return 1;
+ if (xy->bluex < 0 || xy->bluex > PNG_FP_1) return 1;
+ if (xy->bluey < 0 || xy->bluey > PNG_FP_1-xy->bluex) return 1;
+ if (xy->whitex < 0 || xy->whitex > PNG_FP_1) return 1;
+ if (xy->whitey < 0 || xy->whitey > PNG_FP_1-xy->whitex) return 1;
+
+ /* The reverse calculation is more difficult because the original tristimulus
+ * value had 9 independent values (red,green,blue)x(X,Y,Z) however only 8
+ * derived values were recorded in the cHRM chunk;
+ * (red,green,blue,white)x(x,y). This loses one degree of freedom and
+ * therefore an arbitrary ninth value has to be introduced to undo the
+ * original transformations.
+ *
+ * Think of the original end-points as points in (X,Y,Z) space. The
+ * chromaticity values (c) have the property:
+ *
+ * C
+ * c = ---------
+ * X + Y + Z
+ *
+ * For each c (x,y,z) from the corresponding original C (X,Y,Z). Thus the
+ * three chromaticity values (x,y,z) for each end-point obey the
+ * relationship:
+ *
+ * x + y + z = 1
+ *
+ * This describes the plane in (X,Y,Z) space that intersects each axis at the
+ * value 1.0; call this the chromaticity plane. Thus the chromaticity
+ * calculation has scaled each end-point so that it is on the x+y+z=1 plane
+ * and chromaticity is the intersection of the vector from the origin to the
+ * (X,Y,Z) value with the chromaticity plane.
+ *
+ * To fully invert the chromaticity calculation we would need the three
+ * end-point scale factors, (red-scale, green-scale, blue-scale), but these
+ * were not recorded. Instead we calculated the reference white (X,Y,Z) and
+ * recorded the chromaticity of this. The reference white (X,Y,Z) would have
+ * given all three of the scale factors since:
+ *
+ * color-C = color-c * color-scale
+ * white-C = red-C + green-C + blue-C
+ * = red-c*red-scale + green-c*green-scale + blue-c*blue-scale
+ *
+ * But cHRM records only white-x and white-y, so we have lost the white scale
+ * factor:
+ *
+ * white-C = white-c*white-scale
+ *
+ * To handle this the inverse transformation makes an arbitrary assumption
+ * about white-scale:
+ *
+ * Assume: white-Y = 1.0
+ * Hence: white-scale = 1/white-y
+ * Or: red-Y + green-Y + blue-Y = 1.0
+ *
+ * Notice the last statement of the assumption gives an equation in three of
+ * the nine values we want to calculate. 8 more equations come from the
+ * above routine as summarised at the top above (the chromaticity
+ * calculation):
+ *
+ * Given: color-x = color-X / (color-X + color-Y + color-Z)
+ * Hence: (color-x - 1)*color-X + color.x*color-Y + color.x*color-Z = 0
+ *
+ * This is 9 simultaneous equations in the 9 variables "color-C" and can be
+ * solved by Cramer's rule. Cramer's rule requires calculating 10 9x9 matrix
+ * determinants, however this is not as bad as it seems because only 28 of
+ * the total of 90 terms in the various matrices are non-zero. Nevertheless
+ * Cramer's rule is notoriously numerically unstable because the determinant
+ * calculation involves the difference of large, but similar, numbers. It is
+ * difficult to be sure that the calculation is stable for real world values
+ * and it is certain that it becomes unstable where the end points are close
+ * together.
+ *
+ * So this code uses the perhaps slightly less optimal but more
+ * understandable and totally obvious approach of calculating color-scale.
+ *
+ * This algorithm depends on the precision in white-scale and that is
+ * (1/white-y), so we can immediately see that as white-y approaches 0 the
+ * accuracy inherent in the cHRM chunk drops off substantially.
+ *
+ * libpng arithmetic: a simple inversion of the above equations
+ * ------------------------------------------------------------
+ *
+ * white_scale = 1/white-y
+ * white-X = white-x * white-scale
+ * white-Y = 1.0
+ * white-Z = (1 - white-x - white-y) * white_scale
+ *
+ * white-C = red-C + green-C + blue-C
+ * = red-c*red-scale + green-c*green-scale + blue-c*blue-scale
+ *
+ * This gives us three equations in (red-scale,green-scale,blue-scale) where
+ * all the coefficients are now known:
+ *
+ * red-x*red-scale + green-x*green-scale + blue-x*blue-scale
+ * = white-x/white-y
+ * red-y*red-scale + green-y*green-scale + blue-y*blue-scale = 1
+ * red-z*red-scale + green-z*green-scale + blue-z*blue-scale
+ * = (1 - white-x - white-y)/white-y
+ *
+ * In the last equation color-z is (1 - color-x - color-y) so we can add all
+ * three equations together to get an alternative third:
+ *
+ * red-scale + green-scale + blue-scale = 1/white-y = white-scale
+ *
+ * So now we have a Cramer's rule solution where the determinants are just
+ * 3x3 - far more tractible. Unfortunately 3x3 determinants still involve
+ * multiplication of three coefficients so we can't guarantee to avoid
+ * overflow in the libpng fixed point representation. Using Cramer's rule in
+ * floating point is probably a good choice here, but it's not an option for
+ * fixed point. Instead proceed to simplify the first two equations by
+ * eliminating what is likely to be the largest value, blue-scale:
+ *
+ * blue-scale = white-scale - red-scale - green-scale
+ *
+ * Hence:
+ *
+ * (red-x - blue-x)*red-scale + (green-x - blue-x)*green-scale =
+ * (white-x - blue-x)*white-scale
+ *
+ * (red-y - blue-y)*red-scale + (green-y - blue-y)*green-scale =
+ * 1 - blue-y*white-scale
+ *
+ * And now we can trivially solve for (red-scale,green-scale):
+ *
+ * green-scale =
+ * (white-x - blue-x)*white-scale - (red-x - blue-x)*red-scale
+ * -----------------------------------------------------------
+ * green-x - blue-x
+ *
+ * red-scale =
+ * 1 - blue-y*white-scale - (green-y - blue-y) * green-scale
+ * ---------------------------------------------------------
+ * red-y - blue-y
+ *
+ * Hence:
+ *
+ * red-scale =
+ * ( (green-x - blue-x) * (white-y - blue-y) -
+ * (green-y - blue-y) * (white-x - blue-x) ) / white-y
+ * -------------------------------------------------------------------------
+ * (green-x - blue-x)*(red-y - blue-y)-(green-y - blue-y)*(red-x - blue-x)
+ *
+ * green-scale =
+ * ( (red-y - blue-y) * (white-x - blue-x) -
+ * (red-x - blue-x) * (white-y - blue-y) ) / white-y
+ * -------------------------------------------------------------------------
+ * (green-x - blue-x)*(red-y - blue-y)-(green-y - blue-y)*(red-x - blue-x)
+ *
+ * Accuracy:
+ * The input values have 5 decimal digits of accuracy. The values are all in
+ * the range 0 < value < 1, so simple products are in the same range but may
+ * need up to 10 decimal digits to preserve the original precision and avoid
+ * underflow. Because we are using a 32-bit signed representation we cannot
+ * match this; the best is a little over 9 decimal digits, less than 10.
+ *
+ * The approach used here is to preserve the maximum precision within the
+ * signed representation. Because the red-scale calculation above uses the
+ * difference between two products of values that must be in the range -1..+1
+ * it is sufficient to divide the product by 7; ceil(100,000/32767*2). The
+ * factor is irrelevant in the calculation because it is applied to both
+ * numerator and denominator.
+ *
+ * Note that the values of the differences of the products of the
+ * chromaticities in the above equations tend to be small, for example for
+ * the sRGB chromaticities they are:
+ *
+ * red numerator: -0.04751
+ * green numerator: -0.08788
+ * denominator: -0.2241 (without white-y multiplication)
+ *
+ * The resultant Y coefficients from the chromaticities of some widely used
+ * color space definitions are (to 15 decimal places):
+ *
+ * sRGB
+ * 0.212639005871510 0.715168678767756 0.072192315360734
+ * Kodak ProPhoto
+ * 0.288071128229293 0.711843217810102 0.000085653960605
+ * Adobe RGB
+ * 0.297344975250536 0.627363566255466 0.075291458493998
+ * Adobe Wide Gamut RGB
+ * 0.258728243040113 0.724682314948566 0.016589442011321
+ */
+ /* By the argument, above overflow should be impossible here. The return
+ * value of 2 indicates an internal error to the caller.
+ */
+ if (png_muldiv(&left, xy->greenx-xy->bluex, xy->redy - xy->bluey, 7) == 0)
+ return 2;
+ if (png_muldiv(&right, xy->greeny-xy->bluey, xy->redx - xy->bluex, 7) == 0)
+ return 2;
+ denominator = left - right;
+
+ /* Now find the red numerator. */
+ if (png_muldiv(&left, xy->greenx-xy->bluex, xy->whitey-xy->bluey, 7) == 0)
+ return 2;
+ if (png_muldiv(&right, xy->greeny-xy->bluey, xy->whitex-xy->bluex, 7) == 0)
+ return 2;
+
+ /* Overflow is possible here and it indicates an extreme set of PNG cHRM
+ * chunk values. This calculation actually returns the reciprocal of the
+ * scale value because this allows us to delay the multiplication of white-y
+ * into the denominator, which tends to produce a small number.
+ */
+ if (png_muldiv(&red_inverse, xy->whitey, denominator, left-right) == 0 ||
+ red_inverse <= xy->whitey /* r+g+b scales = white scale */)
+ return 1;
+
+ /* Similarly for green_inverse: */
+ if (png_muldiv(&left, xy->redy-xy->bluey, xy->whitex-xy->bluex, 7) == 0)
+ return 2;
+ if (png_muldiv(&right, xy->redx-xy->bluex, xy->whitey-xy->bluey, 7) == 0)
+ return 2;
+ if (png_muldiv(&green_inverse, xy->whitey, denominator, left-right) == 0 ||
+ green_inverse <= xy->whitey)
+ return 1;
+
+ /* And the blue scale, the checks above guarantee this can't overflow but it
+ * can still produce 0 for extreme cHRM values.
+ */
+ blue_scale = png_reciprocal(xy->whitey) - png_reciprocal(red_inverse) -
+ png_reciprocal(green_inverse);
+ if (blue_scale <= 0)
+ return 1;
+
+
+ /* And fill in the png_XYZ: */
+ if (png_muldiv(&XYZ->red_X, xy->redx, PNG_FP_1, red_inverse) == 0)
+ return 1;
+ if (png_muldiv(&XYZ->red_Y, xy->redy, PNG_FP_1, red_inverse) == 0)
+ return 1;
+ if (png_muldiv(&XYZ->red_Z, PNG_FP_1 - xy->redx - xy->redy, PNG_FP_1,
+ red_inverse) == 0)
+ return 1;
+
+ if (png_muldiv(&XYZ->green_X, xy->greenx, PNG_FP_1, green_inverse) == 0)
+ return 1;
+ if (png_muldiv(&XYZ->green_Y, xy->greeny, PNG_FP_1, green_inverse) == 0)
+ return 1;
+ if (png_muldiv(&XYZ->green_Z, PNG_FP_1 - xy->greenx - xy->greeny, PNG_FP_1,
+ green_inverse) == 0)
+ return 1;
+
+ if (png_muldiv(&XYZ->blue_X, xy->bluex, blue_scale, PNG_FP_1) == 0)
+ return 1;
+ if (png_muldiv(&XYZ->blue_Y, xy->bluey, blue_scale, PNG_FP_1) == 0)
+ return 1;
+ if (png_muldiv(&XYZ->blue_Z, PNG_FP_1 - xy->bluex - xy->bluey, blue_scale,
+ PNG_FP_1) == 0)
+ return 1;
+
+ return 0; /*success*/
+}
+
+static int
+png_XYZ_normalize(png_XYZ *XYZ)
+{
+ png_int_32 Y;
+
+ if (XYZ->red_Y < 0 || XYZ->green_Y < 0 || XYZ->blue_Y < 0 ||
+ XYZ->red_X < 0 || XYZ->green_X < 0 || XYZ->blue_X < 0 ||
+ XYZ->red_Z < 0 || XYZ->green_Z < 0 || XYZ->blue_Z < 0)
+ return 1;
+
+ /* Normalize by scaling so the sum of the end-point Y values is PNG_FP_1.
+ * IMPLEMENTATION NOTE: ANSI requires signed overflow not to occur, therefore
+ * relying on addition of two positive values producing a negative one is not
+ * safe.
+ */
+ Y = XYZ->red_Y;
+ if (0x7fffffff - Y < XYZ->green_X)
+ return 1;
+ Y += XYZ->green_Y;
+ if (0x7fffffff - Y < XYZ->blue_X)
+ return 1;
+ Y += XYZ->blue_Y;
+
+ if (Y != PNG_FP_1)
+ {
+ if (png_muldiv(&XYZ->red_X, XYZ->red_X, PNG_FP_1, Y) == 0)
+ return 1;
+ if (png_muldiv(&XYZ->red_Y, XYZ->red_Y, PNG_FP_1, Y) == 0)
+ return 1;
+ if (png_muldiv(&XYZ->red_Z, XYZ->red_Z, PNG_FP_1, Y) == 0)
+ return 1;
+
+ if (png_muldiv(&XYZ->green_X, XYZ->green_X, PNG_FP_1, Y) == 0)
+ return 1;
+ if (png_muldiv(&XYZ->green_Y, XYZ->green_Y, PNG_FP_1, Y) == 0)
+ return 1;
+ if (png_muldiv(&XYZ->green_Z, XYZ->green_Z, PNG_FP_1, Y) == 0)
+ return 1;
+
+ if (png_muldiv(&XYZ->blue_X, XYZ->blue_X, PNG_FP_1, Y) == 0)
+ return 1;
+ if (png_muldiv(&XYZ->blue_Y, XYZ->blue_Y, PNG_FP_1, Y) == 0)
+ return 1;
+ if (png_muldiv(&XYZ->blue_Z, XYZ->blue_Z, PNG_FP_1, Y) == 0)
+ return 1;
+ }
+
+ return 0;
+}
+
+static int
+png_colorspace_endpoints_match(const png_xy *xy1, const png_xy *xy2, int delta)
+{
+ /* Allow an error of +/-0.01 (absolute value) on each chromaticity */
+ if (PNG_OUT_OF_RANGE(xy1->whitex, xy2->whitex,delta) ||
+ PNG_OUT_OF_RANGE(xy1->whitey, xy2->whitey,delta) ||
+ PNG_OUT_OF_RANGE(xy1->redx, xy2->redx, delta) ||
+ PNG_OUT_OF_RANGE(xy1->redy, xy2->redy, delta) ||
+ PNG_OUT_OF_RANGE(xy1->greenx, xy2->greenx,delta) ||
+ PNG_OUT_OF_RANGE(xy1->greeny, xy2->greeny,delta) ||
+ PNG_OUT_OF_RANGE(xy1->bluex, xy2->bluex, delta) ||
+ PNG_OUT_OF_RANGE(xy1->bluey, xy2->bluey, delta))
+ return 0;
+ return 1;
+}
+
+/* Added in libpng-1.6.0, a different check for the validity of a set of cHRM
+ * chunk chromaticities. Earlier checks used to simply look for the overflow
+ * condition (where the determinant of the matrix to solve for XYZ ends up zero
+ * because the chromaticity values are not all distinct.) Despite this it is
+ * theoretically possible to produce chromaticities that are apparently valid
+ * but that rapidly degrade to invalid, potentially crashing, sets because of
+ * arithmetic inaccuracies when calculations are performed on them. The new
+ * check is to round-trip xy -> XYZ -> xy and then check that the result is
+ * within a small percentage of the original.
+ */
+static int
+png_colorspace_check_xy(png_XYZ *XYZ, const png_xy *xy)
+{
+ int result;
+ png_xy xy_test;
+
+ /* As a side-effect this routine also returns the XYZ endpoints. */
+ result = png_XYZ_from_xy(XYZ, xy);
+ if (result != 0)
+ return result;
+
+ result = png_xy_from_XYZ(&xy_test, XYZ);
+ if (result != 0)
+ return result;
+
+ if (png_colorspace_endpoints_match(xy, &xy_test,
+ 5/*actually, the math is pretty accurate*/) != 0)
+ return 0;
+
+ /* Too much slip */
+ return 1;
+}
+
+/* This is the check going the other way. The XYZ is modified to normalize it
+ * (another side-effect) and the xy chromaticities are returned.
+ */
+static int
+png_colorspace_check_XYZ(png_xy *xy, png_XYZ *XYZ)
+{
+ int result;
+ png_XYZ XYZtemp;
+
+ result = png_XYZ_normalize(XYZ);
+ if (result != 0)
+ return result;
+
+ result = png_xy_from_XYZ(xy, XYZ);
+ if (result != 0)
+ return result;
+
+ XYZtemp = *XYZ;
+ return png_colorspace_check_xy(&XYZtemp, xy);
+}
+
+/* Used to check for an endpoint match against sRGB */
+static const png_xy sRGB_xy = /* From ITU-R BT.709-3 */
+{
+ /* color x y */
+ /* red */ 64000, 33000,
+ /* green */ 30000, 60000,
+ /* blue */ 15000, 6000,
+ /* white */ 31270, 32900
+};
+
+static int
+png_colorspace_set_xy_and_XYZ(png_const_structrp png_ptr,
+ png_colorspacerp colorspace, const png_xy *xy, const png_XYZ *XYZ,
+ int preferred)
+{
+ if ((colorspace->flags & PNG_COLORSPACE_INVALID) != 0)
+ return 0;
+
+ /* The consistency check is performed on the chromaticities; this factors out
+ * variations because of the normalization (or not) of the end point Y
+ * values.
+ */
+ if (preferred < 2 &&
+ (colorspace->flags & PNG_COLORSPACE_HAVE_ENDPOINTS) != 0)
+ {
+ /* The end points must be reasonably close to any we already have. The
+ * following allows an error of up to +/-.001
+ */
+ if (png_colorspace_endpoints_match(xy, &colorspace->end_points_xy,
+ 100) == 0)
+ {
+ colorspace->flags |= PNG_COLORSPACE_INVALID;
+ png_benign_error(png_ptr, "inconsistent chromaticities");
+ return 0; /* failed */
+ }
+
+ /* Only overwrite with preferred values */
+ if (preferred == 0)
+ return 1; /* ok, but no change */
+ }
+
+ colorspace->end_points_xy = *xy;
+ colorspace->end_points_XYZ = *XYZ;
+ colorspace->flags |= PNG_COLORSPACE_HAVE_ENDPOINTS;
+
+ /* The end points are normally quoted to two decimal digits, so allow +/-0.01
+ * on this test.
+ */
+ if (png_colorspace_endpoints_match(xy, &sRGB_xy, 1000) != 0)
+ colorspace->flags |= PNG_COLORSPACE_ENDPOINTS_MATCH_sRGB;
+
+ else
+ colorspace->flags &= PNG_COLORSPACE_CANCEL(
+ PNG_COLORSPACE_ENDPOINTS_MATCH_sRGB);
+
+ return 2; /* ok and changed */
+}
+
+int /* PRIVATE */
+png_colorspace_set_chromaticities(png_const_structrp png_ptr,
+ png_colorspacerp colorspace, const png_xy *xy, int preferred)
+{
+ /* We must check the end points to ensure they are reasonable - in the past
+ * color management systems have crashed as a result of getting bogus
+ * colorant values, while this isn't the fault of libpng it is the
+ * responsibility of libpng because PNG carries the bomb and libpng is in a
+ * position to protect against it.
+ */
+ png_XYZ XYZ;
+
+ switch (png_colorspace_check_xy(&XYZ, xy))
+ {
+ case 0: /* success */
+ return png_colorspace_set_xy_and_XYZ(png_ptr, colorspace, xy, &XYZ,
+ preferred);
+
+ case 1:
+ /* We can't invert the chromaticities so we can't produce value XYZ
+ * values. Likely as not a color management system will fail too.
+ */
+ colorspace->flags |= PNG_COLORSPACE_INVALID;
+ png_benign_error(png_ptr, "invalid chromaticities");
+ break;
+
+ default:
+ /* libpng is broken; this should be a warning but if it happens we
+ * want error reports so for the moment it is an error.
+ */
+ colorspace->flags |= PNG_COLORSPACE_INVALID;
+ png_error(png_ptr, "internal error checking chromaticities");
+ break;
+ }
+
+ return 0; /* failed */
+}
+
+int /* PRIVATE */
+png_colorspace_set_endpoints(png_const_structrp png_ptr,
+ png_colorspacerp colorspace, const png_XYZ *XYZ_in, int preferred)
+{
+ png_XYZ XYZ = *XYZ_in;
+ png_xy xy;
+
+ switch (png_colorspace_check_XYZ(&xy, &XYZ))
+ {
+ case 0:
+ return png_colorspace_set_xy_and_XYZ(png_ptr, colorspace, &xy, &XYZ,
+ preferred);
+
+ case 1:
+ /* End points are invalid. */
+ colorspace->flags |= PNG_COLORSPACE_INVALID;
+ png_benign_error(png_ptr, "invalid end points");
+ break;
+
+ default:
+ colorspace->flags |= PNG_COLORSPACE_INVALID;
+ png_error(png_ptr, "internal error checking chromaticities");
+ break;
+ }
+
+ return 0; /* failed */
+}
+
+#if defined(PNG_sRGB_SUPPORTED) || defined(PNG_iCCP_SUPPORTED)
+/* Error message generation */
+static char
+png_icc_tag_char(png_uint_32 byte)
+{
+ byte &= 0xff;
+ if (byte >= 32 && byte <= 126)
+ return (char)byte;
+ else
+ return '?';
+}
+
+static void
+png_icc_tag_name(char *name, png_uint_32 tag)
+{
+ name[0] = '\'';
+ name[1] = png_icc_tag_char(tag >> 24);
+ name[2] = png_icc_tag_char(tag >> 16);
+ name[3] = png_icc_tag_char(tag >> 8);
+ name[4] = png_icc_tag_char(tag );
+ name[5] = '\'';
+}
+
+static int
+is_ICC_signature_char(png_alloc_size_t it)
+{
+ return it == 32 || (it >= 48 && it <= 57) || (it >= 65 && it <= 90) ||
+ (it >= 97 && it <= 122);
+}
+
+static int
+is_ICC_signature(png_alloc_size_t it)
+{
+ return is_ICC_signature_char(it >> 24) /* checks all the top bits */ &&
+ is_ICC_signature_char((it >> 16) & 0xff) &&
+ is_ICC_signature_char((it >> 8) & 0xff) &&
+ is_ICC_signature_char(it & 0xff);
+}
+
+static int
+png_icc_profile_error(png_const_structrp png_ptr, png_colorspacerp colorspace,
+ png_const_charp name, png_alloc_size_t value, png_const_charp reason)
+{
+ size_t pos;
+ char message[196]; /* see below for calculation */
+
+ if (colorspace != NULL)
+ colorspace->flags |= PNG_COLORSPACE_INVALID;
+
+ pos = png_safecat(message, (sizeof message), 0, "profile '"); /* 9 chars */
+ pos = png_safecat(message, pos+79, pos, name); /* Truncate to 79 chars */
+ pos = png_safecat(message, (sizeof message), pos, "': "); /* +2 = 90 */
+ if (is_ICC_signature(value) != 0)
+ {
+ /* So 'value' is at most 4 bytes and the following cast is safe */
+ png_icc_tag_name(message+pos, (png_uint_32)value);
+ pos += 6; /* total +8; less than the else clause */
+ message[pos++] = ':';
+ message[pos++] = ' ';
+ }
+# ifdef PNG_WARNINGS_SUPPORTED
+ else
+ {
+ char number[PNG_NUMBER_BUFFER_SIZE]; /* +24 = 114*/
+
+ pos = png_safecat(message, (sizeof message), pos,
+ png_format_number(number, number+(sizeof number),
+ PNG_NUMBER_FORMAT_x, value));
+ pos = png_safecat(message, (sizeof message), pos, "h: "); /*+2 = 116*/
+ }
+# endif
+ /* The 'reason' is an arbitrary message, allow +79 maximum 195 */
+ pos = png_safecat(message, (sizeof message), pos, reason);
+ PNG_UNUSED(pos)
+
+ /* This is recoverable, but make it unconditionally an app_error on write to
+ * avoid writing invalid ICC profiles into PNG files (i.e., we handle them
+ * on read, with a warning, but on write unless the app turns off
+ * application errors the PNG won't be written.)
+ */
+ png_chunk_report(png_ptr, message,
+ (colorspace != NULL) ? PNG_CHUNK_ERROR : PNG_CHUNK_WRITE_ERROR);
+
+ return 0;
+}
+#endif /* sRGB || iCCP */
+
+#ifdef PNG_sRGB_SUPPORTED
+int /* PRIVATE */
+png_colorspace_set_sRGB(png_const_structrp png_ptr, png_colorspacerp colorspace,
+ int intent)
+{
+ /* sRGB sets known gamma, end points and (from the chunk) intent. */
+ /* IMPORTANT: these are not necessarily the values found in an ICC profile
+ * because ICC profiles store values adapted to a D50 environment; it is
+ * expected that the ICC profile mediaWhitePointTag will be D50; see the
+ * checks and code elsewhere to understand this better.
+ *
+ * These XYZ values, which are accurate to 5dp, produce rgb to gray
+ * coefficients of (6968,23435,2366), which are reduced (because they add up
+ * to 32769 not 32768) to (6968,23434,2366). These are the values that
+ * libpng has traditionally used (and are the best values given the 15bit
+ * algorithm used by the rgb to gray code.)
+ */
+ static const png_XYZ sRGB_XYZ = /* D65 XYZ (*not* the D50 adapted values!) */
+ {
+ /* color X Y Z */
+ /* red */ 41239, 21264, 1933,
+ /* green */ 35758, 71517, 11919,
+ /* blue */ 18048, 7219, 95053
+ };
+
+ /* Do nothing if the colorspace is already invalidated. */
+ if ((colorspace->flags & PNG_COLORSPACE_INVALID) != 0)
+ return 0;
+
+ /* Check the intent, then check for existing settings. It is valid for the
+ * PNG file to have cHRM or gAMA chunks along with sRGB, but the values must
+ * be consistent with the correct values. If, however, this function is
+ * called below because an iCCP chunk matches sRGB then it is quite
+ * conceivable that an older app recorded incorrect gAMA and cHRM because of
+ * an incorrect calculation based on the values in the profile - this does
+ * *not* invalidate the profile (though it still produces an error, which can
+ * be ignored.)
+ */
+ if (intent < 0 || intent >= PNG_sRGB_INTENT_LAST)
+ return png_icc_profile_error(png_ptr, colorspace, "sRGB",
+ (unsigned)intent, "invalid sRGB rendering intent");
+
+ if ((colorspace->flags & PNG_COLORSPACE_HAVE_INTENT) != 0 &&
+ colorspace->rendering_intent != intent)
+ return png_icc_profile_error(png_ptr, colorspace, "sRGB",
+ (unsigned)intent, "inconsistent rendering intents");
+
+ if ((colorspace->flags & PNG_COLORSPACE_FROM_sRGB) != 0)
+ {
+ png_benign_error(png_ptr, "duplicate sRGB information ignored");
+ return 0;
+ }
+
+ /* If the standard sRGB cHRM chunk does not match the one from the PNG file
+ * warn but overwrite the value with the correct one.
+ */
+ if ((colorspace->flags & PNG_COLORSPACE_HAVE_ENDPOINTS) != 0 &&
+ !png_colorspace_endpoints_match(&sRGB_xy, &colorspace->end_points_xy,
+ 100))
+ png_chunk_report(png_ptr, "cHRM chunk does not match sRGB",
+ PNG_CHUNK_ERROR);
+
+ /* This check is just done for the error reporting - the routine always
+ * returns true when the 'from' argument corresponds to sRGB (2).
+ */
+ (void)png_colorspace_check_gamma(png_ptr, colorspace, PNG_GAMMA_sRGB_INVERSE,
+ 2/*from sRGB*/);
+
+ /* intent: bugs in GCC force 'int' to be used as the parameter type. */
+ colorspace->rendering_intent = (png_uint_16)intent;
+ colorspace->flags |= PNG_COLORSPACE_HAVE_INTENT;
+
+ /* endpoints */
+ colorspace->end_points_xy = sRGB_xy;
+ colorspace->end_points_XYZ = sRGB_XYZ;
+ colorspace->flags |=
+ (PNG_COLORSPACE_HAVE_ENDPOINTS|PNG_COLORSPACE_ENDPOINTS_MATCH_sRGB);
+
+ /* gamma */
+ colorspace->gamma = PNG_GAMMA_sRGB_INVERSE;
+ colorspace->flags |= PNG_COLORSPACE_HAVE_GAMMA;
+
+ /* Finally record that we have an sRGB profile */
+ colorspace->flags |=
+ (PNG_COLORSPACE_MATCHES_sRGB|PNG_COLORSPACE_FROM_sRGB);
+
+ return 1; /* set */
+}
+#endif /* sRGB */
+
+#ifdef PNG_iCCP_SUPPORTED
+/* Encoded value of D50 as an ICC XYZNumber. From the ICC 2010 spec the value
+ * is XYZ(0.9642,1.0,0.8249), which scales to:
+ *
+ * (63189.8112, 65536, 54060.6464)
+ */
+static const png_byte D50_nCIEXYZ[12] =
+ { 0x00, 0x00, 0xf6, 0xd6, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00, 0xd3, 0x2d };
+
+int /* PRIVATE */
+png_icc_check_length(png_const_structrp png_ptr, png_colorspacerp colorspace,
+ png_const_charp name, png_uint_32 profile_length)
+{
+ if (profile_length < 132)
+ return png_icc_profile_error(png_ptr, colorspace, name, profile_length,
+ "too short");
+
+ return 1;
+}
+
+int /* PRIVATE */
+png_icc_check_header(png_const_structrp png_ptr, png_colorspacerp colorspace,
+ png_const_charp name, png_uint_32 profile_length,
+ png_const_bytep profile/* first 132 bytes only */, int color_type)
+{
+ png_uint_32 temp;
+
+ /* Length check; this cannot be ignored in this code because profile_length
+ * is used later to check the tag table, so even if the profile seems over
+ * long profile_length from the caller must be correct. The caller can fix
+ * this up on read or write by just passing in the profile header length.
+ */
+ temp = png_get_uint_32(profile);
+ if (temp != profile_length)
+ return png_icc_profile_error(png_ptr, colorspace, name, temp,
+ "length does not match profile");
+
+ temp = (png_uint_32) (*(profile+8));
+ if (temp > 3 && (profile_length & 3))
+ return png_icc_profile_error(png_ptr, colorspace, name, profile_length,
+ "invalid length");
+
+ temp = png_get_uint_32(profile+128); /* tag count: 12 bytes/tag */
+ if (temp > 357913930 || /* (2^32-4-132)/12: maximum possible tag count */
+ profile_length < 132+12*temp) /* truncated tag table */
+ return png_icc_profile_error(png_ptr, colorspace, name, temp,
+ "tag count too large");
+
+ /* The 'intent' must be valid or we can't store it, ICC limits the intent to
+ * 16 bits.
+ */
+ temp = png_get_uint_32(profile+64);
+ if (temp >= 0xffff) /* The ICC limit */
+ return png_icc_profile_error(png_ptr, colorspace, name, temp,
+ "invalid rendering intent");
+
+ /* This is just a warning because the profile may be valid in future
+ * versions.
+ */
+ if (temp >= PNG_sRGB_INTENT_LAST)
+ (void)png_icc_profile_error(png_ptr, NULL, name, temp,
+ "intent outside defined range");
+
+ /* At this point the tag table can't be checked because it hasn't necessarily
+ * been loaded; however, various header fields can be checked. These checks
+ * are for values permitted by the PNG spec in an ICC profile; the PNG spec
+ * restricts the profiles that can be passed in an iCCP chunk (they must be
+ * appropriate to processing PNG data!)
+ */
+
+ /* Data checks (could be skipped). These checks must be independent of the
+ * version number; however, the version number doesn't accomodate changes in
+ * the header fields (just the known tags and the interpretation of the
+ * data.)
+ */
+ temp = png_get_uint_32(profile+36); /* signature 'ascp' */
+ if (temp != 0x61637370)
+ return png_icc_profile_error(png_ptr, colorspace, name, temp,
+ "invalid signature");
+
+ /* Currently the PCS illuminant/adopted white point (the computational
+ * white point) are required to be D50,
+ * however the profile contains a record of the illuminant so perhaps ICC
+ * expects to be able to change this in the future (despite the rationale in
+ * the introduction for using a fixed PCS adopted white.) Consequently the
+ * following is just a warning.
+ */
+ if (memcmp(profile+68, D50_nCIEXYZ, 12) != 0)
+ (void)png_icc_profile_error(png_ptr, NULL, name, 0/*no tag value*/,
+ "PCS illuminant is not D50");
+
+ /* The PNG spec requires this:
+ * "If the iCCP chunk is present, the image samples conform to the colour
+ * space represented by the embedded ICC profile as defined by the
+ * International Color Consortium [ICC]. The colour space of the ICC profile
+ * shall be an RGB colour space for colour images (PNG colour types 2, 3, and
+ * 6), or a greyscale colour space for greyscale images (PNG colour types 0
+ * and 4)."
+ *
+ * This checking code ensures the embedded profile (on either read or write)
+ * conforms to the specification requirements. Notice that an ICC 'gray'
+ * color-space profile contains the information to transform the monochrome
+ * data to XYZ or L*a*b (according to which PCS the profile uses) and this
+ * should be used in preference to the standard libpng K channel replication
+ * into R, G and B channels.
+ *
+ * Previously it was suggested that an RGB profile on grayscale data could be
+ * handled. However it it is clear that using an RGB profile in this context
+ * must be an error - there is no specification of what it means. Thus it is
+ * almost certainly more correct to ignore the profile.
+ */
+ temp = png_get_uint_32(profile+16); /* data colour space field */
+ switch (temp)
+ {
+ case 0x52474220: /* 'RGB ' */
+ if ((color_type & PNG_COLOR_MASK_COLOR) == 0)
+ return png_icc_profile_error(png_ptr, colorspace, name, temp,
+ "RGB color space not permitted on grayscale PNG");
+ break;
+
+ case 0x47524159: /* 'GRAY' */
+ if ((color_type & PNG_COLOR_MASK_COLOR) != 0)
+ return png_icc_profile_error(png_ptr, colorspace, name, temp,
+ "Gray color space not permitted on RGB PNG");
+ break;
+
+ default:
+ return png_icc_profile_error(png_ptr, colorspace, name, temp,
+ "invalid ICC profile color space");
+ }
+
+ /* It is up to the application to check that the profile class matches the
+ * application requirements; the spec provides no guidance, but it's pretty
+ * weird if the profile is not scanner ('scnr'), monitor ('mntr'), printer
+ * ('prtr') or 'spac' (for generic color spaces). Issue a warning in these
+ * cases. Issue an error for device link or abstract profiles - these don't
+ * contain the records necessary to transform the color-space to anything
+ * other than the target device (and not even that for an abstract profile).
+ * Profiles of these classes may not be embedded in images.
+ */
+ temp = png_get_uint_32(profile+12); /* profile/device class */
+ switch (temp)
+ {
+ case 0x73636E72: /* 'scnr' */
+ case 0x6D6E7472: /* 'mntr' */
+ case 0x70727472: /* 'prtr' */
+ case 0x73706163: /* 'spac' */
+ /* All supported */
+ break;
+
+ case 0x61627374: /* 'abst' */
+ /* May not be embedded in an image */
+ return png_icc_profile_error(png_ptr, colorspace, name, temp,
+ "invalid embedded Abstract ICC profile");
+
+ case 0x6C696E6B: /* 'link' */
+ /* DeviceLink profiles cannot be interpreted in a non-device specific
+ * fashion, if an app uses the AToB0Tag in the profile the results are
+ * undefined unless the result is sent to the intended device,
+ * therefore a DeviceLink profile should not be found embedded in a
+ * PNG.
+ */
+ return png_icc_profile_error(png_ptr, colorspace, name, temp,
+ "unexpected DeviceLink ICC profile class");
+
+ case 0x6E6D636C: /* 'nmcl' */
+ /* A NamedColor profile is also device specific, however it doesn't
+ * contain an AToB0 tag that is open to misinterpretation. Almost
+ * certainly it will fail the tests below.
+ */
+ (void)png_icc_profile_error(png_ptr, NULL, name, temp,
+ "unexpected NamedColor ICC profile class");
+ break;
+
+ default:
+ /* To allow for future enhancements to the profile accept unrecognized
+ * profile classes with a warning, these then hit the test below on the
+ * tag content to ensure they are backward compatible with one of the
+ * understood profiles.
+ */
+ (void)png_icc_profile_error(png_ptr, NULL, name, temp,
+ "unrecognized ICC profile class");
+ break;
+ }
+
+ /* For any profile other than a device link one the PCS must be encoded
+ * either in XYZ or Lab.
+ */
+ temp = png_get_uint_32(profile+20);
+ switch (temp)
+ {
+ case 0x58595A20: /* 'XYZ ' */
+ case 0x4C616220: /* 'Lab ' */
+ break;
+
+ default:
+ return png_icc_profile_error(png_ptr, colorspace, name, temp,
+ "unexpected ICC PCS encoding");
+ }
+
+ return 1;
+}
+
+int /* PRIVATE */
+png_icc_check_tag_table(png_const_structrp png_ptr, png_colorspacerp colorspace,
+ png_const_charp name, png_uint_32 profile_length,
+ png_const_bytep profile /* header plus whole tag table */)
+{
+ png_uint_32 tag_count = png_get_uint_32(profile+128);
+ png_uint_32 itag;
+ png_const_bytep tag = profile+132; /* The first tag */
+
+ /* First scan all the tags in the table and add bits to the icc_info value
+ * (temporarily in 'tags').
+ */
+ for (itag=0; itag < tag_count; ++itag, tag += 12)
+ {
+ png_uint_32 tag_id = png_get_uint_32(tag+0);
+ png_uint_32 tag_start = png_get_uint_32(tag+4); /* must be aligned */
+ png_uint_32 tag_length = png_get_uint_32(tag+8);/* not padded */
+
+ /* The ICC specification does not exclude zero length tags, therefore the
+ * start might actually be anywhere if there is no data, but this would be
+ * a clear abuse of the intent of the standard so the start is checked for
+ * being in range. All defined tag types have an 8 byte header - a 4 byte
+ * type signature then 0.
+ */
+ if ((tag_start & 3) != 0)
+ {
+ /* CNHP730S.icc shipped with Microsoft Windows 64 violates this, it is
+ * only a warning here because libpng does not care about the
+ * alignment.
+ */
+ (void)png_icc_profile_error(png_ptr, NULL, name, tag_id,
+ "ICC profile tag start not a multiple of 4");
+ }
+
+ /* This is a hard error; potentially it can cause read outside the
+ * profile.
+ */
+ if (tag_start > profile_length || tag_length > profile_length - tag_start)
+ return png_icc_profile_error(png_ptr, colorspace, name, tag_id,
+ "ICC profile tag outside profile");
+ }
+
+ return 1; /* success, maybe with warnings */
+}
+
+#ifdef PNG_sRGB_SUPPORTED
+#if PNG_sRGB_PROFILE_CHECKS >= 0
+/* Information about the known ICC sRGB profiles */
+static const struct
+{
+ png_uint_32 adler, crc, length;
+ png_uint_32 md5[4];
+ png_byte have_md5;
+ png_byte is_broken;
+ png_uint_16 intent;
+
+# define PNG_MD5(a,b,c,d) { a, b, c, d }, (a!=0)||(b!=0)||(c!=0)||(d!=0)
+# define PNG_ICC_CHECKSUM(adler, crc, md5, intent, broke, date, length, fname)\
+ { adler, crc, length, md5, broke, intent },
+
+} png_sRGB_checks[] =
+{
+ /* This data comes from contrib/tools/checksum-icc run on downloads of
+ * all four ICC sRGB profiles from www.color.org.
+ */
+ /* adler32, crc32, MD5[4], intent, date, length, file-name */
+ PNG_ICC_CHECKSUM(0x0a3fd9f6, 0x3b8772b9,
+ PNG_MD5(0x29f83dde, 0xaff255ae, 0x7842fae4, 0xca83390d), 0, 0,
+ "2009/03/27 21:36:31", 3048, "sRGB_IEC61966-2-1_black_scaled.icc")
+
+ /* ICC sRGB v2 perceptual no black-compensation: */
+ PNG_ICC_CHECKSUM(0x4909e5e1, 0x427ebb21,
+ PNG_MD5(0xc95bd637, 0xe95d8a3b, 0x0df38f99, 0xc1320389), 1, 0,
+ "2009/03/27 21:37:45", 3052, "sRGB_IEC61966-2-1_no_black_scaling.icc")
+
+ PNG_ICC_CHECKSUM(0xfd2144a1, 0x306fd8ae,
+ PNG_MD5(0xfc663378, 0x37e2886b, 0xfd72e983, 0x8228f1b8), 0, 0,
+ "2009/08/10 17:28:01", 60988, "sRGB_v4_ICC_preference_displayclass.icc")
+
+ /* ICC sRGB v4 perceptual */
+ PNG_ICC_CHECKSUM(0x209c35d2, 0xbbef7812,
+ PNG_MD5(0x34562abf, 0x994ccd06, 0x6d2c5721, 0xd0d68c5d), 0, 0,
+ "2007/07/25 00:05:37", 60960, "sRGB_v4_ICC_preference.icc")
+
+ /* The following profiles have no known MD5 checksum. If there is a match
+ * on the (empty) MD5 the other fields are used to attempt a match and
+ * a warning is produced. The first two of these profiles have a 'cprt' tag
+ * which suggests that they were also made by Hewlett Packard.
+ */
+ PNG_ICC_CHECKSUM(0xa054d762, 0x5d5129ce,
+ PNG_MD5(0x00000000, 0x00000000, 0x00000000, 0x00000000), 1, 0,
+ "2004/07/21 18:57:42", 3024, "sRGB_IEC61966-2-1_noBPC.icc")
+
+ /* This is a 'mntr' (display) profile with a mediaWhitePointTag that does not
+ * match the D50 PCS illuminant in the header (it is in fact the D65 values,
+ * so the white point is recorded as the un-adapted value.) The profiles
+ * below only differ in one byte - the intent - and are basically the same as
+ * the previous profile except for the mediaWhitePointTag error and a missing
+ * chromaticAdaptationTag.
+ */
+ PNG_ICC_CHECKSUM(0xf784f3fb, 0x182ea552,
+ PNG_MD5(0x00000000, 0x00000000, 0x00000000, 0x00000000), 0, 1/*broken*/,
+ "1998/02/09 06:49:00", 3144, "HP-Microsoft sRGB v2 perceptual")
+
+ PNG_ICC_CHECKSUM(0x0398f3fc, 0xf29e526d,
+ PNG_MD5(0x00000000, 0x00000000, 0x00000000, 0x00000000), 1, 1/*broken*/,
+ "1998/02/09 06:49:00", 3144, "HP-Microsoft sRGB v2 media-relative")
+};
+
+static int
+png_compare_ICC_profile_with_sRGB(png_const_structrp png_ptr,
+ png_const_bytep profile, uLong adler)
+{
+ /* The quick check is to verify just the MD5 signature and trust the
+ * rest of the data. Because the profile has already been verified for
+ * correctness this is safe. png_colorspace_set_sRGB will check the 'intent'
+ * field too, so if the profile has been edited with an intent not defined
+ * by sRGB (but maybe defined by a later ICC specification) the read of
+ * the profile will fail at that point.
+ */
+
+ png_uint_32 length = 0;
+ png_uint_32 intent = 0x10000; /* invalid */
+#if PNG_sRGB_PROFILE_CHECKS > 1
+ uLong crc = 0; /* the value for 0 length data */
+#endif
+ unsigned int i;
+
+#ifdef PNG_SET_OPTION_SUPPORTED
+ /* First see if PNG_SKIP_sRGB_CHECK_PROFILE has been set to "on" */
+ if (((png_ptr->options >> PNG_SKIP_sRGB_CHECK_PROFILE) & 3) ==
+ PNG_OPTION_ON)
+ return 0;
+#endif
+
+ for (i=0; i < (sizeof png_sRGB_checks) / (sizeof png_sRGB_checks[0]); ++i)
+ {
+ if (png_get_uint_32(profile+84) == png_sRGB_checks[i].md5[0] &&
+ png_get_uint_32(profile+88) == png_sRGB_checks[i].md5[1] &&
+ png_get_uint_32(profile+92) == png_sRGB_checks[i].md5[2] &&
+ png_get_uint_32(profile+96) == png_sRGB_checks[i].md5[3])
+ {
+ /* This may be one of the old HP profiles without an MD5, in that
+ * case we can only use the length and Adler32 (note that these
+ * are not used by default if there is an MD5!)
+ */
+# if PNG_sRGB_PROFILE_CHECKS == 0
+ if (png_sRGB_checks[i].have_md5 != 0)
+ return 1+png_sRGB_checks[i].is_broken;
+# endif
+
+ /* Profile is unsigned or more checks have been configured in. */
+ if (length == 0)
+ {
+ length = png_get_uint_32(profile);
+ intent = png_get_uint_32(profile+64);
+ }
+
+ /* Length *and* intent must match */
+ if (length == png_sRGB_checks[i].length &&
+ intent == png_sRGB_checks[i].intent)
+ {
+ /* Now calculate the adler32 if not done already. */
+ if (adler == 0)
+ {
+ adler = adler32(0, NULL, 0);
+ adler = adler32(adler, profile, length);
+ }
+
+ if (adler == png_sRGB_checks[i].adler)
+ {
+ /* These basic checks suggest that the data has not been
+ * modified, but if the check level is more than 1 perform
+ * our own crc32 checksum on the data.
+ */
+# if PNG_sRGB_PROFILE_CHECKS > 1
+ if (crc == 0)
+ {
+ crc = crc32(0, NULL, 0);
+ crc = crc32(crc, profile, length);
+ }
+
+ /* So this check must pass for the 'return' below to happen.
+ */
+ if (crc == png_sRGB_checks[i].crc)
+# endif
+ {
+ if (png_sRGB_checks[i].is_broken != 0)
+ {
+ /* These profiles are known to have bad data that may cause
+ * problems if they are used, therefore attempt to
+ * discourage their use, skip the 'have_md5' warning below,
+ * which is made irrelevant by this error.
+ */
+ png_chunk_report(png_ptr, "known incorrect sRGB profile",
+ PNG_CHUNK_ERROR);
+ }
+
+ /* Warn that this being done; this isn't even an error since
+ * the profile is perfectly valid, but it would be nice if
+ * people used the up-to-date ones.
+ */
+ else if (png_sRGB_checks[i].have_md5 == 0)
+ {
+ png_chunk_report(png_ptr,
+ "out-of-date sRGB profile with no signature",
+ PNG_CHUNK_WARNING);
+ }
+
+ return 1+png_sRGB_checks[i].is_broken;
+ }
+ }
+
+# if PNG_sRGB_PROFILE_CHECKS > 0
+ /* The signature matched, but the profile had been changed in some
+ * way. This probably indicates a data error or uninformed hacking.
+ * Fall through to "no match".
+ */
+ png_chunk_report(png_ptr,
+ "Not recognizing known sRGB profile that has been edited",
+ PNG_CHUNK_WARNING);
+ break;
+# endif
+ }
+ }
+ }
+
+ return 0; /* no match */
+}
+#endif /* PNG_sRGB_PROFILE_CHECKS >= 0 */
+
+void /* PRIVATE */
+png_icc_set_sRGB(png_const_structrp png_ptr,
+ png_colorspacerp colorspace, png_const_bytep profile, uLong adler)
+{
+ /* Is this profile one of the known ICC sRGB profiles? If it is, just set
+ * the sRGB information.
+ */
+#if PNG_sRGB_PROFILE_CHECKS >= 0
+ if (png_compare_ICC_profile_with_sRGB(png_ptr, profile, adler) != 0)
+#endif
+ (void)png_colorspace_set_sRGB(png_ptr, colorspace,
+ (int)/*already checked*/png_get_uint_32(profile+64));
+}
+#endif /* sRGB */
+
+int /* PRIVATE */
+png_colorspace_set_ICC(png_const_structrp png_ptr, png_colorspacerp colorspace,
+ png_const_charp name, png_uint_32 profile_length, png_const_bytep profile,
+ int color_type)
+{
+ if ((colorspace->flags & PNG_COLORSPACE_INVALID) != 0)
+ return 0;
+
+ if (png_icc_check_length(png_ptr, colorspace, name, profile_length) != 0 &&
+ png_icc_check_header(png_ptr, colorspace, name, profile_length, profile,
+ color_type) != 0 &&
+ png_icc_check_tag_table(png_ptr, colorspace, name, profile_length,
+ profile) != 0)
+ {
+# ifdef PNG_sRGB_SUPPORTED
+ /* If no sRGB support, don't try storing sRGB information */
+ png_icc_set_sRGB(png_ptr, colorspace, profile, 0);
+# endif
+ return 1;
+ }
+
+ /* Failure case */
+ return 0;
+}
+#endif /* iCCP */
+
+#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
+void /* PRIVATE */
+png_colorspace_set_rgb_coefficients(png_structrp png_ptr)
+{
+ /* Set the rgb_to_gray coefficients from the colorspace. */
+ if (png_ptr->rgb_to_gray_coefficients_set == 0 &&
+ (png_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_ENDPOINTS) != 0)
+ {
+ /* png_set_background has not been called, get the coefficients from the Y
+ * values of the colorspace colorants.
+ */
+ png_fixed_point r = png_ptr->colorspace.end_points_XYZ.red_Y;
+ png_fixed_point g = png_ptr->colorspace.end_points_XYZ.green_Y;
+ png_fixed_point b = png_ptr->colorspace.end_points_XYZ.blue_Y;
+ png_fixed_point total = r+g+b;
+
+ if (total > 0 &&
+ r >= 0 && png_muldiv(&r, r, 32768, total) && r >= 0 && r <= 32768 &&
+ g >= 0 && png_muldiv(&g, g, 32768, total) && g >= 0 && g <= 32768 &&
+ b >= 0 && png_muldiv(&b, b, 32768, total) && b >= 0 && b <= 32768 &&
+ r+g+b <= 32769)
+ {
+ /* We allow 0 coefficients here. r+g+b may be 32769 if two or
+ * all of the coefficients were rounded up. Handle this by
+ * reducing the *largest* coefficient by 1; this matches the
+ * approach used for the default coefficients in pngrtran.c
+ */
+ int add = 0;
+
+ if (r+g+b > 32768)
+ add = -1;
+ else if (r+g+b < 32768)
+ add = 1;
+
+ if (add != 0)
+ {
+ if (g >= r && g >= b)
+ g += add;
+ else if (r >= g && r >= b)
+ r += add;
+ else
+ b += add;
+ }
+
+ /* Check for an internal error. */
+ if (r+g+b != 32768)
+ png_error(png_ptr,
+ "internal error handling cHRM coefficients");
+
+ else
+ {
+ png_ptr->rgb_to_gray_red_coeff = (png_uint_16)r;
+ png_ptr->rgb_to_gray_green_coeff = (png_uint_16)g;
+ }
+ }
+
+ /* This is a png_error at present even though it could be ignored -
+ * it should never happen, but it is important that if it does, the
+ * bug is fixed.
+ */
+ else
+ png_error(png_ptr, "internal error handling cHRM->XYZ");
+ }
+}
+#endif /* READ_RGB_TO_GRAY */
+
+#endif /* COLORSPACE */
+
+#ifdef __GNUC__
+/* This exists solely to work round a warning from GNU C. */
+static int /* PRIVATE */
+png_gt(size_t a, size_t b)
+{
+ return a > b;
+}
+#else
+# define png_gt(a,b) ((a) > (b))
+#endif
+
+void /* PRIVATE */
+png_check_IHDR(png_const_structrp png_ptr,
+ png_uint_32 width, png_uint_32 height, int bit_depth,
+ int color_type, int interlace_type, int compression_type,
+ int filter_type)
+{
+ int error = 0;
+
+ /* Check for width and height valid values */
+ if (width == 0)
+ {
+ png_warning(png_ptr, "Image width is zero in IHDR");
+ error = 1;
+ }
+
+ if (width > PNG_UINT_31_MAX)
+ {
+ png_warning(png_ptr, "Invalid image width in IHDR");
+ error = 1;
+ }
+
+ if (png_gt(((width + 7) & (~7)),
+ ((PNG_SIZE_MAX
+ - 48 /* big_row_buf hack */
+ - 1) /* filter byte */
+ / 8) /* 8-byte RGBA pixels */
+ - 1)) /* extra max_pixel_depth pad */
+ {
+ /* The size of the row must be within the limits of this architecture.
+ * Because the read code can perform arbitrary transformations the
+ * maximum size is checked here. Because the code in png_read_start_row
+ * adds extra space "for safety's sake" in several places a conservative
+ * limit is used here.
+ *
+ * NOTE: it would be far better to check the size that is actually used,
+ * but the effect in the real world is minor and the changes are more
+ * extensive, therefore much more dangerous and much more difficult to
+ * write in a way that avoids compiler warnings.
+ */
+ png_warning(png_ptr, "Image width is too large for this architecture");
+ error = 1;
+ }
+
+#ifdef PNG_SET_USER_LIMITS_SUPPORTED
+ if (width > png_ptr->user_width_max)
+#else
+ if (width > PNG_USER_WIDTH_MAX)
+#endif
+ {
+ png_warning(png_ptr, "Image width exceeds user limit in IHDR");
+ error = 1;
+ }
+
+ if (height == 0)
+ {
+ png_warning(png_ptr, "Image height is zero in IHDR");
+ error = 1;
+ }
+
+ if (height > PNG_UINT_31_MAX)
+ {
+ png_warning(png_ptr, "Invalid image height in IHDR");
+ error = 1;
+ }
+
+#ifdef PNG_SET_USER_LIMITS_SUPPORTED
+ if (height > png_ptr->user_height_max)
+#else
+ if (height > PNG_USER_HEIGHT_MAX)
+#endif
+ {
+ png_warning(png_ptr, "Image height exceeds user limit in IHDR");
+ error = 1;
+ }
+
+ /* Check other values */
+ if (bit_depth != 1 && bit_depth != 2 && bit_depth != 4 &&
+ bit_depth != 8 && bit_depth != 16)
+ {
+ png_warning(png_ptr, "Invalid bit depth in IHDR");
+ error = 1;
+ }
+
+ if (color_type < 0 || color_type == 1 ||
+ color_type == 5 || color_type > 6)
+ {
+ png_warning(png_ptr, "Invalid color type in IHDR");
+ error = 1;
+ }
+
+ if (((color_type == PNG_COLOR_TYPE_PALETTE) && bit_depth > 8) ||
+ ((color_type == PNG_COLOR_TYPE_RGB ||
+ color_type == PNG_COLOR_TYPE_GRAY_ALPHA ||
+ color_type == PNG_COLOR_TYPE_RGB_ALPHA) && bit_depth < 8))
+ {
+ png_warning(png_ptr, "Invalid color type/bit depth combination in IHDR");
+ error = 1;
+ }
+
+ if (interlace_type >= PNG_INTERLACE_LAST)
+ {
+ png_warning(png_ptr, "Unknown interlace method in IHDR");
+ error = 1;
+ }
+
+ if (compression_type != PNG_COMPRESSION_TYPE_BASE)
+ {
+ png_warning(png_ptr, "Unknown compression method in IHDR");
+ error = 1;
+ }
+
+#ifdef PNG_MNG_FEATURES_SUPPORTED
+ /* Accept filter_method 64 (intrapixel differencing) only if
+ * 1. Libpng was compiled with PNG_MNG_FEATURES_SUPPORTED and
+ * 2. Libpng did not read a PNG signature (this filter_method is only
+ * used in PNG datastreams that are embedded in MNG datastreams) and
+ * 3. The application called png_permit_mng_features with a mask that
+ * included PNG_FLAG_MNG_FILTER_64 and
+ * 4. The filter_method is 64 and
+ * 5. The color_type is RGB or RGBA
+ */
+ if ((png_ptr->mode & PNG_HAVE_PNG_SIGNATURE) != 0 &&
+ png_ptr->mng_features_permitted != 0)
+ png_warning(png_ptr, "MNG features are not allowed in a PNG datastream");
+
+ if (filter_type != PNG_FILTER_TYPE_BASE)
+ {
+ if (!((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) != 0 &&
+ (filter_type == PNG_INTRAPIXEL_DIFFERENCING) &&
+ ((png_ptr->mode & PNG_HAVE_PNG_SIGNATURE) == 0) &&
+ (color_type == PNG_COLOR_TYPE_RGB ||
+ color_type == PNG_COLOR_TYPE_RGB_ALPHA)))
+ {
+ png_warning(png_ptr, "Unknown filter method in IHDR");
+ error = 1;
+ }
+
+ if ((png_ptr->mode & PNG_HAVE_PNG_SIGNATURE) != 0)
+ {
+ png_warning(png_ptr, "Invalid filter method in IHDR");
+ error = 1;
+ }
+ }
+
+#else
+ if (filter_type != PNG_FILTER_TYPE_BASE)
+ {
+ png_warning(png_ptr, "Unknown filter method in IHDR");
+ error = 1;
+ }
+#endif
+
+ if (error == 1)
+ png_error(png_ptr, "Invalid IHDR data");
+}
+
+#if defined(PNG_sCAL_SUPPORTED) || defined(PNG_pCAL_SUPPORTED)
+/* ASCII to fp functions */
+/* Check an ASCII formated floating point value, see the more detailed
+ * comments in pngpriv.h
+ */
+/* The following is used internally to preserve the sticky flags */
+#define png_fp_add(state, flags) ((state) |= (flags))
+#define png_fp_set(state, value) ((state) = (value) | ((state) & PNG_FP_STICKY))
+
+int /* PRIVATE */
+png_check_fp_number(png_const_charp string, png_size_t size, int *statep,
+ png_size_tp whereami)
+{
+ int state = *statep;
+ png_size_t i = *whereami;
+
+ while (i < size)
+ {
+ int type;
+ /* First find the type of the next character */
+ switch (string[i])
+ {
+ case 43: type = PNG_FP_SAW_SIGN; break;
+ case 45: type = PNG_FP_SAW_SIGN + PNG_FP_NEGATIVE; break;
+ case 46: type = PNG_FP_SAW_DOT; break;
+ case 48: type = PNG_FP_SAW_DIGIT; break;
+ case 49: case 50: case 51: case 52:
+ case 53: case 54: case 55: case 56:
+ case 57: type = PNG_FP_SAW_DIGIT + PNG_FP_NONZERO; break;
+ case 69:
+ case 101: type = PNG_FP_SAW_E; break;
+ default: goto PNG_FP_End;
+ }
+
+ /* Now deal with this type according to the current
+ * state, the type is arranged to not overlap the
+ * bits of the PNG_FP_STATE.
+ */
+ switch ((state & PNG_FP_STATE) + (type & PNG_FP_SAW_ANY))
+ {
+ case PNG_FP_INTEGER + PNG_FP_SAW_SIGN:
+ if ((state & PNG_FP_SAW_ANY) != 0)
+ goto PNG_FP_End; /* not a part of the number */
+
+ png_fp_add(state, type);
+ break;
+
+ case PNG_FP_INTEGER + PNG_FP_SAW_DOT:
+ /* Ok as trailer, ok as lead of fraction. */
+ if ((state & PNG_FP_SAW_DOT) != 0) /* two dots */
+ goto PNG_FP_End;
+
+ else if ((state & PNG_FP_SAW_DIGIT) != 0) /* trailing dot? */
+ png_fp_add(state, type);
+
+ else
+ png_fp_set(state, PNG_FP_FRACTION | type);
+
+ break;
+
+ case PNG_FP_INTEGER + PNG_FP_SAW_DIGIT:
+ if ((state & PNG_FP_SAW_DOT) != 0) /* delayed fraction */
+ png_fp_set(state, PNG_FP_FRACTION | PNG_FP_SAW_DOT);
+
+ png_fp_add(state, type | PNG_FP_WAS_VALID);
+
+ break;
+
+ case PNG_FP_INTEGER + PNG_FP_SAW_E:
+ if ((state & PNG_FP_SAW_DIGIT) == 0)
+ goto PNG_FP_End;
+
+ png_fp_set(state, PNG_FP_EXPONENT);
+
+ break;
+
+ /* case PNG_FP_FRACTION + PNG_FP_SAW_SIGN:
+ goto PNG_FP_End; ** no sign in fraction */
+
+ /* case PNG_FP_FRACTION + PNG_FP_SAW_DOT:
+ goto PNG_FP_End; ** Because SAW_DOT is always set */
+
+ case PNG_FP_FRACTION + PNG_FP_SAW_DIGIT:
+ png_fp_add(state, type | PNG_FP_WAS_VALID);
+ break;
+
+ case PNG_FP_FRACTION + PNG_FP_SAW_E:
+ /* This is correct because the trailing '.' on an
+ * integer is handled above - so we can only get here
+ * with the sequence ".E" (with no preceding digits).
+ */
+ if ((state & PNG_FP_SAW_DIGIT) == 0)
+ goto PNG_FP_End;
+
+ png_fp_set(state, PNG_FP_EXPONENT);
+
+ break;
+
+ case PNG_FP_EXPONENT + PNG_FP_SAW_SIGN:
+ if ((state & PNG_FP_SAW_ANY) != 0)
+ goto PNG_FP_End; /* not a part of the number */
+
+ png_fp_add(state, PNG_FP_SAW_SIGN);
+
+ break;
+
+ /* case PNG_FP_EXPONENT + PNG_FP_SAW_DOT:
+ goto PNG_FP_End; */
+
+ case PNG_FP_EXPONENT + PNG_FP_SAW_DIGIT:
+ png_fp_add(state, PNG_FP_SAW_DIGIT | PNG_FP_WAS_VALID);
+
+ break;
+
+ /* case PNG_FP_EXPONEXT + PNG_FP_SAW_E:
+ goto PNG_FP_End; */
+
+ default: goto PNG_FP_End; /* I.e. break 2 */
+ }
+
+ /* The character seems ok, continue. */
+ ++i;
+ }
+
+PNG_FP_End:
+ /* Here at the end, update the state and return the correct
+ * return code.
+ */
+ *statep = state;
+ *whereami = i;
+
+ return (state & PNG_FP_SAW_DIGIT) != 0;
+}
+
+
+/* The same but for a complete string. */
+int
+png_check_fp_string(png_const_charp string, png_size_t size)
+{
+ int state=0;
+ png_size_t char_index=0;
+
+ if (png_check_fp_number(string, size, &state, &char_index) != 0 &&
+ (char_index == size || string[char_index] == 0))
+ return state /* must be non-zero - see above */;
+
+ return 0; /* i.e. fail */
+}
+#endif /* pCAL || sCAL */
+
+#ifdef PNG_sCAL_SUPPORTED
+# ifdef PNG_FLOATING_POINT_SUPPORTED
+/* Utility used below - a simple accurate power of ten from an integral
+ * exponent.
+ */
+static double
+png_pow10(int power)
+{
+ int recip = 0;
+ double d = 1;
+
+ /* Handle negative exponent with a reciprocal at the end because
+ * 10 is exact whereas .1 is inexact in base 2
+ */
+ if (power < 0)
+ {
+ if (power < DBL_MIN_10_EXP) return 0;
+ recip = 1, power = -power;
+ }
+
+ if (power > 0)
+ {
+ /* Decompose power bitwise. */
+ double mult = 10;
+ do
+ {
+ if (power & 1) d *= mult;
+ mult *= mult;
+ power >>= 1;
+ }
+ while (power > 0);
+
+ if (recip != 0) d = 1/d;
+ }
+ /* else power is 0 and d is 1 */
+
+ return d;
+}
+
+/* Function to format a floating point value in ASCII with a given
+ * precision.
+ */
+void /* PRIVATE */
+png_ascii_from_fp(png_const_structrp png_ptr, png_charp ascii, png_size_t size,
+ double fp, unsigned int precision)
+{
+ /* We use standard functions from math.h, but not printf because
+ * that would require stdio. The caller must supply a buffer of
+ * sufficient size or we will png_error. The tests on size and
+ * the space in ascii[] consumed are indicated below.
+ */
+ if (precision < 1)
+ precision = DBL_DIG;
+
+ /* Enforce the limit of the implementation precision too. */
+ if (precision > DBL_DIG+1)
+ precision = DBL_DIG+1;
+
+ /* Basic sanity checks */
+ if (size >= precision+5) /* See the requirements below. */
+ {
+ if (fp < 0)
+ {
+ fp = -fp;
+ *ascii++ = 45; /* '-' PLUS 1 TOTAL 1 */
+ --size;
+ }
+
+ if (fp >= DBL_MIN && fp <= DBL_MAX)
+ {
+ int exp_b10; /* A base 10 exponent */
+ double base; /* 10^exp_b10 */
+
+ /* First extract a base 10 exponent of the number,
+ * the calculation below rounds down when converting
+ * from base 2 to base 10 (multiply by log10(2) -
+ * 0.3010, but 77/256 is 0.3008, so exp_b10 needs to
+ * be increased. Note that the arithmetic shift
+ * performs a floor() unlike C arithmetic - using a
+ * C multiply would break the following for negative
+ * exponents.
+ */
+ (void)frexp(fp, &exp_b10); /* exponent to base 2 */
+
+ exp_b10 = (exp_b10 * 77) >> 8; /* <= exponent to base 10 */
+
+ /* Avoid underflow here. */
+ base = png_pow10(exp_b10); /* May underflow */
+
+ while (base < DBL_MIN || base < fp)
+ {
+ /* And this may overflow. */
+ double test = png_pow10(exp_b10+1);
+
+ if (test <= DBL_MAX)
+ ++exp_b10, base = test;
+
+ else
+ break;
+ }
+
+ /* Normalize fp and correct exp_b10, after this fp is in the
+ * range [.1,1) and exp_b10 is both the exponent and the digit
+ * *before* which the decimal point should be inserted
+ * (starting with 0 for the first digit). Note that this
+ * works even if 10^exp_b10 is out of range because of the
+ * test on DBL_MAX above.
+ */
+ fp /= base;
+ while (fp >= 1) fp /= 10, ++exp_b10;
+
+ /* Because of the code above fp may, at this point, be
+ * less than .1, this is ok because the code below can
+ * handle the leading zeros this generates, so no attempt
+ * is made to correct that here.
+ */
+
+ {
+ int czero, clead, cdigits;
+ char exponent[10];
+
+ /* Allow up to two leading zeros - this will not lengthen
+ * the number compared to using E-n.
+ */
+ if (exp_b10 < 0 && exp_b10 > -3) /* PLUS 3 TOTAL 4 */
+ {
+ czero = -exp_b10; /* PLUS 2 digits: TOTAL 3 */
+ exp_b10 = 0; /* Dot added below before first output. */
+ }
+ else
+ czero = 0; /* No zeros to add */
+
+ /* Generate the digit list, stripping trailing zeros and
+ * inserting a '.' before a digit if the exponent is 0.
+ */
+ clead = czero; /* Count of leading zeros */
+ cdigits = 0; /* Count of digits in list. */
+
+ do
+ {
+ double d;
+
+ fp *= 10;
+ /* Use modf here, not floor and subtract, so that
+ * the separation is done in one step. At the end
+ * of the loop don't break the number into parts so
+ * that the final digit is rounded.
+ */
+ if (cdigits+czero-clead+1 < (int)precision)
+ fp = modf(fp, &d);
+
+ else
+ {
+ d = floor(fp + .5);
+
+ if (d > 9)
+ {
+ /* Rounding up to 10, handle that here. */
+ if (czero > 0)
+ {
+ --czero, d = 1;
+ if (cdigits == 0) --clead;
+ }
+ else
+ {
+ while (cdigits > 0 && d > 9)
+ {
+ int ch = *--ascii;
+
+ if (exp_b10 != (-1))
+ ++exp_b10;
+
+ else if (ch == 46)
+ {
+ ch = *--ascii, ++size;
+ /* Advance exp_b10 to '1', so that the
+ * decimal point happens after the
+ * previous digit.
+ */
+ exp_b10 = 1;
+ }
+
+ --cdigits;
+ d = ch - 47; /* I.e. 1+(ch-48) */
+ }
+
+ /* Did we reach the beginning? If so adjust the
+ * exponent but take into account the leading
+ * decimal point.
+ */
+ if (d > 9) /* cdigits == 0 */
+ {
+ if (exp_b10 == (-1))
+ {
+ /* Leading decimal point (plus zeros?), if
+ * we lose the decimal point here it must
+ * be reentered below.
+ */
+ int ch = *--ascii;
+
+ if (ch == 46)
+ ++size, exp_b10 = 1;
+
+ /* Else lost a leading zero, so 'exp_b10' is
+ * still ok at (-1)
+ */
+ }
+ else
+ ++exp_b10;
+
+ /* In all cases we output a '1' */
+ d = 1;
+ }
+ }
+ }
+ fp = 0; /* Guarantees termination below. */
+ }
+
+ if (d == 0)
+ {
+ ++czero;
+ if (cdigits == 0) ++clead;
+ }
+ else
+ {
+ /* Included embedded zeros in the digit count. */
+ cdigits += czero - clead;
+ clead = 0;
+
+ while (czero > 0)
+ {
+ /* exp_b10 == (-1) means we just output the decimal
+ * place - after the DP don't adjust 'exp_b10' any
+ * more!
+ */
+ if (exp_b10 != (-1))
+ {
+ if (exp_b10 == 0) *ascii++ = 46, --size;
+ /* PLUS 1: TOTAL 4 */
+ --exp_b10;
+ }
+ *ascii++ = 48, --czero;
+ }
+
+ if (exp_b10 != (-1))
+ {
+ if (exp_b10 == 0)
+ *ascii++ = 46, --size; /* counted above */
+
+ --exp_b10;
+ }
+ *ascii++ = (char)(48 + (int)d), ++cdigits;
+ }
+ }
+ while (cdigits+czero-clead < (int)precision && fp > DBL_MIN);
+
+ /* The total output count (max) is now 4+precision */
+
+ /* Check for an exponent, if we don't need one we are
+ * done and just need to terminate the string. At
+ * this point exp_b10==(-1) is effectively if flag - it got
+ * to '-1' because of the decrement after outputting
+ * the decimal point above (the exponent required is
+ * *not* -1!)
+ */
+ if (exp_b10 >= (-1) && exp_b10 <= 2)
+ {
+ /* The following only happens if we didn't output the
+ * leading zeros above for negative exponent, so this
+ * doesn't add to the digit requirement. Note that the
+ * two zeros here can only be output if the two leading
+ * zeros were *not* output, so this doesn't increase
+ * the output count.
+ */
+ while (--exp_b10 >= 0) *ascii++ = 48;
+
+ *ascii = 0;
+
+ /* Total buffer requirement (including the '\0') is
+ * 5+precision - see check at the start.
+ */
+ return;
+ }
+
+ /* Here if an exponent is required, adjust size for
+ * the digits we output but did not count. The total
+ * digit output here so far is at most 1+precision - no
+ * decimal point and no leading or trailing zeros have
+ * been output.
+ */
+ size -= cdigits;
+
+ *ascii++ = 69, --size; /* 'E': PLUS 1 TOTAL 2+precision */
+
+ /* The following use of an unsigned temporary avoids ambiguities in
+ * the signed arithmetic on exp_b10 and permits GCC at least to do
+ * better optimization.
+ */
+ {
+ unsigned int uexp_b10;
+
+ if (exp_b10 < 0)
+ {
+ *ascii++ = 45, --size; /* '-': PLUS 1 TOTAL 3+precision */
+ uexp_b10 = -exp_b10;
+ }
+
+ else
+ uexp_b10 = exp_b10;
+
+ cdigits = 0;
+
+ while (uexp_b10 > 0)
+ {
+ exponent[cdigits++] = (char)(48 + uexp_b10 % 10);
+ uexp_b10 /= 10;
+ }
+ }
+
+ /* Need another size check here for the exponent digits, so
+ * this need not be considered above.
+ */
+ if ((int)size > cdigits)
+ {
+ while (cdigits > 0) *ascii++ = exponent[--cdigits];
+
+ *ascii = 0;
+
+ return;
+ }
+ }
+ }
+ else if (!(fp >= DBL_MIN))
+ {
+ *ascii++ = 48; /* '0' */
+ *ascii = 0;
+ return;
+ }
+ else
+ {
+ *ascii++ = 105; /* 'i' */
+ *ascii++ = 110; /* 'n' */
+ *ascii++ = 102; /* 'f' */
+ *ascii = 0;
+ return;
+ }
+ }
+
+ /* Here on buffer too small. */
+ png_error(png_ptr, "ASCII conversion buffer too small");
+}
+
+# endif /* FLOATING_POINT */
+
+# ifdef PNG_FIXED_POINT_SUPPORTED
+/* Function to format a fixed point value in ASCII.
+ */
+void /* PRIVATE */
+png_ascii_from_fixed(png_const_structrp png_ptr, png_charp ascii,
+ png_size_t size, png_fixed_point fp)
+{
+ /* Require space for 10 decimal digits, a decimal point, a minus sign and a
+ * trailing \0, 13 characters:
+ */
+ if (size > 12)
+ {
+ png_uint_32 num;
+
+ /* Avoid overflow here on the minimum integer. */
+ if (fp < 0)
+ *ascii++ = 45, --size, num = -fp;
+ else
+ num = fp;
+
+ if (num <= 0x80000000) /* else overflowed */
+ {
+ unsigned int ndigits = 0, first = 16 /* flag value */;
+ char digits[10];
+
+ while (num)
+ {
+ /* Split the low digit off num: */
+ unsigned int tmp = num/10;
+ num -= tmp*10;
+ digits[ndigits++] = (char)(48 + num);
+ /* Record the first non-zero digit, note that this is a number
+ * starting at 1, it's not actually the array index.
+ */
+ if (first == 16 && num > 0)
+ first = ndigits;
+ num = tmp;
+ }
+
+ if (ndigits > 0)
+ {
+ while (ndigits > 5) *ascii++ = digits[--ndigits];
+ /* The remaining digits are fractional digits, ndigits is '5' or
+ * smaller at this point. It is certainly not zero. Check for a
+ * non-zero fractional digit:
+ */
+ if (first <= 5)
+ {
+ unsigned int i;
+ *ascii++ = 46; /* decimal point */
+ /* ndigits may be <5 for small numbers, output leading zeros
+ * then ndigits digits to first:
+ */
+ i = 5;
+ while (ndigits < i) *ascii++ = 48, --i;
+ while (ndigits >= first) *ascii++ = digits[--ndigits];
+ /* Don't output the trailing zeros! */
+ }
+ }
+ else
+ *ascii++ = 48;
+
+ /* And null terminate the string: */
+ *ascii = 0;
+ return;
+ }
+ }
+
+ /* Here on buffer too small. */
+ png_error(png_ptr, "ASCII conversion buffer too small");
+}
+# endif /* FIXED_POINT */
+#endif /* SCAL */
+
+#if defined(PNG_FLOATING_POINT_SUPPORTED) && \
+ !defined(PNG_FIXED_POINT_MACRO_SUPPORTED) && \
+ (defined(PNG_gAMA_SUPPORTED) || defined(PNG_cHRM_SUPPORTED) || \
+ defined(PNG_sCAL_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED) || \
+ defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)) || \
+ (defined(PNG_sCAL_SUPPORTED) && \
+ defined(PNG_FLOATING_ARITHMETIC_SUPPORTED))
+png_fixed_point
+png_fixed(png_const_structrp png_ptr, double fp, png_const_charp text)
+{
+ double r = floor(100000 * fp + .5);
+
+ if (r > 2147483647. || r < -2147483648.)
+ png_fixed_error(png_ptr, text);
+
+# ifndef PNG_ERROR_TEXT_SUPPORTED
+ PNG_UNUSED(text)
+# endif
+
+ return (png_fixed_point)r;
+}
+#endif
+
+#if defined(PNG_GAMMA_SUPPORTED) || defined(PNG_COLORSPACE_SUPPORTED) ||\
+ defined(PNG_INCH_CONVERSIONS_SUPPORTED) || defined(PNG_READ_pHYs_SUPPORTED)
+/* muldiv functions */
+/* This API takes signed arguments and rounds the result to the nearest
+ * integer (or, for a fixed point number - the standard argument - to
+ * the nearest .00001). Overflow and divide by zero are signalled in
+ * the result, a boolean - true on success, false on overflow.
+ */
+int
+png_muldiv(png_fixed_point_p res, png_fixed_point a, png_int_32 times,
+ png_int_32 divisor)
+{
+ /* Return a * times / divisor, rounded. */
+ if (divisor != 0)
+ {
+ if (a == 0 || times == 0)
+ {
+ *res = 0;
+ return 1;
+ }
+ else
+ {
+#ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED
+ double r = a;
+ r *= times;
+ r /= divisor;
+ r = floor(r+.5);
+
+ /* A png_fixed_point is a 32-bit integer. */
+ if (r <= 2147483647. && r >= -2147483648.)
+ {
+ *res = (png_fixed_point)r;
+ return 1;
+ }
+#else
+ int negative = 0;
+ png_uint_32 A, T, D;
+ png_uint_32 s16, s32, s00;
+
+ if (a < 0)
+ negative = 1, A = -a;
+ else
+ A = a;
+
+ if (times < 0)
+ negative = !negative, T = -times;
+ else
+ T = times;
+
+ if (divisor < 0)
+ negative = !negative, D = -divisor;
+ else
+ D = divisor;
+
+ /* Following can't overflow because the arguments only
+ * have 31 bits each, however the result may be 32 bits.
+ */
+ s16 = (A >> 16) * (T & 0xffff) +
+ (A & 0xffff) * (T >> 16);
+ /* Can't overflow because the a*times bit is only 30
+ * bits at most.
+ */
+ s32 = (A >> 16) * (T >> 16) + (s16 >> 16);
+ s00 = (A & 0xffff) * (T & 0xffff);
+
+ s16 = (s16 & 0xffff) << 16;
+ s00 += s16;
+
+ if (s00 < s16)
+ ++s32; /* carry */
+
+ if (s32 < D) /* else overflow */
+ {
+ /* s32.s00 is now the 64-bit product, do a standard
+ * division, we know that s32 < D, so the maximum
+ * required shift is 31.
+ */
+ int bitshift = 32;
+ png_fixed_point result = 0; /* NOTE: signed */
+
+ while (--bitshift >= 0)
+ {
+ png_uint_32 d32, d00;
+
+ if (bitshift > 0)
+ d32 = D >> (32-bitshift), d00 = D << bitshift;
+
+ else
+ d32 = 0, d00 = D;
+
+ if (s32 > d32)
+ {
+ if (s00 < d00) --s32; /* carry */
+ s32 -= d32, s00 -= d00, result += 1<<bitshift;
+ }
+
+ else
+ if (s32 == d32 && s00 >= d00)
+ s32 = 0, s00 -= d00, result += 1<<bitshift;
+ }
+
+ /* Handle the rounding. */
+ if (s00 >= (D >> 1))
+ ++result;
+
+ if (negative != 0)
+ result = -result;
+
+ /* Check for overflow. */
+ if ((negative != 0 && result <= 0) ||
+ (negative == 0 && result >= 0))
+ {
+ *res = result;
+ return 1;
+ }
+ }
+#endif
+ }
+ }
+
+ return 0;
+}
+#endif /* READ_GAMMA || INCH_CONVERSIONS */
+
+#if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_INCH_CONVERSIONS_SUPPORTED)
+/* The following is for when the caller doesn't much care about the
+ * result.
+ */
+png_fixed_point
+png_muldiv_warn(png_const_structrp png_ptr, png_fixed_point a, png_int_32 times,
+ png_int_32 divisor)
+{
+ png_fixed_point result;
+
+ if (png_muldiv(&result, a, times, divisor) != 0)
+ return result;
+
+ png_warning(png_ptr, "fixed point overflow ignored");
+ return 0;
+}
+#endif
+
+#ifdef PNG_GAMMA_SUPPORTED /* more fixed point functions for gamma */
+/* Calculate a reciprocal, return 0 on div-by-zero or overflow. */
+png_fixed_point
+png_reciprocal(png_fixed_point a)
+{
+#ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED
+ double r = floor(1E10/a+.5);
+
+ if (r <= 2147483647. && r >= -2147483648.)
+ return (png_fixed_point)r;
+#else
+ png_fixed_point res;
+
+ if (png_muldiv(&res, 100000, 100000, a) != 0)
+ return res;
+#endif
+
+ return 0; /* error/overflow */
+}
+
+/* This is the shared test on whether a gamma value is 'significant' - whether
+ * it is worth doing gamma correction.
+ */
+int /* PRIVATE */
+png_gamma_significant(png_fixed_point gamma_val)
+{
+ return gamma_val < PNG_FP_1 - PNG_GAMMA_THRESHOLD_FIXED ||
+ gamma_val > PNG_FP_1 + PNG_GAMMA_THRESHOLD_FIXED;
+}
+#endif
+
+#ifdef PNG_READ_GAMMA_SUPPORTED
+#ifdef PNG_16BIT_SUPPORTED
+/* A local convenience routine. */
+static png_fixed_point
+png_product2(png_fixed_point a, png_fixed_point b)
+{
+ /* The required result is 1/a * 1/b; the following preserves accuracy. */
+#ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED
+ double r = a * 1E-5;
+ r *= b;
+ r = floor(r+.5);
+
+ if (r <= 2147483647. && r >= -2147483648.)
+ return (png_fixed_point)r;
+#else
+ png_fixed_point res;
+
+ if (png_muldiv(&res, a, b, 100000) != 0)
+ return res;
+#endif
+
+ return 0; /* overflow */
+}
+#endif /* 16BIT */
+
+/* The inverse of the above. */
+png_fixed_point
+png_reciprocal2(png_fixed_point a, png_fixed_point b)
+{
+ /* The required result is 1/a * 1/b; the following preserves accuracy. */
+#ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED
+ if (a != 0 && b != 0)
+ {
+ double r = 1E15/a;
+ r /= b;
+ r = floor(r+.5);
+
+ if (r <= 2147483647. && r >= -2147483648.)
+ return (png_fixed_point)r;
+ }
+#else
+ /* This may overflow because the range of png_fixed_point isn't symmetric,
+ * but this API is only used for the product of file and screen gamma so it
+ * doesn't matter that the smallest number it can produce is 1/21474, not
+ * 1/100000
+ */
+ png_fixed_point res = png_product2(a, b);
+
+ if (res != 0)
+ return png_reciprocal(res);
+#endif
+
+ return 0; /* overflow */
+}
+#endif /* READ_GAMMA */
+
+#ifdef PNG_READ_GAMMA_SUPPORTED /* gamma table code */
+#ifndef PNG_FLOATING_ARITHMETIC_SUPPORTED
+/* Fixed point gamma.
+ *
+ * The code to calculate the tables used below can be found in the shell script
+ * contrib/tools/intgamma.sh
+ *
+ * To calculate gamma this code implements fast log() and exp() calls using only
+ * fixed point arithmetic. This code has sufficient precision for either 8-bit
+ * or 16-bit sample values.
+ *
+ * The tables used here were calculated using simple 'bc' programs, but C double
+ * precision floating point arithmetic would work fine.
+ *
+ * 8-bit log table
+ * This is a table of -log(value/255)/log(2) for 'value' in the range 128 to
+ * 255, so it's the base 2 logarithm of a normalized 8-bit floating point
+ * mantissa. The numbers are 32-bit fractions.
+ */
+static const png_uint_32
+png_8bit_l2[128] =
+{
+ 4270715492U, 4222494797U, 4174646467U, 4127164793U, 4080044201U, 4033279239U,
+ 3986864580U, 3940795015U, 3895065449U, 3849670902U, 3804606499U, 3759867474U,
+ 3715449162U, 3671346997U, 3627556511U, 3584073329U, 3540893168U, 3498011834U,
+ 3455425220U, 3413129301U, 3371120137U, 3329393864U, 3287946700U, 3246774933U,
+ 3205874930U, 3165243125U, 3124876025U, 3084770202U, 3044922296U, 3005329011U,
+ 2965987113U, 2926893432U, 2888044853U, 2849438323U, 2811070844U, 2772939474U,
+ 2735041326U, 2697373562U, 2659933400U, 2622718104U, 2585724991U, 2548951424U,
+ 2512394810U, 2476052606U, 2439922311U, 2404001468U, 2368287663U, 2332778523U,
+ 2297471715U, 2262364947U, 2227455964U, 2192742551U, 2158222529U, 2123893754U,
+ 2089754119U, 2055801552U, 2022034013U, 1988449497U, 1955046031U, 1921821672U,
+ 1888774511U, 1855902668U, 1823204291U, 1790677560U, 1758320682U, 1726131893U,
+ 1694109454U, 1662251657U, 1630556815U, 1599023271U, 1567649391U, 1536433567U,
+ 1505374214U, 1474469770U, 1443718700U, 1413119487U, 1382670639U, 1352370686U,
+ 1322218179U, 1292211689U, 1262349810U, 1232631153U, 1203054352U, 1173618059U,
+ 1144320946U, 1115161701U, 1086139034U, 1057251672U, 1028498358U, 999877854U,
+ 971388940U, 943030410U, 914801076U, 886699767U, 858725327U, 830876614U,
+ 803152505U, 775551890U, 748073672U, 720716771U, 693480120U, 666362667U,
+ 639363374U, 612481215U, 585715177U, 559064263U, 532527486U, 506103872U,
+ 479792461U, 453592303U, 427502463U, 401522014U, 375650043U, 349885648U,
+ 324227938U, 298676034U, 273229066U, 247886176U, 222646516U, 197509248U,
+ 172473545U, 147538590U, 122703574U, 97967701U, 73330182U, 48790236U,
+ 24347096U, 0U
+
+#if 0
+ /* The following are the values for 16-bit tables - these work fine for the
+ * 8-bit conversions but produce very slightly larger errors in the 16-bit
+ * log (about 1.2 as opposed to 0.7 absolute error in the final value). To
+ * use these all the shifts below must be adjusted appropriately.
+ */
+ 65166, 64430, 63700, 62976, 62257, 61543, 60835, 60132, 59434, 58741, 58054,
+ 57371, 56693, 56020, 55352, 54689, 54030, 53375, 52726, 52080, 51439, 50803,
+ 50170, 49542, 48918, 48298, 47682, 47070, 46462, 45858, 45257, 44661, 44068,
+ 43479, 42894, 42312, 41733, 41159, 40587, 40020, 39455, 38894, 38336, 37782,
+ 37230, 36682, 36137, 35595, 35057, 34521, 33988, 33459, 32932, 32408, 31887,
+ 31369, 30854, 30341, 29832, 29325, 28820, 28319, 27820, 27324, 26830, 26339,
+ 25850, 25364, 24880, 24399, 23920, 23444, 22970, 22499, 22029, 21562, 21098,
+ 20636, 20175, 19718, 19262, 18808, 18357, 17908, 17461, 17016, 16573, 16132,
+ 15694, 15257, 14822, 14390, 13959, 13530, 13103, 12678, 12255, 11834, 11415,
+ 10997, 10582, 10168, 9756, 9346, 8937, 8531, 8126, 7723, 7321, 6921, 6523,
+ 6127, 5732, 5339, 4947, 4557, 4169, 3782, 3397, 3014, 2632, 2251, 1872, 1495,
+ 1119, 744, 372
+#endif
+};
+
+static png_int_32
+png_log8bit(unsigned int x)
+{
+ unsigned int lg2 = 0;
+ /* Each time 'x' is multiplied by 2, 1 must be subtracted off the final log,
+ * because the log is actually negate that means adding 1. The final
+ * returned value thus has the range 0 (for 255 input) to 7.994 (for 1
+ * input), return -1 for the overflow (log 0) case, - so the result is
+ * always at most 19 bits.
+ */
+ if ((x &= 0xff) == 0)
+ return -1;
+
+ if ((x & 0xf0) == 0)
+ lg2 = 4, x <<= 4;
+
+ if ((x & 0xc0) == 0)
+ lg2 += 2, x <<= 2;
+
+ if ((x & 0x80) == 0)
+ lg2 += 1, x <<= 1;
+
+ /* result is at most 19 bits, so this cast is safe: */
+ return (png_int_32)((lg2 << 16) + ((png_8bit_l2[x-128]+32768)>>16));
+}
+
+/* The above gives exact (to 16 binary places) log2 values for 8-bit images,
+ * for 16-bit images we use the most significant 8 bits of the 16-bit value to
+ * get an approximation then multiply the approximation by a correction factor
+ * determined by the remaining up to 8 bits. This requires an additional step
+ * in the 16-bit case.
+ *
+ * We want log2(value/65535), we have log2(v'/255), where:
+ *
+ * value = v' * 256 + v''
+ * = v' * f
+ *
+ * So f is value/v', which is equal to (256+v''/v') since v' is in the range 128
+ * to 255 and v'' is in the range 0 to 255 f will be in the range 256 to less
+ * than 258. The final factor also needs to correct for the fact that our 8-bit
+ * value is scaled by 255, whereas the 16-bit values must be scaled by 65535.
+ *
+ * This gives a final formula using a calculated value 'x' which is value/v' and
+ * scaling by 65536 to match the above table:
+ *
+ * log2(x/257) * 65536
+ *
+ * Since these numbers are so close to '1' we can use simple linear
+ * interpolation between the two end values 256/257 (result -368.61) and 258/257
+ * (result 367.179). The values used below are scaled by a further 64 to give
+ * 16-bit precision in the interpolation:
+ *
+ * Start (256): -23591
+ * Zero (257): 0
+ * End (258): 23499
+ */
+#ifdef PNG_16BIT_SUPPORTED
+static png_int_32
+png_log16bit(png_uint_32 x)
+{
+ unsigned int lg2 = 0;
+
+ /* As above, but now the input has 16 bits. */
+ if ((x &= 0xffff) == 0)
+ return -1;
+
+ if ((x & 0xff00) == 0)
+ lg2 = 8, x <<= 8;
+
+ if ((x & 0xf000) == 0)
+ lg2 += 4, x <<= 4;
+
+ if ((x & 0xc000) == 0)
+ lg2 += 2, x <<= 2;
+
+ if ((x & 0x8000) == 0)
+ lg2 += 1, x <<= 1;
+
+ /* Calculate the base logarithm from the top 8 bits as a 28-bit fractional
+ * value.
+ */
+ lg2 <<= 28;
+ lg2 += (png_8bit_l2[(x>>8)-128]+8) >> 4;
+
+ /* Now we need to interpolate the factor, this requires a division by the top
+ * 8 bits. Do this with maximum precision.
+ */
+ x = ((x << 16) + (x >> 9)) / (x >> 8);
+
+ /* Since we divided by the top 8 bits of 'x' there will be a '1' at 1<<24,
+ * the value at 1<<16 (ignoring this) will be 0 or 1; this gives us exactly
+ * 16 bits to interpolate to get the low bits of the result. Round the
+ * answer. Note that the end point values are scaled by 64 to retain overall
+ * precision and that 'lg2' is current scaled by an extra 12 bits, so adjust
+ * the overall scaling by 6-12. Round at every step.
+ */
+ x -= 1U << 24;
+
+ if (x <= 65536U) /* <= '257' */
+ lg2 += ((23591U * (65536U-x)) + (1U << (16+6-12-1))) >> (16+6-12);
+
+ else
+ lg2 -= ((23499U * (x-65536U)) + (1U << (16+6-12-1))) >> (16+6-12);
+
+ /* Safe, because the result can't have more than 20 bits: */
+ return (png_int_32)((lg2 + 2048) >> 12);
+}
+#endif /* 16BIT */
+
+/* The 'exp()' case must invert the above, taking a 20-bit fixed point
+ * logarithmic value and returning a 16 or 8-bit number as appropriate. In
+ * each case only the low 16 bits are relevant - the fraction - since the
+ * integer bits (the top 4) simply determine a shift.
+ *
+ * The worst case is the 16-bit distinction between 65535 and 65534. This
+ * requires perhaps spurious accuracy in the decoding of the logarithm to
+ * distinguish log2(65535/65534.5) - 10^-5 or 17 bits. There is little chance
+ * of getting this accuracy in practice.
+ *
+ * To deal with this the following exp() function works out the exponent of the
+ * frational part of the logarithm by using an accurate 32-bit value from the
+ * top four fractional bits then multiplying in the remaining bits.
+ */
+static const png_uint_32
+png_32bit_exp[16] =
+{
+ /* NOTE: the first entry is deliberately set to the maximum 32-bit value. */
+ 4294967295U, 4112874773U, 3938502376U, 3771522796U, 3611622603U, 3458501653U,
+ 3311872529U, 3171459999U, 3037000500U, 2908241642U, 2784941738U, 2666869345U,
+ 2553802834U, 2445529972U, 2341847524U, 2242560872U
+};
+
+/* Adjustment table; provided to explain the numbers in the code below. */
+#if 0
+for (i=11;i>=0;--i){ print i, " ", (1 - e(-(2^i)/65536*l(2))) * 2^(32-i), "\n"}
+ 11 44937.64284865548751208448
+ 10 45180.98734845585101160448
+ 9 45303.31936980687359311872
+ 8 45364.65110595323018870784
+ 7 45395.35850361789624614912
+ 6 45410.72259715102037508096
+ 5 45418.40724413220722311168
+ 4 45422.25021786898173001728
+ 3 45424.17186732298419044352
+ 2 45425.13273269940811464704
+ 1 45425.61317555035558641664
+ 0 45425.85339951654943850496
+#endif
+
+static png_uint_32
+png_exp(png_fixed_point x)
+{
+ if (x > 0 && x <= 0xfffff) /* Else overflow or zero (underflow) */
+ {
+ /* Obtain a 4-bit approximation */
+ png_uint_32 e = png_32bit_exp[(x >> 12) & 0xf];
+
+ /* Incorporate the low 12 bits - these decrease the returned value by
+ * multiplying by a number less than 1 if the bit is set. The multiplier
+ * is determined by the above table and the shift. Notice that the values
+ * converge on 45426 and this is used to allow linear interpolation of the
+ * low bits.
+ */
+ if (x & 0x800)
+ e -= (((e >> 16) * 44938U) + 16U) >> 5;
+
+ if (x & 0x400)
+ e -= (((e >> 16) * 45181U) + 32U) >> 6;
+
+ if (x & 0x200)
+ e -= (((e >> 16) * 45303U) + 64U) >> 7;
+
+ if (x & 0x100)
+ e -= (((e >> 16) * 45365U) + 128U) >> 8;
+
+ if (x & 0x080)
+ e -= (((e >> 16) * 45395U) + 256U) >> 9;
+
+ if (x & 0x040)
+ e -= (((e >> 16) * 45410U) + 512U) >> 10;
+
+ /* And handle the low 6 bits in a single block. */
+ e -= (((e >> 16) * 355U * (x & 0x3fU)) + 256U) >> 9;
+
+ /* Handle the upper bits of x. */
+ e >>= x >> 16;
+ return e;
+ }
+
+ /* Check for overflow */
+ if (x <= 0)
+ return png_32bit_exp[0];
+
+ /* Else underflow */
+ return 0;
+}
+
+static png_byte
+png_exp8bit(png_fixed_point lg2)
+{
+ /* Get a 32-bit value: */
+ png_uint_32 x = png_exp(lg2);
+
+ /* Convert the 32-bit value to 0..255 by multiplying by 256-1. Note that the
+ * second, rounding, step can't overflow because of the first, subtraction,
+ * step.
+ */
+ x -= x >> 8;
+ return (png_byte)(((x + 0x7fffffU) >> 24) & 0xff);
+}
+
+#ifdef PNG_16BIT_SUPPORTED
+static png_uint_16
+png_exp16bit(png_fixed_point lg2)
+{
+ /* Get a 32-bit value: */
+ png_uint_32 x = png_exp(lg2);
+
+ /* Convert the 32-bit value to 0..65535 by multiplying by 65536-1: */
+ x -= x >> 16;
+ return (png_uint_16)((x + 32767U) >> 16);
+}
+#endif /* 16BIT */
+#endif /* FLOATING_ARITHMETIC */
+
+png_byte
+png_gamma_8bit_correct(unsigned int value, png_fixed_point gamma_val)
+{
+ if (value > 0 && value < 255)
+ {
+# ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED
+ /* 'value' is unsigned, ANSI-C90 requires the compiler to correctly
+ * convert this to a floating point value. This includes values that
+ * would overflow if 'value' were to be converted to 'int'.
+ *
+ * Apparently GCC, however, does an intermediate conversion to (int)
+ * on some (ARM) but not all (x86) platforms, possibly because of
+ * hardware FP limitations. (E.g. if the hardware conversion always
+ * assumes the integer register contains a signed value.) This results
+ * in ANSI-C undefined behavior for large values.
+ *
+ * Other implementations on the same machine might actually be ANSI-C90
+ * conformant and therefore compile spurious extra code for the large
+ * values.
+ *
+ * We can be reasonably sure that an unsigned to float conversion
+ * won't be faster than an int to float one. Therefore this code
+ * assumes responsibility for the undefined behavior, which it knows
+ * can't happen because of the check above.
+ *
+ * Note the argument to this routine is an (unsigned int) because, on
+ * 16-bit platforms, it is assigned a value which might be out of
+ * range for an (int); that would result in undefined behavior in the
+ * caller if the *argument* ('value') were to be declared (int).
+ */
+ double r = floor(255*pow((int)/*SAFE*/value/255.,gamma_val*.00001)+.5);
+ return (png_byte)r;
+# else
+ png_int_32 lg2 = png_log8bit(value);
+ png_fixed_point res;
+
+ if (png_muldiv(&res, gamma_val, lg2, PNG_FP_1) != 0)
+ return png_exp8bit(res);
+
+ /* Overflow. */
+ value = 0;
+# endif
+ }
+
+ return (png_byte)(value & 0xff);
+}
+
+#ifdef PNG_16BIT_SUPPORTED
+png_uint_16
+png_gamma_16bit_correct(unsigned int value, png_fixed_point gamma_val)
+{
+ if (value > 0 && value < 65535)
+ {
+# ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED
+ /* The same (unsigned int)->(double) constraints apply here as above,
+ * however in this case the (unsigned int) to (int) conversion can
+ * overflow on an ANSI-C90 compliant system so the cast needs to ensure
+ * that this is not possible.
+ */
+ double r = floor(65535*pow((png_int_32)value/65535.,
+ gamma_val*.00001)+.5);
+ return (png_uint_16)r;
+# else
+ png_int_32 lg2 = png_log16bit(value);
+ png_fixed_point res;
+
+ if (png_muldiv(&res, gamma_val, lg2, PNG_FP_1) != 0)
+ return png_exp16bit(res);
+
+ /* Overflow. */
+ value = 0;
+# endif
+ }
+
+ return (png_uint_16)value;
+}
+#endif /* 16BIT */
+
+/* This does the right thing based on the bit_depth field of the
+ * png_struct, interpreting values as 8-bit or 16-bit. While the result
+ * is nominally a 16-bit value if bit depth is 8 then the result is
+ * 8-bit (as are the arguments.)
+ */
+png_uint_16 /* PRIVATE */
+png_gamma_correct(png_structrp png_ptr, unsigned int value,
+ png_fixed_point gamma_val)
+{
+ if (png_ptr->bit_depth == 8)
+ return png_gamma_8bit_correct(value, gamma_val);
+
+#ifdef PNG_16BIT_SUPPORTED
+ else
+ return png_gamma_16bit_correct(value, gamma_val);
+#else
+ /* should not reach this */
+ return 0;
+#endif /* 16BIT */
+}
+
+#ifdef PNG_16BIT_SUPPORTED
+/* Internal function to build a single 16-bit table - the table consists of
+ * 'num' 256 entry subtables, where 'num' is determined by 'shift' - the amount
+ * to shift the input values right (or 16-number_of_signifiant_bits).
+ *
+ * The caller is responsible for ensuring that the table gets cleaned up on
+ * png_error (i.e. if one of the mallocs below fails) - i.e. the *table argument
+ * should be somewhere that will be cleaned.
+ */
+static void
+png_build_16bit_table(png_structrp png_ptr, png_uint_16pp *ptable,
+ PNG_CONST unsigned int shift, PNG_CONST png_fixed_point gamma_val)
+{
+ /* Various values derived from 'shift': */
+ PNG_CONST unsigned int num = 1U << (8U - shift);
+#ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED
+ /* CSE the division and work round wacky GCC warnings (see the comments
+ * in png_gamma_8bit_correct for where these come from.)
+ */
+ PNG_CONST double fmax = 1./(((png_int_32)1 << (16U - shift))-1);
+#endif
+ PNG_CONST unsigned int max = (1U << (16U - shift))-1U;
+ PNG_CONST unsigned int max_by_2 = 1U << (15U-shift);
+ unsigned int i;
+
+ png_uint_16pp table = *ptable =
+ (png_uint_16pp)png_calloc(png_ptr, num * (sizeof (png_uint_16p)));
+
+ for (i = 0; i < num; i++)
+ {
+ png_uint_16p sub_table = table[i] =
+ (png_uint_16p)png_malloc(png_ptr, 256 * (sizeof (png_uint_16)));
+
+ /* The 'threshold' test is repeated here because it can arise for one of
+ * the 16-bit tables even if the others don't hit it.
+ */
+ if (png_gamma_significant(gamma_val) != 0)
+ {
+ /* The old code would overflow at the end and this would cause the
+ * 'pow' function to return a result >1, resulting in an
+ * arithmetic error. This code follows the spec exactly; ig is
+ * the recovered input sample, it always has 8-16 bits.
+ *
+ * We want input * 65535/max, rounded, the arithmetic fits in 32
+ * bits (unsigned) so long as max <= 32767.
+ */
+ unsigned int j;
+ for (j = 0; j < 256; j++)
+ {
+ png_uint_32 ig = (j << (8-shift)) + i;
+# ifdef PNG_FLOATING_ARITHMETIC_SUPPORTED
+ /* Inline the 'max' scaling operation: */
+ /* See png_gamma_8bit_correct for why the cast to (int) is
+ * required here.
+ */
+ double d = floor(65535.*pow(ig*fmax, gamma_val*.00001)+.5);
+ sub_table[j] = (png_uint_16)d;
+# else
+ if (shift != 0)
+ ig = (ig * 65535U + max_by_2)/max;
+
+ sub_table[j] = png_gamma_16bit_correct(ig, gamma_val);
+# endif
+ }
+ }
+ else
+ {
+ /* We must still build a table, but do it the fast way. */
+ unsigned int j;
+
+ for (j = 0; j < 256; j++)
+ {
+ png_uint_32 ig = (j << (8-shift)) + i;
+
+ if (shift != 0)
+ ig = (ig * 65535U + max_by_2)/max;
+
+ sub_table[j] = (png_uint_16)ig;
+ }
+ }
+ }
+}
+
+/* NOTE: this function expects the *inverse* of the overall gamma transformation
+ * required.
+ */
+static void
+png_build_16to8_table(png_structrp png_ptr, png_uint_16pp *ptable,
+ PNG_CONST unsigned int shift, PNG_CONST png_fixed_point gamma_val)
+{
+ PNG_CONST unsigned int num = 1U << (8U - shift);
+ PNG_CONST unsigned int max = (1U << (16U - shift))-1U;
+ unsigned int i;
+ png_uint_32 last;
+
+ png_uint_16pp table = *ptable =
+ (png_uint_16pp)png_calloc(png_ptr, num * (sizeof (png_uint_16p)));
+
+ /* 'num' is the number of tables and also the number of low bits of low
+ * bits of the input 16-bit value used to select a table. Each table is
+ * itself indexed by the high 8 bits of the value.
+ */
+ for (i = 0; i < num; i++)
+ table[i] = (png_uint_16p)png_malloc(png_ptr,
+ 256 * (sizeof (png_uint_16)));
+
+ /* 'gamma_val' is set to the reciprocal of the value calculated above, so
+ * pow(out,g) is an *input* value. 'last' is the last input value set.
+ *
+ * In the loop 'i' is used to find output values. Since the output is
+ * 8-bit there are only 256 possible values. The tables are set up to
+ * select the closest possible output value for each input by finding
+ * the input value at the boundary between each pair of output values
+ * and filling the table up to that boundary with the lower output
+ * value.
+ *
+ * The boundary values are 0.5,1.5..253.5,254.5. Since these are 9-bit
+ * values the code below uses a 16-bit value in i; the values start at
+ * 128.5 (for 0.5) and step by 257, for a total of 254 values (the last
+ * entries are filled with 255). Start i at 128 and fill all 'last'
+ * table entries <= 'max'
+ */
+ last = 0;
+ for (i = 0; i < 255; ++i) /* 8-bit output value */
+ {
+ /* Find the corresponding maximum input value */
+ png_uint_16 out = (png_uint_16)(i * 257U); /* 16-bit output value */
+
+ /* Find the boundary value in 16 bits: */
+ png_uint_32 bound = png_gamma_16bit_correct(out+128U, gamma_val);
+
+ /* Adjust (round) to (16-shift) bits: */
+ bound = (bound * max + 32768U)/65535U + 1U;
+
+ while (last < bound)
+ {
+ table[last & (0xffU >> shift)][last >> (8U - shift)] = out;
+ last++;
+ }
+ }
+
+ /* And fill in the final entries. */
+ while (last < (num << 8))
+ {
+ table[last & (0xff >> shift)][last >> (8U - shift)] = 65535U;
+ last++;
+ }
+}
+#endif /* 16BIT */
+
+/* Build a single 8-bit table: same as the 16-bit case but much simpler (and
+ * typically much faster). Note that libpng currently does no sBIT processing
+ * (apparently contrary to the spec) so a 256-entry table is always generated.
+ */
+static void
+png_build_8bit_table(png_structrp png_ptr, png_bytepp ptable,
+ PNG_CONST png_fixed_point gamma_val)
+{
+ unsigned int i;
+ png_bytep table = *ptable = (png_bytep)png_malloc(png_ptr, 256);
+
+ if (png_gamma_significant(gamma_val) != 0)
+ for (i=0; i<256; i++)
+ table[i] = png_gamma_8bit_correct(i, gamma_val);
+
+ else
+ for (i=0; i<256; ++i)
+ table[i] = (png_byte)(i & 0xff);
+}
+
+/* Used from png_read_destroy and below to release the memory used by the gamma
+ * tables.
+ */
+void /* PRIVATE */
+png_destroy_gamma_table(png_structrp png_ptr)
+{
+ png_free(png_ptr, png_ptr->gamma_table);
+ png_ptr->gamma_table = NULL;
+
+#ifdef PNG_16BIT_SUPPORTED
+ if (png_ptr->gamma_16_table != NULL)
+ {
+ int i;
+ int istop = (1 << (8 - png_ptr->gamma_shift));
+ for (i = 0; i < istop; i++)
+ {
+ png_free(png_ptr, png_ptr->gamma_16_table[i]);
+ }
+ png_free(png_ptr, png_ptr->gamma_16_table);
+ png_ptr->gamma_16_table = NULL;
+ }
+#endif /* 16BIT */
+
+#if defined(PNG_READ_BACKGROUND_SUPPORTED) || \
+ defined(PNG_READ_ALPHA_MODE_SUPPORTED) || \
+ defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)
+ png_free(png_ptr, png_ptr->gamma_from_1);
+ png_ptr->gamma_from_1 = NULL;
+ png_free(png_ptr, png_ptr->gamma_to_1);
+ png_ptr->gamma_to_1 = NULL;
+
+#ifdef PNG_16BIT_SUPPORTED
+ if (png_ptr->gamma_16_from_1 != NULL)
+ {
+ int i;
+ int istop = (1 << (8 - png_ptr->gamma_shift));
+ for (i = 0; i < istop; i++)
+ {
+ png_free(png_ptr, png_ptr->gamma_16_from_1[i]);
+ }
+ png_free(png_ptr, png_ptr->gamma_16_from_1);
+ png_ptr->gamma_16_from_1 = NULL;
+ }
+ if (png_ptr->gamma_16_to_1 != NULL)
+ {
+ int i;
+ int istop = (1 << (8 - png_ptr->gamma_shift));
+ for (i = 0; i < istop; i++)
+ {
+ png_free(png_ptr, png_ptr->gamma_16_to_1[i]);
+ }
+ png_free(png_ptr, png_ptr->gamma_16_to_1);
+ png_ptr->gamma_16_to_1 = NULL;
+ }
+#endif /* 16BIT */
+#endif /* READ_BACKGROUND || READ_ALPHA_MODE || RGB_TO_GRAY */
+}
+
+/* We build the 8- or 16-bit gamma tables here. Note that for 16-bit
+ * tables, we don't make a full table if we are reducing to 8-bit in
+ * the future. Note also how the gamma_16 tables are segmented so that
+ * we don't need to allocate > 64K chunks for a full 16-bit table.
+ */
+void /* PRIVATE */
+png_build_gamma_table(png_structrp png_ptr, int bit_depth)
+{
+ png_debug(1, "in png_build_gamma_table");
+
+ /* Remove any existing table; this copes with multiple calls to
+ * png_read_update_info. The warning is because building the gamma tables
+ * multiple times is a performance hit - it's harmless but the ability to call
+ * png_read_update_info() multiple times is new in 1.5.6 so it seems sensible
+ * to warn if the app introduces such a hit.
+ */
+ if (png_ptr->gamma_table != NULL || png_ptr->gamma_16_table != NULL)
+ {
+ png_warning(png_ptr, "gamma table being rebuilt");
+ png_destroy_gamma_table(png_ptr);
+ }
+
+ if (bit_depth <= 8)
+ {
+ png_build_8bit_table(png_ptr, &png_ptr->gamma_table,
+ png_ptr->screen_gamma > 0 ? png_reciprocal2(png_ptr->colorspace.gamma,
+ png_ptr->screen_gamma) : PNG_FP_1);
+
+#if defined(PNG_READ_BACKGROUND_SUPPORTED) || \
+ defined(PNG_READ_ALPHA_MODE_SUPPORTED) || \
+ defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)
+ if ((png_ptr->transformations & (PNG_COMPOSE | PNG_RGB_TO_GRAY)) != 0)
+ {
+ png_build_8bit_table(png_ptr, &png_ptr->gamma_to_1,
+ png_reciprocal(png_ptr->colorspace.gamma));
+
+ png_build_8bit_table(png_ptr, &png_ptr->gamma_from_1,
+ png_ptr->screen_gamma > 0 ? png_reciprocal(png_ptr->screen_gamma) :
+ png_ptr->colorspace.gamma/* Probably doing rgb_to_gray */);
+ }
+#endif /* READ_BACKGROUND || READ_ALPHA_MODE || RGB_TO_GRAY */
+ }
+#ifdef PNG_16BIT_SUPPORTED
+ else
+ {
+ png_byte shift, sig_bit;
+
+ if ((png_ptr->color_type & PNG_COLOR_MASK_COLOR) != 0)
+ {
+ sig_bit = png_ptr->sig_bit.red;
+
+ if (png_ptr->sig_bit.green > sig_bit)
+ sig_bit = png_ptr->sig_bit.green;
+
+ if (png_ptr->sig_bit.blue > sig_bit)
+ sig_bit = png_ptr->sig_bit.blue;
+ }
+ else
+ sig_bit = png_ptr->sig_bit.gray;
+
+ /* 16-bit gamma code uses this equation:
+ *
+ * ov = table[(iv & 0xff) >> gamma_shift][iv >> 8]
+ *
+ * Where 'iv' is the input color value and 'ov' is the output value -
+ * pow(iv, gamma).
+ *
+ * Thus the gamma table consists of up to 256 256-entry tables. The table
+ * is selected by the (8-gamma_shift) most significant of the low 8 bits of
+ * the color value then indexed by the upper 8 bits:
+ *
+ * table[low bits][high 8 bits]
+ *
+ * So the table 'n' corresponds to all those 'iv' of:
+ *
+ * <all high 8-bit values><n << gamma_shift>..<(n+1 << gamma_shift)-1>
+ *
+ */
+ if (sig_bit > 0 && sig_bit < 16U)
+ /* shift == insignificant bits */
+ shift = (png_byte)((16U - sig_bit) & 0xff);
+
+ else
+ shift = 0; /* keep all 16 bits */
+
+ if ((png_ptr->transformations & (PNG_16_TO_8 | PNG_SCALE_16_TO_8)) != 0)
+ {
+ /* PNG_MAX_GAMMA_8 is the number of bits to keep - effectively
+ * the significant bits in the *input* when the output will
+ * eventually be 8 bits. By default it is 11.
+ */
+ if (shift < (16U - PNG_MAX_GAMMA_8))
+ shift = (16U - PNG_MAX_GAMMA_8);
+ }
+
+ if (shift > 8U)
+ shift = 8U; /* Guarantees at least one table! */
+
+ png_ptr->gamma_shift = shift;
+
+ /* NOTE: prior to 1.5.4 this test used to include PNG_BACKGROUND (now
+ * PNG_COMPOSE). This effectively smashed the background calculation for
+ * 16-bit output because the 8-bit table assumes the result will be reduced
+ * to 8 bits.
+ */
+ if ((png_ptr->transformations & (PNG_16_TO_8 | PNG_SCALE_16_TO_8)) != 0)
+ png_build_16to8_table(png_ptr, &png_ptr->gamma_16_table, shift,
+ png_ptr->screen_gamma > 0 ? png_product2(png_ptr->colorspace.gamma,
+ png_ptr->screen_gamma) : PNG_FP_1);
+
+ else
+ png_build_16bit_table(png_ptr, &png_ptr->gamma_16_table, shift,
+ png_ptr->screen_gamma > 0 ? png_reciprocal2(png_ptr->colorspace.gamma,
+ png_ptr->screen_gamma) : PNG_FP_1);
+
+#if defined(PNG_READ_BACKGROUND_SUPPORTED) || \
+ defined(PNG_READ_ALPHA_MODE_SUPPORTED) || \
+ defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)
+ if ((png_ptr->transformations & (PNG_COMPOSE | PNG_RGB_TO_GRAY)) != 0)
+ {
+ png_build_16bit_table(png_ptr, &png_ptr->gamma_16_to_1, shift,
+ png_reciprocal(png_ptr->colorspace.gamma));
+
+ /* Notice that the '16 from 1' table should be full precision, however
+ * the lookup on this table still uses gamma_shift, so it can't be.
+ * TODO: fix this.
+ */
+ png_build_16bit_table(png_ptr, &png_ptr->gamma_16_from_1, shift,
+ png_ptr->screen_gamma > 0 ? png_reciprocal(png_ptr->screen_gamma) :
+ png_ptr->colorspace.gamma/* Probably doing rgb_to_gray */);
+ }
+#endif /* READ_BACKGROUND || READ_ALPHA_MODE || RGB_TO_GRAY */
+ }
+#endif /* 16BIT */
+}
+#endif /* READ_GAMMA */
+
+/* HARDWARE OR SOFTWARE OPTION SUPPORT */
+#ifdef PNG_SET_OPTION_SUPPORTED
+int PNGAPI
+png_set_option(png_structrp png_ptr, int option, int onoff)
+{
+ if (png_ptr != NULL && option >= 0 && option < PNG_OPTION_NEXT &&
+ (option & 1) == 0)
+ {
+ int mask = 3 << option;
+ int setting = (2 + (onoff != 0)) << option;
+ int current = png_ptr->options;
+
+ png_ptr->options = (png_byte)(((current & ~mask) | setting) & 0xff);
+
+ return (current & mask) >> option;
+ }
+
+ return PNG_OPTION_INVALID;
+}
+#endif
+
+/* sRGB support */
+#if defined(PNG_SIMPLIFIED_READ_SUPPORTED) ||\
+ defined(PNG_SIMPLIFIED_WRITE_SUPPORTED)
+/* sRGB conversion tables; these are machine generated with the code in
+ * contrib/tools/makesRGB.c. The actual sRGB transfer curve defined in the
+ * specification (see the article at http://en.wikipedia.org/wiki/SRGB)
+ * is used, not the gamma=1/2.2 approximation use elsewhere in libpng.
+ * The sRGB to linear table is exact (to the nearest 16 bit linear fraction).
+ * The inverse (linear to sRGB) table has accuracies as follows:
+ *
+ * For all possible (255*65535+1) input values:
+ *
+ * error: -0.515566 - 0.625971, 79441 (0.475369%) of readings inexact
+ *
+ * For the input values corresponding to the 65536 16-bit values:
+ *
+ * error: -0.513727 - 0.607759, 308 (0.469978%) of readings inexact
+ *
+ * In all cases the inexact readings are only off by one.
+ */
+
+#ifdef PNG_SIMPLIFIED_READ_SUPPORTED
+/* The convert-to-sRGB table is only currently required for read. */
+const png_uint_16 png_sRGB_table[256] =
+{
+ 0,20,40,60,80,99,119,139,
+ 159,179,199,219,241,264,288,313,
+ 340,367,396,427,458,491,526,562,
+ 599,637,677,718,761,805,851,898,
+ 947,997,1048,1101,1156,1212,1270,1330,
+ 1391,1453,1517,1583,1651,1720,1790,1863,
+ 1937,2013,2090,2170,2250,2333,2418,2504,
+ 2592,2681,2773,2866,2961,3058,3157,3258,
+ 3360,3464,3570,3678,3788,3900,4014,4129,
+ 4247,4366,4488,4611,4736,4864,4993,5124,
+ 5257,5392,5530,5669,5810,5953,6099,6246,
+ 6395,6547,6700,6856,7014,7174,7335,7500,
+ 7666,7834,8004,8177,8352,8528,8708,8889,
+ 9072,9258,9445,9635,9828,10022,10219,10417,
+ 10619,10822,11028,11235,11446,11658,11873,12090,
+ 12309,12530,12754,12980,13209,13440,13673,13909,
+ 14146,14387,14629,14874,15122,15371,15623,15878,
+ 16135,16394,16656,16920,17187,17456,17727,18001,
+ 18277,18556,18837,19121,19407,19696,19987,20281,
+ 20577,20876,21177,21481,21787,22096,22407,22721,
+ 23038,23357,23678,24002,24329,24658,24990,25325,
+ 25662,26001,26344,26688,27036,27386,27739,28094,
+ 28452,28813,29176,29542,29911,30282,30656,31033,
+ 31412,31794,32179,32567,32957,33350,33745,34143,
+ 34544,34948,35355,35764,36176,36591,37008,37429,
+ 37852,38278,38706,39138,39572,40009,40449,40891,
+ 41337,41785,42236,42690,43147,43606,44069,44534,
+ 45002,45473,45947,46423,46903,47385,47871,48359,
+ 48850,49344,49841,50341,50844,51349,51858,52369,
+ 52884,53401,53921,54445,54971,55500,56032,56567,
+ 57105,57646,58190,58737,59287,59840,60396,60955,
+ 61517,62082,62650,63221,63795,64372,64952,65535
+};
+#endif /* SIMPLIFIED_READ */
+
+/* The base/delta tables are required for both read and write (but currently
+ * only the simplified versions.)
+ */
+const png_uint_16 png_sRGB_base[512] =
+{
+ 128,1782,3383,4644,5675,6564,7357,8074,
+ 8732,9346,9921,10463,10977,11466,11935,12384,
+ 12816,13233,13634,14024,14402,14769,15125,15473,
+ 15812,16142,16466,16781,17090,17393,17690,17981,
+ 18266,18546,18822,19093,19359,19621,19879,20133,
+ 20383,20630,20873,21113,21349,21583,21813,22041,
+ 22265,22487,22707,22923,23138,23350,23559,23767,
+ 23972,24175,24376,24575,24772,24967,25160,25352,
+ 25542,25730,25916,26101,26284,26465,26645,26823,
+ 27000,27176,27350,27523,27695,27865,28034,28201,
+ 28368,28533,28697,28860,29021,29182,29341,29500,
+ 29657,29813,29969,30123,30276,30429,30580,30730,
+ 30880,31028,31176,31323,31469,31614,31758,31902,
+ 32045,32186,32327,32468,32607,32746,32884,33021,
+ 33158,33294,33429,33564,33697,33831,33963,34095,
+ 34226,34357,34486,34616,34744,34873,35000,35127,
+ 35253,35379,35504,35629,35753,35876,35999,36122,
+ 36244,36365,36486,36606,36726,36845,36964,37083,
+ 37201,37318,37435,37551,37668,37783,37898,38013,
+ 38127,38241,38354,38467,38580,38692,38803,38915,
+ 39026,39136,39246,39356,39465,39574,39682,39790,
+ 39898,40005,40112,40219,40325,40431,40537,40642,
+ 40747,40851,40955,41059,41163,41266,41369,41471,
+ 41573,41675,41777,41878,41979,42079,42179,42279,
+ 42379,42478,42577,42676,42775,42873,42971,43068,
+ 43165,43262,43359,43456,43552,43648,43743,43839,
+ 43934,44028,44123,44217,44311,44405,44499,44592,
+ 44685,44778,44870,44962,45054,45146,45238,45329,
+ 45420,45511,45601,45692,45782,45872,45961,46051,
+ 46140,46229,46318,46406,46494,46583,46670,46758,
+ 46846,46933,47020,47107,47193,47280,47366,47452,
+ 47538,47623,47709,47794,47879,47964,48048,48133,
+ 48217,48301,48385,48468,48552,48635,48718,48801,
+ 48884,48966,49048,49131,49213,49294,49376,49458,
+ 49539,49620,49701,49782,49862,49943,50023,50103,
+ 50183,50263,50342,50422,50501,50580,50659,50738,
+ 50816,50895,50973,51051,51129,51207,51285,51362,
+ 51439,51517,51594,51671,51747,51824,51900,51977,
+ 52053,52129,52205,52280,52356,52432,52507,52582,
+ 52657,52732,52807,52881,52956,53030,53104,53178,
+ 53252,53326,53400,53473,53546,53620,53693,53766,
+ 53839,53911,53984,54056,54129,54201,54273,54345,
+ 54417,54489,54560,54632,54703,54774,54845,54916,
+ 54987,55058,55129,55199,55269,55340,55410,55480,
+ 55550,55620,55689,55759,55828,55898,55967,56036,
+ 56105,56174,56243,56311,56380,56448,56517,56585,
+ 56653,56721,56789,56857,56924,56992,57059,57127,
+ 57194,57261,57328,57395,57462,57529,57595,57662,
+ 57728,57795,57861,57927,57993,58059,58125,58191,
+ 58256,58322,58387,58453,58518,58583,58648,58713,
+ 58778,58843,58908,58972,59037,59101,59165,59230,
+ 59294,59358,59422,59486,59549,59613,59677,59740,
+ 59804,59867,59930,59993,60056,60119,60182,60245,
+ 60308,60370,60433,60495,60558,60620,60682,60744,
+ 60806,60868,60930,60992,61054,61115,61177,61238,
+ 61300,61361,61422,61483,61544,61605,61666,61727,
+ 61788,61848,61909,61969,62030,62090,62150,62211,
+ 62271,62331,62391,62450,62510,62570,62630,62689,
+ 62749,62808,62867,62927,62986,63045,63104,63163,
+ 63222,63281,63340,63398,63457,63515,63574,63632,
+ 63691,63749,63807,63865,63923,63981,64039,64097,
+ 64155,64212,64270,64328,64385,64443,64500,64557,
+ 64614,64672,64729,64786,64843,64900,64956,65013,
+ 65070,65126,65183,65239,65296,65352,65409,65465
+};
+
+const png_byte png_sRGB_delta[512] =
+{
+ 207,201,158,129,113,100,90,82,77,72,68,64,61,59,56,54,
+ 52,50,49,47,46,45,43,42,41,40,39,39,38,37,36,36,
+ 35,34,34,33,33,32,32,31,31,30,30,30,29,29,28,28,
+ 28,27,27,27,27,26,26,26,25,25,25,25,24,24,24,24,
+ 23,23,23,23,23,22,22,22,22,22,22,21,21,21,21,21,
+ 21,20,20,20,20,20,20,20,20,19,19,19,19,19,19,19,
+ 19,18,18,18,18,18,18,18,18,18,18,17,17,17,17,17,
+ 17,17,17,17,17,17,16,16,16,16,16,16,16,16,16,16,
+ 16,16,16,16,15,15,15,15,15,15,15,15,15,15,15,15,
+ 15,15,15,15,14,14,14,14,14,14,14,14,14,14,14,14,
+ 14,14,14,14,14,14,14,13,13,13,13,13,13,13,13,13,
+ 13,13,13,13,13,13,13,13,13,13,13,13,13,13,12,12,
+ 12,12,12,12,12,12,12,12,12,12,12,12,12,12,12,12,
+ 12,12,12,12,12,12,12,12,12,12,12,12,11,11,11,11,
+ 11,11,11,11,11,11,11,11,11,11,11,11,11,11,11,11,
+ 11,11,11,11,11,11,11,11,11,11,11,11,11,11,11,11,
+ 11,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,
+ 10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,
+ 10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,
+ 10,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,
+ 9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,
+ 9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,
+ 9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,
+ 9,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
+ 8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
+ 8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
+ 8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
+ 8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
+ 8,8,8,8,8,8,8,8,8,7,7,7,7,7,7,7,
+ 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
+ 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
+ 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7
+};
+#endif /* SIMPLIFIED READ/WRITE sRGB support */
+
+/* SIMPLIFIED READ/WRITE SUPPORT */
+#if defined(PNG_SIMPLIFIED_READ_SUPPORTED) ||\
+ defined(PNG_SIMPLIFIED_WRITE_SUPPORTED)
+static int
+png_image_free_function(png_voidp argument)
+{
+ png_imagep image = png_voidcast(png_imagep, argument);
+ png_controlp cp = image->opaque;
+ png_control c;
+
+ /* Double check that we have a png_ptr - it should be impossible to get here
+ * without one.
+ */
+ if (cp->png_ptr == NULL)
+ return 0;
+
+ /* First free any data held in the control structure. */
+# ifdef PNG_STDIO_SUPPORTED
+ if (cp->owned_file != 0)
+ {
+ FILE *fp = png_voidcast(FILE*, cp->png_ptr->io_ptr);
+ cp->owned_file = 0;
+
+ /* Ignore errors here. */
+ if (fp != NULL)
+ {
+ cp->png_ptr->io_ptr = NULL;
+ (void)fclose(fp);
+ }
+ }
+# endif
+
+ /* Copy the control structure so that the original, allocated, version can be
+ * safely freed. Notice that a png_error here stops the remainder of the
+ * cleanup, but this is probably fine because that would indicate bad memory
+ * problems anyway.
+ */
+ c = *cp;
+ image->opaque = &c;
+ png_free(c.png_ptr, cp);
+
+ /* Then the structures, calling the correct API. */
+ if (c.for_write != 0)
+ {
+# ifdef PNG_SIMPLIFIED_WRITE_SUPPORTED
+ png_destroy_write_struct(&c.png_ptr, &c.info_ptr);
+# else
+ png_error(c.png_ptr, "simplified write not supported");
+# endif
+ }
+ else
+ {
+# ifdef PNG_SIMPLIFIED_READ_SUPPORTED
+ png_destroy_read_struct(&c.png_ptr, &c.info_ptr, NULL);
+# else
+ png_error(c.png_ptr, "simplified read not supported");
+# endif
+ }
+
+ /* Success. */
+ return 1;
+}
+
+void PNGAPI
+png_image_free(png_imagep image)
+{
+ /* Safely call the real function, but only if doing so is safe at this point
+ * (if not inside an error handling context). Otherwise assume
+ * png_safe_execute will call this API after the return.
+ */
+ if (image != NULL && image->opaque != NULL &&
+ image->opaque->error_buf == NULL)
+ {
+ /* Ignore errors here: */
+ (void)png_safe_execute(image, png_image_free_function, image);
+ image->opaque = NULL;
+ }
+}
+
+int /* PRIVATE */
+png_image_error(png_imagep image, png_const_charp error_message)
+{
+ /* Utility to log an error. */
+ png_safecat(image->message, (sizeof image->message), 0, error_message);
+ image->warning_or_error |= PNG_IMAGE_ERROR;
+ png_image_free(image);
+ return 0;
+}
+
+#endif /* SIMPLIFIED READ/WRITE */
+#endif /* READ || WRITE */
--- /dev/null
+
+/* png.h - header file for PNG reference library
+ *
+ * libpng version 1.6.17, March 26, 2015
+ *
+ * Copyright (c) 1998-2015 Glenn Randers-Pehrson
+ * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
+ * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
+ *
+ * This code is released under the libpng license (See LICENSE, below)
+ *
+ * Authors and maintainers:
+ * libpng versions 0.71, May 1995, through 0.88, January 1996: Guy Schalnat
+ * libpng versions 0.89c, June 1996, through 0.96, May 1997: Andreas Dilger
+ * libpng versions 0.97, January 1998, through 1.6.17, March 26, 2015: Glenn
+ * See also "Contributing Authors", below.
+ *
+ * Note about libpng version numbers:
+ *
+ * Due to various miscommunications, unforeseen code incompatibilities
+ * and occasional factors outside the authors' control, version numbering
+ * on the library has not always been consistent and straightforward.
+ * The following table summarizes matters since version 0.89c, which was
+ * the first widely used release:
+ *
+ * source png.h png.h shared-lib
+ * version string int version
+ * ------- ------ ----- ----------
+ * 0.89c "1.0 beta 3" 0.89 89 1.0.89
+ * 0.90 "1.0 beta 4" 0.90 90 0.90 [should have been 2.0.90]
+ * 0.95 "1.0 beta 5" 0.95 95 0.95 [should have been 2.0.95]
+ * 0.96 "1.0 beta 6" 0.96 96 0.96 [should have been 2.0.96]
+ * 0.97b "1.00.97 beta 7" 1.00.97 97 1.0.1 [should have been 2.0.97]
+ * 0.97c 0.97 97 2.0.97
+ * 0.98 0.98 98 2.0.98
+ * 0.99 0.99 98 2.0.99
+ * 0.99a-m 0.99 99 2.0.99
+ * 1.00 1.00 100 2.1.0 [100 should be 10000]
+ * 1.0.0 (from here on, the 100 2.1.0 [100 should be 10000]
+ * 1.0.1 png.h string is 10001 2.1.0
+ * 1.0.1a-e identical to the 10002 from here on, the shared library
+ * 1.0.2 source version) 10002 is 2.V where V is the source code
+ * 1.0.2a-b 10003 version, except as noted.
+ * 1.0.3 10003
+ * 1.0.3a-d 10004
+ * 1.0.4 10004
+ * 1.0.4a-f 10005
+ * 1.0.5 (+ 2 patches) 10005
+ * 1.0.5a-d 10006
+ * 1.0.5e-r 10100 (not source compatible)
+ * 1.0.5s-v 10006 (not binary compatible)
+ * 1.0.6 (+ 3 patches) 10006 (still binary incompatible)
+ * 1.0.6d-f 10007 (still binary incompatible)
+ * 1.0.6g 10007
+ * 1.0.6h 10007 10.6h (testing xy.z so-numbering)
+ * 1.0.6i 10007 10.6i
+ * 1.0.6j 10007 2.1.0.6j (incompatible with 1.0.0)
+ * 1.0.7beta11-14 DLLNUM 10007 2.1.0.7beta11-14 (binary compatible)
+ * 1.0.7beta15-18 1 10007 2.1.0.7beta15-18 (binary compatible)
+ * 1.0.7rc1-2 1 10007 2.1.0.7rc1-2 (binary compatible)
+ * 1.0.7 1 10007 (still compatible)
+ * 1.0.8beta1-4 1 10008 2.1.0.8beta1-4
+ * 1.0.8rc1 1 10008 2.1.0.8rc1
+ * 1.0.8 1 10008 2.1.0.8
+ * 1.0.9beta1-6 1 10009 2.1.0.9beta1-6
+ * 1.0.9rc1 1 10009 2.1.0.9rc1
+ * 1.0.9beta7-10 1 10009 2.1.0.9beta7-10
+ * 1.0.9rc2 1 10009 2.1.0.9rc2
+ * 1.0.9 1 10009 2.1.0.9
+ * 1.0.10beta1 1 10010 2.1.0.10beta1
+ * 1.0.10rc1 1 10010 2.1.0.10rc1
+ * 1.0.10 1 10010 2.1.0.10
+ * 1.0.11beta1-3 1 10011 2.1.0.11beta1-3
+ * 1.0.11rc1 1 10011 2.1.0.11rc1
+ * 1.0.11 1 10011 2.1.0.11
+ * 1.0.12beta1-2 2 10012 2.1.0.12beta1-2
+ * 1.0.12rc1 2 10012 2.1.0.12rc1
+ * 1.0.12 2 10012 2.1.0.12
+ * 1.1.0a-f - 10100 2.1.1.0a-f (branch abandoned)
+ * 1.2.0beta1-2 2 10200 2.1.2.0beta1-2
+ * 1.2.0beta3-5 3 10200 3.1.2.0beta3-5
+ * 1.2.0rc1 3 10200 3.1.2.0rc1
+ * 1.2.0 3 10200 3.1.2.0
+ * 1.2.1beta1-4 3 10201 3.1.2.1beta1-4
+ * 1.2.1rc1-2 3 10201 3.1.2.1rc1-2
+ * 1.2.1 3 10201 3.1.2.1
+ * 1.2.2beta1-6 12 10202 12.so.0.1.2.2beta1-6
+ * 1.0.13beta1 10 10013 10.so.0.1.0.13beta1
+ * 1.0.13rc1 10 10013 10.so.0.1.0.13rc1
+ * 1.2.2rc1 12 10202 12.so.0.1.2.2rc1
+ * 1.0.13 10 10013 10.so.0.1.0.13
+ * 1.2.2 12 10202 12.so.0.1.2.2
+ * 1.2.3rc1-6 12 10203 12.so.0.1.2.3rc1-6
+ * 1.2.3 12 10203 12.so.0.1.2.3
+ * 1.2.4beta1-3 13 10204 12.so.0.1.2.4beta1-3
+ * 1.0.14rc1 13 10014 10.so.0.1.0.14rc1
+ * 1.2.4rc1 13 10204 12.so.0.1.2.4rc1
+ * 1.0.14 10 10014 10.so.0.1.0.14
+ * 1.2.4 13 10204 12.so.0.1.2.4
+ * 1.2.5beta1-2 13 10205 12.so.0.1.2.5beta1-2
+ * 1.0.15rc1-3 10 10015 10.so.0.1.0.15rc1-3
+ * 1.2.5rc1-3 13 10205 12.so.0.1.2.5rc1-3
+ * 1.0.15 10 10015 10.so.0.1.0.15
+ * 1.2.5 13 10205 12.so.0.1.2.5
+ * 1.2.6beta1-4 13 10206 12.so.0.1.2.6beta1-4
+ * 1.0.16 10 10016 10.so.0.1.0.16
+ * 1.2.6 13 10206 12.so.0.1.2.6
+ * 1.2.7beta1-2 13 10207 12.so.0.1.2.7beta1-2
+ * 1.0.17rc1 10 10017 12.so.0.1.0.17rc1
+ * 1.2.7rc1 13 10207 12.so.0.1.2.7rc1
+ * 1.0.17 10 10017 12.so.0.1.0.17
+ * 1.2.7 13 10207 12.so.0.1.2.7
+ * 1.2.8beta1-5 13 10208 12.so.0.1.2.8beta1-5
+ * 1.0.18rc1-5 10 10018 12.so.0.1.0.18rc1-5
+ * 1.2.8rc1-5 13 10208 12.so.0.1.2.8rc1-5
+ * 1.0.18 10 10018 12.so.0.1.0.18
+ * 1.2.8 13 10208 12.so.0.1.2.8
+ * 1.2.9beta1-3 13 10209 12.so.0.1.2.9beta1-3
+ * 1.2.9beta4-11 13 10209 12.so.0.9[.0]
+ * 1.2.9rc1 13 10209 12.so.0.9[.0]
+ * 1.2.9 13 10209 12.so.0.9[.0]
+ * 1.2.10beta1-7 13 10210 12.so.0.10[.0]
+ * 1.2.10rc1-2 13 10210 12.so.0.10[.0]
+ * 1.2.10 13 10210 12.so.0.10[.0]
+ * 1.4.0beta1-5 14 10400 14.so.0.0[.0]
+ * 1.2.11beta1-4 13 10211 12.so.0.11[.0]
+ * 1.4.0beta7-8 14 10400 14.so.0.0[.0]
+ * 1.2.11 13 10211 12.so.0.11[.0]
+ * 1.2.12 13 10212 12.so.0.12[.0]
+ * 1.4.0beta9-14 14 10400 14.so.0.0[.0]
+ * 1.2.13 13 10213 12.so.0.13[.0]
+ * 1.4.0beta15-36 14 10400 14.so.0.0[.0]
+ * 1.4.0beta37-87 14 10400 14.so.14.0[.0]
+ * 1.4.0rc01 14 10400 14.so.14.0[.0]
+ * 1.4.0beta88-109 14 10400 14.so.14.0[.0]
+ * 1.4.0rc02-08 14 10400 14.so.14.0[.0]
+ * 1.4.0 14 10400 14.so.14.0[.0]
+ * 1.4.1beta01-03 14 10401 14.so.14.1[.0]
+ * 1.4.1rc01 14 10401 14.so.14.1[.0]
+ * 1.4.1beta04-12 14 10401 14.so.14.1[.0]
+ * 1.4.1 14 10401 14.so.14.1[.0]
+ * 1.4.2 14 10402 14.so.14.2[.0]
+ * 1.4.3 14 10403 14.so.14.3[.0]
+ * 1.4.4 14 10404 14.so.14.4[.0]
+ * 1.5.0beta01-58 15 10500 15.so.15.0[.0]
+ * 1.5.0rc01-07 15 10500 15.so.15.0[.0]
+ * 1.5.0 15 10500 15.so.15.0[.0]
+ * 1.5.1beta01-11 15 10501 15.so.15.1[.0]
+ * 1.5.1rc01-02 15 10501 15.so.15.1[.0]
+ * 1.5.1 15 10501 15.so.15.1[.0]
+ * 1.5.2beta01-03 15 10502 15.so.15.2[.0]
+ * 1.5.2rc01-03 15 10502 15.so.15.2[.0]
+ * 1.5.2 15 10502 15.so.15.2[.0]
+ * 1.5.3beta01-10 15 10503 15.so.15.3[.0]
+ * 1.5.3rc01-02 15 10503 15.so.15.3[.0]
+ * 1.5.3beta11 15 10503 15.so.15.3[.0]
+ * 1.5.3 [omitted]
+ * 1.5.4beta01-08 15 10504 15.so.15.4[.0]
+ * 1.5.4rc01 15 10504 15.so.15.4[.0]
+ * 1.5.4 15 10504 15.so.15.4[.0]
+ * 1.5.5beta01-08 15 10505 15.so.15.5[.0]
+ * 1.5.5rc01 15 10505 15.so.15.5[.0]
+ * 1.5.5 15 10505 15.so.15.5[.0]
+ * 1.5.6beta01-07 15 10506 15.so.15.6[.0]
+ * 1.5.6rc01-03 15 10506 15.so.15.6[.0]
+ * 1.5.6 15 10506 15.so.15.6[.0]
+ * 1.5.7beta01-05 15 10507 15.so.15.7[.0]
+ * 1.5.7rc01-03 15 10507 15.so.15.7[.0]
+ * 1.5.7 15 10507 15.so.15.7[.0]
+ * 1.6.0beta01-40 16 10600 16.so.16.0[.0]
+ * 1.6.0rc01-08 16 10600 16.so.16.0[.0]
+ * 1.6.0 16 10600 16.so.16.0[.0]
+ * 1.6.1beta01-09 16 10601 16.so.16.1[.0]
+ * 1.6.1rc01 16 10601 16.so.16.1[.0]
+ * 1.6.1 16 10601 16.so.16.1[.0]
+ * 1.6.2beta01 16 10602 16.so.16.2[.0]
+ * 1.6.2rc01-06 16 10602 16.so.16.2[.0]
+ * 1.6.2 16 10602 16.so.16.2[.0]
+ * 1.6.3beta01-11 16 10603 16.so.16.3[.0]
+ * 1.6.3rc01 16 10603 16.so.16.3[.0]
+ * 1.6.3 16 10603 16.so.16.3[.0]
+ * 1.6.4beta01-02 16 10604 16.so.16.4[.0]
+ * 1.6.4rc01 16 10604 16.so.16.4[.0]
+ * 1.6.4 16 10604 16.so.16.4[.0]
+ * 1.6.5 16 10605 16.so.16.5[.0]
+ * 1.6.6 16 10606 16.so.16.6[.0]
+ * 1.6.7beta01-04 16 10607 16.so.16.7[.0]
+ * 1.6.7rc01-03 16 10607 16.so.16.7[.0]
+ * 1.6.7 16 10607 16.so.16.7[.0]
+ * 1.6.8beta01-02 16 10608 16.so.16.8[.0]
+ * 1.6.8rc01-02 16 10608 16.so.16.8[.0]
+ * 1.6.8 16 10608 16.so.16.8[.0]
+ * 1.6.9beta01-04 16 10609 16.so.16.9[.0]
+ * 1.6.9rc01-02 16 10609 16.so.16.9[.0]
+ * 1.6.9 16 10609 16.so.16.9[.0]
+ * 1.6.10beta01-03 16 10610 16.so.16.10[.0]
+ * 1.6.10rc01-03 16 10610 16.so.16.10[.0]
+ * 1.6.10 16 10610 16.so.16.10[.0]
+ * 1.6.11beta01-06 16 10611 16.so.16.11[.0]
+ * 1.6.11rc01-02 16 10611 16.so.16.11[.0]
+ * 1.6.11 16 10611 16.so.16.11[.0]
+ * 1.6.12rc01-03 16 10612 16.so.16.12[.0]
+ * 1.6.12 16 10612 16.so.16.12[.0]
+ * 1.6.13beta01-04 16 10613 16.so.16.13[.0]
+ * 1.6.13rc01-02 16 10613 16.so.16.13[.0]
+ * 1.6.13 16 10613 16.so.16.13[.0]
+ * 1.6.14beta01-07 16 10614 16.so.16.14[.0]
+ * 1.6.14rc01-02 16 10614 16.so.16.14[.0]
+ * 1.6.14 16 10614 16.so.16.14[.0]
+ * 1.6.15beta01-08 16 10615 16.so.16.15[.0]
+ * 1.6.15rc01-03 16 10615 16.so.16.15[.0]
+ * 1.6.15 16 10615 16.so.16.15[.0]
+ * 1.6.16beta01-03 16 10616 16.so.16.16[.0]
+ * 1.6.16rc01-02 16 10616 16.so.16.16[.0]
+ * 1.6.16 16 10616 16.so.16.16[.0]
+ * 1.6.17beta01-06 16 10617 16.so.16.17[.0]
+ * 1.6.17rc01-06 16 10617 16.so.16.17[.0]
+ * 1.6.17 16 10617 16.so.16.17[.0]
+ *
+ * Henceforth the source version will match the shared-library major
+ * and minor numbers; the shared-library major version number will be
+ * used for changes in backward compatibility, as it is intended. The
+ * PNG_LIBPNG_VER macro, which is not used within libpng but is available
+ * for applications, is an unsigned integer of the form xyyzz corresponding
+ * to the source version x.y.z (leading zeros in y and z). Beta versions
+ * were given the previous public release number plus a letter, until
+ * version 1.0.6j; from then on they were given the upcoming public
+ * release number plus "betaNN" or "rcNN".
+ *
+ * Binary incompatibility exists only when applications make direct access
+ * to the info_ptr or png_ptr members through png.h, and the compiled
+ * application is loaded with a different version of the library.
+ *
+ * DLLNUM will change each time there are forward or backward changes
+ * in binary compatibility (e.g., when a new feature is added).
+ *
+ * See libpng-manual.txt or libpng.3 for more information. The PNG
+ * specification is available as a W3C Recommendation and as an ISO
+ * Specification, <http://www.w3.org/TR/2003/REC-PNG-20031110/
+ */
+
+/*
+ * COPYRIGHT NOTICE, DISCLAIMER, and LICENSE:
+ *
+ * If you modify libpng you may insert additional notices immediately following
+ * this sentence.
+ *
+ * This code is released under the libpng license.
+ *
+ * libpng versions 1.2.6, August 15, 2004, through 1.6.17, March 26, 2015, are
+ * Copyright (c) 2004, 2006-2015 Glenn Randers-Pehrson, and are
+ * distributed according to the same disclaimer and license as libpng-1.2.5
+ * with the following individual added to the list of Contributing Authors:
+ *
+ * Cosmin Truta
+ *
+ * libpng versions 1.0.7, July 1, 2000, through 1.2.5, October 3, 2002, are
+ * Copyright (c) 2000-2002 Glenn Randers-Pehrson, and are
+ * distributed according to the same disclaimer and license as libpng-1.0.6
+ * with the following individuals added to the list of Contributing Authors:
+ *
+ * Simon-Pierre Cadieux
+ * Eric S. Raymond
+ * Gilles Vollant
+ *
+ * and with the following additions to the disclaimer:
+ *
+ * There is no warranty against interference with your enjoyment of the
+ * library or against infringement. There is no warranty that our
+ * efforts or the library will fulfill any of your particular purposes
+ * or needs. This library is provided with all faults, and the entire
+ * risk of satisfactory quality, performance, accuracy, and effort is with
+ * the user.
+ *
+ * libpng versions 0.97, January 1998, through 1.0.6, March 20, 2000, are
+ * Copyright (c) 1998, 1999, 2000 Glenn Randers-Pehrson, and are
+ * distributed according to the same disclaimer and license as libpng-0.96,
+ * with the following individuals added to the list of Contributing Authors:
+ *
+ * Tom Lane
+ * Glenn Randers-Pehrson
+ * Willem van Schaik
+ *
+ * libpng versions 0.89, June 1996, through 0.96, May 1997, are
+ * Copyright (c) 1996, 1997 Andreas Dilger
+ * Distributed according to the same disclaimer and license as libpng-0.88,
+ * with the following individuals added to the list of Contributing Authors:
+ *
+ * John Bowler
+ * Kevin Bracey
+ * Sam Bushell
+ * Magnus Holmgren
+ * Greg Roelofs
+ * Tom Tanner
+ *
+ * libpng versions 0.5, May 1995, through 0.88, January 1996, are
+ * Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
+ *
+ * For the purposes of this copyright and license, "Contributing Authors"
+ * is defined as the following set of individuals:
+ *
+ * Andreas Dilger
+ * Dave Martindale
+ * Guy Eric Schalnat
+ * Paul Schmidt
+ * Tim Wegner
+ *
+ * The PNG Reference Library is supplied "AS IS". The Contributing Authors
+ * and Group 42, Inc. disclaim all warranties, expressed or implied,
+ * including, without limitation, the warranties of merchantability and of
+ * fitness for any purpose. The Contributing Authors and Group 42, Inc.
+ * assume no liability for direct, indirect, incidental, special, exemplary,
+ * or consequential damages, which may result from the use of the PNG
+ * Reference Library, even if advised of the possibility of such damage.
+ *
+ * Permission is hereby granted to use, copy, modify, and distribute this
+ * source code, or portions hereof, for any purpose, without fee, subject
+ * to the following restrictions:
+ *
+ * 1. The origin of this source code must not be misrepresented.
+ *
+ * 2. Altered versions must be plainly marked as such and must not
+ * be misrepresented as being the original source.
+ *
+ * 3. This Copyright notice may not be removed or altered from
+ * any source or altered source distribution.
+ *
+ * The Contributing Authors and Group 42, Inc. specifically permit, without
+ * fee, and encourage the use of this source code as a component to
+ * supporting the PNG file format in commercial products. If you use this
+ * source code in a product, acknowledgment is not required but would be
+ * appreciated.
+ */
+
+/*
+ * A "png_get_copyright" function is available, for convenient use in "about"
+ * boxes and the like:
+ *
+ * printf("%s", png_get_copyright(NULL));
+ *
+ * Also, the PNG logo (in PNG format, of course) is supplied in the
+ * files "pngbar.png" and "pngbar.jpg (88x31) and "pngnow.png" (98x31).
+ */
+
+/*
+ * Libpng is OSI Certified Open Source Software. OSI Certified is a
+ * certification mark of the Open Source Initiative.
+ */
+
+/*
+ * The contributing authors would like to thank all those who helped
+ * with testing, bug fixes, and patience. This wouldn't have been
+ * possible without all of you.
+ *
+ * Thanks to Frank J. T. Wojcik for helping with the documentation.
+ */
+
+/*
+ * Y2K compliance in libpng:
+ * =========================
+ *
+ * March 26, 2015
+ *
+ * Since the PNG Development group is an ad-hoc body, we can't make
+ * an official declaration.
+ *
+ * This is your unofficial assurance that libpng from version 0.71 and
+ * upward through 1.6.17 are Y2K compliant. It is my belief that
+ * earlier versions were also Y2K compliant.
+ *
+ * Libpng only has two year fields. One is a 2-byte unsigned integer
+ * that will hold years up to 65535. The other, which is deprecated,
+ * holds the date in text format, and will hold years up to 9999.
+ *
+ * The integer is
+ * "png_uint_16 year" in png_time_struct.
+ *
+ * The string is
+ * "char time_buffer[29]" in png_struct. This is no longer used
+ * in libpng-1.6.x and will be removed from libpng-1.7.0.
+ *
+ * There are seven time-related functions:
+ * png.c: png_convert_to_rfc_1123_buffer() in png.c
+ * (formerly png_convert_to_rfc_1123() prior to libpng-1.5.x and
+ * png_convert_to_rfc_1152() in error prior to libpng-0.98)
+ * png_convert_from_struct_tm() in pngwrite.c, called in pngwrite.c
+ * png_convert_from_time_t() in pngwrite.c
+ * png_get_tIME() in pngget.c
+ * png_handle_tIME() in pngrutil.c, called in pngread.c
+ * png_set_tIME() in pngset.c
+ * png_write_tIME() in pngwutil.c, called in pngwrite.c
+ *
+ * All handle dates properly in a Y2K environment. The
+ * png_convert_from_time_t() function calls gmtime() to convert from system
+ * clock time, which returns (year - 1900), which we properly convert to
+ * the full 4-digit year. There is a possibility that libpng applications
+ * are not passing 4-digit years into the png_convert_to_rfc_1123_buffer()
+ * function, or that they are incorrectly passing only a 2-digit year
+ * instead of "year - 1900" into the png_convert_from_struct_tm() function,
+ * but this is not under our control. The libpng documentation has always
+ * stated that it works with 4-digit years, and the APIs have been
+ * documented as such.
+ *
+ * The tIME chunk itself is also Y2K compliant. It uses a 2-byte unsigned
+ * integer to hold the year, and can hold years as large as 65535.
+ *
+ * zlib, upon which libpng depends, is also Y2K compliant. It contains
+ * no date-related code.
+ *
+ * Glenn Randers-Pehrson
+ * libpng maintainer
+ * PNG Development Group
+ */
+
+#ifndef PNG_H
+#define PNG_H
+
+/* This is not the place to learn how to use libpng. The file libpng-manual.txt
+ * describes how to use libpng, and the file example.c summarizes it
+ * with some code on which to build. This file is useful for looking
+ * at the actual function definitions and structure components. If that
+ * file has been stripped from your copy of libpng, you can find it at
+ * <http://www.libpng.org/pub/png/libpng-manual.txt>
+ *
+ * If you just need to read a PNG file and don't want to read the documentation
+ * skip to the end of this file and read the section entitled 'simplified API'.
+ */
+
+/* Version information for png.h - this should match the version in png.c */
+#define PNG_LIBPNG_VER_STRING "1.6.17"
+#define PNG_HEADER_VERSION_STRING \
+ " libpng version 1.6.17 - March 26, 2015\n"
+
+#define PNG_LIBPNG_VER_SONUM 16
+#define PNG_LIBPNG_VER_DLLNUM 16
+
+/* These should match the first 3 components of PNG_LIBPNG_VER_STRING: */
+#define PNG_LIBPNG_VER_MAJOR 1
+#define PNG_LIBPNG_VER_MINOR 6
+#define PNG_LIBPNG_VER_RELEASE 17
+
+/* This should match the numeric part of the final component of
+ * PNG_LIBPNG_VER_STRING, omitting any leading zero:
+ */
+
+#define PNG_LIBPNG_VER_BUILD 0
+
+/* Release Status */
+#define PNG_LIBPNG_BUILD_ALPHA 1
+#define PNG_LIBPNG_BUILD_BETA 2
+#define PNG_LIBPNG_BUILD_RC 3
+#define PNG_LIBPNG_BUILD_STABLE 4
+#define PNG_LIBPNG_BUILD_RELEASE_STATUS_MASK 7
+
+/* Release-Specific Flags */
+#define PNG_LIBPNG_BUILD_PATCH 8 /* Can be OR'ed with
+ PNG_LIBPNG_BUILD_STABLE only */
+#define PNG_LIBPNG_BUILD_PRIVATE 16 /* Cannot be OR'ed with
+ PNG_LIBPNG_BUILD_SPECIAL */
+#define PNG_LIBPNG_BUILD_SPECIAL 32 /* Cannot be OR'ed with
+ PNG_LIBPNG_BUILD_PRIVATE */
+
+#define PNG_LIBPNG_BUILD_BASE_TYPE PNG_LIBPNG_BUILD_STABLE
+
+/* Careful here. At one time, Guy wanted to use 082, but that would be octal.
+ * We must not include leading zeros.
+ * Versions 0.7 through 1.0.0 were in the range 0 to 100 here (only
+ * version 1.0.0 was mis-numbered 100 instead of 10000). From
+ * version 1.0.1 it's xxyyzz, where x=major, y=minor, z=release
+ */
+#define PNG_LIBPNG_VER 10617 /* 1.6.17 */
+
+/* Library configuration: these options cannot be changed after
+ * the library has been built.
+ */
+#ifndef PNGLCONF_H
+ /* If pnglibconf.h is missing, you can
+ * copy scripts/pnglibconf.h.prebuilt to pnglibconf.h
+ */
+# include "pnglibconf.h"
+#endif
+
+#ifndef PNG_VERSION_INFO_ONLY
+ /* Machine specific configuration. */
+# include "pngconf.h"
+#endif
+
+/*
+ * Added at libpng-1.2.8
+ *
+ * Ref MSDN: Private as priority over Special
+ * VS_FF_PRIVATEBUILD File *was not* built using standard release
+ * procedures. If this value is given, the StringFileInfo block must
+ * contain a PrivateBuild string.
+ *
+ * VS_FF_SPECIALBUILD File *was* built by the original company using
+ * standard release procedures but is a variation of the standard
+ * file of the same version number. If this value is given, the
+ * StringFileInfo block must contain a SpecialBuild string.
+ */
+
+#ifdef PNG_USER_PRIVATEBUILD /* From pnglibconf.h */
+# define PNG_LIBPNG_BUILD_TYPE \
+ (PNG_LIBPNG_BUILD_BASE_TYPE | PNG_LIBPNG_BUILD_PRIVATE)
+#else
+# ifdef PNG_LIBPNG_SPECIALBUILD
+# define PNG_LIBPNG_BUILD_TYPE \
+ (PNG_LIBPNG_BUILD_BASE_TYPE | PNG_LIBPNG_BUILD_SPECIAL)
+# else
+# define PNG_LIBPNG_BUILD_TYPE (PNG_LIBPNG_BUILD_BASE_TYPE)
+# endif
+#endif
+
+#ifndef PNG_VERSION_INFO_ONLY
+
+/* Inhibit C++ name-mangling for libpng functions but not for system calls. */
+#ifdef __cplusplus
+extern "C" {
+#endif /* __cplusplus */
+
+/* Version information for C files, stored in png.c. This had better match
+ * the version above.
+ */
+#define png_libpng_ver png_get_header_ver(NULL)
+
+/* This file is arranged in several sections:
+ *
+ * 1. Any configuration options that can be specified by for the application
+ * code when it is built. (Build time configuration is in pnglibconf.h)
+ * 2. Type definitions (base types are defined in pngconf.h), structure
+ * definitions.
+ * 3. Exported library functions.
+ * 4. Simplified API.
+ *
+ * The library source code has additional files (principally pngpriv.h) that
+ * allow configuration of the library.
+ */
+/* Section 1: run time configuration
+ * See pnglibconf.h for build time configuration
+ *
+ * Run time configuration allows the application to choose between
+ * implementations of certain arithmetic APIs. The default is set
+ * at build time and recorded in pnglibconf.h, but it is safe to
+ * override these (and only these) settings. Note that this won't
+ * change what the library does, only application code, and the
+ * settings can (and probably should) be made on a per-file basis
+ * by setting the #defines before including png.h
+ *
+ * Use macros to read integers from PNG data or use the exported
+ * functions?
+ * PNG_USE_READ_MACROS: use the macros (see below) Note that
+ * the macros evaluate their argument multiple times.
+ * PNG_NO_USE_READ_MACROS: call the relevant library function.
+ *
+ * Use the alternative algorithm for compositing alpha samples that
+ * does not use division?
+ * PNG_READ_COMPOSITE_NODIV_SUPPORTED: use the 'no division'
+ * algorithm.
+ * PNG_NO_READ_COMPOSITE_NODIV: use the 'division' algorithm.
+ *
+ * How to handle benign errors if PNG_ALLOW_BENIGN_ERRORS is
+ * false?
+ * PNG_ALLOW_BENIGN_ERRORS: map calls to the benign error
+ * APIs to png_warning.
+ * Otherwise the calls are mapped to png_error.
+ */
+
+/* Section 2: type definitions, including structures and compile time
+ * constants.
+ * See pngconf.h for base types that vary by machine/system
+ */
+
+/* This triggers a compiler error in png.c, if png.c and png.h
+ * do not agree upon the version number.
+ */
+typedef char* png_libpng_version_1_6_17;
+
+/* Basic control structions. Read libpng-manual.txt or libpng.3 for more info.
+ *
+ * png_struct is the cache of information used while reading or writing a single
+ * PNG file. One of these is always required, although the simplified API
+ * (below) hides the creation and destruction of it.
+ */
+typedef struct png_struct_def png_struct;
+typedef const png_struct * png_const_structp;
+typedef png_struct * png_structp;
+typedef png_struct * * png_structpp;
+
+/* png_info contains information read from or to be written to a PNG file. One
+ * or more of these must exist while reading or creating a PNG file. The
+ * information is not used by libpng during read but is used to control what
+ * gets written when a PNG file is created. "png_get_" function calls read
+ * information during read and "png_set_" functions calls write information
+ * when creating a PNG.
+ * been moved into a separate header file that is not accessible to
+ * applications. Read libpng-manual.txt or libpng.3 for more info.
+ */
+typedef struct png_info_def png_info;
+typedef png_info * png_infop;
+typedef const png_info * png_const_infop;
+typedef png_info * * png_infopp;
+
+/* Types with names ending 'p' are pointer types. The corresponding types with
+ * names ending 'rp' are identical pointer types except that the pointer is
+ * marked 'restrict', which means that it is the only pointer to the object
+ * passed to the function. Applications should not use the 'restrict' types;
+ * it is always valid to pass 'p' to a pointer with a function argument of the
+ * corresponding 'rp' type. Different compilers have different rules with
+ * regard to type matching in the presence of 'restrict'. For backward
+ * compatibility libpng callbacks never have 'restrict' in their parameters and,
+ * consequentially, writing portable application code is extremely difficult if
+ * an attempt is made to use 'restrict'.
+ */
+typedef png_struct * PNG_RESTRICT png_structrp;
+typedef const png_struct * PNG_RESTRICT png_const_structrp;
+typedef png_info * PNG_RESTRICT png_inforp;
+typedef const png_info * PNG_RESTRICT png_const_inforp;
+
+/* Three color definitions. The order of the red, green, and blue, (and the
+ * exact size) is not important, although the size of the fields need to
+ * be png_byte or png_uint_16 (as defined below).
+ */
+typedef struct png_color_struct
+{
+ png_byte red;
+ png_byte green;
+ png_byte blue;
+} png_color;
+typedef png_color * png_colorp;
+typedef const png_color * png_const_colorp;
+typedef png_color * * png_colorpp;
+
+typedef struct png_color_16_struct
+{
+ png_byte index; /* used for palette files */
+ png_uint_16 red; /* for use in red green blue files */
+ png_uint_16 green;
+ png_uint_16 blue;
+ png_uint_16 gray; /* for use in grayscale files */
+} png_color_16;
+typedef png_color_16 * png_color_16p;
+typedef const png_color_16 * png_const_color_16p;
+typedef png_color_16 * * png_color_16pp;
+
+typedef struct png_color_8_struct
+{
+ png_byte red; /* for use in red green blue files */
+ png_byte green;
+ png_byte blue;
+ png_byte gray; /* for use in grayscale files */
+ png_byte alpha; /* for alpha channel files */
+} png_color_8;
+typedef png_color_8 * png_color_8p;
+typedef const png_color_8 * png_const_color_8p;
+typedef png_color_8 * * png_color_8pp;
+
+/*
+ * The following two structures are used for the in-core representation
+ * of sPLT chunks.
+ */
+typedef struct png_sPLT_entry_struct
+{
+ png_uint_16 red;
+ png_uint_16 green;
+ png_uint_16 blue;
+ png_uint_16 alpha;
+ png_uint_16 frequency;
+} png_sPLT_entry;
+typedef png_sPLT_entry * png_sPLT_entryp;
+typedef const png_sPLT_entry * png_const_sPLT_entryp;
+typedef png_sPLT_entry * * png_sPLT_entrypp;
+
+/* When the depth of the sPLT palette is 8 bits, the color and alpha samples
+ * occupy the LSB of their respective members, and the MSB of each member
+ * is zero-filled. The frequency member always occupies the full 16 bits.
+ */
+
+typedef struct png_sPLT_struct
+{
+ png_charp name; /* palette name */
+ png_byte depth; /* depth of palette samples */
+ png_sPLT_entryp entries; /* palette entries */
+ png_int_32 nentries; /* number of palette entries */
+} png_sPLT_t;
+typedef png_sPLT_t * png_sPLT_tp;
+typedef const png_sPLT_t * png_const_sPLT_tp;
+typedef png_sPLT_t * * png_sPLT_tpp;
+
+#ifdef PNG_TEXT_SUPPORTED
+/* png_text holds the contents of a text/ztxt/itxt chunk in a PNG file,
+ * and whether that contents is compressed or not. The "key" field
+ * points to a regular zero-terminated C string. The "text" fields can be a
+ * regular C string, an empty string, or a NULL pointer.
+ * However, the structure returned by png_get_text() will always contain
+ * the "text" field as a regular zero-terminated C string (possibly
+ * empty), never a NULL pointer, so it can be safely used in printf() and
+ * other string-handling functions. Note that the "itxt_length", "lang", and
+ * "lang_key" members of the structure only exist when the library is built
+ * with iTXt chunk support. Prior to libpng-1.4.0 the library was built by
+ * default without iTXt support. Also note that when iTXt *is* supported,
+ * the "lang" and "lang_key" fields contain NULL pointers when the
+ * "compression" field contains * PNG_TEXT_COMPRESSION_NONE or
+ * PNG_TEXT_COMPRESSION_zTXt. Note that the "compression value" is not the
+ * same as what appears in the PNG tEXt/zTXt/iTXt chunk's "compression flag"
+ * which is always 0 or 1, or its "compression method" which is always 0.
+ */
+typedef struct png_text_struct
+{
+ int compression; /* compression value:
+ -1: tEXt, none
+ 0: zTXt, deflate
+ 1: iTXt, none
+ 2: iTXt, deflate */
+ png_charp key; /* keyword, 1-79 character description of "text" */
+ png_charp text; /* comment, may be an empty string (ie "")
+ or a NULL pointer */
+ png_size_t text_length; /* length of the text string */
+ png_size_t itxt_length; /* length of the itxt string */
+ png_charp lang; /* language code, 0-79 characters
+ or a NULL pointer */
+ png_charp lang_key; /* keyword translated UTF-8 string, 0 or more
+ chars or a NULL pointer */
+} png_text;
+typedef png_text * png_textp;
+typedef const png_text * png_const_textp;
+typedef png_text * * png_textpp;
+#endif
+
+/* Supported compression types for text in PNG files (tEXt, and zTXt).
+ * The values of the PNG_TEXT_COMPRESSION_ defines should NOT be changed. */
+#define PNG_TEXT_COMPRESSION_NONE_WR -3
+#define PNG_TEXT_COMPRESSION_zTXt_WR -2
+#define PNG_TEXT_COMPRESSION_NONE -1
+#define PNG_TEXT_COMPRESSION_zTXt 0
+#define PNG_ITXT_COMPRESSION_NONE 1
+#define PNG_ITXT_COMPRESSION_zTXt 2
+#define PNG_TEXT_COMPRESSION_LAST 3 /* Not a valid value */
+
+/* png_time is a way to hold the time in an machine independent way.
+ * Two conversions are provided, both from time_t and struct tm. There
+ * is no portable way to convert to either of these structures, as far
+ * as I know. If you know of a portable way, send it to me. As a side
+ * note - PNG has always been Year 2000 compliant!
+ */
+typedef struct png_time_struct
+{
+ png_uint_16 year; /* full year, as in, 1995 */
+ png_byte month; /* month of year, 1 - 12 */
+ png_byte day; /* day of month, 1 - 31 */
+ png_byte hour; /* hour of day, 0 - 23 */
+ png_byte minute; /* minute of hour, 0 - 59 */
+ png_byte second; /* second of minute, 0 - 60 (for leap seconds) */
+} png_time;
+typedef png_time * png_timep;
+typedef const png_time * png_const_timep;
+typedef png_time * * png_timepp;
+
+#if defined(PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED) ||\
+ defined(PNG_USER_CHUNKS_SUPPORTED)
+/* png_unknown_chunk is a structure to hold queued chunks for which there is
+ * no specific support. The idea is that we can use this to queue
+ * up private chunks for output even though the library doesn't actually
+ * know about their semantics.
+ *
+ * The data in the structure is set by libpng on read and used on write.
+ */
+typedef struct png_unknown_chunk_t
+{
+ png_byte name[5]; /* Textual chunk name with '\0' terminator */
+ png_byte *data; /* Data, should not be modified on read! */
+ png_size_t size;
+
+ /* On write 'location' must be set using the flag values listed below.
+ * Notice that on read it is set by libpng however the values stored have
+ * more bits set than are listed below. Always treat the value as a
+ * bitmask. On write set only one bit - setting multiple bits may cause the
+ * chunk to be written in multiple places.
+ */
+ png_byte location; /* mode of operation at read time */
+}
+png_unknown_chunk;
+
+typedef png_unknown_chunk * png_unknown_chunkp;
+typedef const png_unknown_chunk * png_const_unknown_chunkp;
+typedef png_unknown_chunk * * png_unknown_chunkpp;
+#endif
+
+/* Flag values for the unknown chunk location byte. */
+#define PNG_HAVE_IHDR 0x01
+#define PNG_HAVE_PLTE 0x02
+#define PNG_AFTER_IDAT 0x08
+
+/* Maximum positive integer used in PNG is (2^31)-1 */
+#define PNG_UINT_31_MAX ((png_uint_32)0x7fffffffL)
+#define PNG_UINT_32_MAX ((png_uint_32)(-1))
+#define PNG_SIZE_MAX ((png_size_t)(-1))
+
+/* These are constants for fixed point values encoded in the
+ * PNG specification manner (x100000)
+ */
+#define PNG_FP_1 100000
+#define PNG_FP_HALF 50000
+#define PNG_FP_MAX ((png_fixed_point)0x7fffffffL)
+#define PNG_FP_MIN (-PNG_FP_MAX)
+
+/* These describe the color_type field in png_info. */
+/* color type masks */
+#define PNG_COLOR_MASK_PALETTE 1
+#define PNG_COLOR_MASK_COLOR 2
+#define PNG_COLOR_MASK_ALPHA 4
+
+/* color types. Note that not all combinations are legal */
+#define PNG_COLOR_TYPE_GRAY 0
+#define PNG_COLOR_TYPE_PALETTE (PNG_COLOR_MASK_COLOR | PNG_COLOR_MASK_PALETTE)
+#define PNG_COLOR_TYPE_RGB (PNG_COLOR_MASK_COLOR)
+#define PNG_COLOR_TYPE_RGB_ALPHA (PNG_COLOR_MASK_COLOR | PNG_COLOR_MASK_ALPHA)
+#define PNG_COLOR_TYPE_GRAY_ALPHA (PNG_COLOR_MASK_ALPHA)
+/* aliases */
+#define PNG_COLOR_TYPE_RGBA PNG_COLOR_TYPE_RGB_ALPHA
+#define PNG_COLOR_TYPE_GA PNG_COLOR_TYPE_GRAY_ALPHA
+
+/* This is for compression type. PNG 1.0-1.2 only define the single type. */
+#define PNG_COMPRESSION_TYPE_BASE 0 /* Deflate method 8, 32K window */
+#define PNG_COMPRESSION_TYPE_DEFAULT PNG_COMPRESSION_TYPE_BASE
+
+/* This is for filter type. PNG 1.0-1.2 only define the single type. */
+#define PNG_FILTER_TYPE_BASE 0 /* Single row per-byte filtering */
+#define PNG_INTRAPIXEL_DIFFERENCING 64 /* Used only in MNG datastreams */
+#define PNG_FILTER_TYPE_DEFAULT PNG_FILTER_TYPE_BASE
+
+/* These are for the interlacing type. These values should NOT be changed. */
+#define PNG_INTERLACE_NONE 0 /* Non-interlaced image */
+#define PNG_INTERLACE_ADAM7 1 /* Adam7 interlacing */
+#define PNG_INTERLACE_LAST 2 /* Not a valid value */
+
+/* These are for the oFFs chunk. These values should NOT be changed. */
+#define PNG_OFFSET_PIXEL 0 /* Offset in pixels */
+#define PNG_OFFSET_MICROMETER 1 /* Offset in micrometers (1/10^6 meter) */
+#define PNG_OFFSET_LAST 2 /* Not a valid value */
+
+/* These are for the pCAL chunk. These values should NOT be changed. */
+#define PNG_EQUATION_LINEAR 0 /* Linear transformation */
+#define PNG_EQUATION_BASE_E 1 /* Exponential base e transform */
+#define PNG_EQUATION_ARBITRARY 2 /* Arbitrary base exponential transform */
+#define PNG_EQUATION_HYPERBOLIC 3 /* Hyperbolic sine transformation */
+#define PNG_EQUATION_LAST 4 /* Not a valid value */
+
+/* These are for the sCAL chunk. These values should NOT be changed. */
+#define PNG_SCALE_UNKNOWN 0 /* unknown unit (image scale) */
+#define PNG_SCALE_METER 1 /* meters per pixel */
+#define PNG_SCALE_RADIAN 2 /* radians per pixel */
+#define PNG_SCALE_LAST 3 /* Not a valid value */
+
+/* These are for the pHYs chunk. These values should NOT be changed. */
+#define PNG_RESOLUTION_UNKNOWN 0 /* pixels/unknown unit (aspect ratio) */
+#define PNG_RESOLUTION_METER 1 /* pixels/meter */
+#define PNG_RESOLUTION_LAST 2 /* Not a valid value */
+
+/* These are for the sRGB chunk. These values should NOT be changed. */
+#define PNG_sRGB_INTENT_PERCEPTUAL 0
+#define PNG_sRGB_INTENT_RELATIVE 1
+#define PNG_sRGB_INTENT_SATURATION 2
+#define PNG_sRGB_INTENT_ABSOLUTE 3
+#define PNG_sRGB_INTENT_LAST 4 /* Not a valid value */
+
+/* This is for text chunks */
+#define PNG_KEYWORD_MAX_LENGTH 79
+
+/* Maximum number of entries in PLTE/sPLT/tRNS arrays */
+#define PNG_MAX_PALETTE_LENGTH 256
+
+/* These determine if an ancillary chunk's data has been successfully read
+ * from the PNG header, or if the application has filled in the corresponding
+ * data in the info_struct to be written into the output file. The values
+ * of the PNG_INFO_<chunk> defines should NOT be changed.
+ */
+#define PNG_INFO_gAMA 0x0001
+#define PNG_INFO_sBIT 0x0002
+#define PNG_INFO_cHRM 0x0004
+#define PNG_INFO_PLTE 0x0008
+#define PNG_INFO_tRNS 0x0010
+#define PNG_INFO_bKGD 0x0020
+#define PNG_INFO_hIST 0x0040
+#define PNG_INFO_pHYs 0x0080
+#define PNG_INFO_oFFs 0x0100
+#define PNG_INFO_tIME 0x0200
+#define PNG_INFO_pCAL 0x0400
+#define PNG_INFO_sRGB 0x0800 /* GR-P, 0.96a */
+#define PNG_INFO_iCCP 0x1000 /* ESR, 1.0.6 */
+#define PNG_INFO_sPLT 0x2000 /* ESR, 1.0.6 */
+#define PNG_INFO_sCAL 0x4000 /* ESR, 1.0.6 */
+#define PNG_INFO_IDAT 0x8000 /* ESR, 1.0.6 */
+
+/* This is used for the transformation routines, as some of them
+ * change these values for the row. It also should enable using
+ * the routines for other purposes.
+ */
+typedef struct png_row_info_struct
+{
+ png_uint_32 width; /* width of row */
+ png_size_t rowbytes; /* number of bytes in row */
+ png_byte color_type; /* color type of row */
+ png_byte bit_depth; /* bit depth of row */
+ png_byte channels; /* number of channels (1, 2, 3, or 4) */
+ png_byte pixel_depth; /* bits per pixel (depth * channels) */
+} png_row_info;
+
+typedef png_row_info * png_row_infop;
+typedef png_row_info * * png_row_infopp;
+
+/* These are the function types for the I/O functions and for the functions
+ * that allow the user to override the default I/O functions with his or her
+ * own. The png_error_ptr type should match that of user-supplied warning
+ * and error functions, while the png_rw_ptr type should match that of the
+ * user read/write data functions. Note that the 'write' function must not
+ * modify the buffer it is passed. The 'read' function, on the other hand, is
+ * expected to return the read data in the buffer.
+ */
+typedef PNG_CALLBACK(void, *png_error_ptr, (png_structp, png_const_charp));
+typedef PNG_CALLBACK(void, *png_rw_ptr, (png_structp, png_bytep, png_size_t));
+typedef PNG_CALLBACK(void, *png_flush_ptr, (png_structp));
+typedef PNG_CALLBACK(void, *png_read_status_ptr, (png_structp, png_uint_32,
+ int));
+typedef PNG_CALLBACK(void, *png_write_status_ptr, (png_structp, png_uint_32,
+ int));
+
+#ifdef PNG_PROGRESSIVE_READ_SUPPORTED
+typedef PNG_CALLBACK(void, *png_progressive_info_ptr, (png_structp, png_infop));
+typedef PNG_CALLBACK(void, *png_progressive_end_ptr, (png_structp, png_infop));
+
+/* The following callback receives png_uint_32 row_number, int pass for the
+ * png_bytep data of the row. When transforming an interlaced image the
+ * row number is the row number within the sub-image of the interlace pass, so
+ * the value will increase to the height of the sub-image (not the full image)
+ * then reset to 0 for the next pass.
+ *
+ * Use PNG_ROW_FROM_PASS_ROW(row, pass) and PNG_COL_FROM_PASS_COL(col, pass) to
+ * find the output pixel (x,y) given an interlaced sub-image pixel
+ * (row,col,pass). (See below for these macros.)
+ */
+typedef PNG_CALLBACK(void, *png_progressive_row_ptr, (png_structp, png_bytep,
+ png_uint_32, int));
+#endif
+
+#if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) || \
+ defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED)
+typedef PNG_CALLBACK(void, *png_user_transform_ptr, (png_structp, png_row_infop,
+ png_bytep));
+#endif
+
+#ifdef PNG_USER_CHUNKS_SUPPORTED
+typedef PNG_CALLBACK(int, *png_user_chunk_ptr, (png_structp,
+ png_unknown_chunkp));
+#endif
+#ifdef PNG_UNKNOWN_CHUNKS_SUPPORTED
+/* not used anywhere */
+/* typedef PNG_CALLBACK(void, *png_unknown_chunk_ptr, (png_structp)); */
+#endif
+
+#ifdef PNG_SETJMP_SUPPORTED
+/* This must match the function definition in <setjmp.h>, and the application
+ * must include this before png.h to obtain the definition of jmp_buf. The
+ * function is required to be PNG_NORETURN, but this is not checked. If the
+ * function does return the application will crash via an abort() or similar
+ * system level call.
+ *
+ * If you get a warning here while building the library you may need to make
+ * changes to ensure that pnglibconf.h records the calling convention used by
+ * your compiler. This may be very difficult - try using a different compiler
+ * to build the library!
+ */
+PNG_FUNCTION(void, (PNGCAPI *png_longjmp_ptr), PNGARG((jmp_buf, int)), typedef);
+#endif
+
+/* Transform masks for the high-level interface */
+#define PNG_TRANSFORM_IDENTITY 0x0000 /* read and write */
+#define PNG_TRANSFORM_STRIP_16 0x0001 /* read only */
+#define PNG_TRANSFORM_STRIP_ALPHA 0x0002 /* read only */
+#define PNG_TRANSFORM_PACKING 0x0004 /* read and write */
+#define PNG_TRANSFORM_PACKSWAP 0x0008 /* read and write */
+#define PNG_TRANSFORM_EXPAND 0x0010 /* read only */
+#define PNG_TRANSFORM_INVERT_MONO 0x0020 /* read and write */
+#define PNG_TRANSFORM_SHIFT 0x0040 /* read and write */
+#define PNG_TRANSFORM_BGR 0x0080 /* read and write */
+#define PNG_TRANSFORM_SWAP_ALPHA 0x0100 /* read and write */
+#define PNG_TRANSFORM_SWAP_ENDIAN 0x0200 /* read and write */
+#define PNG_TRANSFORM_INVERT_ALPHA 0x0400 /* read and write */
+#define PNG_TRANSFORM_STRIP_FILLER 0x0800 /* write only */
+/* Added to libpng-1.2.34 */
+#define PNG_TRANSFORM_STRIP_FILLER_BEFORE PNG_TRANSFORM_STRIP_FILLER
+#define PNG_TRANSFORM_STRIP_FILLER_AFTER 0x1000 /* write only */
+/* Added to libpng-1.4.0 */
+#define PNG_TRANSFORM_GRAY_TO_RGB 0x2000 /* read only */
+/* Added to libpng-1.5.4 */
+#define PNG_TRANSFORM_EXPAND_16 0x4000 /* read only */
+#define PNG_TRANSFORM_SCALE_16 0x8000 /* read only */
+
+/* Flags for MNG supported features */
+#define PNG_FLAG_MNG_EMPTY_PLTE 0x01
+#define PNG_FLAG_MNG_FILTER_64 0x04
+#define PNG_ALL_MNG_FEATURES 0x05
+
+/* NOTE: prior to 1.5 these functions had no 'API' style declaration,
+ * this allowed the zlib default functions to be used on Windows
+ * platforms. In 1.5 the zlib default malloc (which just calls malloc and
+ * ignores the first argument) should be completely compatible with the
+ * following.
+ */
+typedef PNG_CALLBACK(png_voidp, *png_malloc_ptr, (png_structp,
+ png_alloc_size_t));
+typedef PNG_CALLBACK(void, *png_free_ptr, (png_structp, png_voidp));
+
+/* Section 3: exported functions
+ * Here are the function definitions most commonly used. This is not
+ * the place to find out how to use libpng. See libpng-manual.txt for the
+ * full explanation, see example.c for the summary. This just provides
+ * a simple one line description of the use of each function.
+ *
+ * The PNG_EXPORT() and PNG_EXPORTA() macros used below are defined in
+ * pngconf.h and in the *.dfn files in the scripts directory.
+ *
+ * PNG_EXPORT(ordinal, type, name, (args));
+ *
+ * ordinal: ordinal that is used while building
+ * *.def files. The ordinal value is only
+ * relevant when preprocessing png.h with
+ * the *.dfn files for building symbol table
+ * entries, and are removed by pngconf.h.
+ * type: return type of the function
+ * name: function name
+ * args: function arguments, with types
+ *
+ * When we wish to append attributes to a function prototype we use
+ * the PNG_EXPORTA() macro instead.
+ *
+ * PNG_EXPORTA(ordinal, type, name, (args), attributes);
+ *
+ * ordinal, type, name, and args: same as in PNG_EXPORT().
+ * attributes: function attributes
+ */
+
+/* Returns the version number of the library */
+PNG_EXPORT(1, png_uint_32, png_access_version_number, (void));
+
+/* Tell lib we have already handled the first <num_bytes> magic bytes.
+ * Handling more than 8 bytes from the beginning of the file is an error.
+ */
+PNG_EXPORT(2, void, png_set_sig_bytes, (png_structrp png_ptr, int num_bytes));
+
+/* Check sig[start] through sig[start + num_to_check - 1] to see if it's a
+ * PNG file. Returns zero if the supplied bytes match the 8-byte PNG
+ * signature, and non-zero otherwise. Having num_to_check == 0 or
+ * start > 7 will always fail (ie return non-zero).
+ */
+PNG_EXPORT(3, int, png_sig_cmp, (png_const_bytep sig, png_size_t start,
+ png_size_t num_to_check));
+
+/* Simple signature checking function. This is the same as calling
+ * png_check_sig(sig, n) := !png_sig_cmp(sig, 0, n).
+ */
+#define png_check_sig(sig, n) !png_sig_cmp((sig), 0, (n))
+
+/* Allocate and initialize png_ptr struct for reading, and any other memory. */
+PNG_EXPORTA(4, png_structp, png_create_read_struct,
+ (png_const_charp user_png_ver, png_voidp error_ptr,
+ png_error_ptr error_fn, png_error_ptr warn_fn),
+ PNG_ALLOCATED);
+
+/* Allocate and initialize png_ptr struct for writing, and any other memory */
+PNG_EXPORTA(5, png_structp, png_create_write_struct,
+ (png_const_charp user_png_ver, png_voidp error_ptr, png_error_ptr error_fn,
+ png_error_ptr warn_fn),
+ PNG_ALLOCATED);
+
+PNG_EXPORT(6, png_size_t, png_get_compression_buffer_size,
+ (png_const_structrp png_ptr));
+
+PNG_EXPORT(7, void, png_set_compression_buffer_size, (png_structrp png_ptr,
+ png_size_t size));
+
+/* Moved from pngconf.h in 1.4.0 and modified to ensure setjmp/longjmp
+ * match up.
+ */
+#ifdef PNG_SETJMP_SUPPORTED
+/* This function returns the jmp_buf built in to *png_ptr. It must be
+ * supplied with an appropriate 'longjmp' function to use on that jmp_buf
+ * unless the default error function is overridden in which case NULL is
+ * acceptable. The size of the jmp_buf is checked against the actual size
+ * allocated by the library - the call will return NULL on a mismatch
+ * indicating an ABI mismatch.
+ */
+PNG_EXPORT(8, jmp_buf*, png_set_longjmp_fn, (png_structrp png_ptr,
+ png_longjmp_ptr longjmp_fn, size_t jmp_buf_size));
+# define png_jmpbuf(png_ptr) \
+ (*png_set_longjmp_fn((png_ptr), longjmp, (sizeof (jmp_buf))))
+#else
+# define png_jmpbuf(png_ptr) \
+ (LIBPNG_WAS_COMPILED_WITH__PNG_NO_SETJMP)
+#endif
+/* This function should be used by libpng applications in place of
+ * longjmp(png_ptr->jmpbuf, val). If longjmp_fn() has been set, it
+ * will use it; otherwise it will call PNG_ABORT(). This function was
+ * added in libpng-1.5.0.
+ */
+PNG_EXPORTA(9, void, png_longjmp, (png_const_structrp png_ptr, int val),
+ PNG_NORETURN);
+
+#ifdef PNG_READ_SUPPORTED
+/* Reset the compression stream */
+PNG_EXPORTA(10, int, png_reset_zstream, (png_structrp png_ptr), PNG_DEPRECATED);
+#endif
+
+/* New functions added in libpng-1.0.2 (not enabled by default until 1.2.0) */
+#ifdef PNG_USER_MEM_SUPPORTED
+PNG_EXPORTA(11, png_structp, png_create_read_struct_2,
+ (png_const_charp user_png_ver, png_voidp error_ptr, png_error_ptr error_fn,
+ png_error_ptr warn_fn,
+ png_voidp mem_ptr, png_malloc_ptr malloc_fn, png_free_ptr free_fn),
+ PNG_ALLOCATED);
+PNG_EXPORTA(12, png_structp, png_create_write_struct_2,
+ (png_const_charp user_png_ver, png_voidp error_ptr, png_error_ptr error_fn,
+ png_error_ptr warn_fn,
+ png_voidp mem_ptr, png_malloc_ptr malloc_fn, png_free_ptr free_fn),
+ PNG_ALLOCATED);
+#endif
+
+/* Write the PNG file signature. */
+PNG_EXPORT(13, void, png_write_sig, (png_structrp png_ptr));
+
+/* Write a PNG chunk - size, type, (optional) data, CRC. */
+PNG_EXPORT(14, void, png_write_chunk, (png_structrp png_ptr, png_const_bytep
+ chunk_name, png_const_bytep data, png_size_t length));
+
+/* Write the start of a PNG chunk - length and chunk name. */
+PNG_EXPORT(15, void, png_write_chunk_start, (png_structrp png_ptr,
+ png_const_bytep chunk_name, png_uint_32 length));
+
+/* Write the data of a PNG chunk started with png_write_chunk_start(). */
+PNG_EXPORT(16, void, png_write_chunk_data, (png_structrp png_ptr,
+ png_const_bytep data, png_size_t length));
+
+/* Finish a chunk started with png_write_chunk_start() (includes CRC). */
+PNG_EXPORT(17, void, png_write_chunk_end, (png_structrp png_ptr));
+
+/* Allocate and initialize the info structure */
+PNG_EXPORTA(18, png_infop, png_create_info_struct, (png_const_structrp png_ptr),
+ PNG_ALLOCATED);
+
+/* DEPRECATED: this function allowed init structures to be created using the
+ * default allocation method (typically malloc). Use is deprecated in 1.6.0 and
+ * the API will be removed in the future.
+ */
+PNG_EXPORTA(19, void, png_info_init_3, (png_infopp info_ptr,
+ png_size_t png_info_struct_size), PNG_DEPRECATED);
+
+/* Writes all the PNG information before the image. */
+PNG_EXPORT(20, void, png_write_info_before_PLTE,
+ (png_structrp png_ptr, png_const_inforp info_ptr));
+PNG_EXPORT(21, void, png_write_info,
+ (png_structrp png_ptr, png_const_inforp info_ptr));
+
+#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
+/* Read the information before the actual image data. */
+PNG_EXPORT(22, void, png_read_info,
+ (png_structrp png_ptr, png_inforp info_ptr));
+#endif
+
+#ifdef PNG_TIME_RFC1123_SUPPORTED
+ /* Convert to a US string format: there is no localization support in this
+ * routine. The original implementation used a 29 character buffer in
+ * png_struct, this will be removed in future versions.
+ */
+#if PNG_LIBPNG_VER < 10700
+/* To do: remove this from libpng17 (and from libpng17/png.c and pngstruct.h) */
+PNG_EXPORTA(23, png_const_charp, png_convert_to_rfc1123, (png_structrp png_ptr,
+ png_const_timep ptime),PNG_DEPRECATED);
+#endif
+PNG_EXPORT(241, int, png_convert_to_rfc1123_buffer, (char out[29],
+ png_const_timep ptime));
+#endif
+
+#ifdef PNG_CONVERT_tIME_SUPPORTED
+/* Convert from a struct tm to png_time */
+PNG_EXPORT(24, void, png_convert_from_struct_tm, (png_timep ptime,
+ const struct tm * ttime));
+
+/* Convert from time_t to png_time. Uses gmtime() */
+PNG_EXPORT(25, void, png_convert_from_time_t, (png_timep ptime, time_t ttime));
+#endif /* CONVERT_tIME */
+
+#ifdef PNG_READ_EXPAND_SUPPORTED
+/* Expand data to 24-bit RGB, or 8-bit grayscale, with alpha if available. */
+PNG_EXPORT(26, void, png_set_expand, (png_structrp png_ptr));
+PNG_EXPORT(27, void, png_set_expand_gray_1_2_4_to_8, (png_structrp png_ptr));
+PNG_EXPORT(28, void, png_set_palette_to_rgb, (png_structrp png_ptr));
+PNG_EXPORT(29, void, png_set_tRNS_to_alpha, (png_structrp png_ptr));
+#endif
+
+#ifdef PNG_READ_EXPAND_16_SUPPORTED
+/* Expand to 16-bit channels, forces conversion of palette to RGB and expansion
+ * of a tRNS chunk if present.
+ */
+PNG_EXPORT(221, void, png_set_expand_16, (png_structrp png_ptr));
+#endif
+
+#if defined(PNG_READ_BGR_SUPPORTED) || defined(PNG_WRITE_BGR_SUPPORTED)
+/* Use blue, green, red order for pixels. */
+PNG_EXPORT(30, void, png_set_bgr, (png_structrp png_ptr));
+#endif
+
+#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
+/* Expand the grayscale to 24-bit RGB if necessary. */
+PNG_EXPORT(31, void, png_set_gray_to_rgb, (png_structrp png_ptr));
+#endif
+
+#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
+/* Reduce RGB to grayscale. */
+#define PNG_ERROR_ACTION_NONE 1
+#define PNG_ERROR_ACTION_WARN 2
+#define PNG_ERROR_ACTION_ERROR 3
+#define PNG_RGB_TO_GRAY_DEFAULT (-1)/*for red/green coefficients*/
+
+PNG_FP_EXPORT(32, void, png_set_rgb_to_gray, (png_structrp png_ptr,
+ int error_action, double red, double green))
+PNG_FIXED_EXPORT(33, void, png_set_rgb_to_gray_fixed, (png_structrp png_ptr,
+ int error_action, png_fixed_point red, png_fixed_point green))
+
+PNG_EXPORT(34, png_byte, png_get_rgb_to_gray_status, (png_const_structrp
+ png_ptr));
+#endif
+
+#ifdef PNG_BUILD_GRAYSCALE_PALETTE_SUPPORTED
+PNG_EXPORT(35, void, png_build_grayscale_palette, (int bit_depth,
+ png_colorp palette));
+#endif
+
+#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
+/* How the alpha channel is interpreted - this affects how the color channels
+ * of a PNG file are returned to the calling application when an alpha channel,
+ * or a tRNS chunk in a palette file, is present.
+ *
+ * This has no effect on the way pixels are written into a PNG output
+ * datastream. The color samples in a PNG datastream are never premultiplied
+ * with the alpha samples.
+ *
+ * The default is to return data according to the PNG specification: the alpha
+ * channel is a linear measure of the contribution of the pixel to the
+ * corresponding composited pixel, and the color channels are unassociated
+ * (not premultiplied). The gamma encoded color channels must be scaled
+ * according to the contribution and to do this it is necessary to undo
+ * the encoding, scale the color values, perform the composition and reencode
+ * the values. This is the 'PNG' mode.
+ *
+ * The alternative is to 'associate' the alpha with the color information by
+ * storing color channel values that have been scaled by the alpha.
+ * image. These are the 'STANDARD', 'ASSOCIATED' or 'PREMULTIPLIED' modes
+ * (the latter being the two common names for associated alpha color channels).
+ *
+ * For the 'OPTIMIZED' mode, a pixel is treated as opaque only if the alpha
+ * value is equal to the maximum value.
+ *
+ * The final choice is to gamma encode the alpha channel as well. This is
+ * broken because, in practice, no implementation that uses this choice
+ * correctly undoes the encoding before handling alpha composition. Use this
+ * choice only if other serious errors in the software or hardware you use
+ * mandate it; the typical serious error is for dark halos to appear around
+ * opaque areas of the composited PNG image because of arithmetic overflow.
+ *
+ * The API function png_set_alpha_mode specifies which of these choices to use
+ * with an enumerated 'mode' value and the gamma of the required output:
+ */
+#define PNG_ALPHA_PNG 0 /* according to the PNG standard */
+#define PNG_ALPHA_STANDARD 1 /* according to Porter/Duff */
+#define PNG_ALPHA_ASSOCIATED 1 /* as above; this is the normal practice */
+#define PNG_ALPHA_PREMULTIPLIED 1 /* as above */
+#define PNG_ALPHA_OPTIMIZED 2 /* 'PNG' for opaque pixels, else 'STANDARD' */
+#define PNG_ALPHA_BROKEN 3 /* the alpha channel is gamma encoded */
+
+PNG_FP_EXPORT(227, void, png_set_alpha_mode, (png_structrp png_ptr, int mode,
+ double output_gamma))
+PNG_FIXED_EXPORT(228, void, png_set_alpha_mode_fixed, (png_structrp png_ptr,
+ int mode, png_fixed_point output_gamma))
+#endif
+
+#if defined(PNG_GAMMA_SUPPORTED) || defined(PNG_READ_ALPHA_MODE_SUPPORTED)
+/* The output_gamma value is a screen gamma in libpng terminology: it expresses
+ * how to decode the output values, not how they are encoded.
+ */
+#define PNG_DEFAULT_sRGB -1 /* sRGB gamma and color space */
+#define PNG_GAMMA_MAC_18 -2 /* Old Mac '1.8' gamma and color space */
+#define PNG_GAMMA_sRGB 220000 /* Television standards--matches sRGB gamma */
+#define PNG_GAMMA_LINEAR PNG_FP_1 /* Linear */
+#endif
+
+/* The following are examples of calls to png_set_alpha_mode to achieve the
+ * required overall gamma correction and, where necessary, alpha
+ * premultiplication.
+ *
+ * png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_DEFAULT_sRGB);
+ * This is the default libpng handling of the alpha channel - it is not
+ * pre-multiplied into the color components. In addition the call states
+ * that the output is for a sRGB system and causes all PNG files without gAMA
+ * chunks to be assumed to be encoded using sRGB.
+ *
+ * png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_GAMMA_MAC);
+ * In this case the output is assumed to be something like an sRGB conformant
+ * display preceeded by a power-law lookup table of power 1.45. This is how
+ * early Mac systems behaved.
+ *
+ * png_set_alpha_mode(pp, PNG_ALPHA_STANDARD, PNG_GAMMA_LINEAR);
+ * This is the classic Jim Blinn approach and will work in academic
+ * environments where everything is done by the book. It has the shortcoming
+ * of assuming that input PNG data with no gamma information is linear - this
+ * is unlikely to be correct unless the PNG files where generated locally.
+ * Most of the time the output precision will be so low as to show
+ * significant banding in dark areas of the image.
+ *
+ * png_set_expand_16(pp);
+ * png_set_alpha_mode(pp, PNG_ALPHA_STANDARD, PNG_DEFAULT_sRGB);
+ * This is a somewhat more realistic Jim Blinn inspired approach. PNG files
+ * are assumed to have the sRGB encoding if not marked with a gamma value and
+ * the output is always 16 bits per component. This permits accurate scaling
+ * and processing of the data. If you know that your input PNG files were
+ * generated locally you might need to replace PNG_DEFAULT_sRGB with the
+ * correct value for your system.
+ *
+ * png_set_alpha_mode(pp, PNG_ALPHA_OPTIMIZED, PNG_DEFAULT_sRGB);
+ * If you just need to composite the PNG image onto an existing background
+ * and if you control the code that does this you can use the optimization
+ * setting. In this case you just copy completely opaque pixels to the
+ * output. For pixels that are not completely transparent (you just skip
+ * those) you do the composition math using png_composite or png_composite_16
+ * below then encode the resultant 8-bit or 16-bit values to match the output
+ * encoding.
+ *
+ * Other cases
+ * If neither the PNG nor the standard linear encoding work for you because
+ * of the software or hardware you use then you have a big problem. The PNG
+ * case will probably result in halos around the image. The linear encoding
+ * will probably result in a washed out, too bright, image (it's actually too
+ * contrasty.) Try the ALPHA_OPTIMIZED mode above - this will probably
+ * substantially reduce the halos. Alternatively try:
+ *
+ * png_set_alpha_mode(pp, PNG_ALPHA_BROKEN, PNG_DEFAULT_sRGB);
+ * This option will also reduce the halos, but there will be slight dark
+ * halos round the opaque parts of the image where the background is light.
+ * In the OPTIMIZED mode the halos will be light halos where the background
+ * is dark. Take your pick - the halos are unavoidable unless you can get
+ * your hardware/software fixed! (The OPTIMIZED approach is slightly
+ * faster.)
+ *
+ * When the default gamma of PNG files doesn't match the output gamma.
+ * If you have PNG files with no gamma information png_set_alpha_mode allows
+ * you to provide a default gamma, but it also sets the ouput gamma to the
+ * matching value. If you know your PNG files have a gamma that doesn't
+ * match the output you can take advantage of the fact that
+ * png_set_alpha_mode always sets the output gamma but only sets the PNG
+ * default if it is not already set:
+ *
+ * png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_DEFAULT_sRGB);
+ * png_set_alpha_mode(pp, PNG_ALPHA_PNG, PNG_GAMMA_MAC);
+ * The first call sets both the default and the output gamma values, the
+ * second call overrides the output gamma without changing the default. This
+ * is easier than achieving the same effect with png_set_gamma. You must use
+ * PNG_ALPHA_PNG for the first call - internal checking in png_set_alpha will
+ * fire if more than one call to png_set_alpha_mode and png_set_background is
+ * made in the same read operation, however multiple calls with PNG_ALPHA_PNG
+ * are ignored.
+ */
+
+#ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
+PNG_EXPORT(36, void, png_set_strip_alpha, (png_structrp png_ptr));
+#endif
+
+#if defined(PNG_READ_SWAP_ALPHA_SUPPORTED) || \
+ defined(PNG_WRITE_SWAP_ALPHA_SUPPORTED)
+PNG_EXPORT(37, void, png_set_swap_alpha, (png_structrp png_ptr));
+#endif
+
+#if defined(PNG_READ_INVERT_ALPHA_SUPPORTED) || \
+ defined(PNG_WRITE_INVERT_ALPHA_SUPPORTED)
+PNG_EXPORT(38, void, png_set_invert_alpha, (png_structrp png_ptr));
+#endif
+
+#if defined(PNG_READ_FILLER_SUPPORTED) || defined(PNG_WRITE_FILLER_SUPPORTED)
+/* Add a filler byte to 8-bit Gray or 24-bit RGB images. */
+PNG_EXPORT(39, void, png_set_filler, (png_structrp png_ptr, png_uint_32 filler,
+ int flags));
+/* The values of the PNG_FILLER_ defines should NOT be changed */
+# define PNG_FILLER_BEFORE 0
+# define PNG_FILLER_AFTER 1
+/* Add an alpha byte to 8-bit Gray or 24-bit RGB images. */
+PNG_EXPORT(40, void, png_set_add_alpha, (png_structrp png_ptr,
+ png_uint_32 filler, int flags));
+#endif /* READ_FILLER || WRITE_FILLER */
+
+#if defined(PNG_READ_SWAP_SUPPORTED) || defined(PNG_WRITE_SWAP_SUPPORTED)
+/* Swap bytes in 16-bit depth files. */
+PNG_EXPORT(41, void, png_set_swap, (png_structrp png_ptr));
+#endif
+
+#if defined(PNG_READ_PACK_SUPPORTED) || defined(PNG_WRITE_PACK_SUPPORTED)
+/* Use 1 byte per pixel in 1, 2, or 4-bit depth files. */
+PNG_EXPORT(42, void, png_set_packing, (png_structrp png_ptr));
+#endif
+
+#if defined(PNG_READ_PACKSWAP_SUPPORTED) || \
+ defined(PNG_WRITE_PACKSWAP_SUPPORTED)
+/* Swap packing order of pixels in bytes. */
+PNG_EXPORT(43, void, png_set_packswap, (png_structrp png_ptr));
+#endif
+
+#if defined(PNG_READ_SHIFT_SUPPORTED) || defined(PNG_WRITE_SHIFT_SUPPORTED)
+/* Converts files to legal bit depths. */
+PNG_EXPORT(44, void, png_set_shift, (png_structrp png_ptr, png_const_color_8p
+ true_bits));
+#endif
+
+#if defined(PNG_READ_INTERLACING_SUPPORTED) || \
+ defined(PNG_WRITE_INTERLACING_SUPPORTED)
+/* Have the code handle the interlacing. Returns the number of passes.
+ * MUST be called before png_read_update_info or png_start_read_image,
+ * otherwise it will not have the desired effect. Note that it is still
+ * necessary to call png_read_row or png_read_rows png_get_image_height
+ * times for each pass.
+*/
+PNG_EXPORT(45, int, png_set_interlace_handling, (png_structrp png_ptr));
+#endif
+
+#if defined(PNG_READ_INVERT_SUPPORTED) || defined(PNG_WRITE_INVERT_SUPPORTED)
+/* Invert monochrome files */
+PNG_EXPORT(46, void, png_set_invert_mono, (png_structrp png_ptr));
+#endif
+
+#ifdef PNG_READ_BACKGROUND_SUPPORTED
+/* Handle alpha and tRNS by replacing with a background color. Prior to
+ * libpng-1.5.4 this API must not be called before the PNG file header has been
+ * read. Doing so will result in unexpected behavior and possible warnings or
+ * errors if the PNG file contains a bKGD chunk.
+ */
+PNG_FP_EXPORT(47, void, png_set_background, (png_structrp png_ptr,
+ png_const_color_16p background_color, int background_gamma_code,
+ int need_expand, double background_gamma))
+PNG_FIXED_EXPORT(215, void, png_set_background_fixed, (png_structrp png_ptr,
+ png_const_color_16p background_color, int background_gamma_code,
+ int need_expand, png_fixed_point background_gamma))
+#endif
+#ifdef PNG_READ_BACKGROUND_SUPPORTED
+# define PNG_BACKGROUND_GAMMA_UNKNOWN 0
+# define PNG_BACKGROUND_GAMMA_SCREEN 1
+# define PNG_BACKGROUND_GAMMA_FILE 2
+# define PNG_BACKGROUND_GAMMA_UNIQUE 3
+#endif
+
+#ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
+/* Scale a 16-bit depth file down to 8-bit, accurately. */
+PNG_EXPORT(229, void, png_set_scale_16, (png_structrp png_ptr));
+#endif
+
+#ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
+#define PNG_READ_16_TO_8 SUPPORTED /* Name prior to 1.5.4 */
+/* Strip the second byte of information from a 16-bit depth file. */
+PNG_EXPORT(48, void, png_set_strip_16, (png_structrp png_ptr));
+#endif
+
+#ifdef PNG_READ_QUANTIZE_SUPPORTED
+/* Turn on quantizing, and reduce the palette to the number of colors
+ * available.
+ */
+PNG_EXPORT(49, void, png_set_quantize, (png_structrp png_ptr,
+ png_colorp palette, int num_palette, int maximum_colors,
+ png_const_uint_16p histogram, int full_quantize));
+#endif
+
+#ifdef PNG_READ_GAMMA_SUPPORTED
+/* The threshold on gamma processing is configurable but hard-wired into the
+ * library. The following is the floating point variant.
+ */
+#define PNG_GAMMA_THRESHOLD (PNG_GAMMA_THRESHOLD_FIXED*.00001)
+
+/* Handle gamma correction. Screen_gamma=(display_exponent).
+ * NOTE: this API simply sets the screen and file gamma values. It will
+ * therefore override the value for gamma in a PNG file if it is called after
+ * the file header has been read - use with care - call before reading the PNG
+ * file for best results!
+ *
+ * These routines accept the same gamma values as png_set_alpha_mode (described
+ * above). The PNG_GAMMA_ defines and PNG_DEFAULT_sRGB can be passed to either
+ * API (floating point or fixed.) Notice, however, that the 'file_gamma' value
+ * is the inverse of a 'screen gamma' value.
+ */
+PNG_FP_EXPORT(50, void, png_set_gamma, (png_structrp png_ptr,
+ double screen_gamma, double override_file_gamma))
+PNG_FIXED_EXPORT(208, void, png_set_gamma_fixed, (png_structrp png_ptr,
+ png_fixed_point screen_gamma, png_fixed_point override_file_gamma))
+#endif
+
+#ifdef PNG_WRITE_FLUSH_SUPPORTED
+/* Set how many lines between output flushes - 0 for no flushing */
+PNG_EXPORT(51, void, png_set_flush, (png_structrp png_ptr, int nrows));
+/* Flush the current PNG output buffer */
+PNG_EXPORT(52, void, png_write_flush, (png_structrp png_ptr));
+#endif
+
+/* Optional update palette with requested transformations */
+PNG_EXPORT(53, void, png_start_read_image, (png_structrp png_ptr));
+
+/* Optional call to update the users info structure */
+PNG_EXPORT(54, void, png_read_update_info, (png_structrp png_ptr,
+ png_inforp info_ptr));
+
+#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
+/* Read one or more rows of image data. */
+PNG_EXPORT(55, void, png_read_rows, (png_structrp png_ptr, png_bytepp row,
+ png_bytepp display_row, png_uint_32 num_rows));
+#endif
+
+#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
+/* Read a row of data. */
+PNG_EXPORT(56, void, png_read_row, (png_structrp png_ptr, png_bytep row,
+ png_bytep display_row));
+#endif
+
+#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
+/* Read the whole image into memory at once. */
+PNG_EXPORT(57, void, png_read_image, (png_structrp png_ptr, png_bytepp image));
+#endif
+
+/* Write a row of image data */
+PNG_EXPORT(58, void, png_write_row, (png_structrp png_ptr,
+ png_const_bytep row));
+
+/* Write a few rows of image data: (*row) is not written; however, the type
+ * is declared as writeable to maintain compatibility with previous versions
+ * of libpng and to allow the 'display_row' array from read_rows to be passed
+ * unchanged to write_rows.
+ */
+PNG_EXPORT(59, void, png_write_rows, (png_structrp png_ptr, png_bytepp row,
+ png_uint_32 num_rows));
+
+/* Write the image data */
+PNG_EXPORT(60, void, png_write_image, (png_structrp png_ptr, png_bytepp image));
+
+/* Write the end of the PNG file. */
+PNG_EXPORT(61, void, png_write_end, (png_structrp png_ptr,
+ png_inforp info_ptr));
+
+#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
+/* Read the end of the PNG file. */
+PNG_EXPORT(62, void, png_read_end, (png_structrp png_ptr, png_inforp info_ptr));
+#endif
+
+/* Free any memory associated with the png_info_struct */
+PNG_EXPORT(63, void, png_destroy_info_struct, (png_const_structrp png_ptr,
+ png_infopp info_ptr_ptr));
+
+/* Free any memory associated with the png_struct and the png_info_structs */
+PNG_EXPORT(64, void, png_destroy_read_struct, (png_structpp png_ptr_ptr,
+ png_infopp info_ptr_ptr, png_infopp end_info_ptr_ptr));
+
+/* Free any memory associated with the png_struct and the png_info_structs */
+PNG_EXPORT(65, void, png_destroy_write_struct, (png_structpp png_ptr_ptr,
+ png_infopp info_ptr_ptr));
+
+/* Set the libpng method of handling chunk CRC errors */
+PNG_EXPORT(66, void, png_set_crc_action, (png_structrp png_ptr, int crit_action,
+ int ancil_action));
+
+/* Values for png_set_crc_action() say how to handle CRC errors in
+ * ancillary and critical chunks, and whether to use the data contained
+ * therein. Note that it is impossible to "discard" data in a critical
+ * chunk. For versions prior to 0.90, the action was always error/quit,
+ * whereas in version 0.90 and later, the action for CRC errors in ancillary
+ * chunks is warn/discard. These values should NOT be changed.
+ *
+ * value action:critical action:ancillary
+ */
+#define PNG_CRC_DEFAULT 0 /* error/quit warn/discard data */
+#define PNG_CRC_ERROR_QUIT 1 /* error/quit error/quit */
+#define PNG_CRC_WARN_DISCARD 2 /* (INVALID) warn/discard data */
+#define PNG_CRC_WARN_USE 3 /* warn/use data warn/use data */
+#define PNG_CRC_QUIET_USE 4 /* quiet/use data quiet/use data */
+#define PNG_CRC_NO_CHANGE 5 /* use current value use current value */
+
+#ifdef PNG_WRITE_SUPPORTED
+/* These functions give the user control over the scan-line filtering in
+ * libpng and the compression methods used by zlib. These functions are
+ * mainly useful for testing, as the defaults should work with most users.
+ * Those users who are tight on memory or want faster performance at the
+ * expense of compression can modify them. See the compression library
+ * header file (zlib.h) for an explination of the compression functions.
+ */
+
+/* Set the filtering method(s) used by libpng. Currently, the only valid
+ * value for "method" is 0.
+ */
+PNG_EXPORT(67, void, png_set_filter, (png_structrp png_ptr, int method,
+ int filters));
+#endif /* WRITE */
+
+/* Flags for png_set_filter() to say which filters to use. The flags
+ * are chosen so that they don't conflict with real filter types
+ * below, in case they are supplied instead of the #defined constants.
+ * These values should NOT be changed.
+ */
+#define PNG_NO_FILTERS 0x00
+#define PNG_FILTER_NONE 0x08
+#define PNG_FILTER_SUB 0x10
+#define PNG_FILTER_UP 0x20
+#define PNG_FILTER_AVG 0x40
+#define PNG_FILTER_PAETH 0x80
+#define PNG_ALL_FILTERS (PNG_FILTER_NONE | PNG_FILTER_SUB | PNG_FILTER_UP | \
+ PNG_FILTER_AVG | PNG_FILTER_PAETH)
+
+/* Filter values (not flags) - used in pngwrite.c, pngwutil.c for now.
+ * These defines should NOT be changed.
+ */
+#define PNG_FILTER_VALUE_NONE 0
+#define PNG_FILTER_VALUE_SUB 1
+#define PNG_FILTER_VALUE_UP 2
+#define PNG_FILTER_VALUE_AVG 3
+#define PNG_FILTER_VALUE_PAETH 4
+#define PNG_FILTER_VALUE_LAST 5
+
+#ifdef PNG_WRITE_SUPPORTED
+#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED /* EXPERIMENTAL */
+/* The "heuristic_method" is given by one of the PNG_FILTER_HEURISTIC_
+ * defines, either the default (minimum-sum-of-absolute-differences), or
+ * the experimental method (weighted-minimum-sum-of-absolute-differences).
+ *
+ * Weights are factors >= 1.0, indicating how important it is to keep the
+ * filter type consistent between rows. Larger numbers mean the current
+ * filter is that many times as likely to be the same as the "num_weights"
+ * previous filters. This is cumulative for each previous row with a weight.
+ * There needs to be "num_weights" values in "filter_weights", or it can be
+ * NULL if the weights aren't being specified. Weights have no influence on
+ * the selection of the first row filter. Well chosen weights can (in theory)
+ * improve the compression for a given image.
+ *
+ * Costs are factors >= 1.0 indicating the relative decoding costs of a
+ * filter type. Higher costs indicate more decoding expense, and are
+ * therefore less likely to be selected over a filter with lower computational
+ * costs. There needs to be a value in "filter_costs" for each valid filter
+ * type (given by PNG_FILTER_VALUE_LAST), or it can be NULL if you aren't
+ * setting the costs. Costs try to improve the speed of decompression without
+ * unduly increasing the compressed image size.
+ *
+ * A negative weight or cost indicates the default value is to be used, and
+ * values in the range [0.0, 1.0) indicate the value is to remain unchanged.
+ * The default values for both weights and costs are currently 1.0, but may
+ * change if good general weighting/cost heuristics can be found. If both
+ * the weights and costs are set to 1.0, this degenerates the WEIGHTED method
+ * to the UNWEIGHTED method, but with added encoding time/computation.
+ */
+PNG_FP_EXPORT(68, void, png_set_filter_heuristics, (png_structrp png_ptr,
+ int heuristic_method, int num_weights, png_const_doublep filter_weights,
+ png_const_doublep filter_costs))
+PNG_FIXED_EXPORT(209, void, png_set_filter_heuristics_fixed,
+ (png_structrp png_ptr, int heuristic_method, int num_weights,
+ png_const_fixed_point_p filter_weights,
+ png_const_fixed_point_p filter_costs))
+#endif /* WRITE_WEIGHTED_FILTER */
+
+/* Heuristic used for row filter selection. These defines should NOT be
+ * changed.
+ */
+#define PNG_FILTER_HEURISTIC_DEFAULT 0 /* Currently "UNWEIGHTED" */
+#define PNG_FILTER_HEURISTIC_UNWEIGHTED 1 /* Used by libpng < 0.95 */
+#define PNG_FILTER_HEURISTIC_WEIGHTED 2 /* Experimental feature */
+#define PNG_FILTER_HEURISTIC_LAST 3 /* Not a valid value */
+
+/* Set the library compression level. Currently, valid values range from
+ * 0 - 9, corresponding directly to the zlib compression levels 0 - 9
+ * (0 - no compression, 9 - "maximal" compression). Note that tests have
+ * shown that zlib compression levels 3-6 usually perform as well as level 9
+ * for PNG images, and do considerably fewer caclulations. In the future,
+ * these values may not correspond directly to the zlib compression levels.
+ */
+#ifdef PNG_WRITE_CUSTOMIZE_COMPRESSION_SUPPORTED
+PNG_EXPORT(69, void, png_set_compression_level, (png_structrp png_ptr,
+ int level));
+
+PNG_EXPORT(70, void, png_set_compression_mem_level, (png_structrp png_ptr,
+ int mem_level));
+
+PNG_EXPORT(71, void, png_set_compression_strategy, (png_structrp png_ptr,
+ int strategy));
+
+/* If PNG_WRITE_OPTIMIZE_CMF_SUPPORTED is defined, libpng will use a
+ * smaller value of window_bits if it can do so safely.
+ */
+PNG_EXPORT(72, void, png_set_compression_window_bits, (png_structrp png_ptr,
+ int window_bits));
+
+PNG_EXPORT(73, void, png_set_compression_method, (png_structrp png_ptr,
+ int method));
+#endif /* WRITE_CUSTOMIZE_COMPRESSION */
+
+#ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED
+/* Also set zlib parameters for compressing non-IDAT chunks */
+PNG_EXPORT(222, void, png_set_text_compression_level, (png_structrp png_ptr,
+ int level));
+
+PNG_EXPORT(223, void, png_set_text_compression_mem_level, (png_structrp png_ptr,
+ int mem_level));
+
+PNG_EXPORT(224, void, png_set_text_compression_strategy, (png_structrp png_ptr,
+ int strategy));
+
+/* If PNG_WRITE_OPTIMIZE_CMF_SUPPORTED is defined, libpng will use a
+ * smaller value of window_bits if it can do so safely.
+ */
+PNG_EXPORT(225, void, png_set_text_compression_window_bits,
+ (png_structrp png_ptr, int window_bits));
+
+PNG_EXPORT(226, void, png_set_text_compression_method, (png_structrp png_ptr,
+ int method));
+#endif /* WRITE_CUSTOMIZE_ZTXT_COMPRESSION */
+#endif /* WRITE */
+
+/* These next functions are called for input/output, memory, and error
+ * handling. They are in the file pngrio.c, pngwio.c, and pngerror.c,
+ * and call standard C I/O routines such as fread(), fwrite(), and
+ * fprintf(). These functions can be made to use other I/O routines
+ * at run time for those applications that need to handle I/O in a
+ * different manner by calling png_set_???_fn(). See libpng-manual.txt for
+ * more information.
+ */
+
+#ifdef PNG_STDIO_SUPPORTED
+/* Initialize the input/output for the PNG file to the default functions. */
+PNG_EXPORT(74, void, png_init_io, (png_structrp png_ptr, png_FILE_p fp));
+#endif
+
+/* Replace the (error and abort), and warning functions with user
+ * supplied functions. If no messages are to be printed you must still
+ * write and use replacement functions. The replacement error_fn should
+ * still do a longjmp to the last setjmp location if you are using this
+ * method of error handling. If error_fn or warning_fn is NULL, the
+ * default function will be used.
+ */
+
+PNG_EXPORT(75, void, png_set_error_fn, (png_structrp png_ptr,
+ png_voidp error_ptr, png_error_ptr error_fn, png_error_ptr warning_fn));
+
+/* Return the user pointer associated with the error functions */
+PNG_EXPORT(76, png_voidp, png_get_error_ptr, (png_const_structrp png_ptr));
+
+/* Replace the default data output functions with a user supplied one(s).
+ * If buffered output is not used, then output_flush_fn can be set to NULL.
+ * If PNG_WRITE_FLUSH_SUPPORTED is not defined at libpng compile time
+ * output_flush_fn will be ignored (and thus can be NULL).
+ * It is probably a mistake to use NULL for output_flush_fn if
+ * write_data_fn is not also NULL unless you have built libpng with
+ * PNG_WRITE_FLUSH_SUPPORTED undefined, because in this case libpng's
+ * default flush function, which uses the standard *FILE structure, will
+ * be used.
+ */
+PNG_EXPORT(77, void, png_set_write_fn, (png_structrp png_ptr, png_voidp io_ptr,
+ png_rw_ptr write_data_fn, png_flush_ptr output_flush_fn));
+
+/* Replace the default data input function with a user supplied one. */
+PNG_EXPORT(78, void, png_set_read_fn, (png_structrp png_ptr, png_voidp io_ptr,
+ png_rw_ptr read_data_fn));
+
+/* Return the user pointer associated with the I/O functions */
+PNG_EXPORT(79, png_voidp, png_get_io_ptr, (png_const_structrp png_ptr));
+
+PNG_EXPORT(80, void, png_set_read_status_fn, (png_structrp png_ptr,
+ png_read_status_ptr read_row_fn));
+
+PNG_EXPORT(81, void, png_set_write_status_fn, (png_structrp png_ptr,
+ png_write_status_ptr write_row_fn));
+
+#ifdef PNG_USER_MEM_SUPPORTED
+/* Replace the default memory allocation functions with user supplied one(s). */
+PNG_EXPORT(82, void, png_set_mem_fn, (png_structrp png_ptr, png_voidp mem_ptr,
+ png_malloc_ptr malloc_fn, png_free_ptr free_fn));
+/* Return the user pointer associated with the memory functions */
+PNG_EXPORT(83, png_voidp, png_get_mem_ptr, (png_const_structrp png_ptr));
+#endif
+
+#ifdef PNG_READ_USER_TRANSFORM_SUPPORTED
+PNG_EXPORT(84, void, png_set_read_user_transform_fn, (png_structrp png_ptr,
+ png_user_transform_ptr read_user_transform_fn));
+#endif
+
+#ifdef PNG_WRITE_USER_TRANSFORM_SUPPORTED
+PNG_EXPORT(85, void, png_set_write_user_transform_fn, (png_structrp png_ptr,
+ png_user_transform_ptr write_user_transform_fn));
+#endif
+
+#ifdef PNG_USER_TRANSFORM_PTR_SUPPORTED
+PNG_EXPORT(86, void, png_set_user_transform_info, (png_structrp png_ptr,
+ png_voidp user_transform_ptr, int user_transform_depth,
+ int user_transform_channels));
+/* Return the user pointer associated with the user transform functions */
+PNG_EXPORT(87, png_voidp, png_get_user_transform_ptr,
+ (png_const_structrp png_ptr));
+#endif
+
+#ifdef PNG_USER_TRANSFORM_INFO_SUPPORTED
+/* Return information about the row currently being processed. Note that these
+ * APIs do not fail but will return unexpected results if called outside a user
+ * transform callback. Also note that when transforming an interlaced image the
+ * row number is the row number within the sub-image of the interlace pass, so
+ * the value will increase to the height of the sub-image (not the full image)
+ * then reset to 0 for the next pass.
+ *
+ * Use PNG_ROW_FROM_PASS_ROW(row, pass) and PNG_COL_FROM_PASS_COL(col, pass) to
+ * find the output pixel (x,y) given an interlaced sub-image pixel
+ * (row,col,pass). (See below for these macros.)
+ */
+PNG_EXPORT(217, png_uint_32, png_get_current_row_number, (png_const_structrp));
+PNG_EXPORT(218, png_byte, png_get_current_pass_number, (png_const_structrp));
+#endif
+
+#ifdef PNG_READ_USER_CHUNKS_SUPPORTED
+/* This callback is called only for *unknown* chunks. If
+ * PNG_HANDLE_AS_UNKNOWN_SUPPORTED is set then it is possible to set known
+ * chunks to be treated as unknown, however in this case the callback must do
+ * any processing required by the chunk (e.g. by calling the appropriate
+ * png_set_ APIs.)
+ *
+ * There is no write support - on write, by default, all the chunks in the
+ * 'unknown' list are written in the specified position.
+ *
+ * The integer return from the callback function is interpreted thus:
+ *
+ * negative: An error occurred; png_chunk_error will be called.
+ * zero: The chunk was not handled, the chunk will be saved. A critical
+ * chunk will cause an error at this point unless it is to be saved.
+ * positive: The chunk was handled, libpng will ignore/discard it.
+ *
+ * See "INTERACTION WTIH USER CHUNK CALLBACKS" below for important notes about
+ * how this behavior will change in libpng 1.7
+ */
+PNG_EXPORT(88, void, png_set_read_user_chunk_fn, (png_structrp png_ptr,
+ png_voidp user_chunk_ptr, png_user_chunk_ptr read_user_chunk_fn));
+#endif
+
+#ifdef PNG_USER_CHUNKS_SUPPORTED
+PNG_EXPORT(89, png_voidp, png_get_user_chunk_ptr, (png_const_structrp png_ptr));
+#endif
+
+#ifdef PNG_PROGRESSIVE_READ_SUPPORTED
+/* Sets the function callbacks for the push reader, and a pointer to a
+ * user-defined structure available to the callback functions.
+ */
+PNG_EXPORT(90, void, png_set_progressive_read_fn, (png_structrp png_ptr,
+ png_voidp progressive_ptr, png_progressive_info_ptr info_fn,
+ png_progressive_row_ptr row_fn, png_progressive_end_ptr end_fn));
+
+/* Returns the user pointer associated with the push read functions */
+PNG_EXPORT(91, png_voidp, png_get_progressive_ptr,
+ (png_const_structrp png_ptr));
+
+/* Function to be called when data becomes available */
+PNG_EXPORT(92, void, png_process_data, (png_structrp png_ptr,
+ png_inforp info_ptr, png_bytep buffer, png_size_t buffer_size));
+
+/* A function which may be called *only* within png_process_data to stop the
+ * processing of any more data. The function returns the number of bytes
+ * remaining, excluding any that libpng has cached internally. A subsequent
+ * call to png_process_data must supply these bytes again. If the argument
+ * 'save' is set to true the routine will first save all the pending data and
+ * will always return 0.
+ */
+PNG_EXPORT(219, png_size_t, png_process_data_pause, (png_structrp, int save));
+
+/* A function which may be called *only* outside (after) a call to
+ * png_process_data. It returns the number of bytes of data to skip in the
+ * input. Normally it will return 0, but if it returns a non-zero value the
+ * application must skip than number of bytes of input data and pass the
+ * following data to the next call to png_process_data.
+ */
+PNG_EXPORT(220, png_uint_32, png_process_data_skip, (png_structrp));
+
+/* Function that combines rows. 'new_row' is a flag that should come from
+ * the callback and be non-NULL if anything needs to be done; the library
+ * stores its own version of the new data internally and ignores the passed
+ * in value.
+ */
+PNG_EXPORT(93, void, png_progressive_combine_row, (png_const_structrp png_ptr,
+ png_bytep old_row, png_const_bytep new_row));
+#endif /* PROGRESSIVE_READ */
+
+PNG_EXPORTA(94, png_voidp, png_malloc, (png_const_structrp png_ptr,
+ png_alloc_size_t size), PNG_ALLOCATED);
+/* Added at libpng version 1.4.0 */
+PNG_EXPORTA(95, png_voidp, png_calloc, (png_const_structrp png_ptr,
+ png_alloc_size_t size), PNG_ALLOCATED);
+
+/* Added at libpng version 1.2.4 */
+PNG_EXPORTA(96, png_voidp, png_malloc_warn, (png_const_structrp png_ptr,
+ png_alloc_size_t size), PNG_ALLOCATED);
+
+/* Frees a pointer allocated by png_malloc() */
+PNG_EXPORT(97, void, png_free, (png_const_structrp png_ptr, png_voidp ptr));
+
+/* Free data that was allocated internally */
+PNG_EXPORT(98, void, png_free_data, (png_const_structrp png_ptr,
+ png_inforp info_ptr, png_uint_32 free_me, int num));
+
+/* Reassign responsibility for freeing existing data, whether allocated
+ * by libpng or by the application; this works on the png_info structure passed
+ * in, it does not change the state for other png_info structures.
+ *
+ * It is unlikely that this function works correctly as of 1.6.0 and using it
+ * may result either in memory leaks or double free of allocated data.
+ */
+PNG_EXPORT(99, void, png_data_freer, (png_const_structrp png_ptr,
+ png_inforp info_ptr, int freer, png_uint_32 mask));
+
+/* Assignments for png_data_freer */
+#define PNG_DESTROY_WILL_FREE_DATA 1
+#define PNG_SET_WILL_FREE_DATA 1
+#define PNG_USER_WILL_FREE_DATA 2
+/* Flags for png_ptr->free_me and info_ptr->free_me */
+#define PNG_FREE_HIST 0x0008
+#define PNG_FREE_ICCP 0x0010
+#define PNG_FREE_SPLT 0x0020
+#define PNG_FREE_ROWS 0x0040
+#define PNG_FREE_PCAL 0x0080
+#define PNG_FREE_SCAL 0x0100
+#ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED
+# define PNG_FREE_UNKN 0x0200
+#endif
+/* PNG_FREE_LIST 0x0400 removed in 1.6.0 because it is ignored */
+#define PNG_FREE_PLTE 0x1000
+#define PNG_FREE_TRNS 0x2000
+#define PNG_FREE_TEXT 0x4000
+#define PNG_FREE_ALL 0x7fff
+#define PNG_FREE_MUL 0x4220 /* PNG_FREE_SPLT|PNG_FREE_TEXT|PNG_FREE_UNKN */
+
+#ifdef PNG_USER_MEM_SUPPORTED
+PNG_EXPORTA(100, png_voidp, png_malloc_default, (png_const_structrp png_ptr,
+ png_alloc_size_t size), PNG_ALLOCATED PNG_DEPRECATED);
+PNG_EXPORTA(101, void, png_free_default, (png_const_structrp png_ptr,
+ png_voidp ptr), PNG_DEPRECATED);
+#endif
+
+#ifdef PNG_ERROR_TEXT_SUPPORTED
+/* Fatal error in PNG image of libpng - can't continue */
+PNG_EXPORTA(102, void, png_error, (png_const_structrp png_ptr,
+ png_const_charp error_message), PNG_NORETURN);
+
+/* The same, but the chunk name is prepended to the error string. */
+PNG_EXPORTA(103, void, png_chunk_error, (png_const_structrp png_ptr,
+ png_const_charp error_message), PNG_NORETURN);
+
+#else
+/* Fatal error in PNG image of libpng - can't continue */
+PNG_EXPORTA(104, void, png_err, (png_const_structrp png_ptr), PNG_NORETURN);
+# define png_error(s1,s2) png_err(s1)
+# define png_chunk_error(s1,s2) png_err(s1)
+#endif
+
+#ifdef PNG_WARNINGS_SUPPORTED
+/* Non-fatal error in libpng. Can continue, but may have a problem. */
+PNG_EXPORT(105, void, png_warning, (png_const_structrp png_ptr,
+ png_const_charp warning_message));
+
+/* Non-fatal error in libpng, chunk name is prepended to message. */
+PNG_EXPORT(106, void, png_chunk_warning, (png_const_structrp png_ptr,
+ png_const_charp warning_message));
+#else
+# define png_warning(s1,s2) ((void)(s1))
+# define png_chunk_warning(s1,s2) ((void)(s1))
+#endif
+
+#ifdef PNG_BENIGN_ERRORS_SUPPORTED
+/* Benign error in libpng. Can continue, but may have a problem.
+ * User can choose whether to handle as a fatal error or as a warning. */
+PNG_EXPORT(107, void, png_benign_error, (png_const_structrp png_ptr,
+ png_const_charp warning_message));
+
+#ifdef PNG_READ_SUPPORTED
+/* Same, chunk name is prepended to message (only during read) */
+PNG_EXPORT(108, void, png_chunk_benign_error, (png_const_structrp png_ptr,
+ png_const_charp warning_message));
+#endif
+
+PNG_EXPORT(109, void, png_set_benign_errors,
+ (png_structrp png_ptr, int allowed));
+#else
+# ifdef PNG_ALLOW_BENIGN_ERRORS
+# define png_benign_error png_warning
+# define png_chunk_benign_error png_chunk_warning
+# else
+# define png_benign_error png_error
+# define png_chunk_benign_error png_chunk_error
+# endif
+#endif
+
+/* The png_set_<chunk> functions are for storing values in the png_info_struct.
+ * Similarly, the png_get_<chunk> calls are used to read values from the
+ * png_info_struct, either storing the parameters in the passed variables, or
+ * setting pointers into the png_info_struct where the data is stored. The
+ * png_get_<chunk> functions return a non-zero value if the data was available
+ * in info_ptr, or return zero and do not change any of the parameters if the
+ * data was not available.
+ *
+ * These functions should be used instead of directly accessing png_info
+ * to avoid problems with future changes in the size and internal layout of
+ * png_info_struct.
+ */
+/* Returns "flag" if chunk data is valid in info_ptr. */
+PNG_EXPORT(110, png_uint_32, png_get_valid, (png_const_structrp png_ptr,
+ png_const_inforp info_ptr, png_uint_32 flag));
+
+/* Returns number of bytes needed to hold a transformed row. */
+PNG_EXPORT(111, png_size_t, png_get_rowbytes, (png_const_structrp png_ptr,
+ png_const_inforp info_ptr));
+
+#ifdef PNG_INFO_IMAGE_SUPPORTED
+/* Returns row_pointers, which is an array of pointers to scanlines that was
+ * returned from png_read_png().
+ */
+PNG_EXPORT(112, png_bytepp, png_get_rows, (png_const_structrp png_ptr,
+ png_const_inforp info_ptr));
+
+/* Set row_pointers, which is an array of pointers to scanlines for use
+ * by png_write_png().
+ */
+PNG_EXPORT(113, void, png_set_rows, (png_const_structrp png_ptr,
+ png_inforp info_ptr, png_bytepp row_pointers));
+#endif
+
+/* Returns number of color channels in image. */
+PNG_EXPORT(114, png_byte, png_get_channels, (png_const_structrp png_ptr,
+ png_const_inforp info_ptr));
+
+#ifdef PNG_EASY_ACCESS_SUPPORTED
+/* Returns image width in pixels. */
+PNG_EXPORT(115, png_uint_32, png_get_image_width, (png_const_structrp png_ptr,
+ png_const_inforp info_ptr));
+
+/* Returns image height in pixels. */
+PNG_EXPORT(116, png_uint_32, png_get_image_height, (png_const_structrp png_ptr,
+ png_const_inforp info_ptr));
+
+/* Returns image bit_depth. */
+PNG_EXPORT(117, png_byte, png_get_bit_depth, (png_const_structrp png_ptr,
+ png_const_inforp info_ptr));
+
+/* Returns image color_type. */
+PNG_EXPORT(118, png_byte, png_get_color_type, (png_const_structrp png_ptr,
+ png_const_inforp info_ptr));
+
+/* Returns image filter_type. */
+PNG_EXPORT(119, png_byte, png_get_filter_type, (png_const_structrp png_ptr,
+ png_const_inforp info_ptr));
+
+/* Returns image interlace_type. */
+PNG_EXPORT(120, png_byte, png_get_interlace_type, (png_const_structrp png_ptr,
+ png_const_inforp info_ptr));
+
+/* Returns image compression_type. */
+PNG_EXPORT(121, png_byte, png_get_compression_type, (png_const_structrp png_ptr,
+ png_const_inforp info_ptr));
+
+/* Returns image resolution in pixels per meter, from pHYs chunk data. */
+PNG_EXPORT(122, png_uint_32, png_get_pixels_per_meter,
+ (png_const_structrp png_ptr, png_const_inforp info_ptr));
+PNG_EXPORT(123, png_uint_32, png_get_x_pixels_per_meter,
+ (png_const_structrp png_ptr, png_const_inforp info_ptr));
+PNG_EXPORT(124, png_uint_32, png_get_y_pixels_per_meter,
+ (png_const_structrp png_ptr, png_const_inforp info_ptr));
+
+/* Returns pixel aspect ratio, computed from pHYs chunk data. */
+PNG_FP_EXPORT(125, float, png_get_pixel_aspect_ratio,
+ (png_const_structrp png_ptr, png_const_inforp info_ptr))
+PNG_FIXED_EXPORT(210, png_fixed_point, png_get_pixel_aspect_ratio_fixed,
+ (png_const_structrp png_ptr, png_const_inforp info_ptr))
+
+/* Returns image x, y offset in pixels or microns, from oFFs chunk data. */
+PNG_EXPORT(126, png_int_32, png_get_x_offset_pixels,
+ (png_const_structrp png_ptr, png_const_inforp info_ptr));
+PNG_EXPORT(127, png_int_32, png_get_y_offset_pixels,
+ (png_const_structrp png_ptr, png_const_inforp info_ptr));
+PNG_EXPORT(128, png_int_32, png_get_x_offset_microns,
+ (png_const_structrp png_ptr, png_const_inforp info_ptr));
+PNG_EXPORT(129, png_int_32, png_get_y_offset_microns,
+ (png_const_structrp png_ptr, png_const_inforp info_ptr));
+
+#endif /* EASY_ACCESS */
+
+#ifdef PNG_READ_SUPPORTED
+/* Returns pointer to signature string read from PNG header */
+PNG_EXPORT(130, png_const_bytep, png_get_signature, (png_const_structrp png_ptr,
+ png_const_inforp info_ptr));
+#endif
+
+#ifdef PNG_bKGD_SUPPORTED
+PNG_EXPORT(131, png_uint_32, png_get_bKGD, (png_const_structrp png_ptr,
+ png_inforp info_ptr, png_color_16p *background));
+#endif
+
+#ifdef PNG_bKGD_SUPPORTED
+PNG_EXPORT(132, void, png_set_bKGD, (png_const_structrp png_ptr,
+ png_inforp info_ptr, png_const_color_16p background));
+#endif
+
+#ifdef PNG_cHRM_SUPPORTED
+PNG_FP_EXPORT(133, png_uint_32, png_get_cHRM, (png_const_structrp png_ptr,
+ png_const_inforp info_ptr, double *white_x, double *white_y, double *red_x,
+ double *red_y, double *green_x, double *green_y, double *blue_x,
+ double *blue_y))
+PNG_FP_EXPORT(230, png_uint_32, png_get_cHRM_XYZ, (png_const_structrp png_ptr,
+ png_const_inforp info_ptr, double *red_X, double *red_Y, double *red_Z,
+ double *green_X, double *green_Y, double *green_Z, double *blue_X,
+ double *blue_Y, double *blue_Z))
+PNG_FIXED_EXPORT(134, png_uint_32, png_get_cHRM_fixed,
+ (png_const_structrp png_ptr, png_const_inforp info_ptr,
+ png_fixed_point *int_white_x, png_fixed_point *int_white_y,
+ png_fixed_point *int_red_x, png_fixed_point *int_red_y,
+ png_fixed_point *int_green_x, png_fixed_point *int_green_y,
+ png_fixed_point *int_blue_x, png_fixed_point *int_blue_y))
+PNG_FIXED_EXPORT(231, png_uint_32, png_get_cHRM_XYZ_fixed,
+ (png_const_structrp png_ptr, png_const_inforp info_ptr,
+ png_fixed_point *int_red_X, png_fixed_point *int_red_Y,
+ png_fixed_point *int_red_Z, png_fixed_point *int_green_X,
+ png_fixed_point *int_green_Y, png_fixed_point *int_green_Z,
+ png_fixed_point *int_blue_X, png_fixed_point *int_blue_Y,
+ png_fixed_point *int_blue_Z))
+#endif
+
+#ifdef PNG_cHRM_SUPPORTED
+PNG_FP_EXPORT(135, void, png_set_cHRM, (png_const_structrp png_ptr,
+ png_inforp info_ptr,
+ double white_x, double white_y, double red_x, double red_y, double green_x,
+ double green_y, double blue_x, double blue_y))
+PNG_FP_EXPORT(232, void, png_set_cHRM_XYZ, (png_const_structrp png_ptr,
+ png_inforp info_ptr, double red_X, double red_Y, double red_Z,
+ double green_X, double green_Y, double green_Z, double blue_X,
+ double blue_Y, double blue_Z))
+PNG_FIXED_EXPORT(136, void, png_set_cHRM_fixed, (png_const_structrp png_ptr,
+ png_inforp info_ptr, png_fixed_point int_white_x,
+ png_fixed_point int_white_y, png_fixed_point int_red_x,
+ png_fixed_point int_red_y, png_fixed_point int_green_x,
+ png_fixed_point int_green_y, png_fixed_point int_blue_x,
+ png_fixed_point int_blue_y))
+PNG_FIXED_EXPORT(233, void, png_set_cHRM_XYZ_fixed, (png_const_structrp png_ptr,
+ png_inforp info_ptr, png_fixed_point int_red_X, png_fixed_point int_red_Y,
+ png_fixed_point int_red_Z, png_fixed_point int_green_X,
+ png_fixed_point int_green_Y, png_fixed_point int_green_Z,
+ png_fixed_point int_blue_X, png_fixed_point int_blue_Y,
+ png_fixed_point int_blue_Z))
+#endif
+
+#ifdef PNG_gAMA_SUPPORTED
+PNG_FP_EXPORT(137, png_uint_32, png_get_gAMA, (png_const_structrp png_ptr,
+ png_const_inforp info_ptr, double *file_gamma))
+PNG_FIXED_EXPORT(138, png_uint_32, png_get_gAMA_fixed,
+ (png_const_structrp png_ptr, png_const_inforp info_ptr,
+ png_fixed_point *int_file_gamma))
+#endif
+
+#ifdef PNG_gAMA_SUPPORTED
+PNG_FP_EXPORT(139, void, png_set_gAMA, (png_const_structrp png_ptr,
+ png_inforp info_ptr, double file_gamma))
+PNG_FIXED_EXPORT(140, void, png_set_gAMA_fixed, (png_const_structrp png_ptr,
+ png_inforp info_ptr, png_fixed_point int_file_gamma))
+#endif
+
+#ifdef PNG_hIST_SUPPORTED
+PNG_EXPORT(141, png_uint_32, png_get_hIST, (png_const_structrp png_ptr,
+ png_inforp info_ptr, png_uint_16p *hist));
+#endif
+
+#ifdef PNG_hIST_SUPPORTED
+PNG_EXPORT(142, void, png_set_hIST, (png_const_structrp png_ptr,
+ png_inforp info_ptr, png_const_uint_16p hist));
+#endif
+
+PNG_EXPORT(143, png_uint_32, png_get_IHDR, (png_const_structrp png_ptr,
+ png_const_inforp info_ptr, png_uint_32 *width, png_uint_32 *height,
+ int *bit_depth, int *color_type, int *interlace_method,
+ int *compression_method, int *filter_method));
+
+PNG_EXPORT(144, void, png_set_IHDR, (png_const_structrp png_ptr,
+ png_inforp info_ptr, png_uint_32 width, png_uint_32 height, int bit_depth,
+ int color_type, int interlace_method, int compression_method,
+ int filter_method));
+
+#ifdef PNG_oFFs_SUPPORTED
+PNG_EXPORT(145, png_uint_32, png_get_oFFs, (png_const_structrp png_ptr,
+ png_const_inforp info_ptr, png_int_32 *offset_x, png_int_32 *offset_y,
+ int *unit_type));
+#endif
+
+#ifdef PNG_oFFs_SUPPORTED
+PNG_EXPORT(146, void, png_set_oFFs, (png_const_structrp png_ptr,
+ png_inforp info_ptr, png_int_32 offset_x, png_int_32 offset_y,
+ int unit_type));
+#endif
+
+#ifdef PNG_pCAL_SUPPORTED
+PNG_EXPORT(147, png_uint_32, png_get_pCAL, (png_const_structrp png_ptr,
+ png_inforp info_ptr, png_charp *purpose, png_int_32 *X0,
+ png_int_32 *X1, int *type, int *nparams, png_charp *units,
+ png_charpp *params));
+#endif
+
+#ifdef PNG_pCAL_SUPPORTED
+PNG_EXPORT(148, void, png_set_pCAL, (png_const_structrp png_ptr,
+ png_inforp info_ptr, png_const_charp purpose, png_int_32 X0, png_int_32 X1,
+ int type, int nparams, png_const_charp units, png_charpp params));
+#endif
+
+#ifdef PNG_pHYs_SUPPORTED
+PNG_EXPORT(149, png_uint_32, png_get_pHYs, (png_const_structrp png_ptr,
+ png_const_inforp info_ptr, png_uint_32 *res_x, png_uint_32 *res_y,
+ int *unit_type));
+#endif
+
+#ifdef PNG_pHYs_SUPPORTED
+PNG_EXPORT(150, void, png_set_pHYs, (png_const_structrp png_ptr,
+ png_inforp info_ptr, png_uint_32 res_x, png_uint_32 res_y, int unit_type));
+#endif
+
+PNG_EXPORT(151, png_uint_32, png_get_PLTE, (png_const_structrp png_ptr,
+ png_inforp info_ptr, png_colorp *palette, int *num_palette));
+
+PNG_EXPORT(152, void, png_set_PLTE, (png_structrp png_ptr,
+ png_inforp info_ptr, png_const_colorp palette, int num_palette));
+
+#ifdef PNG_sBIT_SUPPORTED
+PNG_EXPORT(153, png_uint_32, png_get_sBIT, (png_const_structrp png_ptr,
+ png_inforp info_ptr, png_color_8p *sig_bit));
+#endif
+
+#ifdef PNG_sBIT_SUPPORTED
+PNG_EXPORT(154, void, png_set_sBIT, (png_const_structrp png_ptr,
+ png_inforp info_ptr, png_const_color_8p sig_bit));
+#endif
+
+#ifdef PNG_sRGB_SUPPORTED
+PNG_EXPORT(155, png_uint_32, png_get_sRGB, (png_const_structrp png_ptr,
+ png_const_inforp info_ptr, int *file_srgb_intent));
+#endif
+
+#ifdef PNG_sRGB_SUPPORTED
+PNG_EXPORT(156, void, png_set_sRGB, (png_const_structrp png_ptr,
+ png_inforp info_ptr, int srgb_intent));
+PNG_EXPORT(157, void, png_set_sRGB_gAMA_and_cHRM, (png_const_structrp png_ptr,
+ png_inforp info_ptr, int srgb_intent));
+#endif
+
+#ifdef PNG_iCCP_SUPPORTED
+PNG_EXPORT(158, png_uint_32, png_get_iCCP, (png_const_structrp png_ptr,
+ png_inforp info_ptr, png_charpp name, int *compression_type,
+ png_bytepp profile, png_uint_32 *proflen));
+#endif
+
+#ifdef PNG_iCCP_SUPPORTED
+PNG_EXPORT(159, void, png_set_iCCP, (png_const_structrp png_ptr,
+ png_inforp info_ptr, png_const_charp name, int compression_type,
+ png_const_bytep profile, png_uint_32 proflen));
+#endif
+
+#ifdef PNG_sPLT_SUPPORTED
+PNG_EXPORT(160, int, png_get_sPLT, (png_const_structrp png_ptr,
+ png_inforp info_ptr, png_sPLT_tpp entries));
+#endif
+
+#ifdef PNG_sPLT_SUPPORTED
+PNG_EXPORT(161, void, png_set_sPLT, (png_const_structrp png_ptr,
+ png_inforp info_ptr, png_const_sPLT_tp entries, int nentries));
+#endif
+
+#ifdef PNG_TEXT_SUPPORTED
+/* png_get_text also returns the number of text chunks in *num_text */
+PNG_EXPORT(162, int, png_get_text, (png_const_structrp png_ptr,
+ png_inforp info_ptr, png_textp *text_ptr, int *num_text));
+#endif
+
+/* Note while png_set_text() will accept a structure whose text,
+ * language, and translated keywords are NULL pointers, the structure
+ * returned by png_get_text will always contain regular
+ * zero-terminated C strings. They might be empty strings but
+ * they will never be NULL pointers.
+ */
+
+#ifdef PNG_TEXT_SUPPORTED
+PNG_EXPORT(163, void, png_set_text, (png_const_structrp png_ptr,
+ png_inforp info_ptr, png_const_textp text_ptr, int num_text));
+#endif
+
+#ifdef PNG_tIME_SUPPORTED
+PNG_EXPORT(164, png_uint_32, png_get_tIME, (png_const_structrp png_ptr,
+ png_inforp info_ptr, png_timep *mod_time));
+#endif
+
+#ifdef PNG_tIME_SUPPORTED
+PNG_EXPORT(165, void, png_set_tIME, (png_const_structrp png_ptr,
+ png_inforp info_ptr, png_const_timep mod_time));
+#endif
+
+#ifdef PNG_tRNS_SUPPORTED
+PNG_EXPORT(166, png_uint_32, png_get_tRNS, (png_const_structrp png_ptr,
+ png_inforp info_ptr, png_bytep *trans_alpha, int *num_trans,
+ png_color_16p *trans_color));
+#endif
+
+#ifdef PNG_tRNS_SUPPORTED
+PNG_EXPORT(167, void, png_set_tRNS, (png_structrp png_ptr,
+ png_inforp info_ptr, png_const_bytep trans_alpha, int num_trans,
+ png_const_color_16p trans_color));
+#endif
+
+#ifdef PNG_sCAL_SUPPORTED
+PNG_FP_EXPORT(168, png_uint_32, png_get_sCAL, (png_const_structrp png_ptr,
+ png_const_inforp info_ptr, int *unit, double *width, double *height))
+#if defined(PNG_FLOATING_ARITHMETIC_SUPPORTED) || \
+ defined(PNG_FLOATING_POINT_SUPPORTED)
+/* NOTE: this API is currently implemented using floating point arithmetic,
+ * consequently it can only be used on systems with floating point support.
+ * In any case the range of values supported by png_fixed_point is small and it
+ * is highly recommended that png_get_sCAL_s be used instead.
+ */
+PNG_FIXED_EXPORT(214, png_uint_32, png_get_sCAL_fixed,
+ (png_const_structrp png_ptr, png_const_inforp info_ptr, int *unit,
+ png_fixed_point *width, png_fixed_point *height))
+#endif
+PNG_EXPORT(169, png_uint_32, png_get_sCAL_s,
+ (png_const_structrp png_ptr, png_const_inforp info_ptr, int *unit,
+ png_charpp swidth, png_charpp sheight));
+
+PNG_FP_EXPORT(170, void, png_set_sCAL, (png_const_structrp png_ptr,
+ png_inforp info_ptr, int unit, double width, double height))
+PNG_FIXED_EXPORT(213, void, png_set_sCAL_fixed, (png_const_structrp png_ptr,
+ png_inforp info_ptr, int unit, png_fixed_point width,
+ png_fixed_point height))
+PNG_EXPORT(171, void, png_set_sCAL_s, (png_const_structrp png_ptr,
+ png_inforp info_ptr, int unit,
+ png_const_charp swidth, png_const_charp sheight));
+#endif /* sCAL */
+
+#ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
+/* Provide the default handling for all unknown chunks or, optionally, for
+ * specific unknown chunks.
+ *
+ * NOTE: prior to 1.6.0 the handling specified for particular chunks on read was
+ * ignored and the default was used, the per-chunk setting only had an effect on
+ * write. If you wish to have chunk-specific handling on read in code that must
+ * work on earlier versions you must use a user chunk callback to specify the
+ * desired handling (keep or discard.)
+ *
+ * The 'keep' parameter is a PNG_HANDLE_CHUNK_ value as listed below. The
+ * parameter is interpreted as follows:
+ *
+ * READ:
+ * PNG_HANDLE_CHUNK_AS_DEFAULT:
+ * Known chunks: do normal libpng processing, do not keep the chunk (but
+ * see the comments below about PNG_HANDLE_AS_UNKNOWN_SUPPORTED)
+ * Unknown chunks: for a specific chunk use the global default, when used
+ * as the default discard the chunk data.
+ * PNG_HANDLE_CHUNK_NEVER:
+ * Discard the chunk data.
+ * PNG_HANDLE_CHUNK_IF_SAFE:
+ * Keep the chunk data if the chunk is not critical else raise a chunk
+ * error.
+ * PNG_HANDLE_CHUNK_ALWAYS:
+ * Keep the chunk data.
+ *
+ * If the chunk data is saved it can be retrieved using png_get_unknown_chunks,
+ * below. Notice that specifying "AS_DEFAULT" as a global default is equivalent
+ * to specifying "NEVER", however when "AS_DEFAULT" is used for specific chunks
+ * it simply resets the behavior to the libpng default.
+ *
+ * INTERACTION WTIH USER CHUNK CALLBACKS:
+ * The per-chunk handling is always used when there is a png_user_chunk_ptr
+ * callback and the callback returns 0; the chunk is then always stored *unless*
+ * it is critical and the per-chunk setting is other than ALWAYS. Notice that
+ * the global default is *not* used in this case. (In effect the per-chunk
+ * value is incremented to at least IF_SAFE.)
+ *
+ * IMPORTANT NOTE: this behavior will change in libpng 1.7 - the global and
+ * per-chunk defaults will be honored. If you want to preserve the current
+ * behavior when your callback returns 0 you must set PNG_HANDLE_CHUNK_IF_SAFE
+ * as the default - if you don't do this libpng 1.6 will issue a warning.
+ *
+ * If you want unhandled unknown chunks to be discarded in libpng 1.6 and
+ * earlier simply return '1' (handled).
+ *
+ * PNG_HANDLE_AS_UNKNOWN_SUPPORTED:
+ * If this is *not* set known chunks will always be handled by libpng and
+ * will never be stored in the unknown chunk list. Known chunks listed to
+ * png_set_keep_unknown_chunks will have no effect. If it is set then known
+ * chunks listed with a keep other than AS_DEFAULT will *never* be processed
+ * by libpng, in addition critical chunks must either be processed by the
+ * callback or saved.
+ *
+ * The IHDR and IEND chunks must not be listed. Because this turns off the
+ * default handling for chunks that would otherwise be recognized the
+ * behavior of libpng transformations may well become incorrect!
+ *
+ * WRITE:
+ * When writing chunks the options only apply to the chunks specified by
+ * png_set_unknown_chunks (below), libpng will *always* write known chunks
+ * required by png_set_ calls and will always write the core critical chunks
+ * (as required for PLTE).
+ *
+ * Each chunk in the png_set_unknown_chunks list is looked up in the
+ * png_set_keep_unknown_chunks list to find the keep setting, this is then
+ * interpreted as follows:
+ *
+ * PNG_HANDLE_CHUNK_AS_DEFAULT:
+ * Write safe-to-copy chunks and write other chunks if the global
+ * default is set to _ALWAYS, otherwise don't write this chunk.
+ * PNG_HANDLE_CHUNK_NEVER:
+ * Do not write the chunk.
+ * PNG_HANDLE_CHUNK_IF_SAFE:
+ * Write the chunk if it is safe-to-copy, otherwise do not write it.
+ * PNG_HANDLE_CHUNK_ALWAYS:
+ * Write the chunk.
+ *
+ * Note that the default behavior is effectively the opposite of the read case -
+ * in read unknown chunks are not stored by default, in write they are written
+ * by default. Also the behavior of PNG_HANDLE_CHUNK_IF_SAFE is very different
+ * - on write the safe-to-copy bit is checked, on read the critical bit is
+ * checked and on read if the chunk is critical an error will be raised.
+ *
+ * num_chunks:
+ * ===========
+ * If num_chunks is positive, then the "keep" parameter specifies the manner
+ * for handling only those chunks appearing in the chunk_list array,
+ * otherwise the chunk list array is ignored.
+ *
+ * If num_chunks is 0 the "keep" parameter specifies the default behavior for
+ * unknown chunks, as described above.
+ *
+ * If num_chunks is negative, then the "keep" parameter specifies the manner
+ * for handling all unknown chunks plus all chunks recognized by libpng
+ * except for the IHDR, PLTE, tRNS, IDAT, and IEND chunks (which continue to
+ * be processed by libpng.
+ */
+PNG_EXPORT(172, void, png_set_keep_unknown_chunks, (png_structrp png_ptr,
+ int keep, png_const_bytep chunk_list, int num_chunks));
+
+/* The "keep" PNG_HANDLE_CHUNK_ parameter for the specified chunk is returned;
+ * the result is therefore true (non-zero) if special handling is required,
+ * false for the default handling.
+ */
+PNG_EXPORT(173, int, png_handle_as_unknown, (png_const_structrp png_ptr,
+ png_const_bytep chunk_name));
+#endif
+
+#ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED
+PNG_EXPORT(174, void, png_set_unknown_chunks, (png_const_structrp png_ptr,
+ png_inforp info_ptr, png_const_unknown_chunkp unknowns,
+ int num_unknowns));
+ /* NOTE: prior to 1.6.0 this routine set the 'location' field of the added
+ * unknowns to the location currently stored in the png_struct. This is
+ * invariably the wrong value on write. To fix this call the following API
+ * for each chunk in the list with the correct location. If you know your
+ * code won't be compiled on earlier versions you can rely on
+ * png_set_unknown_chunks(write-ptr, png_get_unknown_chunks(read-ptr)) doing
+ * the correct thing.
+ */
+
+PNG_EXPORT(175, void, png_set_unknown_chunk_location,
+ (png_const_structrp png_ptr, png_inforp info_ptr, int chunk, int location));
+
+PNG_EXPORT(176, int, png_get_unknown_chunks, (png_const_structrp png_ptr,
+ png_inforp info_ptr, png_unknown_chunkpp entries));
+#endif
+
+/* Png_free_data() will turn off the "valid" flag for anything it frees.
+ * If you need to turn it off for a chunk that your application has freed,
+ * you can use png_set_invalid(png_ptr, info_ptr, PNG_INFO_CHNK);
+ */
+PNG_EXPORT(177, void, png_set_invalid, (png_const_structrp png_ptr,
+ png_inforp info_ptr, int mask));
+
+#ifdef PNG_INFO_IMAGE_SUPPORTED
+/* The "params" pointer is currently not used and is for future expansion. */
+#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
+PNG_EXPORT(178, void, png_read_png, (png_structrp png_ptr, png_inforp info_ptr,
+ int transforms, png_voidp params));
+#endif
+#ifdef PNG_WRITE_SUPPORTED
+PNG_EXPORT(179, void, png_write_png, (png_structrp png_ptr, png_inforp info_ptr,
+ int transforms, png_voidp params));
+#endif
+#endif
+
+PNG_EXPORT(180, png_const_charp, png_get_copyright,
+ (png_const_structrp png_ptr));
+PNG_EXPORT(181, png_const_charp, png_get_header_ver,
+ (png_const_structrp png_ptr));
+PNG_EXPORT(182, png_const_charp, png_get_header_version,
+ (png_const_structrp png_ptr));
+PNG_EXPORT(183, png_const_charp, png_get_libpng_ver,
+ (png_const_structrp png_ptr));
+
+#ifdef PNG_MNG_FEATURES_SUPPORTED
+PNG_EXPORT(184, png_uint_32, png_permit_mng_features, (png_structrp png_ptr,
+ png_uint_32 mng_features_permitted));
+#endif
+
+/* For use in png_set_keep_unknown, added to version 1.2.6 */
+#define PNG_HANDLE_CHUNK_AS_DEFAULT 0
+#define PNG_HANDLE_CHUNK_NEVER 1
+#define PNG_HANDLE_CHUNK_IF_SAFE 2
+#define PNG_HANDLE_CHUNK_ALWAYS 3
+#define PNG_HANDLE_CHUNK_LAST 4
+
+/* Strip the prepended error numbers ("#nnn ") from error and warning
+ * messages before passing them to the error or warning handler.
+ */
+#ifdef PNG_ERROR_NUMBERS_SUPPORTED
+PNG_EXPORT(185, void, png_set_strip_error_numbers, (png_structrp png_ptr,
+ png_uint_32 strip_mode));
+#endif
+
+/* Added in libpng-1.2.6 */
+#ifdef PNG_SET_USER_LIMITS_SUPPORTED
+PNG_EXPORT(186, void, png_set_user_limits, (png_structrp png_ptr,
+ png_uint_32 user_width_max, png_uint_32 user_height_max));
+PNG_EXPORT(187, png_uint_32, png_get_user_width_max,
+ (png_const_structrp png_ptr));
+PNG_EXPORT(188, png_uint_32, png_get_user_height_max,
+ (png_const_structrp png_ptr));
+/* Added in libpng-1.4.0 */
+PNG_EXPORT(189, void, png_set_chunk_cache_max, (png_structrp png_ptr,
+ png_uint_32 user_chunk_cache_max));
+PNG_EXPORT(190, png_uint_32, png_get_chunk_cache_max,
+ (png_const_structrp png_ptr));
+/* Added in libpng-1.4.1 */
+PNG_EXPORT(191, void, png_set_chunk_malloc_max, (png_structrp png_ptr,
+ png_alloc_size_t user_chunk_cache_max));
+PNG_EXPORT(192, png_alloc_size_t, png_get_chunk_malloc_max,
+ (png_const_structrp png_ptr));
+#endif
+
+#if defined(PNG_INCH_CONVERSIONS_SUPPORTED)
+PNG_EXPORT(193, png_uint_32, png_get_pixels_per_inch,
+ (png_const_structrp png_ptr, png_const_inforp info_ptr));
+
+PNG_EXPORT(194, png_uint_32, png_get_x_pixels_per_inch,
+ (png_const_structrp png_ptr, png_const_inforp info_ptr));
+
+PNG_EXPORT(195, png_uint_32, png_get_y_pixels_per_inch,
+ (png_const_structrp png_ptr, png_const_inforp info_ptr));
+
+PNG_FP_EXPORT(196, float, png_get_x_offset_inches,
+ (png_const_structrp png_ptr, png_const_inforp info_ptr))
+#ifdef PNG_FIXED_POINT_SUPPORTED /* otherwise not implemented. */
+PNG_FIXED_EXPORT(211, png_fixed_point, png_get_x_offset_inches_fixed,
+ (png_const_structrp png_ptr, png_const_inforp info_ptr))
+#endif
+
+PNG_FP_EXPORT(197, float, png_get_y_offset_inches, (png_const_structrp png_ptr,
+ png_const_inforp info_ptr))
+#ifdef PNG_FIXED_POINT_SUPPORTED /* otherwise not implemented. */
+PNG_FIXED_EXPORT(212, png_fixed_point, png_get_y_offset_inches_fixed,
+ (png_const_structrp png_ptr, png_const_inforp info_ptr))
+#endif
+
+# ifdef PNG_pHYs_SUPPORTED
+PNG_EXPORT(198, png_uint_32, png_get_pHYs_dpi, (png_const_structrp png_ptr,
+ png_const_inforp info_ptr, png_uint_32 *res_x, png_uint_32 *res_y,
+ int *unit_type));
+# endif /* pHYs */
+#endif /* INCH_CONVERSIONS */
+
+/* Added in libpng-1.4.0 */
+#ifdef PNG_IO_STATE_SUPPORTED
+PNG_EXPORT(199, png_uint_32, png_get_io_state, (png_const_structrp png_ptr));
+
+/* Removed from libpng 1.6; use png_get_io_chunk_type. */
+PNG_REMOVED(200, png_const_bytep, png_get_io_chunk_name, (png_structrp png_ptr),
+ PNG_DEPRECATED)
+
+PNG_EXPORT(216, png_uint_32, png_get_io_chunk_type,
+ (png_const_structrp png_ptr));
+
+/* The flags returned by png_get_io_state() are the following: */
+# define PNG_IO_NONE 0x0000 /* no I/O at this moment */
+# define PNG_IO_READING 0x0001 /* currently reading */
+# define PNG_IO_WRITING 0x0002 /* currently writing */
+# define PNG_IO_SIGNATURE 0x0010 /* currently at the file signature */
+# define PNG_IO_CHUNK_HDR 0x0020 /* currently at the chunk header */
+# define PNG_IO_CHUNK_DATA 0x0040 /* currently at the chunk data */
+# define PNG_IO_CHUNK_CRC 0x0080 /* currently at the chunk crc */
+# define PNG_IO_MASK_OP 0x000f /* current operation: reading/writing */
+# define PNG_IO_MASK_LOC 0x00f0 /* current location: sig/hdr/data/crc */
+#endif /* IO_STATE */
+
+/* Interlace support. The following macros are always defined so that if
+ * libpng interlace handling is turned off the macros may be used to handle
+ * interlaced images within the application.
+ */
+#define PNG_INTERLACE_ADAM7_PASSES 7
+
+/* Two macros to return the first row and first column of the original,
+ * full, image which appears in a given pass. 'pass' is in the range 0
+ * to 6 and the result is in the range 0 to 7.
+ */
+#define PNG_PASS_START_ROW(pass) (((1&~(pass))<<(3-((pass)>>1)))&7)
+#define PNG_PASS_START_COL(pass) (((1& (pass))<<(3-(((pass)+1)>>1)))&7)
+
+/* A macro to return the offset between pixels in the output row for a pair of
+ * pixels in the input - effectively the inverse of the 'COL_SHIFT' macro that
+ * follows. Note that ROW_OFFSET is the offset from one row to the next whereas
+ * COL_OFFSET is from one column to the next, within a row.
+ */
+#define PNG_PASS_ROW_OFFSET(pass) ((pass)>2?(8>>(((pass)-1)>>1)):8)
+#define PNG_PASS_COL_OFFSET(pass) (1<<((7-(pass))>>1))
+
+/* Two macros to help evaluate the number of rows or columns in each
+ * pass. This is expressed as a shift - effectively log2 of the number or
+ * rows or columns in each 8x8 tile of the original image.
+ */
+#define PNG_PASS_ROW_SHIFT(pass) ((pass)>2?(8-(pass))>>1:3)
+#define PNG_PASS_COL_SHIFT(pass) ((pass)>1?(7-(pass))>>1:3)
+
+/* Hence two macros to determine the number of rows or columns in a given
+ * pass of an image given its height or width. In fact these macros may
+ * return non-zero even though the sub-image is empty, because the other
+ * dimension may be empty for a small image.
+ */
+#define PNG_PASS_ROWS(height, pass) (((height)+(((1<<PNG_PASS_ROW_SHIFT(pass))\
+ -1)-PNG_PASS_START_ROW(pass)))>>PNG_PASS_ROW_SHIFT(pass))
+#define PNG_PASS_COLS(width, pass) (((width)+(((1<<PNG_PASS_COL_SHIFT(pass))\
+ -1)-PNG_PASS_START_COL(pass)))>>PNG_PASS_COL_SHIFT(pass))
+
+/* For the reader row callbacks (both progressive and sequential) it is
+ * necessary to find the row in the output image given a row in an interlaced
+ * image, so two more macros:
+ */
+#define PNG_ROW_FROM_PASS_ROW(y_in, pass) \
+ (((y_in)<<PNG_PASS_ROW_SHIFT(pass))+PNG_PASS_START_ROW(pass))
+#define PNG_COL_FROM_PASS_COL(x_in, pass) \
+ (((x_in)<<PNG_PASS_COL_SHIFT(pass))+PNG_PASS_START_COL(pass))
+
+/* Two macros which return a boolean (0 or 1) saying whether the given row
+ * or column is in a particular pass. These use a common utility macro that
+ * returns a mask for a given pass - the offset 'off' selects the row or
+ * column version. The mask has the appropriate bit set for each column in
+ * the tile.
+ */
+#define PNG_PASS_MASK(pass,off) ( \
+ ((0x110145AF>>(((7-(off))-(pass))<<2)) & 0xF) | \
+ ((0x01145AF0>>(((7-(off))-(pass))<<2)) & 0xF0))
+
+#define PNG_ROW_IN_INTERLACE_PASS(y, pass) \
+ ((PNG_PASS_MASK(pass,0) >> ((y)&7)) & 1)
+#define PNG_COL_IN_INTERLACE_PASS(x, pass) \
+ ((PNG_PASS_MASK(pass,1) >> ((x)&7)) & 1)
+
+#ifdef PNG_READ_COMPOSITE_NODIV_SUPPORTED
+/* With these routines we avoid an integer divide, which will be slower on
+ * most machines. However, it does take more operations than the corresponding
+ * divide method, so it may be slower on a few RISC systems. There are two
+ * shifts (by 8 or 16 bits) and an addition, versus a single integer divide.
+ *
+ * Note that the rounding factors are NOT supposed to be the same! 128 and
+ * 32768 are correct for the NODIV code; 127 and 32767 are correct for the
+ * standard method.
+ *
+ * [Optimized code by Greg Roelofs and Mark Adler...blame us for bugs. :-) ]
+ */
+
+ /* fg and bg should be in `gamma 1.0' space; alpha is the opacity */
+
+# define png_composite(composite, fg, alpha, bg) \
+ { png_uint_16 temp = (png_uint_16)((png_uint_16)(fg) \
+ * (png_uint_16)(alpha) \
+ + (png_uint_16)(bg)*(png_uint_16)(255 \
+ - (png_uint_16)(alpha)) + 128); \
+ (composite) = (png_byte)(((temp + (temp >> 8)) >> 8) & 0xff); }
+
+# define png_composite_16(composite, fg, alpha, bg) \
+ { png_uint_32 temp = (png_uint_32)((png_uint_32)(fg) \
+ * (png_uint_32)(alpha) \
+ + (png_uint_32)(bg)*(65535 \
+ - (png_uint_32)(alpha)) + 32768); \
+ (composite) = (png_uint_16)(0xffff & ((temp + (temp >> 16)) >> 16)); }
+
+#else /* Standard method using integer division */
+
+# define png_composite(composite, fg, alpha, bg) \
+ (composite) = \
+ (png_byte)(0xff & (((png_uint_16)(fg) * (png_uint_16)(alpha) + \
+ (png_uint_16)(bg) * (png_uint_16)(255 - (png_uint_16)(alpha)) + \
+ 127) / 255))
+
+# define png_composite_16(composite, fg, alpha, bg) \
+ (composite) = \
+ (png_uint_16)(0xffff & (((png_uint_32)(fg) * (png_uint_32)(alpha) + \
+ (png_uint_32)(bg)*(png_uint_32)(65535 - (png_uint_32)(alpha)) + \
+ 32767) / 65535))
+#endif /* READ_COMPOSITE_NODIV */
+
+#ifdef PNG_READ_INT_FUNCTIONS_SUPPORTED
+PNG_EXPORT(201, png_uint_32, png_get_uint_32, (png_const_bytep buf));
+PNG_EXPORT(202, png_uint_16, png_get_uint_16, (png_const_bytep buf));
+PNG_EXPORT(203, png_int_32, png_get_int_32, (png_const_bytep buf));
+#endif
+
+PNG_EXPORT(204, png_uint_32, png_get_uint_31, (png_const_structrp png_ptr,
+ png_const_bytep buf));
+/* No png_get_int_16 -- may be added if there's a real need for it. */
+
+/* Place a 32-bit number into a buffer in PNG byte order (big-endian). */
+#ifdef PNG_WRITE_INT_FUNCTIONS_SUPPORTED
+PNG_EXPORT(205, void, png_save_uint_32, (png_bytep buf, png_uint_32 i));
+#endif
+#ifdef PNG_SAVE_INT_32_SUPPORTED
+PNG_EXPORT(206, void, png_save_int_32, (png_bytep buf, png_int_32 i));
+#endif
+
+/* Place a 16-bit number into a buffer in PNG byte order.
+ * The parameter is declared unsigned int, not png_uint_16,
+ * just to avoid potential problems on pre-ANSI C compilers.
+ */
+#ifdef PNG_WRITE_INT_FUNCTIONS_SUPPORTED
+PNG_EXPORT(207, void, png_save_uint_16, (png_bytep buf, unsigned int i));
+/* No png_save_int_16 -- may be added if there's a real need for it. */
+#endif
+
+#ifdef PNG_USE_READ_MACROS
+/* Inline macros to do direct reads of bytes from the input buffer.
+ * The png_get_int_32() routine assumes we are using two's complement
+ * format for negative values, which is almost certainly true.
+ */
+# define PNG_get_uint_32(buf) \
+ (((png_uint_32)(*(buf)) << 24) + \
+ ((png_uint_32)(*((buf) + 1)) << 16) + \
+ ((png_uint_32)(*((buf) + 2)) << 8) + \
+ ((png_uint_32)(*((buf) + 3))))
+
+ /* From libpng-1.4.0 until 1.4.4, the png_get_uint_16 macro (but not the
+ * function) incorrectly returned a value of type png_uint_32.
+ */
+# define PNG_get_uint_16(buf) \
+ ((png_uint_16) \
+ (((unsigned int)(*(buf)) << 8) + \
+ ((unsigned int)(*((buf) + 1)))))
+
+# define PNG_get_int_32(buf) \
+ ((png_int_32)((*(buf) & 0x80) \
+ ? -((png_int_32)((png_get_uint_32(buf) ^ 0xffffffffL) + 1)) \
+ : (png_int_32)png_get_uint_32(buf)))
+
+ /* If PNG_PREFIX is defined the same thing as below happens in pnglibconf.h,
+ * but defining a macro name prefixed with PNG_PREFIX.
+ */
+# ifndef PNG_PREFIX
+# define png_get_uint_32(buf) PNG_get_uint_32(buf)
+# define png_get_uint_16(buf) PNG_get_uint_16(buf)
+# define png_get_int_32(buf) PNG_get_int_32(buf)
+# endif
+#else
+# ifdef PNG_PREFIX
+ /* No macros; revert to the (redefined) function */
+# define PNG_get_uint_32 (png_get_uint_32)
+# define PNG_get_uint_16 (png_get_uint_16)
+# define PNG_get_int_32 (png_get_int_32)
+# endif
+#endif
+
+#if defined(PNG_SIMPLIFIED_READ_SUPPORTED) || \
+ defined(PNG_SIMPLIFIED_WRITE_SUPPORTED)
+/*******************************************************************************
+ * SIMPLIFIED API
+ *******************************************************************************
+ *
+ * Please read the documentation in libpng-manual.txt (TODO: write said
+ * documentation) if you don't understand what follows.
+ *
+ * The simplified API hides the details of both libpng and the PNG file format
+ * itself. It allows PNG files to be read into a very limited number of
+ * in-memory bitmap formats or to be written from the same formats. If these
+ * formats do not accomodate your needs then you can, and should, use the more
+ * sophisticated APIs above - these support a wide variety of in-memory formats
+ * and a wide variety of sophisticated transformations to those formats as well
+ * as a wide variety of APIs to manipulate ancillary information.
+ *
+ * To read a PNG file using the simplified API:
+ *
+ * 1) Declare a 'png_image' structure (see below) on the stack and set the
+ * version field to PNG_IMAGE_VERSION.
+ * 2) Call the appropriate png_image_begin_read... function.
+ * 3) Set the png_image 'format' member to the required sample format.
+ * 4) Allocate a buffer for the image and, if required, the color-map.
+ * 5) Call png_image_finish_read to read the image and, if required, the
+ * color-map into your buffers.
+ *
+ * There are no restrictions on the format of the PNG input itself; all valid
+ * color types, bit depths, and interlace methods are acceptable, and the
+ * input image is transformed as necessary to the requested in-memory format
+ * during the png_image_finish_read() step. The only caveat is that if you
+ * request a color-mapped image from a PNG that is full-color or makes
+ * complex use of an alpha channel the transformation is extremely lossy and the
+ * result may look terrible.
+ *
+ * To write a PNG file using the simplified API:
+ *
+ * 1) Declare a 'png_image' structure on the stack and memset() it to all zero.
+ * 2) Initialize the members of the structure that describe the image, setting
+ * the 'format' member to the format of the image samples.
+ * 3) Call the appropriate png_image_write... function with a pointer to the
+ * image and, if necessary, the color-map to write the PNG data.
+ *
+ * png_image is a structure that describes the in-memory format of an image
+ * when it is being read or defines the in-memory format of an image that you
+ * need to write:
+ */
+#define PNG_IMAGE_VERSION 1
+
+typedef struct png_control *png_controlp;
+typedef struct
+{
+ png_controlp opaque; /* Initialize to NULL, free with png_image_free */
+ png_uint_32 version; /* Set to PNG_IMAGE_VERSION */
+ png_uint_32 width; /* Image width in pixels (columns) */
+ png_uint_32 height; /* Image height in pixels (rows) */
+ png_uint_32 format; /* Image format as defined below */
+ png_uint_32 flags; /* A bit mask containing informational flags */
+ png_uint_32 colormap_entries;
+ /* Number of entries in the color-map */
+
+ /* In the event of an error or warning the following field will be set to a
+ * non-zero value and the 'message' field will contain a '\0' terminated
+ * string with the libpng error or warning message. If both warnings and
+ * an error were encountered, only the error is recorded. If there
+ * are multiple warnings, only the first one is recorded.
+ *
+ * The upper 30 bits of this value are reserved, the low two bits contain
+ * a value as follows:
+ */
+# define PNG_IMAGE_WARNING 1
+# define PNG_IMAGE_ERROR 2
+ /*
+ * The result is a two-bit code such that a value more than 1 indicates
+ * a failure in the API just called:
+ *
+ * 0 - no warning or error
+ * 1 - warning
+ * 2 - error
+ * 3 - error preceded by warning
+ */
+# define PNG_IMAGE_FAILED(png_cntrl) ((((png_cntrl).warning_or_error)&0x03)>1)
+
+ png_uint_32 warning_or_error;
+
+ char message[64];
+} png_image, *png_imagep;
+
+/* The samples of the image have one to four channels whose components have
+ * original values in the range 0 to 1.0:
+ *
+ * 1: A single gray or luminance channel (G).
+ * 2: A gray/luminance channel and an alpha channel (GA).
+ * 3: Three red, green, blue color channels (RGB).
+ * 4: Three color channels and an alpha channel (RGBA).
+ *
+ * The components are encoded in one of two ways:
+ *
+ * a) As a small integer, value 0..255, contained in a single byte. For the
+ * alpha channel the original value is simply value/255. For the color or
+ * luminance channels the value is encoded according to the sRGB specification
+ * and matches the 8-bit format expected by typical display devices.
+ *
+ * The color/gray channels are not scaled (pre-multiplied) by the alpha
+ * channel and are suitable for passing to color management software.
+ *
+ * b) As a value in the range 0..65535, contained in a 2-byte integer. All
+ * channels can be converted to the original value by dividing by 65535; all
+ * channels are linear. Color channels use the RGB encoding (RGB end-points) of
+ * the sRGB specification. This encoding is identified by the
+ * PNG_FORMAT_FLAG_LINEAR flag below.
+ *
+ * When the simplified API needs to convert between sRGB and linear colorspaces,
+ * the actual sRGB transfer curve defined in the sRGB specification (see the
+ * article at http://en.wikipedia.org/wiki/SRGB) is used, not the gamma=1/2.2
+ * approximation used elsewhere in libpng.
+ *
+ * When an alpha channel is present it is expected to denote pixel coverage
+ * of the color or luminance channels and is returned as an associated alpha
+ * channel: the color/gray channels are scaled (pre-multiplied) by the alpha
+ * value.
+ *
+ * The samples are either contained directly in the image data, between 1 and 8
+ * bytes per pixel according to the encoding, or are held in a color-map indexed
+ * by bytes in the image data. In the case of a color-map the color-map entries
+ * are individual samples, encoded as above, and the image data has one byte per
+ * pixel to select the relevant sample from the color-map.
+ */
+
+/* PNG_FORMAT_*
+ *
+ * #defines to be used in png_image::format. Each #define identifies a
+ * particular layout of sample data and, if present, alpha values. There are
+ * separate defines for each of the two component encodings.
+ *
+ * A format is built up using single bit flag values. All combinations are
+ * valid. Formats can be built up from the flag values or you can use one of
+ * the predefined values below. When testing formats always use the FORMAT_FLAG
+ * macros to test for individual features - future versions of the library may
+ * add new flags.
+ *
+ * When reading or writing color-mapped images the format should be set to the
+ * format of the entries in the color-map then png_image_{read,write}_colormap
+ * called to read or write the color-map and set the format correctly for the
+ * image data. Do not set the PNG_FORMAT_FLAG_COLORMAP bit directly!
+ *
+ * NOTE: libpng can be built with particular features disabled, if you see
+ * compiler errors because the definition of one of the following flags has been
+ * compiled out it is because libpng does not have the required support. It is
+ * possible, however, for the libpng configuration to enable the format on just
+ * read or just write; in that case you may see an error at run time. You can
+ * guard against this by checking for the definition of the appropriate
+ * "_SUPPORTED" macro, one of:
+ *
+ * PNG_SIMPLIFIED_{READ,WRITE}_{BGR,AFIRST}_SUPPORTED
+ */
+#define PNG_FORMAT_FLAG_ALPHA 0x01U /* format with an alpha channel */
+#define PNG_FORMAT_FLAG_COLOR 0x02U /* color format: otherwise grayscale */
+#define PNG_FORMAT_FLAG_LINEAR 0x04U /* 2 byte channels else 1 byte */
+#define PNG_FORMAT_FLAG_COLORMAP 0x08U /* image data is color-mapped */
+
+#ifdef PNG_FORMAT_BGR_SUPPORTED
+# define PNG_FORMAT_FLAG_BGR 0x10U /* BGR colors, else order is RGB */
+#endif
+
+#ifdef PNG_FORMAT_AFIRST_SUPPORTED
+# define PNG_FORMAT_FLAG_AFIRST 0x20U /* alpha channel comes first */
+#endif
+
+/* Commonly used formats have predefined macros.
+ *
+ * First the single byte (sRGB) formats:
+ */
+#define PNG_FORMAT_GRAY 0
+#define PNG_FORMAT_GA PNG_FORMAT_FLAG_ALPHA
+#define PNG_FORMAT_AG (PNG_FORMAT_GA|PNG_FORMAT_FLAG_AFIRST)
+#define PNG_FORMAT_RGB PNG_FORMAT_FLAG_COLOR
+#define PNG_FORMAT_BGR (PNG_FORMAT_FLAG_COLOR|PNG_FORMAT_FLAG_BGR)
+#define PNG_FORMAT_RGBA (PNG_FORMAT_RGB|PNG_FORMAT_FLAG_ALPHA)
+#define PNG_FORMAT_ARGB (PNG_FORMAT_RGBA|PNG_FORMAT_FLAG_AFIRST)
+#define PNG_FORMAT_BGRA (PNG_FORMAT_BGR|PNG_FORMAT_FLAG_ALPHA)
+#define PNG_FORMAT_ABGR (PNG_FORMAT_BGRA|PNG_FORMAT_FLAG_AFIRST)
+
+/* Then the linear 2-byte formats. When naming these "Y" is used to
+ * indicate a luminance (gray) channel.
+ */
+#define PNG_FORMAT_LINEAR_Y PNG_FORMAT_FLAG_LINEAR
+#define PNG_FORMAT_LINEAR_Y_ALPHA (PNG_FORMAT_FLAG_LINEAR|PNG_FORMAT_FLAG_ALPHA)
+#define PNG_FORMAT_LINEAR_RGB (PNG_FORMAT_FLAG_LINEAR|PNG_FORMAT_FLAG_COLOR)
+#define PNG_FORMAT_LINEAR_RGB_ALPHA \
+ (PNG_FORMAT_FLAG_LINEAR|PNG_FORMAT_FLAG_COLOR|PNG_FORMAT_FLAG_ALPHA)
+
+/* With color-mapped formats the image data is one byte for each pixel, the byte
+ * is an index into the color-map which is formatted as above. To obtain a
+ * color-mapped format it is sufficient just to add the PNG_FOMAT_FLAG_COLORMAP
+ * to one of the above definitions, or you can use one of the definitions below.
+ */
+#define PNG_FORMAT_RGB_COLORMAP (PNG_FORMAT_RGB|PNG_FORMAT_FLAG_COLORMAP)
+#define PNG_FORMAT_BGR_COLORMAP (PNG_FORMAT_BGR|PNG_FORMAT_FLAG_COLORMAP)
+#define PNG_FORMAT_RGBA_COLORMAP (PNG_FORMAT_RGBA|PNG_FORMAT_FLAG_COLORMAP)
+#define PNG_FORMAT_ARGB_COLORMAP (PNG_FORMAT_ARGB|PNG_FORMAT_FLAG_COLORMAP)
+#define PNG_FORMAT_BGRA_COLORMAP (PNG_FORMAT_BGRA|PNG_FORMAT_FLAG_COLORMAP)
+#define PNG_FORMAT_ABGR_COLORMAP (PNG_FORMAT_ABGR|PNG_FORMAT_FLAG_COLORMAP)
+
+/* PNG_IMAGE macros
+ *
+ * These are convenience macros to derive information from a png_image
+ * structure. The PNG_IMAGE_SAMPLE_ macros return values appropriate to the
+ * actual image sample values - either the entries in the color-map or the
+ * pixels in the image. The PNG_IMAGE_PIXEL_ macros return corresponding values
+ * for the pixels and will always return 1 for color-mapped formats. The
+ * remaining macros return information about the rows in the image and the
+ * complete image.
+ *
+ * NOTE: All the macros that take a png_image::format parameter are compile time
+ * constants if the format parameter is, itself, a constant. Therefore these
+ * macros can be used in array declarations and case labels where required.
+ * Similarly the macros are also pre-processor constants (sizeof is not used) so
+ * they can be used in #if tests.
+ *
+ * First the information about the samples.
+ */
+#define PNG_IMAGE_SAMPLE_CHANNELS(fmt)\
+ (((fmt)&(PNG_FORMAT_FLAG_COLOR|PNG_FORMAT_FLAG_ALPHA))+1)
+ /* Return the total number of channels in a given format: 1..4 */
+
+#define PNG_IMAGE_SAMPLE_COMPONENT_SIZE(fmt)\
+ ((((fmt) & PNG_FORMAT_FLAG_LINEAR) >> 2)+1)
+ /* Return the size in bytes of a single component of a pixel or color-map
+ * entry (as appropriate) in the image: 1 or 2.
+ */
+
+#define PNG_IMAGE_SAMPLE_SIZE(fmt)\
+ (PNG_IMAGE_SAMPLE_CHANNELS(fmt) * PNG_IMAGE_SAMPLE_COMPONENT_SIZE(fmt))
+ /* This is the size of the sample data for one sample. If the image is
+ * color-mapped it is the size of one color-map entry (and image pixels are
+ * one byte in size), otherwise it is the size of one image pixel.
+ */
+
+#define PNG_IMAGE_MAXIMUM_COLORMAP_COMPONENTS(fmt)\
+ (PNG_IMAGE_SAMPLE_CHANNELS(fmt) * 256)
+ /* The maximum size of the color-map required by the format expressed in a
+ * count of components. This can be used to compile-time allocate a
+ * color-map:
+ *
+ * png_uint_16 colormap[PNG_IMAGE_MAXIMUM_COLORMAP_COMPONENTS(linear_fmt)];
+ *
+ * png_byte colormap[PNG_IMAGE_MAXIMUM_COLORMAP_COMPONENTS(sRGB_fmt)];
+ *
+ * Alternatively use the PNG_IMAGE_COLORMAP_SIZE macro below to use the
+ * information from one of the png_image_begin_read_ APIs and dynamically
+ * allocate the required memory.
+ */
+
+/* Corresponding information about the pixels */
+#define PNG_IMAGE_PIXEL_(test,fmt)\
+ (((fmt)&PNG_FORMAT_FLAG_COLORMAP)?1:test(fmt))
+
+#define PNG_IMAGE_PIXEL_CHANNELS(fmt)\
+ PNG_IMAGE_PIXEL_(PNG_IMAGE_SAMPLE_CHANNELS,fmt)
+ /* The number of separate channels (components) in a pixel; 1 for a
+ * color-mapped image.
+ */
+
+#define PNG_IMAGE_PIXEL_COMPONENT_SIZE(fmt)\
+ PNG_IMAGE_PIXEL_(PNG_IMAGE_SAMPLE_COMPONENT_SIZE,fmt)
+ /* The size, in bytes, of each component in a pixel; 1 for a color-mapped
+ * image.
+ */
+
+#define PNG_IMAGE_PIXEL_SIZE(fmt) PNG_IMAGE_PIXEL_(PNG_IMAGE_SAMPLE_SIZE,fmt)
+ /* The size, in bytes, of a complete pixel; 1 for a color-mapped image. */
+
+/* Information about the whole row, or whole image */
+#define PNG_IMAGE_ROW_STRIDE(image)\
+ (PNG_IMAGE_PIXEL_CHANNELS((image).format) * (image).width)
+ /* Return the total number of components in a single row of the image; this
+ * is the minimum 'row stride', the minimum count of components between each
+ * row. For a color-mapped image this is the minimum number of bytes in a
+ * row.
+ */
+
+#define PNG_IMAGE_BUFFER_SIZE(image, row_stride)\
+ (PNG_IMAGE_PIXEL_COMPONENT_SIZE((image).format)*(image).height*(row_stride))
+ /* Return the size, in bytes, of an image buffer given a png_image and a row
+ * stride - the number of components to leave space for in each row.
+ */
+
+#define PNG_IMAGE_SIZE(image)\
+ PNG_IMAGE_BUFFER_SIZE(image, PNG_IMAGE_ROW_STRIDE(image))
+ /* Return the size, in bytes, of the image in memory given just a png_image;
+ * the row stride is the minimum stride required for the image.
+ */
+
+#define PNG_IMAGE_COLORMAP_SIZE(image)\
+ (PNG_IMAGE_SAMPLE_SIZE((image).format) * (image).colormap_entries)
+ /* Return the size, in bytes, of the color-map of this image. If the image
+ * format is not a color-map format this will return a size sufficient for
+ * 256 entries in the given format; check PNG_FORMAT_FLAG_COLORMAP if
+ * you don't want to allocate a color-map in this case.
+ */
+
+/* PNG_IMAGE_FLAG_*
+ *
+ * Flags containing additional information about the image are held in the
+ * 'flags' field of png_image.
+ */
+#define PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB 0x01
+ /* This indicates the the RGB values of the in-memory bitmap do not
+ * correspond to the red, green and blue end-points defined by sRGB.
+ */
+
+#define PNG_IMAGE_FLAG_FAST 0x02
+ /* On write emphasise speed over compression; the resultant PNG file will be
+ * larger but will be produced significantly faster, particular for large
+ * images. Do not use this option for images which will be distributed, only
+ * used it when producing intermediate files that will be read back in
+ * repeatedly. For a typical 24-bit image the option will double the read
+ * speed at the cost of increasing the image size by 25%, however for many
+ * more compressible images the PNG file can be 10 times larger with only a
+ * slight speed gain.
+ */
+
+#define PNG_IMAGE_FLAG_16BIT_sRGB 0x04
+ /* On read if the image is a 16-bit per component image and there is no gAMA
+ * or sRGB chunk assume that the components are sRGB encoded. Notice that
+ * images output by the simplified API always have gamma information; setting
+ * this flag only affects the interpretation of 16-bit images from an
+ * external source. It is recommended that the application expose this flag
+ * to the user; the user can normally easily recognize the difference between
+ * linear and sRGB encoding. This flag has no effect on write - the data
+ * passed to the write APIs must have the correct encoding (as defined
+ * above.)
+ *
+ * If the flag is not set (the default) input 16-bit per component data is
+ * assumed to be linear.
+ *
+ * NOTE: the flag can only be set after the png_image_begin_read_ call,
+ * because that call initializes the 'flags' field.
+ */
+
+#ifdef PNG_SIMPLIFIED_READ_SUPPORTED
+/* READ APIs
+ * ---------
+ *
+ * The png_image passed to the read APIs must have been initialized by setting
+ * the png_controlp field 'opaque' to NULL (or, safer, memset the whole thing.)
+ */
+#ifdef PNG_STDIO_SUPPORTED
+PNG_EXPORT(234, int, png_image_begin_read_from_file, (png_imagep image,
+ const char *file_name));
+ /* The named file is opened for read and the image header is filled in
+ * from the PNG header in the file.
+ */
+
+PNG_EXPORT(235, int, png_image_begin_read_from_stdio, (png_imagep image,
+ FILE* file));
+ /* The PNG header is read from the stdio FILE object. */
+#endif /* STDIO */
+
+PNG_EXPORT(236, int, png_image_begin_read_from_memory, (png_imagep image,
+ png_const_voidp memory, png_size_t size));
+ /* The PNG header is read from the given memory buffer. */
+
+PNG_EXPORT(237, int, png_image_finish_read, (png_imagep image,
+ png_const_colorp background, void *buffer, png_int_32 row_stride,
+ void *colormap));
+ /* Finish reading the image into the supplied buffer and clean up the
+ * png_image structure.
+ *
+ * row_stride is the step, in byte or 2-byte units as appropriate,
+ * between adjacent rows. A positive stride indicates that the top-most row
+ * is first in the buffer - the normal top-down arrangement. A negative
+ * stride indicates that the bottom-most row is first in the buffer.
+ *
+ * background need only be supplied if an alpha channel must be removed from
+ * a png_byte format and the removal is to be done by compositing on a solid
+ * color; otherwise it may be NULL and any composition will be done directly
+ * onto the buffer. The value is an sRGB color to use for the background,
+ * for grayscale output the green channel is used.
+ *
+ * background must be supplied when an alpha channel must be removed from a
+ * single byte color-mapped output format, in other words if:
+ *
+ * 1) The original format from png_image_begin_read_from_* had
+ * PNG_FORMAT_FLAG_ALPHA set.
+ * 2) The format set by the application does not.
+ * 3) The format set by the application has PNG_FORMAT_FLAG_COLORMAP set and
+ * PNG_FORMAT_FLAG_LINEAR *not* set.
+ *
+ * For linear output removing the alpha channel is always done by compositing
+ * on black and background is ignored.
+ *
+ * colormap must be supplied when PNG_FORMAT_FLAG_COLORMAP is set. It must
+ * be at least the size (in bytes) returned by PNG_IMAGE_COLORMAP_SIZE.
+ * image->colormap_entries will be updated to the actual number of entries
+ * written to the colormap; this may be less than the original value.
+ */
+
+PNG_EXPORT(238, void, png_image_free, (png_imagep image));
+ /* Free any data allocated by libpng in image->opaque, setting the pointer to
+ * NULL. May be called at any time after the structure is initialized.
+ */
+#endif /* SIMPLIFIED_READ */
+
+#ifdef PNG_SIMPLIFIED_WRITE_SUPPORTED
+#ifdef PNG_STDIO_SUPPORTED
+/* WRITE APIS
+ * ----------
+ * For write you must initialize a png_image structure to describe the image to
+ * be written. To do this use memset to set the whole structure to 0 then
+ * initialize fields describing your image.
+ *
+ * version: must be set to PNG_IMAGE_VERSION
+ * opaque: must be initialized to NULL
+ * width: image width in pixels
+ * height: image height in rows
+ * format: the format of the data (image and color-map) you wish to write
+ * flags: set to 0 unless one of the defined flags applies; set
+ * PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB for color format images where the RGB
+ * values do not correspond to the colors in sRGB.
+ * colormap_entries: set to the number of entries in the color-map (0 to 256)
+ */
+PNG_EXPORT(239, int, png_image_write_to_file, (png_imagep image,
+ const char *file, int convert_to_8bit, const void *buffer,
+ png_int_32 row_stride, const void *colormap));
+ /* Write the image to the named file. */
+
+PNG_EXPORT(240, int, png_image_write_to_stdio, (png_imagep image, FILE *file,
+ int convert_to_8_bit, const void *buffer, png_int_32 row_stride,
+ const void *colormap));
+ /* Write the image to the given (FILE*). */
+
+/* With both write APIs if image is in one of the linear formats with 16-bit
+ * data then setting convert_to_8_bit will cause the output to be an 8-bit PNG
+ * gamma encoded according to the sRGB specification, otherwise a 16-bit linear
+ * encoded PNG file is written.
+ *
+ * With color-mapped data formats the colormap parameter point to a color-map
+ * with at least image->colormap_entries encoded in the specified format. If
+ * the format is linear the written PNG color-map will be converted to sRGB
+ * regardless of the convert_to_8_bit flag.
+ *
+ * With all APIs row_stride is handled as in the read APIs - it is the spacing
+ * from one row to the next in component sized units (1 or 2 bytes) and if
+ * negative indicates a bottom-up row layout in the buffer.
+ *
+ * Note that the write API does not support interlacing or sub-8-bit pixels.
+ */
+#endif /* STDIO */
+#endif /* SIMPLIFIED_WRITE */
+/*******************************************************************************
+ * END OF SIMPLIFIED API
+ ******************************************************************************/
+#endif /* SIMPLIFIED_{READ|WRITE} */
+
+#ifdef PNG_CHECK_FOR_INVALID_INDEX_SUPPORTED
+PNG_EXPORT(242, void, png_set_check_for_invalid_index,
+ (png_structrp png_ptr, int allowed));
+# ifdef PNG_GET_PALETTE_MAX_SUPPORTED
+PNG_EXPORT(243, int, png_get_palette_max, (png_const_structp png_ptr,
+ png_const_infop info_ptr));
+# endif
+#endif /* CHECK_FOR_INVALID_INDEX */
+
+/*******************************************************************************
+ * IMPLEMENTATION OPTIONS
+ *******************************************************************************
+ *
+ * Support for arbitrary implementation-specific optimizations. The API allows
+ * particular options to be turned on or off. 'Option' is the number of the
+ * option and 'onoff' is 0 (off) or non-0 (on). The value returned is given
+ * by the PNG_OPTION_ defines below.
+ *
+ * HARDWARE: normally hardware capabilites, such as the Intel SSE instructions,
+ * are detected at run time, however sometimes it may be impossible
+ * to do this in user mode, in which case it is necessary to discover
+ * the capabilities in an OS specific way. Such capabilities are
+ * listed here when libpng has support for them and must be turned
+ * ON by the application if present.
+ *
+ * SOFTWARE: sometimes software optimizations actually result in performance
+ * decrease on some architectures or systems, or with some sets of
+ * PNG images. 'Software' options allow such optimizations to be
+ * selected at run time.
+ */
+#ifdef PNG_SET_OPTION_SUPPORTED
+#ifdef PNG_ARM_NEON_API_SUPPORTED
+# define PNG_ARM_NEON 0 /* HARDWARE: ARM Neon SIMD instructions supported */
+#endif
+#define PNG_MAXIMUM_INFLATE_WINDOW 2 /* SOFTWARE: force maximum window */
+#define PNG_SKIP_sRGB_CHECK_PROFILE 4 /* SOFTWARE: Check ICC profile for sRGB */
+#define PNG_OPTION_NEXT 6 /* Next option - numbers must be even */
+
+/* Return values: NOTE: there are four values and 'off' is *not* zero */
+#define PNG_OPTION_UNSET 0 /* Unset - defaults to off */
+#define PNG_OPTION_INVALID 1 /* Option number out of range */
+#define PNG_OPTION_OFF 2
+#define PNG_OPTION_ON 3
+
+PNG_EXPORT(244, int, png_set_option, (png_structrp png_ptr, int option,
+ int onoff));
+#endif /* SET_OPTION */
+
+/*******************************************************************************
+ * END OF HARDWARE AND SOFTWARE OPTIONS
+ ******************************************************************************/
+
+/* Maintainer: Put new public prototypes here ^, in libpng.3, in project
+ * defs, and in scripts/symbols.def.
+ */
+
+/* The last ordinal number (this is the *last* one already used; the next
+ * one to use is one more than this.)
+ */
+#ifdef PNG_EXPORT_LAST_ORDINAL
+ PNG_EXPORT_LAST_ORDINAL(244);
+#endif
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* PNG_VERSION_INFO_ONLY */
+/* Do not put anything past this line */
+#endif /* PNG_H */
--- /dev/null
+
+/* pngconf.h - machine configurable file for libpng
+ *
+ * libpng version 1.6.17, March 26, 2015
+ *
+ * Copyright (c) 1998-2015 Glenn Randers-Pehrson
+ * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
+ * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ *
+ * Any machine specific code is near the front of this file, so if you
+ * are configuring libpng for a machine, you may want to read the section
+ * starting here down to where it starts to typedef png_color, png_text,
+ * and png_info.
+ */
+
+#ifndef PNGCONF_H
+#define PNGCONF_H
+
+#ifndef PNG_BUILDING_SYMBOL_TABLE /* else includes may cause problems */
+
+/* From libpng 1.6.0 libpng requires an ANSI X3.159-1989 ("ISOC90") compliant C
+ * compiler for correct compilation. The following header files are required by
+ * the standard. If your compiler doesn't provide these header files, or they
+ * do not match the standard, you will need to provide/improve them.
+ */
+#include <limits.h>
+#include <stddef.h>
+
+/* Library header files. These header files are all defined by ISOC90; libpng
+ * expects conformant implementations, however, an ISOC90 conformant system need
+ * not provide these header files if the functionality cannot be implemented.
+ * In this case it will be necessary to disable the relevant parts of libpng in
+ * the build of pnglibconf.h.
+ *
+ * Prior to 1.6.0 string.h was included here; the API changes in 1.6.0 to not
+ * include this unnecessary header file.
+ */
+
+#ifdef PNG_STDIO_SUPPORTED
+ /* Required for the definition of FILE: */
+# include <stdio.h>
+#endif
+
+#ifdef PNG_SETJMP_SUPPORTED
+ /* Required for the definition of jmp_buf and the declaration of longjmp: */
+# include <setjmp.h>
+#endif
+
+#ifdef PNG_CONVERT_tIME_SUPPORTED
+ /* Required for struct tm: */
+# include <time.h>
+#endif
+
+#endif /* PNG_BUILDING_SYMBOL_TABLE */
+
+/* Prior to 1.6.0 it was possible to turn off 'const' in declarations using
+ * PNG_NO_CONST; this is no longer supported except for data declarations which
+ * apparently still cause problems in 2011 on some compilers.
+ */
+#define PNG_CONST const /* backward compatibility only */
+
+/* This controls optimization of the reading of 16 and 32 bit values
+ * from PNG files. It can be set on a per-app-file basis - it
+ * just changes whether a macro is used when the function is called.
+ * The library builder sets the default; if read functions are not
+ * built into the library the macro implementation is forced on.
+ */
+#ifndef PNG_READ_INT_FUNCTIONS_SUPPORTED
+# define PNG_USE_READ_MACROS
+#endif
+#if !defined(PNG_NO_USE_READ_MACROS) && !defined(PNG_USE_READ_MACROS)
+# if PNG_DEFAULT_READ_MACROS
+# define PNG_USE_READ_MACROS
+# endif
+#endif
+
+/* COMPILER SPECIFIC OPTIONS.
+ *
+ * These options are provided so that a variety of difficult compilers
+ * can be used. Some are fixed at build time (e.g. PNG_API_RULE
+ * below) but still have compiler specific implementations, others
+ * may be changed on a per-file basis when compiling against libpng.
+ */
+
+/* The PNGARG macro was used in versions of libpng prior to 1.6.0 to protect
+ * against legacy (pre ISOC90) compilers that did not understand function
+ * prototypes. It is not required for modern C compilers.
+ */
+#ifndef PNGARG
+# define PNGARG(arglist) arglist
+#endif
+
+/* Function calling conventions.
+ * =============================
+ * Normally it is not necessary to specify to the compiler how to call
+ * a function - it just does it - however on x86 systems derived from
+ * Microsoft and Borland C compilers ('IBM PC', 'DOS', 'Windows' systems
+ * and some others) there are multiple ways to call a function and the
+ * default can be changed on the compiler command line. For this reason
+ * libpng specifies the calling convention of every exported function and
+ * every function called via a user supplied function pointer. This is
+ * done in this file by defining the following macros:
+ *
+ * PNGAPI Calling convention for exported functions.
+ * PNGCBAPI Calling convention for user provided (callback) functions.
+ * PNGCAPI Calling convention used by the ANSI-C library (required
+ * for longjmp callbacks and sometimes used internally to
+ * specify the calling convention for zlib).
+ *
+ * These macros should never be overridden. If it is necessary to
+ * change calling convention in a private build this can be done
+ * by setting PNG_API_RULE (which defaults to 0) to one of the values
+ * below to select the correct 'API' variants.
+ *
+ * PNG_API_RULE=0 Use PNGCAPI - the 'C' calling convention - throughout.
+ * This is correct in every known environment.
+ * PNG_API_RULE=1 Use the operating system convention for PNGAPI and
+ * the 'C' calling convention (from PNGCAPI) for
+ * callbacks (PNGCBAPI). This is no longer required
+ * in any known environment - if it has to be used
+ * please post an explanation of the problem to the
+ * libpng mailing list.
+ *
+ * These cases only differ if the operating system does not use the C
+ * calling convention, at present this just means the above cases
+ * (x86 DOS/Windows sytems) and, even then, this does not apply to
+ * Cygwin running on those systems.
+ *
+ * Note that the value must be defined in pnglibconf.h so that what
+ * the application uses to call the library matches the conventions
+ * set when building the library.
+ */
+
+/* Symbol export
+ * =============
+ * When building a shared library it is almost always necessary to tell
+ * the compiler which symbols to export. The png.h macro 'PNG_EXPORT'
+ * is used to mark the symbols. On some systems these symbols can be
+ * extracted at link time and need no special processing by the compiler,
+ * on other systems the symbols are flagged by the compiler and just
+ * the declaration requires a special tag applied (unfortunately) in a
+ * compiler dependent way. Some systems can do either.
+ *
+ * A small number of older systems also require a symbol from a DLL to
+ * be flagged to the program that calls it. This is a problem because
+ * we do not know in the header file included by application code that
+ * the symbol will come from a shared library, as opposed to a statically
+ * linked one. For this reason the application must tell us by setting
+ * the magic flag PNG_USE_DLL to turn on the special processing before
+ * it includes png.h.
+ *
+ * Four additional macros are used to make this happen:
+ *
+ * PNG_IMPEXP The magic (if any) to cause a symbol to be exported from
+ * the build or imported if PNG_USE_DLL is set - compiler
+ * and system specific.
+ *
+ * PNG_EXPORT_TYPE(type) A macro that pre or appends PNG_IMPEXP to
+ * 'type', compiler specific.
+ *
+ * PNG_DLL_EXPORT Set to the magic to use during a libpng build to
+ * make a symbol exported from the DLL. Not used in the
+ * public header files; see pngpriv.h for how it is used
+ * in the libpng build.
+ *
+ * PNG_DLL_IMPORT Set to the magic to force the libpng symbols to come
+ * from a DLL - used to define PNG_IMPEXP when
+ * PNG_USE_DLL is set.
+ */
+
+/* System specific discovery.
+ * ==========================
+ * This code is used at build time to find PNG_IMPEXP, the API settings
+ * and PNG_EXPORT_TYPE(), it may also set a macro to indicate the DLL
+ * import processing is possible. On Windows systems it also sets
+ * compiler-specific macros to the values required to change the calling
+ * conventions of the various functions.
+ */
+#if defined(_Windows) || defined(_WINDOWS) || defined(WIN32) ||\
+ defined(_WIN32) || defined(__WIN32__) || defined(__CYGWIN__)
+ /* Windows system (DOS doesn't support DLLs). Includes builds under Cygwin or
+ * MinGW on any architecture currently supported by Windows. Also includes
+ * Watcom builds but these need special treatment because they are not
+ * compatible with GCC or Visual C because of different calling conventions.
+ */
+# if PNG_API_RULE == 2
+ /* If this line results in an error, either because __watcall is not
+ * understood or because of a redefine just below you cannot use *this*
+ * build of the library with the compiler you are using. *This* build was
+ * build using Watcom and applications must also be built using Watcom!
+ */
+# define PNGCAPI __watcall
+# endif
+
+# if defined(__GNUC__) || (defined (_MSC_VER) && (_MSC_VER >= 800)) || defined(__WINSCW__)
+# define PNGCAPI __cdecl
+# if PNG_API_RULE == 1
+ /* If this line results in an error __stdcall is not understood and
+ * PNG_API_RULE should not have been set to '1'.
+ */
+# define PNGAPI __stdcall
+# endif
+# else
+ /* An older compiler, or one not detected (erroneously) above,
+ * if necessary override on the command line to get the correct
+ * variants for the compiler.
+ */
+# ifndef PNGCAPI
+# define PNGCAPI _cdecl
+# endif
+# if PNG_API_RULE == 1 && !defined(PNGAPI)
+# define PNGAPI _stdcall
+# endif
+# endif /* compiler/api */
+
+ /* NOTE: PNGCBAPI always defaults to PNGCAPI. */
+
+# if defined(PNGAPI) && !defined(PNG_USER_PRIVATEBUILD)
+# error "PNG_USER_PRIVATEBUILD must be defined if PNGAPI is changed"
+# endif
+
+# if (defined(_MSC_VER) && _MSC_VER < 800) ||\
+ (defined(__BORLANDC__) && __BORLANDC__ < 0x500)
+ /* older Borland and MSC
+ * compilers used '__export' and required this to be after
+ * the type.
+ */
+# ifndef PNG_EXPORT_TYPE
+# define PNG_EXPORT_TYPE(type) type PNG_IMPEXP
+# endif
+# define PNG_DLL_EXPORT __export
+# else /* newer compiler */
+# define PNG_DLL_EXPORT __declspec(dllexport)
+# ifndef PNG_DLL_IMPORT
+# define PNG_DLL_IMPORT __declspec(dllimport)
+# endif
+# endif /* compiler */
+
+#else /* !Windows */
+# if (defined(__IBMC__) || defined(__IBMCPP__)) && defined(__OS2__)
+# define PNGAPI _System
+# else /* !Windows/x86 && !OS/2 */
+ /* Use the defaults, or define PNG*API on the command line (but
+ * this will have to be done for every compile!)
+ */
+# endif /* other system, !OS/2 */
+#endif /* !Windows/x86 */
+
+/* Now do all the defaulting . */
+#ifndef PNGCAPI
+# define PNGCAPI
+#endif
+#ifndef PNGCBAPI
+# define PNGCBAPI PNGCAPI
+#endif
+#ifndef PNGAPI
+# define PNGAPI PNGCAPI
+#endif
+
+/* PNG_IMPEXP may be set on the compilation system command line or (if not set)
+ * then in an internal header file when building the library, otherwise (when
+ * using the library) it is set here.
+ */
+#ifndef PNG_IMPEXP
+# if defined(PNG_USE_DLL) && defined(PNG_DLL_IMPORT)
+ /* This forces use of a DLL, disallowing static linking */
+# define PNG_IMPEXP PNG_DLL_IMPORT
+# endif
+
+# ifndef PNG_IMPEXP
+# define PNG_IMPEXP
+# endif
+#endif
+
+/* In 1.5.2 the definition of PNG_FUNCTION has been changed to always treat
+ * 'attributes' as a storage class - the attributes go at the start of the
+ * function definition, and attributes are always appended regardless of the
+ * compiler. This considerably simplifies these macros but may cause problems
+ * if any compilers both need function attributes and fail to handle them as
+ * a storage class (this is unlikely.)
+ */
+#ifndef PNG_FUNCTION
+# define PNG_FUNCTION(type, name, args, attributes) attributes type name args
+#endif
+
+#ifndef PNG_EXPORT_TYPE
+# define PNG_EXPORT_TYPE(type) PNG_IMPEXP type
+#endif
+
+ /* The ordinal value is only relevant when preprocessing png.h for symbol
+ * table entries, so we discard it here. See the .dfn files in the
+ * scripts directory.
+ */
+#ifndef PNG_EXPORTA
+
+# define PNG_EXPORTA(ordinal, type, name, args, attributes)\
+ PNG_FUNCTION(PNG_EXPORT_TYPE(type),(PNGAPI name),PNGARG(args), \
+ extern attributes)
+#endif
+
+/* ANSI-C (C90) does not permit a macro to be invoked with an empty argument,
+ * so make something non-empty to satisfy the requirement:
+ */
+#define PNG_EMPTY /*empty list*/
+
+#define PNG_EXPORT(ordinal, type, name, args)\
+ PNG_EXPORTA(ordinal, type, name, args, PNG_EMPTY)
+
+/* Use PNG_REMOVED to comment out a removed interface. */
+#ifndef PNG_REMOVED
+# define PNG_REMOVED(ordinal, type, name, args, attributes)
+#endif
+
+#ifndef PNG_CALLBACK
+# define PNG_CALLBACK(type, name, args) type (PNGCBAPI name) PNGARG(args)
+#endif
+
+/* Support for compiler specific function attributes. These are used
+ * so that where compiler support is available incorrect use of API
+ * functions in png.h will generate compiler warnings.
+ *
+ * Added at libpng-1.2.41.
+ */
+
+#ifndef PNG_NO_PEDANTIC_WARNINGS
+# ifndef PNG_PEDANTIC_WARNINGS_SUPPORTED
+# define PNG_PEDANTIC_WARNINGS_SUPPORTED
+# endif
+#endif
+
+#ifdef PNG_PEDANTIC_WARNINGS_SUPPORTED
+ /* Support for compiler specific function attributes. These are used
+ * so that where compiler support is available, incorrect use of API
+ * functions in png.h will generate compiler warnings. Added at libpng
+ * version 1.2.41. Disabling these removes the warnings but may also produce
+ * less efficient code.
+ */
+# if defined(__clang__) && defined(__has_attribute)
+ /* Clang defines both __clang__ and __GNUC__. Check __clang__ first. */
+# if !defined(PNG_USE_RESULT) && __has_attribute(__warn_unused_result__)
+# define PNG_USE_RESULT __attribute__((__warn_unused_result__))
+# endif
+# if !defined(PNG_NORETURN) && __has_attribute(__noreturn__)
+# define PNG_NORETURN __attribute__((__noreturn__))
+# endif
+# if !defined(PNG_ALLOCATED) && __has_attribute(__malloc__)
+# define PNG_ALLOCATED __attribute__((__malloc__))
+# endif
+# if !defined(PNG_DEPRECATED) && __has_attribute(__deprecated__)
+# define PNG_DEPRECATED __attribute__((__deprecated__))
+# endif
+# if !defined(PNG_PRIVATE)
+# ifdef __has_extension
+# if __has_extension(attribute_unavailable_with_message)
+# define PNG_PRIVATE __attribute__((__unavailable__(\
+ "This function is not exported by libpng.")))
+# endif
+# endif
+# endif
+# ifndef PNG_RESTRICT
+# define PNG_RESTRICT __restrict
+# endif
+
+# elif defined(__GNUC__)
+# ifndef PNG_USE_RESULT
+# define PNG_USE_RESULT __attribute__((__warn_unused_result__))
+# endif
+# ifndef PNG_NORETURN
+# define PNG_NORETURN __attribute__((__noreturn__))
+# endif
+# if __GNUC__ >= 3
+# ifndef PNG_ALLOCATED
+# define PNG_ALLOCATED __attribute__((__malloc__))
+# endif
+# ifndef PNG_DEPRECATED
+# define PNG_DEPRECATED __attribute__((__deprecated__))
+# endif
+# ifndef PNG_PRIVATE
+# if 0 /* Doesn't work so we use deprecated instead*/
+# define PNG_PRIVATE \
+ __attribute__((warning("This function is not exported by libpng.")))
+# else
+# define PNG_PRIVATE \
+ __attribute__((__deprecated__))
+# endif
+# endif
+# if ((__GNUC__ > 3) || !defined(__GNUC_MINOR__) || (__GNUC_MINOR__ >= 1))
+# ifndef PNG_RESTRICT
+# define PNG_RESTRICT __restrict
+# endif
+# endif /* __GNUC__.__GNUC_MINOR__ > 3.0 */
+# endif /* __GNUC__ >= 3 */
+
+# elif defined(_MSC_VER) && (_MSC_VER >= 1300)
+# ifndef PNG_USE_RESULT
+# define PNG_USE_RESULT /* not supported */
+# endif
+# ifndef PNG_NORETURN
+# define PNG_NORETURN __declspec(noreturn)
+# endif
+# ifndef PNG_ALLOCATED
+# if (_MSC_VER >= 1400)
+# define PNG_ALLOCATED __declspec(restrict)
+# endif
+# endif
+# ifndef PNG_DEPRECATED
+# define PNG_DEPRECATED __declspec(deprecated)
+# endif
+# ifndef PNG_PRIVATE
+# define PNG_PRIVATE __declspec(deprecated)
+# endif
+# ifndef PNG_RESTRICT
+# if (_MSC_VER >= 1400)
+# define PNG_RESTRICT __restrict
+# endif
+# endif
+
+# elif defined(__WATCOMC__)
+# ifndef PNG_RESTRICT
+# define PNG_RESTRICT __restrict
+# endif
+# endif
+#endif /* PNG_PEDANTIC_WARNINGS */
+
+#ifndef PNG_DEPRECATED
+# define PNG_DEPRECATED /* Use of this function is deprecated */
+#endif
+#ifndef PNG_USE_RESULT
+# define PNG_USE_RESULT /* The result of this function must be checked */
+#endif
+#ifndef PNG_NORETURN
+# define PNG_NORETURN /* This function does not return */
+#endif
+#ifndef PNG_ALLOCATED
+# define PNG_ALLOCATED /* The result of the function is new memory */
+#endif
+#ifndef PNG_PRIVATE
+# define PNG_PRIVATE /* This is a private libpng function */
+#endif
+#ifndef PNG_RESTRICT
+# define PNG_RESTRICT /* The C99 "restrict" feature */
+#endif
+
+#ifndef PNG_FP_EXPORT /* A floating point API. */
+# ifdef PNG_FLOATING_POINT_SUPPORTED
+# define PNG_FP_EXPORT(ordinal, type, name, args)\
+ PNG_EXPORT(ordinal, type, name, args);
+# else /* No floating point APIs */
+# define PNG_FP_EXPORT(ordinal, type, name, args)
+# endif
+#endif
+#ifndef PNG_FIXED_EXPORT /* A fixed point API. */
+# ifdef PNG_FIXED_POINT_SUPPORTED
+# define PNG_FIXED_EXPORT(ordinal, type, name, args)\
+ PNG_EXPORT(ordinal, type, name, args);
+# else /* No fixed point APIs */
+# define PNG_FIXED_EXPORT(ordinal, type, name, args)
+# endif
+#endif
+
+#ifndef PNG_BUILDING_SYMBOL_TABLE
+/* Some typedefs to get us started. These should be safe on most of the common
+ * platforms.
+ *
+ * png_uint_32 and png_int_32 may, currently, be larger than required to hold a
+ * 32-bit value however this is not normally advisable.
+ *
+ * png_uint_16 and png_int_16 should always be two bytes in size - this is
+ * verified at library build time.
+ *
+ * png_byte must always be one byte in size.
+ *
+ * The checks below use constants from limits.h, as defined by the ISOC90
+ * standard.
+ */
+#if CHAR_BIT == 8 && UCHAR_MAX == 255
+ typedef unsigned char png_byte;
+#else
+# error "libpng requires 8 bit bytes"
+#endif
+
+#if INT_MIN == -32768 && INT_MAX == 32767
+ typedef int png_int_16;
+#elif SHRT_MIN == -32768 && SHRT_MAX == 32767
+ typedef short png_int_16;
+#else
+# error "libpng requires a signed 16 bit type"
+#endif
+
+#if UINT_MAX == 65535
+ typedef unsigned int png_uint_16;
+#elif USHRT_MAX == 65535
+ typedef unsigned short png_uint_16;
+#else
+# error "libpng requires an unsigned 16 bit type"
+#endif
+
+#if INT_MIN < -2147483646 && INT_MAX > 2147483646
+ typedef int png_int_32;
+#elif LONG_MIN < -2147483646 && LONG_MAX > 2147483646
+ typedef long int png_int_32;
+#else
+# error "libpng requires a signed 32 bit (or more) type"
+#endif
+
+#if UINT_MAX > 4294967294
+ typedef unsigned int png_uint_32;
+#elif ULONG_MAX > 4294967294
+ typedef unsigned long int png_uint_32;
+#else
+# error "libpng requires an unsigned 32 bit (or more) type"
+#endif
+
+/* Prior to 1.6.0 it was possible to disable the use of size_t, 1.6.0, however,
+ * requires an ISOC90 compiler and relies on consistent behavior of sizeof.
+ */
+typedef size_t png_size_t;
+typedef ptrdiff_t png_ptrdiff_t;
+
+/* libpng needs to know the maximum value of 'size_t' and this controls the
+ * definition of png_alloc_size_t, below. This maximum value of size_t limits
+ * but does not control the maximum allocations the library makes - there is
+ * direct application control of this through png_set_user_limits().
+ */
+#ifndef PNG_SMALL_SIZE_T
+ /* Compiler specific tests for systems where size_t is known to be less than
+ * 32 bits (some of these systems may no longer work because of the lack of
+ * 'far' support; see above.)
+ */
+# if (defined(__TURBOC__) && !defined(__FLAT__)) ||\
+ (defined(_MSC_VER) && defined(MAXSEG_64K))
+# define PNG_SMALL_SIZE_T
+# endif
+#endif
+
+/* png_alloc_size_t is guaranteed to be no smaller than png_size_t, and no
+ * smaller than png_uint_32. Casts from png_size_t or png_uint_32 to
+ * png_alloc_size_t are not necessary; in fact, it is recommended not to use
+ * them at all so that the compiler can complain when something turns out to be
+ * problematic.
+ *
+ * Casts in the other direction (from png_alloc_size_t to png_size_t or
+ * png_uint_32) should be explicitly applied; however, we do not expect to
+ * encounter practical situations that require such conversions.
+ *
+ * PNG_SMALL_SIZE_T must be defined if the maximum value of size_t is less than
+ * 4294967295 - i.e. less than the maximum value of png_uint_32.
+ */
+#ifdef PNG_SMALL_SIZE_T
+ typedef png_uint_32 png_alloc_size_t;
+#else
+ typedef png_size_t png_alloc_size_t;
+#endif
+
+/* Prior to 1.6.0 libpng offered limited support for Microsoft C compiler
+ * implementations of Intel CPU specific support of user-mode segmented address
+ * spaces, where 16-bit pointers address more than 65536 bytes of memory using
+ * separate 'segment' registers. The implementation requires two different
+ * types of pointer (only one of which includes the segment value.)
+ *
+ * If required this support is available in version 1.2 of libpng and may be
+ * available in versions through 1.5, although the correctness of the code has
+ * not been verified recently.
+ */
+
+/* Typedef for floating-point numbers that are converted to fixed-point with a
+ * multiple of 100,000, e.g., gamma
+ */
+typedef png_int_32 png_fixed_point;
+
+/* Add typedefs for pointers */
+typedef void * png_voidp;
+typedef const void * png_const_voidp;
+typedef png_byte * png_bytep;
+typedef const png_byte * png_const_bytep;
+typedef png_uint_32 * png_uint_32p;
+typedef const png_uint_32 * png_const_uint_32p;
+typedef png_int_32 * png_int_32p;
+typedef const png_int_32 * png_const_int_32p;
+typedef png_uint_16 * png_uint_16p;
+typedef const png_uint_16 * png_const_uint_16p;
+typedef png_int_16 * png_int_16p;
+typedef const png_int_16 * png_const_int_16p;
+typedef char * png_charp;
+typedef const char * png_const_charp;
+typedef png_fixed_point * png_fixed_point_p;
+typedef const png_fixed_point * png_const_fixed_point_p;
+typedef png_size_t * png_size_tp;
+typedef const png_size_t * png_const_size_tp;
+
+#ifdef PNG_STDIO_SUPPORTED
+typedef FILE * png_FILE_p;
+#endif
+
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+typedef double * png_doublep;
+typedef const double * png_const_doublep;
+#endif
+
+/* Pointers to pointers; i.e. arrays */
+typedef png_byte * * png_bytepp;
+typedef png_uint_32 * * png_uint_32pp;
+typedef png_int_32 * * png_int_32pp;
+typedef png_uint_16 * * png_uint_16pp;
+typedef png_int_16 * * png_int_16pp;
+typedef const char * * png_const_charpp;
+typedef char * * png_charpp;
+typedef png_fixed_point * * png_fixed_point_pp;
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+typedef double * * png_doublepp;
+#endif
+
+/* Pointers to pointers to pointers; i.e., pointer to array */
+typedef char * * * png_charppp;
+
+#endif /* PNG_BUILDING_SYMBOL_TABLE */
+
+#endif /* PNGCONF_H */
--- /dev/null
+
+/* pngdebug.h - Debugging macros for libpng, also used in pngtest.c
+ *
+ * Last changed in libpng 1.6.8 [December 19, 2013]
+ * Copyright (c) 1998-2013 Glenn Randers-Pehrson
+ * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
+ * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ */
+
+/* Define PNG_DEBUG at compile time for debugging information. Higher
+ * numbers for PNG_DEBUG mean more debugging information. This has
+ * only been added since version 0.95 so it is not implemented throughout
+ * libpng yet, but more support will be added as needed.
+ *
+ * png_debug[1-2]?(level, message ,arg{0-2})
+ * Expands to a statement (either a simple expression or a compound
+ * do..while(0) statement) that outputs a message with parameter
+ * substitution if PNG_DEBUG is defined to 2 or more. If PNG_DEBUG
+ * is undefined, 0 or 1 every png_debug expands to a simple expression
+ * (actually ((void)0)).
+ *
+ * level: level of detail of message, starting at 0. A level 'n'
+ * message is preceded by 'n' 3-space indentations (not implemented
+ * on Microsoft compilers unless PNG_DEBUG_FILE is also
+ * defined, to allow debug DLL compilation with no standard IO).
+ * message: a printf(3) style text string. A trailing '\n' is added
+ * to the message.
+ * arg: 0 to 2 arguments for printf(3) style substitution in message.
+ */
+#ifndef PNGDEBUG_H
+#define PNGDEBUG_H
+/* These settings control the formatting of messages in png.c and pngerror.c */
+/* Moved to pngdebug.h at 1.5.0 */
+# ifndef PNG_LITERAL_SHARP
+# define PNG_LITERAL_SHARP 0x23
+# endif
+# ifndef PNG_LITERAL_LEFT_SQUARE_BRACKET
+# define PNG_LITERAL_LEFT_SQUARE_BRACKET 0x5b
+# endif
+# ifndef PNG_LITERAL_RIGHT_SQUARE_BRACKET
+# define PNG_LITERAL_RIGHT_SQUARE_BRACKET 0x5d
+# endif
+# ifndef PNG_STRING_NEWLINE
+# define PNG_STRING_NEWLINE "\n"
+# endif
+
+#ifdef PNG_DEBUG
+# if (PNG_DEBUG > 0)
+# if !defined(PNG_DEBUG_FILE) && defined(_MSC_VER)
+# include <crtdbg.h>
+# if (PNG_DEBUG > 1)
+# ifndef _DEBUG
+# define _DEBUG
+# endif
+# ifndef png_debug
+# define png_debug(l,m) _RPT0(_CRT_WARN,m PNG_STRING_NEWLINE)
+# endif
+# ifndef png_debug1
+# define png_debug1(l,m,p1) _RPT1(_CRT_WARN,m PNG_STRING_NEWLINE,p1)
+# endif
+# ifndef png_debug2
+# define png_debug2(l,m,p1,p2) \
+ _RPT2(_CRT_WARN,m PNG_STRING_NEWLINE,p1,p2)
+# endif
+# endif
+# else /* PNG_DEBUG_FILE || !_MSC_VER */
+# ifndef PNG_STDIO_SUPPORTED
+# include <stdio.h> /* not included yet */
+# endif
+# ifndef PNG_DEBUG_FILE
+# define PNG_DEBUG_FILE stderr
+# endif /* PNG_DEBUG_FILE */
+
+# if (PNG_DEBUG > 1)
+# ifdef __STDC__
+# ifndef png_debug
+# define png_debug(l,m) \
+ do { \
+ int num_tabs=l; \
+ fprintf(PNG_DEBUG_FILE,"%s" m PNG_STRING_NEWLINE,(num_tabs==1 ? " " : \
+ (num_tabs==2 ? " " : (num_tabs>2 ? " " : "")))); \
+ } while (0)
+# endif
+# ifndef png_debug1
+# define png_debug1(l,m,p1) \
+ do { \
+ int num_tabs=l; \
+ fprintf(PNG_DEBUG_FILE,"%s" m PNG_STRING_NEWLINE,(num_tabs==1 ? " " : \
+ (num_tabs==2 ? " " : (num_tabs>2 ? " " : ""))),p1); \
+ } while (0)
+# endif
+# ifndef png_debug2
+# define png_debug2(l,m,p1,p2) \
+ do { \
+ int num_tabs=l; \
+ fprintf(PNG_DEBUG_FILE,"%s" m PNG_STRING_NEWLINE,(num_tabs==1 ? " " : \
+ (num_tabs==2 ? " " : (num_tabs>2 ? " " : ""))),p1,p2);\
+ } while (0)
+# endif
+# else /* __STDC __ */
+# ifndef png_debug
+# define png_debug(l,m) \
+ do { \
+ int num_tabs=l; \
+ char format[256]; \
+ snprintf(format,256,"%s%s%s",(num_tabs==1 ? "\t" : \
+ (num_tabs==2 ? "\t\t":(num_tabs>2 ? "\t\t\t":""))), \
+ m,PNG_STRING_NEWLINE); \
+ fprintf(PNG_DEBUG_FILE,format); \
+ } while (0)
+# endif
+# ifndef png_debug1
+# define png_debug1(l,m,p1) \
+ do { \
+ int num_tabs=l; \
+ char format[256]; \
+ snprintf(format,256,"%s%s%s",(num_tabs==1 ? "\t" : \
+ (num_tabs==2 ? "\t\t":(num_tabs>2 ? "\t\t\t":""))), \
+ m,PNG_STRING_NEWLINE); \
+ fprintf(PNG_DEBUG_FILE,format,p1); \
+ } while (0)
+# endif
+# ifndef png_debug2
+# define png_debug2(l,m,p1,p2) \
+ do { \
+ int num_tabs=l; \
+ char format[256]; \
+ snprintf(format,256,"%s%s%s",(num_tabs==1 ? "\t" : \
+ (num_tabs==2 ? "\t\t":(num_tabs>2 ? "\t\t\t":""))), \
+ m,PNG_STRING_NEWLINE); \
+ fprintf(PNG_DEBUG_FILE,format,p1,p2); \
+ } while (0)
+# endif
+# endif /* __STDC __ */
+# endif /* (PNG_DEBUG > 1) */
+
+# endif /* _MSC_VER */
+# endif /* (PNG_DEBUG > 0) */
+#endif /* PNG_DEBUG */
+#ifndef png_debug
+# define png_debug(l, m) ((void)0)
+#endif
+#ifndef png_debug1
+# define png_debug1(l, m, p1) ((void)0)
+#endif
+#ifndef png_debug2
+# define png_debug2(l, m, p1, p2) ((void)0)
+#endif
+#endif /* PNGDEBUG_H */
--- /dev/null
+
+/* pngerror.c - stub functions for i/o and memory allocation
+ *
+ * Last changed in libpng 1.6.15 [November 20, 2014]
+ * Copyright (c) 1998-2014 Glenn Randers-Pehrson
+ * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
+ * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ *
+ * This file provides a location for all error handling. Users who
+ * need special error handling are expected to write replacement functions
+ * and use png_set_error_fn() to use those functions. See the instructions
+ * at each function.
+ */
+
+#include "pngpriv.h"
+
+#if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
+
+static PNG_FUNCTION(void, png_default_error,PNGARG((png_const_structrp png_ptr,
+ png_const_charp error_message)),PNG_NORETURN);
+
+#ifdef PNG_WARNINGS_SUPPORTED
+static void /* PRIVATE */
+png_default_warning PNGARG((png_const_structrp png_ptr,
+ png_const_charp warning_message));
+#endif /* WARNINGS */
+
+/* This function is called whenever there is a fatal error. This function
+ * should not be changed. If there is a need to handle errors differently,
+ * you should supply a replacement error function and use png_set_error_fn()
+ * to replace the error function at run-time.
+ */
+#ifdef PNG_ERROR_TEXT_SUPPORTED
+PNG_FUNCTION(void,PNGAPI
+png_error,(png_const_structrp png_ptr, png_const_charp error_message),
+ PNG_NORETURN)
+{
+#ifdef PNG_ERROR_NUMBERS_SUPPORTED
+ char msg[16];
+ if (png_ptr != NULL)
+ {
+ if ((png_ptr->flags &
+ (PNG_FLAG_STRIP_ERROR_NUMBERS|PNG_FLAG_STRIP_ERROR_TEXT)) != 0
+ {
+ if (*error_message == PNG_LITERAL_SHARP)
+ {
+ /* Strip "#nnnn " from beginning of error message. */
+ int offset;
+ for (offset = 1; offset<15; offset++)
+ if (error_message[offset] == ' ')
+ break;
+
+ if ((png_ptr->flags & PNG_FLAG_STRIP_ERROR_TEXT) != 0)
+ {
+ int i;
+ for (i = 0; i < offset - 1; i++)
+ msg[i] = error_message[i + 1];
+ msg[i - 1] = '\0';
+ error_message = msg;
+ }
+
+ else
+ error_message += offset;
+ }
+
+ else
+ {
+ if ((png_ptr->flags & PNG_FLAG_STRIP_ERROR_TEXT) != 0)
+ {
+ msg[0] = '0';
+ msg[1] = '\0';
+ error_message = msg;
+ }
+ }
+ }
+ }
+#endif
+ if (png_ptr != NULL && png_ptr->error_fn != NULL)
+ (*(png_ptr->error_fn))(png_constcast(png_structrp,png_ptr),
+ error_message);
+
+ /* If the custom handler doesn't exist, or if it returns,
+ use the default handler, which will not return. */
+ png_default_error(png_ptr, error_message);
+}
+#else
+PNG_FUNCTION(void,PNGAPI
+png_err,(png_const_structrp png_ptr),PNG_NORETURN)
+{
+ /* Prior to 1.5.2 the error_fn received a NULL pointer, expressed
+ * erroneously as '\0', instead of the empty string "". This was
+ * apparently an error, introduced in libpng-1.2.20, and png_default_error
+ * will crash in this case.
+ */
+ if (png_ptr != NULL && png_ptr->error_fn != NULL)
+ (*(png_ptr->error_fn))(png_constcast(png_structrp,png_ptr), "");
+
+ /* If the custom handler doesn't exist, or if it returns,
+ use the default handler, which will not return. */
+ png_default_error(png_ptr, "");
+}
+#endif /* ERROR_TEXT */
+
+/* Utility to safely appends strings to a buffer. This never errors out so
+ * error checking is not required in the caller.
+ */
+size_t
+png_safecat(png_charp buffer, size_t bufsize, size_t pos,
+ png_const_charp string)
+{
+ if (buffer != NULL && pos < bufsize)
+ {
+ if (string != NULL)
+ while (*string != '\0' && pos < bufsize-1)
+ buffer[pos++] = *string++;
+
+ buffer[pos] = '\0';
+ }
+
+ return pos;
+}
+
+#if defined(PNG_WARNINGS_SUPPORTED) || defined(PNG_TIME_RFC1123_SUPPORTED)
+/* Utility to dump an unsigned value into a buffer, given a start pointer and
+ * and end pointer (which should point just *beyond* the end of the buffer!)
+ * Returns the pointer to the start of the formatted string.
+ */
+png_charp
+png_format_number(png_const_charp start, png_charp end, int format,
+ png_alloc_size_t number)
+{
+ int count = 0; /* number of digits output */
+ int mincount = 1; /* minimum number required */
+ int output = 0; /* digit output (for the fixed point format) */
+
+ *--end = '\0';
+
+ /* This is written so that the loop always runs at least once, even with
+ * number zero.
+ */
+ while (end > start && (number != 0 || count < mincount))
+ {
+
+ static const char digits[] = "0123456789ABCDEF";
+
+ switch (format)
+ {
+ case PNG_NUMBER_FORMAT_fixed:
+ /* Needs five digits (the fraction) */
+ mincount = 5;
+ if (output != 0 || number % 10 != 0)
+ {
+ *--end = digits[number % 10];
+ output = 1;
+ }
+ number /= 10;
+ break;
+
+ case PNG_NUMBER_FORMAT_02u:
+ /* Expects at least 2 digits. */
+ mincount = 2;
+ /* FALL THROUGH */
+
+ case PNG_NUMBER_FORMAT_u:
+ *--end = digits[number % 10];
+ number /= 10;
+ break;
+
+ case PNG_NUMBER_FORMAT_02x:
+ /* This format expects at least two digits */
+ mincount = 2;
+ /* FALL THROUGH */
+
+ case PNG_NUMBER_FORMAT_x:
+ *--end = digits[number & 0xf];
+ number >>= 4;
+ break;
+
+ default: /* an error */
+ number = 0;
+ break;
+ }
+
+ /* Keep track of the number of digits added */
+ ++count;
+
+ /* Float a fixed number here: */
+ if ((format == PNG_NUMBER_FORMAT_fixed) && (count == 5) && (end > start))
+ {
+ /* End of the fraction, but maybe nothing was output? In that case
+ * drop the decimal point. If the number is a true zero handle that
+ * here.
+ */
+ if (output != 0)
+ *--end = '.';
+ else if (number == 0) /* and !output */
+ *--end = '0';
+ }
+ }
+
+ return end;
+}
+#endif
+
+#ifdef PNG_WARNINGS_SUPPORTED
+/* This function is called whenever there is a non-fatal error. This function
+ * should not be changed. If there is a need to handle warnings differently,
+ * you should supply a replacement warning function and use
+ * png_set_error_fn() to replace the warning function at run-time.
+ */
+void PNGAPI
+png_warning(png_const_structrp png_ptr, png_const_charp warning_message)
+{
+ int offset = 0;
+ if (png_ptr != NULL)
+ {
+#ifdef PNG_ERROR_NUMBERS_SUPPORTED
+ if ((png_ptr->flags &
+ (PNG_FLAG_STRIP_ERROR_NUMBERS|PNG_FLAG_STRIP_ERROR_TEXT)) != 0)
+#endif
+ {
+ if (*warning_message == PNG_LITERAL_SHARP)
+ {
+ for (offset = 1; offset < 15; offset++)
+ if (warning_message[offset] == ' ')
+ break;
+ }
+ }
+ }
+ if (png_ptr != NULL && png_ptr->warning_fn != NULL)
+ (*(png_ptr->warning_fn))(png_constcast(png_structrp,png_ptr),
+ warning_message + offset);
+ else
+ png_default_warning(png_ptr, warning_message + offset);
+}
+
+/* These functions support 'formatted' warning messages with up to
+ * PNG_WARNING_PARAMETER_COUNT parameters. In the format string the parameter
+ * is introduced by @<number>, where 'number' starts at 1. This follows the
+ * standard established by X/Open for internationalizable error messages.
+ */
+void
+png_warning_parameter(png_warning_parameters p, int number,
+ png_const_charp string)
+{
+ if (number > 0 && number <= PNG_WARNING_PARAMETER_COUNT)
+ (void)png_safecat(p[number-1], (sizeof p[number-1]), 0, string);
+}
+
+void
+png_warning_parameter_unsigned(png_warning_parameters p, int number, int format,
+ png_alloc_size_t value)
+{
+ char buffer[PNG_NUMBER_BUFFER_SIZE];
+ png_warning_parameter(p, number, PNG_FORMAT_NUMBER(buffer, format, value));
+}
+
+void
+png_warning_parameter_signed(png_warning_parameters p, int number, int format,
+ png_int_32 value)
+{
+ png_alloc_size_t u;
+ png_charp str;
+ char buffer[PNG_NUMBER_BUFFER_SIZE];
+
+ /* Avoid overflow by doing the negate in a png_alloc_size_t: */
+ u = (png_alloc_size_t)value;
+ if (value < 0)
+ u = ~u + 1;
+
+ str = PNG_FORMAT_NUMBER(buffer, format, u);
+
+ if (value < 0 && str > buffer)
+ *--str = '-';
+
+ png_warning_parameter(p, number, str);
+}
+
+void
+png_formatted_warning(png_const_structrp png_ptr, png_warning_parameters p,
+ png_const_charp message)
+{
+ /* The internal buffer is just 192 bytes - enough for all our messages,
+ * overflow doesn't happen because this code checks! If someone figures
+ * out how to send us a message longer than 192 bytes, all that will
+ * happen is that the message will be truncated appropriately.
+ */
+ size_t i = 0; /* Index in the msg[] buffer: */
+ char msg[192];
+
+ /* Each iteration through the following loop writes at most one character
+ * to msg[i++] then returns here to validate that there is still space for
+ * the trailing '\0'. It may (in the case of a parameter) read more than
+ * one character from message[]; it must check for '\0' and continue to the
+ * test if it finds the end of string.
+ */
+ while (i<(sizeof msg)-1 && *message != '\0')
+ {
+ /* '@' at end of string is now just printed (previously it was skipped);
+ * it is an error in the calling code to terminate the string with @.
+ */
+ if (p != NULL && *message == '@' && message[1] != '\0')
+ {
+ int parameter_char = *++message; /* Consume the '@' */
+ static const char valid_parameters[] = "123456789";
+ int parameter = 0;
+
+ /* Search for the parameter digit, the index in the string is the
+ * parameter to use.
+ */
+ while (valid_parameters[parameter] != parameter_char &&
+ valid_parameters[parameter] != '\0')
+ ++parameter;
+
+ /* If the parameter digit is out of range it will just get printed. */
+ if (parameter < PNG_WARNING_PARAMETER_COUNT)
+ {
+ /* Append this parameter */
+ png_const_charp parm = p[parameter];
+ png_const_charp pend = p[parameter] + (sizeof p[parameter]);
+
+ /* No need to copy the trailing '\0' here, but there is no guarantee
+ * that parm[] has been initialized, so there is no guarantee of a
+ * trailing '\0':
+ */
+ while (i<(sizeof msg)-1 && *parm != '\0' && parm < pend)
+ msg[i++] = *parm++;
+
+ /* Consume the parameter digit too: */
+ ++message;
+ continue;
+ }
+
+ /* else not a parameter and there is a character after the @ sign; just
+ * copy that. This is known not to be '\0' because of the test above.
+ */
+ }
+
+ /* At this point *message can't be '\0', even in the bad parameter case
+ * above where there is a lone '@' at the end of the message string.
+ */
+ msg[i++] = *message++;
+ }
+
+ /* i is always less than (sizeof msg), so: */
+ msg[i] = '\0';
+
+ /* And this is the formatted message. It may be larger than
+ * PNG_MAX_ERROR_TEXT, but that is only used for 'chunk' errors and these
+ * are not (currently) formatted.
+ */
+ png_warning(png_ptr, msg);
+}
+#endif /* WARNINGS */
+
+#ifdef PNG_BENIGN_ERRORS_SUPPORTED
+void PNGAPI
+png_benign_error(png_const_structrp png_ptr, png_const_charp error_message)
+{
+ if ((png_ptr->flags & PNG_FLAG_BENIGN_ERRORS_WARN) != 0)
+ {
+# ifdef PNG_READ_SUPPORTED
+ if ((png_ptr->mode & PNG_IS_READ_STRUCT) != 0 &&
+ png_ptr->chunk_name != 0)
+ png_chunk_warning(png_ptr, error_message);
+ else
+# endif
+ png_warning(png_ptr, error_message);
+ }
+
+ else
+ {
+# ifdef PNG_READ_SUPPORTED
+ if ((png_ptr->mode & PNG_IS_READ_STRUCT) != 0 &&
+ png_ptr->chunk_name != 0)
+ png_chunk_error(png_ptr, error_message);
+ else
+# endif
+ png_error(png_ptr, error_message);
+ }
+
+# ifndef PNG_ERROR_TEXT_SUPPORTED
+ PNG_UNUSED(error_message)
+# endif
+}
+
+void /* PRIVATE */
+png_app_warning(png_const_structrp png_ptr, png_const_charp error_message)
+{
+ if ((png_ptr->flags & PNG_FLAG_APP_WARNINGS_WARN) != 0)
+ png_warning(png_ptr, error_message);
+ else
+ png_error(png_ptr, error_message);
+
+# ifndef PNG_ERROR_TEXT_SUPPORTED
+ PNG_UNUSED(error_message)
+# endif
+}
+
+void /* PRIVATE */
+png_app_error(png_const_structrp png_ptr, png_const_charp error_message)
+{
+ if ((png_ptr->flags & PNG_FLAG_APP_ERRORS_WARN) != 0)
+ png_warning(png_ptr, error_message);
+ else
+ png_error(png_ptr, error_message);
+
+# ifndef PNG_ERROR_TEXT_SUPPORTED
+ PNG_UNUSED(error_message)
+# endif
+}
+#endif /* BENIGN_ERRORS */
+
+#define PNG_MAX_ERROR_TEXT 196 /* Currently limited by profile_error in png.c */
+#if defined(PNG_WARNINGS_SUPPORTED) || \
+ (defined(PNG_READ_SUPPORTED) && defined(PNG_ERROR_TEXT_SUPPORTED))
+/* These utilities are used internally to build an error message that relates
+ * to the current chunk. The chunk name comes from png_ptr->chunk_name,
+ * which is used to prefix the message. The message is limited in length
+ * to 63 bytes. The name characters are output as hex digits wrapped in []
+ * if the character is invalid.
+ */
+#define isnonalpha(c) ((c) < 65 || (c) > 122 || ((c) > 90 && (c) < 97))
+static PNG_CONST char png_digit[16] = {
+ '0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
+ 'A', 'B', 'C', 'D', 'E', 'F'
+};
+
+static void /* PRIVATE */
+png_format_buffer(png_const_structrp png_ptr, png_charp buffer, png_const_charp
+ error_message)
+{
+ png_uint_32 chunk_name = png_ptr->chunk_name;
+ int iout = 0, ishift = 24;
+
+ while (ishift >= 0)
+ {
+ int c = (int)(chunk_name >> ishift) & 0xff;
+
+ ishift -= 8;
+ if (isnonalpha(c) != 0)
+ {
+ buffer[iout++] = PNG_LITERAL_LEFT_SQUARE_BRACKET;
+ buffer[iout++] = png_digit[(c & 0xf0) >> 4];
+ buffer[iout++] = png_digit[c & 0x0f];
+ buffer[iout++] = PNG_LITERAL_RIGHT_SQUARE_BRACKET;
+ }
+
+ else
+ {
+ buffer[iout++] = (char)c;
+ }
+ }
+
+ if (error_message == NULL)
+ buffer[iout] = '\0';
+
+ else
+ {
+ int iin = 0;
+
+ buffer[iout++] = ':';
+ buffer[iout++] = ' ';
+
+ while (iin < PNG_MAX_ERROR_TEXT-1 && error_message[iin] != '\0')
+ buffer[iout++] = error_message[iin++];
+
+ /* iin < PNG_MAX_ERROR_TEXT, so the following is safe: */
+ buffer[iout] = '\0';
+ }
+}
+#endif /* WARNINGS || ERROR_TEXT */
+
+#if defined(PNG_READ_SUPPORTED) && defined(PNG_ERROR_TEXT_SUPPORTED)
+PNG_FUNCTION(void,PNGAPI
+png_chunk_error,(png_const_structrp png_ptr, png_const_charp error_message),
+ PNG_NORETURN)
+{
+ char msg[18+PNG_MAX_ERROR_TEXT];
+ if (png_ptr == NULL)
+ png_error(png_ptr, error_message);
+
+ else
+ {
+ png_format_buffer(png_ptr, msg, error_message);
+ png_error(png_ptr, msg);
+ }
+}
+#endif /* READ && ERROR_TEXT */
+
+#ifdef PNG_WARNINGS_SUPPORTED
+void PNGAPI
+png_chunk_warning(png_const_structrp png_ptr, png_const_charp warning_message)
+{
+ char msg[18+PNG_MAX_ERROR_TEXT];
+ if (png_ptr == NULL)
+ png_warning(png_ptr, warning_message);
+
+ else
+ {
+ png_format_buffer(png_ptr, msg, warning_message);
+ png_warning(png_ptr, msg);
+ }
+}
+#endif /* WARNINGS */
+
+#ifdef PNG_READ_SUPPORTED
+#ifdef PNG_BENIGN_ERRORS_SUPPORTED
+void PNGAPI
+png_chunk_benign_error(png_const_structrp png_ptr, png_const_charp
+ error_message)
+{
+ if ((png_ptr->flags & PNG_FLAG_BENIGN_ERRORS_WARN) != 0)
+ png_chunk_warning(png_ptr, error_message);
+
+ else
+ png_chunk_error(png_ptr, error_message);
+
+# ifndef PNG_ERROR_TEXT_SUPPORTED
+ PNG_UNUSED(error_message)
+# endif
+}
+#endif
+#endif /* READ */
+
+void /* PRIVATE */
+png_chunk_report(png_const_structrp png_ptr, png_const_charp message, int error)
+{
+# ifndef PNG_WARNINGS_SUPPORTED
+ PNG_UNUSED(message)
+# endif
+
+ /* This is always supported, but for just read or just write it
+ * unconditionally does the right thing.
+ */
+# if defined(PNG_READ_SUPPORTED) && defined(PNG_WRITE_SUPPORTED)
+ if ((png_ptr->mode & PNG_IS_READ_STRUCT) != 0)
+# endif
+
+# ifdef PNG_READ_SUPPORTED
+ {
+ if (error < PNG_CHUNK_ERROR)
+ png_chunk_warning(png_ptr, message);
+
+ else
+ png_chunk_benign_error(png_ptr, message);
+ }
+# endif
+
+# if defined(PNG_READ_SUPPORTED) && defined(PNG_WRITE_SUPPORTED)
+ else if ((png_ptr->mode & PNG_IS_READ_STRUCT) == 0)
+# endif
+
+# ifdef PNG_WRITE_SUPPORTED
+ {
+ if (error < PNG_CHUNK_WRITE_ERROR)
+ png_app_warning(png_ptr, message);
+
+ else
+ png_app_error(png_ptr, message);
+ }
+# endif
+}
+
+#ifdef PNG_ERROR_TEXT_SUPPORTED
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+PNG_FUNCTION(void,
+png_fixed_error,(png_const_structrp png_ptr, png_const_charp name),PNG_NORETURN)
+{
+# define fixed_message "fixed point overflow in "
+# define fixed_message_ln ((sizeof fixed_message)-1)
+ int iin;
+ char msg[fixed_message_ln+PNG_MAX_ERROR_TEXT];
+ memcpy(msg, fixed_message, fixed_message_ln);
+ iin = 0;
+ if (name != NULL)
+ while (iin < (PNG_MAX_ERROR_TEXT-1) && name[iin] != 0)
+ {
+ msg[fixed_message_ln + iin] = name[iin];
+ ++iin;
+ }
+ msg[fixed_message_ln + iin] = 0;
+ png_error(png_ptr, msg);
+}
+#endif
+#endif
+
+#ifdef PNG_SETJMP_SUPPORTED
+/* This API only exists if ANSI-C style error handling is used,
+ * otherwise it is necessary for png_default_error to be overridden.
+ */
+jmp_buf* PNGAPI
+png_set_longjmp_fn(png_structrp png_ptr, png_longjmp_ptr longjmp_fn,
+ size_t jmp_buf_size)
+{
+ /* From libpng 1.6.0 the app gets one chance to set a 'jmpbuf_size' value
+ * and it must not change after that. Libpng doesn't care how big the
+ * buffer is, just that it doesn't change.
+ *
+ * If the buffer size is no *larger* than the size of jmp_buf when libpng is
+ * compiled a built in jmp_buf is returned; this preserves the pre-1.6.0
+ * semantics that this call will not fail. If the size is larger, however,
+ * the buffer is allocated and this may fail, causing the function to return
+ * NULL.
+ */
+ if (png_ptr == NULL)
+ return NULL;
+
+ if (png_ptr->jmp_buf_ptr == NULL)
+ {
+ png_ptr->jmp_buf_size = 0; /* not allocated */
+
+ if (jmp_buf_size <= (sizeof png_ptr->jmp_buf_local))
+ png_ptr->jmp_buf_ptr = &png_ptr->jmp_buf_local;
+
+ else
+ {
+ png_ptr->jmp_buf_ptr = png_voidcast(jmp_buf *,
+ png_malloc_warn(png_ptr, jmp_buf_size));
+
+ if (png_ptr->jmp_buf_ptr == NULL)
+ return NULL; /* new NULL return on OOM */
+
+ png_ptr->jmp_buf_size = jmp_buf_size;
+ }
+ }
+
+ else /* Already allocated: check the size */
+ {
+ size_t size = png_ptr->jmp_buf_size;
+
+ if (size == 0)
+ {
+ size = (sizeof png_ptr->jmp_buf_local);
+ if (png_ptr->jmp_buf_ptr != &png_ptr->jmp_buf_local)
+ {
+ /* This is an internal error in libpng: somehow we have been left
+ * with a stack allocated jmp_buf when the application regained
+ * control. It's always possible to fix this up, but for the moment
+ * this is a png_error because that makes it easy to detect.
+ */
+ png_error(png_ptr, "Libpng jmp_buf still allocated");
+ /* png_ptr->jmp_buf_ptr = &png_ptr->jmp_buf_local; */
+ }
+ }
+
+ if (size != jmp_buf_size)
+ {
+ png_warning(png_ptr, "Application jmp_buf size changed");
+ return NULL; /* caller will probably crash: no choice here */
+ }
+ }
+
+ /* Finally fill in the function, now we have a satisfactory buffer. It is
+ * valid to change the function on every call.
+ */
+ png_ptr->longjmp_fn = longjmp_fn;
+ return png_ptr->jmp_buf_ptr;
+}
+
+void /* PRIVATE */
+png_free_jmpbuf(png_structrp png_ptr)
+{
+ if (png_ptr != NULL)
+ {
+ jmp_buf *jb = png_ptr->jmp_buf_ptr;
+
+ /* A size of 0 is used to indicate a local, stack, allocation of the
+ * pointer; used here and in png.c
+ */
+ if (jb != NULL && png_ptr->jmp_buf_size > 0)
+ {
+
+ /* This stuff is so that a failure to free the error control structure
+ * does not leave libpng in a state with no valid error handling: the
+ * free always succeeds, if there is an error it gets ignored.
+ */
+ if (jb != &png_ptr->jmp_buf_local)
+ {
+ /* Make an internal, libpng, jmp_buf to return here */
+ jmp_buf free_jmp_buf;
+
+ if (!setjmp(free_jmp_buf))
+ {
+ png_ptr->jmp_buf_ptr = &free_jmp_buf; /* come back here */
+ png_ptr->jmp_buf_size = 0; /* stack allocation */
+ png_ptr->longjmp_fn = longjmp;
+ png_free(png_ptr, jb); /* Return to setjmp on error */
+ }
+ }
+ }
+
+ /* *Always* cancel everything out: */
+ png_ptr->jmp_buf_size = 0;
+ png_ptr->jmp_buf_ptr = NULL;
+ png_ptr->longjmp_fn = 0;
+ }
+}
+#endif
+
+/* This is the default error handling function. Note that replacements for
+ * this function MUST NOT RETURN, or the program will likely crash. This
+ * function is used by default, or if the program supplies NULL for the
+ * error function pointer in png_set_error_fn().
+ */
+static PNG_FUNCTION(void /* PRIVATE */,
+png_default_error,(png_const_structrp png_ptr, png_const_charp error_message),
+ PNG_NORETURN)
+{
+#ifdef PNG_CONSOLE_IO_SUPPORTED
+#ifdef PNG_ERROR_NUMBERS_SUPPORTED
+ /* Check on NULL only added in 1.5.4 */
+ if (error_message != NULL && *error_message == PNG_LITERAL_SHARP)
+ {
+ /* Strip "#nnnn " from beginning of error message. */
+ int offset;
+ char error_number[16];
+ for (offset = 0; offset<15; offset++)
+ {
+ error_number[offset] = error_message[offset + 1];
+ if (error_message[offset] == ' ')
+ break;
+ }
+
+ if ((offset > 1) && (offset < 15))
+ {
+ error_number[offset - 1] = '\0';
+ fprintf(stderr, "libpng error no. %s: %s",
+ error_number, error_message + offset + 1);
+ fprintf(stderr, PNG_STRING_NEWLINE);
+ }
+
+ else
+ {
+ fprintf(stderr, "libpng error: %s, offset=%d",
+ error_message, offset);
+ fprintf(stderr, PNG_STRING_NEWLINE);
+ }
+ }
+ else
+#endif
+ {
+ fprintf(stderr, "libpng error: %s", error_message ? error_message :
+ "undefined");
+ fprintf(stderr, PNG_STRING_NEWLINE);
+ }
+#else
+ PNG_UNUSED(error_message) /* Make compiler happy */
+#endif
+ png_longjmp(png_ptr, 1);
+}
+
+PNG_FUNCTION(void,PNGAPI
+png_longjmp,(png_const_structrp png_ptr, int val),PNG_NORETURN)
+{
+#ifdef PNG_SETJMP_SUPPORTED
+ if (png_ptr != NULL && png_ptr->longjmp_fn != NULL &&
+ png_ptr->jmp_buf_ptr != NULL)
+ png_ptr->longjmp_fn(*png_ptr->jmp_buf_ptr, val);
+#else
+ PNG_UNUSED(png_ptr)
+ PNG_UNUSED(val)
+#endif
+
+ /* If control reaches this point, png_longjmp() must not return. The only
+ * choice is to terminate the whole process (or maybe the thread); to do
+ * this the ANSI-C abort() function is used unless a different method is
+ * implemented by overriding the default configuration setting for
+ * PNG_ABORT().
+ */
+ PNG_ABORT();
+}
+
+#ifdef PNG_WARNINGS_SUPPORTED
+/* This function is called when there is a warning, but the library thinks
+ * it can continue anyway. Replacement functions don't have to do anything
+ * here if you don't want them to. In the default configuration, png_ptr is
+ * not used, but it is passed in case it may be useful.
+ */
+static void /* PRIVATE */
+png_default_warning(png_const_structrp png_ptr, png_const_charp warning_message)
+{
+#ifdef PNG_CONSOLE_IO_SUPPORTED
+# ifdef PNG_ERROR_NUMBERS_SUPPORTED
+ if (*warning_message == PNG_LITERAL_SHARP)
+ {
+ int offset;
+ char warning_number[16];
+ for (offset = 0; offset < 15; offset++)
+ {
+ warning_number[offset] = warning_message[offset + 1];
+ if (warning_message[offset] == ' ')
+ break;
+ }
+
+ if ((offset > 1) && (offset < 15))
+ {
+ warning_number[offset + 1] = '\0';
+ fprintf(stderr, "libpng warning no. %s: %s",
+ warning_number, warning_message + offset);
+ fprintf(stderr, PNG_STRING_NEWLINE);
+ }
+
+ else
+ {
+ fprintf(stderr, "libpng warning: %s",
+ warning_message);
+ fprintf(stderr, PNG_STRING_NEWLINE);
+ }
+ }
+ else
+# endif
+
+ {
+ fprintf(stderr, "libpng warning: %s", warning_message);
+ fprintf(stderr, PNG_STRING_NEWLINE);
+ }
+#else
+ PNG_UNUSED(warning_message) /* Make compiler happy */
+#endif
+ PNG_UNUSED(png_ptr) /* Make compiler happy */
+}
+#endif /* WARNINGS */
+
+/* This function is called when the application wants to use another method
+ * of handling errors and warnings. Note that the error function MUST NOT
+ * return to the calling routine or serious problems will occur. The return
+ * method used in the default routine calls longjmp(png_ptr->jmp_buf_ptr, 1)
+ */
+void PNGAPI
+png_set_error_fn(png_structrp png_ptr, png_voidp error_ptr,
+ png_error_ptr error_fn, png_error_ptr warning_fn)
+{
+ if (png_ptr == NULL)
+ return;
+
+ png_ptr->error_ptr = error_ptr;
+ png_ptr->error_fn = error_fn;
+#ifdef PNG_WARNINGS_SUPPORTED
+ png_ptr->warning_fn = warning_fn;
+#else
+ PNG_UNUSED(warning_fn)
+#endif
+}
+
+
+/* This function returns a pointer to the error_ptr associated with the user
+ * functions. The application should free any memory associated with this
+ * pointer before png_write_destroy and png_read_destroy are called.
+ */
+png_voidp PNGAPI
+png_get_error_ptr(png_const_structrp png_ptr)
+{
+ if (png_ptr == NULL)
+ return NULL;
+
+ return ((png_voidp)png_ptr->error_ptr);
+}
+
+
+#ifdef PNG_ERROR_NUMBERS_SUPPORTED
+void PNGAPI
+png_set_strip_error_numbers(png_structrp png_ptr, png_uint_32 strip_mode)
+{
+ if (png_ptr != NULL)
+ {
+ png_ptr->flags &=
+ ((~(PNG_FLAG_STRIP_ERROR_NUMBERS |
+ PNG_FLAG_STRIP_ERROR_TEXT))&strip_mode);
+ }
+}
+#endif
+
+#if defined(PNG_SIMPLIFIED_READ_SUPPORTED) ||\
+ defined(PNG_SIMPLIFIED_WRITE_SUPPORTED)
+ /* Currently the above both depend on SETJMP_SUPPORTED, however it would be
+ * possible to implement without setjmp support just so long as there is some
+ * way to handle the error return here:
+ */
+PNG_FUNCTION(void /* PRIVATE */, (PNGCBAPI
+png_safe_error),(png_structp png_nonconst_ptr, png_const_charp error_message),
+ PNG_NORETURN)
+{
+ const png_const_structrp png_ptr = png_nonconst_ptr;
+ png_imagep image = png_voidcast(png_imagep, png_ptr->error_ptr);
+
+ /* An error is always logged here, overwriting anything (typically a warning)
+ * that is already there:
+ */
+ if (image != NULL)
+ {
+ png_safecat(image->message, (sizeof image->message), 0, error_message);
+ image->warning_or_error |= PNG_IMAGE_ERROR;
+
+ /* Retrieve the jmp_buf from within the png_control, making this work for
+ * C++ compilation too is pretty tricky: C++ wants a pointer to the first
+ * element of a jmp_buf, but C doesn't tell us the type of that.
+ */
+ if (image->opaque != NULL && image->opaque->error_buf != NULL)
+ longjmp(png_control_jmp_buf(image->opaque), 1);
+
+ /* Missing longjmp buffer, the following is to help debugging: */
+ {
+ size_t pos = png_safecat(image->message, (sizeof image->message), 0,
+ "bad longjmp: ");
+ png_safecat(image->message, (sizeof image->message), pos,
+ error_message);
+ }
+ }
+
+ /* Here on an internal programming error. */
+ abort();
+}
+
+#ifdef PNG_WARNINGS_SUPPORTED
+void /* PRIVATE */ PNGCBAPI
+png_safe_warning(png_structp png_nonconst_ptr, png_const_charp warning_message)
+{
+ const png_const_structrp png_ptr = png_nonconst_ptr;
+ png_imagep image = png_voidcast(png_imagep, png_ptr->error_ptr);
+
+ /* A warning is only logged if there is no prior warning or error. */
+ if (image->warning_or_error == 0)
+ {
+ png_safecat(image->message, (sizeof image->message), 0, warning_message);
+ image->warning_or_error |= PNG_IMAGE_WARNING;
+ }
+}
+#endif
+
+int /* PRIVATE */
+png_safe_execute(png_imagep image_in, int (*function)(png_voidp), png_voidp arg)
+{
+ volatile png_imagep image = image_in;
+ volatile int result;
+ volatile png_voidp saved_error_buf;
+ jmp_buf safe_jmpbuf;
+
+ /* Safely execute function(arg) with png_error returning to this function. */
+ saved_error_buf = image->opaque->error_buf;
+ result = setjmp(safe_jmpbuf) == 0;
+
+ if (result != 0)
+ {
+
+ image->opaque->error_buf = safe_jmpbuf;
+ result = function(arg);
+ }
+
+ image->opaque->error_buf = saved_error_buf;
+
+ /* And do the cleanup prior to any failure return. */
+ if (result == 0)
+ png_image_free(image);
+
+ return result;
+}
+#endif /* SIMPLIFIED READ || SIMPLIFIED_WRITE */
+#endif /* READ || WRITE */
--- /dev/null
+
+/* pngget.c - retrieval of values from info struct
+ *
+ * Last changed in libpng 1.6.17 [March 26, 2015]
+ * Copyright (c) 1998-2015 Glenn Randers-Pehrson
+ * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
+ * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ *
+ */
+
+#include "pngpriv.h"
+
+#if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
+
+png_uint_32 PNGAPI
+png_get_valid(png_const_structrp png_ptr, png_const_inforp info_ptr,
+ png_uint_32 flag)
+{
+ if (png_ptr != NULL && info_ptr != NULL)
+ return(info_ptr->valid & flag);
+
+ return(0);
+}
+
+png_size_t PNGAPI
+png_get_rowbytes(png_const_structrp png_ptr, png_const_inforp info_ptr)
+{
+ if (png_ptr != NULL && info_ptr != NULL)
+ return(info_ptr->rowbytes);
+
+ return(0);
+}
+
+#ifdef PNG_INFO_IMAGE_SUPPORTED
+png_bytepp PNGAPI
+png_get_rows(png_const_structrp png_ptr, png_const_inforp info_ptr)
+{
+ if (png_ptr != NULL && info_ptr != NULL)
+ return(info_ptr->row_pointers);
+
+ return(0);
+}
+#endif
+
+#ifdef PNG_EASY_ACCESS_SUPPORTED
+/* Easy access to info, added in libpng-0.99 */
+png_uint_32 PNGAPI
+png_get_image_width(png_const_structrp png_ptr, png_const_inforp info_ptr)
+{
+ if (png_ptr != NULL && info_ptr != NULL)
+ return info_ptr->width;
+
+ return (0);
+}
+
+png_uint_32 PNGAPI
+png_get_image_height(png_const_structrp png_ptr, png_const_inforp info_ptr)
+{
+ if (png_ptr != NULL && info_ptr != NULL)
+ return info_ptr->height;
+
+ return (0);
+}
+
+png_byte PNGAPI
+png_get_bit_depth(png_const_structrp png_ptr, png_const_inforp info_ptr)
+{
+ if (png_ptr != NULL && info_ptr != NULL)
+ return info_ptr->bit_depth;
+
+ return (0);
+}
+
+png_byte PNGAPI
+png_get_color_type(png_const_structrp png_ptr, png_const_inforp info_ptr)
+{
+ if (png_ptr != NULL && info_ptr != NULL)
+ return info_ptr->color_type;
+
+ return (0);
+}
+
+png_byte PNGAPI
+png_get_filter_type(png_const_structrp png_ptr, png_const_inforp info_ptr)
+{
+ if (png_ptr != NULL && info_ptr != NULL)
+ return info_ptr->filter_type;
+
+ return (0);
+}
+
+png_byte PNGAPI
+png_get_interlace_type(png_const_structrp png_ptr, png_const_inforp info_ptr)
+{
+ if (png_ptr != NULL && info_ptr != NULL)
+ return info_ptr->interlace_type;
+
+ return (0);
+}
+
+png_byte PNGAPI
+png_get_compression_type(png_const_structrp png_ptr, png_const_inforp info_ptr)
+{
+ if (png_ptr != NULL && info_ptr != NULL)
+ return info_ptr->compression_type;
+
+ return (0);
+}
+
+png_uint_32 PNGAPI
+png_get_x_pixels_per_meter(png_const_structrp png_ptr, png_const_inforp
+ info_ptr)
+{
+#ifdef PNG_pHYs_SUPPORTED
+ if (png_ptr != NULL && info_ptr != NULL &&
+ (info_ptr->valid & PNG_INFO_pHYs) != 0)
+ {
+ png_debug1(1, "in %s retrieval function",
+ "png_get_x_pixels_per_meter");
+
+ if (info_ptr->phys_unit_type == PNG_RESOLUTION_METER)
+ return (info_ptr->x_pixels_per_unit);
+ }
+#else
+ PNG_UNUSED(png_ptr)
+ PNG_UNUSED(info_ptr)
+#endif
+
+ return (0);
+}
+
+png_uint_32 PNGAPI
+png_get_y_pixels_per_meter(png_const_structrp png_ptr, png_const_inforp
+ info_ptr)
+{
+#ifdef PNG_pHYs_SUPPORTED
+ if (png_ptr != NULL && info_ptr != NULL &&
+ (info_ptr->valid & PNG_INFO_pHYs) != 0)
+ {
+ png_debug1(1, "in %s retrieval function",
+ "png_get_y_pixels_per_meter");
+
+ if (info_ptr->phys_unit_type == PNG_RESOLUTION_METER)
+ return (info_ptr->y_pixels_per_unit);
+ }
+#else
+ PNG_UNUSED(png_ptr)
+ PNG_UNUSED(info_ptr)
+#endif
+
+ return (0);
+}
+
+png_uint_32 PNGAPI
+png_get_pixels_per_meter(png_const_structrp png_ptr, png_const_inforp info_ptr)
+{
+#ifdef PNG_pHYs_SUPPORTED
+ if (png_ptr != NULL && info_ptr != NULL &&
+ (info_ptr->valid & PNG_INFO_pHYs) != 0)
+ {
+ png_debug1(1, "in %s retrieval function", "png_get_pixels_per_meter");
+
+ if (info_ptr->phys_unit_type == PNG_RESOLUTION_METER &&
+ info_ptr->x_pixels_per_unit == info_ptr->y_pixels_per_unit)
+ return (info_ptr->x_pixels_per_unit);
+ }
+#else
+ PNG_UNUSED(png_ptr)
+ PNG_UNUSED(info_ptr)
+#endif
+
+ return (0);
+}
+
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+float PNGAPI
+png_get_pixel_aspect_ratio(png_const_structrp png_ptr, png_const_inforp
+ info_ptr)
+{
+#ifdef PNG_READ_pHYs_SUPPORTED
+ if (png_ptr != NULL && info_ptr != NULL &&
+ (info_ptr->valid & PNG_INFO_pHYs) != 0)
+ {
+ png_debug1(1, "in %s retrieval function", "png_get_aspect_ratio");
+
+ if (info_ptr->x_pixels_per_unit != 0)
+ return ((float)((float)info_ptr->y_pixels_per_unit
+ /(float)info_ptr->x_pixels_per_unit));
+ }
+#else
+ PNG_UNUSED(png_ptr)
+ PNG_UNUSED(info_ptr)
+#endif
+
+ return ((float)0.0);
+}
+#endif
+
+#ifdef PNG_FIXED_POINT_SUPPORTED
+png_fixed_point PNGAPI
+png_get_pixel_aspect_ratio_fixed(png_const_structrp png_ptr,
+ png_const_inforp info_ptr)
+{
+#ifdef PNG_READ_pHYs_SUPPORTED
+ if (png_ptr != NULL && info_ptr != NULL &&
+ (info_ptr->valid & PNG_INFO_pHYs) != 0 &&
+ info_ptr->x_pixels_per_unit > 0 && info_ptr->y_pixels_per_unit > 0 &&
+ info_ptr->x_pixels_per_unit <= PNG_UINT_31_MAX &&
+ info_ptr->y_pixels_per_unit <= PNG_UINT_31_MAX)
+ {
+ png_fixed_point res;
+
+ png_debug1(1, "in %s retrieval function", "png_get_aspect_ratio_fixed");
+
+ /* The following casts work because a PNG 4 byte integer only has a valid
+ * range of 0..2^31-1; otherwise the cast might overflow.
+ */
+ if (png_muldiv(&res, (png_int_32)info_ptr->y_pixels_per_unit, PNG_FP_1,
+ (png_int_32)info_ptr->x_pixels_per_unit) != 0)
+ return res;
+ }
+#else
+ PNG_UNUSED(png_ptr)
+ PNG_UNUSED(info_ptr)
+#endif
+
+ return 0;
+}
+#endif
+
+png_int_32 PNGAPI
+png_get_x_offset_microns(png_const_structrp png_ptr, png_const_inforp info_ptr)
+{
+#ifdef PNG_oFFs_SUPPORTED
+ if (png_ptr != NULL && info_ptr != NULL &&
+ (info_ptr->valid & PNG_INFO_oFFs) != 0)
+ {
+ png_debug1(1, "in %s retrieval function", "png_get_x_offset_microns");
+
+ if (info_ptr->offset_unit_type == PNG_OFFSET_MICROMETER)
+ return (info_ptr->x_offset);
+ }
+#else
+ PNG_UNUSED(png_ptr)
+ PNG_UNUSED(info_ptr)
+#endif
+
+ return (0);
+}
+
+png_int_32 PNGAPI
+png_get_y_offset_microns(png_const_structrp png_ptr, png_const_inforp info_ptr)
+{
+#ifdef PNG_oFFs_SUPPORTED
+ if (png_ptr != NULL && info_ptr != NULL &&
+ (info_ptr->valid & PNG_INFO_oFFs) != 0)
+ {
+ png_debug1(1, "in %s retrieval function", "png_get_y_offset_microns");
+
+ if (info_ptr->offset_unit_type == PNG_OFFSET_MICROMETER)
+ return (info_ptr->y_offset);
+ }
+#else
+ PNG_UNUSED(png_ptr)
+ PNG_UNUSED(info_ptr)
+#endif
+
+ return (0);
+}
+
+png_int_32 PNGAPI
+png_get_x_offset_pixels(png_const_structrp png_ptr, png_const_inforp info_ptr)
+{
+#ifdef PNG_oFFs_SUPPORTED
+ if (png_ptr != NULL && info_ptr != NULL &&
+ (info_ptr->valid & PNG_INFO_oFFs) != 0)
+ {
+ png_debug1(1, "in %s retrieval function", "png_get_x_offset_pixels");
+
+ if (info_ptr->offset_unit_type == PNG_OFFSET_PIXEL)
+ return (info_ptr->x_offset);
+ }
+#else
+ PNG_UNUSED(png_ptr)
+ PNG_UNUSED(info_ptr)
+#endif
+
+ return (0);
+}
+
+png_int_32 PNGAPI
+png_get_y_offset_pixels(png_const_structrp png_ptr, png_const_inforp info_ptr)
+{
+#ifdef PNG_oFFs_SUPPORTED
+ if (png_ptr != NULL && info_ptr != NULL &&
+ (info_ptr->valid & PNG_INFO_oFFs) != 0)
+ {
+ png_debug1(1, "in %s retrieval function", "png_get_y_offset_pixels");
+
+ if (info_ptr->offset_unit_type == PNG_OFFSET_PIXEL)
+ return (info_ptr->y_offset);
+ }
+#else
+ PNG_UNUSED(png_ptr)
+ PNG_UNUSED(info_ptr)
+#endif
+
+ return (0);
+}
+
+#ifdef PNG_INCH_CONVERSIONS_SUPPORTED
+static png_uint_32
+ppi_from_ppm(png_uint_32 ppm)
+{
+#if 0
+ /* The conversion is *(2.54/100), in binary (32 digits):
+ * .00000110100000001001110101001001
+ */
+ png_uint_32 t1001, t1101;
+ ppm >>= 1; /* .1 */
+ t1001 = ppm + (ppm >> 3); /* .1001 */
+ t1101 = t1001 + (ppm >> 1); /* .1101 */
+ ppm >>= 20; /* .000000000000000000001 */
+ t1101 += t1101 >> 15; /* .1101000000000001101 */
+ t1001 >>= 11; /* .000000000001001 */
+ t1001 += t1001 >> 12; /* .000000000001001000000001001 */
+ ppm += t1001; /* .000000000001001000001001001 */
+ ppm += t1101; /* .110100000001001110101001001 */
+ return (ppm + 16) >> 5;/* .00000110100000001001110101001001 */
+#else
+ /* The argument is a PNG unsigned integer, so it is not permitted
+ * to be bigger than 2^31.
+ */
+ png_fixed_point result;
+ if (ppm <= PNG_UINT_31_MAX && png_muldiv(&result, (png_int_32)ppm, 127,
+ 5000) != 0)
+ return result;
+
+ /* Overflow. */
+ return 0;
+#endif
+}
+
+png_uint_32 PNGAPI
+png_get_pixels_per_inch(png_const_structrp png_ptr, png_const_inforp info_ptr)
+{
+ return ppi_from_ppm(png_get_pixels_per_meter(png_ptr, info_ptr));
+}
+
+png_uint_32 PNGAPI
+png_get_x_pixels_per_inch(png_const_structrp png_ptr, png_const_inforp info_ptr)
+{
+ return ppi_from_ppm(png_get_x_pixels_per_meter(png_ptr, info_ptr));
+}
+
+png_uint_32 PNGAPI
+png_get_y_pixels_per_inch(png_const_structrp png_ptr, png_const_inforp info_ptr)
+{
+ return ppi_from_ppm(png_get_y_pixels_per_meter(png_ptr, info_ptr));
+}
+
+#ifdef PNG_FIXED_POINT_SUPPORTED
+static png_fixed_point
+png_fixed_inches_from_microns(png_const_structrp png_ptr, png_int_32 microns)
+{
+ /* Convert from metres * 1,000,000 to inches * 100,000, meters to
+ * inches is simply *(100/2.54), so we want *(10/2.54) == 500/127.
+ * Notice that this can overflow - a warning is output and 0 is
+ * returned.
+ */
+ return png_muldiv_warn(png_ptr, microns, 500, 127);
+}
+
+png_fixed_point PNGAPI
+png_get_x_offset_inches_fixed(png_const_structrp png_ptr,
+ png_const_inforp info_ptr)
+{
+ return png_fixed_inches_from_microns(png_ptr,
+ png_get_x_offset_microns(png_ptr, info_ptr));
+}
+#endif
+
+#ifdef PNG_FIXED_POINT_SUPPORTED
+png_fixed_point PNGAPI
+png_get_y_offset_inches_fixed(png_const_structrp png_ptr,
+ png_const_inforp info_ptr)
+{
+ return png_fixed_inches_from_microns(png_ptr,
+ png_get_y_offset_microns(png_ptr, info_ptr));
+}
+#endif
+
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+float PNGAPI
+png_get_x_offset_inches(png_const_structrp png_ptr, png_const_inforp info_ptr)
+{
+ /* To avoid the overflow do the conversion directly in floating
+ * point.
+ */
+ return (float)(png_get_x_offset_microns(png_ptr, info_ptr) * .00003937);
+}
+#endif
+
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+float PNGAPI
+png_get_y_offset_inches(png_const_structrp png_ptr, png_const_inforp info_ptr)
+{
+ /* To avoid the overflow do the conversion directly in floating
+ * point.
+ */
+ return (float)(png_get_y_offset_microns(png_ptr, info_ptr) * .00003937);
+}
+#endif
+
+#ifdef PNG_pHYs_SUPPORTED
+png_uint_32 PNGAPI
+png_get_pHYs_dpi(png_const_structrp png_ptr, png_const_inforp info_ptr,
+ png_uint_32 *res_x, png_uint_32 *res_y, int *unit_type)
+{
+ png_uint_32 retval = 0;
+
+ if (png_ptr != NULL && info_ptr != NULL &&
+ (info_ptr->valid & PNG_INFO_pHYs) != 0)
+ {
+ png_debug1(1, "in %s retrieval function", "pHYs");
+
+ if (res_x != NULL)
+ {
+ *res_x = info_ptr->x_pixels_per_unit;
+ retval |= PNG_INFO_pHYs;
+ }
+
+ if (res_y != NULL)
+ {
+ *res_y = info_ptr->y_pixels_per_unit;
+ retval |= PNG_INFO_pHYs;
+ }
+
+ if (unit_type != NULL)
+ {
+ *unit_type = (int)info_ptr->phys_unit_type;
+ retval |= PNG_INFO_pHYs;
+
+ if (*unit_type == 1)
+ {
+ if (res_x != NULL) *res_x = (png_uint_32)(*res_x * .0254 + .50);
+ if (res_y != NULL) *res_y = (png_uint_32)(*res_y * .0254 + .50);
+ }
+ }
+ }
+
+ return (retval);
+}
+#endif /* pHYs */
+#endif /* INCH_CONVERSIONS */
+
+/* png_get_channels really belongs in here, too, but it's been around longer */
+
+#endif /* EASY_ACCESS */
+
+
+png_byte PNGAPI
+png_get_channels(png_const_structrp png_ptr, png_const_inforp info_ptr)
+{
+ if (png_ptr != NULL && info_ptr != NULL)
+ return(info_ptr->channels);
+
+ return (0);
+}
+
+#ifdef PNG_READ_SUPPORTED
+png_const_bytep PNGAPI
+png_get_signature(png_const_structrp png_ptr, png_const_inforp info_ptr)
+{
+ if (png_ptr != NULL && info_ptr != NULL)
+ return(info_ptr->signature);
+
+ return (NULL);
+}
+#endif
+
+#ifdef PNG_bKGD_SUPPORTED
+png_uint_32 PNGAPI
+png_get_bKGD(png_const_structrp png_ptr, png_inforp info_ptr,
+ png_color_16p *background)
+{
+ if (png_ptr != NULL && info_ptr != NULL &&
+ (info_ptr->valid & PNG_INFO_bKGD) != 0 &&
+ background != NULL)
+ {
+ png_debug1(1, "in %s retrieval function", "bKGD");
+
+ *background = &(info_ptr->background);
+ return (PNG_INFO_bKGD);
+ }
+
+ return (0);
+}
+#endif
+
+#ifdef PNG_cHRM_SUPPORTED
+/* The XYZ APIs were added in 1.5.5 to take advantage of the code added at the
+ * same time to correct the rgb grayscale coefficient defaults obtained from the
+ * cHRM chunk in 1.5.4
+ */
+# ifdef PNG_FLOATING_POINT_SUPPORTED
+png_uint_32 PNGAPI
+png_get_cHRM(png_const_structrp png_ptr, png_const_inforp info_ptr,
+ double *white_x, double *white_y, double *red_x, double *red_y,
+ double *green_x, double *green_y, double *blue_x, double *blue_y)
+{
+ /* Quiet API change: this code used to only return the end points if a cHRM
+ * chunk was present, but the end points can also come from iCCP or sRGB
+ * chunks, so in 1.6.0 the png_get_ APIs return the end points regardless and
+ * the png_set_ APIs merely check that set end points are mutually
+ * consistent.
+ */
+ if (png_ptr != NULL && info_ptr != NULL &&
+ (info_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_ENDPOINTS) != 0)
+ {
+ png_debug1(1, "in %s retrieval function", "cHRM");
+
+ if (white_x != NULL)
+ *white_x = png_float(png_ptr,
+ info_ptr->colorspace.end_points_xy.whitex, "cHRM white X");
+ if (white_y != NULL)
+ *white_y = png_float(png_ptr,
+ info_ptr->colorspace.end_points_xy.whitey, "cHRM white Y");
+ if (red_x != NULL)
+ *red_x = png_float(png_ptr, info_ptr->colorspace.end_points_xy.redx,
+ "cHRM red X");
+ if (red_y != NULL)
+ *red_y = png_float(png_ptr, info_ptr->colorspace.end_points_xy.redy,
+ "cHRM red Y");
+ if (green_x != NULL)
+ *green_x = png_float(png_ptr,
+ info_ptr->colorspace.end_points_xy.greenx, "cHRM green X");
+ if (green_y != NULL)
+ *green_y = png_float(png_ptr,
+ info_ptr->colorspace.end_points_xy.greeny, "cHRM green Y");
+ if (blue_x != NULL)
+ *blue_x = png_float(png_ptr, info_ptr->colorspace.end_points_xy.bluex,
+ "cHRM blue X");
+ if (blue_y != NULL)
+ *blue_y = png_float(png_ptr, info_ptr->colorspace.end_points_xy.bluey,
+ "cHRM blue Y");
+ return (PNG_INFO_cHRM);
+ }
+
+ return (0);
+}
+
+png_uint_32 PNGAPI
+png_get_cHRM_XYZ(png_const_structrp png_ptr, png_const_inforp info_ptr,
+ double *red_X, double *red_Y, double *red_Z, double *green_X,
+ double *green_Y, double *green_Z, double *blue_X, double *blue_Y,
+ double *blue_Z)
+{
+ if (png_ptr != NULL && info_ptr != NULL &&
+ (info_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_ENDPOINTS) != 0)
+ {
+ png_debug1(1, "in %s retrieval function", "cHRM_XYZ(float)");
+
+ if (red_X != NULL)
+ *red_X = png_float(png_ptr, info_ptr->colorspace.end_points_XYZ.red_X,
+ "cHRM red X");
+ if (red_Y != NULL)
+ *red_Y = png_float(png_ptr, info_ptr->colorspace.end_points_XYZ.red_Y,
+ "cHRM red Y");
+ if (red_Z != NULL)
+ *red_Z = png_float(png_ptr, info_ptr->colorspace.end_points_XYZ.red_Z,
+ "cHRM red Z");
+ if (green_X != NULL)
+ *green_X = png_float(png_ptr,
+ info_ptr->colorspace.end_points_XYZ.green_X, "cHRM green X");
+ if (green_Y != NULL)
+ *green_Y = png_float(png_ptr,
+ info_ptr->colorspace.end_points_XYZ.green_Y, "cHRM green Y");
+ if (green_Z != NULL)
+ *green_Z = png_float(png_ptr,
+ info_ptr->colorspace.end_points_XYZ.green_Z, "cHRM green Z");
+ if (blue_X != NULL)
+ *blue_X = png_float(png_ptr,
+ info_ptr->colorspace.end_points_XYZ.blue_X, "cHRM blue X");
+ if (blue_Y != NULL)
+ *blue_Y = png_float(png_ptr,
+ info_ptr->colorspace.end_points_XYZ.blue_Y, "cHRM blue Y");
+ if (blue_Z != NULL)
+ *blue_Z = png_float(png_ptr,
+ info_ptr->colorspace.end_points_XYZ.blue_Z, "cHRM blue Z");
+ return (PNG_INFO_cHRM);
+ }
+
+ return (0);
+}
+# endif
+
+# ifdef PNG_FIXED_POINT_SUPPORTED
+png_uint_32 PNGAPI
+png_get_cHRM_XYZ_fixed(png_const_structrp png_ptr, png_const_inforp info_ptr,
+ png_fixed_point *int_red_X, png_fixed_point *int_red_Y,
+ png_fixed_point *int_red_Z, png_fixed_point *int_green_X,
+ png_fixed_point *int_green_Y, png_fixed_point *int_green_Z,
+ png_fixed_point *int_blue_X, png_fixed_point *int_blue_Y,
+ png_fixed_point *int_blue_Z)
+{
+ if (png_ptr != NULL && info_ptr != NULL &&
+ (info_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_ENDPOINTS) != 0)
+ {
+ png_debug1(1, "in %s retrieval function", "cHRM_XYZ");
+
+ if (int_red_X != NULL)
+ *int_red_X = info_ptr->colorspace.end_points_XYZ.red_X;
+ if (int_red_Y != NULL)
+ *int_red_Y = info_ptr->colorspace.end_points_XYZ.red_Y;
+ if (int_red_Z != NULL)
+ *int_red_Z = info_ptr->colorspace.end_points_XYZ.red_Z;
+ if (int_green_X != NULL)
+ *int_green_X = info_ptr->colorspace.end_points_XYZ.green_X;
+ if (int_green_Y != NULL)
+ *int_green_Y = info_ptr->colorspace.end_points_XYZ.green_Y;
+ if (int_green_Z != NULL)
+ *int_green_Z = info_ptr->colorspace.end_points_XYZ.green_Z;
+ if (int_blue_X != NULL)
+ *int_blue_X = info_ptr->colorspace.end_points_XYZ.blue_X;
+ if (int_blue_Y != NULL)
+ *int_blue_Y = info_ptr->colorspace.end_points_XYZ.blue_Y;
+ if (int_blue_Z != NULL)
+ *int_blue_Z = info_ptr->colorspace.end_points_XYZ.blue_Z;
+ return (PNG_INFO_cHRM);
+ }
+
+ return (0);
+}
+
+png_uint_32 PNGAPI
+png_get_cHRM_fixed(png_const_structrp png_ptr, png_const_inforp info_ptr,
+ png_fixed_point *white_x, png_fixed_point *white_y, png_fixed_point *red_x,
+ png_fixed_point *red_y, png_fixed_point *green_x, png_fixed_point *green_y,
+ png_fixed_point *blue_x, png_fixed_point *blue_y)
+{
+ png_debug1(1, "in %s retrieval function", "cHRM");
+
+ if (png_ptr != NULL && info_ptr != NULL &&
+ (info_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_ENDPOINTS) != 0)
+ {
+ if (white_x != NULL)
+ *white_x = info_ptr->colorspace.end_points_xy.whitex;
+ if (white_y != NULL)
+ *white_y = info_ptr->colorspace.end_points_xy.whitey;
+ if (red_x != NULL)
+ *red_x = info_ptr->colorspace.end_points_xy.redx;
+ if (red_y != NULL)
+ *red_y = info_ptr->colorspace.end_points_xy.redy;
+ if (green_x != NULL)
+ *green_x = info_ptr->colorspace.end_points_xy.greenx;
+ if (green_y != NULL)
+ *green_y = info_ptr->colorspace.end_points_xy.greeny;
+ if (blue_x != NULL)
+ *blue_x = info_ptr->colorspace.end_points_xy.bluex;
+ if (blue_y != NULL)
+ *blue_y = info_ptr->colorspace.end_points_xy.bluey;
+ return (PNG_INFO_cHRM);
+ }
+
+ return (0);
+}
+# endif
+#endif
+
+#ifdef PNG_gAMA_SUPPORTED
+# ifdef PNG_FIXED_POINT_SUPPORTED
+png_uint_32 PNGAPI
+png_get_gAMA_fixed(png_const_structrp png_ptr, png_const_inforp info_ptr,
+ png_fixed_point *file_gamma)
+{
+ png_debug1(1, "in %s retrieval function", "gAMA");
+
+ if (png_ptr != NULL && info_ptr != NULL &&
+ (info_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_GAMMA) != 0 &&
+ file_gamma != NULL)
+ {
+ *file_gamma = info_ptr->colorspace.gamma;
+ return (PNG_INFO_gAMA);
+ }
+
+ return (0);
+}
+# endif
+
+# ifdef PNG_FLOATING_POINT_SUPPORTED
+png_uint_32 PNGAPI
+png_get_gAMA(png_const_structrp png_ptr, png_const_inforp info_ptr,
+ double *file_gamma)
+{
+ png_debug1(1, "in %s retrieval function", "gAMA(float)");
+
+ if (png_ptr != NULL && info_ptr != NULL &&
+ (info_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_GAMMA) != 0 &&
+ file_gamma != NULL)
+ {
+ *file_gamma = png_float(png_ptr, info_ptr->colorspace.gamma,
+ "png_get_gAMA");
+ return (PNG_INFO_gAMA);
+ }
+
+ return (0);
+}
+# endif
+#endif
+
+#ifdef PNG_sRGB_SUPPORTED
+png_uint_32 PNGAPI
+png_get_sRGB(png_const_structrp png_ptr, png_const_inforp info_ptr,
+ int *file_srgb_intent)
+{
+ png_debug1(1, "in %s retrieval function", "sRGB");
+
+ if (png_ptr != NULL && info_ptr != NULL &&
+ (info_ptr->valid & PNG_INFO_sRGB) != 0 && file_srgb_intent != NULL)
+ {
+ *file_srgb_intent = info_ptr->colorspace.rendering_intent;
+ return (PNG_INFO_sRGB);
+ }
+
+ return (0);
+}
+#endif
+
+#ifdef PNG_iCCP_SUPPORTED
+png_uint_32 PNGAPI
+png_get_iCCP(png_const_structrp png_ptr, png_inforp info_ptr,
+ png_charpp name, int *compression_type,
+ png_bytepp profile, png_uint_32 *proflen)
+{
+ png_debug1(1, "in %s retrieval function", "iCCP");
+
+ if (png_ptr != NULL && info_ptr != NULL &&
+ (info_ptr->valid & PNG_INFO_iCCP) != 0 &&
+ name != NULL && compression_type != NULL && profile != NULL &&
+ proflen != NULL)
+ {
+ *name = info_ptr->iccp_name;
+ *profile = info_ptr->iccp_profile;
+ *proflen = png_get_uint_32(info_ptr->iccp_profile);
+ /* This is somewhat irrelevant since the profile data returned has
+ * actually been uncompressed.
+ */
+ *compression_type = PNG_COMPRESSION_TYPE_BASE;
+ return (PNG_INFO_iCCP);
+ }
+
+ return (0);
+}
+#endif
+
+#ifdef PNG_sPLT_SUPPORTED
+int PNGAPI
+png_get_sPLT(png_const_structrp png_ptr, png_inforp info_ptr,
+ png_sPLT_tpp spalettes)
+{
+ if (png_ptr != NULL && info_ptr != NULL && spalettes != NULL)
+ {
+ *spalettes = info_ptr->splt_palettes;
+ return info_ptr->splt_palettes_num;
+ }
+
+ return (0);
+}
+#endif
+
+#ifdef PNG_hIST_SUPPORTED
+png_uint_32 PNGAPI
+png_get_hIST(png_const_structrp png_ptr, png_inforp info_ptr,
+ png_uint_16p *hist)
+{
+ png_debug1(1, "in %s retrieval function", "hIST");
+
+ if (png_ptr != NULL && info_ptr != NULL &&
+ (info_ptr->valid & PNG_INFO_hIST) != 0 && hist != NULL)
+ {
+ *hist = info_ptr->hist;
+ return (PNG_INFO_hIST);
+ }
+
+ return (0);
+}
+#endif
+
+png_uint_32 PNGAPI
+png_get_IHDR(png_const_structrp png_ptr, png_const_inforp info_ptr,
+ png_uint_32 *width, png_uint_32 *height, int *bit_depth,
+ int *color_type, int *interlace_type, int *compression_type,
+ int *filter_type)
+{
+ png_debug1(1, "in %s retrieval function", "IHDR");
+
+ if (png_ptr == NULL || info_ptr == NULL)
+ return (0);
+
+ if (width != NULL)
+ *width = info_ptr->width;
+
+ if (height != NULL)
+ *height = info_ptr->height;
+
+ if (bit_depth != NULL)
+ *bit_depth = info_ptr->bit_depth;
+
+ if (color_type != NULL)
+ *color_type = info_ptr->color_type;
+
+ if (compression_type != NULL)
+ *compression_type = info_ptr->compression_type;
+
+ if (filter_type != NULL)
+ *filter_type = info_ptr->filter_type;
+
+ if (interlace_type != NULL)
+ *interlace_type = info_ptr->interlace_type;
+
+ /* This is redundant if we can be sure that the info_ptr values were all
+ * assigned in png_set_IHDR(). We do the check anyhow in case an
+ * application has ignored our advice not to mess with the members
+ * of info_ptr directly.
+ */
+ png_check_IHDR(png_ptr, info_ptr->width, info_ptr->height,
+ info_ptr->bit_depth, info_ptr->color_type, info_ptr->interlace_type,
+ info_ptr->compression_type, info_ptr->filter_type);
+
+ return (1);
+}
+
+#ifdef PNG_oFFs_SUPPORTED
+png_uint_32 PNGAPI
+png_get_oFFs(png_const_structrp png_ptr, png_const_inforp info_ptr,
+ png_int_32 *offset_x, png_int_32 *offset_y, int *unit_type)
+{
+ png_debug1(1, "in %s retrieval function", "oFFs");
+
+ if (png_ptr != NULL && info_ptr != NULL &&
+ (info_ptr->valid & PNG_INFO_oFFs) != 0 &&
+ offset_x != NULL && offset_y != NULL && unit_type != NULL)
+ {
+ *offset_x = info_ptr->x_offset;
+ *offset_y = info_ptr->y_offset;
+ *unit_type = (int)info_ptr->offset_unit_type;
+ return (PNG_INFO_oFFs);
+ }
+
+ return (0);
+}
+#endif
+
+#ifdef PNG_pCAL_SUPPORTED
+png_uint_32 PNGAPI
+png_get_pCAL(png_const_structrp png_ptr, png_inforp info_ptr,
+ png_charp *purpose, png_int_32 *X0, png_int_32 *X1, int *type, int *nparams,
+ png_charp *units, png_charpp *params)
+{
+ png_debug1(1, "in %s retrieval function", "pCAL");
+
+ if (png_ptr != NULL && info_ptr != NULL &&
+ (info_ptr->valid & PNG_INFO_pCAL) != 0 &&
+ purpose != NULL && X0 != NULL && X1 != NULL && type != NULL &&
+ nparams != NULL && units != NULL && params != NULL)
+ {
+ *purpose = info_ptr->pcal_purpose;
+ *X0 = info_ptr->pcal_X0;
+ *X1 = info_ptr->pcal_X1;
+ *type = (int)info_ptr->pcal_type;
+ *nparams = (int)info_ptr->pcal_nparams;
+ *units = info_ptr->pcal_units;
+ *params = info_ptr->pcal_params;
+ return (PNG_INFO_pCAL);
+ }
+
+ return (0);
+}
+#endif
+
+#ifdef PNG_sCAL_SUPPORTED
+# ifdef PNG_FIXED_POINT_SUPPORTED
+# if defined(PNG_FLOATING_ARITHMETIC_SUPPORTED) || \
+ defined(PNG_FLOATING_POINT_SUPPORTED)
+png_uint_32 PNGAPI
+png_get_sCAL_fixed(png_const_structrp png_ptr, png_const_inforp info_ptr,
+ int *unit, png_fixed_point *width, png_fixed_point *height)
+{
+ if (png_ptr != NULL && info_ptr != NULL &&
+ (info_ptr->valid & PNG_INFO_sCAL) != 0)
+ {
+ *unit = info_ptr->scal_unit;
+ /*TODO: make this work without FP support; the API is currently eliminated
+ * if neither floating point APIs nor internal floating point arithmetic
+ * are enabled.
+ */
+ *width = png_fixed(png_ptr, atof(info_ptr->scal_s_width), "sCAL width");
+ *height = png_fixed(png_ptr, atof(info_ptr->scal_s_height),
+ "sCAL height");
+ return (PNG_INFO_sCAL);
+ }
+
+ return(0);
+}
+# endif /* FLOATING_ARITHMETIC */
+# endif /* FIXED_POINT */
+# ifdef PNG_FLOATING_POINT_SUPPORTED
+png_uint_32 PNGAPI
+png_get_sCAL(png_const_structrp png_ptr, png_const_inforp info_ptr,
+ int *unit, double *width, double *height)
+{
+ if (png_ptr != NULL && info_ptr != NULL &&
+ (info_ptr->valid & PNG_INFO_sCAL) != 0)
+ {
+ *unit = info_ptr->scal_unit;
+ *width = atof(info_ptr->scal_s_width);
+ *height = atof(info_ptr->scal_s_height);
+ return (PNG_INFO_sCAL);
+ }
+
+ return(0);
+}
+# endif /* FLOATING POINT */
+png_uint_32 PNGAPI
+png_get_sCAL_s(png_const_structrp png_ptr, png_const_inforp info_ptr,
+ int *unit, png_charpp width, png_charpp height)
+{
+ if (png_ptr != NULL && info_ptr != NULL &&
+ (info_ptr->valid & PNG_INFO_sCAL) != 0)
+ {
+ *unit = info_ptr->scal_unit;
+ *width = info_ptr->scal_s_width;
+ *height = info_ptr->scal_s_height;
+ return (PNG_INFO_sCAL);
+ }
+
+ return(0);
+}
+#endif /* sCAL */
+
+#ifdef PNG_pHYs_SUPPORTED
+png_uint_32 PNGAPI
+png_get_pHYs(png_const_structrp png_ptr, png_const_inforp info_ptr,
+ png_uint_32 *res_x, png_uint_32 *res_y, int *unit_type)
+{
+ png_uint_32 retval = 0;
+
+ png_debug1(1, "in %s retrieval function", "pHYs");
+
+ if (png_ptr != NULL && info_ptr != NULL &&
+ (info_ptr->valid & PNG_INFO_pHYs) != 0)
+ {
+ if (res_x != NULL)
+ {
+ *res_x = info_ptr->x_pixels_per_unit;
+ retval |= PNG_INFO_pHYs;
+ }
+
+ if (res_y != NULL)
+ {
+ *res_y = info_ptr->y_pixels_per_unit;
+ retval |= PNG_INFO_pHYs;
+ }
+
+ if (unit_type != NULL)
+ {
+ *unit_type = (int)info_ptr->phys_unit_type;
+ retval |= PNG_INFO_pHYs;
+ }
+ }
+
+ return (retval);
+}
+#endif /* pHYs */
+
+png_uint_32 PNGAPI
+png_get_PLTE(png_const_structrp png_ptr, png_inforp info_ptr,
+ png_colorp *palette, int *num_palette)
+{
+ png_debug1(1, "in %s retrieval function", "PLTE");
+
+ if (png_ptr != NULL && info_ptr != NULL &&
+ (info_ptr->valid & PNG_INFO_PLTE) != 0 && palette != NULL)
+ {
+ *palette = info_ptr->palette;
+ *num_palette = info_ptr->num_palette;
+ png_debug1(3, "num_palette = %d", *num_palette);
+ return (PNG_INFO_PLTE);
+ }
+
+ return (0);
+}
+
+#ifdef PNG_sBIT_SUPPORTED
+png_uint_32 PNGAPI
+png_get_sBIT(png_const_structrp png_ptr, png_inforp info_ptr,
+ png_color_8p *sig_bit)
+{
+ png_debug1(1, "in %s retrieval function", "sBIT");
+
+ if (png_ptr != NULL && info_ptr != NULL &&
+ (info_ptr->valid & PNG_INFO_sBIT) != 0 && sig_bit != NULL)
+ {
+ *sig_bit = &(info_ptr->sig_bit);
+ return (PNG_INFO_sBIT);
+ }
+
+ return (0);
+}
+#endif
+
+#ifdef PNG_TEXT_SUPPORTED
+int PNGAPI
+png_get_text(png_const_structrp png_ptr, png_inforp info_ptr,
+ png_textp *text_ptr, int *num_text)
+{
+ if (png_ptr != NULL && info_ptr != NULL && info_ptr->num_text > 0)
+ {
+ png_debug1(1, "in 0x%lx retrieval function",
+ (unsigned long)png_ptr->chunk_name);
+
+ if (text_ptr != NULL)
+ *text_ptr = info_ptr->text;
+
+ if (num_text != NULL)
+ *num_text = info_ptr->num_text;
+
+ return info_ptr->num_text;
+ }
+
+ if (num_text != NULL)
+ *num_text = 0;
+
+ return(0);
+}
+#endif
+
+#ifdef PNG_tIME_SUPPORTED
+png_uint_32 PNGAPI
+png_get_tIME(png_const_structrp png_ptr, png_inforp info_ptr,
+ png_timep *mod_time)
+{
+ png_debug1(1, "in %s retrieval function", "tIME");
+
+ if (png_ptr != NULL && info_ptr != NULL &&
+ (info_ptr->valid & PNG_INFO_tIME) != 0 && mod_time != NULL)
+ {
+ *mod_time = &(info_ptr->mod_time);
+ return (PNG_INFO_tIME);
+ }
+
+ return (0);
+}
+#endif
+
+#ifdef PNG_tRNS_SUPPORTED
+png_uint_32 PNGAPI
+png_get_tRNS(png_const_structrp png_ptr, png_inforp info_ptr,
+ png_bytep *trans_alpha, int *num_trans, png_color_16p *trans_color)
+{
+ png_uint_32 retval = 0;
+ if (png_ptr != NULL && info_ptr != NULL &&
+ (info_ptr->valid & PNG_INFO_tRNS) != 0)
+ {
+ png_debug1(1, "in %s retrieval function", "tRNS");
+
+ if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
+ {
+ if (trans_alpha != NULL)
+ {
+ *trans_alpha = info_ptr->trans_alpha;
+ retval |= PNG_INFO_tRNS;
+ }
+
+ if (trans_color != NULL)
+ *trans_color = &(info_ptr->trans_color);
+ }
+
+ else /* if (info_ptr->color_type != PNG_COLOR_TYPE_PALETTE) */
+ {
+ if (trans_color != NULL)
+ {
+ *trans_color = &(info_ptr->trans_color);
+ retval |= PNG_INFO_tRNS;
+ }
+
+ if (trans_alpha != NULL)
+ *trans_alpha = NULL;
+ }
+
+ if (num_trans != NULL)
+ {
+ *num_trans = info_ptr->num_trans;
+ retval |= PNG_INFO_tRNS;
+ }
+ }
+
+ return (retval);
+}
+#endif
+
+#ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED
+int PNGAPI
+png_get_unknown_chunks(png_const_structrp png_ptr, png_inforp info_ptr,
+ png_unknown_chunkpp unknowns)
+{
+ if (png_ptr != NULL && info_ptr != NULL && unknowns != NULL)
+ {
+ *unknowns = info_ptr->unknown_chunks;
+ return info_ptr->unknown_chunks_num;
+ }
+
+ return (0);
+}
+#endif
+
+#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
+png_byte PNGAPI
+png_get_rgb_to_gray_status (png_const_structrp png_ptr)
+{
+ return (png_byte)(png_ptr ? png_ptr->rgb_to_gray_status : 0);
+}
+#endif
+
+#ifdef PNG_USER_CHUNKS_SUPPORTED
+png_voidp PNGAPI
+png_get_user_chunk_ptr(png_const_structrp png_ptr)
+{
+ return (png_ptr ? png_ptr->user_chunk_ptr : NULL);
+}
+#endif
+
+png_size_t PNGAPI
+png_get_compression_buffer_size(png_const_structrp png_ptr)
+{
+ if (png_ptr == NULL)
+ return 0;
+
+#ifdef PNG_WRITE_SUPPORTED
+ if ((png_ptr->mode & PNG_IS_READ_STRUCT) != 0)
+#endif
+ {
+#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
+ return png_ptr->IDAT_read_size;
+#else
+ return PNG_IDAT_READ_SIZE;
+#endif
+ }
+
+#ifdef PNG_WRITE_SUPPORTED
+ else
+ return png_ptr->zbuffer_size;
+#endif
+}
+
+#ifdef PNG_SET_USER_LIMITS_SUPPORTED
+/* These functions were added to libpng 1.2.6 and were enabled
+ * by default in libpng-1.4.0 */
+png_uint_32 PNGAPI
+png_get_user_width_max (png_const_structrp png_ptr)
+{
+ return (png_ptr ? png_ptr->user_width_max : 0);
+}
+
+png_uint_32 PNGAPI
+png_get_user_height_max (png_const_structrp png_ptr)
+{
+ return (png_ptr ? png_ptr->user_height_max : 0);
+}
+
+/* This function was added to libpng 1.4.0 */
+png_uint_32 PNGAPI
+png_get_chunk_cache_max (png_const_structrp png_ptr)
+{
+ return (png_ptr ? png_ptr->user_chunk_cache_max : 0);
+}
+
+/* This function was added to libpng 1.4.1 */
+png_alloc_size_t PNGAPI
+png_get_chunk_malloc_max (png_const_structrp png_ptr)
+{
+ return (png_ptr ? png_ptr->user_chunk_malloc_max : 0);
+}
+#endif /* SET_USER_LIMITS */
+
+/* These functions were added to libpng 1.4.0 */
+#ifdef PNG_IO_STATE_SUPPORTED
+png_uint_32 PNGAPI
+png_get_io_state (png_const_structrp png_ptr)
+{
+ return png_ptr->io_state;
+}
+
+png_uint_32 PNGAPI
+png_get_io_chunk_type (png_const_structrp png_ptr)
+{
+ return png_ptr->chunk_name;
+}
+#endif /* IO_STATE */
+
+#ifdef PNG_CHECK_FOR_INVALID_INDEX_SUPPORTED
+# ifdef PNG_GET_PALETTE_MAX_SUPPORTED
+int PNGAPI
+png_get_palette_max(png_const_structp png_ptr, png_const_infop info_ptr)
+{
+ if (png_ptr != NULL && info_ptr != NULL)
+ return png_ptr->num_palette_max;
+
+ return (-1);
+}
+# endif
+#endif
+
+#endif /* READ || WRITE */
--- /dev/null
+
+/* pnginfo.h - header file for PNG reference library
+ *
+ * Last changed in libpng 1.6.1 [March 28, 2013]
+ * Copyright (c) 1998-2013 Glenn Randers-Pehrson
+ * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
+ * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ */
+
+ /* png_info is a structure that holds the information in a PNG file so
+ * that the application can find out the characteristics of the image.
+ * If you are reading the file, this structure will tell you what is
+ * in the PNG file. If you are writing the file, fill in the information
+ * you want to put into the PNG file, using png_set_*() functions, then
+ * call png_write_info().
+ *
+ * The names chosen should be very close to the PNG specification, so
+ * consult that document for information about the meaning of each field.
+ *
+ * With libpng < 0.95, it was only possible to directly set and read the
+ * the values in the png_info_struct, which meant that the contents and
+ * order of the values had to remain fixed. With libpng 0.95 and later,
+ * however, there are now functions that abstract the contents of
+ * png_info_struct from the application, so this makes it easier to use
+ * libpng with dynamic libraries, and even makes it possible to use
+ * libraries that don't have all of the libpng ancillary chunk-handing
+ * functionality. In libpng-1.5.0 this was moved into a separate private
+ * file that is not visible to applications.
+ *
+ * The following members may have allocated storage attached that should be
+ * cleaned up before the structure is discarded: palette, trans, text,
+ * pcal_purpose, pcal_units, pcal_params, hist, iccp_name, iccp_profile,
+ * splt_palettes, scal_unit, row_pointers, and unknowns. By default, these
+ * are automatically freed when the info structure is deallocated, if they were
+ * allocated internally by libpng. This behavior can be changed by means
+ * of the png_data_freer() function.
+ *
+ * More allocation details: all the chunk-reading functions that
+ * change these members go through the corresponding png_set_*
+ * functions. A function to clear these members is available: see
+ * png_free_data(). The png_set_* functions do not depend on being
+ * able to point info structure members to any of the storage they are
+ * passed (they make their own copies), EXCEPT that the png_set_text
+ * functions use the same storage passed to them in the text_ptr or
+ * itxt_ptr structure argument, and the png_set_rows and png_set_unknowns
+ * functions do not make their own copies.
+ */
+#ifndef PNGINFO_H
+#define PNGINFO_H
+
+struct png_info_def
+{
+ /* The following are necessary for every PNG file */
+ png_uint_32 width; /* width of image in pixels (from IHDR) */
+ png_uint_32 height; /* height of image in pixels (from IHDR) */
+ png_uint_32 valid; /* valid chunk data (see PNG_INFO_ below) */
+ png_size_t rowbytes; /* bytes needed to hold an untransformed row */
+ png_colorp palette; /* array of color values (valid & PNG_INFO_PLTE) */
+ png_uint_16 num_palette; /* number of color entries in "palette" (PLTE) */
+ png_uint_16 num_trans; /* number of transparent palette color (tRNS) */
+ png_byte bit_depth; /* 1, 2, 4, 8, or 16 bits/channel (from IHDR) */
+ png_byte color_type; /* see PNG_COLOR_TYPE_ below (from IHDR) */
+ /* The following three should have been named *_method not *_type */
+ png_byte compression_type; /* must be PNG_COMPRESSION_TYPE_BASE (IHDR) */
+ png_byte filter_type; /* must be PNG_FILTER_TYPE_BASE (from IHDR) */
+ png_byte interlace_type; /* One of PNG_INTERLACE_NONE, PNG_INTERLACE_ADAM7 */
+
+ /* The following are set by png_set_IHDR, called from the application on
+ * write, but the are never actually used by the write code.
+ */
+ png_byte channels; /* number of data channels per pixel (1, 2, 3, 4) */
+ png_byte pixel_depth; /* number of bits per pixel */
+ png_byte spare_byte; /* to align the data, and for future use */
+
+#ifdef PNG_READ_SUPPORTED
+ /* This is never set during write */
+ png_byte signature[8]; /* magic bytes read by libpng from start of file */
+#endif
+
+ /* The rest of the data is optional. If you are reading, check the
+ * valid field to see if the information in these are valid. If you
+ * are writing, set the valid field to those chunks you want written,
+ * and initialize the appropriate fields below.
+ */
+
+#if defined(PNG_COLORSPACE_SUPPORTED) || defined(PNG_GAMMA_SUPPORTED)
+ /* png_colorspace only contains 'flags' if neither GAMMA or COLORSPACE are
+ * defined. When COLORSPACE is switched on all the colorspace-defining
+ * chunks should be enabled, when GAMMA is switched on all the gamma-defining
+ * chunks should be enabled. If this is not done it becomes possible to read
+ * inconsistent PNG files and assign a probably incorrect interpretation to
+ * the information. (In other words, by carefully choosing which chunks to
+ * recognize the system configuration can select an interpretation for PNG
+ * files containing ambiguous data and this will result in inconsistent
+ * behavior between different libpng builds!)
+ */
+ png_colorspace colorspace;
+#endif
+
+#ifdef PNG_iCCP_SUPPORTED
+ /* iCCP chunk data. */
+ png_charp iccp_name; /* profile name */
+ png_bytep iccp_profile; /* International Color Consortium profile data */
+ png_uint_32 iccp_proflen; /* ICC profile data length */
+#endif
+
+#ifdef PNG_TEXT_SUPPORTED
+ /* The tEXt, and zTXt chunks contain human-readable textual data in
+ * uncompressed, compressed, and optionally compressed forms, respectively.
+ * The data in "text" is an array of pointers to uncompressed,
+ * null-terminated C strings. Each chunk has a keyword that describes the
+ * textual data contained in that chunk. Keywords are not required to be
+ * unique, and the text string may be empty. Any number of text chunks may
+ * be in an image.
+ */
+ int num_text; /* number of comments read or comments to write */
+ int max_text; /* current size of text array */
+ png_textp text; /* array of comments read or comments to write */
+#endif /* TEXT */
+
+#ifdef PNG_tIME_SUPPORTED
+ /* The tIME chunk holds the last time the displayed image data was
+ * modified. See the png_time struct for the contents of this struct.
+ */
+ png_time mod_time;
+#endif
+
+#ifdef PNG_sBIT_SUPPORTED
+ /* The sBIT chunk specifies the number of significant high-order bits
+ * in the pixel data. Values are in the range [1, bit_depth], and are
+ * only specified for the channels in the pixel data. The contents of
+ * the low-order bits is not specified. Data is valid if
+ * (valid & PNG_INFO_sBIT) is non-zero.
+ */
+ png_color_8 sig_bit; /* significant bits in color channels */
+#endif
+
+#if defined(PNG_tRNS_SUPPORTED) || defined(PNG_READ_EXPAND_SUPPORTED) || \
+defined(PNG_READ_BACKGROUND_SUPPORTED)
+ /* The tRNS chunk supplies transparency data for paletted images and
+ * other image types that don't need a full alpha channel. There are
+ * "num_trans" transparency values for a paletted image, stored in the
+ * same order as the palette colors, starting from index 0. Values
+ * for the data are in the range [0, 255], ranging from fully transparent
+ * to fully opaque, respectively. For non-paletted images, there is a
+ * single color specified that should be treated as fully transparent.
+ * Data is valid if (valid & PNG_INFO_tRNS) is non-zero.
+ */
+ png_bytep trans_alpha; /* alpha values for paletted image */
+ png_color_16 trans_color; /* transparent color for non-palette image */
+#endif
+
+#if defined(PNG_bKGD_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
+ /* The bKGD chunk gives the suggested image background color if the
+ * display program does not have its own background color and the image
+ * is needs to composited onto a background before display. The colors
+ * in "background" are normally in the same color space/depth as the
+ * pixel data. Data is valid if (valid & PNG_INFO_bKGD) is non-zero.
+ */
+ png_color_16 background;
+#endif
+
+#ifdef PNG_oFFs_SUPPORTED
+ /* The oFFs chunk gives the offset in "offset_unit_type" units rightwards
+ * and downwards from the top-left corner of the display, page, or other
+ * application-specific co-ordinate space. See the PNG_OFFSET_ defines
+ * below for the unit types. Valid if (valid & PNG_INFO_oFFs) non-zero.
+ */
+ png_int_32 x_offset; /* x offset on page */
+ png_int_32 y_offset; /* y offset on page */
+ png_byte offset_unit_type; /* offset units type */
+#endif
+
+#ifdef PNG_pHYs_SUPPORTED
+ /* The pHYs chunk gives the physical pixel density of the image for
+ * display or printing in "phys_unit_type" units (see PNG_RESOLUTION_
+ * defines below). Data is valid if (valid & PNG_INFO_pHYs) is non-zero.
+ */
+ png_uint_32 x_pixels_per_unit; /* horizontal pixel density */
+ png_uint_32 y_pixels_per_unit; /* vertical pixel density */
+ png_byte phys_unit_type; /* resolution type (see PNG_RESOLUTION_ below) */
+#endif
+
+#ifdef PNG_hIST_SUPPORTED
+ /* The hIST chunk contains the relative frequency or importance of the
+ * various palette entries, so that a viewer can intelligently select a
+ * reduced-color palette, if required. Data is an array of "num_palette"
+ * values in the range [0,65535]. Data valid if (valid & PNG_INFO_hIST)
+ * is non-zero.
+ */
+ png_uint_16p hist;
+#endif
+
+#ifdef PNG_pCAL_SUPPORTED
+ /* The pCAL chunk describes a transformation between the stored pixel
+ * values and original physical data values used to create the image.
+ * The integer range [0, 2^bit_depth - 1] maps to the floating-point
+ * range given by [pcal_X0, pcal_X1], and are further transformed by a
+ * (possibly non-linear) transformation function given by "pcal_type"
+ * and "pcal_params" into "pcal_units". Please see the PNG_EQUATION_
+ * defines below, and the PNG-Group's PNG extensions document for a
+ * complete description of the transformations and how they should be
+ * implemented, and for a description of the ASCII parameter strings.
+ * Data values are valid if (valid & PNG_INFO_pCAL) non-zero.
+ */
+ png_charp pcal_purpose; /* pCAL chunk description string */
+ png_int_32 pcal_X0; /* minimum value */
+ png_int_32 pcal_X1; /* maximum value */
+ png_charp pcal_units; /* Latin-1 string giving physical units */
+ png_charpp pcal_params; /* ASCII strings containing parameter values */
+ png_byte pcal_type; /* equation type (see PNG_EQUATION_ below) */
+ png_byte pcal_nparams; /* number of parameters given in pcal_params */
+#endif
+
+/* New members added in libpng-1.0.6 */
+ png_uint_32 free_me; /* flags items libpng is responsible for freeing */
+
+#ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED
+ /* Storage for unknown chunks that the library doesn't recognize. */
+ png_unknown_chunkp unknown_chunks;
+
+ /* The type of this field is limited by the type of
+ * png_struct::user_chunk_cache_max, else overflow can occur.
+ */
+ int unknown_chunks_num;
+#endif
+
+#ifdef PNG_sPLT_SUPPORTED
+ /* Data on sPLT chunks (there may be more than one). */
+ png_sPLT_tp splt_palettes;
+ int splt_palettes_num; /* Match type returned by png_get API */
+#endif
+
+#ifdef PNG_sCAL_SUPPORTED
+ /* The sCAL chunk describes the actual physical dimensions of the
+ * subject matter of the graphic. The chunk contains a unit specification
+ * a byte value, and two ASCII strings representing floating-point
+ * values. The values are width and height corresponsing to one pixel
+ * in the image. Data values are valid if (valid & PNG_INFO_sCAL) is
+ * non-zero.
+ */
+ png_byte scal_unit; /* unit of physical scale */
+ png_charp scal_s_width; /* string containing height */
+ png_charp scal_s_height; /* string containing width */
+#endif
+
+#ifdef PNG_INFO_IMAGE_SUPPORTED
+ /* Memory has been allocated if (valid & PNG_ALLOCATED_INFO_ROWS)
+ non-zero */
+ /* Data valid if (valid & PNG_INFO_IDAT) non-zero */
+ png_bytepp row_pointers; /* the image bits */
+#endif
+
+};
+#endif /* PNGINFO_H */
--- /dev/null
+/* libpng 1.6.17 STANDARD API DEFINITION */
+
+/* pnglibconf.h - library build configuration */
+
+/* Libpng version 1.6.17 - March 26, 2015 */
+
+/* Copyright (c) 1998-2014 Glenn Randers-Pehrson */
+
+/* This code is released under the libpng license. */
+/* For conditions of distribution and use, see the disclaimer */
+/* and license in png.h */
+
+/* pnglibconf.h */
+/* Machine generated file: DO NOT EDIT */
+/* Derived from: scripts/pnglibconf.dfa */
+#ifndef PNGLCONF_H
+#define PNGLCONF_H
+/* options */
+#define PNG_16BIT_SUPPORTED
+#define PNG_ALIGNED_MEMORY_SUPPORTED
+/*#undef PNG_ARM_NEON_API_SUPPORTED*/
+/*#undef PNG_ARM_NEON_CHECK_SUPPORTED*/
+#define PNG_BENIGN_ERRORS_SUPPORTED
+#define PNG_BENIGN_READ_ERRORS_SUPPORTED
+/*#undef PNG_BENIGN_WRITE_ERRORS_SUPPORTED*/
+#define PNG_BUILD_GRAYSCALE_PALETTE_SUPPORTED
+#define PNG_CHECK_FOR_INVALID_INDEX_SUPPORTED
+#define PNG_COLORSPACE_SUPPORTED
+#define PNG_CONSOLE_IO_SUPPORTED
+#ifndef _WIN32_WCE
+#define PNG_CONVERT_tIME_SUPPORTED
+#endif
+#define PNG_EASY_ACCESS_SUPPORTED
+/*#undef PNG_ERROR_NUMBERS_SUPPORTED*/
+#define PNG_ERROR_TEXT_SUPPORTED
+#define PNG_FIXED_POINT_SUPPORTED
+#define PNG_FLOATING_ARITHMETIC_SUPPORTED
+#define PNG_FLOATING_POINT_SUPPORTED
+#define PNG_FORMAT_AFIRST_SUPPORTED
+#define PNG_FORMAT_BGR_SUPPORTED
+#define PNG_GAMMA_SUPPORTED
+#define PNG_GET_PALETTE_MAX_SUPPORTED
+#define PNG_HANDLE_AS_UNKNOWN_SUPPORTED
+#define PNG_INCH_CONVERSIONS_SUPPORTED
+#define PNG_INFO_IMAGE_SUPPORTED
+#define PNG_IO_STATE_SUPPORTED
+#define PNG_MNG_FEATURES_SUPPORTED
+#define PNG_POINTER_INDEXING_SUPPORTED
+#define PNG_PROGRESSIVE_READ_SUPPORTED
+#define PNG_READ_16BIT_SUPPORTED
+#define PNG_READ_ALPHA_MODE_SUPPORTED
+#define PNG_READ_ANCILLARY_CHUNKS_SUPPORTED
+#define PNG_READ_BACKGROUND_SUPPORTED
+#define PNG_READ_BGR_SUPPORTED
+#define PNG_READ_CHECK_FOR_INVALID_INDEX_SUPPORTED
+#define PNG_READ_COMPOSITE_NODIV_SUPPORTED
+#define PNG_READ_COMPRESSED_TEXT_SUPPORTED
+#define PNG_READ_EXPAND_16_SUPPORTED
+#define PNG_READ_EXPAND_SUPPORTED
+#define PNG_READ_FILLER_SUPPORTED
+#define PNG_READ_GAMMA_SUPPORTED
+#define PNG_READ_GET_PALETTE_MAX_SUPPORTED
+#define PNG_READ_GRAY_TO_RGB_SUPPORTED
+#define PNG_READ_INTERLACING_SUPPORTED
+#define PNG_READ_INT_FUNCTIONS_SUPPORTED
+#define PNG_READ_INVERT_ALPHA_SUPPORTED
+#define PNG_READ_INVERT_SUPPORTED
+#define PNG_READ_OPT_PLTE_SUPPORTED
+#define PNG_READ_PACKSWAP_SUPPORTED
+#define PNG_READ_PACK_SUPPORTED
+#define PNG_READ_QUANTIZE_SUPPORTED
+#define PNG_READ_RGB_TO_GRAY_SUPPORTED
+#define PNG_READ_SCALE_16_TO_8_SUPPORTED
+#define PNG_READ_SHIFT_SUPPORTED
+#define PNG_READ_STRIP_16_TO_8_SUPPORTED
+#define PNG_READ_STRIP_ALPHA_SUPPORTED
+#define PNG_READ_SUPPORTED
+#define PNG_READ_SWAP_ALPHA_SUPPORTED
+#define PNG_READ_SWAP_SUPPORTED
+#define PNG_READ_TEXT_SUPPORTED
+#define PNG_READ_TRANSFORMS_SUPPORTED
+#define PNG_READ_UNKNOWN_CHUNKS_SUPPORTED
+#define PNG_READ_USER_CHUNKS_SUPPORTED
+#define PNG_READ_USER_TRANSFORM_SUPPORTED
+#define PNG_READ_bKGD_SUPPORTED
+#define PNG_READ_cHRM_SUPPORTED
+#define PNG_READ_gAMA_SUPPORTED
+#define PNG_READ_hIST_SUPPORTED
+#define PNG_READ_iCCP_SUPPORTED
+#define PNG_READ_iTXt_SUPPORTED
+#define PNG_READ_oFFs_SUPPORTED
+#define PNG_READ_pCAL_SUPPORTED
+#define PNG_READ_pHYs_SUPPORTED
+#define PNG_READ_sBIT_SUPPORTED
+#define PNG_READ_sCAL_SUPPORTED
+#define PNG_READ_sPLT_SUPPORTED
+#define PNG_READ_sRGB_SUPPORTED
+#define PNG_READ_tEXt_SUPPORTED
+#define PNG_READ_tIME_SUPPORTED
+#define PNG_READ_tRNS_SUPPORTED
+#define PNG_READ_zTXt_SUPPORTED
+#define PNG_SAVE_INT_32_SUPPORTED
+#define PNG_SAVE_UNKNOWN_CHUNKS_SUPPORTED
+#define PNG_SEQUENTIAL_READ_SUPPORTED
+#define PNG_SETJMP_SUPPORTED
+#define PNG_SET_CHUNK_CACHE_LIMIT_SUPPORTED
+#define PNG_SET_CHUNK_MALLOC_LIMIT_SUPPORTED
+#define PNG_SET_OPTION_SUPPORTED
+#define PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
+#define PNG_SET_USER_LIMITS_SUPPORTED
+#ifndef _WIN32_WCE
+#define PNG_SIMPLIFIED_READ_AFIRST_SUPPORTED
+#define PNG_SIMPLIFIED_READ_BGR_SUPPORTED
+#define PNG_SIMPLIFIED_READ_SUPPORTED
+#define PNG_SIMPLIFIED_WRITE_AFIRST_SUPPORTED
+#define PNG_SIMPLIFIED_WRITE_BGR_SUPPORTED
+#define PNG_SIMPLIFIED_WRITE_SUPPORTED
+#endif
+#define PNG_STDIO_SUPPORTED
+#define PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED
+#define PNG_TEXT_SUPPORTED
+#define PNG_TIME_RFC1123_SUPPORTED
+#define PNG_UNKNOWN_CHUNKS_SUPPORTED
+#define PNG_USER_CHUNKS_SUPPORTED
+#define PNG_USER_LIMITS_SUPPORTED
+#define PNG_USER_MEM_SUPPORTED
+#define PNG_USER_TRANSFORM_INFO_SUPPORTED
+#define PNG_USER_TRANSFORM_PTR_SUPPORTED
+#define PNG_WARNINGS_SUPPORTED
+#define PNG_WRITE_16BIT_SUPPORTED
+#define PNG_WRITE_ANCILLARY_CHUNKS_SUPPORTED
+#define PNG_WRITE_BGR_SUPPORTED
+#define PNG_WRITE_CHECK_FOR_INVALID_INDEX_SUPPORTED
+#define PNG_WRITE_COMPRESSED_TEXT_SUPPORTED
+#define PNG_WRITE_CUSTOMIZE_COMPRESSION_SUPPORTED
+#define PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED
+#define PNG_WRITE_FILLER_SUPPORTED
+#define PNG_WRITE_FILTER_SUPPORTED
+#define PNG_WRITE_FLUSH_SUPPORTED
+#define PNG_WRITE_GET_PALETTE_MAX_SUPPORTED
+#define PNG_WRITE_INTERLACING_SUPPORTED
+#define PNG_WRITE_INT_FUNCTIONS_SUPPORTED
+#define PNG_WRITE_INVERT_ALPHA_SUPPORTED
+#define PNG_WRITE_INVERT_SUPPORTED
+#define PNG_WRITE_OPTIMIZE_CMF_SUPPORTED
+#define PNG_WRITE_PACKSWAP_SUPPORTED
+#define PNG_WRITE_PACK_SUPPORTED
+#define PNG_WRITE_SHIFT_SUPPORTED
+#define PNG_WRITE_SUPPORTED
+#define PNG_WRITE_SWAP_ALPHA_SUPPORTED
+#define PNG_WRITE_SWAP_SUPPORTED
+#define PNG_WRITE_TEXT_SUPPORTED
+#define PNG_WRITE_TRANSFORMS_SUPPORTED
+#define PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED
+#define PNG_WRITE_USER_TRANSFORM_SUPPORTED
+#define PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
+#define PNG_WRITE_bKGD_SUPPORTED
+#define PNG_WRITE_cHRM_SUPPORTED
+#define PNG_WRITE_gAMA_SUPPORTED
+#define PNG_WRITE_hIST_SUPPORTED
+#define PNG_WRITE_iCCP_SUPPORTED
+#define PNG_WRITE_iTXt_SUPPORTED
+#define PNG_WRITE_oFFs_SUPPORTED
+#define PNG_WRITE_pCAL_SUPPORTED
+#define PNG_WRITE_pHYs_SUPPORTED
+#define PNG_WRITE_sBIT_SUPPORTED
+#define PNG_WRITE_sCAL_SUPPORTED
+#define PNG_WRITE_sPLT_SUPPORTED
+#define PNG_WRITE_sRGB_SUPPORTED
+#define PNG_WRITE_tEXt_SUPPORTED
+#define PNG_WRITE_tIME_SUPPORTED
+#define PNG_WRITE_tRNS_SUPPORTED
+#define PNG_WRITE_zTXt_SUPPORTED
+#define PNG_bKGD_SUPPORTED
+#define PNG_cHRM_SUPPORTED
+#define PNG_gAMA_SUPPORTED
+#define PNG_hIST_SUPPORTED
+#define PNG_iCCP_SUPPORTED
+#define PNG_iTXt_SUPPORTED
+#define PNG_oFFs_SUPPORTED
+#define PNG_pCAL_SUPPORTED
+#define PNG_pHYs_SUPPORTED
+#define PNG_sBIT_SUPPORTED
+#define PNG_sCAL_SUPPORTED
+#define PNG_sPLT_SUPPORTED
+#define PNG_sRGB_SUPPORTED
+#define PNG_tEXt_SUPPORTED
+#define PNG_tIME_SUPPORTED
+#define PNG_tRNS_SUPPORTED
+#define PNG_zTXt_SUPPORTED
+/* end of options */
+/* settings */
+#define PNG_API_RULE 0
+#define PNG_COST_SHIFT 3
+#define PNG_DEFAULT_READ_MACROS 1
+#define PNG_GAMMA_THRESHOLD_FIXED 5000
+#define PNG_IDAT_READ_SIZE PNG_ZBUF_SIZE
+#define PNG_INFLATE_BUF_SIZE 1024
+#define PNG_MAX_GAMMA_8 11
+#define PNG_QUANTIZE_BLUE_BITS 5
+#define PNG_QUANTIZE_GREEN_BITS 5
+#define PNG_QUANTIZE_RED_BITS 5
+#define PNG_TEXT_Z_DEFAULT_COMPRESSION (-1)
+#define PNG_TEXT_Z_DEFAULT_STRATEGY 0
+#define PNG_USER_CHUNK_CACHE_MAX 1000
+#define PNG_USER_CHUNK_MALLOC_MAX 8000000
+#define PNG_USER_HEIGHT_MAX 1000000
+#define PNG_USER_WIDTH_MAX 1000000
+#define PNG_WEIGHT_SHIFT 8
+#define PNG_ZBUF_SIZE 8192
+#define PNG_ZLIB_VERNUM 0 /* unknown */
+#define PNG_Z_DEFAULT_COMPRESSION (-1)
+#define PNG_Z_DEFAULT_NOFILTER_STRATEGY 0
+#define PNG_Z_DEFAULT_STRATEGY 1
+#define PNG_sCAL_PRECISION 5
+#define PNG_sRGB_PROFILE_CHECKS 2
+/* end of settings */
+#endif /* PNGLCONF_H */
--- /dev/null
+
+/* pngmem.c - stub functions for memory allocation
+ *
+ * Last changed in libpng 1.6.15 [November 20, 2014]
+ * Copyright (c) 1998-2014 Glenn Randers-Pehrson
+ * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
+ * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ *
+ * This file provides a location for all memory allocation. Users who
+ * need special memory handling are expected to supply replacement
+ * functions for png_malloc() and png_free(), and to use
+ * png_create_read_struct_2() and png_create_write_struct_2() to
+ * identify the replacement functions.
+ */
+
+#include "pngpriv.h"
+
+#if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
+/* Free a png_struct */
+void /* PRIVATE */
+png_destroy_png_struct(png_structrp png_ptr)
+{
+ if (png_ptr != NULL)
+ {
+ /* png_free might call png_error and may certainly call
+ * png_get_mem_ptr, so fake a temporary png_struct to support this.
+ */
+ png_struct dummy_struct = *png_ptr;
+ memset(png_ptr, 0, (sizeof *png_ptr));
+ png_free(&dummy_struct, png_ptr);
+
+# ifdef PNG_SETJMP_SUPPORTED
+ /* We may have a jmp_buf left to deallocate. */
+ png_free_jmpbuf(&dummy_struct);
+# endif
+ }
+}
+
+/* Allocate memory. For reasonable files, size should never exceed
+ * 64K. However, zlib may allocate more than 64K if you don't tell
+ * it not to. See zconf.h and png.h for more information. zlib does
+ * need to allocate exactly 64K, so whatever you call here must
+ * have the ability to do that.
+ */
+PNG_FUNCTION(png_voidp,PNGAPI
+png_calloc,(png_const_structrp png_ptr, png_alloc_size_t size),PNG_ALLOCATED)
+{
+ png_voidp ret;
+
+ ret = png_malloc(png_ptr, size);
+
+ if (ret != NULL)
+ memset(ret, 0, size);
+
+ return ret;
+}
+
+/* png_malloc_base, an internal function added at libpng 1.6.0, does the work of
+ * allocating memory, taking into account limits and PNG_USER_MEM_SUPPORTED.
+ * Checking and error handling must happen outside this routine; it returns NULL
+ * if the allocation cannot be done (for any reason.)
+ */
+PNG_FUNCTION(png_voidp /* PRIVATE */,
+png_malloc_base,(png_const_structrp png_ptr, png_alloc_size_t size),
+ PNG_ALLOCATED)
+{
+ /* Moved to png_malloc_base from png_malloc_default in 1.6.0; the DOS
+ * allocators have also been removed in 1.6.0, so any 16-bit system now has
+ * to implement a user memory handler. This checks to be sure it isn't
+ * called with big numbers.
+ */
+#ifndef PNG_USER_MEM_SUPPORTED
+ PNG_UNUSED(png_ptr)
+#endif
+
+ if (size > 0 && size <= PNG_SIZE_MAX
+# ifdef PNG_MAX_MALLOC_64K
+ && size <= 65536U
+# endif
+ )
+ {
+#ifdef PNG_USER_MEM_SUPPORTED
+ if (png_ptr != NULL && png_ptr->malloc_fn != NULL)
+ return png_ptr->malloc_fn(png_constcast(png_structrp,png_ptr), size);
+
+ else
+#endif
+ return malloc((size_t)size); /* checked for truncation above */
+ }
+
+ else
+ return NULL;
+}
+
+#if defined(PNG_TEXT_SUPPORTED) || defined(PNG_sPLT_SUPPORTED) ||\
+ defined(PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED)
+/* This is really here only to work round a spurious warning in GCC 4.6 and 4.7
+ * that arises because of the checks in png_realloc_array that are repeated in
+ * png_malloc_array.
+ */
+static png_voidp
+png_malloc_array_checked(png_const_structrp png_ptr, int nelements,
+ size_t element_size)
+{
+ png_alloc_size_t req = nelements; /* known to be > 0 */
+
+ if (req <= PNG_SIZE_MAX/element_size)
+ return png_malloc_base(png_ptr, req * element_size);
+
+ /* The failure case when the request is too large */
+ return NULL;
+}
+
+PNG_FUNCTION(png_voidp /* PRIVATE */,
+png_malloc_array,(png_const_structrp png_ptr, int nelements,
+ size_t element_size),PNG_ALLOCATED)
+{
+ if (nelements <= 0 || element_size == 0)
+ png_error(png_ptr, "internal error: array alloc");
+
+ return png_malloc_array_checked(png_ptr, nelements, element_size);
+}
+
+PNG_FUNCTION(png_voidp /* PRIVATE */,
+png_realloc_array,(png_const_structrp png_ptr, png_const_voidp old_array,
+ int old_elements, int add_elements, size_t element_size),PNG_ALLOCATED)
+{
+ /* These are internal errors: */
+ if (add_elements <= 0 || element_size == 0 || old_elements < 0 ||
+ (old_array == NULL && old_elements > 0))
+ png_error(png_ptr, "internal error: array realloc");
+
+ /* Check for overflow on the elements count (so the caller does not have to
+ * check.)
+ */
+ if (add_elements <= INT_MAX - old_elements)
+ {
+ png_voidp new_array = png_malloc_array_checked(png_ptr,
+ old_elements+add_elements, element_size);
+
+ if (new_array != NULL)
+ {
+ /* Because png_malloc_array worked the size calculations below cannot
+ * overflow.
+ */
+ if (old_elements > 0)
+ memcpy(new_array, old_array, element_size*(unsigned)old_elements);
+
+ memset((char*)new_array + element_size*(unsigned)old_elements, 0,
+ element_size*(unsigned)add_elements);
+
+ return new_array;
+ }
+ }
+
+ return NULL; /* error */
+}
+#endif /* TEXT || sPLT || STORE_UNKNOWN_CHUNKS */
+
+/* Various functions that have different error handling are derived from this.
+ * png_malloc always exists, but if PNG_USER_MEM_SUPPORTED is defined a separate
+ * function png_malloc_default is also provided.
+ */
+PNG_FUNCTION(png_voidp,PNGAPI
+png_malloc,(png_const_structrp png_ptr, png_alloc_size_t size),PNG_ALLOCATED)
+{
+ png_voidp ret;
+
+ if (png_ptr == NULL)
+ return NULL;
+
+ ret = png_malloc_base(png_ptr, size);
+
+ if (ret == NULL)
+ png_error(png_ptr, "Out of memory"); /* 'm' means png_malloc */
+
+ return ret;
+}
+
+#ifdef PNG_USER_MEM_SUPPORTED
+PNG_FUNCTION(png_voidp,PNGAPI
+png_malloc_default,(png_const_structrp png_ptr, png_alloc_size_t size),
+ PNG_ALLOCATED PNG_DEPRECATED)
+{
+ png_voidp ret;
+
+ if (png_ptr == NULL)
+ return NULL;
+
+ /* Passing 'NULL' here bypasses the application provided memory handler. */
+ ret = png_malloc_base(NULL/*use malloc*/, size);
+
+ if (ret == NULL)
+ png_error(png_ptr, "Out of Memory"); /* 'M' means png_malloc_default */
+
+ return ret;
+}
+#endif /* USER_MEM */
+
+/* This function was added at libpng version 1.2.3. The png_malloc_warn()
+ * function will issue a png_warning and return NULL instead of issuing a
+ * png_error, if it fails to allocate the requested memory.
+ */
+PNG_FUNCTION(png_voidp,PNGAPI
+png_malloc_warn,(png_const_structrp png_ptr, png_alloc_size_t size),
+ PNG_ALLOCATED)
+{
+ if (png_ptr != NULL)
+ {
+ png_voidp ret = png_malloc_base(png_ptr, size);
+
+ if (ret != NULL)
+ return ret;
+
+ png_warning(png_ptr, "Out of memory");
+ }
+
+ return NULL;
+}
+
+/* Free a pointer allocated by png_malloc(). If ptr is NULL, return
+ * without taking any action.
+ */
+void PNGAPI
+png_free(png_const_structrp png_ptr, png_voidp ptr)
+{
+ if (png_ptr == NULL || ptr == NULL)
+ return;
+
+#ifdef PNG_USER_MEM_SUPPORTED
+ if (png_ptr->free_fn != NULL)
+ png_ptr->free_fn(png_constcast(png_structrp,png_ptr), ptr);
+
+ else
+ png_free_default(png_ptr, ptr);
+}
+
+PNG_FUNCTION(void,PNGAPI
+png_free_default,(png_const_structrp png_ptr, png_voidp ptr),PNG_DEPRECATED)
+{
+ if (png_ptr == NULL || ptr == NULL)
+ return;
+#endif /* USER_MEM */
+
+ free(ptr);
+}
+
+#ifdef PNG_USER_MEM_SUPPORTED
+/* This function is called when the application wants to use another method
+ * of allocating and freeing memory.
+ */
+void PNGAPI
+png_set_mem_fn(png_structrp png_ptr, png_voidp mem_ptr, png_malloc_ptr
+ malloc_fn, png_free_ptr free_fn)
+{
+ if (png_ptr != NULL)
+ {
+ png_ptr->mem_ptr = mem_ptr;
+ png_ptr->malloc_fn = malloc_fn;
+ png_ptr->free_fn = free_fn;
+ }
+}
+
+/* This function returns a pointer to the mem_ptr associated with the user
+ * functions. The application should free any memory associated with this
+ * pointer before png_write_destroy and png_read_destroy are called.
+ */
+png_voidp PNGAPI
+png_get_mem_ptr(png_const_structrp png_ptr)
+{
+ if (png_ptr == NULL)
+ return NULL;
+
+ return png_ptr->mem_ptr;
+}
+#endif /* USER_MEM */
+#endif /* READ || WRITE */
--- /dev/null
+
+/* pngpread.c - read a png file in push mode
+ *
+ * Last changed in libpng 1.6.17 [March 26, 2015]
+ * Copyright (c) 1998-2015 Glenn Randers-Pehrson
+ * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
+ * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ */
+
+#include "pngpriv.h"
+
+#ifdef PNG_PROGRESSIVE_READ_SUPPORTED
+
+/* Push model modes */
+#define PNG_READ_SIG_MODE 0
+#define PNG_READ_CHUNK_MODE 1
+#define PNG_READ_IDAT_MODE 2
+#define PNG_SKIP_MODE 3
+#define PNG_READ_tEXt_MODE 4
+#define PNG_READ_zTXt_MODE 5
+#define PNG_READ_DONE_MODE 6
+#define PNG_READ_iTXt_MODE 7
+#define PNG_ERROR_MODE 8
+
+#define PNG_PUSH_SAVE_BUFFER_IF_FULL \
+if (png_ptr->push_length + 4 > png_ptr->buffer_size) \
+ { png_push_save_buffer(png_ptr); return; }
+#define PNG_PUSH_SAVE_BUFFER_IF_LT(N) \
+if (png_ptr->buffer_size < N) \
+ { png_push_save_buffer(png_ptr); return; }
+
+void PNGAPI
+png_process_data(png_structrp png_ptr, png_inforp info_ptr,
+ png_bytep buffer, png_size_t buffer_size)
+{
+ if (png_ptr == NULL || info_ptr == NULL)
+ return;
+
+ png_push_restore_buffer(png_ptr, buffer, buffer_size);
+
+ while (png_ptr->buffer_size)
+ {
+ png_process_some_data(png_ptr, info_ptr);
+ }
+}
+
+png_size_t PNGAPI
+png_process_data_pause(png_structrp png_ptr, int save)
+{
+ if (png_ptr != NULL)
+ {
+ /* It's easiest for the caller if we do the save; then the caller doesn't
+ * have to supply the same data again:
+ */
+ if (save != 0)
+ png_push_save_buffer(png_ptr);
+ else
+ {
+ /* This includes any pending saved bytes: */
+ png_size_t remaining = png_ptr->buffer_size;
+ png_ptr->buffer_size = 0;
+
+ /* So subtract the saved buffer size, unless all the data
+ * is actually 'saved', in which case we just return 0
+ */
+ if (png_ptr->save_buffer_size < remaining)
+ return remaining - png_ptr->save_buffer_size;
+ }
+ }
+
+ return 0;
+}
+
+png_uint_32 PNGAPI
+png_process_data_skip(png_structrp png_ptr)
+{
+ png_uint_32 remaining = 0;
+
+ if (png_ptr != NULL && png_ptr->process_mode == PNG_SKIP_MODE &&
+ png_ptr->skip_length > 0)
+ {
+ /* At the end of png_process_data the buffer size must be 0 (see the loop
+ * above) so we can detect a broken call here:
+ */
+ if (png_ptr->buffer_size != 0)
+ png_error(png_ptr,
+ "png_process_data_skip called inside png_process_data");
+
+ /* If is impossible for there to be a saved buffer at this point -
+ * otherwise we could not be in SKIP mode. This will also happen if
+ * png_process_skip is called inside png_process_data (but only very
+ * rarely.)
+ */
+ if (png_ptr->save_buffer_size != 0)
+ png_error(png_ptr, "png_process_data_skip called with saved data");
+
+ remaining = png_ptr->skip_length;
+ png_ptr->skip_length = 0;
+ png_ptr->process_mode = PNG_READ_CHUNK_MODE;
+ }
+
+ return remaining;
+}
+
+/* What we do with the incoming data depends on what we were previously
+ * doing before we ran out of data...
+ */
+void /* PRIVATE */
+png_process_some_data(png_structrp png_ptr, png_inforp info_ptr)
+{
+ if (png_ptr == NULL)
+ return;
+
+ switch (png_ptr->process_mode)
+ {
+ case PNG_READ_SIG_MODE:
+ {
+ png_push_read_sig(png_ptr, info_ptr);
+ break;
+ }
+
+ case PNG_READ_CHUNK_MODE:
+ {
+ png_push_read_chunk(png_ptr, info_ptr);
+ break;
+ }
+
+ case PNG_READ_IDAT_MODE:
+ {
+ png_push_read_IDAT(png_ptr);
+ break;
+ }
+
+ case PNG_SKIP_MODE:
+ {
+ png_push_crc_finish(png_ptr);
+ break;
+ }
+
+ default:
+ {
+ png_ptr->buffer_size = 0;
+ break;
+ }
+ }
+}
+
+/* Read any remaining signature bytes from the stream and compare them with
+ * the correct PNG signature. It is possible that this routine is called
+ * with bytes already read from the signature, either because they have been
+ * checked by the calling application, or because of multiple calls to this
+ * routine.
+ */
+void /* PRIVATE */
+png_push_read_sig(png_structrp png_ptr, png_inforp info_ptr)
+{
+ png_size_t num_checked = png_ptr->sig_bytes, /* SAFE, does not exceed 8 */
+ num_to_check = 8 - num_checked;
+
+ if (png_ptr->buffer_size < num_to_check)
+ {
+ num_to_check = png_ptr->buffer_size;
+ }
+
+ png_push_fill_buffer(png_ptr, &(info_ptr->signature[num_checked]),
+ num_to_check);
+ png_ptr->sig_bytes = (png_byte)(png_ptr->sig_bytes + num_to_check);
+
+ if (png_sig_cmp(info_ptr->signature, num_checked, num_to_check))
+ {
+ if (num_checked < 4 &&
+ png_sig_cmp(info_ptr->signature, num_checked, num_to_check - 4))
+ png_error(png_ptr, "Not a PNG file");
+
+ else
+ png_error(png_ptr, "PNG file corrupted by ASCII conversion");
+ }
+ else
+ {
+ if (png_ptr->sig_bytes >= 8)
+ {
+ png_ptr->process_mode = PNG_READ_CHUNK_MODE;
+ }
+ }
+}
+
+void /* PRIVATE */
+png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr)
+{
+ png_uint_32 chunk_name;
+#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
+ int keep; /* unknown handling method */
+#endif
+
+ /* First we make sure we have enough data for the 4-byte chunk name
+ * and the 4-byte chunk length before proceeding with decoding the
+ * chunk data. To fully decode each of these chunks, we also make
+ * sure we have enough data in the buffer for the 4-byte CRC at the
+ * end of every chunk (except IDAT, which is handled separately).
+ */
+ if ((png_ptr->mode & PNG_HAVE_CHUNK_HEADER) == 0)
+ {
+ png_byte chunk_length[4];
+ png_byte chunk_tag[4];
+
+ PNG_PUSH_SAVE_BUFFER_IF_LT(8)
+ png_push_fill_buffer(png_ptr, chunk_length, 4);
+ png_ptr->push_length = png_get_uint_31(png_ptr, chunk_length);
+ png_reset_crc(png_ptr);
+ png_crc_read(png_ptr, chunk_tag, 4);
+ png_ptr->chunk_name = PNG_CHUNK_FROM_STRING(chunk_tag);
+ png_check_chunk_name(png_ptr, png_ptr->chunk_name);
+ png_ptr->mode |= PNG_HAVE_CHUNK_HEADER;
+ }
+
+ chunk_name = png_ptr->chunk_name;
+
+ if (chunk_name == png_IDAT)
+ {
+ if ((png_ptr->mode & PNG_AFTER_IDAT) != 0)
+ png_ptr->mode |= PNG_HAVE_CHUNK_AFTER_IDAT;
+
+ /* If we reach an IDAT chunk, this means we have read all of the
+ * header chunks, and we can start reading the image (or if this
+ * is called after the image has been read - we have an error).
+ */
+ if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
+ png_error(png_ptr, "Missing IHDR before IDAT");
+
+ else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
+ (png_ptr->mode & PNG_HAVE_PLTE) == 0)
+ png_error(png_ptr, "Missing PLTE before IDAT");
+
+ png_ptr->mode |= PNG_HAVE_IDAT;
+ png_ptr->process_mode = PNG_READ_IDAT_MODE;
+
+ if ((png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT) == 0)
+ if (png_ptr->push_length == 0)
+ return;
+
+ if ((png_ptr->mode & PNG_AFTER_IDAT) != 0)
+ png_benign_error(png_ptr, "Too many IDATs found");
+ }
+
+ if (chunk_name == png_IHDR)
+ {
+ if (png_ptr->push_length != 13)
+ png_error(png_ptr, "Invalid IHDR length");
+
+ PNG_PUSH_SAVE_BUFFER_IF_FULL
+ png_handle_IHDR(png_ptr, info_ptr, png_ptr->push_length);
+ }
+
+ else if (chunk_name == png_IEND)
+ {
+ PNG_PUSH_SAVE_BUFFER_IF_FULL
+ png_handle_IEND(png_ptr, info_ptr, png_ptr->push_length);
+
+ png_ptr->process_mode = PNG_READ_DONE_MODE;
+ png_push_have_end(png_ptr, info_ptr);
+ }
+
+#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
+ else if ((keep = png_chunk_unknown_handling(png_ptr, chunk_name)) != 0)
+ {
+ PNG_PUSH_SAVE_BUFFER_IF_FULL
+ png_handle_unknown(png_ptr, info_ptr, png_ptr->push_length, keep);
+
+ if (chunk_name == png_PLTE)
+ png_ptr->mode |= PNG_HAVE_PLTE;
+ }
+#endif
+
+ else if (chunk_name == png_PLTE)
+ {
+ PNG_PUSH_SAVE_BUFFER_IF_FULL
+ png_handle_PLTE(png_ptr, info_ptr, png_ptr->push_length);
+ }
+
+ else if (chunk_name == png_IDAT)
+ {
+ png_ptr->idat_size = png_ptr->push_length;
+ png_ptr->process_mode = PNG_READ_IDAT_MODE;
+ png_push_have_info(png_ptr, info_ptr);
+ png_ptr->zstream.avail_out =
+ (uInt) PNG_ROWBYTES(png_ptr->pixel_depth,
+ png_ptr->iwidth) + 1;
+ png_ptr->zstream.next_out = png_ptr->row_buf;
+ return;
+ }
+
+#ifdef PNG_READ_gAMA_SUPPORTED
+ else if (png_ptr->chunk_name == png_gAMA)
+ {
+ PNG_PUSH_SAVE_BUFFER_IF_FULL
+ png_handle_gAMA(png_ptr, info_ptr, png_ptr->push_length);
+ }
+
+#endif
+#ifdef PNG_READ_sBIT_SUPPORTED
+ else if (png_ptr->chunk_name == png_sBIT)
+ {
+ PNG_PUSH_SAVE_BUFFER_IF_FULL
+ png_handle_sBIT(png_ptr, info_ptr, png_ptr->push_length);
+ }
+
+#endif
+#ifdef PNG_READ_cHRM_SUPPORTED
+ else if (png_ptr->chunk_name == png_cHRM)
+ {
+ PNG_PUSH_SAVE_BUFFER_IF_FULL
+ png_handle_cHRM(png_ptr, info_ptr, png_ptr->push_length);
+ }
+
+#endif
+#ifdef PNG_READ_sRGB_SUPPORTED
+ else if (chunk_name == png_sRGB)
+ {
+ PNG_PUSH_SAVE_BUFFER_IF_FULL
+ png_handle_sRGB(png_ptr, info_ptr, png_ptr->push_length);
+ }
+
+#endif
+#ifdef PNG_READ_iCCP_SUPPORTED
+ else if (png_ptr->chunk_name == png_iCCP)
+ {
+ PNG_PUSH_SAVE_BUFFER_IF_FULL
+ png_handle_iCCP(png_ptr, info_ptr, png_ptr->push_length);
+ }
+
+#endif
+#ifdef PNG_READ_sPLT_SUPPORTED
+ else if (chunk_name == png_sPLT)
+ {
+ PNG_PUSH_SAVE_BUFFER_IF_FULL
+ png_handle_sPLT(png_ptr, info_ptr, png_ptr->push_length);
+ }
+
+#endif
+#ifdef PNG_READ_tRNS_SUPPORTED
+ else if (chunk_name == png_tRNS)
+ {
+ PNG_PUSH_SAVE_BUFFER_IF_FULL
+ png_handle_tRNS(png_ptr, info_ptr, png_ptr->push_length);
+ }
+
+#endif
+#ifdef PNG_READ_bKGD_SUPPORTED
+ else if (chunk_name == png_bKGD)
+ {
+ PNG_PUSH_SAVE_BUFFER_IF_FULL
+ png_handle_bKGD(png_ptr, info_ptr, png_ptr->push_length);
+ }
+
+#endif
+#ifdef PNG_READ_hIST_SUPPORTED
+ else if (chunk_name == png_hIST)
+ {
+ PNG_PUSH_SAVE_BUFFER_IF_FULL
+ png_handle_hIST(png_ptr, info_ptr, png_ptr->push_length);
+ }
+
+#endif
+#ifdef PNG_READ_pHYs_SUPPORTED
+ else if (chunk_name == png_pHYs)
+ {
+ PNG_PUSH_SAVE_BUFFER_IF_FULL
+ png_handle_pHYs(png_ptr, info_ptr, png_ptr->push_length);
+ }
+
+#endif
+#ifdef PNG_READ_oFFs_SUPPORTED
+ else if (chunk_name == png_oFFs)
+ {
+ PNG_PUSH_SAVE_BUFFER_IF_FULL
+ png_handle_oFFs(png_ptr, info_ptr, png_ptr->push_length);
+ }
+#endif
+
+#ifdef PNG_READ_pCAL_SUPPORTED
+ else if (chunk_name == png_pCAL)
+ {
+ PNG_PUSH_SAVE_BUFFER_IF_FULL
+ png_handle_pCAL(png_ptr, info_ptr, png_ptr->push_length);
+ }
+
+#endif
+#ifdef PNG_READ_sCAL_SUPPORTED
+ else if (chunk_name == png_sCAL)
+ {
+ PNG_PUSH_SAVE_BUFFER_IF_FULL
+ png_handle_sCAL(png_ptr, info_ptr, png_ptr->push_length);
+ }
+
+#endif
+#ifdef PNG_READ_tIME_SUPPORTED
+ else if (chunk_name == png_tIME)
+ {
+ PNG_PUSH_SAVE_BUFFER_IF_FULL
+ png_handle_tIME(png_ptr, info_ptr, png_ptr->push_length);
+ }
+
+#endif
+#ifdef PNG_READ_tEXt_SUPPORTED
+ else if (chunk_name == png_tEXt)
+ {
+ PNG_PUSH_SAVE_BUFFER_IF_FULL
+ png_handle_tEXt(png_ptr, info_ptr, png_ptr->push_length);
+ }
+
+#endif
+#ifdef PNG_READ_zTXt_SUPPORTED
+ else if (chunk_name == png_zTXt)
+ {
+ PNG_PUSH_SAVE_BUFFER_IF_FULL
+ png_handle_zTXt(png_ptr, info_ptr, png_ptr->push_length);
+ }
+
+#endif
+#ifdef PNG_READ_iTXt_SUPPORTED
+ else if (chunk_name == png_iTXt)
+ {
+ PNG_PUSH_SAVE_BUFFER_IF_FULL
+ png_handle_iTXt(png_ptr, info_ptr, png_ptr->push_length);
+ }
+#endif
+
+ else
+ {
+ PNG_PUSH_SAVE_BUFFER_IF_FULL
+ png_handle_unknown(png_ptr, info_ptr, png_ptr->push_length,
+ PNG_HANDLE_CHUNK_AS_DEFAULT);
+ }
+
+ png_ptr->mode &= ~PNG_HAVE_CHUNK_HEADER;
+}
+
+void /* PRIVATE */
+png_push_crc_skip(png_structrp png_ptr, png_uint_32 skip)
+{
+ png_ptr->process_mode = PNG_SKIP_MODE;
+ png_ptr->skip_length = skip;
+}
+
+void /* PRIVATE */
+png_push_crc_finish(png_structrp png_ptr)
+{
+ if (png_ptr->skip_length != 0 && png_ptr->save_buffer_size != 0)
+ {
+ png_size_t save_size = png_ptr->save_buffer_size;
+ png_uint_32 skip_length = png_ptr->skip_length;
+
+ /* We want the smaller of 'skip_length' and 'save_buffer_size', but
+ * they are of different types and we don't know which variable has the
+ * fewest bits. Carefully select the smaller and cast it to the type of
+ * the larger - this cannot overflow. Do not cast in the following test
+ * - it will break on either 16 or 64 bit platforms.
+ */
+ if (skip_length < save_size)
+ save_size = (png_size_t)skip_length;
+
+ else
+ skip_length = (png_uint_32)save_size;
+
+ png_calculate_crc(png_ptr, png_ptr->save_buffer_ptr, save_size);
+
+ png_ptr->skip_length -= skip_length;
+ png_ptr->buffer_size -= save_size;
+ png_ptr->save_buffer_size -= save_size;
+ png_ptr->save_buffer_ptr += save_size;
+ }
+ if (png_ptr->skip_length != 0 && png_ptr->current_buffer_size != 0)
+ {
+ png_size_t save_size = png_ptr->current_buffer_size;
+ png_uint_32 skip_length = png_ptr->skip_length;
+
+ /* We want the smaller of 'skip_length' and 'current_buffer_size', here,
+ * the same problem exists as above and the same solution.
+ */
+ if (skip_length < save_size)
+ save_size = (png_size_t)skip_length;
+
+ else
+ skip_length = (png_uint_32)save_size;
+
+ png_calculate_crc(png_ptr, png_ptr->current_buffer_ptr, save_size);
+
+ png_ptr->skip_length -= skip_length;
+ png_ptr->buffer_size -= save_size;
+ png_ptr->current_buffer_size -= save_size;
+ png_ptr->current_buffer_ptr += save_size;
+ }
+ if (png_ptr->skip_length == 0)
+ {
+ PNG_PUSH_SAVE_BUFFER_IF_LT(4)
+ png_crc_finish(png_ptr, 0);
+ png_ptr->process_mode = PNG_READ_CHUNK_MODE;
+ }
+}
+
+void PNGCBAPI
+png_push_fill_buffer(png_structp png_ptr, png_bytep buffer, png_size_t length)
+{
+ png_bytep ptr;
+
+ if (png_ptr == NULL)
+ return;
+
+ ptr = buffer;
+ if (png_ptr->save_buffer_size != 0)
+ {
+ png_size_t save_size;
+
+ if (length < png_ptr->save_buffer_size)
+ save_size = length;
+
+ else
+ save_size = png_ptr->save_buffer_size;
+
+ memcpy(ptr, png_ptr->save_buffer_ptr, save_size);
+ length -= save_size;
+ ptr += save_size;
+ png_ptr->buffer_size -= save_size;
+ png_ptr->save_buffer_size -= save_size;
+ png_ptr->save_buffer_ptr += save_size;
+ }
+ if (length != 0 && png_ptr->current_buffer_size != 0)
+ {
+ png_size_t save_size;
+
+ if (length < png_ptr->current_buffer_size)
+ save_size = length;
+
+ else
+ save_size = png_ptr->current_buffer_size;
+
+ memcpy(ptr, png_ptr->current_buffer_ptr, save_size);
+ png_ptr->buffer_size -= save_size;
+ png_ptr->current_buffer_size -= save_size;
+ png_ptr->current_buffer_ptr += save_size;
+ }
+}
+
+void /* PRIVATE */
+png_push_save_buffer(png_structrp png_ptr)
+{
+ if (png_ptr->save_buffer_size != 0)
+ {
+ if (png_ptr->save_buffer_ptr != png_ptr->save_buffer)
+ {
+ png_size_t i, istop;
+ png_bytep sp;
+ png_bytep dp;
+
+ istop = png_ptr->save_buffer_size;
+ for (i = 0, sp = png_ptr->save_buffer_ptr, dp = png_ptr->save_buffer;
+ i < istop; i++, sp++, dp++)
+ {
+ *dp = *sp;
+ }
+ }
+ }
+ if (png_ptr->save_buffer_size + png_ptr->current_buffer_size >
+ png_ptr->save_buffer_max)
+ {
+ png_size_t new_max;
+ png_bytep old_buffer;
+
+ if (png_ptr->save_buffer_size > PNG_SIZE_MAX -
+ (png_ptr->current_buffer_size + 256))
+ {
+ png_error(png_ptr, "Potential overflow of save_buffer");
+ }
+
+ new_max = png_ptr->save_buffer_size + png_ptr->current_buffer_size + 256;
+ old_buffer = png_ptr->save_buffer;
+ png_ptr->save_buffer = (png_bytep)png_malloc_warn(png_ptr,
+ (png_size_t)new_max);
+
+ if (png_ptr->save_buffer == NULL)
+ {
+ png_free(png_ptr, old_buffer);
+ old_buffer = NULL;
+ png_error(png_ptr, "Insufficient memory for save_buffer");
+ }
+
+ memcpy(png_ptr->save_buffer, old_buffer, png_ptr->save_buffer_size);
+ png_free(png_ptr, old_buffer);
+ old_buffer = NULL;
+ png_ptr->save_buffer_max = new_max;
+ }
+ if (png_ptr->current_buffer_size)
+ {
+ memcpy(png_ptr->save_buffer + png_ptr->save_buffer_size,
+ png_ptr->current_buffer_ptr, png_ptr->current_buffer_size);
+ png_ptr->save_buffer_size += png_ptr->current_buffer_size;
+ png_ptr->current_buffer_size = 0;
+ }
+ png_ptr->save_buffer_ptr = png_ptr->save_buffer;
+ png_ptr->buffer_size = 0;
+}
+
+void /* PRIVATE */
+png_push_restore_buffer(png_structrp png_ptr, png_bytep buffer,
+ png_size_t buffer_length)
+{
+ png_ptr->current_buffer = buffer;
+ png_ptr->current_buffer_size = buffer_length;
+ png_ptr->buffer_size = buffer_length + png_ptr->save_buffer_size;
+ png_ptr->current_buffer_ptr = png_ptr->current_buffer;
+}
+
+void /* PRIVATE */
+png_push_read_IDAT(png_structrp png_ptr)
+{
+ if ((png_ptr->mode & PNG_HAVE_CHUNK_HEADER) == 0)
+ {
+ png_byte chunk_length[4];
+ png_byte chunk_tag[4];
+
+ /* TODO: this code can be commoned up with the same code in push_read */
+ PNG_PUSH_SAVE_BUFFER_IF_LT(8)
+ png_push_fill_buffer(png_ptr, chunk_length, 4);
+ png_ptr->push_length = png_get_uint_31(png_ptr, chunk_length);
+ png_reset_crc(png_ptr);
+ png_crc_read(png_ptr, chunk_tag, 4);
+ png_ptr->chunk_name = PNG_CHUNK_FROM_STRING(chunk_tag);
+ png_ptr->mode |= PNG_HAVE_CHUNK_HEADER;
+
+ if (png_ptr->chunk_name != png_IDAT)
+ {
+ png_ptr->process_mode = PNG_READ_CHUNK_MODE;
+
+ if ((png_ptr->flags & PNG_FLAG_ZSTREAM_ENDED) == 0)
+ png_error(png_ptr, "Not enough compressed data");
+
+ return;
+ }
+
+ png_ptr->idat_size = png_ptr->push_length;
+ }
+
+ if (png_ptr->idat_size != 0 && png_ptr->save_buffer_size != 0)
+ {
+ png_size_t save_size = png_ptr->save_buffer_size;
+ png_uint_32 idat_size = png_ptr->idat_size;
+
+ /* We want the smaller of 'idat_size' and 'current_buffer_size', but they
+ * are of different types and we don't know which variable has the fewest
+ * bits. Carefully select the smaller and cast it to the type of the
+ * larger - this cannot overflow. Do not cast in the following test - it
+ * will break on either 16 or 64 bit platforms.
+ */
+ if (idat_size < save_size)
+ save_size = (png_size_t)idat_size;
+
+ else
+ idat_size = (png_uint_32)save_size;
+
+ png_calculate_crc(png_ptr, png_ptr->save_buffer_ptr, save_size);
+
+ png_process_IDAT_data(png_ptr, png_ptr->save_buffer_ptr, save_size);
+
+ png_ptr->idat_size -= idat_size;
+ png_ptr->buffer_size -= save_size;
+ png_ptr->save_buffer_size -= save_size;
+ png_ptr->save_buffer_ptr += save_size;
+ }
+
+ if (png_ptr->idat_size != 0 && png_ptr->current_buffer_size != 0)
+ {
+ png_size_t save_size = png_ptr->current_buffer_size;
+ png_uint_32 idat_size = png_ptr->idat_size;
+
+ /* We want the smaller of 'idat_size' and 'current_buffer_size', but they
+ * are of different types and we don't know which variable has the fewest
+ * bits. Carefully select the smaller and cast it to the type of the
+ * larger - this cannot overflow.
+ */
+ if (idat_size < save_size)
+ save_size = (png_size_t)idat_size;
+
+ else
+ idat_size = (png_uint_32)save_size;
+
+ png_calculate_crc(png_ptr, png_ptr->current_buffer_ptr, save_size);
+
+ png_process_IDAT_data(png_ptr, png_ptr->current_buffer_ptr, save_size);
+
+ png_ptr->idat_size -= idat_size;
+ png_ptr->buffer_size -= save_size;
+ png_ptr->current_buffer_size -= save_size;
+ png_ptr->current_buffer_ptr += save_size;
+ }
+ if (png_ptr->idat_size == 0)
+ {
+ PNG_PUSH_SAVE_BUFFER_IF_LT(4)
+ png_crc_finish(png_ptr, 0);
+ png_ptr->mode &= ~PNG_HAVE_CHUNK_HEADER;
+ png_ptr->mode |= PNG_AFTER_IDAT;
+ png_ptr->zowner = 0;
+ }
+}
+
+void /* PRIVATE */
+png_process_IDAT_data(png_structrp png_ptr, png_bytep buffer,
+ png_size_t buffer_length)
+{
+ /* The caller checks for a non-zero buffer length. */
+ if (!(buffer_length > 0) || buffer == NULL)
+ png_error(png_ptr, "No IDAT data (internal error)");
+
+ /* This routine must process all the data it has been given
+ * before returning, calling the row callback as required to
+ * handle the uncompressed results.
+ */
+ png_ptr->zstream.next_in = buffer;
+ /* TODO: WARNING: TRUNCATION ERROR: DANGER WILL ROBINSON: */
+ png_ptr->zstream.avail_in = (uInt)buffer_length;
+
+ /* Keep going until the decompressed data is all processed
+ * or the stream marked as finished.
+ */
+ while (png_ptr->zstream.avail_in > 0 &&
+ (png_ptr->flags & PNG_FLAG_ZSTREAM_ENDED) == 0)
+ {
+ int ret;
+
+ /* We have data for zlib, but we must check that zlib
+ * has someplace to put the results. It doesn't matter
+ * if we don't expect any results -- it may be the input
+ * data is just the LZ end code.
+ */
+ if (!(png_ptr->zstream.avail_out > 0))
+ {
+ /* TODO: WARNING: TRUNCATION ERROR: DANGER WILL ROBINSON: */
+ png_ptr->zstream.avail_out = (uInt)(PNG_ROWBYTES(png_ptr->pixel_depth,
+ png_ptr->iwidth) + 1);
+
+ png_ptr->zstream.next_out = png_ptr->row_buf;
+ }
+
+ /* Using Z_SYNC_FLUSH here means that an unterminated
+ * LZ stream (a stream with a missing end code) can still
+ * be handled, otherwise (Z_NO_FLUSH) a future zlib
+ * implementation might defer output and therefore
+ * change the current behavior (see comments in inflate.c
+ * for why this doesn't happen at present with zlib 1.2.5).
+ */
+ ret = inflate(&png_ptr->zstream, Z_SYNC_FLUSH);
+
+ /* Check for any failure before proceeding. */
+ if (ret != Z_OK && ret != Z_STREAM_END)
+ {
+ /* Terminate the decompression. */
+ png_ptr->flags |= PNG_FLAG_ZSTREAM_ENDED;
+ png_ptr->zowner = 0;
+
+ /* This may be a truncated stream (missing or
+ * damaged end code). Treat that as a warning.
+ */
+ if (png_ptr->row_number >= png_ptr->num_rows ||
+ png_ptr->pass > 6)
+ png_warning(png_ptr, "Truncated compressed data in IDAT");
+
+ else
+ png_error(png_ptr, "Decompression error in IDAT");
+
+ /* Skip the check on unprocessed input */
+ return;
+ }
+
+ /* Did inflate output any data? */
+ if (png_ptr->zstream.next_out != png_ptr->row_buf)
+ {
+ /* Is this unexpected data after the last row?
+ * If it is, artificially terminate the LZ output
+ * here.
+ */
+ if (png_ptr->row_number >= png_ptr->num_rows ||
+ png_ptr->pass > 6)
+ {
+ /* Extra data. */
+ png_warning(png_ptr, "Extra compressed data in IDAT");
+ png_ptr->flags |= PNG_FLAG_ZSTREAM_ENDED;
+ png_ptr->zowner = 0;
+
+ /* Do no more processing; skip the unprocessed
+ * input check below.
+ */
+ return;
+ }
+
+ /* Do we have a complete row? */
+ if (png_ptr->zstream.avail_out == 0)
+ png_push_process_row(png_ptr);
+ }
+
+ /* And check for the end of the stream. */
+ if (ret == Z_STREAM_END)
+ png_ptr->flags |= PNG_FLAG_ZSTREAM_ENDED;
+ }
+
+ /* All the data should have been processed, if anything
+ * is left at this point we have bytes of IDAT data
+ * after the zlib end code.
+ */
+ if (png_ptr->zstream.avail_in > 0)
+ png_warning(png_ptr, "Extra compression data in IDAT");
+}
+
+void /* PRIVATE */
+png_push_process_row(png_structrp png_ptr)
+{
+ /* 1.5.6: row_info moved out of png_struct to a local here. */
+ png_row_info row_info;
+
+ row_info.width = png_ptr->iwidth; /* NOTE: width of current interlaced row */
+ row_info.color_type = png_ptr->color_type;
+ row_info.bit_depth = png_ptr->bit_depth;
+ row_info.channels = png_ptr->channels;
+ row_info.pixel_depth = png_ptr->pixel_depth;
+ row_info.rowbytes = PNG_ROWBYTES(row_info.pixel_depth, row_info.width);
+
+ if (png_ptr->row_buf[0] > PNG_FILTER_VALUE_NONE)
+ {
+ if (png_ptr->row_buf[0] < PNG_FILTER_VALUE_LAST)
+ png_read_filter_row(png_ptr, &row_info, png_ptr->row_buf + 1,
+ png_ptr->prev_row + 1, png_ptr->row_buf[0]);
+ else
+ png_error(png_ptr, "bad adaptive filter value");
+ }
+
+ /* libpng 1.5.6: the following line was copying png_ptr->rowbytes before
+ * 1.5.6, while the buffer really is this big in current versions of libpng
+ * it may not be in the future, so this was changed just to copy the
+ * interlaced row count:
+ */
+ memcpy(png_ptr->prev_row, png_ptr->row_buf, row_info.rowbytes + 1);
+
+#ifdef PNG_READ_TRANSFORMS_SUPPORTED
+ if (png_ptr->transformations != 0)
+ png_do_read_transformations(png_ptr, &row_info);
+#endif
+
+ /* The transformed pixel depth should match the depth now in row_info. */
+ if (png_ptr->transformed_pixel_depth == 0)
+ {
+ png_ptr->transformed_pixel_depth = row_info.pixel_depth;
+ if (row_info.pixel_depth > png_ptr->maximum_pixel_depth)
+ png_error(png_ptr, "progressive row overflow");
+ }
+
+ else if (png_ptr->transformed_pixel_depth != row_info.pixel_depth)
+ png_error(png_ptr, "internal progressive row size calculation error");
+
+
+#ifdef PNG_READ_INTERLACING_SUPPORTED
+ /* Expand interlaced rows to full size */
+ if (png_ptr->interlaced != 0 &&
+ (png_ptr->transformations & PNG_INTERLACE) != 0)
+ {
+ if (png_ptr->pass < 6)
+ png_do_read_interlace(&row_info, png_ptr->row_buf + 1, png_ptr->pass,
+ png_ptr->transformations);
+
+ switch (png_ptr->pass)
+ {
+ case 0:
+ {
+ int i;
+ for (i = 0; i < 8 && png_ptr->pass == 0; i++)
+ {
+ png_push_have_row(png_ptr, png_ptr->row_buf + 1);
+ png_read_push_finish_row(png_ptr); /* Updates png_ptr->pass */
+ }
+
+ if (png_ptr->pass == 2) /* Pass 1 might be empty */
+ {
+ for (i = 0; i < 4 && png_ptr->pass == 2; i++)
+ {
+ png_push_have_row(png_ptr, NULL);
+ png_read_push_finish_row(png_ptr);
+ }
+ }
+
+ if (png_ptr->pass == 4 && png_ptr->height <= 4)
+ {
+ for (i = 0; i < 2 && png_ptr->pass == 4; i++)
+ {
+ png_push_have_row(png_ptr, NULL);
+ png_read_push_finish_row(png_ptr);
+ }
+ }
+
+ if (png_ptr->pass == 6 && png_ptr->height <= 4)
+ {
+ png_push_have_row(png_ptr, NULL);
+ png_read_push_finish_row(png_ptr);
+ }
+
+ break;
+ }
+
+ case 1:
+ {
+ int i;
+ for (i = 0; i < 8 && png_ptr->pass == 1; i++)
+ {
+ png_push_have_row(png_ptr, png_ptr->row_buf + 1);
+ png_read_push_finish_row(png_ptr);
+ }
+
+ if (png_ptr->pass == 2) /* Skip top 4 generated rows */
+ {
+ for (i = 0; i < 4 && png_ptr->pass == 2; i++)
+ {
+ png_push_have_row(png_ptr, NULL);
+ png_read_push_finish_row(png_ptr);
+ }
+ }
+
+ break;
+ }
+
+ case 2:
+ {
+ int i;
+
+ for (i = 0; i < 4 && png_ptr->pass == 2; i++)
+ {
+ png_push_have_row(png_ptr, png_ptr->row_buf + 1);
+ png_read_push_finish_row(png_ptr);
+ }
+
+ for (i = 0; i < 4 && png_ptr->pass == 2; i++)
+ {
+ png_push_have_row(png_ptr, NULL);
+ png_read_push_finish_row(png_ptr);
+ }
+
+ if (png_ptr->pass == 4) /* Pass 3 might be empty */
+ {
+ for (i = 0; i < 2 && png_ptr->pass == 4; i++)
+ {
+ png_push_have_row(png_ptr, NULL);
+ png_read_push_finish_row(png_ptr);
+ }
+ }
+
+ break;
+ }
+
+ case 3:
+ {
+ int i;
+
+ for (i = 0; i < 4 && png_ptr->pass == 3; i++)
+ {
+ png_push_have_row(png_ptr, png_ptr->row_buf + 1);
+ png_read_push_finish_row(png_ptr);
+ }
+
+ if (png_ptr->pass == 4) /* Skip top two generated rows */
+ {
+ for (i = 0; i < 2 && png_ptr->pass == 4; i++)
+ {
+ png_push_have_row(png_ptr, NULL);
+ png_read_push_finish_row(png_ptr);
+ }
+ }
+
+ break;
+ }
+
+ case 4:
+ {
+ int i;
+
+ for (i = 0; i < 2 && png_ptr->pass == 4; i++)
+ {
+ png_push_have_row(png_ptr, png_ptr->row_buf + 1);
+ png_read_push_finish_row(png_ptr);
+ }
+
+ for (i = 0; i < 2 && png_ptr->pass == 4; i++)
+ {
+ png_push_have_row(png_ptr, NULL);
+ png_read_push_finish_row(png_ptr);
+ }
+
+ if (png_ptr->pass == 6) /* Pass 5 might be empty */
+ {
+ png_push_have_row(png_ptr, NULL);
+ png_read_push_finish_row(png_ptr);
+ }
+
+ break;
+ }
+
+ case 5:
+ {
+ int i;
+
+ for (i = 0; i < 2 && png_ptr->pass == 5; i++)
+ {
+ png_push_have_row(png_ptr, png_ptr->row_buf + 1);
+ png_read_push_finish_row(png_ptr);
+ }
+
+ if (png_ptr->pass == 6) /* Skip top generated row */
+ {
+ png_push_have_row(png_ptr, NULL);
+ png_read_push_finish_row(png_ptr);
+ }
+
+ break;
+ }
+
+ default:
+ case 6:
+ {
+ png_push_have_row(png_ptr, png_ptr->row_buf + 1);
+ png_read_push_finish_row(png_ptr);
+
+ if (png_ptr->pass != 6)
+ break;
+
+ png_push_have_row(png_ptr, NULL);
+ png_read_push_finish_row(png_ptr);
+ }
+ }
+ }
+ else
+#endif
+ {
+ png_push_have_row(png_ptr, png_ptr->row_buf + 1);
+ png_read_push_finish_row(png_ptr);
+ }
+}
+
+void /* PRIVATE */
+png_read_push_finish_row(png_structrp png_ptr)
+{
+#ifdef PNG_READ_INTERLACING_SUPPORTED
+ /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
+
+ /* Start of interlace block */
+ static PNG_CONST png_byte png_pass_start[] = {0, 4, 0, 2, 0, 1, 0};
+
+ /* Offset to next interlace block */
+ static PNG_CONST png_byte png_pass_inc[] = {8, 8, 4, 4, 2, 2, 1};
+
+ /* Start of interlace block in the y direction */
+ static PNG_CONST png_byte png_pass_ystart[] = {0, 0, 4, 0, 2, 0, 1};
+
+ /* Offset to next interlace block in the y direction */
+ static PNG_CONST png_byte png_pass_yinc[] = {8, 8, 8, 4, 4, 2, 2};
+
+ /* Height of interlace block. This is not currently used - if you need
+ * it, uncomment it here and in png.h
+ static PNG_CONST png_byte png_pass_height[] = {8, 8, 4, 4, 2, 2, 1};
+ */
+#endif
+
+ png_ptr->row_number++;
+ if (png_ptr->row_number < png_ptr->num_rows)
+ return;
+
+#ifdef PNG_READ_INTERLACING_SUPPORTED
+ if (png_ptr->interlaced != 0)
+ {
+ png_ptr->row_number = 0;
+ memset(png_ptr->prev_row, 0, png_ptr->rowbytes + 1);
+
+ do
+ {
+ png_ptr->pass++;
+ if ((png_ptr->pass == 1 && png_ptr->width < 5) ||
+ (png_ptr->pass == 3 && png_ptr->width < 3) ||
+ (png_ptr->pass == 5 && png_ptr->width < 2))
+ png_ptr->pass++;
+
+ if (png_ptr->pass > 7)
+ png_ptr->pass--;
+
+ if (png_ptr->pass >= 7)
+ break;
+
+ png_ptr->iwidth = (png_ptr->width +
+ png_pass_inc[png_ptr->pass] - 1 -
+ png_pass_start[png_ptr->pass]) /
+ png_pass_inc[png_ptr->pass];
+
+ if ((png_ptr->transformations & PNG_INTERLACE) != 0)
+ break;
+
+ png_ptr->num_rows = (png_ptr->height +
+ png_pass_yinc[png_ptr->pass] - 1 -
+ png_pass_ystart[png_ptr->pass]) /
+ png_pass_yinc[png_ptr->pass];
+
+ } while (png_ptr->iwidth == 0 || png_ptr->num_rows == 0);
+ }
+#endif /* READ_INTERLACING */
+}
+
+void /* PRIVATE */
+png_push_have_info(png_structrp png_ptr, png_inforp info_ptr)
+{
+ if (png_ptr->info_fn != NULL)
+ (*(png_ptr->info_fn))(png_ptr, info_ptr);
+}
+
+void /* PRIVATE */
+png_push_have_end(png_structrp png_ptr, png_inforp info_ptr)
+{
+ if (png_ptr->end_fn != NULL)
+ (*(png_ptr->end_fn))(png_ptr, info_ptr);
+}
+
+void /* PRIVATE */
+png_push_have_row(png_structrp png_ptr, png_bytep row)
+{
+ if (png_ptr->row_fn != NULL)
+ (*(png_ptr->row_fn))(png_ptr, row, png_ptr->row_number,
+ (int)png_ptr->pass);
+}
+
+#ifdef PNG_READ_INTERLACING_SUPPORTED
+void PNGAPI
+png_progressive_combine_row(png_const_structrp png_ptr, png_bytep old_row,
+ png_const_bytep new_row)
+{
+ if (png_ptr == NULL)
+ return;
+
+ /* new_row is a flag here - if it is NULL then the app callback was called
+ * from an empty row (see the calls to png_struct::row_fn below), otherwise
+ * it must be png_ptr->row_buf+1
+ */
+ if (new_row != NULL)
+ png_combine_row(png_ptr, old_row, 1/*blocky display*/);
+}
+#endif /* READ_INTERLACING */
+
+void PNGAPI
+png_set_progressive_read_fn(png_structrp png_ptr, png_voidp progressive_ptr,
+ png_progressive_info_ptr info_fn, png_progressive_row_ptr row_fn,
+ png_progressive_end_ptr end_fn)
+{
+ if (png_ptr == NULL)
+ return;
+
+ png_ptr->info_fn = info_fn;
+ png_ptr->row_fn = row_fn;
+ png_ptr->end_fn = end_fn;
+
+ png_set_read_fn(png_ptr, progressive_ptr, png_push_fill_buffer);
+}
+
+png_voidp PNGAPI
+png_get_progressive_ptr(png_const_structrp png_ptr)
+{
+ if (png_ptr == NULL)
+ return (NULL);
+
+ return png_ptr->io_ptr;
+}
+#endif /* PROGRESSIVE_READ */
--- /dev/null
+
+/* pngpriv.h - private declarations for use inside libpng
+ *
+ * Last changed in libpng 1.6.17 [March 26, 2015]
+ * Copyright (c) 1998-2015 Glenn Randers-Pehrson
+ * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
+ * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ */
+
+/* The symbols declared in this file (including the functions declared
+ * as extern) are PRIVATE. They are not part of the libpng public
+ * interface, and are not recommended for use by regular applications.
+ * Some of them may become public in the future; others may stay private,
+ * change in an incompatible way, or even disappear.
+ * Although the libpng users are not forbidden to include this header,
+ * they should be well aware of the issues that may arise from doing so.
+ */
+
+#ifndef PNGPRIV_H
+#define PNGPRIV_H
+
+#ifdef _MSC_VER
+# ifndef _CRT_SECURE_NO_DEPRECATE
+# define _CRT_SECURE_NO_DEPRECATE
+# endif
+#endif
+
+/* Feature Test Macros. The following are defined here to ensure that correctly
+ * implemented libraries reveal the APIs libpng needs to build and hide those
+ * that are not needed and potentially damaging to the compilation.
+ *
+ * Feature Test Macros must be defined before any system header is included (see
+ * POSIX 1003.1 2.8.2 "POSIX Symbols."
+ *
+ * These macros only have an effect if the operating system supports either
+ * POSIX 1003.1 or C99, or both. On other operating systems (particularly
+ * Windows/Visual Studio) there is no effect; the OS specific tests below are
+ * still required (as of 2011-05-02.)
+ */
+#define _POSIX_SOURCE 1 /* Just the POSIX 1003.1 and C89 APIs */
+
+#ifndef PNG_VERSION_INFO_ONLY
+/* Standard library headers not required by png.h: */
+# include <stdlib.h>
+# include <string.h>
+#endif
+
+#define PNGLIB_BUILD /*libpng is being built, not used*/
+
+/* If HAVE_CONFIG_H is defined during the build then the build system must
+ * provide an appropriate "config.h" file on the include path. The header file
+ * must provide definitions as required below (search for "HAVE_CONFIG_H");
+ * see configure.ac for more details of the requirements. The macro
+ * "PNG_NO_CONFIG_H" is provided for maintainers to test for dependencies on
+ * 'configure'; define this macro to prevent the configure build including the
+ * configure generated config.h. Libpng is expected to compile without *any*
+ * special build system support on a reasonably ANSI-C compliant system.
+ */
+#if defined(HAVE_CONFIG_H) && !defined(PNG_NO_CONFIG_H)
+# include <config.h>
+
+ /* Pick up the definition of 'restrict' from config.h if it was read: */
+# define PNG_RESTRICT restrict
+#endif
+
+/* To support symbol prefixing it is necessary to know *before* including png.h
+ * whether the fixed point (and maybe other) APIs are exported, because if they
+ * are not internal definitions may be required. This is handled below just
+ * before png.h is included, but load the configuration now if it is available.
+ */
+#ifndef PNGLCONF_H
+# include "pnglibconf.h"
+#endif
+
+/* Local renames may change non-exported API functions from png.h */
+#if defined(PNG_PREFIX) && !defined(PNGPREFIX_H)
+# include "pngprefix.h"
+#endif
+
+#ifdef PNG_USER_CONFIG
+# include "pngusr.h"
+ /* These should have been defined in pngusr.h */
+# ifndef PNG_USER_PRIVATEBUILD
+# define PNG_USER_PRIVATEBUILD "Custom libpng build"
+# endif
+# ifndef PNG_USER_DLLFNAME_POSTFIX
+# define PNG_USER_DLLFNAME_POSTFIX "Cb"
+# endif
+#endif
+
+/* Compile time options.
+ * =====================
+ * In a multi-arch build the compiler may compile the code several times for the
+ * same object module, producing different binaries for different architectures.
+ * When this happens configure-time setting of the target host options cannot be
+ * done and this interferes with the handling of the ARM NEON optimizations, and
+ * possibly other similar optimizations. Put additional tests here; in general
+ * this is needed when the same option can be changed at both compile time and
+ * run time depending on the target OS (i.e. iOS vs Android.)
+ *
+ * NOTE: symbol prefixing does not pass $(CFLAGS) to the preprocessor, because
+ * this is not possible with certain compilers (Oracle SUN OS CC), as a result
+ * it is necessary to ensure that all extern functions that *might* be used
+ * regardless of $(CFLAGS) get declared in this file. The test on __ARM_NEON__
+ * below is one example of this behavior because it is controlled by the
+ * presence or not of -mfpu=neon on the GCC command line, it is possible to do
+ * this in $(CC), e.g. "CC=gcc -mfpu=neon", but people who build libpng rarely
+ * do this.
+ */
+#ifndef PNG_ARM_NEON_OPT
+ /* ARM NEON optimizations are being controlled by the compiler settings,
+ * typically the target FPU. If the FPU has been set to NEON (-mfpu=neon
+ * with GCC) then the compiler will define __ARM_NEON__ and we can rely
+ * unconditionally on NEON instructions not crashing, otherwise we must
+ * disable use of NEON instructions.
+ *
+ * NOTE: at present these optimizations depend on 'ALIGNED_MEMORY', so they
+ * can only be turned on automatically if that is supported too. If
+ * PNG_ARM_NEON_OPT is set in CPPFLAGS (to >0) then arm/arm_init.c will fail
+ * to compile with an appropriate #error if ALIGNED_MEMORY has been turned
+ * off.
+ *
+ * Note that gcc-4.9 defines __ARM_NEON instead of __ARM_NEON__, so we
+ * check both variants.
+ */
+# if (defined(__ARM_NEON__) || defined(__ARM_NEON)) && \
+ defined(PNG_ALIGNED_MEMORY_SUPPORTED)
+# define PNG_ARM_NEON_OPT 2
+# else
+# define PNG_ARM_NEON_OPT 0
+# endif
+#endif
+
+#if PNG_ARM_NEON_OPT > 0
+ /* NEON optimizations are to be at least considered by libpng, so enable the
+ * callbacks to do this.
+ */
+# define PNG_FILTER_OPTIMIZATIONS png_init_filter_functions_neon
+
+ /* By default the 'intrinsics' code in arm/filter_neon_intrinsics.c is used
+ * if possible - if __ARM_NEON__ is set and the compiler version is not known
+ * to be broken. This is controlled by PNG_ARM_NEON_IMPLEMENTATION which can
+ * be:
+ *
+ * 1 The intrinsics code (the default with __ARM_NEON__)
+ * 2 The hand coded assembler (the default without __ARM_NEON__)
+ *
+ * It is possible to set PNG_ARM_NEON_IMPLEMENTATION in CPPFLAGS, however
+ * this is *NOT* supported and may cease to work even after a minor revision
+ * to libpng. It *is* valid to do this for testing purposes, e.g. speed
+ * testing or a new compiler, but the results should be communicated to the
+ * libpng implementation list for incorporation in the next minor release.
+ */
+# ifndef PNG_ARM_NEON_IMPLEMENTATION
+# if defined(__ARM_NEON__) || defined(__ARM_NEON)
+# if defined(__clang__)
+ /* At present it is unknown by the libpng developers which versions
+ * of clang support the intrinsics, however some or perhaps all
+ * versions do not work with the assembler so this may be
+ * irrelevant, so just use the default (do nothing here.)
+ */
+# elif defined(__GNUC__)
+ /* GCC 4.5.4 NEON support is known to be broken. 4.6.3 is known to
+ * work, so if this *is* GCC, or G++, look for a version >4.5
+ */
+# if __GNUC__ < 4 || (__GNUC__ == 4 && __GNUC_MINOR__ < 6)
+# define PNG_ARM_NEON_IMPLEMENTATION 2
+# endif /* no GNUC support */
+# endif /* __GNUC__ */
+# else /* !defined __ARM_NEON__ */
+ /* The 'intrinsics' code simply won't compile without this -mfpu=neon:
+ */
+# define PNG_ARM_NEON_IMPLEMENTATION 2
+# endif /* __ARM_NEON__ */
+# endif /* !PNG_ARM_NEON_IMPLEMENTATION */
+
+# ifndef PNG_ARM_NEON_IMPLEMENTATION
+ /* Use the intrinsics code by default. */
+# define PNG_ARM_NEON_IMPLEMENTATION 1
+# endif
+#endif /* PNG_ARM_NEON_OPT > 0 */
+
+/* Is this a build of a DLL where compilation of the object modules requires
+ * different preprocessor settings to those required for a simple library? If
+ * so PNG_BUILD_DLL must be set.
+ *
+ * If libpng is used inside a DLL but that DLL does not export the libpng APIs
+ * PNG_BUILD_DLL must not be set. To avoid the code below kicking in build a
+ * static library of libpng then link the DLL against that.
+ */
+#ifndef PNG_BUILD_DLL
+# ifdef DLL_EXPORT
+ /* This is set by libtool when files are compiled for a DLL; libtool
+ * always compiles twice, even on systems where it isn't necessary. Set
+ * PNG_BUILD_DLL in case it is necessary:
+ */
+# define PNG_BUILD_DLL
+# else
+# ifdef _WINDLL
+ /* This is set by the Microsoft Visual Studio IDE in projects that
+ * build a DLL. It can't easily be removed from those projects (it
+ * isn't visible in the Visual Studio UI) so it is a fairly reliable
+ * indication that PNG_IMPEXP needs to be set to the DLL export
+ * attributes.
+ */
+# define PNG_BUILD_DLL
+# else
+# ifdef __DLL__
+ /* This is set by the Borland C system when compiling for a DLL
+ * (as above.)
+ */
+# define PNG_BUILD_DLL
+# else
+ /* Add additional compiler cases here. */
+# endif
+# endif
+# endif
+#endif /* Setting PNG_BUILD_DLL if required */
+
+/* Modfied for usage in Qt: Do not export the libpng APIs */
+#ifdef PNG_BUILD_DLL
+#undef PNG_BUILD_DLL
+#endif
+
+/* See pngconf.h for more details: the builder of the library may set this on
+ * the command line to the right thing for the specific compilation system or it
+ * may be automagically set above (at present we know of no system where it does
+ * need to be set on the command line.)
+ *
+ * PNG_IMPEXP must be set here when building the library to prevent pngconf.h
+ * setting it to the "import" setting for a DLL build.
+ */
+#ifndef PNG_IMPEXP
+# ifdef PNG_BUILD_DLL
+# define PNG_IMPEXP PNG_DLL_EXPORT
+# else
+ /* Not building a DLL, or the DLL doesn't require specific export
+ * definitions.
+ */
+# define PNG_IMPEXP
+# endif
+#endif
+
+/* No warnings for private or deprecated functions in the build: */
+#ifndef PNG_DEPRECATED
+# define PNG_DEPRECATED
+#endif
+#ifndef PNG_PRIVATE
+# define PNG_PRIVATE
+#endif
+
+/* Symbol preprocessing support.
+ *
+ * To enable listing global, but internal, symbols the following macros should
+ * always be used to declare an extern data or function object in this file.
+ */
+#ifndef PNG_INTERNAL_DATA
+# define PNG_INTERNAL_DATA(type, name, array) extern type name array
+#endif
+
+#ifndef PNG_INTERNAL_FUNCTION
+# define PNG_INTERNAL_FUNCTION(type, name, args, attributes)\
+ extern PNG_FUNCTION(type, name, args, PNG_EMPTY attributes)
+#endif
+
+#ifndef PNG_INTERNAL_CALLBACK
+# define PNG_INTERNAL_CALLBACK(type, name, args, attributes)\
+ extern PNG_FUNCTION(type, (PNGCBAPI name), args, PNG_EMPTY attributes)
+#endif
+
+/* If floating or fixed point APIs are disabled they may still be compiled
+ * internally. To handle this make sure they are declared as the appropriate
+ * internal extern function (otherwise the symbol prefixing stuff won't work and
+ * the functions will be used without definitions.)
+ *
+ * NOTE: although all the API functions are declared here they are not all
+ * actually built! Because the declarations are still made it is necessary to
+ * fake out types that they depend on.
+ */
+#ifndef PNG_FP_EXPORT
+# ifndef PNG_FLOATING_POINT_SUPPORTED
+# define PNG_FP_EXPORT(ordinal, type, name, args)\
+ PNG_INTERNAL_FUNCTION(type, name, args, PNG_EMPTY);
+# ifndef PNG_VERSION_INFO_ONLY
+ typedef struct png_incomplete png_double;
+ typedef png_double* png_doublep;
+ typedef const png_double* png_const_doublep;
+ typedef png_double** png_doublepp;
+# endif
+# endif
+#endif
+#ifndef PNG_FIXED_EXPORT
+# ifndef PNG_FIXED_POINT_SUPPORTED
+# define PNG_FIXED_EXPORT(ordinal, type, name, args)\
+ PNG_INTERNAL_FUNCTION(type, name, args, PNG_EMPTY);
+# endif
+#endif
+
+#include "png.h"
+
+/* pngconf.h does not set PNG_DLL_EXPORT unless it is required, so: */
+#ifndef PNG_DLL_EXPORT
+# define PNG_DLL_EXPORT
+#endif
+
+/* SECURITY and SAFETY:
+ *
+ * libpng is built with support for internal limits on image dimensions and
+ * memory usage. These are documented in scripts/pnglibconf.dfa of the
+ * source and recorded in the machine generated header file pnglibconf.h.
+ */
+
+/* If you are running on a machine where you cannot allocate more
+ * than 64K of memory at once, uncomment this. While libpng will not
+ * normally need that much memory in a chunk (unless you load up a very
+ * large file), zlib needs to know how big of a chunk it can use, and
+ * libpng thus makes sure to check any memory allocation to verify it
+ * will fit into memory.
+ *
+ * zlib provides 'MAXSEG_64K' which, if defined, indicates the
+ * same limit and pngconf.h (already included) sets the limit
+ * if certain operating systems are detected.
+ */
+#if defined(MAXSEG_64K) && !defined(PNG_MAX_MALLOC_64K)
+# define PNG_MAX_MALLOC_64K
+#endif
+
+#ifndef PNG_UNUSED
+/* Unused formal parameter warnings are silenced using the following macro
+ * which is expected to have no bad effects on performance (optimizing
+ * compilers will probably remove it entirely). Note that if you replace
+ * it with something other than whitespace, you must include the terminating
+ * semicolon.
+ */
+# define PNG_UNUSED(param) (void)param;
+#endif
+
+/* Just a little check that someone hasn't tried to define something
+ * contradictory.
+ */
+#if (PNG_ZBUF_SIZE > 65536L) && defined(PNG_MAX_MALLOC_64K)
+# undef PNG_ZBUF_SIZE
+# define PNG_ZBUF_SIZE 65536L
+#endif
+
+/* If warnings or errors are turned off the code is disabled or redirected here.
+ * From 1.5.4 functions have been added to allow very limited formatting of
+ * error and warning messages - this code will also be disabled here.
+ */
+#ifdef PNG_WARNINGS_SUPPORTED
+# define PNG_WARNING_PARAMETERS(p) png_warning_parameters p;
+#else
+# define png_warning_parameter(p,number,string) ((void)0)
+# define png_warning_parameter_unsigned(p,number,format,value) ((void)0)
+# define png_warning_parameter_signed(p,number,format,value) ((void)0)
+# define png_formatted_warning(pp,p,message) ((void)(pp))
+# define PNG_WARNING_PARAMETERS(p)
+#endif
+#ifndef PNG_ERROR_TEXT_SUPPORTED
+# define png_fixed_error(s1,s2) png_err(s1)
+#endif
+
+/* C allows up-casts from (void*) to any pointer and (const void*) to any
+ * pointer to a const object. C++ regards this as a type error and requires an
+ * explicit, static, cast and provides the static_cast<> rune to ensure that
+ * const is not cast away.
+ */
+#ifdef __cplusplus
+# define png_voidcast(type, value) static_cast<type>(value)
+# define png_constcast(type, value) const_cast<type>(value)
+# define png_aligncast(type, value) \
+ static_cast<type>(static_cast<void*>(value))
+# define png_aligncastconst(type, value) \
+ static_cast<type>(static_cast<const void*>(value))
+#else
+# define png_voidcast(type, value) (value)
+# define png_constcast(type, value) ((type)(value))
+# define png_aligncast(type, value) ((void*)(value))
+# define png_aligncastconst(type, value) ((const void*)(value))
+#endif /* __cplusplus */
+
+/* Some fixed point APIs are still required even if not exported because
+ * they get used by the corresponding floating point APIs. This magic
+ * deals with this:
+ */
+#ifdef PNG_FIXED_POINT_SUPPORTED
+# define PNGFAPI PNGAPI
+#else
+# define PNGFAPI /* PRIVATE */
+#endif
+
+#ifndef PNG_VERSION_INFO_ONLY
+/* Other defines specific to compilers can go here. Try to keep
+ * them inside an appropriate ifdef/endif pair for portability.
+ */
+#if defined(PNG_FLOATING_POINT_SUPPORTED) ||\
+ defined(PNG_FLOATING_ARITHMETIC_SUPPORTED)
+ /* png.c requires the following ANSI-C constants if the conversion of
+ * floating point to ASCII is implemented therein:
+ *
+ * DBL_DIG Maximum number of decimal digits (can be set to any constant)
+ * DBL_MIN Smallest normalized fp number (can be set to an arbitrary value)
+ * DBL_MAX Maximum floating point number (can be set to an arbitrary value)
+ */
+# include <float.h>
+
+# if (defined(__MWERKS__) && defined(macintosh)) || defined(applec) || \
+ defined(THINK_C) || defined(__SC__) || defined(TARGET_OS_MAC)
+ /* We need to check that <math.h> hasn't already been included earlier
+ * as it seems it doesn't agree with <fp.h>, yet we should really use
+ * <fp.h> if possible.
+ */
+# if !defined(__MATH_H__) && !defined(__MATH_H) && !defined(__cmath__)
+# include <fp.h>
+# endif
+# else
+# include <math.h>
+# endif
+# if defined(_AMIGA) && defined(__SASC) && defined(_M68881)
+ /* Amiga SAS/C: We must include builtin FPU functions when compiling using
+ * MATH=68881
+ */
+# include <m68881.h>
+# endif
+#endif
+
+/* This provides the non-ANSI (far) memory allocation routines. */
+#if defined(__TURBOC__) && defined(__MSDOS__)
+# include <mem.h>
+# include <alloc.h>
+#endif
+
+#if defined(WIN32) || defined(_Windows) || defined(_WINDOWS) || \
+ defined(_WIN32) || defined(__WIN32__)
+# if !defined(__SYMBIAN32__)
+# include <windows.h> /* defines _WINDOWS_ macro */
+# endif
+#endif
+#endif /* PNG_VERSION_INFO_ONLY */
+
+/* Moved here around 1.5.0beta36 from pngconf.h */
+/* Users may want to use these so they are not private. Any library
+ * functions that are passed far data must be model-independent.
+ */
+
+/* Memory model/platform independent fns */
+#ifndef PNG_ABORT
+# if defined(_WINDOWS_) || defined(_WIN32_WCE)
+# define PNG_ABORT() ExitProcess(0)
+# else
+# define PNG_ABORT() abort()
+# endif
+#endif
+
+/* These macros may need to be architecture dependent. */
+#define PNG_ALIGN_NONE 0 /* do not use data alignment */
+#define PNG_ALIGN_ALWAYS 1 /* assume unaligned accesses are OK */
+#ifdef offsetof
+# define PNG_ALIGN_OFFSET 2 /* use offsetof to determine alignment */
+#else
+# define PNG_ALIGN_OFFSET -1 /* prevent the use of this */
+#endif
+#define PNG_ALIGN_SIZE 3 /* use sizeof to determine alignment */
+
+#ifndef PNG_ALIGN_TYPE
+ /* Default to using aligned access optimizations and requiring alignment to a
+ * multiple of the data type size. Override in a compiler specific fashion
+ * if necessary by inserting tests here:
+ */
+# define PNG_ALIGN_TYPE PNG_ALIGN_SIZE
+#endif
+
+#if PNG_ALIGN_TYPE == PNG_ALIGN_SIZE
+ /* This is used because in some compiler implementations non-aligned
+ * structure members are supported, so the offsetof approach below fails.
+ * Set PNG_ALIGN_SIZE=0 for compiler combinations where unaligned access
+ * is good for performance. Do not do this unless you have tested the result
+ * and understand it.
+ */
+# define png_alignof(type) (sizeof (type))
+#else
+# if PNG_ALIGN_TYPE == PNG_ALIGN_OFFSET
+# define png_alignof(type) offsetof(struct{char c; type t;}, t)
+# else
+# if PNG_ALIGN_TYPE == PNG_ALIGN_ALWAYS
+# define png_alignof(type) (1)
+# endif
+ /* Else leave png_alignof undefined to prevent use thereof */
+# endif
+#endif
+
+/* This implicitly assumes alignment is always to a power of 2. */
+#ifdef png_alignof
+# define png_isaligned(ptr, type)\
+ ((((const char*)ptr-(const char*)0) & (png_alignof(type)-1)) == 0)
+#else
+# define png_isaligned(ptr, type) 0
+#endif
+
+/* End of memory model/platform independent support */
+/* End of 1.5.0beta36 move from pngconf.h */
+
+/* CONSTANTS and UTILITY MACROS
+ * These are used internally by libpng and not exposed in the API
+ */
+
+/* Various modes of operation. Note that after an init, mode is set to
+ * zero automatically when the structure is created. Three of these
+ * are defined in png.h because they need to be visible to applications
+ * that call png_set_unknown_chunk().
+ */
+/* #define PNG_HAVE_IHDR 0x01 (defined in png.h) */
+/* #define PNG_HAVE_PLTE 0x02 (defined in png.h) */
+#define PNG_HAVE_IDAT 0x04
+/* #define PNG_AFTER_IDAT 0x08 (defined in png.h) */
+#define PNG_HAVE_IEND 0x10
+ /* 0x20 (unused) */
+ /* 0x40 (unused) */
+ /* 0x80 (unused) */
+#define PNG_HAVE_CHUNK_HEADER 0x100
+#define PNG_WROTE_tIME 0x200
+#define PNG_WROTE_INFO_BEFORE_PLTE 0x400
+#define PNG_BACKGROUND_IS_GRAY 0x800
+#define PNG_HAVE_PNG_SIGNATURE 0x1000
+#define PNG_HAVE_CHUNK_AFTER_IDAT 0x2000 /* Have another chunk after IDAT */
+ /* 0x4000 (unused) */
+#define PNG_IS_READ_STRUCT 0x8000 /* Else is a write struct */
+
+/* Flags for the transformations the PNG library does on the image data */
+#define PNG_BGR 0x0001
+#define PNG_INTERLACE 0x0002
+#define PNG_PACK 0x0004
+#define PNG_SHIFT 0x0008
+#define PNG_SWAP_BYTES 0x0010
+#define PNG_INVERT_MONO 0x0020
+#define PNG_QUANTIZE 0x0040
+#define PNG_COMPOSE 0x0080 /* Was PNG_BACKGROUND */
+#define PNG_BACKGROUND_EXPAND 0x0100
+#define PNG_EXPAND_16 0x0200 /* Added to libpng 1.5.2 */
+#define PNG_16_TO_8 0x0400 /* Becomes 'chop' in 1.5.4 */
+#define PNG_RGBA 0x0800
+#define PNG_EXPAND 0x1000
+#define PNG_GAMMA 0x2000
+#define PNG_GRAY_TO_RGB 0x4000
+#define PNG_FILLER 0x8000
+#define PNG_PACKSWAP 0x10000
+#define PNG_SWAP_ALPHA 0x20000
+#define PNG_STRIP_ALPHA 0x40000
+#define PNG_INVERT_ALPHA 0x80000
+#define PNG_USER_TRANSFORM 0x100000
+#define PNG_RGB_TO_GRAY_ERR 0x200000
+#define PNG_RGB_TO_GRAY_WARN 0x400000
+#define PNG_RGB_TO_GRAY 0x600000 /* two bits, RGB_TO_GRAY_ERR|WARN */
+#define PNG_ENCODE_ALPHA 0x800000 /* Added to libpng-1.5.4 */
+#define PNG_ADD_ALPHA 0x1000000 /* Added to libpng-1.2.7 */
+#define PNG_EXPAND_tRNS 0x2000000 /* Added to libpng-1.2.9 */
+#define PNG_SCALE_16_TO_8 0x4000000 /* Added to libpng-1.5.4 */
+ /* 0x8000000 unused */
+ /* 0x10000000 unused */
+ /* 0x20000000 unused */
+ /* 0x40000000 unused */
+/* Flags for png_create_struct */
+#define PNG_STRUCT_PNG 0x0001
+#define PNG_STRUCT_INFO 0x0002
+
+/* Scaling factor for filter heuristic weighting calculations */
+#define PNG_WEIGHT_FACTOR (1<<(PNG_WEIGHT_SHIFT))
+#define PNG_COST_FACTOR (1<<(PNG_COST_SHIFT))
+
+/* Flags for the png_ptr->flags rather than declaring a byte for each one */
+#define PNG_FLAG_ZLIB_CUSTOM_STRATEGY 0x0001
+#define PNG_FLAG_ZSTREAM_INITIALIZED 0x0002 /* Added to libpng-1.6.0 */
+ /* 0x0004 unused */
+#define PNG_FLAG_ZSTREAM_ENDED 0x0008 /* Added to libpng-1.6.0 */
+ /* 0x0010 unused */
+ /* 0x0020 unused */
+#define PNG_FLAG_ROW_INIT 0x0040
+#define PNG_FLAG_FILLER_AFTER 0x0080
+#define PNG_FLAG_CRC_ANCILLARY_USE 0x0100
+#define PNG_FLAG_CRC_ANCILLARY_NOWARN 0x0200
+#define PNG_FLAG_CRC_CRITICAL_USE 0x0400
+#define PNG_FLAG_CRC_CRITICAL_IGNORE 0x0800
+#define PNG_FLAG_ASSUME_sRGB 0x1000 /* Added to libpng-1.5.4 */
+#define PNG_FLAG_OPTIMIZE_ALPHA 0x2000 /* Added to libpng-1.5.4 */
+#define PNG_FLAG_DETECT_UNINITIALIZED 0x4000 /* Added to libpng-1.5.4 */
+/* #define PNG_FLAG_KEEP_UNKNOWN_CHUNKS 0x8000 */
+/* #define PNG_FLAG_KEEP_UNSAFE_CHUNKS 0x10000 */
+#define PNG_FLAG_LIBRARY_MISMATCH 0x20000
+#define PNG_FLAG_STRIP_ERROR_NUMBERS 0x40000
+#define PNG_FLAG_STRIP_ERROR_TEXT 0x80000
+#define PNG_FLAG_BENIGN_ERRORS_WARN 0x100000 /* Added to libpng-1.4.0 */
+#define PNG_FLAG_APP_WARNINGS_WARN 0x200000 /* Added to libpng-1.6.0 */
+#define PNG_FLAG_APP_ERRORS_WARN 0x400000 /* Added to libpng-1.6.0 */
+ /* 0x800000 unused */
+ /* 0x1000000 unused */
+ /* 0x2000000 unused */
+ /* 0x4000000 unused */
+ /* 0x8000000 unused */
+ /* 0x10000000 unused */
+ /* 0x20000000 unused */
+ /* 0x40000000 unused */
+
+#define PNG_FLAG_CRC_ANCILLARY_MASK (PNG_FLAG_CRC_ANCILLARY_USE | \
+ PNG_FLAG_CRC_ANCILLARY_NOWARN)
+
+#define PNG_FLAG_CRC_CRITICAL_MASK (PNG_FLAG_CRC_CRITICAL_USE | \
+ PNG_FLAG_CRC_CRITICAL_IGNORE)
+
+#define PNG_FLAG_CRC_MASK (PNG_FLAG_CRC_ANCILLARY_MASK | \
+ PNG_FLAG_CRC_CRITICAL_MASK)
+
+/* Save typing and make code easier to understand */
+
+#define PNG_COLOR_DIST(c1, c2) (abs((int)((c1).red) - (int)((c2).red)) + \
+ abs((int)((c1).green) - (int)((c2).green)) + \
+ abs((int)((c1).blue) - (int)((c2).blue)))
+
+/* Added to libpng-1.6.0: scale a 16-bit value in the range 0..65535 to 0..255
+ * by dividing by 257 *with rounding*. This macro is exact for the given range.
+ * See the discourse in pngrtran.c png_do_scale_16_to_8. The values in the
+ * macro were established by experiment (modifying the added value). The macro
+ * has a second variant that takes a value already scaled by 255 and divides by
+ * 65535 - this has a maximum error of .502. Over the range 0..65535*65535 it
+ * only gives off-by-one errors and only for 0.5% (1 in 200) of the values.
+ */
+#define PNG_DIV65535(v24) (((v24) + 32895) >> 16)
+#define PNG_DIV257(v16) PNG_DIV65535((png_uint_32)(v16) * 255)
+
+/* Added to libpng-1.2.6 JB */
+#define PNG_ROWBYTES(pixel_bits, width) \
+ ((pixel_bits) >= 8 ? \
+ ((png_size_t)(width) * (((png_size_t)(pixel_bits)) >> 3)) : \
+ (( ((png_size_t)(width) * ((png_size_t)(pixel_bits))) + 7) >> 3) )
+
+/* PNG_OUT_OF_RANGE returns true if value is outside the range
+ * ideal-delta..ideal+delta. Each argument is evaluated twice.
+ * "ideal" and "delta" should be constants, normally simple
+ * integers, "value" a variable. Added to libpng-1.2.6 JB
+ */
+#define PNG_OUT_OF_RANGE(value, ideal, delta) \
+ ( (value) < (ideal)-(delta) || (value) > (ideal)+(delta) )
+
+/* Conversions between fixed and floating point, only defined if
+ * required (to make sure the code doesn't accidentally use float
+ * when it is supposedly disabled.)
+ */
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+/* The floating point conversion can't overflow, though it can and
+ * does lose accuracy relative to the original fixed point value.
+ * In practice this doesn't matter because png_fixed_point only
+ * stores numbers with very low precision. The png_ptr and s
+ * arguments are unused by default but are there in case error
+ * checking becomes a requirement.
+ */
+#define png_float(png_ptr, fixed, s) (.00001 * (fixed))
+
+/* The fixed point conversion performs range checking and evaluates
+ * its argument multiple times, so must be used with care. The
+ * range checking uses the PNG specification values for a signed
+ * 32 bit fixed point value except that the values are deliberately
+ * rounded-to-zero to an integral value - 21474 (21474.83 is roughly
+ * (2^31-1) * 100000). 's' is a string that describes the value being
+ * converted.
+ *
+ * NOTE: this macro will raise a png_error if the range check fails,
+ * therefore it is normally only appropriate to use this on values
+ * that come from API calls or other sources where an out of range
+ * error indicates a programming error, not a data error!
+ *
+ * NOTE: by default this is off - the macro is not used - because the
+ * function call saves a lot of code.
+ */
+#ifdef PNG_FIXED_POINT_MACRO_SUPPORTED
+#define png_fixed(png_ptr, fp, s) ((fp) <= 21474 && (fp) >= -21474 ?\
+ ((png_fixed_point)(100000 * (fp))) : (png_fixed_error(png_ptr, s),0))
+#endif
+/* else the corresponding function is defined below, inside the scope of the
+ * cplusplus test.
+ */
+#endif
+
+/* Constants for known chunk types. If you need to add a chunk, define the name
+ * here. For historical reasons these constants have the form png_<name>; i.e.
+ * the prefix is lower case. Please use decimal values as the parameters to
+ * match the ISO PNG specification and to avoid relying on the C locale
+ * interpretation of character values.
+ *
+ * Prior to 1.5.6 these constants were strings, as of 1.5.6 png_uint_32 values
+ * are computed and a new macro (PNG_STRING_FROM_CHUNK) added to allow a string
+ * to be generated if required.
+ *
+ * PNG_32b correctly produces a value shifted by up to 24 bits, even on
+ * architectures where (int) is only 16 bits.
+ */
+#define PNG_32b(b,s) ((png_uint_32)(b) << (s))
+#define PNG_U32(b1,b2,b3,b4) \
+ (PNG_32b(b1,24) | PNG_32b(b2,16) | PNG_32b(b3,8) | PNG_32b(b4,0))
+
+/* Constants for known chunk types.
+ *
+ * MAINTAINERS: If you need to add a chunk, define the name here.
+ * For historical reasons these constants have the form png_<name>; i.e.
+ * the prefix is lower case. Please use decimal values as the parameters to
+ * match the ISO PNG specification and to avoid relying on the C locale
+ * interpretation of character values. Please keep the list sorted.
+ *
+ * Notice that PNG_U32 is used to define a 32-bit value for the 4 byte chunk
+ * type. In fact the specification does not express chunk types this way,
+ * however using a 32-bit value means that the chunk type can be read from the
+ * stream using exactly the same code as used for a 32-bit unsigned value and
+ * can be examined far more efficiently (using one arithmetic compare).
+ *
+ * Prior to 1.5.6 the chunk type constants were expressed as C strings. The
+ * libpng API still uses strings for 'unknown' chunks and a macro,
+ * PNG_STRING_FROM_CHUNK, allows a string to be generated if required. Notice
+ * that for portable code numeric values must still be used; the string "IHDR"
+ * is not portable and neither is PNG_U32('I', 'H', 'D', 'R').
+ *
+ * In 1.7.0 the definitions will be made public in png.h to avoid having to
+ * duplicate the same definitions in application code.
+ */
+#define png_IDAT PNG_U32( 73, 68, 65, 84)
+#define png_IEND PNG_U32( 73, 69, 78, 68)
+#define png_IHDR PNG_U32( 73, 72, 68, 82)
+#define png_PLTE PNG_U32( 80, 76, 84, 69)
+#define png_bKGD PNG_U32( 98, 75, 71, 68)
+#define png_cHRM PNG_U32( 99, 72, 82, 77)
+#define png_fRAc PNG_U32(102, 82, 65, 99) /* registered, not defined */
+#define png_gAMA PNG_U32(103, 65, 77, 65)
+#define png_gIFg PNG_U32(103, 73, 70, 103)
+#define png_gIFt PNG_U32(103, 73, 70, 116) /* deprecated */
+#define png_gIFx PNG_U32(103, 73, 70, 120)
+#define png_hIST PNG_U32(104, 73, 83, 84)
+#define png_iCCP PNG_U32(105, 67, 67, 80)
+#define png_iTXt PNG_U32(105, 84, 88, 116)
+#define png_oFFs PNG_U32(111, 70, 70, 115)
+#define png_pCAL PNG_U32(112, 67, 65, 76)
+#define png_pHYs PNG_U32(112, 72, 89, 115)
+#define png_sBIT PNG_U32(115, 66, 73, 84)
+#define png_sCAL PNG_U32(115, 67, 65, 76)
+#define png_sPLT PNG_U32(115, 80, 76, 84)
+#define png_sRGB PNG_U32(115, 82, 71, 66)
+#define png_sTER PNG_U32(115, 84, 69, 82)
+#define png_tEXt PNG_U32(116, 69, 88, 116)
+#define png_tIME PNG_U32(116, 73, 77, 69)
+#define png_tRNS PNG_U32(116, 82, 78, 83)
+#define png_zTXt PNG_U32(122, 84, 88, 116)
+
+/* The following will work on (signed char*) strings, whereas the get_uint_32
+ * macro will fail on top-bit-set values because of the sign extension.
+ */
+#define PNG_CHUNK_FROM_STRING(s)\
+ PNG_U32(0xff & (s)[0], 0xff & (s)[1], 0xff & (s)[2], 0xff & (s)[3])
+
+/* This uses (char), not (png_byte) to avoid warnings on systems where (char) is
+ * signed and the argument is a (char[]) This macro will fail miserably on
+ * systems where (char) is more than 8 bits.
+ */
+#define PNG_STRING_FROM_CHUNK(s,c)\
+ (void)(((char*)(s))[0]=(char)(((c)>>24) & 0xff), \
+ ((char*)(s))[1]=(char)(((c)>>16) & 0xff),\
+ ((char*)(s))[2]=(char)(((c)>>8) & 0xff), \
+ ((char*)(s))[3]=(char)((c & 0xff)))
+
+/* Do the same but terminate with a null character. */
+#define PNG_CSTRING_FROM_CHUNK(s,c)\
+ (void)(PNG_STRING_FROM_CHUNK(s,c), ((char*)(s))[4] = 0)
+
+/* Test on flag values as defined in the spec (section 5.4): */
+#define PNG_CHUNK_ANCILLARY(c) (1 & ((c) >> 29))
+#define PNG_CHUNK_CRITICAL(c) (!PNG_CHUNK_ANCILLARY(c))
+#define PNG_CHUNK_PRIVATE(c) (1 & ((c) >> 21))
+#define PNG_CHUNK_RESERVED(c) (1 & ((c) >> 13))
+#define PNG_CHUNK_SAFE_TO_COPY(c) (1 & ((c) >> 5))
+
+/* Gamma values (new at libpng-1.5.4): */
+#define PNG_GAMMA_MAC_OLD 151724 /* Assume '1.8' is really 2.2/1.45! */
+#define PNG_GAMMA_MAC_INVERSE 65909
+#define PNG_GAMMA_sRGB_INVERSE 45455
+
+/* Almost everything below is C specific; the #defines above can be used in
+ * non-C code (so long as it is C-preprocessed) the rest of this stuff cannot.
+ */
+#ifndef PNG_VERSION_INFO_ONLY
+
+#include "pngstruct.h"
+#include "pnginfo.h"
+
+/* Validate the include paths - the include path used to generate pnglibconf.h
+ * must match that used in the build, or we must be using pnglibconf.h.prebuilt:
+ */
+#if PNG_ZLIB_VERNUM != 0 && PNG_ZLIB_VERNUM != ZLIB_VERNUM
+# error ZLIB_VERNUM != PNG_ZLIB_VERNUM \
+ "-I (include path) error: see the notes in pngpriv.h"
+ /* This means that when pnglibconf.h was built the copy of zlib.h that it
+ * used is not the same as the one being used here. Because the build of
+ * libpng makes decisions to use inflateInit2 and inflateReset2 based on the
+ * zlib version number and because this affects handling of certain broken
+ * PNG files the -I directives must match.
+ *
+ * The most likely explanation is that you passed a -I in CFLAGS. This will
+ * not work; all the preprocessor directories and in particular all the -I
+ * directives must be in CPPFLAGS.
+ */
+#endif
+
+/* This is used for 16 bit gamma tables -- only the top level pointers are
+ * const; this could be changed:
+ */
+typedef const png_uint_16p * png_const_uint_16pp;
+
+/* Added to libpng-1.5.7: sRGB conversion tables */
+#if defined(PNG_SIMPLIFIED_READ_SUPPORTED) ||\
+ defined(PNG_SIMPLIFIED_WRITE_SUPPORTED)
+#ifdef PNG_SIMPLIFIED_READ_SUPPORTED
+PNG_INTERNAL_DATA(const png_uint_16, png_sRGB_table, [256]);
+ /* Convert from an sRGB encoded value 0..255 to a 16-bit linear value,
+ * 0..65535. This table gives the closest 16-bit answers (no errors).
+ */
+#endif
+
+PNG_INTERNAL_DATA(const png_uint_16, png_sRGB_base, [512]);
+PNG_INTERNAL_DATA(const png_byte, png_sRGB_delta, [512]);
+
+#define PNG_sRGB_FROM_LINEAR(linear) \
+ ((png_byte)(0xff & ((png_sRGB_base[(linear)>>15] \
+ + ((((linear) & 0x7fff)*png_sRGB_delta[(linear)>>15])>>12)) >> 8)))
+ /* Given a value 'linear' in the range 0..255*65535 calculate the 8-bit sRGB
+ * encoded value with maximum error 0.646365. Note that the input is not a
+ * 16-bit value; it has been multiplied by 255! */
+#endif /* SIMPLIFIED_READ/WRITE */
+
+
+/* Inhibit C++ name-mangling for libpng functions but not for system calls. */
+#ifdef __cplusplus
+extern "C" {
+#endif /* __cplusplus */
+
+/* Internal functions; these are not exported from a DLL however because they
+ * are used within several of the C source files they have to be C extern.
+ *
+ * All of these functions must be declared with PNG_INTERNAL_FUNCTION.
+ */
+
+/* Zlib support */
+#define PNG_UNEXPECTED_ZLIB_RETURN (-7)
+PNG_INTERNAL_FUNCTION(void, png_zstream_error,(png_structrp png_ptr, int ret),
+ PNG_EMPTY);
+ /* Used by the zlib handling functions to ensure that z_stream::msg is always
+ * set before they return.
+ */
+
+#ifdef PNG_WRITE_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_free_buffer_list,(png_structrp png_ptr,
+ png_compression_bufferp *list),PNG_EMPTY);
+ /* Free the buffer list used by the compressed write code. */
+#endif
+
+#if defined(PNG_FLOATING_POINT_SUPPORTED) && \
+ !defined(PNG_FIXED_POINT_MACRO_SUPPORTED) && \
+ (defined(PNG_gAMA_SUPPORTED) || defined(PNG_cHRM_SUPPORTED) || \
+ defined(PNG_sCAL_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED) || \
+ defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)) || \
+ (defined(PNG_sCAL_SUPPORTED) && \
+ defined(PNG_FLOATING_ARITHMETIC_SUPPORTED))
+PNG_INTERNAL_FUNCTION(png_fixed_point,png_fixed,(png_const_structrp png_ptr,
+ double fp, png_const_charp text),PNG_EMPTY);
+#endif
+
+/* Check the user version string for compatibility, returns false if the version
+ * numbers aren't compatible.
+ */
+PNG_INTERNAL_FUNCTION(int,png_user_version_check,(png_structrp png_ptr,
+ png_const_charp user_png_ver),PNG_EMPTY);
+
+/* Internal base allocator - no messages, NULL on failure to allocate. This
+ * does, however, call the application provided allocator and that could call
+ * png_error (although that would be a bug in the application implementation.)
+ */
+PNG_INTERNAL_FUNCTION(png_voidp,png_malloc_base,(png_const_structrp png_ptr,
+ png_alloc_size_t size),PNG_ALLOCATED);
+
+#if defined(PNG_TEXT_SUPPORTED) || defined(PNG_sPLT_SUPPORTED) ||\
+ defined(PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED)
+/* Internal array allocator, outputs no error or warning messages on failure,
+ * just returns NULL.
+ */
+PNG_INTERNAL_FUNCTION(png_voidp,png_malloc_array,(png_const_structrp png_ptr,
+ int nelements, size_t element_size),PNG_ALLOCATED);
+
+/* The same but an existing array is extended by add_elements. This function
+ * also memsets the new elements to 0 and copies the old elements. The old
+ * array is not freed or altered.
+ */
+PNG_INTERNAL_FUNCTION(png_voidp,png_realloc_array,(png_const_structrp png_ptr,
+ png_const_voidp array, int old_elements, int add_elements,
+ size_t element_size),PNG_ALLOCATED);
+#endif /* text, sPLT or unknown chunks */
+
+/* Magic to create a struct when there is no struct to call the user supplied
+ * memory allocators. Because error handling has not been set up the memory
+ * handlers can't safely call png_error, but this is an obscure and undocumented
+ * restriction so libpng has to assume that the 'free' handler, at least, might
+ * call png_error.
+ */
+PNG_INTERNAL_FUNCTION(png_structp,png_create_png_struct,
+ (png_const_charp user_png_ver, png_voidp error_ptr, png_error_ptr error_fn,
+ png_error_ptr warn_fn, png_voidp mem_ptr, png_malloc_ptr malloc_fn,
+ png_free_ptr free_fn),PNG_ALLOCATED);
+
+/* Free memory from internal libpng struct */
+PNG_INTERNAL_FUNCTION(void,png_destroy_png_struct,(png_structrp png_ptr),
+ PNG_EMPTY);
+
+/* Free an allocated jmp_buf (always succeeds) */
+PNG_INTERNAL_FUNCTION(void,png_free_jmpbuf,(png_structrp png_ptr),PNG_EMPTY);
+
+/* Function to allocate memory for zlib. PNGAPI is disallowed. */
+PNG_INTERNAL_FUNCTION(voidpf,png_zalloc,(voidpf png_ptr, uInt items, uInt size),
+ PNG_ALLOCATED);
+
+/* Function to free memory for zlib. PNGAPI is disallowed. */
+PNG_INTERNAL_FUNCTION(void,png_zfree,(voidpf png_ptr, voidpf ptr),PNG_EMPTY);
+
+/* Next four functions are used internally as callbacks. PNGCBAPI is required
+ * but not PNG_EXPORT. PNGAPI added at libpng version 1.2.3, changed to
+ * PNGCBAPI at 1.5.0
+ */
+
+PNG_INTERNAL_FUNCTION(void PNGCBAPI,png_default_read_data,(png_structp png_ptr,
+ png_bytep data, png_size_t length),PNG_EMPTY);
+
+#ifdef PNG_PROGRESSIVE_READ_SUPPORTED
+PNG_INTERNAL_FUNCTION(void PNGCBAPI,png_push_fill_buffer,(png_structp png_ptr,
+ png_bytep buffer, png_size_t length),PNG_EMPTY);
+#endif
+
+PNG_INTERNAL_FUNCTION(void PNGCBAPI,png_default_write_data,(png_structp png_ptr,
+ png_bytep data, png_size_t length),PNG_EMPTY);
+
+#ifdef PNG_WRITE_FLUSH_SUPPORTED
+# ifdef PNG_STDIO_SUPPORTED
+PNG_INTERNAL_FUNCTION(void PNGCBAPI,png_default_flush,(png_structp png_ptr),
+ PNG_EMPTY);
+# endif
+#endif
+
+/* Reset the CRC variable */
+PNG_INTERNAL_FUNCTION(void,png_reset_crc,(png_structrp png_ptr),PNG_EMPTY);
+
+/* Write the "data" buffer to whatever output you are using */
+PNG_INTERNAL_FUNCTION(void,png_write_data,(png_structrp png_ptr,
+ png_const_bytep data, png_size_t length),PNG_EMPTY);
+
+/* Read and check the PNG file signature */
+PNG_INTERNAL_FUNCTION(void,png_read_sig,(png_structrp png_ptr,
+ png_inforp info_ptr),PNG_EMPTY);
+
+/* Read the chunk header (length + type name) */
+PNG_INTERNAL_FUNCTION(png_uint_32,png_read_chunk_header,(png_structrp png_ptr),
+ PNG_EMPTY);
+
+/* Read data from whatever input you are using into the "data" buffer */
+PNG_INTERNAL_FUNCTION(void,png_read_data,(png_structrp png_ptr, png_bytep data,
+ png_size_t length),PNG_EMPTY);
+
+/* Read bytes into buf, and update png_ptr->crc */
+PNG_INTERNAL_FUNCTION(void,png_crc_read,(png_structrp png_ptr, png_bytep buf,
+ png_uint_32 length),PNG_EMPTY);
+
+/* Read "skip" bytes, read the file crc, and (optionally) verify png_ptr->crc */
+PNG_INTERNAL_FUNCTION(int,png_crc_finish,(png_structrp png_ptr,
+ png_uint_32 skip),PNG_EMPTY);
+
+/* Read the CRC from the file and compare it to the libpng calculated CRC */
+PNG_INTERNAL_FUNCTION(int,png_crc_error,(png_structrp png_ptr),PNG_EMPTY);
+
+/* Calculate the CRC over a section of data. Note that we are only
+ * passing a maximum of 64K on systems that have this as a memory limit,
+ * since this is the maximum buffer size we can specify.
+ */
+PNG_INTERNAL_FUNCTION(void,png_calculate_crc,(png_structrp png_ptr,
+ png_const_bytep ptr, png_size_t length),PNG_EMPTY);
+
+#ifdef PNG_WRITE_FLUSH_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_flush,(png_structrp png_ptr),PNG_EMPTY);
+#endif
+
+/* Write various chunks */
+
+/* Write the IHDR chunk, and update the png_struct with the necessary
+ * information.
+ */
+PNG_INTERNAL_FUNCTION(void,png_write_IHDR,(png_structrp png_ptr,
+ png_uint_32 width, png_uint_32 height, int bit_depth, int color_type,
+ int compression_method, int filter_method, int interlace_method),PNG_EMPTY);
+
+PNG_INTERNAL_FUNCTION(void,png_write_PLTE,(png_structrp png_ptr,
+ png_const_colorp palette, png_uint_32 num_pal),PNG_EMPTY);
+
+PNG_INTERNAL_FUNCTION(void,png_compress_IDAT,(png_structrp png_ptr,
+ png_const_bytep row_data, png_alloc_size_t row_data_length, int flush),
+ PNG_EMPTY);
+
+PNG_INTERNAL_FUNCTION(void,png_write_IEND,(png_structrp png_ptr),PNG_EMPTY);
+
+#ifdef PNG_WRITE_gAMA_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_write_gAMA_fixed,(png_structrp png_ptr,
+ png_fixed_point file_gamma),PNG_EMPTY);
+#endif
+
+#ifdef PNG_WRITE_sBIT_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_write_sBIT,(png_structrp png_ptr,
+ png_const_color_8p sbit, int color_type),PNG_EMPTY);
+#endif
+
+#ifdef PNG_WRITE_cHRM_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_write_cHRM_fixed,(png_structrp png_ptr,
+ const png_xy *xy), PNG_EMPTY);
+ /* The xy value must have been previously validated */
+#endif
+
+#ifdef PNG_WRITE_sRGB_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_write_sRGB,(png_structrp png_ptr,
+ int intent),PNG_EMPTY);
+#endif
+
+#ifdef PNG_WRITE_iCCP_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_write_iCCP,(png_structrp png_ptr,
+ png_const_charp name, png_const_bytep profile), PNG_EMPTY);
+ /* The profile must have been previously validated for correctness, the
+ * length comes from the first four bytes. Only the base, deflate,
+ * compression is supported.
+ */
+#endif
+
+#ifdef PNG_WRITE_sPLT_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_write_sPLT,(png_structrp png_ptr,
+ png_const_sPLT_tp palette),PNG_EMPTY);
+#endif
+
+#ifdef PNG_WRITE_tRNS_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_write_tRNS,(png_structrp png_ptr,
+ png_const_bytep trans, png_const_color_16p values, int number,
+ int color_type),PNG_EMPTY);
+#endif
+
+#ifdef PNG_WRITE_bKGD_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_write_bKGD,(png_structrp png_ptr,
+ png_const_color_16p values, int color_type),PNG_EMPTY);
+#endif
+
+#ifdef PNG_WRITE_hIST_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_write_hIST,(png_structrp png_ptr,
+ png_const_uint_16p hist, int num_hist),PNG_EMPTY);
+#endif
+
+/* Chunks that have keywords */
+#ifdef PNG_WRITE_tEXt_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_write_tEXt,(png_structrp png_ptr,
+ png_const_charp key, png_const_charp text, png_size_t text_len),PNG_EMPTY);
+#endif
+
+#ifdef PNG_WRITE_zTXt_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_write_zTXt,(png_structrp png_ptr, png_const_charp
+ key, png_const_charp text, int compression),PNG_EMPTY);
+#endif
+
+#ifdef PNG_WRITE_iTXt_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_write_iTXt,(png_structrp png_ptr,
+ int compression, png_const_charp key, png_const_charp lang,
+ png_const_charp lang_key, png_const_charp text),PNG_EMPTY);
+#endif
+
+#ifdef PNG_TEXT_SUPPORTED /* Added at version 1.0.14 and 1.2.4 */
+PNG_INTERNAL_FUNCTION(int,png_set_text_2,(png_const_structrp png_ptr,
+ png_inforp info_ptr, png_const_textp text_ptr, int num_text),PNG_EMPTY);
+#endif
+
+#ifdef PNG_WRITE_oFFs_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_write_oFFs,(png_structrp png_ptr,
+ png_int_32 x_offset, png_int_32 y_offset, int unit_type),PNG_EMPTY);
+#endif
+
+#ifdef PNG_WRITE_pCAL_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_write_pCAL,(png_structrp png_ptr,
+ png_charp purpose, png_int_32 X0, png_int_32 X1, int type, int nparams,
+ png_const_charp units, png_charpp params),PNG_EMPTY);
+#endif
+
+#ifdef PNG_WRITE_pHYs_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_write_pHYs,(png_structrp png_ptr,
+ png_uint_32 x_pixels_per_unit, png_uint_32 y_pixels_per_unit,
+ int unit_type),PNG_EMPTY);
+#endif
+
+#ifdef PNG_WRITE_tIME_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_write_tIME,(png_structrp png_ptr,
+ png_const_timep mod_time),PNG_EMPTY);
+#endif
+
+#ifdef PNG_WRITE_sCAL_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_write_sCAL_s,(png_structrp png_ptr,
+ int unit, png_const_charp width, png_const_charp height),PNG_EMPTY);
+#endif
+
+/* Called when finished processing a row of data */
+PNG_INTERNAL_FUNCTION(void,png_write_finish_row,(png_structrp png_ptr),
+ PNG_EMPTY);
+
+/* Internal use only. Called before first row of data */
+PNG_INTERNAL_FUNCTION(void,png_write_start_row,(png_structrp png_ptr),
+ PNG_EMPTY);
+
+/* Combine a row of data, dealing with alpha, etc. if requested. 'row' is an
+ * array of png_ptr->width pixels. If the image is not interlaced or this
+ * is the final pass this just does a memcpy, otherwise the "display" flag
+ * is used to determine whether to copy pixels that are not in the current pass.
+ *
+ * Because 'png_do_read_interlace' (below) replicates pixels this allows this
+ * function to achieve the documented 'blocky' appearance during interlaced read
+ * if display is 1 and the 'sparkle' appearance, where existing pixels in 'row'
+ * are not changed if they are not in the current pass, when display is 0.
+ *
+ * 'display' must be 0 or 1, otherwise the memcpy will be done regardless.
+ *
+ * The API always reads from the png_struct row buffer and always assumes that
+ * it is full width (png_do_read_interlace has already been called.)
+ *
+ * This function is only ever used to write to row buffers provided by the
+ * caller of the relevant libpng API and the row must have already been
+ * transformed by the read transformations.
+ *
+ * The PNG_USE_COMPILE_TIME_MASKS option causes generation of pre-computed
+ * bitmasks for use within the code, otherwise runtime generated masks are used.
+ * The default is compile time masks.
+ */
+#ifndef PNG_USE_COMPILE_TIME_MASKS
+# define PNG_USE_COMPILE_TIME_MASKS 1
+#endif
+PNG_INTERNAL_FUNCTION(void,png_combine_row,(png_const_structrp png_ptr,
+ png_bytep row, int display),PNG_EMPTY);
+
+#ifdef PNG_READ_INTERLACING_SUPPORTED
+/* Expand an interlaced row: the 'row_info' describes the pass data that has
+ * been read in and must correspond to the pixels in 'row', the pixels are
+ * expanded (moved apart) in 'row' to match the final layout, when doing this
+ * the pixels are *replicated* to the intervening space. This is essential for
+ * the correct operation of png_combine_row, above.
+ */
+PNG_INTERNAL_FUNCTION(void,png_do_read_interlace,(png_row_infop row_info,
+ png_bytep row, int pass, png_uint_32 transformations),PNG_EMPTY);
+#endif
+
+/* GRR TO DO (2.0 or whenever): simplify other internal calling interfaces */
+
+#ifdef PNG_WRITE_INTERLACING_SUPPORTED
+/* Grab pixels out of a row for an interlaced pass */
+PNG_INTERNAL_FUNCTION(void,png_do_write_interlace,(png_row_infop row_info,
+ png_bytep row, int pass),PNG_EMPTY);
+#endif
+
+/* Unfilter a row: check the filter value before calling this, there is no point
+ * calling it for PNG_FILTER_VALUE_NONE.
+ */
+PNG_INTERNAL_FUNCTION(void,png_read_filter_row,(png_structrp pp, png_row_infop
+ row_info, png_bytep row, png_const_bytep prev_row, int filter),PNG_EMPTY);
+
+PNG_INTERNAL_FUNCTION(void,png_read_filter_row_up_neon,(png_row_infop row_info,
+ png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_read_filter_row_sub3_neon,(png_row_infop
+ row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_read_filter_row_sub4_neon,(png_row_infop
+ row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_read_filter_row_avg3_neon,(png_row_infop
+ row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_read_filter_row_avg4_neon,(png_row_infop
+ row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_read_filter_row_paeth3_neon,(png_row_infop
+ row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_read_filter_row_paeth4_neon,(png_row_infop
+ row_info, png_bytep row, png_const_bytep prev_row),PNG_EMPTY);
+
+/* Choose the best filter to use and filter the row data */
+PNG_INTERNAL_FUNCTION(void,png_write_find_filter,(png_structrp png_ptr,
+ png_row_infop row_info),PNG_EMPTY);
+
+#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_read_IDAT_data,(png_structrp png_ptr,
+ png_bytep output, png_alloc_size_t avail_out),PNG_EMPTY);
+ /* Read 'avail_out' bytes of data from the IDAT stream. If the output buffer
+ * is NULL the function checks, instead, for the end of the stream. In this
+ * case a benign error will be issued if the stream end is not found or if
+ * extra data has to be consumed.
+ */
+PNG_INTERNAL_FUNCTION(void,png_read_finish_IDAT,(png_structrp png_ptr),
+ PNG_EMPTY);
+ /* This cleans up when the IDAT LZ stream does not end when the last image
+ * byte is read; there is still some pending input.
+ */
+
+PNG_INTERNAL_FUNCTION(void,png_read_finish_row,(png_structrp png_ptr),
+ PNG_EMPTY);
+ /* Finish a row while reading, dealing with interlacing passes, etc. */
+#endif /* SEQUENTIAL_READ */
+
+/* Initialize the row buffers, etc. */
+PNG_INTERNAL_FUNCTION(void,png_read_start_row,(png_structrp png_ptr),PNG_EMPTY);
+
+#ifdef PNG_READ_TRANSFORMS_SUPPORTED
+/* Optional call to update the users info structure */
+PNG_INTERNAL_FUNCTION(void,png_read_transform_info,(png_structrp png_ptr,
+ png_inforp info_ptr),PNG_EMPTY);
+#endif
+
+/* Shared transform functions, defined in pngtran.c */
+#if defined(PNG_WRITE_FILLER_SUPPORTED) || \
+ defined(PNG_READ_STRIP_ALPHA_SUPPORTED)
+PNG_INTERNAL_FUNCTION(void,png_do_strip_channel,(png_row_infop row_info,
+ png_bytep row, int at_start),PNG_EMPTY);
+#endif
+
+#ifdef PNG_16BIT_SUPPORTED
+#if defined(PNG_READ_SWAP_SUPPORTED) || defined(PNG_WRITE_SWAP_SUPPORTED)
+PNG_INTERNAL_FUNCTION(void,png_do_swap,(png_row_infop row_info,
+ png_bytep row),PNG_EMPTY);
+#endif
+#endif
+
+#if defined(PNG_READ_PACKSWAP_SUPPORTED) || \
+ defined(PNG_WRITE_PACKSWAP_SUPPORTED)
+PNG_INTERNAL_FUNCTION(void,png_do_packswap,(png_row_infop row_info,
+ png_bytep row),PNG_EMPTY);
+#endif
+
+#if defined(PNG_READ_INVERT_SUPPORTED) || defined(PNG_WRITE_INVERT_SUPPORTED)
+PNG_INTERNAL_FUNCTION(void,png_do_invert,(png_row_infop row_info,
+ png_bytep row),PNG_EMPTY);
+#endif
+
+#if defined(PNG_READ_BGR_SUPPORTED) || defined(PNG_WRITE_BGR_SUPPORTED)
+PNG_INTERNAL_FUNCTION(void,png_do_bgr,(png_row_infop row_info,
+ png_bytep row),PNG_EMPTY);
+#endif
+
+/* The following decodes the appropriate chunks, and does error correction,
+ * then calls the appropriate callback for the chunk if it is valid.
+ */
+
+/* Decode the IHDR chunk */
+PNG_INTERNAL_FUNCTION(void,png_handle_IHDR,(png_structrp png_ptr,
+ png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_handle_PLTE,(png_structrp png_ptr,
+ png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_handle_IEND,(png_structrp png_ptr,
+ png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
+
+#ifdef PNG_READ_bKGD_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_handle_bKGD,(png_structrp png_ptr,
+ png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
+#endif
+
+#ifdef PNG_READ_cHRM_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_handle_cHRM,(png_structrp png_ptr,
+ png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
+#endif
+
+#ifdef PNG_READ_gAMA_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_handle_gAMA,(png_structrp png_ptr,
+ png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
+#endif
+
+#ifdef PNG_READ_hIST_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_handle_hIST,(png_structrp png_ptr,
+ png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
+#endif
+
+#ifdef PNG_READ_iCCP_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_handle_iCCP,(png_structrp png_ptr,
+ png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
+#endif /* READ_iCCP */
+
+#ifdef PNG_READ_iTXt_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_handle_iTXt,(png_structrp png_ptr,
+ png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
+#endif
+
+#ifdef PNG_READ_oFFs_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_handle_oFFs,(png_structrp png_ptr,
+ png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
+#endif
+
+#ifdef PNG_READ_pCAL_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_handle_pCAL,(png_structrp png_ptr,
+ png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
+#endif
+
+#ifdef PNG_READ_pHYs_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_handle_pHYs,(png_structrp png_ptr,
+ png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
+#endif
+
+#ifdef PNG_READ_sBIT_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_handle_sBIT,(png_structrp png_ptr,
+ png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
+#endif
+
+#ifdef PNG_READ_sCAL_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_handle_sCAL,(png_structrp png_ptr,
+ png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
+#endif
+
+#ifdef PNG_READ_sPLT_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_handle_sPLT,(png_structrp png_ptr,
+ png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
+#endif /* READ_sPLT */
+
+#ifdef PNG_READ_sRGB_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_handle_sRGB,(png_structrp png_ptr,
+ png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
+#endif
+
+#ifdef PNG_READ_tEXt_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_handle_tEXt,(png_structrp png_ptr,
+ png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
+#endif
+
+#ifdef PNG_READ_tIME_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_handle_tIME,(png_structrp png_ptr,
+ png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
+#endif
+
+#ifdef PNG_READ_tRNS_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_handle_tRNS,(png_structrp png_ptr,
+ png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
+#endif
+
+#ifdef PNG_READ_zTXt_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_handle_zTXt,(png_structrp png_ptr,
+ png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
+#endif
+
+PNG_INTERNAL_FUNCTION(void,png_check_chunk_name,(png_structrp png_ptr,
+ png_uint_32 chunk_name),PNG_EMPTY);
+
+PNG_INTERNAL_FUNCTION(void,png_handle_unknown,(png_structrp png_ptr,
+ png_inforp info_ptr, png_uint_32 length, int keep),PNG_EMPTY);
+ /* This is the function that gets called for unknown chunks. The 'keep'
+ * argument is either non-zero for a known chunk that has been set to be
+ * handled as unknown or zero for an unknown chunk. By default the function
+ * just skips the chunk or errors out if it is critical.
+ */
+
+#if defined(PNG_READ_UNKNOWN_CHUNKS_SUPPORTED) ||\
+ defined(PNG_HANDLE_AS_UNKNOWN_SUPPORTED)
+PNG_INTERNAL_FUNCTION(int,png_chunk_unknown_handling,
+ (png_const_structrp png_ptr, png_uint_32 chunk_name),PNG_EMPTY);
+ /* Exactly as the API png_handle_as_unknown() except that the argument is a
+ * 32-bit chunk name, not a string.
+ */
+#endif /* READ_UNKNOWN_CHUNKS || HANDLE_AS_UNKNOWN */
+
+/* Handle the transformations for reading and writing */
+#ifdef PNG_READ_TRANSFORMS_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_do_read_transformations,(png_structrp png_ptr,
+ png_row_infop row_info),PNG_EMPTY);
+#endif
+#ifdef PNG_WRITE_TRANSFORMS_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_do_write_transformations,(png_structrp png_ptr,
+ png_row_infop row_info),PNG_EMPTY);
+#endif
+
+#ifdef PNG_READ_TRANSFORMS_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_init_read_transformations,(png_structrp png_ptr),
+ PNG_EMPTY);
+#endif
+
+#ifdef PNG_PROGRESSIVE_READ_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_push_read_chunk,(png_structrp png_ptr,
+ png_inforp info_ptr),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_push_read_sig,(png_structrp png_ptr,
+ png_inforp info_ptr),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_push_check_crc,(png_structrp png_ptr),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_push_crc_skip,(png_structrp png_ptr,
+ png_uint_32 length),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_push_crc_finish,(png_structrp png_ptr),
+ PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_push_save_buffer,(png_structrp png_ptr),
+ PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_push_restore_buffer,(png_structrp png_ptr,
+ png_bytep buffer, png_size_t buffer_length),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_push_read_IDAT,(png_structrp png_ptr),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_process_IDAT_data,(png_structrp png_ptr,
+ png_bytep buffer, png_size_t buffer_length),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_push_process_row,(png_structrp png_ptr),
+ PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_push_handle_unknown,(png_structrp png_ptr,
+ png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_push_have_info,(png_structrp png_ptr,
+ png_inforp info_ptr),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_push_have_end,(png_structrp png_ptr,
+ png_inforp info_ptr),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_push_have_row,(png_structrp png_ptr,
+ png_bytep row),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_push_read_end,(png_structrp png_ptr,
+ png_inforp info_ptr),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_process_some_data,(png_structrp png_ptr,
+ png_inforp info_ptr),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_read_push_finish_row,(png_structrp png_ptr),
+ PNG_EMPTY);
+# ifdef PNG_READ_tEXt_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_push_handle_tEXt,(png_structrp png_ptr,
+ png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_push_read_tEXt,(png_structrp png_ptr,
+ png_inforp info_ptr),PNG_EMPTY);
+# endif
+# ifdef PNG_READ_zTXt_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_push_handle_zTXt,(png_structrp png_ptr,
+ png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_push_read_zTXt,(png_structrp png_ptr,
+ png_inforp info_ptr),PNG_EMPTY);
+# endif
+# ifdef PNG_READ_iTXt_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_push_handle_iTXt,(png_structrp png_ptr,
+ png_inforp info_ptr, png_uint_32 length),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_push_read_iTXt,(png_structrp png_ptr,
+ png_inforp info_ptr),PNG_EMPTY);
+# endif
+
+#endif /* PROGRESSIVE_READ */
+
+/* Added at libpng version 1.6.0 */
+#ifdef PNG_GAMMA_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_colorspace_set_gamma,(png_const_structrp png_ptr,
+ png_colorspacerp colorspace, png_fixed_point gAMA), PNG_EMPTY);
+ /* Set the colorspace gamma with a value provided by the application or by
+ * the gAMA chunk on read. The value will override anything set by an ICC
+ * profile.
+ */
+
+PNG_INTERNAL_FUNCTION(void,png_colorspace_sync_info,(png_const_structrp png_ptr,
+ png_inforp info_ptr), PNG_EMPTY);
+ /* Synchronize the info 'valid' flags with the colorspace */
+
+PNG_INTERNAL_FUNCTION(void,png_colorspace_sync,(png_const_structrp png_ptr,
+ png_inforp info_ptr), PNG_EMPTY);
+ /* Copy the png_struct colorspace to the info_struct and call the above to
+ * synchronize the flags. Checks for NULL info_ptr and does nothing.
+ */
+#endif
+
+/* Added at libpng version 1.4.0 */
+#ifdef PNG_COLORSPACE_SUPPORTED
+/* These internal functions are for maintaining the colorspace structure within
+ * a png_info or png_struct (or, indeed, both).
+ */
+PNG_INTERNAL_FUNCTION(int,png_colorspace_set_chromaticities,
+ (png_const_structrp png_ptr, png_colorspacerp colorspace, const png_xy *xy,
+ int preferred), PNG_EMPTY);
+
+PNG_INTERNAL_FUNCTION(int,png_colorspace_set_endpoints,
+ (png_const_structrp png_ptr, png_colorspacerp colorspace, const png_XYZ *XYZ,
+ int preferred), PNG_EMPTY);
+
+#ifdef PNG_sRGB_SUPPORTED
+PNG_INTERNAL_FUNCTION(int,png_colorspace_set_sRGB,(png_const_structrp png_ptr,
+ png_colorspacerp colorspace, int intent), PNG_EMPTY);
+ /* This does set the colorspace gAMA and cHRM values too, but doesn't set the
+ * flags to write them, if it returns false there was a problem and an error
+ * message has already been output (but the colorspace may still need to be
+ * synced to record the invalid flag).
+ */
+#endif /* sRGB */
+
+#ifdef PNG_iCCP_SUPPORTED
+PNG_INTERNAL_FUNCTION(int,png_colorspace_set_ICC,(png_const_structrp png_ptr,
+ png_colorspacerp colorspace, png_const_charp name,
+ png_uint_32 profile_length, png_const_bytep profile, int color_type),
+ PNG_EMPTY);
+ /* The 'name' is used for information only */
+
+/* Routines for checking parts of an ICC profile. */
+PNG_INTERNAL_FUNCTION(int,png_icc_check_length,(png_const_structrp png_ptr,
+ png_colorspacerp colorspace, png_const_charp name,
+ png_uint_32 profile_length), PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(int,png_icc_check_header,(png_const_structrp png_ptr,
+ png_colorspacerp colorspace, png_const_charp name,
+ png_uint_32 profile_length,
+ png_const_bytep profile /* first 132 bytes only */, int color_type),
+ PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(int,png_icc_check_tag_table,(png_const_structrp png_ptr,
+ png_colorspacerp colorspace, png_const_charp name,
+ png_uint_32 profile_length,
+ png_const_bytep profile /* header plus whole tag table */), PNG_EMPTY);
+#ifdef PNG_sRGB_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_icc_set_sRGB,(
+ png_const_structrp png_ptr, png_colorspacerp colorspace,
+ png_const_bytep profile, uLong adler), PNG_EMPTY);
+ /* 'adler' is the Adler32 checksum of the uncompressed profile data. It may
+ * be zero to indicate that it is not available. It is used, if provided,
+ * as a fast check on the profile when checking to see if it is sRGB.
+ */
+#endif
+#endif /* iCCP */
+
+#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_colorspace_set_rgb_coefficients,
+ (png_structrp png_ptr), PNG_EMPTY);
+ /* Set the rgb_to_gray coefficients from the colorspace Y values */
+#endif /* READ_RGB_TO_GRAY */
+#endif /* COLORSPACE */
+
+/* Added at libpng version 1.4.0 */
+PNG_INTERNAL_FUNCTION(void,png_check_IHDR,(png_const_structrp png_ptr,
+ png_uint_32 width, png_uint_32 height, int bit_depth,
+ int color_type, int interlace_type, int compression_type,
+ int filter_type),PNG_EMPTY);
+
+/* Added at libpng version 1.5.10 */
+#if defined(PNG_READ_CHECK_FOR_INVALID_INDEX_SUPPORTED) || \
+ defined(PNG_WRITE_CHECK_FOR_INVALID_INDEX_SUPPORTED)
+PNG_INTERNAL_FUNCTION(void,png_do_check_palette_indexes,
+ (png_structrp png_ptr, png_row_infop row_info),PNG_EMPTY);
+#endif
+
+#if defined(PNG_FLOATING_POINT_SUPPORTED) && defined(PNG_ERROR_TEXT_SUPPORTED)
+PNG_INTERNAL_FUNCTION(void,png_fixed_error,(png_const_structrp png_ptr,
+ png_const_charp name),PNG_NORETURN);
+#endif
+
+/* Puts 'string' into 'buffer' at buffer[pos], taking care never to overwrite
+ * the end. Always leaves the buffer nul terminated. Never errors out (and
+ * there is no error code.)
+ */
+PNG_INTERNAL_FUNCTION(size_t,png_safecat,(png_charp buffer, size_t bufsize,
+ size_t pos, png_const_charp string),PNG_EMPTY);
+
+/* Various internal functions to handle formatted warning messages, currently
+ * only implemented for warnings.
+ */
+#if defined(PNG_WARNINGS_SUPPORTED) || defined(PNG_TIME_RFC1123_SUPPORTED)
+/* Utility to dump an unsigned value into a buffer, given a start pointer and
+ * and end pointer (which should point just *beyond* the end of the buffer!)
+ * Returns the pointer to the start of the formatted string. This utility only
+ * does unsigned values.
+ */
+PNG_INTERNAL_FUNCTION(png_charp,png_format_number,(png_const_charp start,
+ png_charp end, int format, png_alloc_size_t number),PNG_EMPTY);
+
+/* Convenience macro that takes an array: */
+#define PNG_FORMAT_NUMBER(buffer,format,number) \
+ png_format_number(buffer, buffer + (sizeof buffer), format, number)
+
+/* Suggested size for a number buffer (enough for 64 bits and a sign!) */
+#define PNG_NUMBER_BUFFER_SIZE 24
+
+/* These are the integer formats currently supported, the name is formed from
+ * the standard printf(3) format string.
+ */
+#define PNG_NUMBER_FORMAT_u 1 /* chose unsigned API! */
+#define PNG_NUMBER_FORMAT_02u 2
+#define PNG_NUMBER_FORMAT_d 1 /* chose signed API! */
+#define PNG_NUMBER_FORMAT_02d 2
+#define PNG_NUMBER_FORMAT_x 3
+#define PNG_NUMBER_FORMAT_02x 4
+#define PNG_NUMBER_FORMAT_fixed 5 /* choose the signed API */
+#endif
+
+#ifdef PNG_WARNINGS_SUPPORTED
+/* New defines and members adding in libpng-1.5.4 */
+# define PNG_WARNING_PARAMETER_SIZE 32
+# define PNG_WARNING_PARAMETER_COUNT 8 /* Maximum 9; see pngerror.c */
+
+/* An l-value of this type has to be passed to the APIs below to cache the
+ * values of the parameters to a formatted warning message.
+ */
+typedef char png_warning_parameters[PNG_WARNING_PARAMETER_COUNT][
+ PNG_WARNING_PARAMETER_SIZE];
+
+PNG_INTERNAL_FUNCTION(void,png_warning_parameter,(png_warning_parameters p,
+ int number, png_const_charp string),PNG_EMPTY);
+ /* Parameters are limited in size to PNG_WARNING_PARAMETER_SIZE characters,
+ * including the trailing '\0'.
+ */
+PNG_INTERNAL_FUNCTION(void,png_warning_parameter_unsigned,
+ (png_warning_parameters p, int number, int format, png_alloc_size_t value),
+ PNG_EMPTY);
+ /* Use png_alloc_size_t because it is an unsigned type as big as any we
+ * need to output. Use the following for a signed value.
+ */
+PNG_INTERNAL_FUNCTION(void,png_warning_parameter_signed,
+ (png_warning_parameters p, int number, int format, png_int_32 value),
+ PNG_EMPTY);
+
+PNG_INTERNAL_FUNCTION(void,png_formatted_warning,(png_const_structrp png_ptr,
+ png_warning_parameters p, png_const_charp message),PNG_EMPTY);
+ /* 'message' follows the X/Open approach of using @1, @2 to insert
+ * parameters previously supplied using the above functions. Errors in
+ * specifying the parameters will simply result in garbage substitutions.
+ */
+#endif
+
+#ifdef PNG_BENIGN_ERRORS_SUPPORTED
+/* Application errors (new in 1.6); use these functions (declared below) for
+ * errors in the parameters or order of API function calls on read. The
+ * 'warning' should be used for an error that can be handled completely; the
+ * 'error' for one which can be handled safely but which may lose application
+ * information or settings.
+ *
+ * By default these both result in a png_error call prior to release, while in a
+ * released version the 'warning' is just a warning. However if the application
+ * explicitly disables benign errors (explicitly permitting the code to lose
+ * information) they both turn into warnings.
+ *
+ * If benign errors aren't supported they end up as the corresponding base call
+ * (png_warning or png_error.)
+ */
+PNG_INTERNAL_FUNCTION(void,png_app_warning,(png_const_structrp png_ptr,
+ png_const_charp message),PNG_EMPTY);
+ /* The application provided invalid parameters to an API function or called
+ * an API function at the wrong time, libpng can completely recover.
+ */
+
+PNG_INTERNAL_FUNCTION(void,png_app_error,(png_const_structrp png_ptr,
+ png_const_charp message),PNG_EMPTY);
+ /* As above but libpng will ignore the call, or attempt some other partial
+ * recovery from the error.
+ */
+#else
+# define png_app_warning(pp,s) png_warning(pp,s)
+# define png_app_error(pp,s) png_error(pp,s)
+#endif
+
+PNG_INTERNAL_FUNCTION(void,png_chunk_report,(png_const_structrp png_ptr,
+ png_const_charp message, int error),PNG_EMPTY);
+ /* Report a recoverable issue in chunk data. On read this is used to report
+ * a problem found while reading a particular chunk and the
+ * png_chunk_benign_error or png_chunk_warning function is used as
+ * appropriate. On write this is used to report an error that comes from
+ * data set via an application call to a png_set_ API and png_app_error or
+ * png_app_warning is used as appropriate.
+ *
+ * The 'error' parameter must have one of the following values:
+ */
+#define PNG_CHUNK_WARNING 0 /* never an error */
+#define PNG_CHUNK_WRITE_ERROR 1 /* an error only on write */
+#define PNG_CHUNK_ERROR 2 /* always an error */
+
+/* ASCII to FP interfaces, currently only implemented if sCAL
+ * support is required.
+ */
+#if defined(PNG_sCAL_SUPPORTED)
+/* MAX_DIGITS is actually the maximum number of characters in an sCAL
+ * width or height, derived from the precision (number of significant
+ * digits - a build time settable option) and assumptions about the
+ * maximum ridiculous exponent.
+ */
+#define PNG_sCAL_MAX_DIGITS (PNG_sCAL_PRECISION+1/*.*/+1/*E*/+10/*exponent*/)
+
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_ascii_from_fp,(png_const_structrp png_ptr,
+ png_charp ascii, png_size_t size, double fp, unsigned int precision),
+ PNG_EMPTY);
+#endif /* FLOATING_POINT */
+
+#ifdef PNG_FIXED_POINT_SUPPORTED
+PNG_INTERNAL_FUNCTION(void,png_ascii_from_fixed,(png_const_structrp png_ptr,
+ png_charp ascii, png_size_t size, png_fixed_point fp),PNG_EMPTY);
+#endif /* FIXED_POINT */
+#endif /* sCAL */
+
+#if defined(PNG_sCAL_SUPPORTED) || defined(PNG_pCAL_SUPPORTED)
+/* An internal API to validate the format of a floating point number.
+ * The result is the index of the next character. If the number is
+ * not valid it will be the index of a character in the supposed number.
+ *
+ * The format of a number is defined in the PNG extensions specification
+ * and this API is strictly conformant to that spec, not anyone elses!
+ *
+ * The format as a regular expression is:
+ *
+ * [+-]?[0-9]+.?([Ee][+-]?[0-9]+)?
+ *
+ * or:
+ *
+ * [+-]?.[0-9]+(.[0-9]+)?([Ee][+-]?[0-9]+)?
+ *
+ * The complexity is that either integer or fraction must be present and the
+ * fraction is permitted to have no digits only if the integer is present.
+ *
+ * NOTE: The dangling E problem.
+ * There is a PNG valid floating point number in the following:
+ *
+ * PNG floating point numbers are not greedy.
+ *
+ * Working this out requires *TWO* character lookahead (because of the
+ * sign), the parser does not do this - it will fail at the 'r' - this
+ * doesn't matter for PNG sCAL chunk values, but it requires more care
+ * if the value were ever to be embedded in something more complex. Use
+ * ANSI-C strtod if you need the lookahead.
+ */
+/* State table for the parser. */
+#define PNG_FP_INTEGER 0 /* before or in integer */
+#define PNG_FP_FRACTION 1 /* before or in fraction */
+#define PNG_FP_EXPONENT 2 /* before or in exponent */
+#define PNG_FP_STATE 3 /* mask for the above */
+#define PNG_FP_SAW_SIGN 4 /* Saw +/- in current state */
+#define PNG_FP_SAW_DIGIT 8 /* Saw a digit in current state */
+#define PNG_FP_SAW_DOT 16 /* Saw a dot in current state */
+#define PNG_FP_SAW_E 32 /* Saw an E (or e) in current state */
+#define PNG_FP_SAW_ANY 60 /* Saw any of the above 4 */
+
+/* These three values don't affect the parser. They are set but not used.
+ */
+#define PNG_FP_WAS_VALID 64 /* Preceding substring is a valid fp number */
+#define PNG_FP_NEGATIVE 128 /* A negative number, including "-0" */
+#define PNG_FP_NONZERO 256 /* A non-zero value */
+#define PNG_FP_STICKY 448 /* The above three flags */
+
+/* This is available for the caller to store in 'state' if required. Do not
+ * call the parser after setting it (the parser sometimes clears it.)
+ */
+#define PNG_FP_INVALID 512 /* Available for callers as a distinct value */
+
+/* Result codes for the parser (boolean - true meants ok, false means
+ * not ok yet.)
+ */
+#define PNG_FP_MAYBE 0 /* The number may be valid in the future */
+#define PNG_FP_OK 1 /* The number is valid */
+
+/* Tests on the sticky non-zero and negative flags. To pass these checks
+ * the state must also indicate that the whole number is valid - this is
+ * achieved by testing PNG_FP_SAW_DIGIT (see the implementation for why this
+ * is equivalent to PNG_FP_OK above.)
+ */
+#define PNG_FP_NZ_MASK (PNG_FP_SAW_DIGIT | PNG_FP_NEGATIVE | PNG_FP_NONZERO)
+ /* NZ_MASK: the string is valid and a non-zero negative value */
+#define PNG_FP_Z_MASK (PNG_FP_SAW_DIGIT | PNG_FP_NONZERO)
+ /* Z MASK: the string is valid and a non-zero value. */
+ /* PNG_FP_SAW_DIGIT: the string is valid. */
+#define PNG_FP_IS_ZERO(state) (((state) & PNG_FP_Z_MASK) == PNG_FP_SAW_DIGIT)
+#define PNG_FP_IS_POSITIVE(state) (((state) & PNG_FP_NZ_MASK) == PNG_FP_Z_MASK)
+#define PNG_FP_IS_NEGATIVE(state) (((state) & PNG_FP_NZ_MASK) == PNG_FP_NZ_MASK)
+
+/* The actual parser. This can be called repeatedly. It updates
+ * the index into the string and the state variable (which must
+ * be initialized to 0). It returns a result code, as above. There
+ * is no point calling the parser any more if it fails to advance to
+ * the end of the string - it is stuck on an invalid character (or
+ * terminated by '\0').
+ *
+ * Note that the pointer will consume an E or even an E+ and then leave
+ * a 'maybe' state even though a preceding integer.fraction is valid.
+ * The PNG_FP_WAS_VALID flag indicates that a preceding substring was
+ * a valid number. It's possible to recover from this by calling
+ * the parser again (from the start, with state 0) but with a string
+ * that omits the last character (i.e. set the size to the index of
+ * the problem character.) This has not been tested within libpng.
+ */
+PNG_INTERNAL_FUNCTION(int,png_check_fp_number,(png_const_charp string,
+ png_size_t size, int *statep, png_size_tp whereami),PNG_EMPTY);
+
+/* This is the same but it checks a complete string and returns true
+ * only if it just contains a floating point number. As of 1.5.4 this
+ * function also returns the state at the end of parsing the number if
+ * it was valid (otherwise it returns 0.) This can be used for testing
+ * for negative or zero values using the sticky flag.
+ */
+PNG_INTERNAL_FUNCTION(int,png_check_fp_string,(png_const_charp string,
+ png_size_t size),PNG_EMPTY);
+#endif /* pCAL || sCAL */
+
+#if defined(PNG_GAMMA_SUPPORTED) ||\
+ defined(PNG_INCH_CONVERSIONS_SUPPORTED) || defined(PNG_READ_pHYs_SUPPORTED)
+/* Added at libpng version 1.5.0 */
+/* This is a utility to provide a*times/div (rounded) and indicate
+ * if there is an overflow. The result is a boolean - false (0)
+ * for overflow, true (1) if no overflow, in which case *res
+ * holds the result.
+ */
+PNG_INTERNAL_FUNCTION(int,png_muldiv,(png_fixed_point_p res, png_fixed_point a,
+ png_int_32 multiplied_by, png_int_32 divided_by),PNG_EMPTY);
+#endif
+
+#if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_INCH_CONVERSIONS_SUPPORTED)
+/* Same deal, but issue a warning on overflow and return 0. */
+PNG_INTERNAL_FUNCTION(png_fixed_point,png_muldiv_warn,
+ (png_const_structrp png_ptr, png_fixed_point a, png_int_32 multiplied_by,
+ png_int_32 divided_by),PNG_EMPTY);
+#endif
+
+#ifdef PNG_GAMMA_SUPPORTED
+/* Calculate a reciprocal - used for gamma values. This returns
+ * 0 if the argument is 0 in order to maintain an undefined value;
+ * there are no warnings.
+ */
+PNG_INTERNAL_FUNCTION(png_fixed_point,png_reciprocal,(png_fixed_point a),
+ PNG_EMPTY);
+
+#ifdef PNG_READ_GAMMA_SUPPORTED
+/* The same but gives a reciprocal of the product of two fixed point
+ * values. Accuracy is suitable for gamma calculations but this is
+ * not exact - use png_muldiv for that. Only required at present on read.
+ */
+PNG_INTERNAL_FUNCTION(png_fixed_point,png_reciprocal2,(png_fixed_point a,
+ png_fixed_point b),PNG_EMPTY);
+#endif
+
+/* Return true if the gamma value is significantly different from 1.0 */
+PNG_INTERNAL_FUNCTION(int,png_gamma_significant,(png_fixed_point gamma_value),
+ PNG_EMPTY);
+#endif
+
+#ifdef PNG_READ_GAMMA_SUPPORTED
+/* Internal fixed point gamma correction. These APIs are called as
+ * required to convert single values - they don't need to be fast,
+ * they are not used when processing image pixel values.
+ *
+ * While the input is an 'unsigned' value it must actually be the
+ * correct bit value - 0..255 or 0..65535 as required.
+ */
+PNG_INTERNAL_FUNCTION(png_uint_16,png_gamma_correct,(png_structrp png_ptr,
+ unsigned int value, png_fixed_point gamma_value),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(png_uint_16,png_gamma_16bit_correct,(unsigned int value,
+ png_fixed_point gamma_value),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(png_byte,png_gamma_8bit_correct,(unsigned int value,
+ png_fixed_point gamma_value),PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_destroy_gamma_table,(png_structrp png_ptr),
+ PNG_EMPTY);
+PNG_INTERNAL_FUNCTION(void,png_build_gamma_table,(png_structrp png_ptr,
+ int bit_depth),PNG_EMPTY);
+#endif
+
+/* SIMPLIFIED READ/WRITE SUPPORT */
+#if defined(PNG_SIMPLIFIED_READ_SUPPORTED) ||\
+ defined(PNG_SIMPLIFIED_WRITE_SUPPORTED)
+/* The internal structure that png_image::opaque points to. */
+typedef struct png_control
+{
+ png_structp png_ptr;
+ png_infop info_ptr;
+ png_voidp error_buf; /* Always a jmp_buf at present. */
+
+ png_const_bytep memory; /* Memory buffer. */
+ png_size_t size; /* Size of the memory buffer. */
+
+ unsigned int for_write :1; /* Otherwise it is a read structure */
+ unsigned int owned_file :1; /* We own the file in io_ptr */
+} png_control;
+
+/* Return the pointer to the jmp_buf from a png_control: necessary because C
+ * does not reveal the type of the elements of jmp_buf.
+ */
+#ifdef __cplusplus
+# define png_control_jmp_buf(pc) (((jmp_buf*)((pc)->error_buf))[0])
+#else
+# define png_control_jmp_buf(pc) ((pc)->error_buf)
+#endif
+
+/* Utility to safely execute a piece of libpng code catching and logging any
+ * errors that might occur. Returns true on success, false on failure (either
+ * of the function or as a result of a png_error.)
+ */
+PNG_INTERNAL_CALLBACK(void,png_safe_error,(png_structp png_ptr,
+ png_const_charp error_message),PNG_NORETURN);
+
+#ifdef PNG_WARNINGS_SUPPORTED
+PNG_INTERNAL_CALLBACK(void,png_safe_warning,(png_structp png_ptr,
+ png_const_charp warning_message),PNG_EMPTY);
+#else
+# define png_safe_warning 0/*dummy argument*/
+#endif
+
+PNG_INTERNAL_FUNCTION(int,png_safe_execute,(png_imagep image,
+ int (*function)(png_voidp), png_voidp arg),PNG_EMPTY);
+
+/* Utility to log an error; this also cleans up the png_image; the function
+ * always returns 0 (false).
+ */
+PNG_INTERNAL_FUNCTION(int,png_image_error,(png_imagep image,
+ png_const_charp error_message),PNG_EMPTY);
+
+#ifndef PNG_SIMPLIFIED_READ_SUPPORTED
+/* png_image_free is used by the write code but not exported */
+PNG_INTERNAL_FUNCTION(void, png_image_free, (png_imagep image), PNG_EMPTY);
+#endif /* !SIMPLIFIED_READ */
+
+#endif /* SIMPLIFIED READ/WRITE */
+
+/* These are initialization functions for hardware specific PNG filter
+ * optimizations; list these here then select the appropriate one at compile
+ * time using the macro PNG_FILTER_OPTIMIZATIONS. If the macro is not defined
+ * the generic code is used.
+ */
+#ifdef PNG_FILTER_OPTIMIZATIONS
+PNG_INTERNAL_FUNCTION(void, PNG_FILTER_OPTIMIZATIONS, (png_structp png_ptr,
+ unsigned int bpp), PNG_EMPTY);
+ /* Just declare the optimization that will be used */
+#else
+ /* List *all* the possible optimizations here - this branch is required if
+ * the builder of libpng passes the definition of PNG_FILTER_OPTIMIZATIONS in
+ * CFLAGS in place of CPPFLAGS *and* uses symbol prefixing.
+ */
+PNG_INTERNAL_FUNCTION(void, png_init_filter_functions_neon,
+ (png_structp png_ptr, unsigned int bpp), PNG_EMPTY);
+#endif
+
+/* Maintainer: Put new private prototypes here ^ */
+
+#include "pngdebug.h"
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* PNG_VERSION_INFO_ONLY */
+#endif /* PNGPRIV_H */
--- /dev/null
+
+/* pngread.c - read a PNG file
+ *
+ * Last changed in libpng 1.6.17 [March 26, 2015]
+ * Copyright (c) 1998-2015 Glenn Randers-Pehrson
+ * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
+ * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ *
+ * This file contains routines that an application calls directly to
+ * read a PNG file or stream.
+ */
+
+#include "pngpriv.h"
+#if defined(PNG_SIMPLIFIED_READ_SUPPORTED) && defined(PNG_STDIO_SUPPORTED)
+# include <errno.h>
+#endif
+
+#ifdef PNG_READ_SUPPORTED
+
+/* Create a PNG structure for reading, and allocate any memory needed. */
+PNG_FUNCTION(png_structp,PNGAPI
+png_create_read_struct,(png_const_charp user_png_ver, png_voidp error_ptr,
+ png_error_ptr error_fn, png_error_ptr warn_fn),PNG_ALLOCATED)
+{
+#ifndef PNG_USER_MEM_SUPPORTED
+ png_structp png_ptr = png_create_png_struct(user_png_ver, error_ptr,
+ error_fn, warn_fn, NULL, NULL, NULL);
+#else
+ return png_create_read_struct_2(user_png_ver, error_ptr, error_fn,
+ warn_fn, NULL, NULL, NULL);
+}
+
+/* Alternate create PNG structure for reading, and allocate any memory
+ * needed.
+ */
+PNG_FUNCTION(png_structp,PNGAPI
+png_create_read_struct_2,(png_const_charp user_png_ver, png_voidp error_ptr,
+ png_error_ptr error_fn, png_error_ptr warn_fn, png_voidp mem_ptr,
+ png_malloc_ptr malloc_fn, png_free_ptr free_fn),PNG_ALLOCATED)
+{
+ png_structp png_ptr = png_create_png_struct(user_png_ver, error_ptr,
+ error_fn, warn_fn, mem_ptr, malloc_fn, free_fn);
+#endif /* USER_MEM */
+
+ if (png_ptr != NULL)
+ {
+ png_ptr->mode = PNG_IS_READ_STRUCT;
+
+ /* Added in libpng-1.6.0; this can be used to detect a read structure if
+ * required (it will be zero in a write structure.)
+ */
+# ifdef PNG_SEQUENTIAL_READ_SUPPORTED
+ png_ptr->IDAT_read_size = PNG_IDAT_READ_SIZE;
+# endif
+
+# ifdef PNG_BENIGN_READ_ERRORS_SUPPORTED
+ png_ptr->flags |= PNG_FLAG_BENIGN_ERRORS_WARN;
+
+ /* In stable builds only warn if an application error can be completely
+ * handled.
+ */
+# if PNG_LIBPNG_BUILD_BASE_TYPE >= PNG_LIBPNG_BUILD_RC
+ png_ptr->flags |= PNG_FLAG_APP_WARNINGS_WARN;
+# endif
+# endif
+
+ /* TODO: delay this, it can be done in png_init_io (if the app doesn't
+ * do it itself) avoiding setting the default function if it is not
+ * required.
+ */
+ png_set_read_fn(png_ptr, NULL, NULL);
+ }
+
+ return png_ptr;
+}
+
+
+#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
+/* Read the information before the actual image data. This has been
+ * changed in v0.90 to allow reading a file that already has the magic
+ * bytes read from the stream. You can tell libpng how many bytes have
+ * been read from the beginning of the stream (up to the maximum of 8)
+ * via png_set_sig_bytes(), and we will only check the remaining bytes
+ * here. The application can then have access to the signature bytes we
+ * read if it is determined that this isn't a valid PNG file.
+ */
+void PNGAPI
+png_read_info(png_structrp png_ptr, png_inforp info_ptr)
+{
+#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
+ int keep;
+#endif
+
+ png_debug(1, "in png_read_info");
+
+ if (png_ptr == NULL || info_ptr == NULL)
+ return;
+
+ /* Read and check the PNG file signature. */
+ png_read_sig(png_ptr, info_ptr);
+
+ for (;;)
+ {
+ png_uint_32 length = png_read_chunk_header(png_ptr);
+ png_uint_32 chunk_name = png_ptr->chunk_name;
+
+ /* IDAT logic needs to happen here to simplify getting the two flags
+ * right.
+ */
+ if (chunk_name == png_IDAT)
+ {
+ if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
+ png_chunk_error(png_ptr, "Missing IHDR before IDAT");
+
+ else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
+ (png_ptr->mode & PNG_HAVE_PLTE) == 0)
+ png_chunk_error(png_ptr, "Missing PLTE before IDAT");
+
+ else if ((png_ptr->mode & PNG_AFTER_IDAT) != 0)
+ png_chunk_benign_error(png_ptr, "Too many IDATs found");
+
+ png_ptr->mode |= PNG_HAVE_IDAT;
+ }
+
+ else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
+ png_ptr->mode |= PNG_AFTER_IDAT;
+
+ /* This should be a binary subdivision search or a hash for
+ * matching the chunk name rather than a linear search.
+ */
+ if (chunk_name == png_IHDR)
+ png_handle_IHDR(png_ptr, info_ptr, length);
+
+ else if (chunk_name == png_IEND)
+ png_handle_IEND(png_ptr, info_ptr, length);
+
+#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
+ else if ((keep = png_chunk_unknown_handling(png_ptr, chunk_name)) != 0)
+ {
+ png_handle_unknown(png_ptr, info_ptr, length, keep);
+
+ if (chunk_name == png_PLTE)
+ png_ptr->mode |= PNG_HAVE_PLTE;
+
+ else if (chunk_name == png_IDAT)
+ {
+ png_ptr->idat_size = 0; /* It has been consumed */
+ break;
+ }
+ }
+#endif
+ else if (chunk_name == png_PLTE)
+ png_handle_PLTE(png_ptr, info_ptr, length);
+
+ else if (chunk_name == png_IDAT)
+ {
+ png_ptr->idat_size = length;
+ break;
+ }
+
+#ifdef PNG_READ_bKGD_SUPPORTED
+ else if (chunk_name == png_bKGD)
+ png_handle_bKGD(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_cHRM_SUPPORTED
+ else if (chunk_name == png_cHRM)
+ png_handle_cHRM(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_gAMA_SUPPORTED
+ else if (chunk_name == png_gAMA)
+ png_handle_gAMA(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_hIST_SUPPORTED
+ else if (chunk_name == png_hIST)
+ png_handle_hIST(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_oFFs_SUPPORTED
+ else if (chunk_name == png_oFFs)
+ png_handle_oFFs(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_pCAL_SUPPORTED
+ else if (chunk_name == png_pCAL)
+ png_handle_pCAL(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_sCAL_SUPPORTED
+ else if (chunk_name == png_sCAL)
+ png_handle_sCAL(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_pHYs_SUPPORTED
+ else if (chunk_name == png_pHYs)
+ png_handle_pHYs(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_sBIT_SUPPORTED
+ else if (chunk_name == png_sBIT)
+ png_handle_sBIT(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_sRGB_SUPPORTED
+ else if (chunk_name == png_sRGB)
+ png_handle_sRGB(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_iCCP_SUPPORTED
+ else if (chunk_name == png_iCCP)
+ png_handle_iCCP(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_sPLT_SUPPORTED
+ else if (chunk_name == png_sPLT)
+ png_handle_sPLT(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_tEXt_SUPPORTED
+ else if (chunk_name == png_tEXt)
+ png_handle_tEXt(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_tIME_SUPPORTED
+ else if (chunk_name == png_tIME)
+ png_handle_tIME(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_tRNS_SUPPORTED
+ else if (chunk_name == png_tRNS)
+ png_handle_tRNS(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_zTXt_SUPPORTED
+ else if (chunk_name == png_zTXt)
+ png_handle_zTXt(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_iTXt_SUPPORTED
+ else if (chunk_name == png_iTXt)
+ png_handle_iTXt(png_ptr, info_ptr, length);
+#endif
+
+ else
+ png_handle_unknown(png_ptr, info_ptr, length,
+ PNG_HANDLE_CHUNK_AS_DEFAULT);
+ }
+}
+#endif /* SEQUENTIAL_READ */
+
+/* Optional call to update the users info_ptr structure */
+void PNGAPI
+png_read_update_info(png_structrp png_ptr, png_inforp info_ptr)
+{
+ png_debug(1, "in png_read_update_info");
+
+ if (png_ptr != NULL)
+ {
+ if ((png_ptr->flags & PNG_FLAG_ROW_INIT) == 0)
+ {
+ png_read_start_row(png_ptr);
+
+# ifdef PNG_READ_TRANSFORMS_SUPPORTED
+ png_read_transform_info(png_ptr, info_ptr);
+# else
+ PNG_UNUSED(info_ptr)
+# endif
+ }
+
+ /* New in 1.6.0 this avoids the bug of doing the initializations twice */
+ else
+ png_app_error(png_ptr,
+ "png_read_update_info/png_start_read_image: duplicate call");
+ }
+}
+
+#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
+/* Initialize palette, background, etc, after transformations
+ * are set, but before any reading takes place. This allows
+ * the user to obtain a gamma-corrected palette, for example.
+ * If the user doesn't call this, we will do it ourselves.
+ */
+void PNGAPI
+png_start_read_image(png_structrp png_ptr)
+{
+ png_debug(1, "in png_start_read_image");
+
+ if (png_ptr != NULL)
+ {
+ if ((png_ptr->flags & PNG_FLAG_ROW_INIT) == 0)
+ png_read_start_row(png_ptr);
+
+ /* New in 1.6.0 this avoids the bug of doing the initializations twice */
+ else
+ png_app_error(png_ptr,
+ "png_start_read_image/png_read_update_info: duplicate call");
+ }
+}
+#endif /* SEQUENTIAL_READ */
+
+#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
+#ifdef PNG_MNG_FEATURES_SUPPORTED
+/* Undoes intrapixel differencing,
+ * NOTE: this is apparently only supported in the 'sequential' reader.
+ */
+static void
+png_do_read_intrapixel(png_row_infop row_info, png_bytep row)
+{
+ png_debug(1, "in png_do_read_intrapixel");
+
+ if (
+ (row_info->color_type & PNG_COLOR_MASK_COLOR) != 0)
+ {
+ int bytes_per_pixel;
+ png_uint_32 row_width = row_info->width;
+
+ if (row_info->bit_depth == 8)
+ {
+ png_bytep rp;
+ png_uint_32 i;
+
+ if (row_info->color_type == PNG_COLOR_TYPE_RGB)
+ bytes_per_pixel = 3;
+
+ else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+ bytes_per_pixel = 4;
+
+ else
+ return;
+
+ for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel)
+ {
+ *(rp) = (png_byte)((256 + *rp + *(rp + 1)) & 0xff);
+ *(rp+2) = (png_byte)((256 + *(rp + 2) + *(rp + 1)) & 0xff);
+ }
+ }
+ else if (row_info->bit_depth == 16)
+ {
+ png_bytep rp;
+ png_uint_32 i;
+
+ if (row_info->color_type == PNG_COLOR_TYPE_RGB)
+ bytes_per_pixel = 6;
+
+ else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+ bytes_per_pixel = 8;
+
+ else
+ return;
+
+ for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel)
+ {
+ png_uint_32 s0 = (*(rp ) << 8) | *(rp + 1);
+ png_uint_32 s1 = (*(rp + 2) << 8) | *(rp + 3);
+ png_uint_32 s2 = (*(rp + 4) << 8) | *(rp + 5);
+ png_uint_32 red = (s0 + s1 + 65536) & 0xffff;
+ png_uint_32 blue = (s2 + s1 + 65536) & 0xffff;
+ *(rp ) = (png_byte)((red >> 8) & 0xff);
+ *(rp + 1) = (png_byte)(red & 0xff);
+ *(rp + 4) = (png_byte)((blue >> 8) & 0xff);
+ *(rp + 5) = (png_byte)(blue & 0xff);
+ }
+ }
+ }
+}
+#endif /* MNG_FEATURES */
+
+void PNGAPI
+png_read_row(png_structrp png_ptr, png_bytep row, png_bytep dsp_row)
+{
+ png_row_info row_info;
+
+ if (png_ptr == NULL)
+ return;
+
+ png_debug2(1, "in png_read_row (row %lu, pass %d)",
+ (unsigned long)png_ptr->row_number, png_ptr->pass);
+
+ /* png_read_start_row sets the information (in particular iwidth) for this
+ * interlace pass.
+ */
+ if ((png_ptr->flags & PNG_FLAG_ROW_INIT) == 0)
+ png_read_start_row(png_ptr);
+
+ /* 1.5.6: row_info moved out of png_struct to a local here. */
+ row_info.width = png_ptr->iwidth; /* NOTE: width of current interlaced row */
+ row_info.color_type = png_ptr->color_type;
+ row_info.bit_depth = png_ptr->bit_depth;
+ row_info.channels = png_ptr->channels;
+ row_info.pixel_depth = png_ptr->pixel_depth;
+ row_info.rowbytes = PNG_ROWBYTES(row_info.pixel_depth, row_info.width);
+
+#ifdef PNG_WARNINGS_SUPPORTED
+ if (png_ptr->row_number == 0 && png_ptr->pass == 0)
+ {
+ /* Check for transforms that have been set but were defined out */
+#if defined(PNG_WRITE_INVERT_SUPPORTED) && !defined(PNG_READ_INVERT_SUPPORTED)
+ if ((png_ptr->transformations & PNG_INVERT_MONO) != 0)
+ png_warning(png_ptr, "PNG_READ_INVERT_SUPPORTED is not defined");
+#endif
+
+#if defined(PNG_WRITE_FILLER_SUPPORTED) && !defined(PNG_READ_FILLER_SUPPORTED)
+ if ((png_ptr->transformations & PNG_FILLER) != 0)
+ png_warning(png_ptr, "PNG_READ_FILLER_SUPPORTED is not defined");
+#endif
+
+#if defined(PNG_WRITE_PACKSWAP_SUPPORTED) && \
+ !defined(PNG_READ_PACKSWAP_SUPPORTED)
+ if ((png_ptr->transformations & PNG_PACKSWAP) != 0)
+ png_warning(png_ptr, "PNG_READ_PACKSWAP_SUPPORTED is not defined");
+#endif
+
+#if defined(PNG_WRITE_PACK_SUPPORTED) && !defined(PNG_READ_PACK_SUPPORTED)
+ if ((png_ptr->transformations & PNG_PACK) != 0)
+ png_warning(png_ptr, "PNG_READ_PACK_SUPPORTED is not defined");
+#endif
+
+#if defined(PNG_WRITE_SHIFT_SUPPORTED) && !defined(PNG_READ_SHIFT_SUPPORTED)
+ if ((png_ptr->transformations & PNG_SHIFT) != 0)
+ png_warning(png_ptr, "PNG_READ_SHIFT_SUPPORTED is not defined");
+#endif
+
+#if defined(PNG_WRITE_BGR_SUPPORTED) && !defined(PNG_READ_BGR_SUPPORTED)
+ if ((png_ptr->transformations & PNG_BGR) != 0)
+ png_warning(png_ptr, "PNG_READ_BGR_SUPPORTED is not defined");
+#endif
+
+#if defined(PNG_WRITE_SWAP_SUPPORTED) && !defined(PNG_READ_SWAP_SUPPORTED)
+ if ((png_ptr->transformations & PNG_SWAP_BYTES) != 0)
+ png_warning(png_ptr, "PNG_READ_SWAP_SUPPORTED is not defined");
+#endif
+ }
+#endif /* WARNINGS */
+
+#ifdef PNG_READ_INTERLACING_SUPPORTED
+ /* If interlaced and we do not need a new row, combine row and return.
+ * Notice that the pixels we have from previous rows have been transformed
+ * already; we can only combine like with like (transformed or
+ * untransformed) and, because of the libpng API for interlaced images, this
+ * means we must transform before de-interlacing.
+ */
+ if (png_ptr->interlaced != 0 &&
+ (png_ptr->transformations & PNG_INTERLACE) != 0)
+ {
+ switch (png_ptr->pass)
+ {
+ case 0:
+ if (png_ptr->row_number & 0x07)
+ {
+ if (dsp_row != NULL)
+ png_combine_row(png_ptr, dsp_row, 1/*display*/);
+ png_read_finish_row(png_ptr);
+ return;
+ }
+ break;
+
+ case 1:
+ if ((png_ptr->row_number & 0x07) || png_ptr->width < 5)
+ {
+ if (dsp_row != NULL)
+ png_combine_row(png_ptr, dsp_row, 1/*display*/);
+
+ png_read_finish_row(png_ptr);
+ return;
+ }
+ break;
+
+ case 2:
+ if ((png_ptr->row_number & 0x07) != 4)
+ {
+ if (dsp_row != NULL && (png_ptr->row_number & 4))
+ png_combine_row(png_ptr, dsp_row, 1/*display*/);
+
+ png_read_finish_row(png_ptr);
+ return;
+ }
+ break;
+
+ case 3:
+ if ((png_ptr->row_number & 3) || png_ptr->width < 3)
+ {
+ if (dsp_row != NULL)
+ png_combine_row(png_ptr, dsp_row, 1/*display*/);
+
+ png_read_finish_row(png_ptr);
+ return;
+ }
+ break;
+
+ case 4:
+ if ((png_ptr->row_number & 3) != 2)
+ {
+ if (dsp_row != NULL && (png_ptr->row_number & 2))
+ png_combine_row(png_ptr, dsp_row, 1/*display*/);
+
+ png_read_finish_row(png_ptr);
+ return;
+ }
+ break;
+
+ case 5:
+ if ((png_ptr->row_number & 1) || png_ptr->width < 2)
+ {
+ if (dsp_row != NULL)
+ png_combine_row(png_ptr, dsp_row, 1/*display*/);
+
+ png_read_finish_row(png_ptr);
+ return;
+ }
+ break;
+
+ default:
+ case 6:
+ if ((png_ptr->row_number & 1) == 0)
+ {
+ png_read_finish_row(png_ptr);
+ return;
+ }
+ break;
+ }
+ }
+#endif
+
+ if ((png_ptr->mode & PNG_HAVE_IDAT) == 0)
+ png_error(png_ptr, "Invalid attempt to read row data");
+
+ /* Fill the row with IDAT data: */
+ png_read_IDAT_data(png_ptr, png_ptr->row_buf, row_info.rowbytes + 1);
+
+ if (png_ptr->row_buf[0] > PNG_FILTER_VALUE_NONE)
+ {
+ if (png_ptr->row_buf[0] < PNG_FILTER_VALUE_LAST)
+ png_read_filter_row(png_ptr, &row_info, png_ptr->row_buf + 1,
+ png_ptr->prev_row + 1, png_ptr->row_buf[0]);
+ else
+ png_error(png_ptr, "bad adaptive filter value");
+ }
+
+ /* libpng 1.5.6: the following line was copying png_ptr->rowbytes before
+ * 1.5.6, while the buffer really is this big in current versions of libpng
+ * it may not be in the future, so this was changed just to copy the
+ * interlaced count:
+ */
+ memcpy(png_ptr->prev_row, png_ptr->row_buf, row_info.rowbytes + 1);
+
+#ifdef PNG_MNG_FEATURES_SUPPORTED
+ if ((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) != 0 &&
+ (png_ptr->filter_type == PNG_INTRAPIXEL_DIFFERENCING))
+ {
+ /* Intrapixel differencing */
+ png_do_read_intrapixel(&row_info, png_ptr->row_buf + 1);
+ }
+#endif
+
+#ifdef PNG_READ_TRANSFORMS_SUPPORTED
+ if (png_ptr->transformations)
+ png_do_read_transformations(png_ptr, &row_info);
+#endif
+
+ /* The transformed pixel depth should match the depth now in row_info. */
+ if (png_ptr->transformed_pixel_depth == 0)
+ {
+ png_ptr->transformed_pixel_depth = row_info.pixel_depth;
+ if (row_info.pixel_depth > png_ptr->maximum_pixel_depth)
+ png_error(png_ptr, "sequential row overflow");
+ }
+
+ else if (png_ptr->transformed_pixel_depth != row_info.pixel_depth)
+ png_error(png_ptr, "internal sequential row size calculation error");
+
+#ifdef PNG_READ_INTERLACING_SUPPORTED
+ /* Expand interlaced rows to full size */
+ if (png_ptr->interlaced != 0 &&
+ (png_ptr->transformations & PNG_INTERLACE) != 0)
+ {
+ if (png_ptr->pass < 6)
+ png_do_read_interlace(&row_info, png_ptr->row_buf + 1, png_ptr->pass,
+ png_ptr->transformations);
+
+ if (dsp_row != NULL)
+ png_combine_row(png_ptr, dsp_row, 1/*display*/);
+
+ if (row != NULL)
+ png_combine_row(png_ptr, row, 0/*row*/);
+ }
+
+ else
+#endif
+ {
+ if (row != NULL)
+ png_combine_row(png_ptr, row, -1/*ignored*/);
+
+ if (dsp_row != NULL)
+ png_combine_row(png_ptr, dsp_row, -1/*ignored*/);
+ }
+ png_read_finish_row(png_ptr);
+
+ if (png_ptr->read_row_fn != NULL)
+ (*(png_ptr->read_row_fn))(png_ptr, png_ptr->row_number, png_ptr->pass);
+
+}
+#endif /* SEQUENTIAL_READ */
+
+#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
+/* Read one or more rows of image data. If the image is interlaced,
+ * and png_set_interlace_handling() has been called, the rows need to
+ * contain the contents of the rows from the previous pass. If the
+ * image has alpha or transparency, and png_handle_alpha()[*] has been
+ * called, the rows contents must be initialized to the contents of the
+ * screen.
+ *
+ * "row" holds the actual image, and pixels are placed in it
+ * as they arrive. If the image is displayed after each pass, it will
+ * appear to "sparkle" in. "display_row" can be used to display a
+ * "chunky" progressive image, with finer detail added as it becomes
+ * available. If you do not want this "chunky" display, you may pass
+ * NULL for display_row. If you do not want the sparkle display, and
+ * you have not called png_handle_alpha(), you may pass NULL for rows.
+ * If you have called png_handle_alpha(), and the image has either an
+ * alpha channel or a transparency chunk, you must provide a buffer for
+ * rows. In this case, you do not have to provide a display_row buffer
+ * also, but you may. If the image is not interlaced, or if you have
+ * not called png_set_interlace_handling(), the display_row buffer will
+ * be ignored, so pass NULL to it.
+ *
+ * [*] png_handle_alpha() does not exist yet, as of this version of libpng
+ */
+
+void PNGAPI
+png_read_rows(png_structrp png_ptr, png_bytepp row,
+ png_bytepp display_row, png_uint_32 num_rows)
+{
+ png_uint_32 i;
+ png_bytepp rp;
+ png_bytepp dp;
+
+ png_debug(1, "in png_read_rows");
+
+ if (png_ptr == NULL)
+ return;
+
+ rp = row;
+ dp = display_row;
+ if (rp != NULL && dp != NULL)
+ for (i = 0; i < num_rows; i++)
+ {
+ png_bytep rptr = *rp++;
+ png_bytep dptr = *dp++;
+
+ png_read_row(png_ptr, rptr, dptr);
+ }
+
+ else if (rp != NULL)
+ for (i = 0; i < num_rows; i++)
+ {
+ png_bytep rptr = *rp;
+ png_read_row(png_ptr, rptr, NULL);
+ rp++;
+ }
+
+ else if (dp != NULL)
+ for (i = 0; i < num_rows; i++)
+ {
+ png_bytep dptr = *dp;
+ png_read_row(png_ptr, NULL, dptr);
+ dp++;
+ }
+}
+#endif /* SEQUENTIAL_READ */
+
+#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
+/* Read the entire image. If the image has an alpha channel or a tRNS
+ * chunk, and you have called png_handle_alpha()[*], you will need to
+ * initialize the image to the current image that PNG will be overlaying.
+ * We set the num_rows again here, in case it was incorrectly set in
+ * png_read_start_row() by a call to png_read_update_info() or
+ * png_start_read_image() if png_set_interlace_handling() wasn't called
+ * prior to either of these functions like it should have been. You can
+ * only call this function once. If you desire to have an image for
+ * each pass of a interlaced image, use png_read_rows() instead.
+ *
+ * [*] png_handle_alpha() does not exist yet, as of this version of libpng
+ */
+void PNGAPI
+png_read_image(png_structrp png_ptr, png_bytepp image)
+{
+ png_uint_32 i, image_height;
+ int pass, j;
+ png_bytepp rp;
+
+ png_debug(1, "in png_read_image");
+
+ if (png_ptr == NULL)
+ return;
+
+#ifdef PNG_READ_INTERLACING_SUPPORTED
+ if ((png_ptr->flags & PNG_FLAG_ROW_INIT) == 0)
+ {
+ pass = png_set_interlace_handling(png_ptr);
+ /* And make sure transforms are initialized. */
+ png_start_read_image(png_ptr);
+ }
+ else
+ {
+ if (png_ptr->interlaced != 0 &&
+ (png_ptr->transformations & PNG_INTERLACE) == 0)
+ {
+ /* Caller called png_start_read_image or png_read_update_info without
+ * first turning on the PNG_INTERLACE transform. We can fix this here,
+ * but the caller should do it!
+ */
+ png_warning(png_ptr, "Interlace handling should be turned on when "
+ "using png_read_image");
+ /* Make sure this is set correctly */
+ png_ptr->num_rows = png_ptr->height;
+ }
+
+ /* Obtain the pass number, which also turns on the PNG_INTERLACE flag in
+ * the above error case.
+ */
+ pass = png_set_interlace_handling(png_ptr);
+ }
+#else
+ if (png_ptr->interlaced)
+ png_error(png_ptr,
+ "Cannot read interlaced image -- interlace handler disabled");
+
+ pass = 1;
+#endif
+
+ image_height=png_ptr->height;
+
+ for (j = 0; j < pass; j++)
+ {
+ rp = image;
+ for (i = 0; i < image_height; i++)
+ {
+ png_read_row(png_ptr, *rp, NULL);
+ rp++;
+ }
+ }
+}
+#endif /* SEQUENTIAL_READ */
+
+#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
+/* Read the end of the PNG file. Will not read past the end of the
+ * file, will verify the end is accurate, and will read any comments
+ * or time information at the end of the file, if info is not NULL.
+ */
+void PNGAPI
+png_read_end(png_structrp png_ptr, png_inforp info_ptr)
+{
+#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
+ int keep;
+#endif
+
+ png_debug(1, "in png_read_end");
+
+ if (png_ptr == NULL)
+ return;
+
+ /* If png_read_end is called in the middle of reading the rows there may
+ * still be pending IDAT data and an owned zstream. Deal with this here.
+ */
+#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
+ if (png_chunk_unknown_handling(png_ptr, png_IDAT) == 0)
+#endif
+ png_read_finish_IDAT(png_ptr);
+
+#ifdef PNG_READ_CHECK_FOR_INVALID_INDEX_SUPPORTED
+ /* Report invalid palette index; added at libng-1.5.10 */
+ if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
+ png_ptr->num_palette_max > png_ptr->num_palette)
+ png_benign_error(png_ptr, "Read palette index exceeding num_palette");
+#endif
+
+ do
+ {
+ png_uint_32 length = png_read_chunk_header(png_ptr);
+ png_uint_32 chunk_name = png_ptr->chunk_name;
+
+ if (chunk_name == png_IEND)
+ png_handle_IEND(png_ptr, info_ptr, length);
+
+ else if (chunk_name == png_IHDR)
+ png_handle_IHDR(png_ptr, info_ptr, length);
+
+ else if (info_ptr == NULL)
+ png_crc_finish(png_ptr, length);
+
+#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
+ else if ((keep = png_chunk_unknown_handling(png_ptr, chunk_name)) != 0)
+ {
+ if (chunk_name == png_IDAT)
+ {
+ if ((length > 0) ||
+ (png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT) != 0)
+ png_benign_error(png_ptr, "Too many IDATs found");
+ }
+ png_handle_unknown(png_ptr, info_ptr, length, keep);
+ if (chunk_name == png_PLTE)
+ png_ptr->mode |= PNG_HAVE_PLTE;
+ }
+#endif
+
+ else if (chunk_name == png_IDAT)
+ {
+ /* Zero length IDATs are legal after the last IDAT has been
+ * read, but not after other chunks have been read.
+ */
+ if ((length > 0) || (png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT) != 0)
+ png_benign_error(png_ptr, "Too many IDATs found");
+
+ png_crc_finish(png_ptr, length);
+ }
+ else if (chunk_name == png_PLTE)
+ png_handle_PLTE(png_ptr, info_ptr, length);
+
+#ifdef PNG_READ_bKGD_SUPPORTED
+ else if (chunk_name == png_bKGD)
+ png_handle_bKGD(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_cHRM_SUPPORTED
+ else if (chunk_name == png_cHRM)
+ png_handle_cHRM(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_gAMA_SUPPORTED
+ else if (chunk_name == png_gAMA)
+ png_handle_gAMA(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_hIST_SUPPORTED
+ else if (chunk_name == png_hIST)
+ png_handle_hIST(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_oFFs_SUPPORTED
+ else if (chunk_name == png_oFFs)
+ png_handle_oFFs(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_pCAL_SUPPORTED
+ else if (chunk_name == png_pCAL)
+ png_handle_pCAL(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_sCAL_SUPPORTED
+ else if (chunk_name == png_sCAL)
+ png_handle_sCAL(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_pHYs_SUPPORTED
+ else if (chunk_name == png_pHYs)
+ png_handle_pHYs(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_sBIT_SUPPORTED
+ else if (chunk_name == png_sBIT)
+ png_handle_sBIT(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_sRGB_SUPPORTED
+ else if (chunk_name == png_sRGB)
+ png_handle_sRGB(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_iCCP_SUPPORTED
+ else if (chunk_name == png_iCCP)
+ png_handle_iCCP(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_sPLT_SUPPORTED
+ else if (chunk_name == png_sPLT)
+ png_handle_sPLT(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_tEXt_SUPPORTED
+ else if (chunk_name == png_tEXt)
+ png_handle_tEXt(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_tIME_SUPPORTED
+ else if (chunk_name == png_tIME)
+ png_handle_tIME(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_tRNS_SUPPORTED
+ else if (chunk_name == png_tRNS)
+ png_handle_tRNS(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_zTXt_SUPPORTED
+ else if (chunk_name == png_zTXt)
+ png_handle_zTXt(png_ptr, info_ptr, length);
+#endif
+
+#ifdef PNG_READ_iTXt_SUPPORTED
+ else if (chunk_name == png_iTXt)
+ png_handle_iTXt(png_ptr, info_ptr, length);
+#endif
+
+ else
+ png_handle_unknown(png_ptr, info_ptr, length,
+ PNG_HANDLE_CHUNK_AS_DEFAULT);
+ } while ((png_ptr->mode & PNG_HAVE_IEND) == 0);
+}
+#endif /* SEQUENTIAL_READ */
+
+/* Free all memory used in the read struct */
+static void
+png_read_destroy(png_structrp png_ptr)
+{
+ png_debug(1, "in png_read_destroy");
+
+#ifdef PNG_READ_GAMMA_SUPPORTED
+ png_destroy_gamma_table(png_ptr);
+#endif
+
+ png_free(png_ptr, png_ptr->big_row_buf);
+ png_ptr->big_row_buf = NULL;
+ png_free(png_ptr, png_ptr->big_prev_row);
+ png_ptr->big_prev_row = NULL;
+ png_free(png_ptr, png_ptr->read_buffer);
+ png_ptr->read_buffer = NULL;
+
+#ifdef PNG_READ_QUANTIZE_SUPPORTED
+ png_free(png_ptr, png_ptr->palette_lookup);
+ png_ptr->palette_lookup = NULL;
+ png_free(png_ptr, png_ptr->quantize_index);
+ png_ptr->quantize_index = NULL;
+#endif
+
+ if ((png_ptr->free_me & PNG_FREE_PLTE) != 0)
+ {
+ png_zfree(png_ptr, png_ptr->palette);
+ png_ptr->palette = NULL;
+ }
+ png_ptr->free_me &= ~PNG_FREE_PLTE;
+
+#if defined(PNG_tRNS_SUPPORTED) || \
+ defined(PNG_READ_EXPAND_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
+ if ((png_ptr->free_me & PNG_FREE_TRNS) != 0)
+ {
+ png_free(png_ptr, png_ptr->trans_alpha);
+ png_ptr->trans_alpha = NULL;
+ }
+ png_ptr->free_me &= ~PNG_FREE_TRNS;
+#endif
+
+ inflateEnd(&png_ptr->zstream);
+
+#ifdef PNG_PROGRESSIVE_READ_SUPPORTED
+ png_free(png_ptr, png_ptr->save_buffer);
+ png_ptr->save_buffer = NULL;
+#endif
+
+#if defined(PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED) && \
+ defined(PNG_READ_UNKNOWN_CHUNKS_SUPPORTED)
+ png_free(png_ptr, png_ptr->unknown_chunk.data);
+ png_ptr->unknown_chunk.data = NULL;
+#endif
+
+#ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
+ png_free(png_ptr, png_ptr->chunk_list);
+ png_ptr->chunk_list = NULL;
+#endif
+
+ /* NOTE: the 'setjmp' buffer may still be allocated and the memory and error
+ * callbacks are still set at this point. They are required to complete the
+ * destruction of the png_struct itself.
+ */
+}
+
+/* Free all memory used by the read */
+void PNGAPI
+png_destroy_read_struct(png_structpp png_ptr_ptr, png_infopp info_ptr_ptr,
+ png_infopp end_info_ptr_ptr)
+{
+ png_structrp png_ptr = NULL;
+
+ png_debug(1, "in png_destroy_read_struct");
+
+ if (png_ptr_ptr != NULL)
+ png_ptr = *png_ptr_ptr;
+
+ if (png_ptr == NULL)
+ return;
+
+ /* libpng 1.6.0: use the API to destroy info structs to ensure consistent
+ * behavior. Prior to 1.6.0 libpng did extra 'info' destruction in this API.
+ * The extra was, apparently, unnecessary yet this hides memory leak bugs.
+ */
+ png_destroy_info_struct(png_ptr, end_info_ptr_ptr);
+ png_destroy_info_struct(png_ptr, info_ptr_ptr);
+
+ *png_ptr_ptr = NULL;
+ png_read_destroy(png_ptr);
+ png_destroy_png_struct(png_ptr);
+}
+
+void PNGAPI
+png_set_read_status_fn(png_structrp png_ptr, png_read_status_ptr read_row_fn)
+{
+ if (png_ptr == NULL)
+ return;
+
+ png_ptr->read_row_fn = read_row_fn;
+}
+
+
+#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
+#ifdef PNG_INFO_IMAGE_SUPPORTED
+void PNGAPI
+png_read_png(png_structrp png_ptr, png_inforp info_ptr,
+ int transforms,
+ voidp params)
+{
+ if (png_ptr == NULL || info_ptr == NULL)
+ return;
+
+ /* png_read_info() gives us all of the information from the
+ * PNG file before the first IDAT (image data chunk).
+ */
+ png_read_info(png_ptr, info_ptr);
+ if (info_ptr->height > PNG_UINT_32_MAX/(sizeof (png_bytep)))
+ png_error(png_ptr, "Image is too high to process with png_read_png()");
+
+ /* -------------- image transformations start here ------------------- */
+ /* libpng 1.6.10: add code to cause a png_app_error if a selected TRANSFORM
+ * is not implemented. This will only happen in de-configured (non-default)
+ * libpng builds. The results can be unexpected - png_read_png may return
+ * short or mal-formed rows because the transform is skipped.
+ */
+
+ /* Tell libpng to strip 16-bit/color files down to 8 bits per color.
+ */
+ if ((transforms & PNG_TRANSFORM_SCALE_16) != 0)
+ /* Added at libpng-1.5.4. "strip_16" produces the same result that it
+ * did in earlier versions, while "scale_16" is now more accurate.
+ */
+#ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
+ png_set_scale_16(png_ptr);
+#else
+ png_app_error(png_ptr, "PNG_TRANSFORM_SCALE_16 not supported");
+#endif
+
+ /* If both SCALE and STRIP are required pngrtran will effectively cancel the
+ * latter by doing SCALE first. This is ok and allows apps not to check for
+ * which is supported to get the right answer.
+ */
+ if ((transforms & PNG_TRANSFORM_STRIP_16) != 0)
+#ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
+ png_set_strip_16(png_ptr);
+#else
+ png_app_error(png_ptr, "PNG_TRANSFORM_STRIP_16 not supported");
+#endif
+
+ /* Strip alpha bytes from the input data without combining with
+ * the background (not recommended).
+ */
+ if ((transforms & PNG_TRANSFORM_STRIP_ALPHA) != 0)
+#ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
+ png_set_strip_alpha(png_ptr);
+#else
+ png_app_error(png_ptr, "PNG_TRANSFORM_STRIP_ALPHA not supported");
+#endif
+
+ /* Extract multiple pixels with bit depths of 1, 2, or 4 from a single
+ * byte into separate bytes (useful for paletted and grayscale images).
+ */
+ if ((transforms & PNG_TRANSFORM_PACKING) != 0)
+#ifdef PNG_READ_PACK_SUPPORTED
+ png_set_packing(png_ptr);
+#else
+ png_app_error(png_ptr, "PNG_TRANSFORM_PACKING not supported");
+#endif
+
+ /* Change the order of packed pixels to least significant bit first
+ * (not useful if you are using png_set_packing).
+ */
+ if ((transforms & PNG_TRANSFORM_PACKSWAP) != 0)
+#ifdef PNG_READ_PACKSWAP_SUPPORTED
+ png_set_packswap(png_ptr);
+#else
+ png_app_error(png_ptr, "PNG_TRANSFORM_PACKSWAP not supported");
+#endif
+
+ /* Expand paletted colors into true RGB triplets
+ * Expand grayscale images to full 8 bits from 1, 2, or 4 bits/pixel
+ * Expand paletted or RGB images with transparency to full alpha
+ * channels so the data will be available as RGBA quartets.
+ */
+ if ((transforms & PNG_TRANSFORM_EXPAND) != 0)
+#ifdef PNG_READ_EXPAND_SUPPORTED
+ png_set_expand(png_ptr);
+#else
+ png_app_error(png_ptr, "PNG_TRANSFORM_EXPAND not supported");
+#endif
+
+ /* We don't handle background color or gamma transformation or quantizing.
+ */
+
+ /* Invert monochrome files to have 0 as white and 1 as black
+ */
+ if ((transforms & PNG_TRANSFORM_INVERT_MONO) != 0)
+#ifdef PNG_READ_INVERT_SUPPORTED
+ png_set_invert_mono(png_ptr);
+#else
+ png_app_error(png_ptr, "PNG_TRANSFORM_INVERT_MONO not supported");
+#endif
+
+ /* If you want to shift the pixel values from the range [0,255] or
+ * [0,65535] to the original [0,7] or [0,31], or whatever range the
+ * colors were originally in:
+ */
+ if ((transforms & PNG_TRANSFORM_SHIFT) != 0)
+#ifdef PNG_READ_SHIFT_SUPPORTED
+ if ((info_ptr->valid & PNG_INFO_sBIT) != 0)
+ png_set_shift(png_ptr, &info_ptr->sig_bit);
+#else
+ png_app_error(png_ptr, "PNG_TRANSFORM_SHIFT not supported");
+#endif
+
+ /* Flip the RGB pixels to BGR (or RGBA to BGRA) */
+ if ((transforms & PNG_TRANSFORM_BGR) != 0)
+#ifdef PNG_READ_BGR_SUPPORTED
+ png_set_bgr(png_ptr);
+#else
+ png_app_error(png_ptr, "PNG_TRANSFORM_BGR not supported");
+#endif
+
+ /* Swap the RGBA or GA data to ARGB or AG (or BGRA to ABGR) */
+ if ((transforms & PNG_TRANSFORM_SWAP_ALPHA) != 0)
+#ifdef PNG_READ_SWAP_ALPHA_SUPPORTED
+ png_set_swap_alpha(png_ptr);
+#else
+ png_app_error(png_ptr, "PNG_TRANSFORM_SWAP_ALPHA not supported");
+#endif
+
+ /* Swap bytes of 16-bit files to least significant byte first */
+ if ((transforms & PNG_TRANSFORM_SWAP_ENDIAN) != 0)
+#ifdef PNG_READ_SWAP_SUPPORTED
+ png_set_swap(png_ptr);
+#else
+ png_app_error(png_ptr, "PNG_TRANSFORM_SWAP_ENDIAN not supported");
+#endif
+
+/* Added at libpng-1.2.41 */
+ /* Invert the alpha channel from opacity to transparency */
+ if ((transforms & PNG_TRANSFORM_INVERT_ALPHA) != 0)
+#ifdef PNG_READ_INVERT_ALPHA_SUPPORTED
+ png_set_invert_alpha(png_ptr);
+#else
+ png_app_error(png_ptr, "PNG_TRANSFORM_INVERT_ALPHA not supported");
+#endif
+
+/* Added at libpng-1.2.41 */
+ /* Expand grayscale image to RGB */
+ if ((transforms & PNG_TRANSFORM_GRAY_TO_RGB) != 0)
+#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
+ png_set_gray_to_rgb(png_ptr);
+#else
+ png_app_error(png_ptr, "PNG_TRANSFORM_GRAY_TO_RGB not supported");
+#endif
+
+/* Added at libpng-1.5.4 */
+ if ((transforms & PNG_TRANSFORM_EXPAND_16) != 0)
+#ifdef PNG_READ_EXPAND_16_SUPPORTED
+ png_set_expand_16(png_ptr);
+#else
+ png_app_error(png_ptr, "PNG_TRANSFORM_EXPAND_16 not supported");
+#endif
+
+ /* We don't handle adding filler bytes */
+
+ /* We use png_read_image and rely on that for interlace handling, but we also
+ * call png_read_update_info therefore must turn on interlace handling now:
+ */
+ (void)png_set_interlace_handling(png_ptr);
+
+ /* Optional call to gamma correct and add the background to the palette
+ * and update info structure. REQUIRED if you are expecting libpng to
+ * update the palette for you (i.e., you selected such a transform above).
+ */
+ png_read_update_info(png_ptr, info_ptr);
+
+ /* -------------- image transformations end here ------------------- */
+
+ png_free_data(png_ptr, info_ptr, PNG_FREE_ROWS, 0);
+ if (info_ptr->row_pointers == NULL)
+ {
+ png_uint_32 iptr;
+
+ info_ptr->row_pointers = png_voidcast(png_bytepp, png_malloc(png_ptr,
+ info_ptr->height * (sizeof (png_bytep))));
+
+ for (iptr=0; iptr<info_ptr->height; iptr++)
+ info_ptr->row_pointers[iptr] = NULL;
+
+ info_ptr->free_me |= PNG_FREE_ROWS;
+
+ for (iptr = 0; iptr < info_ptr->height; iptr++)
+ info_ptr->row_pointers[iptr] = png_voidcast(png_bytep,
+ png_malloc(png_ptr, info_ptr->rowbytes));
+ }
+
+ png_read_image(png_ptr, info_ptr->row_pointers);
+ info_ptr->valid |= PNG_INFO_IDAT;
+
+ /* Read rest of file, and get additional chunks in info_ptr - REQUIRED */
+ png_read_end(png_ptr, info_ptr);
+
+ PNG_UNUSED(params)
+}
+#endif /* INFO_IMAGE */
+#endif /* SEQUENTIAL_READ */
+
+#ifdef PNG_SIMPLIFIED_READ_SUPPORTED
+/* SIMPLIFIED READ
+ *
+ * This code currently relies on the sequential reader, though it could easily
+ * be made to work with the progressive one.
+ */
+/* Arguments to png_image_finish_read: */
+
+/* Encoding of PNG data (used by the color-map code) */
+# define P_NOTSET 0 /* File encoding not yet known */
+# define P_sRGB 1 /* 8-bit encoded to sRGB gamma */
+# define P_LINEAR 2 /* 16-bit linear: not encoded, NOT pre-multiplied! */
+# define P_FILE 3 /* 8-bit encoded to file gamma, not sRGB or linear */
+# define P_LINEAR8 4 /* 8-bit linear: only from a file value */
+
+/* Color-map processing: after libpng has run on the PNG image further
+ * processing may be needed to convert the data to color-map indices.
+ */
+#define PNG_CMAP_NONE 0
+#define PNG_CMAP_GA 1 /* Process GA data to a color-map with alpha */
+#define PNG_CMAP_TRANS 2 /* Process GA data to a background index */
+#define PNG_CMAP_RGB 3 /* Process RGB data */
+#define PNG_CMAP_RGB_ALPHA 4 /* Process RGBA data */
+
+/* The following document where the background is for each processing case. */
+#define PNG_CMAP_NONE_BACKGROUND 256
+#define PNG_CMAP_GA_BACKGROUND 231
+#define PNG_CMAP_TRANS_BACKGROUND 254
+#define PNG_CMAP_RGB_BACKGROUND 256
+#define PNG_CMAP_RGB_ALPHA_BACKGROUND 216
+
+typedef struct
+{
+ /* Arguments: */
+ png_imagep image;
+ png_voidp buffer;
+ png_int_32 row_stride;
+ png_voidp colormap;
+ png_const_colorp background;
+ /* Local variables: */
+ png_voidp local_row;
+ png_voidp first_row;
+ ptrdiff_t row_bytes; /* step between rows */
+ int file_encoding; /* E_ values above */
+ png_fixed_point gamma_to_linear; /* For P_FILE, reciprocal of gamma */
+ int colormap_processing; /* PNG_CMAP_ values above */
+} png_image_read_control;
+
+/* Do all the *safe* initialization - 'safe' means that png_error won't be
+ * called, so setting up the jmp_buf is not required. This means that anything
+ * called from here must *not* call png_malloc - it has to call png_malloc_warn
+ * instead so that control is returned safely back to this routine.
+ */
+static int
+png_image_read_init(png_imagep image)
+{
+ if (image->opaque == NULL)
+ {
+ png_structp png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, image,
+ png_safe_error, png_safe_warning);
+
+ /* And set the rest of the structure to NULL to ensure that the various
+ * fields are consistent.
+ */
+ memset(image, 0, (sizeof *image));
+ image->version = PNG_IMAGE_VERSION;
+
+ if (png_ptr != NULL)
+ {
+ png_infop info_ptr = png_create_info_struct(png_ptr);
+
+ if (info_ptr != NULL)
+ {
+ png_controlp control = png_voidcast(png_controlp,
+ png_malloc_warn(png_ptr, (sizeof *control)));
+
+ if (control != NULL)
+ {
+ memset(control, 0, (sizeof *control));
+
+ control->png_ptr = png_ptr;
+ control->info_ptr = info_ptr;
+ control->for_write = 0;
+
+ image->opaque = control;
+ return 1;
+ }
+
+ /* Error clean up */
+ png_destroy_info_struct(png_ptr, &info_ptr);
+ }
+
+ png_destroy_read_struct(&png_ptr, NULL, NULL);
+ }
+
+ return png_image_error(image, "png_image_read: out of memory");
+ }
+
+ return png_image_error(image, "png_image_read: opaque pointer not NULL");
+}
+
+/* Utility to find the base format of a PNG file from a png_struct. */
+static png_uint_32
+png_image_format(png_structrp png_ptr)
+{
+ png_uint_32 format = 0;
+
+ if ((png_ptr->color_type & PNG_COLOR_MASK_COLOR) != 0)
+ format |= PNG_FORMAT_FLAG_COLOR;
+
+ if ((png_ptr->color_type & PNG_COLOR_MASK_ALPHA) != 0)
+ format |= PNG_FORMAT_FLAG_ALPHA;
+
+ /* Use png_ptr here, not info_ptr, because by examination png_handle_tRNS
+ * sets the png_struct fields; that's all we are interested in here. The
+ * precise interaction with an app call to png_set_tRNS and PNG file reading
+ * is unclear.
+ */
+ else if (png_ptr->num_trans > 0)
+ format |= PNG_FORMAT_FLAG_ALPHA;
+
+ if (png_ptr->bit_depth == 16)
+ format |= PNG_FORMAT_FLAG_LINEAR;
+
+ if ((png_ptr->color_type & PNG_COLOR_MASK_PALETTE) != 0)
+ format |= PNG_FORMAT_FLAG_COLORMAP;
+
+ return format;
+}
+
+/* Is the given gamma significantly different from sRGB? The test is the same
+ * one used in pngrtran.c when deciding whether to do gamma correction. The
+ * arithmetic optimizes the division by using the fact that the inverse of the
+ * file sRGB gamma is 2.2
+ */
+static int
+png_gamma_not_sRGB(png_fixed_point g)
+{
+ if (g < PNG_FP_1)
+ {
+ /* An uninitialized gamma is assumed to be sRGB for the simplified API. */
+ if (g == 0)
+ return 0;
+
+ return png_gamma_significant((g * 11 + 2)/5 /* i.e. *2.2, rounded */);
+ }
+
+ return 1;
+}
+
+/* Do the main body of a 'png_image_begin_read' function; read the PNG file
+ * header and fill in all the information. This is executed in a safe context,
+ * unlike the init routine above.
+ */
+static int
+png_image_read_header(png_voidp argument)
+{
+ png_imagep image = png_voidcast(png_imagep, argument);
+ png_structrp png_ptr = image->opaque->png_ptr;
+ png_inforp info_ptr = image->opaque->info_ptr;
+
+ png_set_benign_errors(png_ptr, 1/*warn*/);
+ png_read_info(png_ptr, info_ptr);
+
+ /* Do this the fast way; just read directly out of png_struct. */
+ image->width = png_ptr->width;
+ image->height = png_ptr->height;
+
+ {
+ png_uint_32 format = png_image_format(png_ptr);
+
+ image->format = format;
+
+#ifdef PNG_COLORSPACE_SUPPORTED
+ /* Does the colorspace match sRGB? If there is no color endpoint
+ * (colorant) information assume yes, otherwise require the
+ * 'ENDPOINTS_MATCHP_sRGB' colorspace flag to have been set. If the
+ * colorspace has been determined to be invalid ignore it.
+ */
+ if ((format & PNG_FORMAT_FLAG_COLOR) != 0 && ((png_ptr->colorspace.flags
+ & (PNG_COLORSPACE_HAVE_ENDPOINTS|PNG_COLORSPACE_ENDPOINTS_MATCH_sRGB|
+ PNG_COLORSPACE_INVALID)) == PNG_COLORSPACE_HAVE_ENDPOINTS))
+ image->flags |= PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB;
+#endif
+ }
+
+ /* We need the maximum number of entries regardless of the format the
+ * application sets here.
+ */
+ {
+ png_uint_32 cmap_entries;
+
+ switch (png_ptr->color_type)
+ {
+ case PNG_COLOR_TYPE_GRAY:
+ cmap_entries = 1U << png_ptr->bit_depth;
+ break;
+
+ case PNG_COLOR_TYPE_PALETTE:
+ cmap_entries = png_ptr->num_palette;
+ break;
+
+ default:
+ cmap_entries = 256;
+ break;
+ }
+
+ if (cmap_entries > 256)
+ cmap_entries = 256;
+
+ image->colormap_entries = cmap_entries;
+ }
+
+ return 1;
+}
+
+#ifdef PNG_STDIO_SUPPORTED
+int PNGAPI
+png_image_begin_read_from_stdio(png_imagep image, FILE* file)
+{
+ if (image != NULL && image->version == PNG_IMAGE_VERSION)
+ {
+ if (file != NULL)
+ {
+ if (png_image_read_init(image) != 0)
+ {
+ /* This is slightly evil, but png_init_io doesn't do anything other
+ * than this and we haven't changed the standard IO functions so
+ * this saves a 'safe' function.
+ */
+ image->opaque->png_ptr->io_ptr = file;
+ return png_safe_execute(image, png_image_read_header, image);
+ }
+ }
+
+ else
+ return png_image_error(image,
+ "png_image_begin_read_from_stdio: invalid argument");
+ }
+
+ else if (image != NULL)
+ return png_image_error(image,
+ "png_image_begin_read_from_stdio: incorrect PNG_IMAGE_VERSION");
+
+ return 0;
+}
+
+int PNGAPI
+png_image_begin_read_from_file(png_imagep image, const char *file_name)
+{
+ if (image != NULL && image->version == PNG_IMAGE_VERSION)
+ {
+ if (file_name != NULL)
+ {
+ FILE *fp = fopen(file_name, "rb");
+
+ if (fp != NULL)
+ {
+ if (png_image_read_init(image) != 0)
+ {
+ image->opaque->png_ptr->io_ptr = fp;
+ image->opaque->owned_file = 1;
+ return png_safe_execute(image, png_image_read_header, image);
+ }
+
+ /* Clean up: just the opened file. */
+ (void)fclose(fp);
+ }
+
+ else
+ return png_image_error(image, strerror(errno));
+ }
+
+ else
+ return png_image_error(image,
+ "png_image_begin_read_from_file: invalid argument");
+ }
+
+ else if (image != NULL)
+ return png_image_error(image,
+ "png_image_begin_read_from_file: incorrect PNG_IMAGE_VERSION");
+
+ return 0;
+}
+#endif /* STDIO */
+
+static void PNGCBAPI
+png_image_memory_read(png_structp png_ptr, png_bytep out, png_size_t need)
+{
+ if (png_ptr != NULL)
+ {
+ png_imagep image = png_voidcast(png_imagep, png_ptr->io_ptr);
+ if (image != NULL)
+ {
+ png_controlp cp = image->opaque;
+ if (cp != NULL)
+ {
+ png_const_bytep memory = cp->memory;
+ png_size_t size = cp->size;
+
+ if (memory != NULL && size >= need)
+ {
+ memcpy(out, memory, need);
+ cp->memory = memory + need;
+ cp->size = size - need;
+ return;
+ }
+
+ png_error(png_ptr, "read beyond end of data");
+ }
+ }
+
+ png_error(png_ptr, "invalid memory read");
+ }
+}
+
+int PNGAPI png_image_begin_read_from_memory(png_imagep image,
+ png_const_voidp memory, png_size_t size)
+{
+ if (image != NULL && image->version == PNG_IMAGE_VERSION)
+ {
+ if (memory != NULL && size > 0)
+ {
+ if (png_image_read_init(image) != 0)
+ {
+ /* Now set the IO functions to read from the memory buffer and
+ * store it into io_ptr. Again do this in-place to avoid calling a
+ * libpng function that requires error handling.
+ */
+ image->opaque->memory = png_voidcast(png_const_bytep, memory);
+ image->opaque->size = size;
+ image->opaque->png_ptr->io_ptr = image;
+ image->opaque->png_ptr->read_data_fn = png_image_memory_read;
+
+ return png_safe_execute(image, png_image_read_header, image);
+ }
+ }
+
+ else
+ return png_image_error(image,
+ "png_image_begin_read_from_memory: invalid argument");
+ }
+
+ else if (image != NULL)
+ return png_image_error(image,
+ "png_image_begin_read_from_memory: incorrect PNG_IMAGE_VERSION");
+
+ return 0;
+}
+
+/* Utility function to skip chunks that are not used by the simplified image
+ * read functions and an appropriate macro to call it.
+ */
+#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
+static void
+png_image_skip_unused_chunks(png_structrp png_ptr)
+{
+ /* Prepare the reader to ignore all recognized chunks whose data will not
+ * be used, i.e., all chunks recognized by libpng except for those
+ * involved in basic image reading:
+ *
+ * IHDR, PLTE, IDAT, IEND
+ *
+ * Or image data handling:
+ *
+ * tRNS, bKGD, gAMA, cHRM, sRGB, [iCCP] and sBIT.
+ *
+ * This provides a small performance improvement and eliminates any
+ * potential vulnerability to security problems in the unused chunks.
+ *
+ * At present the iCCP chunk data isn't used, so iCCP chunk can be ignored
+ * too. This allows the simplified API to be compiled without iCCP support,
+ * however if the support is there the chunk is still checked to detect
+ * errors (which are unfortunately quite common.)
+ */
+ {
+ static PNG_CONST png_byte chunks_to_process[] = {
+ 98, 75, 71, 68, '\0', /* bKGD */
+ 99, 72, 82, 77, '\0', /* cHRM */
+ 103, 65, 77, 65, '\0', /* gAMA */
+# ifdef PNG_READ_iCCP_SUPPORTED
+ 105, 67, 67, 80, '\0', /* iCCP */
+# endif
+ 115, 66, 73, 84, '\0', /* sBIT */
+ 115, 82, 71, 66, '\0', /* sRGB */
+ };
+
+ /* Ignore unknown chunks and all other chunks except for the
+ * IHDR, PLTE, tRNS, IDAT, and IEND chunks.
+ */
+ png_set_keep_unknown_chunks(png_ptr, PNG_HANDLE_CHUNK_NEVER,
+ NULL, -1);
+
+ /* But do not ignore image data handling chunks */
+ png_set_keep_unknown_chunks(png_ptr, PNG_HANDLE_CHUNK_AS_DEFAULT,
+ chunks_to_process, (int)/*SAFE*/(sizeof chunks_to_process)/5);
+ }
+}
+
+# define PNG_SKIP_CHUNKS(p) png_image_skip_unused_chunks(p)
+#else
+# define PNG_SKIP_CHUNKS(p) ((void)0)
+#endif /* HANDLE_AS_UNKNOWN */
+
+/* The following macro gives the exact rounded answer for all values in the
+ * range 0..255 (it actually divides by 51.2, but the rounding still generates
+ * the correct numbers 0..5
+ */
+#define PNG_DIV51(v8) (((v8) * 5 + 130) >> 8)
+
+/* Utility functions to make particular color-maps */
+static void
+set_file_encoding(png_image_read_control *display)
+{
+ png_fixed_point g = display->image->opaque->png_ptr->colorspace.gamma;
+ if (png_gamma_significant(g) != 0)
+ {
+ if (png_gamma_not_sRGB(g) != 0)
+ {
+ display->file_encoding = P_FILE;
+ display->gamma_to_linear = png_reciprocal(g);
+ }
+
+ else
+ display->file_encoding = P_sRGB;
+ }
+
+ else
+ display->file_encoding = P_LINEAR8;
+}
+
+static unsigned int
+decode_gamma(png_image_read_control *display, png_uint_32 value, int encoding)
+{
+ if (encoding == P_FILE) /* double check */
+ encoding = display->file_encoding;
+
+ if (encoding == P_NOTSET) /* must be the file encoding */
+ {
+ set_file_encoding(display);
+ encoding = display->file_encoding;
+ }
+
+ switch (encoding)
+ {
+ case P_FILE:
+ value = png_gamma_16bit_correct(value*257, display->gamma_to_linear);
+ break;
+
+ case P_sRGB:
+ value = png_sRGB_table[value];
+ break;
+
+ case P_LINEAR:
+ break;
+
+ case P_LINEAR8:
+ value *= 257;
+ break;
+
+ default:
+ png_error(display->image->opaque->png_ptr,
+ "unexpected encoding (internal error)");
+ break;
+ }
+
+ return value;
+}
+
+static png_uint_32
+png_colormap_compose(png_image_read_control *display,
+ png_uint_32 foreground, int foreground_encoding, png_uint_32 alpha,
+ png_uint_32 background, int encoding)
+{
+ /* The file value is composed on the background, the background has the given
+ * encoding and so does the result, the file is encoded with P_FILE and the
+ * file and alpha are 8-bit values. The (output) encoding will always be
+ * P_LINEAR or P_sRGB.
+ */
+ png_uint_32 f = decode_gamma(display, foreground, foreground_encoding);
+ png_uint_32 b = decode_gamma(display, background, encoding);
+
+ /* The alpha is always an 8-bit value (it comes from the palette), the value
+ * scaled by 255 is what PNG_sRGB_FROM_LINEAR requires.
+ */
+ f = f * alpha + b * (255-alpha);
+
+ if (encoding == P_LINEAR)
+ {
+ /* Scale to 65535; divide by 255, approximately (in fact this is extremely
+ * accurate, it divides by 255.00000005937181414556, with no overflow.)
+ */
+ f *= 257; /* Now scaled by 65535 */
+ f += f >> 16;
+ f = (f+32768) >> 16;
+ }
+
+ else /* P_sRGB */
+ f = PNG_sRGB_FROM_LINEAR(f);
+
+ return f;
+}
+
+/* NOTE: P_LINEAR values to this routine must be 16-bit, but P_FILE values must
+ * be 8-bit.
+ */
+static void
+png_create_colormap_entry(png_image_read_control *display,
+ png_uint_32 ip, png_uint_32 red, png_uint_32 green, png_uint_32 blue,
+ png_uint_32 alpha, int encoding)
+{
+ png_imagep image = display->image;
+ const int output_encoding = (image->format & PNG_FORMAT_FLAG_LINEAR) != 0 ?
+ P_LINEAR : P_sRGB;
+ const int convert_to_Y = (image->format & PNG_FORMAT_FLAG_COLOR) == 0 &&
+ (red != green || green != blue);
+
+ if (ip > 255)
+ png_error(image->opaque->png_ptr, "color-map index out of range");
+
+ /* Update the cache with whether the file gamma is significantly different
+ * from sRGB.
+ */
+ if (encoding == P_FILE)
+ {
+ if (display->file_encoding == P_NOTSET)
+ set_file_encoding(display);
+
+ /* Note that the cached value may be P_FILE too, but if it is then the
+ * gamma_to_linear member has been set.
+ */
+ encoding = display->file_encoding;
+ }
+
+ if (encoding == P_FILE)
+ {
+ png_fixed_point g = display->gamma_to_linear;
+
+ red = png_gamma_16bit_correct(red*257, g);
+ green = png_gamma_16bit_correct(green*257, g);
+ blue = png_gamma_16bit_correct(blue*257, g);
+
+ if (convert_to_Y != 0 || output_encoding == P_LINEAR)
+ {
+ alpha *= 257;
+ encoding = P_LINEAR;
+ }
+
+ else
+ {
+ red = PNG_sRGB_FROM_LINEAR(red * 255);
+ green = PNG_sRGB_FROM_LINEAR(green * 255);
+ blue = PNG_sRGB_FROM_LINEAR(blue * 255);
+ encoding = P_sRGB;
+ }
+ }
+
+ else if (encoding == P_LINEAR8)
+ {
+ /* This encoding occurs quite frequently in test cases because PngSuite
+ * includes a gAMA 1.0 chunk with most images.
+ */
+ red *= 257;
+ green *= 257;
+ blue *= 257;
+ alpha *= 257;
+ encoding = P_LINEAR;
+ }
+
+ else if (encoding == P_sRGB &&
+ (convert_to_Y != 0 || output_encoding == P_LINEAR))
+ {
+ /* The values are 8-bit sRGB values, but must be converted to 16-bit
+ * linear.
+ */
+ red = png_sRGB_table[red];
+ green = png_sRGB_table[green];
+ blue = png_sRGB_table[blue];
+ alpha *= 257;
+ encoding = P_LINEAR;
+ }
+
+ /* This is set if the color isn't gray but the output is. */
+ if (encoding == P_LINEAR)
+ {
+ if (convert_to_Y != 0)
+ {
+ /* NOTE: these values are copied from png_do_rgb_to_gray */
+ png_uint_32 y = (png_uint_32)6968 * red + (png_uint_32)23434 * green +
+ (png_uint_32)2366 * blue;
+
+ if (output_encoding == P_LINEAR)
+ y = (y + 16384) >> 15;
+
+ else
+ {
+ /* y is scaled by 32768, we need it scaled by 255: */
+ y = (y + 128) >> 8;
+ y *= 255;
+ y = PNG_sRGB_FROM_LINEAR((y + 64) >> 7);
+ alpha = PNG_DIV257(alpha);
+ encoding = P_sRGB;
+ }
+
+ blue = red = green = y;
+ }
+
+ else if (output_encoding == P_sRGB)
+ {
+ red = PNG_sRGB_FROM_LINEAR(red * 255);
+ green = PNG_sRGB_FROM_LINEAR(green * 255);
+ blue = PNG_sRGB_FROM_LINEAR(blue * 255);
+ alpha = PNG_DIV257(alpha);
+ encoding = P_sRGB;
+ }
+ }
+
+ if (encoding != output_encoding)
+ png_error(image->opaque->png_ptr, "bad encoding (internal error)");
+
+ /* Store the value. */
+ {
+# ifdef PNG_FORMAT_AFIRST_SUPPORTED
+ const int afirst = (image->format & PNG_FORMAT_FLAG_AFIRST) != 0 &&
+ (image->format & PNG_FORMAT_FLAG_ALPHA) != 0;
+# else
+# define afirst 0
+# endif
+# ifdef PNG_FORMAT_BGR_SUPPORTED
+ const int bgr = (image->format & PNG_FORMAT_FLAG_BGR) != 0 ? 2 : 0;
+# else
+# define bgr 0
+# endif
+
+ if (output_encoding == P_LINEAR)
+ {
+ png_uint_16p entry = png_voidcast(png_uint_16p, display->colormap);
+
+ entry += ip * PNG_IMAGE_SAMPLE_CHANNELS(image->format);
+
+ /* The linear 16-bit values must be pre-multiplied by the alpha channel
+ * value, if less than 65535 (this is, effectively, composite on black
+ * if the alpha channel is removed.)
+ */
+ switch (PNG_IMAGE_SAMPLE_CHANNELS(image->format))
+ {
+ case 4:
+ entry[afirst ? 0 : 3] = (png_uint_16)alpha;
+ /* FALL THROUGH */
+
+ case 3:
+ if (alpha < 65535)
+ {
+ if (alpha > 0)
+ {
+ blue = (blue * alpha + 32767U)/65535U;
+ green = (green * alpha + 32767U)/65535U;
+ red = (red * alpha + 32767U)/65535U;
+ }
+
+ else
+ red = green = blue = 0;
+ }
+ entry[afirst + (2 ^ bgr)] = (png_uint_16)blue;
+ entry[afirst + 1] = (png_uint_16)green;
+ entry[afirst + bgr] = (png_uint_16)red;
+ break;
+
+ case 2:
+ entry[1 ^ afirst] = (png_uint_16)alpha;
+ /* FALL THROUGH */
+
+ case 1:
+ if (alpha < 65535)
+ {
+ if (alpha > 0)
+ green = (green * alpha + 32767U)/65535U;
+
+ else
+ green = 0;
+ }
+ entry[afirst] = (png_uint_16)green;
+ break;
+
+ default:
+ break;
+ }
+ }
+
+ else /* output encoding is P_sRGB */
+ {
+ png_bytep entry = png_voidcast(png_bytep, display->colormap);
+
+ entry += ip * PNG_IMAGE_SAMPLE_CHANNELS(image->format);
+
+ switch (PNG_IMAGE_SAMPLE_CHANNELS(image->format))
+ {
+ case 4:
+ entry[afirst ? 0 : 3] = (png_byte)alpha;
+ case 3:
+ entry[afirst + (2 ^ bgr)] = (png_byte)blue;
+ entry[afirst + 1] = (png_byte)green;
+ entry[afirst + bgr] = (png_byte)red;
+ break;
+
+ case 2:
+ entry[1 ^ afirst] = (png_byte)alpha;
+ case 1:
+ entry[afirst] = (png_byte)green;
+ break;
+
+ default:
+ break;
+ }
+ }
+
+# ifdef afirst
+# undef afirst
+# endif
+# ifdef bgr
+# undef bgr
+# endif
+ }
+}
+
+static int
+make_gray_file_colormap(png_image_read_control *display)
+{
+ unsigned int i;
+
+ for (i=0; i<256; ++i)
+ png_create_colormap_entry(display, i, i, i, i, 255, P_FILE);
+
+ return i;
+}
+
+static int
+make_gray_colormap(png_image_read_control *display)
+{
+ unsigned int i;
+
+ for (i=0; i<256; ++i)
+ png_create_colormap_entry(display, i, i, i, i, 255, P_sRGB);
+
+ return i;
+}
+#define PNG_GRAY_COLORMAP_ENTRIES 256
+
+static int
+make_ga_colormap(png_image_read_control *display)
+{
+ unsigned int i, a;
+
+ /* Alpha is retained, the output will be a color-map with entries
+ * selected by six levels of alpha. One transparent entry, 6 gray
+ * levels for all the intermediate alpha values, leaving 230 entries
+ * for the opaque grays. The color-map entries are the six values
+ * [0..5]*51, the GA processing uses PNG_DIV51(value) to find the
+ * relevant entry.
+ *
+ * if (alpha > 229) // opaque
+ * {
+ * // The 231 entries are selected to make the math below work:
+ * base = 0;
+ * entry = (231 * gray + 128) >> 8;
+ * }
+ * else if (alpha < 26) // transparent
+ * {
+ * base = 231;
+ * entry = 0;
+ * }
+ * else // partially opaque
+ * {
+ * base = 226 + 6 * PNG_DIV51(alpha);
+ * entry = PNG_DIV51(gray);
+ * }
+ */
+ i = 0;
+ while (i < 231)
+ {
+ unsigned int gray = (i * 256 + 115) / 231;
+ png_create_colormap_entry(display, i++, gray, gray, gray, 255, P_sRGB);
+ }
+
+ /* 255 is used here for the component values for consistency with the code
+ * that undoes premultiplication in pngwrite.c.
+ */
+ png_create_colormap_entry(display, i++, 255, 255, 255, 0, P_sRGB);
+
+ for (a=1; a<5; ++a)
+ {
+ unsigned int g;
+
+ for (g=0; g<6; ++g)
+ png_create_colormap_entry(display, i++, g*51, g*51, g*51, a*51,
+ P_sRGB);
+ }
+
+ return i;
+}
+
+#define PNG_GA_COLORMAP_ENTRIES 256
+
+static int
+make_rgb_colormap(png_image_read_control *display)
+{
+ unsigned int i, r;
+
+ /* Build a 6x6x6 opaque RGB cube */
+ for (i=r=0; r<6; ++r)
+ {
+ unsigned int g;
+
+ for (g=0; g<6; ++g)
+ {
+ unsigned int b;
+
+ for (b=0; b<6; ++b)
+ png_create_colormap_entry(display, i++, r*51, g*51, b*51, 255,
+ P_sRGB);
+ }
+ }
+
+ return i;
+}
+
+#define PNG_RGB_COLORMAP_ENTRIES 216
+
+/* Return a palette index to the above palette given three 8-bit sRGB values. */
+#define PNG_RGB_INDEX(r,g,b) \
+ ((png_byte)(6 * (6 * PNG_DIV51(r) + PNG_DIV51(g)) + PNG_DIV51(b)))
+
+static int
+png_image_read_colormap(png_voidp argument)
+{
+ png_image_read_control *display =
+ png_voidcast(png_image_read_control*, argument);
+ const png_imagep image = display->image;
+
+ const png_structrp png_ptr = image->opaque->png_ptr;
+ const png_uint_32 output_format = image->format;
+ const int output_encoding = (output_format & PNG_FORMAT_FLAG_LINEAR) != 0 ?
+ P_LINEAR : P_sRGB;
+
+ unsigned int cmap_entries;
+ unsigned int output_processing; /* Output processing option */
+ unsigned int data_encoding = P_NOTSET; /* Encoding libpng must produce */
+
+ /* Background information; the background color and the index of this color
+ * in the color-map if it exists (else 256).
+ */
+ unsigned int background_index = 256;
+ png_uint_32 back_r, back_g, back_b;
+
+ /* Flags to accumulate things that need to be done to the input. */
+ int expand_tRNS = 0;
+
+ /* Exclude the NYI feature of compositing onto a color-mapped buffer; it is
+ * very difficult to do, the results look awful, and it is difficult to see
+ * what possible use it is because the application can't control the
+ * color-map.
+ */
+ if (((png_ptr->color_type & PNG_COLOR_MASK_ALPHA) != 0 ||
+ png_ptr->num_trans > 0) /* alpha in input */ &&
+ ((output_format & PNG_FORMAT_FLAG_ALPHA) == 0) /* no alpha in output */)
+ {
+ if (output_encoding == P_LINEAR) /* compose on black */
+ back_b = back_g = back_r = 0;
+
+ else if (display->background == NULL /* no way to remove it */)
+ png_error(png_ptr,
+ "a background color must be supplied to remove alpha/transparency");
+
+ /* Get a copy of the background color (this avoids repeating the checks
+ * below.) The encoding is 8-bit sRGB or 16-bit linear, depending on the
+ * output format.
+ */
+ else
+ {
+ back_g = display->background->green;
+ if ((output_format & PNG_FORMAT_FLAG_COLOR) != 0)
+ {
+ back_r = display->background->red;
+ back_b = display->background->blue;
+ }
+ else
+ back_b = back_r = back_g;
+ }
+ }
+
+ else if (output_encoding == P_LINEAR)
+ back_b = back_r = back_g = 65535;
+
+ else
+ back_b = back_r = back_g = 255;
+
+ /* Default the input file gamma if required - this is necessary because
+ * libpng assumes that if no gamma information is present the data is in the
+ * output format, but the simplified API deduces the gamma from the input
+ * format.
+ */
+ if ((png_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_GAMMA) == 0)
+ {
+ /* Do this directly, not using the png_colorspace functions, to ensure
+ * that it happens even if the colorspace is invalid (though probably if
+ * it is the setting will be ignored) Note that the same thing can be
+ * achieved at the application interface with png_set_gAMA.
+ */
+ if (png_ptr->bit_depth == 16 &&
+ (image->flags & PNG_IMAGE_FLAG_16BIT_sRGB) == 0)
+ png_ptr->colorspace.gamma = PNG_GAMMA_LINEAR;
+
+ else
+ png_ptr->colorspace.gamma = PNG_GAMMA_sRGB_INVERSE;
+
+ png_ptr->colorspace.flags |= PNG_COLORSPACE_HAVE_GAMMA;
+ }
+
+ /* Decide what to do based on the PNG color type of the input data. The
+ * utility function png_create_colormap_entry deals with most aspects of the
+ * output transformations; this code works out how to produce bytes of
+ * color-map entries from the original format.
+ */
+ switch (png_ptr->color_type)
+ {
+ case PNG_COLOR_TYPE_GRAY:
+ if (png_ptr->bit_depth <= 8)
+ {
+ /* There at most 256 colors in the output, regardless of
+ * transparency.
+ */
+ unsigned int step, i, val, trans = 256/*ignore*/, back_alpha = 0;
+
+ cmap_entries = 1U << png_ptr->bit_depth;
+ if (cmap_entries > image->colormap_entries)
+ png_error(png_ptr, "gray[8] color-map: too few entries");
+
+ step = 255 / (cmap_entries - 1);
+ output_processing = PNG_CMAP_NONE;
+
+ /* If there is a tRNS chunk then this either selects a transparent
+ * value or, if the output has no alpha, the background color.
+ */
+ if (png_ptr->num_trans > 0)
+ {
+ trans = png_ptr->trans_color.gray;
+
+ if ((output_format & PNG_FORMAT_FLAG_ALPHA) == 0)
+ back_alpha = output_encoding == P_LINEAR ? 65535 : 255;
+ }
+
+ /* png_create_colormap_entry just takes an RGBA and writes the
+ * corresponding color-map entry using the format from 'image',
+ * including the required conversion to sRGB or linear as
+ * appropriate. The input values are always either sRGB (if the
+ * gamma correction flag is 0) or 0..255 scaled file encoded values
+ * (if the function must gamma correct them).
+ */
+ for (i=val=0; i<cmap_entries; ++i, val += step)
+ {
+ /* 'i' is a file value. While this will result in duplicated
+ * entries for 8-bit non-sRGB encoded files it is necessary to
+ * have non-gamma corrected values to do tRNS handling.
+ */
+ if (i != trans)
+ png_create_colormap_entry(display, i, val, val, val, 255,
+ P_FILE/*8-bit with file gamma*/);
+
+ /* Else this entry is transparent. The colors don't matter if
+ * there is an alpha channel (back_alpha == 0), but it does no
+ * harm to pass them in; the values are not set above so this
+ * passes in white.
+ *
+ * NOTE: this preserves the full precision of the application
+ * supplied background color when it is used.
+ */
+ else
+ png_create_colormap_entry(display, i, back_r, back_g, back_b,
+ back_alpha, output_encoding);
+ }
+
+ /* We need libpng to preserve the original encoding. */
+ data_encoding = P_FILE;
+
+ /* The rows from libpng, while technically gray values, are now also
+ * color-map indices; however, they may need to be expanded to 1
+ * byte per pixel. This is what png_set_packing does (i.e., it
+ * unpacks the bit values into bytes.)
+ */
+ if (png_ptr->bit_depth < 8)
+ png_set_packing(png_ptr);
+ }
+
+ else /* bit depth is 16 */
+ {
+ /* The 16-bit input values can be converted directly to 8-bit gamma
+ * encoded values; however, if a tRNS chunk is present 257 color-map
+ * entries are required. This means that the extra entry requires
+ * special processing; add an alpha channel, sacrifice gray level
+ * 254 and convert transparent (alpha==0) entries to that.
+ *
+ * Use libpng to chop the data to 8 bits. Convert it to sRGB at the
+ * same time to minimize quality loss. If a tRNS chunk is present
+ * this means libpng must handle it too; otherwise it is impossible
+ * to do the exact match on the 16-bit value.
+ *
+ * If the output has no alpha channel *and* the background color is
+ * gray then it is possible to let libpng handle the substitution by
+ * ensuring that the corresponding gray level matches the background
+ * color exactly.
+ */
+ data_encoding = P_sRGB;
+
+ if (PNG_GRAY_COLORMAP_ENTRIES > image->colormap_entries)
+ png_error(png_ptr, "gray[16] color-map: too few entries");
+
+ cmap_entries = make_gray_colormap(display);
+
+ if (png_ptr->num_trans > 0)
+ {
+ unsigned int back_alpha;
+
+ if ((output_format & PNG_FORMAT_FLAG_ALPHA) != 0)
+ back_alpha = 0;
+
+ else
+ {
+ if (back_r == back_g && back_g == back_b)
+ {
+ /* Background is gray; no special processing will be
+ * required.
+ */
+ png_color_16 c;
+ png_uint_32 gray = back_g;
+
+ if (output_encoding == P_LINEAR)
+ {
+ gray = PNG_sRGB_FROM_LINEAR(gray * 255);
+
+ /* And make sure the corresponding palette entry
+ * matches.
+ */
+ png_create_colormap_entry(display, gray, back_g, back_g,
+ back_g, 65535, P_LINEAR);
+ }
+
+ /* The background passed to libpng, however, must be the
+ * sRGB value.
+ */
+ c.index = 0; /*unused*/
+ c.gray = c.red = c.green = c.blue = (png_uint_16)gray;
+
+ /* NOTE: does this work without expanding tRNS to alpha?
+ * It should be the color->gray case below apparently
+ * doesn't.
+ */
+ png_set_background_fixed(png_ptr, &c,
+ PNG_BACKGROUND_GAMMA_SCREEN, 0/*need_expand*/,
+ 0/*gamma: not used*/);
+
+ output_processing = PNG_CMAP_NONE;
+ break;
+ }
+#ifdef __COVERITY__
+ /* Coverity claims that output_encoding cannot be 2 (P_LINEAR)
+ * here.
+ */
+ back_alpha = 255;
+#else
+ back_alpha = output_encoding == P_LINEAR ? 65535 : 255;
+#endif
+ }
+
+ /* output_processing means that the libpng-processed row will be
+ * 8-bit GA and it has to be processing to single byte color-map
+ * values. Entry 254 is replaced by either a completely
+ * transparent entry or by the background color at full
+ * precision (and the background color is not a simple gray
+ * level in this case.)
+ */
+ expand_tRNS = 1;
+ output_processing = PNG_CMAP_TRANS;
+ background_index = 254;
+
+ /* And set (overwrite) color-map entry 254 to the actual
+ * background color at full precision.
+ */
+ png_create_colormap_entry(display, 254, back_r, back_g, back_b,
+ back_alpha, output_encoding);
+ }
+
+ else
+ output_processing = PNG_CMAP_NONE;
+ }
+ break;
+
+ case PNG_COLOR_TYPE_GRAY_ALPHA:
+ /* 8-bit or 16-bit PNG with two channels - gray and alpha. A minimum
+ * of 65536 combinations. If, however, the alpha channel is to be
+ * removed there are only 256 possibilities if the background is gray.
+ * (Otherwise there is a subset of the 65536 possibilities defined by
+ * the triangle between black, white and the background color.)
+ *
+ * Reduce 16-bit files to 8-bit and sRGB encode the result. No need to
+ * worry about tRNS matching - tRNS is ignored if there is an alpha
+ * channel.
+ */
+ data_encoding = P_sRGB;
+
+ if ((output_format & PNG_FORMAT_FLAG_ALPHA) != 0)
+ {
+ if (PNG_GA_COLORMAP_ENTRIES > image->colormap_entries)
+ png_error(png_ptr, "gray+alpha color-map: too few entries");
+
+ cmap_entries = make_ga_colormap(display);
+
+ background_index = PNG_CMAP_GA_BACKGROUND;
+ output_processing = PNG_CMAP_GA;
+ }
+
+ else /* alpha is removed */
+ {
+ /* Alpha must be removed as the PNG data is processed when the
+ * background is a color because the G and A channels are
+ * independent and the vector addition (non-parallel vectors) is a
+ * 2-D problem.
+ *
+ * This can be reduced to the same algorithm as above by making a
+ * colormap containing gray levels (for the opaque grays), a
+ * background entry (for a transparent pixel) and a set of four six
+ * level color values, one set for each intermediate alpha value.
+ * See the comments in make_ga_colormap for how this works in the
+ * per-pixel processing.
+ *
+ * If the background is gray, however, we only need a 256 entry gray
+ * level color map. It is sufficient to make the entry generated
+ * for the background color be exactly the color specified.
+ */
+ if ((output_format & PNG_FORMAT_FLAG_COLOR) == 0 ||
+ (back_r == back_g && back_g == back_b))
+ {
+ /* Background is gray; no special processing will be required. */
+ png_color_16 c;
+ png_uint_32 gray = back_g;
+
+ if (PNG_GRAY_COLORMAP_ENTRIES > image->colormap_entries)
+ png_error(png_ptr, "gray-alpha color-map: too few entries");
+
+ cmap_entries = make_gray_colormap(display);
+
+ if (output_encoding == P_LINEAR)
+ {
+ gray = PNG_sRGB_FROM_LINEAR(gray * 255);
+
+ /* And make sure the corresponding palette entry matches. */
+ png_create_colormap_entry(display, gray, back_g, back_g,
+ back_g, 65535, P_LINEAR);
+ }
+
+ /* The background passed to libpng, however, must be the sRGB
+ * value.
+ */
+ c.index = 0; /*unused*/
+ c.gray = c.red = c.green = c.blue = (png_uint_16)gray;
+
+ png_set_background_fixed(png_ptr, &c,
+ PNG_BACKGROUND_GAMMA_SCREEN, 0/*need_expand*/,
+ 0/*gamma: not used*/);
+
+ output_processing = PNG_CMAP_NONE;
+ }
+
+ else
+ {
+ png_uint_32 i, a;
+
+ /* This is the same as png_make_ga_colormap, above, except that
+ * the entries are all opaque.
+ */
+ if (PNG_GA_COLORMAP_ENTRIES > image->colormap_entries)
+ png_error(png_ptr, "ga-alpha color-map: too few entries");
+
+ i = 0;
+ while (i < 231)
+ {
+ png_uint_32 gray = (i * 256 + 115) / 231;
+ png_create_colormap_entry(display, i++, gray, gray, gray,
+ 255, P_sRGB);
+ }
+
+ /* NOTE: this preserves the full precision of the application
+ * background color.
+ */
+ background_index = i;
+ png_create_colormap_entry(display, i++, back_r, back_g, back_b,
+#ifdef __COVERITY__
+ /* Coverity claims that output_encoding cannot be 2 (P_LINEAR)
+ * here.
+ */ 255U,
+#else
+ output_encoding == P_LINEAR ? 65535U : 255U,
+#endif
+ output_encoding);
+
+ /* For non-opaque input composite on the sRGB background - this
+ * requires inverting the encoding for each component. The input
+ * is still converted to the sRGB encoding because this is a
+ * reasonable approximate to the logarithmic curve of human
+ * visual sensitivity, at least over the narrow range which PNG
+ * represents. Consequently 'G' is always sRGB encoded, while
+ * 'A' is linear. We need the linear background colors.
+ */
+ if (output_encoding == P_sRGB) /* else already linear */
+ {
+ /* This may produce a value not exactly matching the
+ * background, but that's ok because these numbers are only
+ * used when alpha != 0
+ */
+ back_r = png_sRGB_table[back_r];
+ back_g = png_sRGB_table[back_g];
+ back_b = png_sRGB_table[back_b];
+ }
+
+ for (a=1; a<5; ++a)
+ {
+ unsigned int g;
+
+ /* PNG_sRGB_FROM_LINEAR expects a 16-bit linear value scaled
+ * by an 8-bit alpha value (0..255).
+ */
+ png_uint_32 alpha = 51 * a;
+ png_uint_32 back_rx = (255-alpha) * back_r;
+ png_uint_32 back_gx = (255-alpha) * back_g;
+ png_uint_32 back_bx = (255-alpha) * back_b;
+
+ for (g=0; g<6; ++g)
+ {
+ png_uint_32 gray = png_sRGB_table[g*51] * alpha;
+
+ png_create_colormap_entry(display, i++,
+ PNG_sRGB_FROM_LINEAR(gray + back_rx),
+ PNG_sRGB_FROM_LINEAR(gray + back_gx),
+ PNG_sRGB_FROM_LINEAR(gray + back_bx), 255, P_sRGB);
+ }
+ }
+
+ cmap_entries = i;
+ output_processing = PNG_CMAP_GA;
+ }
+ }
+ break;
+
+ case PNG_COLOR_TYPE_RGB:
+ case PNG_COLOR_TYPE_RGB_ALPHA:
+ /* Exclude the case where the output is gray; we can always handle this
+ * with the cases above.
+ */
+ if ((output_format & PNG_FORMAT_FLAG_COLOR) == 0)
+ {
+ /* The color-map will be grayscale, so we may as well convert the
+ * input RGB values to a simple grayscale and use the grayscale
+ * code above.
+ *
+ * NOTE: calling this apparently damages the recognition of the
+ * transparent color in background color handling; call
+ * png_set_tRNS_to_alpha before png_set_background_fixed.
+ */
+ png_set_rgb_to_gray_fixed(png_ptr, PNG_ERROR_ACTION_NONE, -1,
+ -1);
+ data_encoding = P_sRGB;
+
+ /* The output will now be one or two 8-bit gray or gray+alpha
+ * channels. The more complex case arises when the input has alpha.
+ */
+ if ((png_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA ||
+ png_ptr->num_trans > 0) &&
+ (output_format & PNG_FORMAT_FLAG_ALPHA) != 0)
+ {
+ /* Both input and output have an alpha channel, so no background
+ * processing is required; just map the GA bytes to the right
+ * color-map entry.
+ */
+ expand_tRNS = 1;
+
+ if (PNG_GA_COLORMAP_ENTRIES > image->colormap_entries)
+ png_error(png_ptr, "rgb[ga] color-map: too few entries");
+
+ cmap_entries = make_ga_colormap(display);
+ background_index = PNG_CMAP_GA_BACKGROUND;
+ output_processing = PNG_CMAP_GA;
+ }
+
+ else
+ {
+ /* Either the input or the output has no alpha channel, so there
+ * will be no non-opaque pixels in the color-map; it will just be
+ * grayscale.
+ */
+ if (PNG_GRAY_COLORMAP_ENTRIES > image->colormap_entries)
+ png_error(png_ptr, "rgb[gray] color-map: too few entries");
+
+ /* Ideally this code would use libpng to do the gamma correction,
+ * but if an input alpha channel is to be removed we will hit the
+ * libpng bug in gamma+compose+rgb-to-gray (the double gamma
+ * correction bug). Fix this by dropping the gamma correction in
+ * this case and doing it in the palette; this will result in
+ * duplicate palette entries, but that's better than the
+ * alternative of double gamma correction.
+ */
+ if ((png_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA ||
+ png_ptr->num_trans > 0) &&
+ png_gamma_not_sRGB(png_ptr->colorspace.gamma) != 0)
+ {
+ cmap_entries = make_gray_file_colormap(display);
+ data_encoding = P_FILE;
+ }
+
+ else
+ cmap_entries = make_gray_colormap(display);
+
+ /* But if the input has alpha or transparency it must be removed
+ */
+ if (png_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA ||
+ png_ptr->num_trans > 0)
+ {
+ png_color_16 c;
+ png_uint_32 gray = back_g;
+
+ /* We need to ensure that the application background exists in
+ * the colormap and that completely transparent pixels map to
+ * it. Achieve this simply by ensuring that the entry
+ * selected for the background really is the background color.
+ */
+ if (data_encoding == P_FILE) /* from the fixup above */
+ {
+ /* The app supplied a gray which is in output_encoding, we
+ * need to convert it to a value of the input (P_FILE)
+ * encoding then set this palette entry to the required
+ * output encoding.
+ */
+ if (output_encoding == P_sRGB)
+ gray = png_sRGB_table[gray]; /* now P_LINEAR */
+
+ gray = PNG_DIV257(png_gamma_16bit_correct(gray,
+ png_ptr->colorspace.gamma)); /* now P_FILE */
+
+ /* And make sure the corresponding palette entry contains
+ * exactly the required sRGB value.
+ */
+ png_create_colormap_entry(display, gray, back_g, back_g,
+ back_g, 0/*unused*/, output_encoding);
+ }
+
+ else if (output_encoding == P_LINEAR)
+ {
+ gray = PNG_sRGB_FROM_LINEAR(gray * 255);
+
+ /* And make sure the corresponding palette entry matches.
+ */
+ png_create_colormap_entry(display, gray, back_g, back_g,
+ back_g, 0/*unused*/, P_LINEAR);
+ }
+
+ /* The background passed to libpng, however, must be the
+ * output (normally sRGB) value.
+ */
+ c.index = 0; /*unused*/
+ c.gray = c.red = c.green = c.blue = (png_uint_16)gray;
+
+ /* NOTE: the following is apparently a bug in libpng. Without
+ * it the transparent color recognition in
+ * png_set_background_fixed seems to go wrong.
+ */
+ expand_tRNS = 1;
+ png_set_background_fixed(png_ptr, &c,
+ PNG_BACKGROUND_GAMMA_SCREEN, 0/*need_expand*/,
+ 0/*gamma: not used*/);
+ }
+
+ output_processing = PNG_CMAP_NONE;
+ }
+ }
+
+ else /* output is color */
+ {
+ /* We could use png_quantize here so long as there is no transparent
+ * color or alpha; png_quantize ignores alpha. Easier overall just
+ * to do it once and using PNG_DIV51 on the 6x6x6 reduced RGB cube.
+ * Consequently we always want libpng to produce sRGB data.
+ */
+ data_encoding = P_sRGB;
+
+ /* Is there any transparency or alpha? */
+ if (png_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA ||
+ png_ptr->num_trans > 0)
+ {
+ /* Is there alpha in the output too? If so all four channels are
+ * processed into a special RGB cube with alpha support.
+ */
+ if ((output_format & PNG_FORMAT_FLAG_ALPHA) != 0)
+ {
+ png_uint_32 r;
+
+ if (PNG_RGB_COLORMAP_ENTRIES+1+27 > image->colormap_entries)
+ png_error(png_ptr, "rgb+alpha color-map: too few entries");
+
+ cmap_entries = make_rgb_colormap(display);
+
+ /* Add a transparent entry. */
+ png_create_colormap_entry(display, cmap_entries, 255, 255,
+ 255, 0, P_sRGB);
+
+ /* This is stored as the background index for the processing
+ * algorithm.
+ */
+ background_index = cmap_entries++;
+
+ /* Add 27 r,g,b entries each with alpha 0.5. */
+ for (r=0; r<256; r = (r << 1) | 0x7f)
+ {
+ png_uint_32 g;
+
+ for (g=0; g<256; g = (g << 1) | 0x7f)
+ {
+ png_uint_32 b;
+
+ /* This generates components with the values 0, 127 and
+ * 255
+ */
+ for (b=0; b<256; b = (b << 1) | 0x7f)
+ png_create_colormap_entry(display, cmap_entries++,
+ r, g, b, 128, P_sRGB);
+ }
+ }
+
+ expand_tRNS = 1;
+ output_processing = PNG_CMAP_RGB_ALPHA;
+ }
+
+ else
+ {
+ /* Alpha/transparency must be removed. The background must
+ * exist in the color map (achieved by setting adding it after
+ * the 666 color-map). If the standard processing code will
+ * pick up this entry automatically that's all that is
+ * required; libpng can be called to do the background
+ * processing.
+ */
+ unsigned int sample_size =
+ PNG_IMAGE_SAMPLE_SIZE(output_format);
+ png_uint_32 r, g, b; /* sRGB background */
+
+ if (PNG_RGB_COLORMAP_ENTRIES+1+27 > image->colormap_entries)
+ png_error(png_ptr, "rgb-alpha color-map: too few entries");
+
+ cmap_entries = make_rgb_colormap(display);
+
+ png_create_colormap_entry(display, cmap_entries, back_r,
+ back_g, back_b, 0/*unused*/, output_encoding);
+
+ if (output_encoding == P_LINEAR)
+ {
+ r = PNG_sRGB_FROM_LINEAR(back_r * 255);
+ g = PNG_sRGB_FROM_LINEAR(back_g * 255);
+ b = PNG_sRGB_FROM_LINEAR(back_b * 255);
+ }
+
+ else
+ {
+ r = back_r;
+ g = back_g;
+ b = back_g;
+ }
+
+ /* Compare the newly-created color-map entry with the one the
+ * PNG_CMAP_RGB algorithm will use. If the two entries don't
+ * match, add the new one and set this as the background
+ * index.
+ */
+ if (memcmp((png_const_bytep)display->colormap +
+ sample_size * cmap_entries,
+ (png_const_bytep)display->colormap +
+ sample_size * PNG_RGB_INDEX(r,g,b),
+ sample_size) != 0)
+ {
+ /* The background color must be added. */
+ background_index = cmap_entries++;
+
+ /* Add 27 r,g,b entries each with created by composing with
+ * the background at alpha 0.5.
+ */
+ for (r=0; r<256; r = (r << 1) | 0x7f)
+ {
+ for (g=0; g<256; g = (g << 1) | 0x7f)
+ {
+ /* This generates components with the values 0, 127
+ * and 255
+ */
+ for (b=0; b<256; b = (b << 1) | 0x7f)
+ png_create_colormap_entry(display, cmap_entries++,
+ png_colormap_compose(display, r, P_sRGB, 128,
+ back_r, output_encoding),
+ png_colormap_compose(display, g, P_sRGB, 128,
+ back_g, output_encoding),
+ png_colormap_compose(display, b, P_sRGB, 128,
+ back_b, output_encoding),
+ 0/*unused*/, output_encoding);
+ }
+ }
+
+ expand_tRNS = 1;
+ output_processing = PNG_CMAP_RGB_ALPHA;
+ }
+
+ else /* background color is in the standard color-map */
+ {
+ png_color_16 c;
+
+ c.index = 0; /*unused*/
+ c.red = (png_uint_16)back_r;
+ c.gray = c.green = (png_uint_16)back_g;
+ c.blue = (png_uint_16)back_b;
+
+ png_set_background_fixed(png_ptr, &c,
+ PNG_BACKGROUND_GAMMA_SCREEN, 0/*need_expand*/,
+ 0/*gamma: not used*/);
+
+ output_processing = PNG_CMAP_RGB;
+ }
+ }
+ }
+
+ else /* no alpha or transparency in the input */
+ {
+ /* Alpha in the output is irrelevant, simply map the opaque input
+ * pixels to the 6x6x6 color-map.
+ */
+ if (PNG_RGB_COLORMAP_ENTRIES > image->colormap_entries)
+ png_error(png_ptr, "rgb color-map: too few entries");
+
+ cmap_entries = make_rgb_colormap(display);
+ output_processing = PNG_CMAP_RGB;
+ }
+ }
+ break;
+
+ case PNG_COLOR_TYPE_PALETTE:
+ /* It's already got a color-map. It may be necessary to eliminate the
+ * tRNS entries though.
+ */
+ {
+ unsigned int num_trans = png_ptr->num_trans;
+ png_const_bytep trans = num_trans > 0 ? png_ptr->trans_alpha : NULL;
+ png_const_colorp colormap = png_ptr->palette;
+ const int do_background = trans != NULL &&
+ (output_format & PNG_FORMAT_FLAG_ALPHA) == 0;
+ unsigned int i;
+
+ /* Just in case: */
+ if (trans == NULL)
+ num_trans = 0;
+
+ output_processing = PNG_CMAP_NONE;
+ data_encoding = P_FILE; /* Don't change from color-map indices */
+ cmap_entries = png_ptr->num_palette;
+ if (cmap_entries > 256)
+ cmap_entries = 256;
+
+ if (cmap_entries > image->colormap_entries)
+ png_error(png_ptr, "palette color-map: too few entries");
+
+ for (i=0; i < cmap_entries; ++i)
+ {
+ if (do_background != 0 && i < num_trans && trans[i] < 255)
+ {
+ if (trans[i] == 0)
+ png_create_colormap_entry(display, i, back_r, back_g,
+ back_b, 0, output_encoding);
+
+ else
+ {
+ /* Must compose the PNG file color in the color-map entry
+ * on the sRGB color in 'back'.
+ */
+ png_create_colormap_entry(display, i,
+ png_colormap_compose(display, colormap[i].red, P_FILE,
+ trans[i], back_r, output_encoding),
+ png_colormap_compose(display, colormap[i].green, P_FILE,
+ trans[i], back_g, output_encoding),
+ png_colormap_compose(display, colormap[i].blue, P_FILE,
+ trans[i], back_b, output_encoding),
+ output_encoding == P_LINEAR ? trans[i] * 257U :
+ trans[i],
+ output_encoding);
+ }
+ }
+
+ else
+ png_create_colormap_entry(display, i, colormap[i].red,
+ colormap[i].green, colormap[i].blue,
+ i < num_trans ? trans[i] : 255U, P_FILE/*8-bit*/);
+ }
+
+ /* The PNG data may have indices packed in fewer than 8 bits, it
+ * must be expanded if so.
+ */
+ if (png_ptr->bit_depth < 8)
+ png_set_packing(png_ptr);
+ }
+ break;
+
+ default:
+ png_error(png_ptr, "invalid PNG color type");
+ /*NOT REACHED*/
+ break;
+ }
+
+ /* Now deal with the output processing */
+ if (expand_tRNS != 0 && png_ptr->num_trans > 0 &&
+ (png_ptr->color_type & PNG_COLOR_MASK_ALPHA) == 0)
+ png_set_tRNS_to_alpha(png_ptr);
+
+ switch (data_encoding)
+ {
+ default:
+ png_error(png_ptr, "bad data option (internal error)");
+ break;
+
+ case P_sRGB:
+ /* Change to 8-bit sRGB */
+ png_set_alpha_mode_fixed(png_ptr, PNG_ALPHA_PNG, PNG_GAMMA_sRGB);
+ /* FALL THROUGH */
+
+ case P_FILE:
+ if (png_ptr->bit_depth > 8)
+ png_set_scale_16(png_ptr);
+ break;
+ }
+
+ if (cmap_entries > 256 || cmap_entries > image->colormap_entries)
+ png_error(png_ptr, "color map overflow (BAD internal error)");
+
+ image->colormap_entries = cmap_entries;
+
+ /* Double check using the recorded background index */
+ switch (output_processing)
+ {
+ case PNG_CMAP_NONE:
+ if (background_index != PNG_CMAP_NONE_BACKGROUND)
+ goto bad_background;
+ break;
+
+ case PNG_CMAP_GA:
+ if (background_index != PNG_CMAP_GA_BACKGROUND)
+ goto bad_background;
+ break;
+
+ case PNG_CMAP_TRANS:
+ if (background_index >= cmap_entries ||
+ background_index != PNG_CMAP_TRANS_BACKGROUND)
+ goto bad_background;
+ break;
+
+ case PNG_CMAP_RGB:
+ if (background_index != PNG_CMAP_RGB_BACKGROUND)
+ goto bad_background;
+ break;
+
+ case PNG_CMAP_RGB_ALPHA:
+ if (background_index != PNG_CMAP_RGB_ALPHA_BACKGROUND)
+ goto bad_background;
+ break;
+
+ default:
+ png_error(png_ptr, "bad processing option (internal error)");
+
+ bad_background:
+ png_error(png_ptr, "bad background index (internal error)");
+ }
+
+ display->colormap_processing = output_processing;
+
+ return 1/*ok*/;
+}
+
+/* The final part of the color-map read called from png_image_finish_read. */
+static int
+png_image_read_and_map(png_voidp argument)
+{
+ png_image_read_control *display = png_voidcast(png_image_read_control*,
+ argument);
+ png_imagep image = display->image;
+ png_structrp png_ptr = image->opaque->png_ptr;
+ int passes;
+
+ /* Called when the libpng data must be transformed into the color-mapped
+ * form. There is a local row buffer in display->local and this routine must
+ * do the interlace handling.
+ */
+ switch (png_ptr->interlaced)
+ {
+ case PNG_INTERLACE_NONE:
+ passes = 1;
+ break;
+
+ case PNG_INTERLACE_ADAM7:
+ passes = PNG_INTERLACE_ADAM7_PASSES;
+ break;
+
+ default:
+ png_error(png_ptr, "unknown interlace type");
+ }
+
+ {
+ png_uint_32 height = image->height;
+ png_uint_32 width = image->width;
+ int proc = display->colormap_processing;
+ png_bytep first_row = png_voidcast(png_bytep, display->first_row);
+ ptrdiff_t step_row = display->row_bytes;
+ int pass;
+
+ for (pass = 0; pass < passes; ++pass)
+ {
+ unsigned int startx, stepx, stepy;
+ png_uint_32 y;
+
+ if (png_ptr->interlaced == PNG_INTERLACE_ADAM7)
+ {
+ /* The row may be empty for a short image: */
+ if (PNG_PASS_COLS(width, pass) == 0)
+ continue;
+
+ startx = PNG_PASS_START_COL(pass);
+ stepx = PNG_PASS_COL_OFFSET(pass);
+ y = PNG_PASS_START_ROW(pass);
+ stepy = PNG_PASS_ROW_OFFSET(pass);
+ }
+
+ else
+ {
+ y = 0;
+ startx = 0;
+ stepx = stepy = 1;
+ }
+
+ for (; y<height; y += stepy)
+ {
+ png_bytep inrow = png_voidcast(png_bytep, display->local_row);
+ png_bytep outrow = first_row + y * step_row;
+ png_const_bytep end_row = outrow + width;
+
+ /* Read read the libpng data into the temporary buffer. */
+ png_read_row(png_ptr, inrow, NULL);
+
+ /* Now process the row according to the processing option, note
+ * that the caller verifies that the format of the libpng output
+ * data is as required.
+ */
+ outrow += startx;
+ switch (proc)
+ {
+ case PNG_CMAP_GA:
+ for (; outrow < end_row; outrow += stepx)
+ {
+ /* The data is always in the PNG order */
+ unsigned int gray = *inrow++;
+ unsigned int alpha = *inrow++;
+ unsigned int entry;
+
+ /* NOTE: this code is copied as a comment in
+ * make_ga_colormap above. Please update the
+ * comment if you change this code!
+ */
+ if (alpha > 229) /* opaque */
+ {
+ entry = (231 * gray + 128) >> 8;
+ }
+ else if (alpha < 26) /* transparent */
+ {
+ entry = 231;
+ }
+ else /* partially opaque */
+ {
+ entry = 226 + 6 * PNG_DIV51(alpha) + PNG_DIV51(gray);
+ }
+
+ *outrow = (png_byte)entry;
+ }
+ break;
+
+ case PNG_CMAP_TRANS:
+ for (; outrow < end_row; outrow += stepx)
+ {
+ png_byte gray = *inrow++;
+ png_byte alpha = *inrow++;
+
+ if (alpha == 0)
+ *outrow = PNG_CMAP_TRANS_BACKGROUND;
+
+ else if (gray != PNG_CMAP_TRANS_BACKGROUND)
+ *outrow = gray;
+
+ else
+ *outrow = (png_byte)(PNG_CMAP_TRANS_BACKGROUND+1);
+ }
+ break;
+
+ case PNG_CMAP_RGB:
+ for (; outrow < end_row; outrow += stepx)
+ {
+ *outrow = PNG_RGB_INDEX(inrow[0], inrow[1], inrow[2]);
+ inrow += 3;
+ }
+ break;
+
+ case PNG_CMAP_RGB_ALPHA:
+ for (; outrow < end_row; outrow += stepx)
+ {
+ unsigned int alpha = inrow[3];
+
+ /* Because the alpha entries only hold alpha==0.5 values
+ * split the processing at alpha==0.25 (64) and 0.75
+ * (196).
+ */
+
+ if (alpha >= 196)
+ *outrow = PNG_RGB_INDEX(inrow[0], inrow[1],
+ inrow[2]);
+
+ else if (alpha < 64)
+ *outrow = PNG_CMAP_RGB_ALPHA_BACKGROUND;
+
+ else
+ {
+ /* Likewise there are three entries for each of r, g
+ * and b. We could select the entry by popcount on
+ * the top two bits on those architectures that
+ * support it, this is what the code below does,
+ * crudely.
+ */
+ unsigned int back_i = PNG_CMAP_RGB_ALPHA_BACKGROUND+1;
+
+ /* Here are how the values map:
+ *
+ * 0x00 .. 0x3f -> 0
+ * 0x40 .. 0xbf -> 1
+ * 0xc0 .. 0xff -> 2
+ *
+ * So, as above with the explicit alpha checks, the
+ * breakpoints are at 64 and 196.
+ */
+ if (inrow[0] & 0x80) back_i += 9; /* red */
+ if (inrow[0] & 0x40) back_i += 9;
+ if (inrow[0] & 0x80) back_i += 3; /* green */
+ if (inrow[0] & 0x40) back_i += 3;
+ if (inrow[0] & 0x80) back_i += 1; /* blue */
+ if (inrow[0] & 0x40) back_i += 1;
+
+ *outrow = (png_byte)back_i;
+ }
+
+ inrow += 4;
+ }
+ break;
+
+ default:
+ break;
+ }
+ }
+ }
+ }
+
+ return 1;
+}
+
+static int
+png_image_read_colormapped(png_voidp argument)
+{
+ png_image_read_control *display = png_voidcast(png_image_read_control*,
+ argument);
+ png_imagep image = display->image;
+ png_controlp control = image->opaque;
+ png_structrp png_ptr = control->png_ptr;
+ png_inforp info_ptr = control->info_ptr;
+
+ int passes = 0; /* As a flag */
+
+ PNG_SKIP_CHUNKS(png_ptr);
+
+ /* Update the 'info' structure and make sure the result is as required; first
+ * make sure to turn on the interlace handling if it will be required
+ * (because it can't be turned on *after* the call to png_read_update_info!)
+ */
+ if (display->colormap_processing == PNG_CMAP_NONE)
+ passes = png_set_interlace_handling(png_ptr);
+
+ png_read_update_info(png_ptr, info_ptr);
+
+ /* The expected output can be deduced from the colormap_processing option. */
+ switch (display->colormap_processing)
+ {
+ case PNG_CMAP_NONE:
+ /* Output must be one channel and one byte per pixel, the output
+ * encoding can be anything.
+ */
+ if ((info_ptr->color_type == PNG_COLOR_TYPE_PALETTE ||
+ info_ptr->color_type == PNG_COLOR_TYPE_GRAY) &&
+ info_ptr->bit_depth == 8)
+ break;
+
+ goto bad_output;
+
+ case PNG_CMAP_TRANS:
+ case PNG_CMAP_GA:
+ /* Output must be two channels and the 'G' one must be sRGB, the latter
+ * can be checked with an exact number because it should have been set
+ * to this number above!
+ */
+ if (info_ptr->color_type == PNG_COLOR_TYPE_GRAY_ALPHA &&
+ info_ptr->bit_depth == 8 &&
+ png_ptr->screen_gamma == PNG_GAMMA_sRGB &&
+ image->colormap_entries == 256)
+ break;
+
+ goto bad_output;
+
+ case PNG_CMAP_RGB:
+ /* Output must be 8-bit sRGB encoded RGB */
+ if (info_ptr->color_type == PNG_COLOR_TYPE_RGB &&
+ info_ptr->bit_depth == 8 &&
+ png_ptr->screen_gamma == PNG_GAMMA_sRGB &&
+ image->colormap_entries == 216)
+ break;
+
+ goto bad_output;
+
+ case PNG_CMAP_RGB_ALPHA:
+ /* Output must be 8-bit sRGB encoded RGBA */
+ if (info_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA &&
+ info_ptr->bit_depth == 8 &&
+ png_ptr->screen_gamma == PNG_GAMMA_sRGB &&
+ image->colormap_entries == 244 /* 216 + 1 + 27 */)
+ break;
+
+ /* goto bad_output; */
+ /* FALL THROUGH */
+
+ default:
+ bad_output:
+ png_error(png_ptr, "bad color-map processing (internal error)");
+ }
+
+ /* Now read the rows. Do this here if it is possible to read directly into
+ * the output buffer, otherwise allocate a local row buffer of the maximum
+ * size libpng requires and call the relevant processing routine safely.
+ */
+ {
+ png_voidp first_row = display->buffer;
+ ptrdiff_t row_bytes = display->row_stride;
+
+ /* The following expression is designed to work correctly whether it gives
+ * a signed or an unsigned result.
+ */
+ if (row_bytes < 0)
+ {
+ char *ptr = png_voidcast(char*, first_row);
+ ptr += (image->height-1) * (-row_bytes);
+ first_row = png_voidcast(png_voidp, ptr);
+ }
+
+ display->first_row = first_row;
+ display->row_bytes = row_bytes;
+ }
+
+ if (passes == 0)
+ {
+ int result;
+ png_voidp row = png_malloc(png_ptr, png_get_rowbytes(png_ptr, info_ptr));
+
+ display->local_row = row;
+ result = png_safe_execute(image, png_image_read_and_map, display);
+ display->local_row = NULL;
+ png_free(png_ptr, row);
+
+ return result;
+ }
+
+ else
+ {
+ png_alloc_size_t row_bytes = display->row_bytes;
+
+ while (--passes >= 0)
+ {
+ png_uint_32 y = image->height;
+ png_bytep row = png_voidcast(png_bytep, display->first_row);
+
+ while (y-- > 0)
+ {
+ png_read_row(png_ptr, row, NULL);
+ row += row_bytes;
+ }
+ }
+
+ return 1;
+ }
+}
+
+/* Just the row reading part of png_image_read. */
+static int
+png_image_read_composite(png_voidp argument)
+{
+ png_image_read_control *display = png_voidcast(png_image_read_control*,
+ argument);
+ png_imagep image = display->image;
+ png_structrp png_ptr = image->opaque->png_ptr;
+ int passes;
+
+ switch (png_ptr->interlaced)
+ {
+ case PNG_INTERLACE_NONE:
+ passes = 1;
+ break;
+
+ case PNG_INTERLACE_ADAM7:
+ passes = PNG_INTERLACE_ADAM7_PASSES;
+ break;
+
+ default:
+ png_error(png_ptr, "unknown interlace type");
+ }
+
+ {
+ png_uint_32 height = image->height;
+ png_uint_32 width = image->width;
+ ptrdiff_t step_row = display->row_bytes;
+ unsigned int channels =
+ (image->format & PNG_FORMAT_FLAG_COLOR) != 0 ? 3 : 1;
+ int pass;
+
+ for (pass = 0; pass < passes; ++pass)
+ {
+ unsigned int startx, stepx, stepy;
+ png_uint_32 y;
+
+ if (png_ptr->interlaced == PNG_INTERLACE_ADAM7)
+ {
+ /* The row may be empty for a short image: */
+ if (PNG_PASS_COLS(width, pass) == 0)
+ continue;
+
+ startx = PNG_PASS_START_COL(pass) * channels;
+ stepx = PNG_PASS_COL_OFFSET(pass) * channels;
+ y = PNG_PASS_START_ROW(pass);
+ stepy = PNG_PASS_ROW_OFFSET(pass);
+ }
+
+ else
+ {
+ y = 0;
+ startx = 0;
+ stepx = channels;
+ stepy = 1;
+ }
+
+ for (; y<height; y += stepy)
+ {
+ png_bytep inrow = png_voidcast(png_bytep, display->local_row);
+ png_bytep outrow;
+ png_const_bytep end_row;
+
+ /* Read the row, which is packed: */
+ png_read_row(png_ptr, inrow, NULL);
+
+ outrow = png_voidcast(png_bytep, display->first_row);
+ outrow += y * step_row;
+ end_row = outrow + width * channels;
+
+ /* Now do the composition on each pixel in this row. */
+ outrow += startx;
+ for (; outrow < end_row; outrow += stepx)
+ {
+ png_byte alpha = inrow[channels];
+
+ if (alpha > 0) /* else no change to the output */
+ {
+ unsigned int c;
+
+ for (c=0; c<channels; ++c)
+ {
+ png_uint_32 component = inrow[c];
+
+ if (alpha < 255) /* else just use component */
+ {
+ /* This is PNG_OPTIMIZED_ALPHA, the component value
+ * is a linear 8-bit value. Combine this with the
+ * current outrow[c] value which is sRGB encoded.
+ * Arithmetic here is 16-bits to preserve the output
+ * values correctly.
+ */
+ component *= 257*255; /* =65535 */
+ component += (255-alpha)*png_sRGB_table[outrow[c]];
+
+ /* So 'component' is scaled by 255*65535 and is
+ * therefore appropriate for the sRGB to linear
+ * conversion table.
+ */
+ component = PNG_sRGB_FROM_LINEAR(component);
+ }
+
+ outrow[c] = (png_byte)component;
+ }
+ }
+
+ inrow += channels+1; /* components and alpha channel */
+ }
+ }
+ }
+ }
+
+ return 1;
+}
+
+/* The do_local_background case; called when all the following transforms are to
+ * be done:
+ *
+ * PNG_RGB_TO_GRAY
+ * PNG_COMPOSITE
+ * PNG_GAMMA
+ *
+ * This is a work-around for the fact that both the PNG_RGB_TO_GRAY and
+ * PNG_COMPOSITE code performs gamma correction, so we get double gamma
+ * correction. The fix-up is to prevent the PNG_COMPOSITE operation from
+ * happening inside libpng, so this routine sees an 8 or 16-bit gray+alpha
+ * row and handles the removal or pre-multiplication of the alpha channel.
+ */
+static int
+png_image_read_background(png_voidp argument)
+{
+ png_image_read_control *display = png_voidcast(png_image_read_control*,
+ argument);
+ png_imagep image = display->image;
+ png_structrp png_ptr = image->opaque->png_ptr;
+ png_inforp info_ptr = image->opaque->info_ptr;
+ png_uint_32 height = image->height;
+ png_uint_32 width = image->width;
+ int pass, passes;
+
+ /* Double check the convoluted logic below. We expect to get here with
+ * libpng doing rgb to gray and gamma correction but background processing
+ * left to the png_image_read_background function. The rows libpng produce
+ * might be 8 or 16-bit but should always have two channels; gray plus alpha.
+ */
+ if ((png_ptr->transformations & PNG_RGB_TO_GRAY) == 0)
+ png_error(png_ptr, "lost rgb to gray");
+
+ if ((png_ptr->transformations & PNG_COMPOSE) != 0)
+ png_error(png_ptr, "unexpected compose");
+
+ if (png_get_channels(png_ptr, info_ptr) != 2)
+ png_error(png_ptr, "lost/gained channels");
+
+ /* Expect the 8-bit case to always remove the alpha channel */
+ if ((image->format & PNG_FORMAT_FLAG_LINEAR) == 0 &&
+ (image->format & PNG_FORMAT_FLAG_ALPHA) != 0)
+ png_error(png_ptr, "unexpected 8-bit transformation");
+
+ switch (png_ptr->interlaced)
+ {
+ case PNG_INTERLACE_NONE:
+ passes = 1;
+ break;
+
+ case PNG_INTERLACE_ADAM7:
+ passes = PNG_INTERLACE_ADAM7_PASSES;
+ break;
+
+ default:
+ png_error(png_ptr, "unknown interlace type");
+ }
+
+ /* Use direct access to info_ptr here because otherwise the simplified API
+ * would require PNG_EASY_ACCESS_SUPPORTED (just for this.) Note this is
+ * checking the value after libpng expansions, not the original value in the
+ * PNG.
+ */
+ switch (info_ptr->bit_depth)
+ {
+ default:
+ png_error(png_ptr, "unexpected bit depth");
+ break;
+
+ case 8:
+ /* 8-bit sRGB gray values with an alpha channel; the alpha channel is
+ * to be removed by composing on a background: either the row if
+ * display->background is NULL or display->background->green if not.
+ * Unlike the code above ALPHA_OPTIMIZED has *not* been done.
+ */
+ {
+ png_bytep first_row = png_voidcast(png_bytep, display->first_row);
+ ptrdiff_t step_row = display->row_bytes;
+
+ for (pass = 0; pass < passes; ++pass)
+ {
+ png_bytep row = png_voidcast(png_bytep,
+ display->first_row);
+ unsigned int startx, stepx, stepy;
+ png_uint_32 y;
+
+ if (png_ptr->interlaced == PNG_INTERLACE_ADAM7)
+ {
+ /* The row may be empty for a short image: */
+ if (PNG_PASS_COLS(width, pass) == 0)
+ continue;
+
+ startx = PNG_PASS_START_COL(pass);
+ stepx = PNG_PASS_COL_OFFSET(pass);
+ y = PNG_PASS_START_ROW(pass);
+ stepy = PNG_PASS_ROW_OFFSET(pass);
+ }
+
+ else
+ {
+ y = 0;
+ startx = 0;
+ stepx = stepy = 1;
+ }
+
+ if (display->background == NULL)
+ {
+ for (; y<height; y += stepy)
+ {
+ png_bytep inrow = png_voidcast(png_bytep,
+ display->local_row);
+ png_bytep outrow = first_row + y * step_row;
+ png_const_bytep end_row = outrow + width;
+
+ /* Read the row, which is packed: */
+ png_read_row(png_ptr, inrow, NULL);
+
+ /* Now do the composition on each pixel in this row. */
+ outrow += startx;
+ for (; outrow < end_row; outrow += stepx)
+ {
+ png_byte alpha = inrow[1];
+
+ if (alpha > 0) /* else no change to the output */
+ {
+ png_uint_32 component = inrow[0];
+
+ if (alpha < 255) /* else just use component */
+ {
+ /* Since PNG_OPTIMIZED_ALPHA was not set it is
+ * necessary to invert the sRGB transfer
+ * function and multiply the alpha out.
+ */
+ component = png_sRGB_table[component] * alpha;
+ component += png_sRGB_table[outrow[0]] *
+ (255-alpha);
+ component = PNG_sRGB_FROM_LINEAR(component);
+ }
+
+ outrow[0] = (png_byte)component;
+ }
+
+ inrow += 2; /* gray and alpha channel */
+ }
+ }
+ }
+
+ else /* constant background value */
+ {
+ png_byte background8 = display->background->green;
+ png_uint_16 background = png_sRGB_table[background8];
+
+ for (; y<height; y += stepy)
+ {
+ png_bytep inrow = png_voidcast(png_bytep,
+ display->local_row);
+ png_bytep outrow = first_row + y * step_row;
+ png_const_bytep end_row = outrow + width;
+
+ /* Read the row, which is packed: */
+ png_read_row(png_ptr, inrow, NULL);
+
+ /* Now do the composition on each pixel in this row. */
+ outrow += startx;
+ for (; outrow < end_row; outrow += stepx)
+ {
+ png_byte alpha = inrow[1];
+
+ if (alpha > 0) /* else use background */
+ {
+ png_uint_32 component = inrow[0];
+
+ if (alpha < 255) /* else just use component */
+ {
+ component = png_sRGB_table[component] * alpha;
+ component += background * (255-alpha);
+ component = PNG_sRGB_FROM_LINEAR(component);
+ }
+
+ outrow[0] = (png_byte)component;
+ }
+
+ else
+ outrow[0] = background8;
+
+ inrow += 2; /* gray and alpha channel */
+ }
+
+ row += display->row_bytes;
+ }
+ }
+ }
+ }
+ break;
+
+ case 16:
+ /* 16-bit linear with pre-multiplied alpha; the pre-multiplication must
+ * still be done and, maybe, the alpha channel removed. This code also
+ * handles the alpha-first option.
+ */
+ {
+ png_uint_16p first_row = png_voidcast(png_uint_16p,
+ display->first_row);
+ /* The division by two is safe because the caller passed in a
+ * stride which was multiplied by 2 (below) to get row_bytes.
+ */
+ ptrdiff_t step_row = display->row_bytes / 2;
+ int preserve_alpha = (image->format & PNG_FORMAT_FLAG_ALPHA) != 0;
+ unsigned int outchannels = 1+preserve_alpha;
+ int swap_alpha = 0;
+
+# ifdef PNG_SIMPLIFIED_READ_AFIRST_SUPPORTED
+ if (preserve_alpha != 0 &&
+ (image->format & PNG_FORMAT_FLAG_AFIRST) != 0)
+ swap_alpha = 1;
+# endif
+
+ for (pass = 0; pass < passes; ++pass)
+ {
+ unsigned int startx, stepx, stepy;
+ png_uint_32 y;
+
+ /* The 'x' start and step are adjusted to output components here.
+ */
+ if (png_ptr->interlaced == PNG_INTERLACE_ADAM7)
+ {
+ /* The row may be empty for a short image: */
+ if (PNG_PASS_COLS(width, pass) == 0)
+ continue;
+
+ startx = PNG_PASS_START_COL(pass) * outchannels;
+ stepx = PNG_PASS_COL_OFFSET(pass) * outchannels;
+ y = PNG_PASS_START_ROW(pass);
+ stepy = PNG_PASS_ROW_OFFSET(pass);
+ }
+
+ else
+ {
+ y = 0;
+ startx = 0;
+ stepx = outchannels;
+ stepy = 1;
+ }
+
+ for (; y<height; y += stepy)
+ {
+ png_const_uint_16p inrow;
+ png_uint_16p outrow = first_row + y*step_row;
+ png_uint_16p end_row = outrow + width * outchannels;
+
+ /* Read the row, which is packed: */
+ png_read_row(png_ptr, png_voidcast(png_bytep,
+ display->local_row), NULL);
+ inrow = png_voidcast(png_const_uint_16p, display->local_row);
+
+ /* Now do the pre-multiplication on each pixel in this row.
+ */
+ outrow += startx;
+ for (; outrow < end_row; outrow += stepx)
+ {
+ png_uint_32 component = inrow[0];
+ png_uint_16 alpha = inrow[1];
+
+ if (alpha > 0) /* else 0 */
+ {
+ if (alpha < 65535) /* else just use component */
+ {
+ component *= alpha;
+ component += 32767;
+ component /= 65535;
+ }
+ }
+
+ else
+ component = 0;
+
+ outrow[swap_alpha] = (png_uint_16)component;
+ if (preserve_alpha != 0)
+ outrow[1 ^ swap_alpha] = alpha;
+
+ inrow += 2; /* components and alpha channel */
+ }
+ }
+ }
+ }
+ break;
+ }
+
+ return 1;
+}
+
+/* The guts of png_image_finish_read as a png_safe_execute callback. */
+static int
+png_image_read_direct(png_voidp argument)
+{
+ png_image_read_control *display = png_voidcast(png_image_read_control*,
+ argument);
+ png_imagep image = display->image;
+ png_structrp png_ptr = image->opaque->png_ptr;
+ png_inforp info_ptr = image->opaque->info_ptr;
+
+ png_uint_32 format = image->format;
+ int linear = (format & PNG_FORMAT_FLAG_LINEAR) != 0;
+ int do_local_compose = 0;
+ int do_local_background = 0; /* to avoid double gamma correction bug */
+ int passes = 0;
+
+ /* Add transforms to ensure the correct output format is produced then check
+ * that the required implementation support is there. Always expand; always
+ * need 8 bits minimum, no palette and expanded tRNS.
+ */
+ png_set_expand(png_ptr);
+
+ /* Now check the format to see if it was modified. */
+ {
+ png_uint_32 base_format = png_image_format(png_ptr) &
+ ~PNG_FORMAT_FLAG_COLORMAP /* removed by png_set_expand */;
+ png_uint_32 change = format ^ base_format;
+ png_fixed_point output_gamma;
+ int mode; /* alpha mode */
+
+ /* Do this first so that we have a record if rgb to gray is happening. */
+ if ((change & PNG_FORMAT_FLAG_COLOR) != 0)
+ {
+ /* gray<->color transformation required. */
+ if ((format & PNG_FORMAT_FLAG_COLOR) != 0)
+ png_set_gray_to_rgb(png_ptr);
+
+ else
+ {
+ /* libpng can't do both rgb to gray and
+ * background/pre-multiplication if there is also significant gamma
+ * correction, because both operations require linear colors and
+ * the code only supports one transform doing the gamma correction.
+ * Handle this by doing the pre-multiplication or background
+ * operation in this code, if necessary.
+ *
+ * TODO: fix this by rewriting pngrtran.c (!)
+ *
+ * For the moment (given that fixing this in pngrtran.c is an
+ * enormous change) 'do_local_background' is used to indicate that
+ * the problem exists.
+ */
+ if ((base_format & PNG_FORMAT_FLAG_ALPHA) != 0)
+ do_local_background = 1/*maybe*/;
+
+ png_set_rgb_to_gray_fixed(png_ptr, PNG_ERROR_ACTION_NONE,
+ PNG_RGB_TO_GRAY_DEFAULT, PNG_RGB_TO_GRAY_DEFAULT);
+ }
+
+ change &= ~PNG_FORMAT_FLAG_COLOR;
+ }
+
+ /* Set the gamma appropriately, linear for 16-bit input, sRGB otherwise.
+ */
+ {
+ png_fixed_point input_gamma_default;
+
+ if ((base_format & PNG_FORMAT_FLAG_LINEAR) != 0 &&
+ (image->flags & PNG_IMAGE_FLAG_16BIT_sRGB) == 0)
+ input_gamma_default = PNG_GAMMA_LINEAR;
+ else
+ input_gamma_default = PNG_DEFAULT_sRGB;
+
+ /* Call png_set_alpha_mode to set the default for the input gamma; the
+ * output gamma is set by a second call below.
+ */
+ png_set_alpha_mode_fixed(png_ptr, PNG_ALPHA_PNG, input_gamma_default);
+ }
+
+ if (linear != 0)
+ {
+ /* If there *is* an alpha channel in the input it must be multiplied
+ * out; use PNG_ALPHA_STANDARD, otherwise just use PNG_ALPHA_PNG.
+ */
+ if ((base_format & PNG_FORMAT_FLAG_ALPHA) != 0)
+ mode = PNG_ALPHA_STANDARD; /* associated alpha */
+
+ else
+ mode = PNG_ALPHA_PNG;
+
+ output_gamma = PNG_GAMMA_LINEAR;
+ }
+
+ else
+ {
+ mode = PNG_ALPHA_PNG;
+ output_gamma = PNG_DEFAULT_sRGB;
+ }
+
+ /* If 'do_local_background' is set check for the presence of gamma
+ * correction; this is part of the work-round for the libpng bug
+ * described above.
+ *
+ * TODO: fix libpng and remove this.
+ */
+ if (do_local_background != 0)
+ {
+ png_fixed_point gtest;
+
+ /* This is 'png_gamma_threshold' from pngrtran.c; the test used for
+ * gamma correction, the screen gamma hasn't been set on png_struct
+ * yet; it's set below. png_struct::gamma, however, is set to the
+ * final value.
+ */
+ if (png_muldiv(>est, output_gamma, png_ptr->colorspace.gamma,
+ PNG_FP_1) != 0 && png_gamma_significant(gtest) == 0)
+ do_local_background = 0;
+
+ else if (mode == PNG_ALPHA_STANDARD)
+ {
+ do_local_background = 2/*required*/;
+ mode = PNG_ALPHA_PNG; /* prevent libpng doing it */
+ }
+
+ /* else leave as 1 for the checks below */
+ }
+
+ /* If the bit-depth changes then handle that here. */
+ if ((change & PNG_FORMAT_FLAG_LINEAR) != 0)
+ {
+ if (linear != 0 /*16-bit output*/)
+ png_set_expand_16(png_ptr);
+
+ else /* 8-bit output */
+ png_set_scale_16(png_ptr);
+
+ change &= ~PNG_FORMAT_FLAG_LINEAR;
+ }
+
+ /* Now the background/alpha channel changes. */
+ if ((change & PNG_FORMAT_FLAG_ALPHA) != 0)
+ {
+ /* Removing an alpha channel requires composition for the 8-bit
+ * formats; for the 16-bit it is already done, above, by the
+ * pre-multiplication and the channel just needs to be stripped.
+ */
+ if ((base_format & PNG_FORMAT_FLAG_ALPHA) != 0)
+ {
+ /* If RGB->gray is happening the alpha channel must be left and the
+ * operation completed locally.
+ *
+ * TODO: fix libpng and remove this.
+ */
+ if (do_local_background != 0)
+ do_local_background = 2/*required*/;
+
+ /* 16-bit output: just remove the channel */
+ else if (linear != 0) /* compose on black (well, pre-multiply) */
+ png_set_strip_alpha(png_ptr);
+
+ /* 8-bit output: do an appropriate compose */
+ else if (display->background != NULL)
+ {
+ png_color_16 c;
+
+ c.index = 0; /*unused*/
+ c.red = display->background->red;
+ c.green = display->background->green;
+ c.blue = display->background->blue;
+ c.gray = display->background->green;
+
+ /* This is always an 8-bit sRGB value, using the 'green' channel
+ * for gray is much better than calculating the luminance here;
+ * we can get off-by-one errors in that calculation relative to
+ * the app expectations and that will show up in transparent
+ * pixels.
+ */
+ png_set_background_fixed(png_ptr, &c,
+ PNG_BACKGROUND_GAMMA_SCREEN, 0/*need_expand*/,
+ 0/*gamma: not used*/);
+ }
+
+ else /* compose on row: implemented below. */
+ {
+ do_local_compose = 1;
+ /* This leaves the alpha channel in the output, so it has to be
+ * removed by the code below. Set the encoding to the 'OPTIMIZE'
+ * one so the code only has to hack on the pixels that require
+ * composition.
+ */
+ mode = PNG_ALPHA_OPTIMIZED;
+ }
+ }
+
+ else /* output needs an alpha channel */
+ {
+ /* This is tricky because it happens before the swap operation has
+ * been accomplished; however, the swap does *not* swap the added
+ * alpha channel (weird API), so it must be added in the correct
+ * place.
+ */
+ png_uint_32 filler; /* opaque filler */
+ int where;
+
+ if (linear != 0)
+ filler = 65535;
+
+ else
+ filler = 255;
+
+# ifdef PNG_FORMAT_AFIRST_SUPPORTED
+ if ((format & PNG_FORMAT_FLAG_AFIRST) != 0)
+ {
+ where = PNG_FILLER_BEFORE;
+ change &= ~PNG_FORMAT_FLAG_AFIRST;
+ }
+
+ else
+# endif
+ where = PNG_FILLER_AFTER;
+
+ png_set_add_alpha(png_ptr, filler, where);
+ }
+
+ /* This stops the (irrelevant) call to swap_alpha below. */
+ change &= ~PNG_FORMAT_FLAG_ALPHA;
+ }
+
+ /* Now set the alpha mode correctly; this is always done, even if there is
+ * no alpha channel in either the input or the output because it correctly
+ * sets the output gamma.
+ */
+ png_set_alpha_mode_fixed(png_ptr, mode, output_gamma);
+
+# ifdef PNG_FORMAT_BGR_SUPPORTED
+ if ((change & PNG_FORMAT_FLAG_BGR) != 0)
+ {
+ /* Check only the output format; PNG is never BGR; don't do this if
+ * the output is gray, but fix up the 'format' value in that case.
+ */
+ if ((format & PNG_FORMAT_FLAG_COLOR) != 0)
+ png_set_bgr(png_ptr);
+
+ else
+ format &= ~PNG_FORMAT_FLAG_BGR;
+
+ change &= ~PNG_FORMAT_FLAG_BGR;
+ }
+# endif
+
+# ifdef PNG_FORMAT_AFIRST_SUPPORTED
+ if ((change & PNG_FORMAT_FLAG_AFIRST) != 0)
+ {
+ /* Only relevant if there is an alpha channel - it's particularly
+ * important to handle this correctly because do_local_compose may
+ * be set above and then libpng will keep the alpha channel for this
+ * code to remove.
+ */
+ if ((format & PNG_FORMAT_FLAG_ALPHA) != 0)
+ {
+ /* Disable this if doing a local background,
+ * TODO: remove this when local background is no longer required.
+ */
+ if (do_local_background != 2)
+ png_set_swap_alpha(png_ptr);
+ }
+
+ else
+ format &= ~PNG_FORMAT_FLAG_AFIRST;
+
+ change &= ~PNG_FORMAT_FLAG_AFIRST;
+ }
+# endif
+
+ /* If the *output* is 16-bit then we need to check for a byte-swap on this
+ * architecture.
+ */
+ if (linear != 0)
+ {
+ PNG_CONST png_uint_16 le = 0x0001;
+
+ if ((*(png_const_bytep) & le) != 0)
+ png_set_swap(png_ptr);
+ }
+
+ /* If change is not now 0 some transformation is missing - error out. */
+ if (change != 0)
+ png_error(png_ptr, "png_read_image: unsupported transformation");
+ }
+
+ PNG_SKIP_CHUNKS(png_ptr);
+
+ /* Update the 'info' structure and make sure the result is as required; first
+ * make sure to turn on the interlace handling if it will be required
+ * (because it can't be turned on *after* the call to png_read_update_info!)
+ *
+ * TODO: remove the do_local_background fixup below.
+ */
+ if (do_local_compose == 0 && do_local_background != 2)
+ passes = png_set_interlace_handling(png_ptr);
+
+ png_read_update_info(png_ptr, info_ptr);
+
+ {
+ png_uint_32 info_format = 0;
+
+ if ((info_ptr->color_type & PNG_COLOR_MASK_COLOR) != 0)
+ info_format |= PNG_FORMAT_FLAG_COLOR;
+
+ if ((info_ptr->color_type & PNG_COLOR_MASK_ALPHA) != 0)
+ {
+ /* do_local_compose removes this channel below. */
+ if (do_local_compose == 0)
+ {
+ /* do_local_background does the same if required. */
+ if (do_local_background != 2 ||
+ (format & PNG_FORMAT_FLAG_ALPHA) != 0)
+ info_format |= PNG_FORMAT_FLAG_ALPHA;
+ }
+ }
+
+ else if (do_local_compose != 0) /* internal error */
+ png_error(png_ptr, "png_image_read: alpha channel lost");
+
+ if (info_ptr->bit_depth == 16)
+ info_format |= PNG_FORMAT_FLAG_LINEAR;
+
+# ifdef PNG_FORMAT_BGR_SUPPORTED
+ if ((png_ptr->transformations & PNG_BGR) != 0)
+ info_format |= PNG_FORMAT_FLAG_BGR;
+# endif
+
+# ifdef PNG_FORMAT_AFIRST_SUPPORTED
+ if (do_local_background == 2)
+ {
+ if ((format & PNG_FORMAT_FLAG_AFIRST) != 0)
+ info_format |= PNG_FORMAT_FLAG_AFIRST;
+ }
+
+ if ((png_ptr->transformations & PNG_SWAP_ALPHA) != 0 ||
+ ((png_ptr->transformations & PNG_ADD_ALPHA) != 0 &&
+ (png_ptr->flags & PNG_FLAG_FILLER_AFTER) == 0))
+ {
+ if (do_local_background == 2)
+ png_error(png_ptr, "unexpected alpha swap transformation");
+
+ info_format |= PNG_FORMAT_FLAG_AFIRST;
+ }
+# endif
+
+ /* This is actually an internal error. */
+ if (info_format != format)
+ png_error(png_ptr, "png_read_image: invalid transformations");
+ }
+
+ /* Now read the rows. If do_local_compose is set then it is necessary to use
+ * a local row buffer. The output will be GA, RGBA or BGRA and must be
+ * converted to G, RGB or BGR as appropriate. The 'local_row' member of the
+ * display acts as a flag.
+ */
+ {
+ png_voidp first_row = display->buffer;
+ ptrdiff_t row_bytes = display->row_stride;
+
+ if (linear != 0)
+ row_bytes *= 2;
+
+ /* The following expression is designed to work correctly whether it gives
+ * a signed or an unsigned result.
+ */
+ if (row_bytes < 0)
+ {
+ char *ptr = png_voidcast(char*, first_row);
+ ptr += (image->height-1) * (-row_bytes);
+ first_row = png_voidcast(png_voidp, ptr);
+ }
+
+ display->first_row = first_row;
+ display->row_bytes = row_bytes;
+ }
+
+ if (do_local_compose != 0)
+ {
+ int result;
+ png_voidp row = png_malloc(png_ptr, png_get_rowbytes(png_ptr, info_ptr));
+
+ display->local_row = row;
+ result = png_safe_execute(image, png_image_read_composite, display);
+ display->local_row = NULL;
+ png_free(png_ptr, row);
+
+ return result;
+ }
+
+ else if (do_local_background == 2)
+ {
+ int result;
+ png_voidp row = png_malloc(png_ptr, png_get_rowbytes(png_ptr, info_ptr));
+
+ display->local_row = row;
+ result = png_safe_execute(image, png_image_read_background, display);
+ display->local_row = NULL;
+ png_free(png_ptr, row);
+
+ return result;
+ }
+
+ else
+ {
+ png_alloc_size_t row_bytes = display->row_bytes;
+
+ while (--passes >= 0)
+ {
+ png_uint_32 y = image->height;
+ png_bytep row = png_voidcast(png_bytep, display->first_row);
+
+ while (y-- > 0)
+ {
+ png_read_row(png_ptr, row, NULL);
+ row += row_bytes;
+ }
+ }
+
+ return 1;
+ }
+}
+
+int PNGAPI
+png_image_finish_read(png_imagep image, png_const_colorp background,
+ void *buffer, png_int_32 row_stride, void *colormap)
+{
+ if (image != NULL && image->version == PNG_IMAGE_VERSION)
+ {
+ png_uint_32 check;
+
+ if (row_stride == 0)
+ row_stride = PNG_IMAGE_ROW_STRIDE(*image);
+
+ if (row_stride < 0)
+ check = -row_stride;
+
+ else
+ check = row_stride;
+
+ if (image->opaque != NULL && buffer != NULL &&
+ check >= PNG_IMAGE_ROW_STRIDE(*image))
+ {
+ if ((image->format & PNG_FORMAT_FLAG_COLORMAP) == 0 ||
+ (image->colormap_entries > 0 && colormap != NULL))
+ {
+ int result;
+ png_image_read_control display;
+
+ memset(&display, 0, (sizeof display));
+ display.image = image;
+ display.buffer = buffer;
+ display.row_stride = row_stride;
+ display.colormap = colormap;
+ display.background = background;
+ display.local_row = NULL;
+
+ /* Choose the correct 'end' routine; for the color-map case all the
+ * setup has already been done.
+ */
+ if ((image->format & PNG_FORMAT_FLAG_COLORMAP) != 0)
+ result =
+ png_safe_execute(image, png_image_read_colormap, &display) &&
+ png_safe_execute(image, png_image_read_colormapped, &display);
+
+ else
+ result =
+ png_safe_execute(image, png_image_read_direct, &display);
+
+ png_image_free(image);
+ return result;
+ }
+
+ else
+ return png_image_error(image,
+ "png_image_finish_read[color-map]: no color-map");
+ }
+
+ else
+ return png_image_error(image,
+ "png_image_finish_read: invalid argument");
+ }
+
+ else if (image != NULL)
+ return png_image_error(image,
+ "png_image_finish_read: damaged PNG_IMAGE_VERSION");
+
+ return 0;
+}
+
+#endif /* SIMPLIFIED_READ */
+#endif /* READ */
--- /dev/null
+
+/* pngrio.c - functions for data input
+ *
+ * Last changed in libpng 1.6.17 [March 26, 2015]
+ * Copyright (c) 1998-2015 Glenn Randers-Pehrson
+ * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
+ * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ *
+ * This file provides a location for all input. Users who need
+ * special handling are expected to write a function that has the same
+ * arguments as this and performs a similar function, but that possibly
+ * has a different input method. Note that you shouldn't change this
+ * function, but rather write a replacement function and then make
+ * libpng use it at run time with png_set_read_fn(...).
+ */
+
+#include "pngpriv.h"
+
+#ifdef PNG_READ_SUPPORTED
+
+/* Read the data from whatever input you are using. The default routine
+ * reads from a file pointer. Note that this routine sometimes gets called
+ * with very small lengths, so you should implement some kind of simple
+ * buffering if you are using unbuffered reads. This should never be asked
+ * to read more than 64K on a 16 bit machine.
+ */
+void /* PRIVATE */
+png_read_data(png_structrp png_ptr, png_bytep data, png_size_t length)
+{
+ png_debug1(4, "reading %d bytes", (int)length);
+
+ if (png_ptr->read_data_fn != NULL)
+ (*(png_ptr->read_data_fn))(png_ptr, data, length);
+
+ else
+ png_error(png_ptr, "Call to NULL read function");
+}
+
+#ifdef PNG_STDIO_SUPPORTED
+/* This is the function that does the actual reading of data. If you are
+ * not reading from a standard C stream, you should create a replacement
+ * read_data function and use it at run time with png_set_read_fn(), rather
+ * than changing the library.
+ */
+void PNGCBAPI
+png_default_read_data(png_structp png_ptr, png_bytep data, png_size_t length)
+{
+ png_size_t check;
+
+ if (png_ptr == NULL)
+ return;
+
+ /* fread() returns 0 on error, so it is OK to store this in a png_size_t
+ * instead of an int, which is what fread() actually returns.
+ */
+ check = fread(data, 1, length, png_voidcast(png_FILE_p, png_ptr->io_ptr));
+
+ if (check != length)
+ png_error(png_ptr, "Read Error");
+}
+#endif
+
+/* This function allows the application to supply a new input function
+ * for libpng if standard C streams aren't being used.
+ *
+ * This function takes as its arguments:
+ *
+ * png_ptr - pointer to a png input data structure
+ *
+ * io_ptr - pointer to user supplied structure containing info about
+ * the input functions. May be NULL.
+ *
+ * read_data_fn - pointer to a new input function that takes as its
+ * arguments a pointer to a png_struct, a pointer to
+ * a location where input data can be stored, and a 32-bit
+ * unsigned int that is the number of bytes to be read.
+ * To exit and output any fatal error messages the new write
+ * function should call png_error(png_ptr, "Error msg").
+ * May be NULL, in which case libpng's default function will
+ * be used.
+ */
+void PNGAPI
+png_set_read_fn(png_structrp png_ptr, png_voidp io_ptr,
+ png_rw_ptr read_data_fn)
+{
+ if (png_ptr == NULL)
+ return;
+
+ png_ptr->io_ptr = io_ptr;
+
+#ifdef PNG_STDIO_SUPPORTED
+ if (read_data_fn != NULL)
+ png_ptr->read_data_fn = read_data_fn;
+
+ else
+ png_ptr->read_data_fn = png_default_read_data;
+#else
+ png_ptr->read_data_fn = read_data_fn;
+#endif
+
+#ifdef PNG_WRITE_SUPPORTED
+ /* It is an error to write to a read device */
+ if (png_ptr->write_data_fn != NULL)
+ {
+ png_ptr->write_data_fn = NULL;
+ png_warning(png_ptr,
+ "Can't set both read_data_fn and write_data_fn in the"
+ " same structure");
+ }
+#endif
+
+#ifdef PNG_WRITE_FLUSH_SUPPORTED
+ png_ptr->output_flush_fn = NULL;
+#endif
+}
+#endif /* READ */
--- /dev/null
+
+/* pngrtran.c - transforms the data in a row for PNG readers
+ *
+ * Last changed in libpng 1.6.17 [March 26, 2015]
+ * Copyright (c) 1998-2015 Glenn Randers-Pehrson
+ * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
+ * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ *
+ * This file contains functions optionally called by an application
+ * in order to tell libpng how to handle data when reading a PNG.
+ * Transformations that are used in both reading and writing are
+ * in pngtrans.c.
+ */
+
+#include "pngpriv.h"
+
+#ifdef PNG_READ_SUPPORTED
+
+/* Set the action on getting a CRC error for an ancillary or critical chunk. */
+void PNGAPI
+png_set_crc_action(png_structrp png_ptr, int crit_action, int ancil_action)
+{
+ png_debug(1, "in png_set_crc_action");
+
+ if (png_ptr == NULL)
+ return;
+
+ /* Tell libpng how we react to CRC errors in critical chunks */
+ switch (crit_action)
+ {
+ case PNG_CRC_NO_CHANGE: /* Leave setting as is */
+ break;
+
+ case PNG_CRC_WARN_USE: /* Warn/use data */
+ png_ptr->flags &= ~PNG_FLAG_CRC_CRITICAL_MASK;
+ png_ptr->flags |= PNG_FLAG_CRC_CRITICAL_USE;
+ break;
+
+ case PNG_CRC_QUIET_USE: /* Quiet/use data */
+ png_ptr->flags &= ~PNG_FLAG_CRC_CRITICAL_MASK;
+ png_ptr->flags |= PNG_FLAG_CRC_CRITICAL_USE |
+ PNG_FLAG_CRC_CRITICAL_IGNORE;
+ break;
+
+ case PNG_CRC_WARN_DISCARD: /* Not a valid action for critical data */
+ png_warning(png_ptr,
+ "Can't discard critical data on CRC error");
+ case PNG_CRC_ERROR_QUIT: /* Error/quit */
+
+ case PNG_CRC_DEFAULT:
+ default:
+ png_ptr->flags &= ~PNG_FLAG_CRC_CRITICAL_MASK;
+ break;
+ }
+
+ /* Tell libpng how we react to CRC errors in ancillary chunks */
+ switch (ancil_action)
+ {
+ case PNG_CRC_NO_CHANGE: /* Leave setting as is */
+ break;
+
+ case PNG_CRC_WARN_USE: /* Warn/use data */
+ png_ptr->flags &= ~PNG_FLAG_CRC_ANCILLARY_MASK;
+ png_ptr->flags |= PNG_FLAG_CRC_ANCILLARY_USE;
+ break;
+
+ case PNG_CRC_QUIET_USE: /* Quiet/use data */
+ png_ptr->flags &= ~PNG_FLAG_CRC_ANCILLARY_MASK;
+ png_ptr->flags |= PNG_FLAG_CRC_ANCILLARY_USE |
+ PNG_FLAG_CRC_ANCILLARY_NOWARN;
+ break;
+
+ case PNG_CRC_ERROR_QUIT: /* Error/quit */
+ png_ptr->flags &= ~PNG_FLAG_CRC_ANCILLARY_MASK;
+ png_ptr->flags |= PNG_FLAG_CRC_ANCILLARY_NOWARN;
+ break;
+
+ case PNG_CRC_WARN_DISCARD: /* Warn/discard data */
+
+ case PNG_CRC_DEFAULT:
+ default:
+ png_ptr->flags &= ~PNG_FLAG_CRC_ANCILLARY_MASK;
+ break;
+ }
+}
+
+#ifdef PNG_READ_TRANSFORMS_SUPPORTED
+/* Is it OK to set a transformation now? Only if png_start_read_image or
+ * png_read_update_info have not been called. It is not necessary for the IHDR
+ * to have been read in all cases; the need_IHDR parameter allows for this
+ * check too.
+ */
+static int
+png_rtran_ok(png_structrp png_ptr, int need_IHDR)
+{
+ if (png_ptr != NULL)
+ {
+ if ((png_ptr->flags & PNG_FLAG_ROW_INIT) != 0)
+ png_app_error(png_ptr,
+ "invalid after png_start_read_image or png_read_update_info");
+
+ else if (need_IHDR && (png_ptr->mode & PNG_HAVE_IHDR) == 0)
+ png_app_error(png_ptr, "invalid before the PNG header has been read");
+
+ else
+ {
+ /* Turn on failure to initialize correctly for all transforms. */
+ png_ptr->flags |= PNG_FLAG_DETECT_UNINITIALIZED;
+
+ return 1; /* Ok */
+ }
+ }
+
+ return 0; /* no png_error possible! */
+}
+#endif
+
+#ifdef PNG_READ_BACKGROUND_SUPPORTED
+/* Handle alpha and tRNS via a background color */
+void PNGFAPI
+png_set_background_fixed(png_structrp png_ptr,
+ png_const_color_16p background_color, int background_gamma_code,
+ int need_expand, png_fixed_point background_gamma)
+{
+ png_debug(1, "in png_set_background_fixed");
+
+ if (png_rtran_ok(png_ptr, 0) == 0 || background_color == NULL)
+ return;
+
+ if (background_gamma_code == PNG_BACKGROUND_GAMMA_UNKNOWN)
+ {
+ png_warning(png_ptr, "Application must supply a known background gamma");
+ return;
+ }
+
+ png_ptr->transformations |= PNG_COMPOSE | PNG_STRIP_ALPHA;
+ png_ptr->transformations &= ~PNG_ENCODE_ALPHA;
+ png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA;
+
+ png_ptr->background = *background_color;
+ png_ptr->background_gamma = background_gamma;
+ png_ptr->background_gamma_type = (png_byte)(background_gamma_code);
+ if (need_expand != 0)
+ png_ptr->transformations |= PNG_BACKGROUND_EXPAND;
+ else
+ png_ptr->transformations &= ~PNG_BACKGROUND_EXPAND;
+}
+
+# ifdef PNG_FLOATING_POINT_SUPPORTED
+void PNGAPI
+png_set_background(png_structrp png_ptr,
+ png_const_color_16p background_color, int background_gamma_code,
+ int need_expand, double background_gamma)
+{
+ png_set_background_fixed(png_ptr, background_color, background_gamma_code,
+ need_expand, png_fixed(png_ptr, background_gamma, "png_set_background"));
+}
+# endif /* FLOATING_POINT */
+#endif /* READ_BACKGROUND */
+
+/* Scale 16-bit depth files to 8-bit depth. If both of these are set then the
+ * one that pngrtran does first (scale) happens. This is necessary to allow the
+ * TRANSFORM and API behavior to be somewhat consistent, and it's simpler.
+ */
+#ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
+void PNGAPI
+png_set_scale_16(png_structrp png_ptr)
+{
+ png_debug(1, "in png_set_scale_16");
+
+ if (png_rtran_ok(png_ptr, 0) == 0)
+ return;
+
+ png_ptr->transformations |= PNG_SCALE_16_TO_8;
+}
+#endif
+
+#ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
+/* Chop 16-bit depth files to 8-bit depth */
+void PNGAPI
+png_set_strip_16(png_structrp png_ptr)
+{
+ png_debug(1, "in png_set_strip_16");
+
+ if (png_rtran_ok(png_ptr, 0) == 0)
+ return;
+
+ png_ptr->transformations |= PNG_16_TO_8;
+}
+#endif
+
+#ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
+void PNGAPI
+png_set_strip_alpha(png_structrp png_ptr)
+{
+ png_debug(1, "in png_set_strip_alpha");
+
+ if (png_rtran_ok(png_ptr, 0) == 0)
+ return;
+
+ png_ptr->transformations |= PNG_STRIP_ALPHA;
+}
+#endif
+
+#if defined(PNG_READ_ALPHA_MODE_SUPPORTED) || defined(PNG_READ_GAMMA_SUPPORTED)
+static png_fixed_point
+translate_gamma_flags(png_structrp png_ptr, png_fixed_point output_gamma,
+ int is_screen)
+{
+ /* Check for flag values. The main reason for having the old Mac value as a
+ * flag is that it is pretty near impossible to work out what the correct
+ * value is from Apple documentation - a working Mac system is needed to
+ * discover the value!
+ */
+ if (output_gamma == PNG_DEFAULT_sRGB ||
+ output_gamma == PNG_FP_1 / PNG_DEFAULT_sRGB)
+ {
+ /* If there is no sRGB support this just sets the gamma to the standard
+ * sRGB value. (This is a side effect of using this function!)
+ */
+# ifdef PNG_READ_sRGB_SUPPORTED
+ png_ptr->flags |= PNG_FLAG_ASSUME_sRGB;
+# else
+ PNG_UNUSED(png_ptr)
+# endif
+ if (is_screen != 0)
+ output_gamma = PNG_GAMMA_sRGB;
+ else
+ output_gamma = PNG_GAMMA_sRGB_INVERSE;
+ }
+
+ else if (output_gamma == PNG_GAMMA_MAC_18 ||
+ output_gamma == PNG_FP_1 / PNG_GAMMA_MAC_18)
+ {
+ if (is_screen != 0)
+ output_gamma = PNG_GAMMA_MAC_OLD;
+ else
+ output_gamma = PNG_GAMMA_MAC_INVERSE;
+ }
+
+ return output_gamma;
+}
+
+# ifdef PNG_FLOATING_POINT_SUPPORTED
+static png_fixed_point
+convert_gamma_value(png_structrp png_ptr, double output_gamma)
+{
+ /* The following silently ignores cases where fixed point (times 100,000)
+ * gamma values are passed to the floating point API. This is safe and it
+ * means the fixed point constants work just fine with the floating point
+ * API. The alternative would just lead to undetected errors and spurious
+ * bug reports. Negative values fail inside the _fixed API unless they
+ * correspond to the flag values.
+ */
+ if (output_gamma > 0 && output_gamma < 128)
+ output_gamma *= PNG_FP_1;
+
+ /* This preserves -1 and -2 exactly: */
+ output_gamma = floor(output_gamma + .5);
+
+ if (output_gamma > PNG_FP_MAX || output_gamma < PNG_FP_MIN)
+ png_fixed_error(png_ptr, "gamma value");
+
+ return (png_fixed_point)output_gamma;
+}
+# endif
+#endif /* READ_ALPHA_MODE || READ_GAMMA */
+
+#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
+void PNGFAPI
+png_set_alpha_mode_fixed(png_structrp png_ptr, int mode,
+ png_fixed_point output_gamma)
+{
+ int compose = 0;
+ png_fixed_point file_gamma;
+
+ png_debug(1, "in png_set_alpha_mode");
+
+ if (png_rtran_ok(png_ptr, 0) == 0)
+ return;
+
+ output_gamma = translate_gamma_flags(png_ptr, output_gamma, 1/*screen*/);
+
+ /* Validate the value to ensure it is in a reasonable range. The value
+ * is expected to be 1 or greater, but this range test allows for some
+ * viewing correction values. The intent is to weed out users of this API
+ * who use the inverse of the gamma value accidentally! Since some of these
+ * values are reasonable this may have to be changed.
+ */
+ if (output_gamma < 70000 || output_gamma > 300000)
+ png_error(png_ptr, "output gamma out of expected range");
+
+ /* The default file gamma is the inverse of the output gamma; the output
+ * gamma may be changed below so get the file value first:
+ */
+ file_gamma = png_reciprocal(output_gamma);
+
+ /* There are really 8 possibilities here, composed of any combination
+ * of:
+ *
+ * premultiply the color channels
+ * do not encode non-opaque pixels
+ * encode the alpha as well as the color channels
+ *
+ * The differences disappear if the input/output ('screen') gamma is 1.0,
+ * because then the encoding is a no-op and there is only the choice of
+ * premultiplying the color channels or not.
+ *
+ * png_set_alpha_mode and png_set_background interact because both use
+ * png_compose to do the work. Calling both is only useful when
+ * png_set_alpha_mode is used to set the default mode - PNG_ALPHA_PNG - along
+ * with a default gamma value. Otherwise PNG_COMPOSE must not be set.
+ */
+ switch (mode)
+ {
+ case PNG_ALPHA_PNG: /* default: png standard */
+ /* No compose, but it may be set by png_set_background! */
+ png_ptr->transformations &= ~PNG_ENCODE_ALPHA;
+ png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA;
+ break;
+
+ case PNG_ALPHA_ASSOCIATED: /* color channels premultiplied */
+ compose = 1;
+ png_ptr->transformations &= ~PNG_ENCODE_ALPHA;
+ png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA;
+ /* The output is linear: */
+ output_gamma = PNG_FP_1;
+ break;
+
+ case PNG_ALPHA_OPTIMIZED: /* associated, non-opaque pixels linear */
+ compose = 1;
+ png_ptr->transformations &= ~PNG_ENCODE_ALPHA;
+ png_ptr->flags |= PNG_FLAG_OPTIMIZE_ALPHA;
+ /* output_gamma records the encoding of opaque pixels! */
+ break;
+
+ case PNG_ALPHA_BROKEN: /* associated, non-linear, alpha encoded */
+ compose = 1;
+ png_ptr->transformations |= PNG_ENCODE_ALPHA;
+ png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA;
+ break;
+
+ default:
+ png_error(png_ptr, "invalid alpha mode");
+ }
+
+ /* Only set the default gamma if the file gamma has not been set (this has
+ * the side effect that the gamma in a second call to png_set_alpha_mode will
+ * be ignored.)
+ */
+ if (png_ptr->colorspace.gamma == 0)
+ {
+ png_ptr->colorspace.gamma = file_gamma;
+ png_ptr->colorspace.flags |= PNG_COLORSPACE_HAVE_GAMMA;
+ }
+
+ /* But always set the output gamma: */
+ png_ptr->screen_gamma = output_gamma;
+
+ /* Finally, if pre-multiplying, set the background fields to achieve the
+ * desired result.
+ */
+ if (compose != 0)
+ {
+ /* And obtain alpha pre-multiplication by composing on black: */
+ memset(&png_ptr->background, 0, (sizeof png_ptr->background));
+ png_ptr->background_gamma = png_ptr->colorspace.gamma; /* just in case */
+ png_ptr->background_gamma_type = PNG_BACKGROUND_GAMMA_FILE;
+ png_ptr->transformations &= ~PNG_BACKGROUND_EXPAND;
+
+ if ((png_ptr->transformations & PNG_COMPOSE) != 0)
+ png_error(png_ptr,
+ "conflicting calls to set alpha mode and background");
+
+ png_ptr->transformations |= PNG_COMPOSE;
+ }
+}
+
+# ifdef PNG_FLOATING_POINT_SUPPORTED
+void PNGAPI
+png_set_alpha_mode(png_structrp png_ptr, int mode, double output_gamma)
+{
+ png_set_alpha_mode_fixed(png_ptr, mode, convert_gamma_value(png_ptr,
+ output_gamma));
+}
+# endif
+#endif
+
+#ifdef PNG_READ_QUANTIZE_SUPPORTED
+/* Dither file to 8-bit. Supply a palette, the current number
+ * of elements in the palette, the maximum number of elements
+ * allowed, and a histogram if possible. If the current number
+ * of colors is greater than the maximum number, the palette will be
+ * modified to fit in the maximum number. "full_quantize" indicates
+ * whether we need a quantizing cube set up for RGB images, or if we
+ * simply are reducing the number of colors in a paletted image.
+ */
+
+typedef struct png_dsort_struct
+{
+ struct png_dsort_struct * next;
+ png_byte left;
+ png_byte right;
+} png_dsort;
+typedef png_dsort * png_dsortp;
+typedef png_dsort * * png_dsortpp;
+
+void PNGAPI
+png_set_quantize(png_structrp png_ptr, png_colorp palette,
+ int num_palette, int maximum_colors, png_const_uint_16p histogram,
+ int full_quantize)
+{
+ png_debug(1, "in png_set_quantize");
+
+ if (png_rtran_ok(png_ptr, 0) == 0)
+ return;
+
+ png_ptr->transformations |= PNG_QUANTIZE;
+
+ if (full_quantize == 0)
+ {
+ int i;
+
+ png_ptr->quantize_index = (png_bytep)png_malloc(png_ptr,
+ (png_uint_32)(num_palette * (sizeof (png_byte))));
+ for (i = 0; i < num_palette; i++)
+ png_ptr->quantize_index[i] = (png_byte)i;
+ }
+
+ if (num_palette > maximum_colors)
+ {
+ if (histogram != NULL)
+ {
+ /* This is easy enough, just throw out the least used colors.
+ * Perhaps not the best solution, but good enough.
+ */
+
+ int i;
+
+ /* Initialize an array to sort colors */
+ png_ptr->quantize_sort = (png_bytep)png_malloc(png_ptr,
+ (png_uint_32)(num_palette * (sizeof (png_byte))));
+
+ /* Initialize the quantize_sort array */
+ for (i = 0; i < num_palette; i++)
+ png_ptr->quantize_sort[i] = (png_byte)i;
+
+ /* Find the least used palette entries by starting a
+ * bubble sort, and running it until we have sorted
+ * out enough colors. Note that we don't care about
+ * sorting all the colors, just finding which are
+ * least used.
+ */
+
+ for (i = num_palette - 1; i >= maximum_colors; i--)
+ {
+ int done; /* To stop early if the list is pre-sorted */
+ int j;
+
+ done = 1;
+ for (j = 0; j < i; j++)
+ {
+ if (histogram[png_ptr->quantize_sort[j]]
+ < histogram[png_ptr->quantize_sort[j + 1]])
+ {
+ png_byte t;
+
+ t = png_ptr->quantize_sort[j];
+ png_ptr->quantize_sort[j] = png_ptr->quantize_sort[j + 1];
+ png_ptr->quantize_sort[j + 1] = t;
+ done = 0;
+ }
+ }
+
+ if (done != 0)
+ break;
+ }
+
+ /* Swap the palette around, and set up a table, if necessary */
+ if (full_quantize != 0)
+ {
+ int j = num_palette;
+
+ /* Put all the useful colors within the max, but don't
+ * move the others.
+ */
+ for (i = 0; i < maximum_colors; i++)
+ {
+ if ((int)png_ptr->quantize_sort[i] >= maximum_colors)
+ {
+ do
+ j--;
+ while ((int)png_ptr->quantize_sort[j] >= maximum_colors);
+
+ palette[i] = palette[j];
+ }
+ }
+ }
+ else
+ {
+ int j = num_palette;
+
+ /* Move all the used colors inside the max limit, and
+ * develop a translation table.
+ */
+ for (i = 0; i < maximum_colors; i++)
+ {
+ /* Only move the colors we need to */
+ if ((int)png_ptr->quantize_sort[i] >= maximum_colors)
+ {
+ png_color tmp_color;
+
+ do
+ j--;
+ while ((int)png_ptr->quantize_sort[j] >= maximum_colors);
+
+ tmp_color = palette[j];
+ palette[j] = palette[i];
+ palette[i] = tmp_color;
+ /* Indicate where the color went */
+ png_ptr->quantize_index[j] = (png_byte)i;
+ png_ptr->quantize_index[i] = (png_byte)j;
+ }
+ }
+
+ /* Find closest color for those colors we are not using */
+ for (i = 0; i < num_palette; i++)
+ {
+ if ((int)png_ptr->quantize_index[i] >= maximum_colors)
+ {
+ int min_d, k, min_k, d_index;
+
+ /* Find the closest color to one we threw out */
+ d_index = png_ptr->quantize_index[i];
+ min_d = PNG_COLOR_DIST(palette[d_index], palette[0]);
+ for (k = 1, min_k = 0; k < maximum_colors; k++)
+ {
+ int d;
+
+ d = PNG_COLOR_DIST(palette[d_index], palette[k]);
+
+ if (d < min_d)
+ {
+ min_d = d;
+ min_k = k;
+ }
+ }
+ /* Point to closest color */
+ png_ptr->quantize_index[i] = (png_byte)min_k;
+ }
+ }
+ }
+ png_free(png_ptr, png_ptr->quantize_sort);
+ png_ptr->quantize_sort = NULL;
+ }
+ else
+ {
+ /* This is much harder to do simply (and quickly). Perhaps
+ * we need to go through a median cut routine, but those
+ * don't always behave themselves with only a few colors
+ * as input. So we will just find the closest two colors,
+ * and throw out one of them (chosen somewhat randomly).
+ * [We don't understand this at all, so if someone wants to
+ * work on improving it, be our guest - AED, GRP]
+ */
+ int i;
+ int max_d;
+ int num_new_palette;
+ png_dsortp t;
+ png_dsortpp hash;
+
+ t = NULL;
+
+ /* Initialize palette index arrays */
+ png_ptr->index_to_palette = (png_bytep)png_malloc(png_ptr,
+ (png_uint_32)(num_palette * (sizeof (png_byte))));
+ png_ptr->palette_to_index = (png_bytep)png_malloc(png_ptr,
+ (png_uint_32)(num_palette * (sizeof (png_byte))));
+
+ /* Initialize the sort array */
+ for (i = 0; i < num_palette; i++)
+ {
+ png_ptr->index_to_palette[i] = (png_byte)i;
+ png_ptr->palette_to_index[i] = (png_byte)i;
+ }
+
+ hash = (png_dsortpp)png_calloc(png_ptr, (png_uint_32)(769 *
+ (sizeof (png_dsortp))));
+
+ num_new_palette = num_palette;
+
+ /* Initial wild guess at how far apart the farthest pixel
+ * pair we will be eliminating will be. Larger
+ * numbers mean more areas will be allocated, Smaller
+ * numbers run the risk of not saving enough data, and
+ * having to do this all over again.
+ *
+ * I have not done extensive checking on this number.
+ */
+ max_d = 96;
+
+ while (num_new_palette > maximum_colors)
+ {
+ for (i = 0; i < num_new_palette - 1; i++)
+ {
+ int j;
+
+ for (j = i + 1; j < num_new_palette; j++)
+ {
+ int d;
+
+ d = PNG_COLOR_DIST(palette[i], palette[j]);
+
+ if (d <= max_d)
+ {
+
+ t = (png_dsortp)png_malloc_warn(png_ptr,
+ (png_uint_32)(sizeof (png_dsort)));
+
+ if (t == NULL)
+ break;
+
+ t->next = hash[d];
+ t->left = (png_byte)i;
+ t->right = (png_byte)j;
+ hash[d] = t;
+ }
+ }
+ if (t == NULL)
+ break;
+ }
+
+ if (t != NULL)
+ for (i = 0; i <= max_d; i++)
+ {
+ if (hash[i] != NULL)
+ {
+ png_dsortp p;
+
+ for (p = hash[i]; p; p = p->next)
+ {
+ if ((int)png_ptr->index_to_palette[p->left]
+ < num_new_palette &&
+ (int)png_ptr->index_to_palette[p->right]
+ < num_new_palette)
+ {
+ int j, next_j;
+
+ if (num_new_palette & 0x01)
+ {
+ j = p->left;
+ next_j = p->right;
+ }
+ else
+ {
+ j = p->right;
+ next_j = p->left;
+ }
+
+ num_new_palette--;
+ palette[png_ptr->index_to_palette[j]]
+ = palette[num_new_palette];
+ if (full_quantize == 0)
+ {
+ int k;
+
+ for (k = 0; k < num_palette; k++)
+ {
+ if (png_ptr->quantize_index[k] ==
+ png_ptr->index_to_palette[j])
+ png_ptr->quantize_index[k] =
+ png_ptr->index_to_palette[next_j];
+
+ if ((int)png_ptr->quantize_index[k] ==
+ num_new_palette)
+ png_ptr->quantize_index[k] =
+ png_ptr->index_to_palette[j];
+ }
+ }
+
+ png_ptr->index_to_palette[png_ptr->palette_to_index
+ [num_new_palette]] = png_ptr->index_to_palette[j];
+
+ png_ptr->palette_to_index[png_ptr->index_to_palette[j]]
+ = png_ptr->palette_to_index[num_new_palette];
+
+ png_ptr->index_to_palette[j] =
+ (png_byte)num_new_palette;
+
+ png_ptr->palette_to_index[num_new_palette] =
+ (png_byte)j;
+ }
+ if (num_new_palette <= maximum_colors)
+ break;
+ }
+ if (num_new_palette <= maximum_colors)
+ break;
+ }
+ }
+
+ for (i = 0; i < 769; i++)
+ {
+ if (hash[i] != NULL)
+ {
+ png_dsortp p = hash[i];
+ while (p)
+ {
+ t = p->next;
+ png_free(png_ptr, p);
+ p = t;
+ }
+ }
+ hash[i] = 0;
+ }
+ max_d += 96;
+ }
+ png_free(png_ptr, hash);
+ png_free(png_ptr, png_ptr->palette_to_index);
+ png_free(png_ptr, png_ptr->index_to_palette);
+ png_ptr->palette_to_index = NULL;
+ png_ptr->index_to_palette = NULL;
+ }
+ num_palette = maximum_colors;
+ }
+ if (png_ptr->palette == NULL)
+ {
+ png_ptr->palette = palette;
+ }
+ png_ptr->num_palette = (png_uint_16)num_palette;
+
+ if (full_quantize != 0)
+ {
+ int i;
+ png_bytep distance;
+ int total_bits = PNG_QUANTIZE_RED_BITS + PNG_QUANTIZE_GREEN_BITS +
+ PNG_QUANTIZE_BLUE_BITS;
+ int num_red = (1 << PNG_QUANTIZE_RED_BITS);
+ int num_green = (1 << PNG_QUANTIZE_GREEN_BITS);
+ int num_blue = (1 << PNG_QUANTIZE_BLUE_BITS);
+ png_size_t num_entries = ((png_size_t)1 << total_bits);
+
+ png_ptr->palette_lookup = (png_bytep)png_calloc(png_ptr,
+ (png_uint_32)(num_entries * (sizeof (png_byte))));
+
+ distance = (png_bytep)png_malloc(png_ptr, (png_uint_32)(num_entries *
+ (sizeof (png_byte))));
+
+ memset(distance, 0xff, num_entries * (sizeof (png_byte)));
+
+ for (i = 0; i < num_palette; i++)
+ {
+ int ir, ig, ib;
+ int r = (palette[i].red >> (8 - PNG_QUANTIZE_RED_BITS));
+ int g = (palette[i].green >> (8 - PNG_QUANTIZE_GREEN_BITS));
+ int b = (palette[i].blue >> (8 - PNG_QUANTIZE_BLUE_BITS));
+
+ for (ir = 0; ir < num_red; ir++)
+ {
+ /* int dr = abs(ir - r); */
+ int dr = ((ir > r) ? ir - r : r - ir);
+ int index_r = (ir << (PNG_QUANTIZE_BLUE_BITS +
+ PNG_QUANTIZE_GREEN_BITS));
+
+ for (ig = 0; ig < num_green; ig++)
+ {
+ /* int dg = abs(ig - g); */
+ int dg = ((ig > g) ? ig - g : g - ig);
+ int dt = dr + dg;
+ int dm = ((dr > dg) ? dr : dg);
+ int index_g = index_r | (ig << PNG_QUANTIZE_BLUE_BITS);
+
+ for (ib = 0; ib < num_blue; ib++)
+ {
+ int d_index = index_g | ib;
+ /* int db = abs(ib - b); */
+ int db = ((ib > b) ? ib - b : b - ib);
+ int dmax = ((dm > db) ? dm : db);
+ int d = dmax + dt + db;
+
+ if (d < (int)distance[d_index])
+ {
+ distance[d_index] = (png_byte)d;
+ png_ptr->palette_lookup[d_index] = (png_byte)i;
+ }
+ }
+ }
+ }
+ }
+
+ png_free(png_ptr, distance);
+ }
+}
+#endif /* READ_QUANTIZE */
+
+#ifdef PNG_READ_GAMMA_SUPPORTED
+void PNGFAPI
+png_set_gamma_fixed(png_structrp png_ptr, png_fixed_point scrn_gamma,
+ png_fixed_point file_gamma)
+{
+ png_debug(1, "in png_set_gamma_fixed");
+
+ if (png_rtran_ok(png_ptr, 0) == 0)
+ return;
+
+ /* New in libpng-1.5.4 - reserve particular negative values as flags. */
+ scrn_gamma = translate_gamma_flags(png_ptr, scrn_gamma, 1/*screen*/);
+ file_gamma = translate_gamma_flags(png_ptr, file_gamma, 0/*file*/);
+
+ /* Checking the gamma values for being >0 was added in 1.5.4 along with the
+ * premultiplied alpha support; this actually hides an undocumented feature
+ * of the previous implementation which allowed gamma processing to be
+ * disabled in background handling. There is no evidence (so far) that this
+ * was being used; however, png_set_background itself accepted and must still
+ * accept '0' for the gamma value it takes, because it isn't always used.
+ *
+ * Since this is an API change (albeit a very minor one that removes an
+ * undocumented API feature) the following checks were only enabled in
+ * libpng-1.6.0.
+ */
+ if (file_gamma <= 0)
+ png_error(png_ptr, "invalid file gamma in png_set_gamma");
+
+ if (scrn_gamma <= 0)
+ png_error(png_ptr, "invalid screen gamma in png_set_gamma");
+
+ /* Set the gamma values unconditionally - this overrides the value in the PNG
+ * file if a gAMA chunk was present. png_set_alpha_mode provides a
+ * different, easier, way to default the file gamma.
+ */
+ png_ptr->colorspace.gamma = file_gamma;
+ png_ptr->colorspace.flags |= PNG_COLORSPACE_HAVE_GAMMA;
+ png_ptr->screen_gamma = scrn_gamma;
+}
+
+# ifdef PNG_FLOATING_POINT_SUPPORTED
+void PNGAPI
+png_set_gamma(png_structrp png_ptr, double scrn_gamma, double file_gamma)
+{
+ png_set_gamma_fixed(png_ptr, convert_gamma_value(png_ptr, scrn_gamma),
+ convert_gamma_value(png_ptr, file_gamma));
+}
+# endif /* FLOATING_POINT */
+#endif /* READ_GAMMA */
+
+#ifdef PNG_READ_EXPAND_SUPPORTED
+/* Expand paletted images to RGB, expand grayscale images of
+ * less than 8-bit depth to 8-bit depth, and expand tRNS chunks
+ * to alpha channels.
+ */
+void PNGAPI
+png_set_expand(png_structrp png_ptr)
+{
+ png_debug(1, "in png_set_expand");
+
+ if (png_rtran_ok(png_ptr, 0) == 0)
+ return;
+
+ png_ptr->transformations |= (PNG_EXPAND | PNG_EXPAND_tRNS);
+}
+
+/* GRR 19990627: the following three functions currently are identical
+ * to png_set_expand(). However, it is entirely reasonable that someone
+ * might wish to expand an indexed image to RGB but *not* expand a single,
+ * fully transparent palette entry to a full alpha channel--perhaps instead
+ * convert tRNS to the grayscale/RGB format (16-bit RGB value), or replace
+ * the transparent color with a particular RGB value, or drop tRNS entirely.
+ * IOW, a future version of the library may make the transformations flag
+ * a bit more fine-grained, with separate bits for each of these three
+ * functions.
+ *
+ * More to the point, these functions make it obvious what libpng will be
+ * doing, whereas "expand" can (and does) mean any number of things.
+ *
+ * GRP 20060307: In libpng-1.2.9, png_set_gray_1_2_4_to_8() was modified
+ * to expand only the sample depth but not to expand the tRNS to alpha
+ * and its name was changed to png_set_expand_gray_1_2_4_to_8().
+ */
+
+/* Expand paletted images to RGB. */
+void PNGAPI
+png_set_palette_to_rgb(png_structrp png_ptr)
+{
+ png_debug(1, "in png_set_palette_to_rgb");
+
+ if (png_rtran_ok(png_ptr, 0) == 0)
+ return;
+
+ png_ptr->transformations |= (PNG_EXPAND | PNG_EXPAND_tRNS);
+}
+
+/* Expand grayscale images of less than 8-bit depth to 8 bits. */
+void PNGAPI
+png_set_expand_gray_1_2_4_to_8(png_structrp png_ptr)
+{
+ png_debug(1, "in png_set_expand_gray_1_2_4_to_8");
+
+ if (png_rtran_ok(png_ptr, 0) == 0)
+ return;
+
+ png_ptr->transformations |= PNG_EXPAND;
+}
+
+/* Expand tRNS chunks to alpha channels. */
+void PNGAPI
+png_set_tRNS_to_alpha(png_structrp png_ptr)
+{
+ png_debug(1, "in png_set_tRNS_to_alpha");
+
+ if (png_rtran_ok(png_ptr, 0) == 0)
+ return;
+
+ png_ptr->transformations |= (PNG_EXPAND | PNG_EXPAND_tRNS);
+}
+#endif /* READ_EXPAND */
+
+#ifdef PNG_READ_EXPAND_16_SUPPORTED
+/* Expand to 16-bit channels, expand the tRNS chunk too (because otherwise
+ * it may not work correctly.)
+ */
+void PNGAPI
+png_set_expand_16(png_structrp png_ptr)
+{
+ png_debug(1, "in png_set_expand_16");
+
+ if (png_rtran_ok(png_ptr, 0) == 0)
+ return;
+
+ png_ptr->transformations |= (PNG_EXPAND_16 | PNG_EXPAND | PNG_EXPAND_tRNS);
+}
+#endif
+
+#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
+void PNGAPI
+png_set_gray_to_rgb(png_structrp png_ptr)
+{
+ png_debug(1, "in png_set_gray_to_rgb");
+
+ if (png_rtran_ok(png_ptr, 0) == 0)
+ return;
+
+ /* Because rgb must be 8 bits or more: */
+ png_set_expand_gray_1_2_4_to_8(png_ptr);
+ png_ptr->transformations |= PNG_GRAY_TO_RGB;
+}
+#endif
+
+#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
+void PNGFAPI
+png_set_rgb_to_gray_fixed(png_structrp png_ptr, int error_action,
+ png_fixed_point red, png_fixed_point green)
+{
+ png_debug(1, "in png_set_rgb_to_gray");
+
+ /* Need the IHDR here because of the check on color_type below. */
+ /* TODO: fix this */
+ if (png_rtran_ok(png_ptr, 1) == 0)
+ return;
+
+ switch (error_action)
+ {
+ case PNG_ERROR_ACTION_NONE:
+ png_ptr->transformations |= PNG_RGB_TO_GRAY;
+ break;
+
+ case PNG_ERROR_ACTION_WARN:
+ png_ptr->transformations |= PNG_RGB_TO_GRAY_WARN;
+ break;
+
+ case PNG_ERROR_ACTION_ERROR:
+ png_ptr->transformations |= PNG_RGB_TO_GRAY_ERR;
+ break;
+
+ default:
+ png_error(png_ptr, "invalid error action to rgb_to_gray");
+ break;
+ }
+
+ if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
+#ifdef PNG_READ_EXPAND_SUPPORTED
+ png_ptr->transformations |= PNG_EXPAND;
+#else
+ {
+ /* Make this an error in 1.6 because otherwise the application may assume
+ * that it just worked and get a memory overwrite.
+ */
+ png_error(png_ptr,
+ "Cannot do RGB_TO_GRAY without EXPAND_SUPPORTED");
+
+ /* png_ptr->transformations &= ~PNG_RGB_TO_GRAY; */
+ }
+#endif
+ {
+ if (red >= 0 && green >= 0 && red + green <= PNG_FP_1)
+ {
+ png_uint_16 red_int, green_int;
+
+ /* NOTE: this calculation does not round, but this behavior is retained
+ * for consistency; the inaccuracy is very small. The code here always
+ * overwrites the coefficients, regardless of whether they have been
+ * defaulted or set already.
+ */
+ red_int = (png_uint_16)(((png_uint_32)red*32768)/100000);
+ green_int = (png_uint_16)(((png_uint_32)green*32768)/100000);
+
+ png_ptr->rgb_to_gray_red_coeff = red_int;
+ png_ptr->rgb_to_gray_green_coeff = green_int;
+ png_ptr->rgb_to_gray_coefficients_set = 1;
+ }
+
+ else
+ {
+ if (red >= 0 && green >= 0)
+ png_app_warning(png_ptr,
+ "ignoring out of range rgb_to_gray coefficients");
+
+ /* Use the defaults, from the cHRM chunk if set, else the historical
+ * values which are close to the sRGB/HDTV/ITU-Rec 709 values. See
+ * png_do_rgb_to_gray for more discussion of the values. In this case
+ * the coefficients are not marked as 'set' and are not overwritten if
+ * something has already provided a default.
+ */
+ if (png_ptr->rgb_to_gray_red_coeff == 0 &&
+ png_ptr->rgb_to_gray_green_coeff == 0)
+ {
+ png_ptr->rgb_to_gray_red_coeff = 6968;
+ png_ptr->rgb_to_gray_green_coeff = 23434;
+ /* png_ptr->rgb_to_gray_blue_coeff = 2366; */
+ }
+ }
+ }
+}
+
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+/* Convert a RGB image to a grayscale of the same width. This allows us,
+ * for example, to convert a 24 bpp RGB image into an 8 bpp grayscale image.
+ */
+
+void PNGAPI
+png_set_rgb_to_gray(png_structrp png_ptr, int error_action, double red,
+ double green)
+{
+ png_set_rgb_to_gray_fixed(png_ptr, error_action,
+ png_fixed(png_ptr, red, "rgb to gray red coefficient"),
+ png_fixed(png_ptr, green, "rgb to gray green coefficient"));
+}
+#endif /* FLOATING POINT */
+
+#endif /* RGB_TO_GRAY */
+
+#if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) || \
+ defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED)
+void PNGAPI
+png_set_read_user_transform_fn(png_structrp png_ptr, png_user_transform_ptr
+ read_user_transform_fn)
+{
+ png_debug(1, "in png_set_read_user_transform_fn");
+
+#ifdef PNG_READ_USER_TRANSFORM_SUPPORTED
+ png_ptr->transformations |= PNG_USER_TRANSFORM;
+ png_ptr->read_user_transform_fn = read_user_transform_fn;
+#endif
+}
+#endif
+
+#ifdef PNG_READ_TRANSFORMS_SUPPORTED
+#ifdef PNG_READ_GAMMA_SUPPORTED
+/* In the case of gamma transformations only do transformations on images where
+ * the [file] gamma and screen_gamma are not close reciprocals, otherwise it
+ * slows things down slightly, and also needlessly introduces small errors.
+ */
+static int /* PRIVATE */
+png_gamma_threshold(png_fixed_point screen_gamma, png_fixed_point file_gamma)
+{
+ /* PNG_GAMMA_THRESHOLD is the threshold for performing gamma
+ * correction as a difference of the overall transform from 1.0
+ *
+ * We want to compare the threshold with s*f - 1, if we get
+ * overflow here it is because of wacky gamma values so we
+ * turn on processing anyway.
+ */
+ png_fixed_point gtest;
+ return !png_muldiv(>est, screen_gamma, file_gamma, PNG_FP_1) ||
+ png_gamma_significant(gtest);
+}
+#endif
+
+/* Initialize everything needed for the read. This includes modifying
+ * the palette.
+ */
+
+/* For the moment 'png_init_palette_transformations' and
+ * 'png_init_rgb_transformations' only do some flag canceling optimizations.
+ * The intent is that these two routines should have palette or rgb operations
+ * extracted from 'png_init_read_transformations'.
+ */
+static void /* PRIVATE */
+png_init_palette_transformations(png_structrp png_ptr)
+{
+ /* Called to handle the (input) palette case. In png_do_read_transformations
+ * the first step is to expand the palette if requested, so this code must
+ * take care to only make changes that are invariant with respect to the
+ * palette expansion, or only do them if there is no expansion.
+ *
+ * STRIP_ALPHA has already been handled in the caller (by setting num_trans
+ * to 0.)
+ */
+ int input_has_alpha = 0;
+ int input_has_transparency = 0;
+
+ if (png_ptr->num_trans > 0)
+ {
+ int i;
+
+ /* Ignore if all the entries are opaque (unlikely!) */
+ for (i=0; i<png_ptr->num_trans; ++i)
+ {
+ if (png_ptr->trans_alpha[i] == 255)
+ continue;
+ else if (png_ptr->trans_alpha[i] == 0)
+ input_has_transparency = 1;
+ else
+ {
+ input_has_transparency = 1;
+ input_has_alpha = 1;
+ break;
+ }
+ }
+ }
+
+ /* If no alpha we can optimize. */
+ if (input_has_alpha == 0)
+ {
+ /* Any alpha means background and associative alpha processing is
+ * required, however if the alpha is 0 or 1 throughout OPTIMIZE_ALPHA
+ * and ENCODE_ALPHA are irrelevant.
+ */
+ png_ptr->transformations &= ~PNG_ENCODE_ALPHA;
+ png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA;
+
+ if (input_has_transparency == 0)
+ png_ptr->transformations &= ~(PNG_COMPOSE | PNG_BACKGROUND_EXPAND);
+ }
+
+#if defined(PNG_READ_EXPAND_SUPPORTED) && defined(PNG_READ_BACKGROUND_SUPPORTED)
+ /* png_set_background handling - deals with the complexity of whether the
+ * background color is in the file format or the screen format in the case
+ * where an 'expand' will happen.
+ */
+
+ /* The following code cannot be entered in the alpha pre-multiplication case
+ * because PNG_BACKGROUND_EXPAND is cancelled below.
+ */
+ if ((png_ptr->transformations & PNG_BACKGROUND_EXPAND) != 0 &&
+ (png_ptr->transformations & PNG_EXPAND) != 0)
+ {
+ {
+ png_ptr->background.red =
+ png_ptr->palette[png_ptr->background.index].red;
+ png_ptr->background.green =
+ png_ptr->palette[png_ptr->background.index].green;
+ png_ptr->background.blue =
+ png_ptr->palette[png_ptr->background.index].blue;
+
+#ifdef PNG_READ_INVERT_ALPHA_SUPPORTED
+ if ((png_ptr->transformations & PNG_INVERT_ALPHA) != 0)
+ {
+ if ((png_ptr->transformations & PNG_EXPAND_tRNS) == 0)
+ {
+ /* Invert the alpha channel (in tRNS) unless the pixels are
+ * going to be expanded, in which case leave it for later
+ */
+ int i, istop = png_ptr->num_trans;
+
+ for (i=0; i<istop; i++)
+ png_ptr->trans_alpha[i] = (png_byte)(255 -
+ png_ptr->trans_alpha[i]);
+ }
+ }
+#endif /* READ_INVERT_ALPHA */
+ }
+ } /* background expand and (therefore) no alpha association. */
+#endif /* READ_EXPAND && READ_BACKGROUND */
+}
+
+static void /* PRIVATE */
+png_init_rgb_transformations(png_structrp png_ptr)
+{
+ /* Added to libpng-1.5.4: check the color type to determine whether there
+ * is any alpha or transparency in the image and simply cancel the
+ * background and alpha mode stuff if there isn't.
+ */
+ int input_has_alpha = (png_ptr->color_type & PNG_COLOR_MASK_ALPHA) != 0;
+ int input_has_transparency = png_ptr->num_trans > 0;
+
+ /* If no alpha we can optimize. */
+ if (input_has_alpha == 0)
+ {
+ /* Any alpha means background and associative alpha processing is
+ * required, however if the alpha is 0 or 1 throughout OPTIMIZE_ALPHA
+ * and ENCODE_ALPHA are irrelevant.
+ */
+# ifdef PNG_READ_ALPHA_MODE_SUPPORTED
+ png_ptr->transformations &= ~PNG_ENCODE_ALPHA;
+ png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA;
+# endif
+
+ if (input_has_transparency == 0)
+ png_ptr->transformations &= ~(PNG_COMPOSE | PNG_BACKGROUND_EXPAND);
+ }
+
+#if defined(PNG_READ_EXPAND_SUPPORTED) && defined(PNG_READ_BACKGROUND_SUPPORTED)
+ /* png_set_background handling - deals with the complexity of whether the
+ * background color is in the file format or the screen format in the case
+ * where an 'expand' will happen.
+ */
+
+ /* The following code cannot be entered in the alpha pre-multiplication case
+ * because PNG_BACKGROUND_EXPAND is cancelled below.
+ */
+ if ((png_ptr->transformations & PNG_BACKGROUND_EXPAND) != 0 &&
+ (png_ptr->transformations & PNG_EXPAND) != 0 &&
+ (png_ptr->color_type & PNG_COLOR_MASK_COLOR) == 0)
+ /* i.e., GRAY or GRAY_ALPHA */
+ {
+ {
+ /* Expand background and tRNS chunks */
+ int gray = png_ptr->background.gray;
+ int trans_gray = png_ptr->trans_color.gray;
+
+ switch (png_ptr->bit_depth)
+ {
+ case 1:
+ gray *= 0xff;
+ trans_gray *= 0xff;
+ break;
+
+ case 2:
+ gray *= 0x55;
+ trans_gray *= 0x55;
+ break;
+
+ case 4:
+ gray *= 0x11;
+ trans_gray *= 0x11;
+ break;
+
+ default:
+
+ case 8:
+ /* FALL THROUGH (Already 8 bits) */
+
+ case 16:
+ /* Already a full 16 bits */
+ break;
+ }
+
+ png_ptr->background.red = png_ptr->background.green =
+ png_ptr->background.blue = (png_uint_16)gray;
+
+ if ((png_ptr->transformations & PNG_EXPAND_tRNS) == 0)
+ {
+ png_ptr->trans_color.red = png_ptr->trans_color.green =
+ png_ptr->trans_color.blue = (png_uint_16)trans_gray;
+ }
+ }
+ } /* background expand and (therefore) no alpha association. */
+#endif /* READ_EXPAND && READ_BACKGROUND */
+}
+
+void /* PRIVATE */
+png_init_read_transformations(png_structrp png_ptr)
+{
+ png_debug(1, "in png_init_read_transformations");
+
+ /* This internal function is called from png_read_start_row in pngrutil.c
+ * and it is called before the 'rowbytes' calculation is done, so the code
+ * in here can change or update the transformations flags.
+ *
+ * First do updates that do not depend on the details of the PNG image data
+ * being processed.
+ */
+
+#ifdef PNG_READ_GAMMA_SUPPORTED
+ /* Prior to 1.5.4 these tests were performed from png_set_gamma, 1.5.4 adds
+ * png_set_alpha_mode and this is another source for a default file gamma so
+ * the test needs to be performed later - here. In addition prior to 1.5.4
+ * the tests were repeated for the PALETTE color type here - this is no
+ * longer necessary (and doesn't seem to have been necessary before.)
+ */
+ {
+ /* The following temporary indicates if overall gamma correction is
+ * required.
+ */
+ int gamma_correction = 0;
+
+ if (png_ptr->colorspace.gamma != 0) /* has been set */
+ {
+ if (png_ptr->screen_gamma != 0) /* screen set too */
+ gamma_correction = png_gamma_threshold(png_ptr->colorspace.gamma,
+ png_ptr->screen_gamma);
+
+ else
+ /* Assume the output matches the input; a long time default behavior
+ * of libpng, although the standard has nothing to say about this.
+ */
+ png_ptr->screen_gamma = png_reciprocal(png_ptr->colorspace.gamma);
+ }
+
+ else if (png_ptr->screen_gamma != 0)
+ /* The converse - assume the file matches the screen, note that this
+ * perhaps undesireable default can (from 1.5.4) be changed by calling
+ * png_set_alpha_mode (even if the alpha handling mode isn't required
+ * or isn't changed from the default.)
+ */
+ png_ptr->colorspace.gamma = png_reciprocal(png_ptr->screen_gamma);
+
+ else /* neither are set */
+ /* Just in case the following prevents any processing - file and screen
+ * are both assumed to be linear and there is no way to introduce a
+ * third gamma value other than png_set_background with 'UNIQUE', and,
+ * prior to 1.5.4
+ */
+ png_ptr->screen_gamma = png_ptr->colorspace.gamma = PNG_FP_1;
+
+ /* We have a gamma value now. */
+ png_ptr->colorspace.flags |= PNG_COLORSPACE_HAVE_GAMMA;
+
+ /* Now turn the gamma transformation on or off as appropriate. Notice
+ * that PNG_GAMMA just refers to the file->screen correction. Alpha
+ * composition may independently cause gamma correction because it needs
+ * linear data (e.g. if the file has a gAMA chunk but the screen gamma
+ * hasn't been specified.) In any case this flag may get turned off in
+ * the code immediately below if the transform can be handled outside the
+ * row loop.
+ */
+ if (gamma_correction != 0)
+ png_ptr->transformations |= PNG_GAMMA;
+
+ else
+ png_ptr->transformations &= ~PNG_GAMMA;
+ }
+#endif
+
+ /* Certain transformations have the effect of preventing other
+ * transformations that happen afterward in png_do_read_transformations;
+ * resolve the interdependencies here. From the code of
+ * png_do_read_transformations the order is:
+ *
+ * 1) PNG_EXPAND (including PNG_EXPAND_tRNS)
+ * 2) PNG_STRIP_ALPHA (if no compose)
+ * 3) PNG_RGB_TO_GRAY
+ * 4) PNG_GRAY_TO_RGB iff !PNG_BACKGROUND_IS_GRAY
+ * 5) PNG_COMPOSE
+ * 6) PNG_GAMMA
+ * 7) PNG_STRIP_ALPHA (if compose)
+ * 8) PNG_ENCODE_ALPHA
+ * 9) PNG_SCALE_16_TO_8
+ * 10) PNG_16_TO_8
+ * 11) PNG_QUANTIZE (converts to palette)
+ * 12) PNG_EXPAND_16
+ * 13) PNG_GRAY_TO_RGB iff PNG_BACKGROUND_IS_GRAY
+ * 14) PNG_INVERT_MONO
+ * 15) PNG_INVERT_ALPHA
+ * 16) PNG_SHIFT
+ * 17) PNG_PACK
+ * 18) PNG_BGR
+ * 19) PNG_PACKSWAP
+ * 20) PNG_FILLER (includes PNG_ADD_ALPHA)
+ * 21) PNG_SWAP_ALPHA
+ * 22) PNG_SWAP_BYTES
+ * 23) PNG_USER_TRANSFORM [must be last]
+ */
+#ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
+ if ((png_ptr->transformations & PNG_STRIP_ALPHA) != 0 &&
+ (png_ptr->transformations & PNG_COMPOSE) == 0)
+ {
+ /* Stripping the alpha channel happens immediately after the 'expand'
+ * transformations, before all other transformation, so it cancels out
+ * the alpha handling. It has the side effect negating the effect of
+ * PNG_EXPAND_tRNS too:
+ */
+ png_ptr->transformations &= ~(PNG_BACKGROUND_EXPAND | PNG_ENCODE_ALPHA |
+ PNG_EXPAND_tRNS);
+ png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA;
+
+ /* Kill the tRNS chunk itself too. Prior to 1.5.4 this did not happen
+ * so transparency information would remain just so long as it wasn't
+ * expanded. This produces unexpected API changes if the set of things
+ * that do PNG_EXPAND_tRNS changes (perfectly possible given the
+ * documentation - which says ask for what you want, accept what you
+ * get.) This makes the behavior consistent from 1.5.4:
+ */
+ png_ptr->num_trans = 0;
+ }
+#endif /* STRIP_ALPHA supported, no COMPOSE */
+
+#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
+ /* If the screen gamma is about 1.0 then the OPTIMIZE_ALPHA and ENCODE_ALPHA
+ * settings will have no effect.
+ */
+ if (png_gamma_significant(png_ptr->screen_gamma) == 0)
+ {
+ png_ptr->transformations &= ~PNG_ENCODE_ALPHA;
+ png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA;
+ }
+#endif
+
+#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
+ /* Make sure the coefficients for the rgb to gray conversion are set
+ * appropriately.
+ */
+ if ((png_ptr->transformations & PNG_RGB_TO_GRAY) != 0)
+ png_colorspace_set_rgb_coefficients(png_ptr);
+#endif
+
+#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
+#if defined(PNG_READ_EXPAND_SUPPORTED) && defined(PNG_READ_BACKGROUND_SUPPORTED)
+ /* Detect gray background and attempt to enable optimization for
+ * gray --> RGB case.
+ *
+ * Note: if PNG_BACKGROUND_EXPAND is set and color_type is either RGB or
+ * RGB_ALPHA (in which case need_expand is superfluous anyway), the
+ * background color might actually be gray yet not be flagged as such.
+ * This is not a problem for the current code, which uses
+ * PNG_BACKGROUND_IS_GRAY only to decide when to do the
+ * png_do_gray_to_rgb() transformation.
+ *
+ * TODO: this code needs to be revised to avoid the complexity and
+ * interdependencies. The color type of the background should be recorded in
+ * png_set_background, along with the bit depth, then the code has a record
+ * of exactly what color space the background is currently in.
+ */
+ if ((png_ptr->transformations & PNG_BACKGROUND_EXPAND) != 0)
+ {
+ /* PNG_BACKGROUND_EXPAND: the background is in the file color space, so if
+ * the file was grayscale the background value is gray.
+ */
+ if ((png_ptr->color_type & PNG_COLOR_MASK_COLOR) == 0)
+ png_ptr->mode |= PNG_BACKGROUND_IS_GRAY;
+ }
+
+ else if ((png_ptr->transformations & PNG_COMPOSE) != 0)
+ {
+ /* PNG_COMPOSE: png_set_background was called with need_expand false,
+ * so the color is in the color space of the output or png_set_alpha_mode
+ * was called and the color is black. Ignore RGB_TO_GRAY because that
+ * happens before GRAY_TO_RGB.
+ */
+ if ((png_ptr->transformations & PNG_GRAY_TO_RGB) != 0)
+ {
+ if (png_ptr->background.red == png_ptr->background.green &&
+ png_ptr->background.red == png_ptr->background.blue)
+ {
+ png_ptr->mode |= PNG_BACKGROUND_IS_GRAY;
+ png_ptr->background.gray = png_ptr->background.red;
+ }
+ }
+ }
+#endif /* READ_EXPAND && READ_BACKGROUND */
+#endif /* READ_GRAY_TO_RGB */
+
+ /* For indexed PNG data (PNG_COLOR_TYPE_PALETTE) many of the transformations
+ * can be performed directly on the palette, and some (such as rgb to gray)
+ * can be optimized inside the palette. This is particularly true of the
+ * composite (background and alpha) stuff, which can be pretty much all done
+ * in the palette even if the result is expanded to RGB or gray afterward.
+ *
+ * NOTE: this is Not Yet Implemented, the code behaves as in 1.5.1 and
+ * earlier and the palette stuff is actually handled on the first row. This
+ * leads to the reported bug that the palette returned by png_get_PLTE is not
+ * updated.
+ */
+ if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
+ png_init_palette_transformations(png_ptr);
+
+ else
+ png_init_rgb_transformations(png_ptr);
+
+#if defined(PNG_READ_BACKGROUND_SUPPORTED) && \
+ defined(PNG_READ_EXPAND_16_SUPPORTED)
+ if ((png_ptr->transformations & PNG_EXPAND_16) != 0 &&
+ (png_ptr->transformations & PNG_COMPOSE) != 0 &&
+ (png_ptr->transformations & PNG_BACKGROUND_EXPAND) == 0 &&
+ png_ptr->bit_depth != 16)
+ {
+ /* TODO: fix this. Because the expand_16 operation is after the compose
+ * handling the background color must be 8, not 16, bits deep, but the
+ * application will supply a 16-bit value so reduce it here.
+ *
+ * The PNG_BACKGROUND_EXPAND code above does not expand to 16 bits at
+ * present, so that case is ok (until do_expand_16 is moved.)
+ *
+ * NOTE: this discards the low 16 bits of the user supplied background
+ * color, but until expand_16 works properly there is no choice!
+ */
+# define CHOP(x) (x)=((png_uint_16)PNG_DIV257(x))
+ CHOP(png_ptr->background.red);
+ CHOP(png_ptr->background.green);
+ CHOP(png_ptr->background.blue);
+ CHOP(png_ptr->background.gray);
+# undef CHOP
+ }
+#endif /* READ_BACKGROUND && READ_EXPAND_16 */
+
+#if defined(PNG_READ_BACKGROUND_SUPPORTED) && \
+ (defined(PNG_READ_SCALE_16_TO_8_SUPPORTED) || \
+ defined(PNG_READ_STRIP_16_TO_8_SUPPORTED))
+ if ((png_ptr->transformations & (PNG_16_TO_8|PNG_SCALE_16_TO_8)) != 0 &&
+ (png_ptr->transformations & PNG_COMPOSE) != 0 &&
+ (png_ptr->transformations & PNG_BACKGROUND_EXPAND) == 0 &&
+ png_ptr->bit_depth == 16)
+ {
+ /* On the other hand, if a 16-bit file is to be reduced to 8-bits per
+ * component this will also happen after PNG_COMPOSE and so the background
+ * color must be pre-expanded here.
+ *
+ * TODO: fix this too.
+ */
+ png_ptr->background.red = (png_uint_16)(png_ptr->background.red * 257);
+ png_ptr->background.green =
+ (png_uint_16)(png_ptr->background.green * 257);
+ png_ptr->background.blue = (png_uint_16)(png_ptr->background.blue * 257);
+ png_ptr->background.gray = (png_uint_16)(png_ptr->background.gray * 257);
+ }
+#endif
+
+ /* NOTE: below 'PNG_READ_ALPHA_MODE_SUPPORTED' is presumed to also enable the
+ * background support (see the comments in scripts/pnglibconf.dfa), this
+ * allows pre-multiplication of the alpha channel to be implemented as
+ * compositing on black. This is probably sub-optimal and has been done in
+ * 1.5.4 betas simply to enable external critique and testing (i.e. to
+ * implement the new API quickly, without lots of internal changes.)
+ */
+
+#ifdef PNG_READ_GAMMA_SUPPORTED
+# ifdef PNG_READ_BACKGROUND_SUPPORTED
+ /* Includes ALPHA_MODE */
+ png_ptr->background_1 = png_ptr->background;
+# endif
+
+ /* This needs to change - in the palette image case a whole set of tables are
+ * built when it would be quicker to just calculate the correct value for
+ * each palette entry directly. Also, the test is too tricky - why check
+ * PNG_RGB_TO_GRAY if PNG_GAMMA is not set? The answer seems to be that
+ * PNG_GAMMA is cancelled even if the gamma is known? The test excludes the
+ * PNG_COMPOSE case, so apparently if there is no *overall* gamma correction
+ * the gamma tables will not be built even if composition is required on a
+ * gamma encoded value.
+ *
+ * In 1.5.4 this is addressed below by an additional check on the individual
+ * file gamma - if it is not 1.0 both RGB_TO_GRAY and COMPOSE need the
+ * tables.
+ */
+ if ((png_ptr->transformations & PNG_GAMMA) != 0 ||
+ ((png_ptr->transformations & PNG_RGB_TO_GRAY) != 0 &&
+ (png_gamma_significant(png_ptr->colorspace.gamma) != 0 ||
+ png_gamma_significant(png_ptr->screen_gamma) != 0)) ||
+ ((png_ptr->transformations & PNG_COMPOSE) != 0 &&
+ (png_gamma_significant(png_ptr->colorspace.gamma) != 0 ||
+ png_gamma_significant(png_ptr->screen_gamma) != 0
+# ifdef PNG_READ_BACKGROUND_SUPPORTED
+ || (png_ptr->background_gamma_type == PNG_BACKGROUND_GAMMA_UNIQUE &&
+ png_gamma_significant(png_ptr->background_gamma) != 0)
+# endif
+ )) || ((png_ptr->transformations & PNG_ENCODE_ALPHA) != 0 &&
+ png_gamma_significant(png_ptr->screen_gamma) != 0))
+ {
+ png_build_gamma_table(png_ptr, png_ptr->bit_depth);
+
+#ifdef PNG_READ_BACKGROUND_SUPPORTED
+ if ((png_ptr->transformations & PNG_COMPOSE) != 0)
+ {
+ /* Issue a warning about this combination: because RGB_TO_GRAY is
+ * optimized to do the gamma transform if present yet do_background has
+ * to do the same thing if both options are set a
+ * double-gamma-correction happens. This is true in all versions of
+ * libpng to date.
+ */
+ if ((png_ptr->transformations & PNG_RGB_TO_GRAY) != 0)
+ png_warning(png_ptr,
+ "libpng does not support gamma+background+rgb_to_gray");
+
+ if ((png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) != 0)
+ {
+ /* We don't get to here unless there is a tRNS chunk with non-opaque
+ * entries - see the checking code at the start of this function.
+ */
+ png_color back, back_1;
+ png_colorp palette = png_ptr->palette;
+ int num_palette = png_ptr->num_palette;
+ int i;
+ if (png_ptr->background_gamma_type == PNG_BACKGROUND_GAMMA_FILE)
+ {
+
+ back.red = png_ptr->gamma_table[png_ptr->background.red];
+ back.green = png_ptr->gamma_table[png_ptr->background.green];
+ back.blue = png_ptr->gamma_table[png_ptr->background.blue];
+
+ back_1.red = png_ptr->gamma_to_1[png_ptr->background.red];
+ back_1.green = png_ptr->gamma_to_1[png_ptr->background.green];
+ back_1.blue = png_ptr->gamma_to_1[png_ptr->background.blue];
+ }
+ else
+ {
+ png_fixed_point g, gs;
+
+ switch (png_ptr->background_gamma_type)
+ {
+ case PNG_BACKGROUND_GAMMA_SCREEN:
+ g = (png_ptr->screen_gamma);
+ gs = PNG_FP_1;
+ break;
+
+ case PNG_BACKGROUND_GAMMA_FILE:
+ g = png_reciprocal(png_ptr->colorspace.gamma);
+ gs = png_reciprocal2(png_ptr->colorspace.gamma,
+ png_ptr->screen_gamma);
+ break;
+
+ case PNG_BACKGROUND_GAMMA_UNIQUE:
+ g = png_reciprocal(png_ptr->background_gamma);
+ gs = png_reciprocal2(png_ptr->background_gamma,
+ png_ptr->screen_gamma);
+ break;
+ default:
+ g = PNG_FP_1; /* back_1 */
+ gs = PNG_FP_1; /* back */
+ break;
+ }
+
+ if (png_gamma_significant(gs) != 0)
+ {
+ back.red = png_gamma_8bit_correct(png_ptr->background.red,
+ gs);
+ back.green = png_gamma_8bit_correct(png_ptr->background.green,
+ gs);
+ back.blue = png_gamma_8bit_correct(png_ptr->background.blue,
+ gs);
+ }
+
+ else
+ {
+ back.red = (png_byte)png_ptr->background.red;
+ back.green = (png_byte)png_ptr->background.green;
+ back.blue = (png_byte)png_ptr->background.blue;
+ }
+
+ if (png_gamma_significant(g) != 0)
+ {
+ back_1.red = png_gamma_8bit_correct(png_ptr->background.red,
+ g);
+ back_1.green = png_gamma_8bit_correct(
+ png_ptr->background.green, g);
+ back_1.blue = png_gamma_8bit_correct(png_ptr->background.blue,
+ g);
+ }
+
+ else
+ {
+ back_1.red = (png_byte)png_ptr->background.red;
+ back_1.green = (png_byte)png_ptr->background.green;
+ back_1.blue = (png_byte)png_ptr->background.blue;
+ }
+ }
+
+ for (i = 0; i < num_palette; i++)
+ {
+ if (i < (int)png_ptr->num_trans &&
+ png_ptr->trans_alpha[i] != 0xff)
+ {
+ if (png_ptr->trans_alpha[i] == 0)
+ {
+ palette[i] = back;
+ }
+ else /* if (png_ptr->trans_alpha[i] != 0xff) */
+ {
+ png_byte v, w;
+
+ v = png_ptr->gamma_to_1[palette[i].red];
+ png_composite(w, v, png_ptr->trans_alpha[i], back_1.red);
+ palette[i].red = png_ptr->gamma_from_1[w];
+
+ v = png_ptr->gamma_to_1[palette[i].green];
+ png_composite(w, v, png_ptr->trans_alpha[i], back_1.green);
+ palette[i].green = png_ptr->gamma_from_1[w];
+
+ v = png_ptr->gamma_to_1[palette[i].blue];
+ png_composite(w, v, png_ptr->trans_alpha[i], back_1.blue);
+ palette[i].blue = png_ptr->gamma_from_1[w];
+ }
+ }
+ else
+ {
+ palette[i].red = png_ptr->gamma_table[palette[i].red];
+ palette[i].green = png_ptr->gamma_table[palette[i].green];
+ palette[i].blue = png_ptr->gamma_table[palette[i].blue];
+ }
+ }
+
+ /* Prevent the transformations being done again.
+ *
+ * NOTE: this is highly dubious; it removes the transformations in
+ * place. This seems inconsistent with the general treatment of the
+ * transformations elsewhere.
+ */
+ png_ptr->transformations &= ~(PNG_COMPOSE | PNG_GAMMA);
+ } /* color_type == PNG_COLOR_TYPE_PALETTE */
+
+ /* if (png_ptr->background_gamma_type!=PNG_BACKGROUND_GAMMA_UNKNOWN) */
+ else /* color_type != PNG_COLOR_TYPE_PALETTE */
+ {
+ int gs_sig, g_sig;
+ png_fixed_point g = PNG_FP_1; /* Correction to linear */
+ png_fixed_point gs = PNG_FP_1; /* Correction to screen */
+
+ switch (png_ptr->background_gamma_type)
+ {
+ case PNG_BACKGROUND_GAMMA_SCREEN:
+ g = png_ptr->screen_gamma;
+ /* gs = PNG_FP_1; */
+ break;
+
+ case PNG_BACKGROUND_GAMMA_FILE:
+ g = png_reciprocal(png_ptr->colorspace.gamma);
+ gs = png_reciprocal2(png_ptr->colorspace.gamma,
+ png_ptr->screen_gamma);
+ break;
+
+ case PNG_BACKGROUND_GAMMA_UNIQUE:
+ g = png_reciprocal(png_ptr->background_gamma);
+ gs = png_reciprocal2(png_ptr->background_gamma,
+ png_ptr->screen_gamma);
+ break;
+
+ default:
+ png_error(png_ptr, "invalid background gamma type");
+ }
+
+ g_sig = png_gamma_significant(g);
+ gs_sig = png_gamma_significant(gs);
+
+ if (g_sig != 0)
+ png_ptr->background_1.gray = png_gamma_correct(png_ptr,
+ png_ptr->background.gray, g);
+
+ if (gs_sig != 0)
+ png_ptr->background.gray = png_gamma_correct(png_ptr,
+ png_ptr->background.gray, gs);
+
+ if ((png_ptr->background.red != png_ptr->background.green) ||
+ (png_ptr->background.red != png_ptr->background.blue) ||
+ (png_ptr->background.red != png_ptr->background.gray))
+ {
+ /* RGB or RGBA with color background */
+ if (g_sig != 0)
+ {
+ png_ptr->background_1.red = png_gamma_correct(png_ptr,
+ png_ptr->background.red, g);
+
+ png_ptr->background_1.green = png_gamma_correct(png_ptr,
+ png_ptr->background.green, g);
+
+ png_ptr->background_1.blue = png_gamma_correct(png_ptr,
+ png_ptr->background.blue, g);
+ }
+
+ if (gs_sig != 0)
+ {
+ png_ptr->background.red = png_gamma_correct(png_ptr,
+ png_ptr->background.red, gs);
+
+ png_ptr->background.green = png_gamma_correct(png_ptr,
+ png_ptr->background.green, gs);
+
+ png_ptr->background.blue = png_gamma_correct(png_ptr,
+ png_ptr->background.blue, gs);
+ }
+ }
+
+ else
+ {
+ /* GRAY, GRAY ALPHA, RGB, or RGBA with gray background */
+ png_ptr->background_1.red = png_ptr->background_1.green
+ = png_ptr->background_1.blue = png_ptr->background_1.gray;
+
+ png_ptr->background.red = png_ptr->background.green
+ = png_ptr->background.blue = png_ptr->background.gray;
+ }
+
+ /* The background is now in screen gamma: */
+ png_ptr->background_gamma_type = PNG_BACKGROUND_GAMMA_SCREEN;
+ } /* color_type != PNG_COLOR_TYPE_PALETTE */
+ }/* png_ptr->transformations & PNG_BACKGROUND */
+
+ else
+ /* Transformation does not include PNG_BACKGROUND */
+#endif /* READ_BACKGROUND */
+ if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE
+#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
+ /* RGB_TO_GRAY needs to have non-gamma-corrected values! */
+ && ((png_ptr->transformations & PNG_EXPAND) == 0 ||
+ (png_ptr->transformations & PNG_RGB_TO_GRAY) == 0)
+#endif
+ )
+ {
+ png_colorp palette = png_ptr->palette;
+ int num_palette = png_ptr->num_palette;
+ int i;
+
+ /* NOTE: there are other transformations that should probably be in
+ * here too.
+ */
+ for (i = 0; i < num_palette; i++)
+ {
+ palette[i].red = png_ptr->gamma_table[palette[i].red];
+ palette[i].green = png_ptr->gamma_table[palette[i].green];
+ palette[i].blue = png_ptr->gamma_table[palette[i].blue];
+ }
+
+ /* Done the gamma correction. */
+ png_ptr->transformations &= ~PNG_GAMMA;
+ } /* color_type == PALETTE && !PNG_BACKGROUND transformation */
+ }
+#ifdef PNG_READ_BACKGROUND_SUPPORTED
+ else
+#endif
+#endif /* READ_GAMMA */
+
+#ifdef PNG_READ_BACKGROUND_SUPPORTED
+ /* No GAMMA transformation (see the hanging else 4 lines above) */
+ if ((png_ptr->transformations & PNG_COMPOSE) != 0 &&
+ (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE))
+ {
+ int i;
+ int istop = (int)png_ptr->num_trans;
+ png_color back;
+ png_colorp palette = png_ptr->palette;
+
+ back.red = (png_byte)png_ptr->background.red;
+ back.green = (png_byte)png_ptr->background.green;
+ back.blue = (png_byte)png_ptr->background.blue;
+
+ for (i = 0; i < istop; i++)
+ {
+ if (png_ptr->trans_alpha[i] == 0)
+ {
+ palette[i] = back;
+ }
+
+ else if (png_ptr->trans_alpha[i] != 0xff)
+ {
+ /* The png_composite() macro is defined in png.h */
+ png_composite(palette[i].red, palette[i].red,
+ png_ptr->trans_alpha[i], back.red);
+
+ png_composite(palette[i].green, palette[i].green,
+ png_ptr->trans_alpha[i], back.green);
+
+ png_composite(palette[i].blue, palette[i].blue,
+ png_ptr->trans_alpha[i], back.blue);
+ }
+ }
+
+ png_ptr->transformations &= ~PNG_COMPOSE;
+ }
+#endif /* READ_BACKGROUND */
+
+#ifdef PNG_READ_SHIFT_SUPPORTED
+ if ((png_ptr->transformations & PNG_SHIFT) != 0 &&
+ (png_ptr->transformations & PNG_EXPAND) == 0 &&
+ (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE))
+ {
+ int i;
+ int istop = png_ptr->num_palette;
+ int shift = 8 - png_ptr->sig_bit.red;
+
+ png_ptr->transformations &= ~PNG_SHIFT;
+
+ /* significant bits can be in the range 1 to 7 for a meaninful result, if
+ * the number of significant bits is 0 then no shift is done (this is an
+ * error condition which is silently ignored.)
+ */
+ if (shift > 0 && shift < 8)
+ for (i=0; i<istop; ++i)
+ {
+ int component = png_ptr->palette[i].red;
+
+ component >>= shift;
+ png_ptr->palette[i].red = (png_byte)component;
+ }
+
+ shift = 8 - png_ptr->sig_bit.green;
+ if (shift > 0 && shift < 8)
+ for (i=0; i<istop; ++i)
+ {
+ int component = png_ptr->palette[i].green;
+
+ component >>= shift;
+ png_ptr->palette[i].green = (png_byte)component;
+ }
+
+ shift = 8 - png_ptr->sig_bit.blue;
+ if (shift > 0 && shift < 8)
+ for (i=0; i<istop; ++i)
+ {
+ int component = png_ptr->palette[i].blue;
+
+ component >>= shift;
+ png_ptr->palette[i].blue = (png_byte)component;
+ }
+ }
+#endif /* READ_SHIFT */
+}
+
+/* Modify the info structure to reflect the transformations. The
+ * info should be updated so a PNG file could be written with it,
+ * assuming the transformations result in valid PNG data.
+ */
+void /* PRIVATE */
+png_read_transform_info(png_structrp png_ptr, png_inforp info_ptr)
+{
+ png_debug(1, "in png_read_transform_info");
+
+#ifdef PNG_READ_EXPAND_SUPPORTED
+ if ((png_ptr->transformations & PNG_EXPAND) != 0)
+ {
+ if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
+ {
+ /* This check must match what actually happens in
+ * png_do_expand_palette; if it ever checks the tRNS chunk to see if
+ * it is all opaque we must do the same (at present it does not.)
+ */
+ if (png_ptr->num_trans > 0)
+ info_ptr->color_type = PNG_COLOR_TYPE_RGB_ALPHA;
+
+ else
+ info_ptr->color_type = PNG_COLOR_TYPE_RGB;
+
+ info_ptr->bit_depth = 8;
+ info_ptr->num_trans = 0;
+
+ if (png_ptr->palette == NULL)
+ png_error (png_ptr, "Palette is NULL in indexed image");
+ }
+ else
+ {
+ if (png_ptr->num_trans != 0)
+ {
+ if ((png_ptr->transformations & PNG_EXPAND_tRNS) != 0)
+ info_ptr->color_type |= PNG_COLOR_MASK_ALPHA;
+ }
+ if (info_ptr->bit_depth < 8)
+ info_ptr->bit_depth = 8;
+
+ info_ptr->num_trans = 0;
+ }
+ }
+#endif
+
+#if defined(PNG_READ_BACKGROUND_SUPPORTED) ||\
+ defined(PNG_READ_ALPHA_MODE_SUPPORTED)
+ /* The following is almost certainly wrong unless the background value is in
+ * the screen space!
+ */
+ if ((png_ptr->transformations & PNG_COMPOSE) != 0)
+ info_ptr->background = png_ptr->background;
+#endif
+
+#ifdef PNG_READ_GAMMA_SUPPORTED
+ /* The following used to be conditional on PNG_GAMMA (prior to 1.5.4),
+ * however it seems that the code in png_init_read_transformations, which has
+ * been called before this from png_read_update_info->png_read_start_row
+ * sometimes does the gamma transform and cancels the flag.
+ *
+ * TODO: this looks wrong; the info_ptr should end up with a gamma equal to
+ * the screen_gamma value. The following probably results in weirdness if
+ * the info_ptr is used by the app after the rows have been read.
+ */
+ info_ptr->colorspace.gamma = png_ptr->colorspace.gamma;
+#endif
+
+ if (info_ptr->bit_depth == 16)
+ {
+# ifdef PNG_READ_16BIT_SUPPORTED
+# ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
+ if ((png_ptr->transformations & PNG_SCALE_16_TO_8) != 0)
+ info_ptr->bit_depth = 8;
+# endif
+
+# ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
+ if ((png_ptr->transformations & PNG_16_TO_8) != 0)
+ info_ptr->bit_depth = 8;
+# endif
+
+# else
+ /* No 16 bit support: force chopping 16-bit input down to 8, in this case
+ * the app program can chose if both APIs are available by setting the
+ * correct scaling to use.
+ */
+# ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
+ /* For compatibility with previous versions use the strip method by
+ * default. This code works because if PNG_SCALE_16_TO_8 is already
+ * set the code below will do that in preference to the chop.
+ */
+ png_ptr->transformations |= PNG_16_TO_8;
+ info_ptr->bit_depth = 8;
+# else
+
+# ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
+ png_ptr->transformations |= PNG_SCALE_16_TO_8;
+ info_ptr->bit_depth = 8;
+# else
+
+ CONFIGURATION ERROR: you must enable at least one 16 to 8 method
+# endif
+# endif
+#endif /* !READ_16BIT */
+ }
+
+#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
+ if ((png_ptr->transformations & PNG_GRAY_TO_RGB) != 0)
+ info_ptr->color_type = (png_byte)(info_ptr->color_type |
+ PNG_COLOR_MASK_COLOR);
+#endif
+
+#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
+ if ((png_ptr->transformations & PNG_RGB_TO_GRAY) != 0)
+ info_ptr->color_type = (png_byte)(info_ptr->color_type &
+ ~PNG_COLOR_MASK_COLOR);
+#endif
+
+#ifdef PNG_READ_QUANTIZE_SUPPORTED
+ if ((png_ptr->transformations & PNG_QUANTIZE) != 0)
+ {
+ if (((info_ptr->color_type == PNG_COLOR_TYPE_RGB) ||
+ (info_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA)) &&
+ png_ptr->palette_lookup != 0 && info_ptr->bit_depth == 8)
+ {
+ info_ptr->color_type = PNG_COLOR_TYPE_PALETTE;
+ }
+ }
+#endif
+
+#ifdef PNG_READ_EXPAND_16_SUPPORTED
+ if ((png_ptr->transformations & PNG_EXPAND_16) != 0 &&
+ info_ptr->bit_depth == 8 &&
+ info_ptr->color_type != PNG_COLOR_TYPE_PALETTE)
+ {
+ info_ptr->bit_depth = 16;
+ }
+#endif
+
+#ifdef PNG_READ_PACK_SUPPORTED
+ if ((png_ptr->transformations & PNG_PACK) != 0 &&
+ (info_ptr->bit_depth < 8))
+ info_ptr->bit_depth = 8;
+#endif
+
+ if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
+ info_ptr->channels = 1;
+
+ else if ((info_ptr->color_type & PNG_COLOR_MASK_COLOR) != 0)
+ info_ptr->channels = 3;
+
+ else
+ info_ptr->channels = 1;
+
+#ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
+ if ((png_ptr->transformations & PNG_STRIP_ALPHA) != 0)
+ {
+ info_ptr->color_type = (png_byte)(info_ptr->color_type &
+ ~PNG_COLOR_MASK_ALPHA);
+ info_ptr->num_trans = 0;
+ }
+#endif
+
+ if ((info_ptr->color_type & PNG_COLOR_MASK_ALPHA) != 0)
+ info_ptr->channels++;
+
+#ifdef PNG_READ_FILLER_SUPPORTED
+ /* STRIP_ALPHA and FILLER allowed: MASK_ALPHA bit stripped above */
+ if ((png_ptr->transformations & PNG_FILLER) != 0 &&
+ (info_ptr->color_type == PNG_COLOR_TYPE_RGB ||
+ info_ptr->color_type == PNG_COLOR_TYPE_GRAY))
+ {
+ info_ptr->channels++;
+ /* If adding a true alpha channel not just filler */
+ if ((png_ptr->transformations & PNG_ADD_ALPHA) != 0)
+ info_ptr->color_type |= PNG_COLOR_MASK_ALPHA;
+ }
+#endif
+
+#if defined(PNG_USER_TRANSFORM_PTR_SUPPORTED) && \
+defined(PNG_READ_USER_TRANSFORM_SUPPORTED)
+ if ((png_ptr->transformations & PNG_USER_TRANSFORM) != 0)
+ {
+ if (info_ptr->bit_depth < png_ptr->user_transform_depth)
+ info_ptr->bit_depth = png_ptr->user_transform_depth;
+
+ if (info_ptr->channels < png_ptr->user_transform_channels)
+ info_ptr->channels = png_ptr->user_transform_channels;
+ }
+#endif
+
+ info_ptr->pixel_depth = (png_byte)(info_ptr->channels *
+ info_ptr->bit_depth);
+
+ info_ptr->rowbytes = PNG_ROWBYTES(info_ptr->pixel_depth, info_ptr->width);
+
+ /* Adding in 1.5.4: cache the above value in png_struct so that we can later
+ * check in png_rowbytes that the user buffer won't get overwritten. Note
+ * that the field is not always set - if png_read_update_info isn't called
+ * the application has to either not do any transforms or get the calculation
+ * right itself.
+ */
+ png_ptr->info_rowbytes = info_ptr->rowbytes;
+
+#ifndef PNG_READ_EXPAND_SUPPORTED
+ if (png_ptr != NULL)
+ return;
+#endif
+}
+
+#ifdef PNG_READ_PACK_SUPPORTED
+/* Unpack pixels of 1, 2, or 4 bits per pixel into 1 byte per pixel,
+ * without changing the actual values. Thus, if you had a row with
+ * a bit depth of 1, you would end up with bytes that only contained
+ * the numbers 0 or 1. If you would rather they contain 0 and 255, use
+ * png_do_shift() after this.
+ */
+static void
+png_do_unpack(png_row_infop row_info, png_bytep row)
+{
+ png_debug(1, "in png_do_unpack");
+
+ if (row_info->bit_depth < 8)
+ {
+ png_uint_32 i;
+ png_uint_32 row_width=row_info->width;
+
+ switch (row_info->bit_depth)
+ {
+ case 1:
+ {
+ png_bytep sp = row + (png_size_t)((row_width - 1) >> 3);
+ png_bytep dp = row + (png_size_t)row_width - 1;
+ png_uint_32 shift = 7 - (int)((row_width + 7) & 0x07);
+ for (i = 0; i < row_width; i++)
+ {
+ *dp = (png_byte)((*sp >> shift) & 0x01);
+
+ if (shift == 7)
+ {
+ shift = 0;
+ sp--;
+ }
+
+ else
+ shift++;
+
+ dp--;
+ }
+ break;
+ }
+
+ case 2:
+ {
+
+ png_bytep sp = row + (png_size_t)((row_width - 1) >> 2);
+ png_bytep dp = row + (png_size_t)row_width - 1;
+ png_uint_32 shift = (int)((3 - ((row_width + 3) & 0x03)) << 1);
+ for (i = 0; i < row_width; i++)
+ {
+ *dp = (png_byte)((*sp >> shift) & 0x03);
+
+ if (shift == 6)
+ {
+ shift = 0;
+ sp--;
+ }
+
+ else
+ shift += 2;
+
+ dp--;
+ }
+ break;
+ }
+
+ case 4:
+ {
+ png_bytep sp = row + (png_size_t)((row_width - 1) >> 1);
+ png_bytep dp = row + (png_size_t)row_width - 1;
+ png_uint_32 shift = (int)((1 - ((row_width + 1) & 0x01)) << 2);
+ for (i = 0; i < row_width; i++)
+ {
+ *dp = (png_byte)((*sp >> shift) & 0x0f);
+
+ if (shift == 4)
+ {
+ shift = 0;
+ sp--;
+ }
+
+ else
+ shift = 4;
+
+ dp--;
+ }
+ break;
+ }
+
+ default:
+ break;
+ }
+ row_info->bit_depth = 8;
+ row_info->pixel_depth = (png_byte)(8 * row_info->channels);
+ row_info->rowbytes = row_width * row_info->channels;
+ }
+}
+#endif
+
+#ifdef PNG_READ_SHIFT_SUPPORTED
+/* Reverse the effects of png_do_shift. This routine merely shifts the
+ * pixels back to their significant bits values. Thus, if you have
+ * a row of bit depth 8, but only 5 are significant, this will shift
+ * the values back to 0 through 31.
+ */
+static void
+png_do_unshift(png_row_infop row_info, png_bytep row,
+ png_const_color_8p sig_bits)
+{
+ int color_type;
+
+ png_debug(1, "in png_do_unshift");
+
+ /* The palette case has already been handled in the _init routine. */
+ color_type = row_info->color_type;
+
+ if (color_type != PNG_COLOR_TYPE_PALETTE)
+ {
+ int shift[4];
+ int channels = 0;
+ int bit_depth = row_info->bit_depth;
+
+ if ((color_type & PNG_COLOR_MASK_COLOR) != 0)
+ {
+ shift[channels++] = bit_depth - sig_bits->red;
+ shift[channels++] = bit_depth - sig_bits->green;
+ shift[channels++] = bit_depth - sig_bits->blue;
+ }
+
+ else
+ {
+ shift[channels++] = bit_depth - sig_bits->gray;
+ }
+
+ if ((color_type & PNG_COLOR_MASK_ALPHA) != 0)
+ {
+ shift[channels++] = bit_depth - sig_bits->alpha;
+ }
+
+ {
+ int c, have_shift;
+
+ for (c = have_shift = 0; c < channels; ++c)
+ {
+ /* A shift of more than the bit depth is an error condition but it
+ * gets ignored here.
+ */
+ if (shift[c] <= 0 || shift[c] >= bit_depth)
+ shift[c] = 0;
+
+ else
+ have_shift = 1;
+ }
+
+ if (have_shift == 0)
+ return;
+ }
+
+ switch (bit_depth)
+ {
+ default:
+ /* Must be 1bpp gray: should not be here! */
+ /* NOTREACHED */
+ break;
+
+ case 2:
+ /* Must be 2bpp gray */
+ /* assert(channels == 1 && shift[0] == 1) */
+ {
+ png_bytep bp = row;
+ png_bytep bp_end = bp + row_info->rowbytes;
+
+ while (bp < bp_end)
+ {
+ int b = (*bp >> 1) & 0x55;
+ *bp++ = (png_byte)b;
+ }
+ break;
+ }
+
+ case 4:
+ /* Must be 4bpp gray */
+ /* assert(channels == 1) */
+ {
+ png_bytep bp = row;
+ png_bytep bp_end = bp + row_info->rowbytes;
+ int gray_shift = shift[0];
+ int mask = 0xf >> gray_shift;
+
+ mask |= mask << 4;
+
+ while (bp < bp_end)
+ {
+ int b = (*bp >> gray_shift) & mask;
+ *bp++ = (png_byte)b;
+ }
+ break;
+ }
+
+ case 8:
+ /* Single byte components, G, GA, RGB, RGBA */
+ {
+ png_bytep bp = row;
+ png_bytep bp_end = bp + row_info->rowbytes;
+ int channel = 0;
+
+ while (bp < bp_end)
+ {
+ int b = *bp >> shift[channel];
+ if (++channel >= channels)
+ channel = 0;
+ *bp++ = (png_byte)b;
+ }
+ break;
+ }
+
+#ifdef PNG_READ_16BIT_SUPPORTED
+ case 16:
+ /* Double byte components, G, GA, RGB, RGBA */
+ {
+ png_bytep bp = row;
+ png_bytep bp_end = bp + row_info->rowbytes;
+ int channel = 0;
+
+ while (bp < bp_end)
+ {
+ int value = (bp[0] << 8) + bp[1];
+
+ value >>= shift[channel];
+ if (++channel >= channels)
+ channel = 0;
+ *bp++ = (png_byte)(value >> 8);
+ *bp++ = (png_byte)value;
+ }
+ break;
+ }
+#endif
+ }
+ }
+}
+#endif
+
+#ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
+/* Scale rows of bit depth 16 down to 8 accurately */
+static void
+png_do_scale_16_to_8(png_row_infop row_info, png_bytep row)
+{
+ png_debug(1, "in png_do_scale_16_to_8");
+
+ if (row_info->bit_depth == 16)
+ {
+ png_bytep sp = row; /* source */
+ png_bytep dp = row; /* destination */
+ png_bytep ep = sp + row_info->rowbytes; /* end+1 */
+
+ while (sp < ep)
+ {
+ /* The input is an array of 16 bit components, these must be scaled to
+ * 8 bits each. For a 16 bit value V the required value (from the PNG
+ * specification) is:
+ *
+ * (V * 255) / 65535
+ *
+ * This reduces to round(V / 257), or floor((V + 128.5)/257)
+ *
+ * Represent V as the two byte value vhi.vlo. Make a guess that the
+ * result is the top byte of V, vhi, then the correction to this value
+ * is:
+ *
+ * error = floor(((V-vhi.vhi) + 128.5) / 257)
+ * = floor(((vlo-vhi) + 128.5) / 257)
+ *
+ * This can be approximated using integer arithmetic (and a signed
+ * shift):
+ *
+ * error = (vlo-vhi+128) >> 8;
+ *
+ * The approximate differs from the exact answer only when (vlo-vhi) is
+ * 128; it then gives a correction of +1 when the exact correction is
+ * 0. This gives 128 errors. The exact answer (correct for all 16 bit
+ * input values) is:
+ *
+ * error = (vlo-vhi+128)*65535 >> 24;
+ *
+ * An alternative arithmetic calculation which also gives no errors is:
+ *
+ * (V * 255 + 32895) >> 16
+ */
+
+ png_int_32 tmp = *sp++; /* must be signed! */
+ tmp += (((int)*sp++ - tmp + 128) * 65535) >> 24;
+ *dp++ = (png_byte)tmp;
+ }
+
+ row_info->bit_depth = 8;
+ row_info->pixel_depth = (png_byte)(8 * row_info->channels);
+ row_info->rowbytes = row_info->width * row_info->channels;
+ }
+}
+#endif
+
+#ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
+static void
+/* Simply discard the low byte. This was the default behavior prior
+ * to libpng-1.5.4.
+ */
+png_do_chop(png_row_infop row_info, png_bytep row)
+{
+ png_debug(1, "in png_do_chop");
+
+ if (row_info->bit_depth == 16)
+ {
+ png_bytep sp = row; /* source */
+ png_bytep dp = row; /* destination */
+ png_bytep ep = sp + row_info->rowbytes; /* end+1 */
+
+ while (sp < ep)
+ {
+ *dp++ = *sp;
+ sp += 2; /* skip low byte */
+ }
+
+ row_info->bit_depth = 8;
+ row_info->pixel_depth = (png_byte)(8 * row_info->channels);
+ row_info->rowbytes = row_info->width * row_info->channels;
+ }
+}
+#endif
+
+#ifdef PNG_READ_SWAP_ALPHA_SUPPORTED
+static void
+png_do_read_swap_alpha(png_row_infop row_info, png_bytep row)
+{
+ png_debug(1, "in png_do_read_swap_alpha");
+
+ {
+ png_uint_32 row_width = row_info->width;
+ if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+ {
+ /* This converts from RGBA to ARGB */
+ if (row_info->bit_depth == 8)
+ {
+ png_bytep sp = row + row_info->rowbytes;
+ png_bytep dp = sp;
+ png_byte save;
+ png_uint_32 i;
+
+ for (i = 0; i < row_width; i++)
+ {
+ save = *(--sp);
+ *(--dp) = *(--sp);
+ *(--dp) = *(--sp);
+ *(--dp) = *(--sp);
+ *(--dp) = save;
+ }
+ }
+
+#ifdef PNG_READ_16BIT_SUPPORTED
+ /* This converts from RRGGBBAA to AARRGGBB */
+ else
+ {
+ png_bytep sp = row + row_info->rowbytes;
+ png_bytep dp = sp;
+ png_byte save[2];
+ png_uint_32 i;
+
+ for (i = 0; i < row_width; i++)
+ {
+ save[0] = *(--sp);
+ save[1] = *(--sp);
+ *(--dp) = *(--sp);
+ *(--dp) = *(--sp);
+ *(--dp) = *(--sp);
+ *(--dp) = *(--sp);
+ *(--dp) = *(--sp);
+ *(--dp) = *(--sp);
+ *(--dp) = save[0];
+ *(--dp) = save[1];
+ }
+ }
+#endif
+ }
+
+ else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
+ {
+ /* This converts from GA to AG */
+ if (row_info->bit_depth == 8)
+ {
+ png_bytep sp = row + row_info->rowbytes;
+ png_bytep dp = sp;
+ png_byte save;
+ png_uint_32 i;
+
+ for (i = 0; i < row_width; i++)
+ {
+ save = *(--sp);
+ *(--dp) = *(--sp);
+ *(--dp) = save;
+ }
+ }
+
+#ifdef PNG_READ_16BIT_SUPPORTED
+ /* This converts from GGAA to AAGG */
+ else
+ {
+ png_bytep sp = row + row_info->rowbytes;
+ png_bytep dp = sp;
+ png_byte save[2];
+ png_uint_32 i;
+
+ for (i = 0; i < row_width; i++)
+ {
+ save[0] = *(--sp);
+ save[1] = *(--sp);
+ *(--dp) = *(--sp);
+ *(--dp) = *(--sp);
+ *(--dp) = save[0];
+ *(--dp) = save[1];
+ }
+ }
+#endif
+ }
+ }
+}
+#endif
+
+#ifdef PNG_READ_INVERT_ALPHA_SUPPORTED
+static void
+png_do_read_invert_alpha(png_row_infop row_info, png_bytep row)
+{
+ png_uint_32 row_width;
+ png_debug(1, "in png_do_read_invert_alpha");
+
+ row_width = row_info->width;
+ if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+ {
+ if (row_info->bit_depth == 8)
+ {
+ /* This inverts the alpha channel in RGBA */
+ png_bytep sp = row + row_info->rowbytes;
+ png_bytep dp = sp;
+ png_uint_32 i;
+
+ for (i = 0; i < row_width; i++)
+ {
+ *(--dp) = (png_byte)(255 - *(--sp));
+
+/* This does nothing:
+ *(--dp) = *(--sp);
+ *(--dp) = *(--sp);
+ *(--dp) = *(--sp);
+ We can replace it with:
+*/
+ sp-=3;
+ dp=sp;
+ }
+ }
+
+#ifdef PNG_READ_16BIT_SUPPORTED
+ /* This inverts the alpha channel in RRGGBBAA */
+ else
+ {
+ png_bytep sp = row + row_info->rowbytes;
+ png_bytep dp = sp;
+ png_uint_32 i;
+
+ for (i = 0; i < row_width; i++)
+ {
+ *(--dp) = (png_byte)(255 - *(--sp));
+ *(--dp) = (png_byte)(255 - *(--sp));
+
+/* This does nothing:
+ *(--dp) = *(--sp);
+ *(--dp) = *(--sp);
+ *(--dp) = *(--sp);
+ *(--dp) = *(--sp);
+ *(--dp) = *(--sp);
+ *(--dp) = *(--sp);
+ We can replace it with:
+*/
+ sp-=6;
+ dp=sp;
+ }
+ }
+#endif
+ }
+ else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
+ {
+ if (row_info->bit_depth == 8)
+ {
+ /* This inverts the alpha channel in GA */
+ png_bytep sp = row + row_info->rowbytes;
+ png_bytep dp = sp;
+ png_uint_32 i;
+
+ for (i = 0; i < row_width; i++)
+ {
+ *(--dp) = (png_byte)(255 - *(--sp));
+ *(--dp) = *(--sp);
+ }
+ }
+
+#ifdef PNG_READ_16BIT_SUPPORTED
+ else
+ {
+ /* This inverts the alpha channel in GGAA */
+ png_bytep sp = row + row_info->rowbytes;
+ png_bytep dp = sp;
+ png_uint_32 i;
+
+ for (i = 0; i < row_width; i++)
+ {
+ *(--dp) = (png_byte)(255 - *(--sp));
+ *(--dp) = (png_byte)(255 - *(--sp));
+/*
+ *(--dp) = *(--sp);
+ *(--dp) = *(--sp);
+*/
+ sp-=2;
+ dp=sp;
+ }
+ }
+#endif
+ }
+}
+#endif
+
+#ifdef PNG_READ_FILLER_SUPPORTED
+/* Add filler channel if we have RGB color */
+static void
+png_do_read_filler(png_row_infop row_info, png_bytep row,
+ png_uint_32 filler, png_uint_32 flags)
+{
+ png_uint_32 i;
+ png_uint_32 row_width = row_info->width;
+
+#ifdef PNG_READ_16BIT_SUPPORTED
+ png_byte hi_filler = (png_byte)(filler>>8);
+#endif
+ png_byte lo_filler = (png_byte)filler;
+
+ png_debug(1, "in png_do_read_filler");
+
+ if (
+ row_info->color_type == PNG_COLOR_TYPE_GRAY)
+ {
+ if (row_info->bit_depth == 8)
+ {
+ if ((flags & PNG_FLAG_FILLER_AFTER) != 0)
+ {
+ /* This changes the data from G to GX */
+ png_bytep sp = row + (png_size_t)row_width;
+ png_bytep dp = sp + (png_size_t)row_width;
+ for (i = 1; i < row_width; i++)
+ {
+ *(--dp) = lo_filler;
+ *(--dp) = *(--sp);
+ }
+ *(--dp) = lo_filler;
+ row_info->channels = 2;
+ row_info->pixel_depth = 16;
+ row_info->rowbytes = row_width * 2;
+ }
+
+ else
+ {
+ /* This changes the data from G to XG */
+ png_bytep sp = row + (png_size_t)row_width;
+ png_bytep dp = sp + (png_size_t)row_width;
+ for (i = 0; i < row_width; i++)
+ {
+ *(--dp) = *(--sp);
+ *(--dp) = lo_filler;
+ }
+ row_info->channels = 2;
+ row_info->pixel_depth = 16;
+ row_info->rowbytes = row_width * 2;
+ }
+ }
+
+#ifdef PNG_READ_16BIT_SUPPORTED
+ else if (row_info->bit_depth == 16)
+ {
+ if ((flags & PNG_FLAG_FILLER_AFTER) != 0)
+ {
+ /* This changes the data from GG to GGXX */
+ png_bytep sp = row + (png_size_t)row_width * 2;
+ png_bytep dp = sp + (png_size_t)row_width * 2;
+ for (i = 1; i < row_width; i++)
+ {
+ *(--dp) = lo_filler;
+ *(--dp) = hi_filler;
+ *(--dp) = *(--sp);
+ *(--dp) = *(--sp);
+ }
+ *(--dp) = lo_filler;
+ *(--dp) = hi_filler;
+ row_info->channels = 2;
+ row_info->pixel_depth = 32;
+ row_info->rowbytes = row_width * 4;
+ }
+
+ else
+ {
+ /* This changes the data from GG to XXGG */
+ png_bytep sp = row + (png_size_t)row_width * 2;
+ png_bytep dp = sp + (png_size_t)row_width * 2;
+ for (i = 0; i < row_width; i++)
+ {
+ *(--dp) = *(--sp);
+ *(--dp) = *(--sp);
+ *(--dp) = lo_filler;
+ *(--dp) = hi_filler;
+ }
+ row_info->channels = 2;
+ row_info->pixel_depth = 32;
+ row_info->rowbytes = row_width * 4;
+ }
+ }
+#endif
+ } /* COLOR_TYPE == GRAY */
+ else if (row_info->color_type == PNG_COLOR_TYPE_RGB)
+ {
+ if (row_info->bit_depth == 8)
+ {
+ if ((flags & PNG_FLAG_FILLER_AFTER) != 0)
+ {
+ /* This changes the data from RGB to RGBX */
+ png_bytep sp = row + (png_size_t)row_width * 3;
+ png_bytep dp = sp + (png_size_t)row_width;
+ for (i = 1; i < row_width; i++)
+ {
+ *(--dp) = lo_filler;
+ *(--dp) = *(--sp);
+ *(--dp) = *(--sp);
+ *(--dp) = *(--sp);
+ }
+ *(--dp) = lo_filler;
+ row_info->channels = 4;
+ row_info->pixel_depth = 32;
+ row_info->rowbytes = row_width * 4;
+ }
+
+ else
+ {
+ /* This changes the data from RGB to XRGB */
+ png_bytep sp = row + (png_size_t)row_width * 3;
+ png_bytep dp = sp + (png_size_t)row_width;
+ for (i = 0; i < row_width; i++)
+ {
+ *(--dp) = *(--sp);
+ *(--dp) = *(--sp);
+ *(--dp) = *(--sp);
+ *(--dp) = lo_filler;
+ }
+ row_info->channels = 4;
+ row_info->pixel_depth = 32;
+ row_info->rowbytes = row_width * 4;
+ }
+ }
+
+#ifdef PNG_READ_16BIT_SUPPORTED
+ else if (row_info->bit_depth == 16)
+ {
+ if ((flags & PNG_FLAG_FILLER_AFTER) != 0)
+ {
+ /* This changes the data from RRGGBB to RRGGBBXX */
+ png_bytep sp = row + (png_size_t)row_width * 6;
+ png_bytep dp = sp + (png_size_t)row_width * 2;
+ for (i = 1; i < row_width; i++)
+ {
+ *(--dp) = lo_filler;
+ *(--dp) = hi_filler;
+ *(--dp) = *(--sp);
+ *(--dp) = *(--sp);
+ *(--dp) = *(--sp);
+ *(--dp) = *(--sp);
+ *(--dp) = *(--sp);
+ *(--dp) = *(--sp);
+ }
+ *(--dp) = lo_filler;
+ *(--dp) = hi_filler;
+ row_info->channels = 4;
+ row_info->pixel_depth = 64;
+ row_info->rowbytes = row_width * 8;
+ }
+
+ else
+ {
+ /* This changes the data from RRGGBB to XXRRGGBB */
+ png_bytep sp = row + (png_size_t)row_width * 6;
+ png_bytep dp = sp + (png_size_t)row_width * 2;
+ for (i = 0; i < row_width; i++)
+ {
+ *(--dp) = *(--sp);
+ *(--dp) = *(--sp);
+ *(--dp) = *(--sp);
+ *(--dp) = *(--sp);
+ *(--dp) = *(--sp);
+ *(--dp) = *(--sp);
+ *(--dp) = lo_filler;
+ *(--dp) = hi_filler;
+ }
+
+ row_info->channels = 4;
+ row_info->pixel_depth = 64;
+ row_info->rowbytes = row_width * 8;
+ }
+ }
+#endif
+ } /* COLOR_TYPE == RGB */
+}
+#endif
+
+#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
+/* Expand grayscale files to RGB, with or without alpha */
+static void
+png_do_gray_to_rgb(png_row_infop row_info, png_bytep row)
+{
+ png_uint_32 i;
+ png_uint_32 row_width = row_info->width;
+
+ png_debug(1, "in png_do_gray_to_rgb");
+
+ if (row_info->bit_depth >= 8 &&
+ (row_info->color_type & PNG_COLOR_MASK_COLOR) == 0)
+ {
+ if (row_info->color_type == PNG_COLOR_TYPE_GRAY)
+ {
+ if (row_info->bit_depth == 8)
+ {
+ /* This changes G to RGB */
+ png_bytep sp = row + (png_size_t)row_width - 1;
+ png_bytep dp = sp + (png_size_t)row_width * 2;
+ for (i = 0; i < row_width; i++)
+ {
+ *(dp--) = *sp;
+ *(dp--) = *sp;
+ *(dp--) = *(sp--);
+ }
+ }
+
+ else
+ {
+ /* This changes GG to RRGGBB */
+ png_bytep sp = row + (png_size_t)row_width * 2 - 1;
+ png_bytep dp = sp + (png_size_t)row_width * 4;
+ for (i = 0; i < row_width; i++)
+ {
+ *(dp--) = *sp;
+ *(dp--) = *(sp - 1);
+ *(dp--) = *sp;
+ *(dp--) = *(sp - 1);
+ *(dp--) = *(sp--);
+ *(dp--) = *(sp--);
+ }
+ }
+ }
+
+ else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
+ {
+ if (row_info->bit_depth == 8)
+ {
+ /* This changes GA to RGBA */
+ png_bytep sp = row + (png_size_t)row_width * 2 - 1;
+ png_bytep dp = sp + (png_size_t)row_width * 2;
+ for (i = 0; i < row_width; i++)
+ {
+ *(dp--) = *(sp--);
+ *(dp--) = *sp;
+ *(dp--) = *sp;
+ *(dp--) = *(sp--);
+ }
+ }
+
+ else
+ {
+ /* This changes GGAA to RRGGBBAA */
+ png_bytep sp = row + (png_size_t)row_width * 4 - 1;
+ png_bytep dp = sp + (png_size_t)row_width * 4;
+ for (i = 0; i < row_width; i++)
+ {
+ *(dp--) = *(sp--);
+ *(dp--) = *(sp--);
+ *(dp--) = *sp;
+ *(dp--) = *(sp - 1);
+ *(dp--) = *sp;
+ *(dp--) = *(sp - 1);
+ *(dp--) = *(sp--);
+ *(dp--) = *(sp--);
+ }
+ }
+ }
+ row_info->channels = (png_byte)(row_info->channels + 2);
+ row_info->color_type |= PNG_COLOR_MASK_COLOR;
+ row_info->pixel_depth = (png_byte)(row_info->channels *
+ row_info->bit_depth);
+ row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_width);
+ }
+}
+#endif
+
+#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
+/* Reduce RGB files to grayscale, with or without alpha
+ * using the equation given in Poynton's ColorFAQ of 1998-01-04 at
+ * <http://www.inforamp.net/~poynton/> (THIS LINK IS DEAD June 2008 but
+ * versions dated 1998 through November 2002 have been archived at
+ * http://web.archive.org/web/20000816232553/http://www.inforamp.net/
+ * ~poynton/notes/colour_and_gamma/ColorFAQ.txt )
+ * Charles Poynton poynton at poynton.com
+ *
+ * Y = 0.212671 * R + 0.715160 * G + 0.072169 * B
+ *
+ * which can be expressed with integers as
+ *
+ * Y = (6969 * R + 23434 * G + 2365 * B)/32768
+ *
+ * Poynton's current link (as of January 2003 through July 2011):
+ * <http://www.poynton.com/notes/colour_and_gamma/>
+ * has changed the numbers slightly:
+ *
+ * Y = 0.2126*R + 0.7152*G + 0.0722*B
+ *
+ * which can be expressed with integers as
+ *
+ * Y = (6966 * R + 23436 * G + 2366 * B)/32768
+ *
+ * Historically, however, libpng uses numbers derived from the ITU-R Rec 709
+ * end point chromaticities and the D65 white point. Depending on the
+ * precision used for the D65 white point this produces a variety of different
+ * numbers, however if the four decimal place value used in ITU-R Rec 709 is
+ * used (0.3127,0.3290) the Y calculation would be:
+ *
+ * Y = (6968 * R + 23435 * G + 2366 * B)/32768
+ *
+ * While this is correct the rounding results in an overflow for white, because
+ * the sum of the rounded coefficients is 32769, not 32768. Consequently
+ * libpng uses, instead, the closest non-overflowing approximation:
+ *
+ * Y = (6968 * R + 23434 * G + 2366 * B)/32768
+ *
+ * Starting with libpng-1.5.5, if the image being converted has a cHRM chunk
+ * (including an sRGB chunk) then the chromaticities are used to calculate the
+ * coefficients. See the chunk handling in pngrutil.c for more information.
+ *
+ * In all cases the calculation is to be done in a linear colorspace. If no
+ * gamma information is available to correct the encoding of the original RGB
+ * values this results in an implicit assumption that the original PNG RGB
+ * values were linear.
+ *
+ * Other integer coefficents can be used via png_set_rgb_to_gray(). Because
+ * the API takes just red and green coefficients the blue coefficient is
+ * calculated to make the sum 32768. This will result in different rounding
+ * to that used above.
+ */
+static int
+png_do_rgb_to_gray(png_structrp png_ptr, png_row_infop row_info, png_bytep row)
+
+{
+ int rgb_error = 0;
+
+ png_debug(1, "in png_do_rgb_to_gray");
+
+ if ((row_info->color_type & PNG_COLOR_MASK_PALETTE) == 0 &&
+ (row_info->color_type & PNG_COLOR_MASK_COLOR) != 0)
+ {
+ PNG_CONST png_uint_32 rc = png_ptr->rgb_to_gray_red_coeff;
+ PNG_CONST png_uint_32 gc = png_ptr->rgb_to_gray_green_coeff;
+ PNG_CONST png_uint_32 bc = 32768 - rc - gc;
+ PNG_CONST png_uint_32 row_width = row_info->width;
+ PNG_CONST int have_alpha =
+ (row_info->color_type & PNG_COLOR_MASK_ALPHA) != 0;
+
+ if (row_info->bit_depth == 8)
+ {
+#ifdef PNG_READ_GAMMA_SUPPORTED
+ /* Notice that gamma to/from 1 are not necessarily inverses (if
+ * there is an overall gamma correction). Prior to 1.5.5 this code
+ * checked the linearized values for equality; this doesn't match
+ * the documentation, the original values must be checked.
+ */
+ if (png_ptr->gamma_from_1 != NULL && png_ptr->gamma_to_1 != NULL)
+ {
+ png_bytep sp = row;
+ png_bytep dp = row;
+ png_uint_32 i;
+
+ for (i = 0; i < row_width; i++)
+ {
+ png_byte red = *(sp++);
+ png_byte green = *(sp++);
+ png_byte blue = *(sp++);
+
+ if (red != green || red != blue)
+ {
+ red = png_ptr->gamma_to_1[red];
+ green = png_ptr->gamma_to_1[green];
+ blue = png_ptr->gamma_to_1[blue];
+
+ rgb_error |= 1;
+ *(dp++) = png_ptr->gamma_from_1[
+ (rc*red + gc*green + bc*blue + 16384)>>15];
+ }
+
+ else
+ {
+ /* If there is no overall correction the table will not be
+ * set.
+ */
+ if (png_ptr->gamma_table != NULL)
+ red = png_ptr->gamma_table[red];
+
+ *(dp++) = red;
+ }
+
+ if (have_alpha != 0)
+ *(dp++) = *(sp++);
+ }
+ }
+ else
+#endif
+ {
+ png_bytep sp = row;
+ png_bytep dp = row;
+ png_uint_32 i;
+
+ for (i = 0; i < row_width; i++)
+ {
+ png_byte red = *(sp++);
+ png_byte green = *(sp++);
+ png_byte blue = *(sp++);
+
+ if (red != green || red != blue)
+ {
+ rgb_error |= 1;
+ /* NOTE: this is the historical approach which simply
+ * truncates the results.
+ */
+ *(dp++) = (png_byte)((rc*red + gc*green + bc*blue)>>15);
+ }
+
+ else
+ *(dp++) = red;
+
+ if (have_alpha != 0)
+ *(dp++) = *(sp++);
+ }
+ }
+ }
+
+ else /* RGB bit_depth == 16 */
+ {
+#ifdef PNG_READ_GAMMA_SUPPORTED
+ if (png_ptr->gamma_16_to_1 != NULL && png_ptr->gamma_16_from_1 != NULL)
+ {
+ png_bytep sp = row;
+ png_bytep dp = row;
+ png_uint_32 i;
+
+ for (i = 0; i < row_width; i++)
+ {
+ png_uint_16 red, green, blue, w;
+ png_byte hi,lo;
+
+ hi=*(sp)++; lo=*(sp)++; red = (png_uint_16)((hi << 8) | (lo));
+ hi=*(sp)++; lo=*(sp)++; green = (png_uint_16)((hi << 8) | (lo));
+ hi=*(sp)++; lo=*(sp)++; blue = (png_uint_16)((hi << 8) | (lo));
+
+ if (red == green && red == blue)
+ {
+ if (png_ptr->gamma_16_table != NULL)
+ w = png_ptr->gamma_16_table[(red & 0xff)
+ >> png_ptr->gamma_shift][red >> 8];
+
+ else
+ w = red;
+ }
+
+ else
+ {
+ png_uint_16 red_1 = png_ptr->gamma_16_to_1[(red & 0xff)
+ >> png_ptr->gamma_shift][red>>8];
+ png_uint_16 green_1 =
+ png_ptr->gamma_16_to_1[(green & 0xff) >>
+ png_ptr->gamma_shift][green>>8];
+ png_uint_16 blue_1 = png_ptr->gamma_16_to_1[(blue & 0xff)
+ >> png_ptr->gamma_shift][blue>>8];
+ png_uint_16 gray16 = (png_uint_16)((rc*red_1 + gc*green_1
+ + bc*blue_1 + 16384)>>15);
+ w = png_ptr->gamma_16_from_1[(gray16 & 0xff) >>
+ png_ptr->gamma_shift][gray16 >> 8];
+ rgb_error |= 1;
+ }
+
+ *(dp++) = (png_byte)((w>>8) & 0xff);
+ *(dp++) = (png_byte)(w & 0xff);
+
+ if (have_alpha != 0)
+ {
+ *(dp++) = *(sp++);
+ *(dp++) = *(sp++);
+ }
+ }
+ }
+ else
+#endif
+ {
+ png_bytep sp = row;
+ png_bytep dp = row;
+ png_uint_32 i;
+
+ for (i = 0; i < row_width; i++)
+ {
+ png_uint_16 red, green, blue, gray16;
+ png_byte hi,lo;
+
+ hi=*(sp)++; lo=*(sp)++; red = (png_uint_16)((hi << 8) | (lo));
+ hi=*(sp)++; lo=*(sp)++; green = (png_uint_16)((hi << 8) | (lo));
+ hi=*(sp)++; lo=*(sp)++; blue = (png_uint_16)((hi << 8) | (lo));
+
+ if (red != green || red != blue)
+ rgb_error |= 1;
+
+ /* From 1.5.5 in the 16 bit case do the accurate conversion even
+ * in the 'fast' case - this is because this is where the code
+ * ends up when handling linear 16 bit data.
+ */
+ gray16 = (png_uint_16)((rc*red + gc*green + bc*blue + 16384) >>
+ 15);
+ *(dp++) = (png_byte)((gray16 >> 8) & 0xff);
+ *(dp++) = (png_byte)(gray16 & 0xff);
+
+ if (have_alpha != 0)
+ {
+ *(dp++) = *(sp++);
+ *(dp++) = *(sp++);
+ }
+ }
+ }
+ }
+
+ row_info->channels = (png_byte)(row_info->channels - 2);
+ row_info->color_type = (png_byte)(row_info->color_type &
+ ~PNG_COLOR_MASK_COLOR);
+ row_info->pixel_depth = (png_byte)(row_info->channels *
+ row_info->bit_depth);
+ row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_width);
+ }
+ return rgb_error;
+}
+#endif
+
+#if defined(PNG_READ_BACKGROUND_SUPPORTED) ||\
+ defined(PNG_READ_ALPHA_MODE_SUPPORTED)
+/* Replace any alpha or transparency with the supplied background color.
+ * "background" is already in the screen gamma, while "background_1" is
+ * at a gamma of 1.0. Paletted files have already been taken care of.
+ */
+static void
+png_do_compose(png_row_infop row_info, png_bytep row, png_structrp png_ptr)
+{
+#ifdef PNG_READ_GAMMA_SUPPORTED
+ png_const_bytep gamma_table = png_ptr->gamma_table;
+ png_const_bytep gamma_from_1 = png_ptr->gamma_from_1;
+ png_const_bytep gamma_to_1 = png_ptr->gamma_to_1;
+ png_const_uint_16pp gamma_16 = png_ptr->gamma_16_table;
+ png_const_uint_16pp gamma_16_from_1 = png_ptr->gamma_16_from_1;
+ png_const_uint_16pp gamma_16_to_1 = png_ptr->gamma_16_to_1;
+ int gamma_shift = png_ptr->gamma_shift;
+ int optimize = (png_ptr->flags & PNG_FLAG_OPTIMIZE_ALPHA) != 0;
+#endif
+
+ png_bytep sp;
+ png_uint_32 i;
+ png_uint_32 row_width = row_info->width;
+ int shift;
+
+ png_debug(1, "in png_do_compose");
+
+ {
+ switch (row_info->color_type)
+ {
+ case PNG_COLOR_TYPE_GRAY:
+ {
+ switch (row_info->bit_depth)
+ {
+ case 1:
+ {
+ sp = row;
+ shift = 7;
+ for (i = 0; i < row_width; i++)
+ {
+ if ((png_uint_16)((*sp >> shift) & 0x01)
+ == png_ptr->trans_color.gray)
+ {
+ unsigned int tmp = *sp & (0x7f7f >> (7 - shift));
+ tmp |= png_ptr->background.gray << shift;
+ *sp = (png_byte)(tmp & 0xff);
+ }
+
+ if (shift == 0)
+ {
+ shift = 7;
+ sp++;
+ }
+
+ else
+ shift--;
+ }
+ break;
+ }
+
+ case 2:
+ {
+#ifdef PNG_READ_GAMMA_SUPPORTED
+ if (gamma_table != NULL)
+ {
+ sp = row;
+ shift = 6;
+ for (i = 0; i < row_width; i++)
+ {
+ if ((png_uint_16)((*sp >> shift) & 0x03)
+ == png_ptr->trans_color.gray)
+ {
+ unsigned int tmp = *sp & (0x3f3f >> (6 - shift));
+ tmp |= png_ptr->background.gray << shift;
+ *sp = (png_byte)(tmp & 0xff);
+ }
+
+ else
+ {
+ unsigned int p = (*sp >> shift) & 0x03;
+ unsigned int g = (gamma_table [p | (p << 2) |
+ (p << 4) | (p << 6)] >> 6) & 0x03;
+ unsigned int tmp = *sp & (0x3f3f >> (6 - shift));
+ tmp |= g << shift;
+ *sp = (png_byte)(tmp & 0xff);
+ }
+
+ if (shift == 0)
+ {
+ shift = 6;
+ sp++;
+ }
+
+ else
+ shift -= 2;
+ }
+ }
+
+ else
+#endif
+ {
+ sp = row;
+ shift = 6;
+ for (i = 0; i < row_width; i++)
+ {
+ if ((png_uint_16)((*sp >> shift) & 0x03)
+ == png_ptr->trans_color.gray)
+ {
+ unsigned int tmp = *sp & (0x3f3f >> (6 - shift));
+ tmp |= png_ptr->background.gray << shift;
+ *sp = (png_byte)(tmp & 0xff);
+ }
+
+ if (shift == 0)
+ {
+ shift = 6;
+ sp++;
+ }
+
+ else
+ shift -= 2;
+ }
+ }
+ break;
+ }
+
+ case 4:
+ {
+#ifdef PNG_READ_GAMMA_SUPPORTED
+ if (gamma_table != NULL)
+ {
+ sp = row;
+ shift = 4;
+ for (i = 0; i < row_width; i++)
+ {
+ if ((png_uint_16)((*sp >> shift) & 0x0f)
+ == png_ptr->trans_color.gray)
+ {
+ unsigned int tmp = *sp & (0xf0f >> (4 - shift));
+ tmp |= png_ptr->background.gray << shift;
+ *sp = (png_byte)(tmp & 0xff);
+ }
+
+ else
+ {
+ unsigned int p = (*sp >> shift) & 0x0f;
+ unsigned int g = (gamma_table[p | (p << 4)] >> 4) &
+ 0x0f;
+ unsigned int tmp = *sp & (0xf0f >> (4 - shift));
+ tmp |= g << shift;
+ *sp = (png_byte)(tmp & 0xff);
+ }
+
+ if (shift == 0)
+ {
+ shift = 4;
+ sp++;
+ }
+
+ else
+ shift -= 4;
+ }
+ }
+
+ else
+#endif
+ {
+ sp = row;
+ shift = 4;
+ for (i = 0; i < row_width; i++)
+ {
+ if ((png_uint_16)((*sp >> shift) & 0x0f)
+ == png_ptr->trans_color.gray)
+ {
+ unsigned int tmp = *sp & (0xf0f >> (4 - shift));
+ tmp |= png_ptr->background.gray << shift;
+ *sp = (png_byte)(tmp & 0xff);
+ }
+
+ if (shift == 0)
+ {
+ shift = 4;
+ sp++;
+ }
+
+ else
+ shift -= 4;
+ }
+ }
+ break;
+ }
+
+ case 8:
+ {
+#ifdef PNG_READ_GAMMA_SUPPORTED
+ if (gamma_table != NULL)
+ {
+ sp = row;
+ for (i = 0; i < row_width; i++, sp++)
+ {
+ if (*sp == png_ptr->trans_color.gray)
+ *sp = (png_byte)png_ptr->background.gray;
+
+ else
+ *sp = gamma_table[*sp];
+ }
+ }
+ else
+#endif
+ {
+ sp = row;
+ for (i = 0; i < row_width; i++, sp++)
+ {
+ if (*sp == png_ptr->trans_color.gray)
+ *sp = (png_byte)png_ptr->background.gray;
+ }
+ }
+ break;
+ }
+
+ case 16:
+ {
+#ifdef PNG_READ_GAMMA_SUPPORTED
+ if (gamma_16 != NULL)
+ {
+ sp = row;
+ for (i = 0; i < row_width; i++, sp += 2)
+ {
+ png_uint_16 v;
+
+ v = (png_uint_16)(((*sp) << 8) + *(sp + 1));
+
+ if (v == png_ptr->trans_color.gray)
+ {
+ /* Background is already in screen gamma */
+ *sp = (png_byte)((png_ptr->background.gray >> 8)
+ & 0xff);
+ *(sp + 1) = (png_byte)(png_ptr->background.gray
+ & 0xff);
+ }
+
+ else
+ {
+ v = gamma_16[*(sp + 1) >> gamma_shift][*sp];
+ *sp = (png_byte)((v >> 8) & 0xff);
+ *(sp + 1) = (png_byte)(v & 0xff);
+ }
+ }
+ }
+ else
+#endif
+ {
+ sp = row;
+ for (i = 0; i < row_width; i++, sp += 2)
+ {
+ png_uint_16 v;
+
+ v = (png_uint_16)(((*sp) << 8) + *(sp + 1));
+
+ if (v == png_ptr->trans_color.gray)
+ {
+ *sp = (png_byte)((png_ptr->background.gray >> 8)
+ & 0xff);
+ *(sp + 1) = (png_byte)(png_ptr->background.gray
+ & 0xff);
+ }
+ }
+ }
+ break;
+ }
+
+ default:
+ break;
+ }
+ break;
+ }
+
+ case PNG_COLOR_TYPE_RGB:
+ {
+ if (row_info->bit_depth == 8)
+ {
+#ifdef PNG_READ_GAMMA_SUPPORTED
+ if (gamma_table != NULL)
+ {
+ sp = row;
+ for (i = 0; i < row_width; i++, sp += 3)
+ {
+ if (*sp == png_ptr->trans_color.red &&
+ *(sp + 1) == png_ptr->trans_color.green &&
+ *(sp + 2) == png_ptr->trans_color.blue)
+ {
+ *sp = (png_byte)png_ptr->background.red;
+ *(sp + 1) = (png_byte)png_ptr->background.green;
+ *(sp + 2) = (png_byte)png_ptr->background.blue;
+ }
+
+ else
+ {
+ *sp = gamma_table[*sp];
+ *(sp + 1) = gamma_table[*(sp + 1)];
+ *(sp + 2) = gamma_table[*(sp + 2)];
+ }
+ }
+ }
+ else
+#endif
+ {
+ sp = row;
+ for (i = 0; i < row_width; i++, sp += 3)
+ {
+ if (*sp == png_ptr->trans_color.red &&
+ *(sp + 1) == png_ptr->trans_color.green &&
+ *(sp + 2) == png_ptr->trans_color.blue)
+ {
+ *sp = (png_byte)png_ptr->background.red;
+ *(sp + 1) = (png_byte)png_ptr->background.green;
+ *(sp + 2) = (png_byte)png_ptr->background.blue;
+ }
+ }
+ }
+ }
+ else /* if (row_info->bit_depth == 16) */
+ {
+#ifdef PNG_READ_GAMMA_SUPPORTED
+ if (gamma_16 != NULL)
+ {
+ sp = row;
+ for (i = 0; i < row_width; i++, sp += 6)
+ {
+ png_uint_16 r = (png_uint_16)(((*sp) << 8) + *(sp + 1));
+
+ png_uint_16 g = (png_uint_16)(((*(sp + 2)) << 8)
+ + *(sp + 3));
+
+ png_uint_16 b = (png_uint_16)(((*(sp + 4)) << 8)
+ + *(sp + 5));
+
+ if (r == png_ptr->trans_color.red &&
+ g == png_ptr->trans_color.green &&
+ b == png_ptr->trans_color.blue)
+ {
+ /* Background is already in screen gamma */
+ *sp = (png_byte)((png_ptr->background.red >> 8) & 0xff);
+ *(sp + 1) = (png_byte)(png_ptr->background.red & 0xff);
+ *(sp + 2) = (png_byte)((png_ptr->background.green >> 8)
+ & 0xff);
+ *(sp + 3) = (png_byte)(png_ptr->background.green
+ & 0xff);
+ *(sp + 4) = (png_byte)((png_ptr->background.blue >> 8)
+ & 0xff);
+ *(sp + 5) = (png_byte)(png_ptr->background.blue & 0xff);
+ }
+
+ else
+ {
+ png_uint_16 v = gamma_16[*(sp + 1) >> gamma_shift][*sp];
+ *sp = (png_byte)((v >> 8) & 0xff);
+ *(sp + 1) = (png_byte)(v & 0xff);
+
+ v = gamma_16[*(sp + 3) >> gamma_shift][*(sp + 2)];
+ *(sp + 2) = (png_byte)((v >> 8) & 0xff);
+ *(sp + 3) = (png_byte)(v & 0xff);
+
+ v = gamma_16[*(sp + 5) >> gamma_shift][*(sp + 4)];
+ *(sp + 4) = (png_byte)((v >> 8) & 0xff);
+ *(sp + 5) = (png_byte)(v & 0xff);
+ }
+ }
+ }
+
+ else
+#endif
+ {
+ sp = row;
+ for (i = 0; i < row_width; i++, sp += 6)
+ {
+ png_uint_16 r = (png_uint_16)(((*sp) << 8) + *(sp + 1));
+
+ png_uint_16 g = (png_uint_16)(((*(sp + 2)) << 8)
+ + *(sp + 3));
+
+ png_uint_16 b = (png_uint_16)(((*(sp + 4)) << 8)
+ + *(sp + 5));
+
+ if (r == png_ptr->trans_color.red &&
+ g == png_ptr->trans_color.green &&
+ b == png_ptr->trans_color.blue)
+ {
+ *sp = (png_byte)((png_ptr->background.red >> 8) & 0xff);
+ *(sp + 1) = (png_byte)(png_ptr->background.red & 0xff);
+ *(sp + 2) = (png_byte)((png_ptr->background.green >> 8)
+ & 0xff);
+ *(sp + 3) = (png_byte)(png_ptr->background.green
+ & 0xff);
+ *(sp + 4) = (png_byte)((png_ptr->background.blue >> 8)
+ & 0xff);
+ *(sp + 5) = (png_byte)(png_ptr->background.blue & 0xff);
+ }
+ }
+ }
+ }
+ break;
+ }
+
+ case PNG_COLOR_TYPE_GRAY_ALPHA:
+ {
+ if (row_info->bit_depth == 8)
+ {
+#ifdef PNG_READ_GAMMA_SUPPORTED
+ if (gamma_to_1 != NULL && gamma_from_1 != NULL &&
+ gamma_table != NULL)
+ {
+ sp = row;
+ for (i = 0; i < row_width; i++, sp += 2)
+ {
+ png_uint_16 a = *(sp + 1);
+
+ if (a == 0xff)
+ *sp = gamma_table[*sp];
+
+ else if (a == 0)
+ {
+ /* Background is already in screen gamma */
+ *sp = (png_byte)png_ptr->background.gray;
+ }
+
+ else
+ {
+ png_byte v, w;
+
+ v = gamma_to_1[*sp];
+ png_composite(w, v, a, png_ptr->background_1.gray);
+ if (optimize == 0)
+ w = gamma_from_1[w];
+ *sp = w;
+ }
+ }
+ }
+ else
+#endif
+ {
+ sp = row;
+ for (i = 0; i < row_width; i++, sp += 2)
+ {
+ png_byte a = *(sp + 1);
+
+ if (a == 0)
+ *sp = (png_byte)png_ptr->background.gray;
+
+ else if (a < 0xff)
+ png_composite(*sp, *sp, a, png_ptr->background.gray);
+ }
+ }
+ }
+ else /* if (png_ptr->bit_depth == 16) */
+ {
+#ifdef PNG_READ_GAMMA_SUPPORTED
+ if (gamma_16 != NULL && gamma_16_from_1 != NULL &&
+ gamma_16_to_1 != NULL)
+ {
+ sp = row;
+ for (i = 0; i < row_width; i++, sp += 4)
+ {
+ png_uint_16 a = (png_uint_16)(((*(sp + 2)) << 8)
+ + *(sp + 3));
+
+ if (a == (png_uint_16)0xffff)
+ {
+ png_uint_16 v;
+
+ v = gamma_16[*(sp + 1) >> gamma_shift][*sp];
+ *sp = (png_byte)((v >> 8) & 0xff);
+ *(sp + 1) = (png_byte)(v & 0xff);
+ }
+
+ else if (a == 0)
+ {
+ /* Background is already in screen gamma */
+ *sp = (png_byte)((png_ptr->background.gray >> 8)
+ & 0xff);
+ *(sp + 1) = (png_byte)(png_ptr->background.gray & 0xff);
+ }
+
+ else
+ {
+ png_uint_16 g, v, w;
+
+ g = gamma_16_to_1[*(sp + 1) >> gamma_shift][*sp];
+ png_composite_16(v, g, a, png_ptr->background_1.gray);
+ if (optimize != 0)
+ w = v;
+ else
+ w = gamma_16_from_1[(v & 0xff) >>
+ gamma_shift][v >> 8];
+ *sp = (png_byte)((w >> 8) & 0xff);
+ *(sp + 1) = (png_byte)(w & 0xff);
+ }
+ }
+ }
+ else
+#endif
+ {
+ sp = row;
+ for (i = 0; i < row_width; i++, sp += 4)
+ {
+ png_uint_16 a = (png_uint_16)(((*(sp + 2)) << 8)
+ + *(sp + 3));
+
+ if (a == 0)
+ {
+ *sp = (png_byte)((png_ptr->background.gray >> 8)
+ & 0xff);
+ *(sp + 1) = (png_byte)(png_ptr->background.gray & 0xff);
+ }
+
+ else if (a < 0xffff)
+ {
+ png_uint_16 g, v;
+
+ g = (png_uint_16)(((*sp) << 8) + *(sp + 1));
+ png_composite_16(v, g, a, png_ptr->background.gray);
+ *sp = (png_byte)((v >> 8) & 0xff);
+ *(sp + 1) = (png_byte)(v & 0xff);
+ }
+ }
+ }
+ }
+ break;
+ }
+
+ case PNG_COLOR_TYPE_RGB_ALPHA:
+ {
+ if (row_info->bit_depth == 8)
+ {
+#ifdef PNG_READ_GAMMA_SUPPORTED
+ if (gamma_to_1 != NULL && gamma_from_1 != NULL &&
+ gamma_table != NULL)
+ {
+ sp = row;
+ for (i = 0; i < row_width; i++, sp += 4)
+ {
+ png_byte a = *(sp + 3);
+
+ if (a == 0xff)
+ {
+ *sp = gamma_table[*sp];
+ *(sp + 1) = gamma_table[*(sp + 1)];
+ *(sp + 2) = gamma_table[*(sp + 2)];
+ }
+
+ else if (a == 0)
+ {
+ /* Background is already in screen gamma */
+ *sp = (png_byte)png_ptr->background.red;
+ *(sp + 1) = (png_byte)png_ptr->background.green;
+ *(sp + 2) = (png_byte)png_ptr->background.blue;
+ }
+
+ else
+ {
+ png_byte v, w;
+
+ v = gamma_to_1[*sp];
+ png_composite(w, v, a, png_ptr->background_1.red);
+ if (optimize == 0) w = gamma_from_1[w];
+ *sp = w;
+
+ v = gamma_to_1[*(sp + 1)];
+ png_composite(w, v, a, png_ptr->background_1.green);
+ if (optimize == 0) w = gamma_from_1[w];
+ *(sp + 1) = w;
+
+ v = gamma_to_1[*(sp + 2)];
+ png_composite(w, v, a, png_ptr->background_1.blue);
+ if (optimize == 0) w = gamma_from_1[w];
+ *(sp + 2) = w;
+ }
+ }
+ }
+ else
+#endif
+ {
+ sp = row;
+ for (i = 0; i < row_width; i++, sp += 4)
+ {
+ png_byte a = *(sp + 3);
+
+ if (a == 0)
+ {
+ *sp = (png_byte)png_ptr->background.red;
+ *(sp + 1) = (png_byte)png_ptr->background.green;
+ *(sp + 2) = (png_byte)png_ptr->background.blue;
+ }
+
+ else if (a < 0xff)
+ {
+ png_composite(*sp, *sp, a, png_ptr->background.red);
+
+ png_composite(*(sp + 1), *(sp + 1), a,
+ png_ptr->background.green);
+
+ png_composite(*(sp + 2), *(sp + 2), a,
+ png_ptr->background.blue);
+ }
+ }
+ }
+ }
+ else /* if (row_info->bit_depth == 16) */
+ {
+#ifdef PNG_READ_GAMMA_SUPPORTED
+ if (gamma_16 != NULL && gamma_16_from_1 != NULL &&
+ gamma_16_to_1 != NULL)
+ {
+ sp = row;
+ for (i = 0; i < row_width; i++, sp += 8)
+ {
+ png_uint_16 a = (png_uint_16)(((png_uint_16)(*(sp + 6))
+ << 8) + (png_uint_16)(*(sp + 7)));
+
+ if (a == (png_uint_16)0xffff)
+ {
+ png_uint_16 v;
+
+ v = gamma_16[*(sp + 1) >> gamma_shift][*sp];
+ *sp = (png_byte)((v >> 8) & 0xff);
+ *(sp + 1) = (png_byte)(v & 0xff);
+
+ v = gamma_16[*(sp + 3) >> gamma_shift][*(sp + 2)];
+ *(sp + 2) = (png_byte)((v >> 8) & 0xff);
+ *(sp + 3) = (png_byte)(v & 0xff);
+
+ v = gamma_16[*(sp + 5) >> gamma_shift][*(sp + 4)];
+ *(sp + 4) = (png_byte)((v >> 8) & 0xff);
+ *(sp + 5) = (png_byte)(v & 0xff);
+ }
+
+ else if (a == 0)
+ {
+ /* Background is already in screen gamma */
+ *sp = (png_byte)((png_ptr->background.red >> 8) & 0xff);
+ *(sp + 1) = (png_byte)(png_ptr->background.red & 0xff);
+ *(sp + 2) = (png_byte)((png_ptr->background.green >> 8)
+ & 0xff);
+ *(sp + 3) = (png_byte)(png_ptr->background.green
+ & 0xff);
+ *(sp + 4) = (png_byte)((png_ptr->background.blue >> 8)
+ & 0xff);
+ *(sp + 5) = (png_byte)(png_ptr->background.blue & 0xff);
+ }
+
+ else
+ {
+ png_uint_16 v, w;
+
+ v = gamma_16_to_1[*(sp + 1) >> gamma_shift][*sp];
+ png_composite_16(w, v, a, png_ptr->background_1.red);
+ if (optimize == 0)
+ w = gamma_16_from_1[((w & 0xff) >> gamma_shift)][w >>
+ 8];
+ *sp = (png_byte)((w >> 8) & 0xff);
+ *(sp + 1) = (png_byte)(w & 0xff);
+
+ v = gamma_16_to_1[*(sp + 3) >> gamma_shift][*(sp + 2)];
+ png_composite_16(w, v, a, png_ptr->background_1.green);
+ if (optimize == 0)
+ w = gamma_16_from_1[((w & 0xff) >> gamma_shift)][w >>
+ 8];
+
+ *(sp + 2) = (png_byte)((w >> 8) & 0xff);
+ *(sp + 3) = (png_byte)(w & 0xff);
+
+ v = gamma_16_to_1[*(sp + 5) >> gamma_shift][*(sp + 4)];
+ png_composite_16(w, v, a, png_ptr->background_1.blue);
+ if (optimize == 0)
+ w = gamma_16_from_1[((w & 0xff) >> gamma_shift)][w >>
+ 8];
+
+ *(sp + 4) = (png_byte)((w >> 8) & 0xff);
+ *(sp + 5) = (png_byte)(w & 0xff);
+ }
+ }
+ }
+
+ else
+#endif
+ {
+ sp = row;
+ for (i = 0; i < row_width; i++, sp += 8)
+ {
+ png_uint_16 a = (png_uint_16)(((png_uint_16)(*(sp + 6))
+ << 8) + (png_uint_16)(*(sp + 7)));
+
+ if (a == 0)
+ {
+ *sp = (png_byte)((png_ptr->background.red >> 8) & 0xff);
+ *(sp + 1) = (png_byte)(png_ptr->background.red & 0xff);
+ *(sp + 2) = (png_byte)((png_ptr->background.green >> 8)
+ & 0xff);
+ *(sp + 3) = (png_byte)(png_ptr->background.green
+ & 0xff);
+ *(sp + 4) = (png_byte)((png_ptr->background.blue >> 8)
+ & 0xff);
+ *(sp + 5) = (png_byte)(png_ptr->background.blue & 0xff);
+ }
+
+ else if (a < 0xffff)
+ {
+ png_uint_16 v;
+
+ png_uint_16 r = (png_uint_16)(((*sp) << 8) + *(sp + 1));
+ png_uint_16 g = (png_uint_16)(((*(sp + 2)) << 8)
+ + *(sp + 3));
+ png_uint_16 b = (png_uint_16)(((*(sp + 4)) << 8)
+ + *(sp + 5));
+
+ png_composite_16(v, r, a, png_ptr->background.red);
+ *sp = (png_byte)((v >> 8) & 0xff);
+ *(sp + 1) = (png_byte)(v & 0xff);
+
+ png_composite_16(v, g, a, png_ptr->background.green);
+ *(sp + 2) = (png_byte)((v >> 8) & 0xff);
+ *(sp + 3) = (png_byte)(v & 0xff);
+
+ png_composite_16(v, b, a, png_ptr->background.blue);
+ *(sp + 4) = (png_byte)((v >> 8) & 0xff);
+ *(sp + 5) = (png_byte)(v & 0xff);
+ }
+ }
+ }
+ }
+ break;
+ }
+
+ default:
+ break;
+ }
+ }
+}
+#endif /* READ_BACKGROUND || READ_ALPHA_MODE */
+
+#ifdef PNG_READ_GAMMA_SUPPORTED
+/* Gamma correct the image, avoiding the alpha channel. Make sure
+ * you do this after you deal with the transparency issue on grayscale
+ * or RGB images. If your bit depth is 8, use gamma_table, if it
+ * is 16, use gamma_16_table and gamma_shift. Build these with
+ * build_gamma_table().
+ */
+static void
+png_do_gamma(png_row_infop row_info, png_bytep row, png_structrp png_ptr)
+{
+ png_const_bytep gamma_table = png_ptr->gamma_table;
+ png_const_uint_16pp gamma_16_table = png_ptr->gamma_16_table;
+ int gamma_shift = png_ptr->gamma_shift;
+
+ png_bytep sp;
+ png_uint_32 i;
+ png_uint_32 row_width=row_info->width;
+
+ png_debug(1, "in png_do_gamma");
+
+ if (((row_info->bit_depth <= 8 && gamma_table != NULL) ||
+ (row_info->bit_depth == 16 && gamma_16_table != NULL)))
+ {
+ switch (row_info->color_type)
+ {
+ case PNG_COLOR_TYPE_RGB:
+ {
+ if (row_info->bit_depth == 8)
+ {
+ sp = row;
+ for (i = 0; i < row_width; i++)
+ {
+ *sp = gamma_table[*sp];
+ sp++;
+ *sp = gamma_table[*sp];
+ sp++;
+ *sp = gamma_table[*sp];
+ sp++;
+ }
+ }
+
+ else /* if (row_info->bit_depth == 16) */
+ {
+ sp = row;
+ for (i = 0; i < row_width; i++)
+ {
+ png_uint_16 v;
+
+ v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
+ *sp = (png_byte)((v >> 8) & 0xff);
+ *(sp + 1) = (png_byte)(v & 0xff);
+ sp += 2;
+
+ v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
+ *sp = (png_byte)((v >> 8) & 0xff);
+ *(sp + 1) = (png_byte)(v & 0xff);
+ sp += 2;
+
+ v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
+ *sp = (png_byte)((v >> 8) & 0xff);
+ *(sp + 1) = (png_byte)(v & 0xff);
+ sp += 2;
+ }
+ }
+ break;
+ }
+
+ case PNG_COLOR_TYPE_RGB_ALPHA:
+ {
+ if (row_info->bit_depth == 8)
+ {
+ sp = row;
+ for (i = 0; i < row_width; i++)
+ {
+ *sp = gamma_table[*sp];
+ sp++;
+
+ *sp = gamma_table[*sp];
+ sp++;
+
+ *sp = gamma_table[*sp];
+ sp++;
+
+ sp++;
+ }
+ }
+
+ else /* if (row_info->bit_depth == 16) */
+ {
+ sp = row;
+ for (i = 0; i < row_width; i++)
+ {
+ png_uint_16 v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
+ *sp = (png_byte)((v >> 8) & 0xff);
+ *(sp + 1) = (png_byte)(v & 0xff);
+ sp += 2;
+
+ v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
+ *sp = (png_byte)((v >> 8) & 0xff);
+ *(sp + 1) = (png_byte)(v & 0xff);
+ sp += 2;
+
+ v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
+ *sp = (png_byte)((v >> 8) & 0xff);
+ *(sp + 1) = (png_byte)(v & 0xff);
+ sp += 4;
+ }
+ }
+ break;
+ }
+
+ case PNG_COLOR_TYPE_GRAY_ALPHA:
+ {
+ if (row_info->bit_depth == 8)
+ {
+ sp = row;
+ for (i = 0; i < row_width; i++)
+ {
+ *sp = gamma_table[*sp];
+ sp += 2;
+ }
+ }
+
+ else /* if (row_info->bit_depth == 16) */
+ {
+ sp = row;
+ for (i = 0; i < row_width; i++)
+ {
+ png_uint_16 v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
+ *sp = (png_byte)((v >> 8) & 0xff);
+ *(sp + 1) = (png_byte)(v & 0xff);
+ sp += 4;
+ }
+ }
+ break;
+ }
+
+ case PNG_COLOR_TYPE_GRAY:
+ {
+ if (row_info->bit_depth == 2)
+ {
+ sp = row;
+ for (i = 0; i < row_width; i += 4)
+ {
+ int a = *sp & 0xc0;
+ int b = *sp & 0x30;
+ int c = *sp & 0x0c;
+ int d = *sp & 0x03;
+
+ *sp = (png_byte)(
+ ((((int)gamma_table[a|(a>>2)|(a>>4)|(a>>6)]) ) & 0xc0)|
+ ((((int)gamma_table[(b<<2)|b|(b>>2)|(b>>4)])>>2) & 0x30)|
+ ((((int)gamma_table[(c<<4)|(c<<2)|c|(c>>2)])>>4) & 0x0c)|
+ ((((int)gamma_table[(d<<6)|(d<<4)|(d<<2)|d])>>6) ));
+ sp++;
+ }
+ }
+
+ if (row_info->bit_depth == 4)
+ {
+ sp = row;
+ for (i = 0; i < row_width; i += 2)
+ {
+ int msb = *sp & 0xf0;
+ int lsb = *sp & 0x0f;
+
+ *sp = (png_byte)((((int)gamma_table[msb | (msb >> 4)]) & 0xf0)
+ | (((int)gamma_table[(lsb << 4) | lsb]) >> 4));
+ sp++;
+ }
+ }
+
+ else if (row_info->bit_depth == 8)
+ {
+ sp = row;
+ for (i = 0; i < row_width; i++)
+ {
+ *sp = gamma_table[*sp];
+ sp++;
+ }
+ }
+
+ else if (row_info->bit_depth == 16)
+ {
+ sp = row;
+ for (i = 0; i < row_width; i++)
+ {
+ png_uint_16 v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
+ *sp = (png_byte)((v >> 8) & 0xff);
+ *(sp + 1) = (png_byte)(v & 0xff);
+ sp += 2;
+ }
+ }
+ break;
+ }
+
+ default:
+ break;
+ }
+ }
+}
+#endif
+
+#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
+/* Encode the alpha channel to the output gamma (the input channel is always
+ * linear.) Called only with color types that have an alpha channel. Needs the
+ * from_1 tables.
+ */
+static void
+png_do_encode_alpha(png_row_infop row_info, png_bytep row, png_structrp png_ptr)
+{
+ png_uint_32 row_width = row_info->width;
+
+ png_debug(1, "in png_do_encode_alpha");
+
+ if ((row_info->color_type & PNG_COLOR_MASK_ALPHA) != 0)
+ {
+ if (row_info->bit_depth == 8)
+ {
+ PNG_CONST png_bytep table = png_ptr->gamma_from_1;
+
+ if (table != NULL)
+ {
+ PNG_CONST int step =
+ (row_info->color_type & PNG_COLOR_MASK_COLOR) ? 4 : 2;
+
+ /* The alpha channel is the last component: */
+ row += step - 1;
+
+ for (; row_width > 0; --row_width, row += step)
+ *row = table[*row];
+
+ return;
+ }
+ }
+
+ else if (row_info->bit_depth == 16)
+ {
+ PNG_CONST png_uint_16pp table = png_ptr->gamma_16_from_1;
+ PNG_CONST int gamma_shift = png_ptr->gamma_shift;
+
+ if (table != NULL)
+ {
+ PNG_CONST int step =
+ (row_info->color_type & PNG_COLOR_MASK_COLOR) ? 8 : 4;
+
+ /* The alpha channel is the last component: */
+ row += step - 2;
+
+ for (; row_width > 0; --row_width, row += step)
+ {
+ png_uint_16 v;
+
+ v = table[*(row + 1) >> gamma_shift][*row];
+ *row = (png_byte)((v >> 8) & 0xff);
+ *(row + 1) = (png_byte)(v & 0xff);
+ }
+
+ return;
+ }
+ }
+ }
+
+ /* Only get to here if called with a weird row_info; no harm has been done,
+ * so just issue a warning.
+ */
+ png_warning(png_ptr, "png_do_encode_alpha: unexpected call");
+}
+#endif
+
+#ifdef PNG_READ_EXPAND_SUPPORTED
+/* Expands a palette row to an RGB or RGBA row depending
+ * upon whether you supply trans and num_trans.
+ */
+static void
+png_do_expand_palette(png_row_infop row_info, png_bytep row,
+ png_const_colorp palette, png_const_bytep trans_alpha, int num_trans)
+{
+ int shift, value;
+ png_bytep sp, dp;
+ png_uint_32 i;
+ png_uint_32 row_width=row_info->width;
+
+ png_debug(1, "in png_do_expand_palette");
+
+ if (row_info->color_type == PNG_COLOR_TYPE_PALETTE)
+ {
+ if (row_info->bit_depth < 8)
+ {
+ switch (row_info->bit_depth)
+ {
+ case 1:
+ {
+ sp = row + (png_size_t)((row_width - 1) >> 3);
+ dp = row + (png_size_t)row_width - 1;
+ shift = 7 - (int)((row_width + 7) & 0x07);
+ for (i = 0; i < row_width; i++)
+ {
+ if ((*sp >> shift) & 0x01)
+ *dp = 1;
+
+ else
+ *dp = 0;
+
+ if (shift == 7)
+ {
+ shift = 0;
+ sp--;
+ }
+
+ else
+ shift++;
+
+ dp--;
+ }
+ break;
+ }
+
+ case 2:
+ {
+ sp = row + (png_size_t)((row_width - 1) >> 2);
+ dp = row + (png_size_t)row_width - 1;
+ shift = (int)((3 - ((row_width + 3) & 0x03)) << 1);
+ for (i = 0; i < row_width; i++)
+ {
+ value = (*sp >> shift) & 0x03;
+ *dp = (png_byte)value;
+ if (shift == 6)
+ {
+ shift = 0;
+ sp--;
+ }
+
+ else
+ shift += 2;
+
+ dp--;
+ }
+ break;
+ }
+
+ case 4:
+ {
+ sp = row + (png_size_t)((row_width - 1) >> 1);
+ dp = row + (png_size_t)row_width - 1;
+ shift = (int)((row_width & 0x01) << 2);
+ for (i = 0; i < row_width; i++)
+ {
+ value = (*sp >> shift) & 0x0f;
+ *dp = (png_byte)value;
+ if (shift == 4)
+ {
+ shift = 0;
+ sp--;
+ }
+
+ else
+ shift += 4;
+
+ dp--;
+ }
+ break;
+ }
+
+ default:
+ break;
+ }
+ row_info->bit_depth = 8;
+ row_info->pixel_depth = 8;
+ row_info->rowbytes = row_width;
+ }
+
+ if (row_info->bit_depth == 8)
+ {
+ {
+ if (num_trans > 0)
+ {
+ sp = row + (png_size_t)row_width - 1;
+ dp = row + (png_size_t)(row_width << 2) - 1;
+
+ for (i = 0; i < row_width; i++)
+ {
+ if ((int)(*sp) >= num_trans)
+ *dp-- = 0xff;
+
+ else
+ *dp-- = trans_alpha[*sp];
+
+ *dp-- = palette[*sp].blue;
+ *dp-- = palette[*sp].green;
+ *dp-- = palette[*sp].red;
+ sp--;
+ }
+ row_info->bit_depth = 8;
+ row_info->pixel_depth = 32;
+ row_info->rowbytes = row_width * 4;
+ row_info->color_type = 6;
+ row_info->channels = 4;
+ }
+
+ else
+ {
+ sp = row + (png_size_t)row_width - 1;
+ dp = row + (png_size_t)(row_width * 3) - 1;
+
+ for (i = 0; i < row_width; i++)
+ {
+ *dp-- = palette[*sp].blue;
+ *dp-- = palette[*sp].green;
+ *dp-- = palette[*sp].red;
+ sp--;
+ }
+
+ row_info->bit_depth = 8;
+ row_info->pixel_depth = 24;
+ row_info->rowbytes = row_width * 3;
+ row_info->color_type = 2;
+ row_info->channels = 3;
+ }
+ }
+ }
+ }
+}
+
+/* If the bit depth < 8, it is expanded to 8. Also, if the already
+ * expanded transparency value is supplied, an alpha channel is built.
+ */
+static void
+png_do_expand(png_row_infop row_info, png_bytep row,
+ png_const_color_16p trans_color)
+{
+ int shift, value;
+ png_bytep sp, dp;
+ png_uint_32 i;
+ png_uint_32 row_width=row_info->width;
+
+ png_debug(1, "in png_do_expand");
+
+ {
+ if (row_info->color_type == PNG_COLOR_TYPE_GRAY)
+ {
+ unsigned int gray = trans_color != NULL ? trans_color->gray : 0;
+
+ if (row_info->bit_depth < 8)
+ {
+ switch (row_info->bit_depth)
+ {
+ case 1:
+ {
+ gray = (gray & 0x01) * 0xff;
+ sp = row + (png_size_t)((row_width - 1) >> 3);
+ dp = row + (png_size_t)row_width - 1;
+ shift = 7 - (int)((row_width + 7) & 0x07);
+ for (i = 0; i < row_width; i++)
+ {
+ if ((*sp >> shift) & 0x01)
+ *dp = 0xff;
+
+ else
+ *dp = 0;
+
+ if (shift == 7)
+ {
+ shift = 0;
+ sp--;
+ }
+
+ else
+ shift++;
+
+ dp--;
+ }
+ break;
+ }
+
+ case 2:
+ {
+ gray = (gray & 0x03) * 0x55;
+ sp = row + (png_size_t)((row_width - 1) >> 2);
+ dp = row + (png_size_t)row_width - 1;
+ shift = (int)((3 - ((row_width + 3) & 0x03)) << 1);
+ for (i = 0; i < row_width; i++)
+ {
+ value = (*sp >> shift) & 0x03;
+ *dp = (png_byte)(value | (value << 2) | (value << 4) |
+ (value << 6));
+ if (shift == 6)
+ {
+ shift = 0;
+ sp--;
+ }
+
+ else
+ shift += 2;
+
+ dp--;
+ }
+ break;
+ }
+
+ case 4:
+ {
+ gray = (gray & 0x0f) * 0x11;
+ sp = row + (png_size_t)((row_width - 1) >> 1);
+ dp = row + (png_size_t)row_width - 1;
+ shift = (int)((1 - ((row_width + 1) & 0x01)) << 2);
+ for (i = 0; i < row_width; i++)
+ {
+ value = (*sp >> shift) & 0x0f;
+ *dp = (png_byte)(value | (value << 4));
+ if (shift == 4)
+ {
+ shift = 0;
+ sp--;
+ }
+
+ else
+ shift = 4;
+
+ dp--;
+ }
+ break;
+ }
+
+ default:
+ break;
+ }
+
+ row_info->bit_depth = 8;
+ row_info->pixel_depth = 8;
+ row_info->rowbytes = row_width;
+ }
+
+ if (trans_color != NULL)
+ {
+ if (row_info->bit_depth == 8)
+ {
+ gray = gray & 0xff;
+ sp = row + (png_size_t)row_width - 1;
+ dp = row + (png_size_t)(row_width << 1) - 1;
+
+ for (i = 0; i < row_width; i++)
+ {
+ if (*sp == gray)
+ *dp-- = 0;
+
+ else
+ *dp-- = 0xff;
+
+ *dp-- = *sp--;
+ }
+ }
+
+ else if (row_info->bit_depth == 16)
+ {
+ unsigned int gray_high = (gray >> 8) & 0xff;
+ unsigned int gray_low = gray & 0xff;
+ sp = row + row_info->rowbytes - 1;
+ dp = row + (row_info->rowbytes << 1) - 1;
+ for (i = 0; i < row_width; i++)
+ {
+ if (*(sp - 1) == gray_high && *(sp) == gray_low)
+ {
+ *dp-- = 0;
+ *dp-- = 0;
+ }
+
+ else
+ {
+ *dp-- = 0xff;
+ *dp-- = 0xff;
+ }
+
+ *dp-- = *sp--;
+ *dp-- = *sp--;
+ }
+ }
+
+ row_info->color_type = PNG_COLOR_TYPE_GRAY_ALPHA;
+ row_info->channels = 2;
+ row_info->pixel_depth = (png_byte)(row_info->bit_depth << 1);
+ row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth,
+ row_width);
+ }
+ }
+ else if (row_info->color_type == PNG_COLOR_TYPE_RGB &&
+ trans_color != NULL)
+ {
+ if (row_info->bit_depth == 8)
+ {
+ png_byte red = (png_byte)(trans_color->red & 0xff);
+ png_byte green = (png_byte)(trans_color->green & 0xff);
+ png_byte blue = (png_byte)(trans_color->blue & 0xff);
+ sp = row + (png_size_t)row_info->rowbytes - 1;
+ dp = row + (png_size_t)(row_width << 2) - 1;
+ for (i = 0; i < row_width; i++)
+ {
+ if (*(sp - 2) == red && *(sp - 1) == green && *(sp) == blue)
+ *dp-- = 0;
+
+ else
+ *dp-- = 0xff;
+
+ *dp-- = *sp--;
+ *dp-- = *sp--;
+ *dp-- = *sp--;
+ }
+ }
+ else if (row_info->bit_depth == 16)
+ {
+ png_byte red_high = (png_byte)((trans_color->red >> 8) & 0xff);
+ png_byte green_high = (png_byte)((trans_color->green >> 8) & 0xff);
+ png_byte blue_high = (png_byte)((trans_color->blue >> 8) & 0xff);
+ png_byte red_low = (png_byte)(trans_color->red & 0xff);
+ png_byte green_low = (png_byte)(trans_color->green & 0xff);
+ png_byte blue_low = (png_byte)(trans_color->blue & 0xff);
+ sp = row + row_info->rowbytes - 1;
+ dp = row + (png_size_t)(row_width << 3) - 1;
+ for (i = 0; i < row_width; i++)
+ {
+ if (*(sp - 5) == red_high &&
+ *(sp - 4) == red_low &&
+ *(sp - 3) == green_high &&
+ *(sp - 2) == green_low &&
+ *(sp - 1) == blue_high &&
+ *(sp ) == blue_low)
+ {
+ *dp-- = 0;
+ *dp-- = 0;
+ }
+
+ else
+ {
+ *dp-- = 0xff;
+ *dp-- = 0xff;
+ }
+
+ *dp-- = *sp--;
+ *dp-- = *sp--;
+ *dp-- = *sp--;
+ *dp-- = *sp--;
+ *dp-- = *sp--;
+ *dp-- = *sp--;
+ }
+ }
+ row_info->color_type = PNG_COLOR_TYPE_RGB_ALPHA;
+ row_info->channels = 4;
+ row_info->pixel_depth = (png_byte)(row_info->bit_depth << 2);
+ row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_width);
+ }
+ }
+}
+#endif
+
+#ifdef PNG_READ_EXPAND_16_SUPPORTED
+/* If the bit depth is 8 and the color type is not a palette type expand the
+ * whole row to 16 bits. Has no effect otherwise.
+ */
+static void
+png_do_expand_16(png_row_infop row_info, png_bytep row)
+{
+ if (row_info->bit_depth == 8 &&
+ row_info->color_type != PNG_COLOR_TYPE_PALETTE)
+ {
+ /* The row have a sequence of bytes containing [0..255] and we need
+ * to turn it into another row containing [0..65535], to do this we
+ * calculate:
+ *
+ * (input / 255) * 65535
+ *
+ * Which happens to be exactly input * 257 and this can be achieved
+ * simply by byte replication in place (copying backwards).
+ */
+ png_byte *sp = row + row_info->rowbytes; /* source, last byte + 1 */
+ png_byte *dp = sp + row_info->rowbytes; /* destination, end + 1 */
+ while (dp > sp)
+ dp[-2] = dp[-1] = *--sp, dp -= 2;
+
+ row_info->rowbytes *= 2;
+ row_info->bit_depth = 16;
+ row_info->pixel_depth = (png_byte)(row_info->channels * 16);
+ }
+}
+#endif
+
+#ifdef PNG_READ_QUANTIZE_SUPPORTED
+static void
+png_do_quantize(png_row_infop row_info, png_bytep row,
+ png_const_bytep palette_lookup, png_const_bytep quantize_lookup)
+{
+ png_bytep sp, dp;
+ png_uint_32 i;
+ png_uint_32 row_width=row_info->width;
+
+ png_debug(1, "in png_do_quantize");
+
+ if (row_info->bit_depth == 8)
+ {
+ if (row_info->color_type == PNG_COLOR_TYPE_RGB && palette_lookup)
+ {
+ int r, g, b, p;
+ sp = row;
+ dp = row;
+ for (i = 0; i < row_width; i++)
+ {
+ r = *sp++;
+ g = *sp++;
+ b = *sp++;
+
+ /* This looks real messy, but the compiler will reduce
+ * it down to a reasonable formula. For example, with
+ * 5 bits per color, we get:
+ * p = (((r >> 3) & 0x1f) << 10) |
+ * (((g >> 3) & 0x1f) << 5) |
+ * ((b >> 3) & 0x1f);
+ */
+ p = (((r >> (8 - PNG_QUANTIZE_RED_BITS)) &
+ ((1 << PNG_QUANTIZE_RED_BITS) - 1)) <<
+ (PNG_QUANTIZE_GREEN_BITS + PNG_QUANTIZE_BLUE_BITS)) |
+ (((g >> (8 - PNG_QUANTIZE_GREEN_BITS)) &
+ ((1 << PNG_QUANTIZE_GREEN_BITS) - 1)) <<
+ (PNG_QUANTIZE_BLUE_BITS)) |
+ ((b >> (8 - PNG_QUANTIZE_BLUE_BITS)) &
+ ((1 << PNG_QUANTIZE_BLUE_BITS) - 1));
+
+ *dp++ = palette_lookup[p];
+ }
+
+ row_info->color_type = PNG_COLOR_TYPE_PALETTE;
+ row_info->channels = 1;
+ row_info->pixel_depth = row_info->bit_depth;
+ row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_width);
+ }
+
+ else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA &&
+ palette_lookup != NULL)
+ {
+ int r, g, b, p;
+ sp = row;
+ dp = row;
+ for (i = 0; i < row_width; i++)
+ {
+ r = *sp++;
+ g = *sp++;
+ b = *sp++;
+ sp++;
+
+ p = (((r >> (8 - PNG_QUANTIZE_RED_BITS)) &
+ ((1 << PNG_QUANTIZE_RED_BITS) - 1)) <<
+ (PNG_QUANTIZE_GREEN_BITS + PNG_QUANTIZE_BLUE_BITS)) |
+ (((g >> (8 - PNG_QUANTIZE_GREEN_BITS)) &
+ ((1 << PNG_QUANTIZE_GREEN_BITS) - 1)) <<
+ (PNG_QUANTIZE_BLUE_BITS)) |
+ ((b >> (8 - PNG_QUANTIZE_BLUE_BITS)) &
+ ((1 << PNG_QUANTIZE_BLUE_BITS) - 1));
+
+ *dp++ = palette_lookup[p];
+ }
+
+ row_info->color_type = PNG_COLOR_TYPE_PALETTE;
+ row_info->channels = 1;
+ row_info->pixel_depth = row_info->bit_depth;
+ row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_width);
+ }
+
+ else if (row_info->color_type == PNG_COLOR_TYPE_PALETTE &&
+ quantize_lookup)
+ {
+ sp = row;
+
+ for (i = 0; i < row_width; i++, sp++)
+ {
+ *sp = quantize_lookup[*sp];
+ }
+ }
+ }
+}
+#endif /* READ_QUANTIZE */
+
+/* Transform the row. The order of transformations is significant,
+ * and is very touchy. If you add a transformation, take care to
+ * decide how it fits in with the other transformations here.
+ */
+void /* PRIVATE */
+png_do_read_transformations(png_structrp png_ptr, png_row_infop row_info)
+{
+ png_debug(1, "in png_do_read_transformations");
+
+ if (png_ptr->row_buf == NULL)
+ {
+ /* Prior to 1.5.4 this output row/pass where the NULL pointer is, but this
+ * error is incredibly rare and incredibly easy to debug without this
+ * information.
+ */
+ png_error(png_ptr, "NULL row buffer");
+ }
+
+ /* The following is debugging; prior to 1.5.4 the code was never compiled in;
+ * in 1.5.4 PNG_FLAG_DETECT_UNINITIALIZED was added and the macro
+ * PNG_WARN_UNINITIALIZED_ROW removed. In 1.6 the new flag is set only for
+ * all transformations, however in practice the ROW_INIT always gets done on
+ * demand, if necessary.
+ */
+ if ((png_ptr->flags & PNG_FLAG_DETECT_UNINITIALIZED) != 0 &&
+ (png_ptr->flags & PNG_FLAG_ROW_INIT) == 0)
+ {
+ /* Application has failed to call either png_read_start_image() or
+ * png_read_update_info() after setting transforms that expand pixels.
+ * This check added to libpng-1.2.19 (but not enabled until 1.5.4).
+ */
+ png_error(png_ptr, "Uninitialized row");
+ }
+
+#ifdef PNG_READ_EXPAND_SUPPORTED
+ if ((png_ptr->transformations & PNG_EXPAND) != 0)
+ {
+ if (row_info->color_type == PNG_COLOR_TYPE_PALETTE)
+ {
+ png_do_expand_palette(row_info, png_ptr->row_buf + 1,
+ png_ptr->palette, png_ptr->trans_alpha, png_ptr->num_trans);
+ }
+
+ else
+ {
+ if (png_ptr->num_trans != 0 &&
+ (png_ptr->transformations & PNG_EXPAND_tRNS) != 0)
+ png_do_expand(row_info, png_ptr->row_buf + 1,
+ &(png_ptr->trans_color));
+
+ else
+ png_do_expand(row_info, png_ptr->row_buf + 1,
+ NULL);
+ }
+ }
+#endif
+
+#ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
+ if ((png_ptr->transformations & PNG_STRIP_ALPHA) != 0 &&
+ (png_ptr->transformations & PNG_COMPOSE) == 0 &&
+ (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA ||
+ row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA))
+ png_do_strip_channel(row_info, png_ptr->row_buf + 1,
+ 0 /* at_start == false, because SWAP_ALPHA happens later */);
+#endif
+
+#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
+ if ((png_ptr->transformations & PNG_RGB_TO_GRAY) != 0)
+ {
+ int rgb_error =
+ png_do_rgb_to_gray(png_ptr, row_info,
+ png_ptr->row_buf + 1);
+
+ if (rgb_error != 0)
+ {
+ png_ptr->rgb_to_gray_status=1;
+ if ((png_ptr->transformations & PNG_RGB_TO_GRAY) ==
+ PNG_RGB_TO_GRAY_WARN)
+ png_warning(png_ptr, "png_do_rgb_to_gray found nongray pixel");
+
+ if ((png_ptr->transformations & PNG_RGB_TO_GRAY) ==
+ PNG_RGB_TO_GRAY_ERR)
+ png_error(png_ptr, "png_do_rgb_to_gray found nongray pixel");
+ }
+ }
+#endif
+
+/* From Andreas Dilger e-mail to png-implement, 26 March 1998:
+ *
+ * In most cases, the "simple transparency" should be done prior to doing
+ * gray-to-RGB, or you will have to test 3x as many bytes to check if a
+ * pixel is transparent. You would also need to make sure that the
+ * transparency information is upgraded to RGB.
+ *
+ * To summarize, the current flow is:
+ * - Gray + simple transparency -> compare 1 or 2 gray bytes and composite
+ * with background "in place" if transparent,
+ * convert to RGB if necessary
+ * - Gray + alpha -> composite with gray background and remove alpha bytes,
+ * convert to RGB if necessary
+ *
+ * To support RGB backgrounds for gray images we need:
+ * - Gray + simple transparency -> convert to RGB + simple transparency,
+ * compare 3 or 6 bytes and composite with
+ * background "in place" if transparent
+ * (3x compare/pixel compared to doing
+ * composite with gray bkgrnd)
+ * - Gray + alpha -> convert to RGB + alpha, composite with background and
+ * remove alpha bytes (3x float
+ * operations/pixel compared with composite
+ * on gray background)
+ *
+ * Greg's change will do this. The reason it wasn't done before is for
+ * performance, as this increases the per-pixel operations. If we would check
+ * in advance if the background was gray or RGB, and position the gray-to-RGB
+ * transform appropriately, then it would save a lot of work/time.
+ */
+
+#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
+ /* If gray -> RGB, do so now only if background is non-gray; else do later
+ * for performance reasons
+ */
+ if ((png_ptr->transformations & PNG_GRAY_TO_RGB) != 0 &&
+ (png_ptr->mode & PNG_BACKGROUND_IS_GRAY) == 0)
+ png_do_gray_to_rgb(row_info, png_ptr->row_buf + 1);
+#endif
+
+#if defined(PNG_READ_BACKGROUND_SUPPORTED) ||\
+ defined(PNG_READ_ALPHA_MODE_SUPPORTED)
+ if ((png_ptr->transformations & PNG_COMPOSE) != 0)
+ png_do_compose(row_info, png_ptr->row_buf + 1, png_ptr);
+#endif
+
+#ifdef PNG_READ_GAMMA_SUPPORTED
+ if ((png_ptr->transformations & PNG_GAMMA) != 0 &&
+#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
+ /* Because RGB_TO_GRAY does the gamma transform. */
+ (png_ptr->transformations & PNG_RGB_TO_GRAY) == 0 &&
+#endif
+#if defined(PNG_READ_BACKGROUND_SUPPORTED) ||\
+ defined(PNG_READ_ALPHA_MODE_SUPPORTED)
+ /* Because PNG_COMPOSE does the gamma transform if there is something to
+ * do (if there is an alpha channel or transparency.)
+ */
+ !((png_ptr->transformations & PNG_COMPOSE) != 0 &&
+ ((png_ptr->num_trans != 0) ||
+ (png_ptr->color_type & PNG_COLOR_MASK_ALPHA) != 0)) &&
+#endif
+ /* Because png_init_read_transformations transforms the palette, unless
+ * RGB_TO_GRAY will do the transform.
+ */
+ (png_ptr->color_type != PNG_COLOR_TYPE_PALETTE))
+ png_do_gamma(row_info, png_ptr->row_buf + 1, png_ptr);
+#endif
+
+#ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
+ if ((png_ptr->transformations & PNG_STRIP_ALPHA) != 0 &&
+ (png_ptr->transformations & PNG_COMPOSE) != 0 &&
+ (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA ||
+ row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA))
+ png_do_strip_channel(row_info, png_ptr->row_buf + 1,
+ 0 /* at_start == false, because SWAP_ALPHA happens later */);
+#endif
+
+#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
+ if ((png_ptr->transformations & PNG_ENCODE_ALPHA) != 0 &&
+ (row_info->color_type & PNG_COLOR_MASK_ALPHA) != 0)
+ png_do_encode_alpha(row_info, png_ptr->row_buf + 1, png_ptr);
+#endif
+
+#ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
+ if ((png_ptr->transformations & PNG_SCALE_16_TO_8) != 0)
+ png_do_scale_16_to_8(row_info, png_ptr->row_buf + 1);
+#endif
+
+#ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
+ /* There is no harm in doing both of these because only one has any effect,
+ * by putting the 'scale' option first if the app asks for scale (either by
+ * calling the API or in a TRANSFORM flag) this is what happens.
+ */
+ if ((png_ptr->transformations & PNG_16_TO_8) != 0)
+ png_do_chop(row_info, png_ptr->row_buf + 1);
+#endif
+
+#ifdef PNG_READ_QUANTIZE_SUPPORTED
+ if ((png_ptr->transformations & PNG_QUANTIZE) != 0)
+ {
+ png_do_quantize(row_info, png_ptr->row_buf + 1,
+ png_ptr->palette_lookup, png_ptr->quantize_index);
+
+ if (row_info->rowbytes == 0)
+ png_error(png_ptr, "png_do_quantize returned rowbytes=0");
+ }
+#endif /* READ_QUANTIZE */
+
+#ifdef PNG_READ_EXPAND_16_SUPPORTED
+ /* Do the expansion now, after all the arithmetic has been done. Notice
+ * that previous transformations can handle the PNG_EXPAND_16 flag if this
+ * is efficient (particularly true in the case of gamma correction, where
+ * better accuracy results faster!)
+ */
+ if ((png_ptr->transformations & PNG_EXPAND_16) != 0)
+ png_do_expand_16(row_info, png_ptr->row_buf + 1);
+#endif
+
+#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
+ /* NOTE: moved here in 1.5.4 (from much later in this list.) */
+ if ((png_ptr->transformations & PNG_GRAY_TO_RGB) != 0 &&
+ (png_ptr->mode & PNG_BACKGROUND_IS_GRAY) != 0)
+ png_do_gray_to_rgb(row_info, png_ptr->row_buf + 1);
+#endif
+
+#ifdef PNG_READ_INVERT_SUPPORTED
+ if ((png_ptr->transformations & PNG_INVERT_MONO) != 0)
+ png_do_invert(row_info, png_ptr->row_buf + 1);
+#endif
+
+#ifdef PNG_READ_INVERT_ALPHA_SUPPORTED
+ if ((png_ptr->transformations & PNG_INVERT_ALPHA) != 0)
+ png_do_read_invert_alpha(row_info, png_ptr->row_buf + 1);
+#endif
+
+#ifdef PNG_READ_SHIFT_SUPPORTED
+ if ((png_ptr->transformations & PNG_SHIFT) != 0)
+ png_do_unshift(row_info, png_ptr->row_buf + 1,
+ &(png_ptr->shift));
+#endif
+
+#ifdef PNG_READ_PACK_SUPPORTED
+ if ((png_ptr->transformations & PNG_PACK) != 0)
+ png_do_unpack(row_info, png_ptr->row_buf + 1);
+#endif
+
+#ifdef PNG_READ_CHECK_FOR_INVALID_INDEX_SUPPORTED
+ /* Added at libpng-1.5.10 */
+ if (row_info->color_type == PNG_COLOR_TYPE_PALETTE &&
+ png_ptr->num_palette_max >= 0)
+ png_do_check_palette_indexes(png_ptr, row_info);
+#endif
+
+#ifdef PNG_READ_BGR_SUPPORTED
+ if ((png_ptr->transformations & PNG_BGR) != 0)
+ png_do_bgr(row_info, png_ptr->row_buf + 1);
+#endif
+
+#ifdef PNG_READ_PACKSWAP_SUPPORTED
+ if ((png_ptr->transformations & PNG_PACKSWAP) != 0)
+ png_do_packswap(row_info, png_ptr->row_buf + 1);
+#endif
+
+#ifdef PNG_READ_FILLER_SUPPORTED
+ if ((png_ptr->transformations & PNG_FILLER) != 0)
+ png_do_read_filler(row_info, png_ptr->row_buf + 1,
+ (png_uint_32)png_ptr->filler, png_ptr->flags);
+#endif
+
+#ifdef PNG_READ_SWAP_ALPHA_SUPPORTED
+ if ((png_ptr->transformations & PNG_SWAP_ALPHA) != 0)
+ png_do_read_swap_alpha(row_info, png_ptr->row_buf + 1);
+#endif
+
+#ifdef PNG_READ_16BIT_SUPPORTED
+#ifdef PNG_READ_SWAP_SUPPORTED
+ if ((png_ptr->transformations & PNG_SWAP_BYTES) != 0)
+ png_do_swap(row_info, png_ptr->row_buf + 1);
+#endif
+#endif
+
+#ifdef PNG_READ_USER_TRANSFORM_SUPPORTED
+ if ((png_ptr->transformations & PNG_USER_TRANSFORM) != 0)
+ {
+ if (png_ptr->read_user_transform_fn != NULL)
+ (*(png_ptr->read_user_transform_fn)) /* User read transform function */
+ (png_ptr, /* png_ptr */
+ row_info, /* row_info: */
+ /* png_uint_32 width; width of row */
+ /* png_size_t rowbytes; number of bytes in row */
+ /* png_byte color_type; color type of pixels */
+ /* png_byte bit_depth; bit depth of samples */
+ /* png_byte channels; number of channels (1-4) */
+ /* png_byte pixel_depth; bits per pixel (depth*channels) */
+ png_ptr->row_buf + 1); /* start of pixel data for row */
+#ifdef PNG_USER_TRANSFORM_PTR_SUPPORTED
+ if (png_ptr->user_transform_depth != 0)
+ row_info->bit_depth = png_ptr->user_transform_depth;
+
+ if (png_ptr->user_transform_channels != 0)
+ row_info->channels = png_ptr->user_transform_channels;
+#endif
+ row_info->pixel_depth = (png_byte)(row_info->bit_depth *
+ row_info->channels);
+
+ row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_info->width);
+ }
+#endif
+}
+
+#endif /* READ_TRANSFORMS */
+#endif /* READ */
--- /dev/null
+
+/* pngrutil.c - utilities to read a PNG file
+ *
+ * Last changed in libpng 1.6.17 [March 26, 2015]
+ * Copyright (c) 1998-2015 Glenn Randers-Pehrson
+ * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
+ * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ *
+ * This file contains routines that are only called from within
+ * libpng itself during the course of reading an image.
+ */
+
+#include "pngpriv.h"
+
+#ifdef PNG_READ_SUPPORTED
+
+png_uint_32 PNGAPI
+png_get_uint_31(png_const_structrp png_ptr, png_const_bytep buf)
+{
+ png_uint_32 uval = png_get_uint_32(buf);
+
+ if (uval > PNG_UINT_31_MAX)
+ png_error(png_ptr, "PNG unsigned integer out of range");
+
+ return (uval);
+}
+
+#if defined(PNG_READ_gAMA_SUPPORTED) || defined(PNG_READ_cHRM_SUPPORTED)
+/* The following is a variation on the above for use with the fixed
+ * point values used for gAMA and cHRM. Instead of png_error it
+ * issues a warning and returns (-1) - an invalid value because both
+ * gAMA and cHRM use *unsigned* integers for fixed point values.
+ */
+#define PNG_FIXED_ERROR (-1)
+
+static png_fixed_point /* PRIVATE */
+png_get_fixed_point(png_structrp png_ptr, png_const_bytep buf)
+{
+ png_uint_32 uval = png_get_uint_32(buf);
+
+ if (uval <= PNG_UINT_31_MAX)
+ return (png_fixed_point)uval; /* known to be in range */
+
+ /* The caller can turn off the warning by passing NULL. */
+ if (png_ptr != NULL)
+ png_warning(png_ptr, "PNG fixed point integer out of range");
+
+ return PNG_FIXED_ERROR;
+}
+#endif
+
+#ifdef PNG_READ_INT_FUNCTIONS_SUPPORTED
+/* NOTE: the read macros will obscure these definitions, so that if
+ * PNG_USE_READ_MACROS is set the library will not use them internally,
+ * but the APIs will still be available externally.
+ *
+ * The parentheses around "PNGAPI function_name" in the following three
+ * functions are necessary because they allow the macros to co-exist with
+ * these (unused but exported) functions.
+ */
+
+/* Grab an unsigned 32-bit integer from a buffer in big-endian format. */
+png_uint_32 (PNGAPI
+png_get_uint_32)(png_const_bytep buf)
+{
+ png_uint_32 uval =
+ ((png_uint_32)(*(buf )) << 24) +
+ ((png_uint_32)(*(buf + 1)) << 16) +
+ ((png_uint_32)(*(buf + 2)) << 8) +
+ ((png_uint_32)(*(buf + 3)) ) ;
+
+ return uval;
+}
+
+/* Grab a signed 32-bit integer from a buffer in big-endian format. The
+ * data is stored in the PNG file in two's complement format and there
+ * is no guarantee that a 'png_int_32' is exactly 32 bits, therefore
+ * the following code does a two's complement to native conversion.
+ */
+png_int_32 (PNGAPI
+png_get_int_32)(png_const_bytep buf)
+{
+ png_uint_32 uval = png_get_uint_32(buf);
+ if ((uval & 0x80000000) == 0) /* non-negative */
+ return uval;
+
+ uval = (uval ^ 0xffffffff) + 1; /* 2's complement: -x = ~x+1 */
+ return -(png_int_32)uval;
+}
+
+/* Grab an unsigned 16-bit integer from a buffer in big-endian format. */
+png_uint_16 (PNGAPI
+png_get_uint_16)(png_const_bytep buf)
+{
+ /* ANSI-C requires an int value to accomodate at least 16 bits so this
+ * works and allows the compiler not to worry about possible narrowing
+ * on 32 bit systems. (Pre-ANSI systems did not make integers smaller
+ * than 16 bits either.)
+ */
+ unsigned int val =
+ ((unsigned int)(*buf) << 8) +
+ ((unsigned int)(*(buf + 1)));
+
+ return (png_uint_16)val;
+}
+
+#endif /* READ_INT_FUNCTIONS */
+
+/* Read and check the PNG file signature */
+void /* PRIVATE */
+png_read_sig(png_structrp png_ptr, png_inforp info_ptr)
+{
+ png_size_t num_checked, num_to_check;
+
+ /* Exit if the user application does not expect a signature. */
+ if (png_ptr->sig_bytes >= 8)
+ return;
+
+ num_checked = png_ptr->sig_bytes;
+ num_to_check = 8 - num_checked;
+
+#ifdef PNG_IO_STATE_SUPPORTED
+ png_ptr->io_state = PNG_IO_READING | PNG_IO_SIGNATURE;
+#endif
+
+ /* The signature must be serialized in a single I/O call. */
+ png_read_data(png_ptr, &(info_ptr->signature[num_checked]), num_to_check);
+ png_ptr->sig_bytes = 8;
+
+ if (png_sig_cmp(info_ptr->signature, num_checked, num_to_check) != 0)
+ {
+ if (num_checked < 4 &&
+ png_sig_cmp(info_ptr->signature, num_checked, num_to_check - 4))
+ png_error(png_ptr, "Not a PNG file");
+ else
+ png_error(png_ptr, "PNG file corrupted by ASCII conversion");
+ }
+ if (num_checked < 3)
+ png_ptr->mode |= PNG_HAVE_PNG_SIGNATURE;
+}
+
+/* Read the chunk header (length + type name).
+ * Put the type name into png_ptr->chunk_name, and return the length.
+ */
+png_uint_32 /* PRIVATE */
+png_read_chunk_header(png_structrp png_ptr)
+{
+ png_byte buf[8];
+ png_uint_32 length;
+
+#ifdef PNG_IO_STATE_SUPPORTED
+ png_ptr->io_state = PNG_IO_READING | PNG_IO_CHUNK_HDR;
+#endif
+
+ /* Read the length and the chunk name.
+ * This must be performed in a single I/O call.
+ */
+ png_read_data(png_ptr, buf, 8);
+ length = png_get_uint_31(png_ptr, buf);
+
+ /* Put the chunk name into png_ptr->chunk_name. */
+ png_ptr->chunk_name = PNG_CHUNK_FROM_STRING(buf+4);
+
+ png_debug2(0, "Reading %lx chunk, length = %lu",
+ (unsigned long)png_ptr->chunk_name, (unsigned long)length);
+
+ /* Reset the crc and run it over the chunk name. */
+ png_reset_crc(png_ptr);
+ png_calculate_crc(png_ptr, buf + 4, 4);
+
+ /* Check to see if chunk name is valid. */
+ png_check_chunk_name(png_ptr, png_ptr->chunk_name);
+
+#ifdef PNG_IO_STATE_SUPPORTED
+ png_ptr->io_state = PNG_IO_READING | PNG_IO_CHUNK_DATA;
+#endif
+
+ return length;
+}
+
+/* Read data, and (optionally) run it through the CRC. */
+void /* PRIVATE */
+png_crc_read(png_structrp png_ptr, png_bytep buf, png_uint_32 length)
+{
+ if (png_ptr == NULL)
+ return;
+
+ png_read_data(png_ptr, buf, length);
+ png_calculate_crc(png_ptr, buf, length);
+}
+
+/* Optionally skip data and then check the CRC. Depending on whether we
+ * are reading an ancillary or critical chunk, and how the program has set
+ * things up, we may calculate the CRC on the data and print a message.
+ * Returns '1' if there was a CRC error, '0' otherwise.
+ */
+int /* PRIVATE */
+png_crc_finish(png_structrp png_ptr, png_uint_32 skip)
+{
+ /* The size of the local buffer for inflate is a good guess as to a
+ * reasonable size to use for buffering reads from the application.
+ */
+ while (skip > 0)
+ {
+ png_uint_32 len;
+ png_byte tmpbuf[PNG_INFLATE_BUF_SIZE];
+
+ len = (sizeof tmpbuf);
+ if (len > skip)
+ len = skip;
+ skip -= len;
+
+ png_crc_read(png_ptr, tmpbuf, len);
+ }
+
+ if (png_crc_error(png_ptr) != 0)
+ {
+ if (PNG_CHUNK_ANCILLARY(png_ptr->chunk_name) != 0 ?
+ (png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_NOWARN) == 0 :
+ (png_ptr->flags & PNG_FLAG_CRC_CRITICAL_USE) != 0)
+ {
+ png_chunk_warning(png_ptr, "CRC error");
+ }
+
+ else
+ png_chunk_error(png_ptr, "CRC error");
+
+ return (1);
+ }
+
+ return (0);
+}
+
+/* Compare the CRC stored in the PNG file with that calculated by libpng from
+ * the data it has read thus far.
+ */
+int /* PRIVATE */
+png_crc_error(png_structrp png_ptr)
+{
+ png_byte crc_bytes[4];
+ png_uint_32 crc;
+ int need_crc = 1;
+
+ if (PNG_CHUNK_ANCILLARY(png_ptr->chunk_name) != 0)
+ {
+ if ((png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_MASK) ==
+ (PNG_FLAG_CRC_ANCILLARY_USE | PNG_FLAG_CRC_ANCILLARY_NOWARN))
+ need_crc = 0;
+ }
+
+ else /* critical */
+ {
+ if ((png_ptr->flags & PNG_FLAG_CRC_CRITICAL_IGNORE) != 0)
+ need_crc = 0;
+ }
+
+#ifdef PNG_IO_STATE_SUPPORTED
+ png_ptr->io_state = PNG_IO_READING | PNG_IO_CHUNK_CRC;
+#endif
+
+ /* The chunk CRC must be serialized in a single I/O call. */
+ png_read_data(png_ptr, crc_bytes, 4);
+
+ if (need_crc != 0)
+ {
+ crc = png_get_uint_32(crc_bytes);
+ return ((int)(crc != png_ptr->crc));
+ }
+
+ else
+ return (0);
+}
+
+#if defined(PNG_READ_iCCP_SUPPORTED) || defined(PNG_READ_iTXt_SUPPORTED) ||\
+ defined(PNG_READ_pCAL_SUPPORTED) || defined(PNG_READ_sCAL_SUPPORTED) ||\
+ defined(PNG_READ_sPLT_SUPPORTED) || defined(PNG_READ_tEXt_SUPPORTED) ||\
+ defined(PNG_READ_zTXt_SUPPORTED) || defined(PNG_SEQUENTIAL_READ_SUPPORTED)
+/* Manage the read buffer; this simply reallocates the buffer if it is not small
+ * enough (or if it is not allocated). The routine returns a pointer to the
+ * buffer; if an error occurs and 'warn' is set the routine returns NULL, else
+ * it will call png_error (via png_malloc) on failure. (warn == 2 means
+ * 'silent').
+ */
+static png_bytep
+png_read_buffer(png_structrp png_ptr, png_alloc_size_t new_size, int warn)
+{
+ png_bytep buffer = png_ptr->read_buffer;
+
+ if (buffer != NULL && new_size > png_ptr->read_buffer_size)
+ {
+ png_ptr->read_buffer = NULL;
+ png_ptr->read_buffer = NULL;
+ png_ptr->read_buffer_size = 0;
+ png_free(png_ptr, buffer);
+ buffer = NULL;
+ }
+
+ if (buffer == NULL)
+ {
+ buffer = png_voidcast(png_bytep, png_malloc_base(png_ptr, new_size));
+
+ if (buffer != NULL)
+ {
+ png_ptr->read_buffer = buffer;
+ png_ptr->read_buffer_size = new_size;
+ }
+
+ else if (warn < 2) /* else silent */
+ {
+ if (warn != 0)
+ png_chunk_warning(png_ptr, "insufficient memory to read chunk");
+
+ else
+ png_chunk_error(png_ptr, "insufficient memory to read chunk");
+ }
+ }
+
+ return buffer;
+}
+#endif /* READ_iCCP|iTXt|pCAL|sCAL|sPLT|tEXt|zTXt|SEQUENTIAL_READ */
+
+/* png_inflate_claim: claim the zstream for some nefarious purpose that involves
+ * decompression. Returns Z_OK on success, else a zlib error code. It checks
+ * the owner but, in final release builds, just issues a warning if some other
+ * chunk apparently owns the stream. Prior to release it does a png_error.
+ */
+static int
+png_inflate_claim(png_structrp png_ptr, png_uint_32 owner)
+{
+ if (png_ptr->zowner != 0)
+ {
+ char msg[64];
+
+ PNG_STRING_FROM_CHUNK(msg, png_ptr->zowner);
+ /* So the message that results is "<chunk> using zstream"; this is an
+ * internal error, but is very useful for debugging. i18n requirements
+ * are minimal.
+ */
+ (void)png_safecat(msg, (sizeof msg), 4, " using zstream");
+#if PNG_LIBPNG_BUILD_BASE_TYPE >= PNG_LIBPNG_BUILD_RC
+ png_chunk_warning(png_ptr, msg);
+ png_ptr->zowner = 0;
+#else
+ png_chunk_error(png_ptr, msg);
+#endif
+ }
+
+ /* Implementation note: unlike 'png_deflate_claim' this internal function
+ * does not take the size of the data as an argument. Some efficiency could
+ * be gained by using this when it is known *if* the zlib stream itself does
+ * not record the number; however, this is an illusion: the original writer
+ * of the PNG may have selected a lower window size, and we really must
+ * follow that because, for systems with with limited capabilities, we
+ * would otherwise reject the application's attempts to use a smaller window
+ * size (zlib doesn't have an interface to say "this or lower"!).
+ *
+ * inflateReset2 was added to zlib 1.2.4; before this the window could not be
+ * reset, therefore it is necessary to always allocate the maximum window
+ * size with earlier zlibs just in case later compressed chunks need it.
+ */
+ {
+ int ret; /* zlib return code */
+#if PNG_ZLIB_VERNUM >= 0x1240
+
+# if defined(PNG_SET_OPTION_SUPPORTED) && defined(PNG_MAXIMUM_INFLATE_WINDOW)
+ int window_bits;
+
+ if (((png_ptr->options >> PNG_MAXIMUM_INFLATE_WINDOW) & 3) ==
+ PNG_OPTION_ON)
+ window_bits = 15;
+
+ else
+ window_bits = 0;
+# else
+# define window_bits 0
+# endif
+#endif
+
+ /* Set this for safety, just in case the previous owner left pointers to
+ * memory allocations.
+ */
+ png_ptr->zstream.next_in = NULL;
+ png_ptr->zstream.avail_in = 0;
+ png_ptr->zstream.next_out = NULL;
+ png_ptr->zstream.avail_out = 0;
+
+ if ((png_ptr->flags & PNG_FLAG_ZSTREAM_INITIALIZED) != 0)
+ {
+#if PNG_ZLIB_VERNUM < 0x1240
+ ret = inflateReset(&png_ptr->zstream);
+#else
+ ret = inflateReset2(&png_ptr->zstream, window_bits);
+#endif
+ }
+
+ else
+ {
+#if PNG_ZLIB_VERNUM < 0x1240
+ ret = inflateInit(&png_ptr->zstream);
+#else
+ ret = inflateInit2(&png_ptr->zstream, window_bits);
+#endif
+
+ if (ret == Z_OK)
+ png_ptr->flags |= PNG_FLAG_ZSTREAM_INITIALIZED;
+ }
+
+ if (ret == Z_OK)
+ png_ptr->zowner = owner;
+
+ else
+ png_zstream_error(png_ptr, ret);
+
+ return ret;
+ }
+
+#ifdef window_bits
+# undef window_bits
+#endif
+}
+
+#ifdef PNG_READ_COMPRESSED_TEXT_SUPPORTED
+/* png_inflate now returns zlib error codes including Z_OK and Z_STREAM_END to
+ * allow the caller to do multiple calls if required. If the 'finish' flag is
+ * set Z_FINISH will be passed to the final inflate() call and Z_STREAM_END must
+ * be returned or there has been a problem, otherwise Z_SYNC_FLUSH is used and
+ * Z_OK or Z_STREAM_END will be returned on success.
+ *
+ * The input and output sizes are updated to the actual amounts of data consumed
+ * or written, not the amount available (as in a z_stream). The data pointers
+ * are not changed, so the next input is (data+input_size) and the next
+ * available output is (output+output_size).
+ */
+static int
+png_inflate(png_structrp png_ptr, png_uint_32 owner, int finish,
+ /* INPUT: */ png_const_bytep input, png_uint_32p input_size_ptr,
+ /* OUTPUT: */ png_bytep output, png_alloc_size_t *output_size_ptr)
+{
+ if (png_ptr->zowner == owner) /* Else not claimed */
+ {
+ int ret;
+ png_alloc_size_t avail_out = *output_size_ptr;
+ png_uint_32 avail_in = *input_size_ptr;
+
+ /* zlib can't necessarily handle more than 65535 bytes at once (i.e. it
+ * can't even necessarily handle 65536 bytes) because the type uInt is
+ * "16 bits or more". Consequently it is necessary to chunk the input to
+ * zlib. This code uses ZLIB_IO_MAX, from pngpriv.h, as the maximum (the
+ * maximum value that can be stored in a uInt.) It is possible to set
+ * ZLIB_IO_MAX to a lower value in pngpriv.h and this may sometimes have
+ * a performance advantage, because it reduces the amount of data accessed
+ * at each step and that may give the OS more time to page it in.
+ */
+ png_ptr->zstream.next_in = PNGZ_INPUT_CAST(input);
+ /* avail_in and avail_out are set below from 'size' */
+ png_ptr->zstream.avail_in = 0;
+ png_ptr->zstream.avail_out = 0;
+
+ /* Read directly into the output if it is available (this is set to
+ * a local buffer below if output is NULL).
+ */
+ if (output != NULL)
+ png_ptr->zstream.next_out = output;
+
+ do
+ {
+ uInt avail;
+ Byte local_buffer[PNG_INFLATE_BUF_SIZE];
+
+ /* zlib INPUT BUFFER */
+ /* The setting of 'avail_in' used to be outside the loop; by setting it
+ * inside it is possible to chunk the input to zlib and simply rely on
+ * zlib to advance the 'next_in' pointer. This allows arbitrary
+ * amounts of data to be passed through zlib at the unavoidable cost of
+ * requiring a window save (memcpy of up to 32768 output bytes)
+ * every ZLIB_IO_MAX input bytes.
+ */
+ avail_in += png_ptr->zstream.avail_in; /* not consumed last time */
+
+ avail = ZLIB_IO_MAX;
+
+ if (avail_in < avail)
+ avail = (uInt)avail_in; /* safe: < than ZLIB_IO_MAX */
+
+ avail_in -= avail;
+ png_ptr->zstream.avail_in = avail;
+
+ /* zlib OUTPUT BUFFER */
+ avail_out += png_ptr->zstream.avail_out; /* not written last time */
+
+ avail = ZLIB_IO_MAX; /* maximum zlib can process */
+
+ if (output == NULL)
+ {
+ /* Reset the output buffer each time round if output is NULL and
+ * make available the full buffer, up to 'remaining_space'
+ */
+ png_ptr->zstream.next_out = local_buffer;
+ if ((sizeof local_buffer) < avail)
+ avail = (sizeof local_buffer);
+ }
+
+ if (avail_out < avail)
+ avail = (uInt)avail_out; /* safe: < ZLIB_IO_MAX */
+
+ png_ptr->zstream.avail_out = avail;
+ avail_out -= avail;
+
+ /* zlib inflate call */
+ /* In fact 'avail_out' may be 0 at this point, that happens at the end
+ * of the read when the final LZ end code was not passed at the end of
+ * the previous chunk of input data. Tell zlib if we have reached the
+ * end of the output buffer.
+ */
+ ret = inflate(&png_ptr->zstream, avail_out > 0 ? Z_NO_FLUSH :
+ (finish ? Z_FINISH : Z_SYNC_FLUSH));
+ } while (ret == Z_OK);
+
+ /* For safety kill the local buffer pointer now */
+ if (output == NULL)
+ png_ptr->zstream.next_out = NULL;
+
+ /* Claw back the 'size' and 'remaining_space' byte counts. */
+ avail_in += png_ptr->zstream.avail_in;
+ avail_out += png_ptr->zstream.avail_out;
+
+ /* Update the input and output sizes; the updated values are the amount
+ * consumed or written, effectively the inverse of what zlib uses.
+ */
+ if (avail_out > 0)
+ *output_size_ptr -= avail_out;
+
+ if (avail_in > 0)
+ *input_size_ptr -= avail_in;
+
+ /* Ensure png_ptr->zstream.msg is set (even in the success case!) */
+ png_zstream_error(png_ptr, ret);
+ return ret;
+ }
+
+ else
+ {
+ /* This is a bad internal error. The recovery assigns to the zstream msg
+ * pointer, which is not owned by the caller, but this is safe; it's only
+ * used on errors!
+ */
+ png_ptr->zstream.msg = PNGZ_MSG_CAST("zstream unclaimed");
+ return Z_STREAM_ERROR;
+ }
+}
+
+/*
+ * Decompress trailing data in a chunk. The assumption is that read_buffer
+ * points at an allocated area holding the contents of a chunk with a
+ * trailing compressed part. What we get back is an allocated area
+ * holding the original prefix part and an uncompressed version of the
+ * trailing part (the malloc area passed in is freed).
+ */
+static int
+png_decompress_chunk(png_structrp png_ptr,
+ png_uint_32 chunklength, png_uint_32 prefix_size,
+ png_alloc_size_t *newlength /* must be initialized to the maximum! */,
+ int terminate /*add a '\0' to the end of the uncompressed data*/)
+{
+ /* TODO: implement different limits for different types of chunk.
+ *
+ * The caller supplies *newlength set to the maximum length of the
+ * uncompressed data, but this routine allocates space for the prefix and
+ * maybe a '\0' terminator too. We have to assume that 'prefix_size' is
+ * limited only by the maximum chunk size.
+ */
+ png_alloc_size_t limit = PNG_SIZE_MAX;
+
+# ifdef PNG_SET_CHUNK_MALLOC_LIMIT_SUPPORTED
+ if (png_ptr->user_chunk_malloc_max > 0 &&
+ png_ptr->user_chunk_malloc_max < limit)
+ limit = png_ptr->user_chunk_malloc_max;
+# elif PNG_USER_CHUNK_MALLOC_MAX > 0
+ if (PNG_USER_CHUNK_MALLOC_MAX < limit)
+ limit = PNG_USER_CHUNK_MALLOC_MAX;
+# endif
+
+ if (limit >= prefix_size + (terminate != 0))
+ {
+ int ret;
+
+ limit -= prefix_size + (terminate != 0);
+
+ if (limit < *newlength)
+ *newlength = limit;
+
+ /* Now try to claim the stream. */
+ ret = png_inflate_claim(png_ptr, png_ptr->chunk_name);
+
+ if (ret == Z_OK)
+ {
+ png_uint_32 lzsize = chunklength - prefix_size;
+
+ ret = png_inflate(png_ptr, png_ptr->chunk_name, 1/*finish*/,
+ /* input: */ png_ptr->read_buffer + prefix_size, &lzsize,
+ /* output: */ NULL, newlength);
+
+ if (ret == Z_STREAM_END)
+ {
+ /* Use 'inflateReset' here, not 'inflateReset2' because this
+ * preserves the previously decided window size (otherwise it would
+ * be necessary to store the previous window size.) In practice
+ * this doesn't matter anyway, because png_inflate will call inflate
+ * with Z_FINISH in almost all cases, so the window will not be
+ * maintained.
+ */
+ if (inflateReset(&png_ptr->zstream) == Z_OK)
+ {
+ /* Because of the limit checks above we know that the new,
+ * expanded, size will fit in a size_t (let alone an
+ * png_alloc_size_t). Use png_malloc_base here to avoid an
+ * extra OOM message.
+ */
+ png_alloc_size_t new_size = *newlength;
+ png_alloc_size_t buffer_size = prefix_size + new_size +
+ (terminate != 0);
+ png_bytep text = png_voidcast(png_bytep, png_malloc_base(png_ptr,
+ buffer_size));
+
+ if (text != NULL)
+ {
+ ret = png_inflate(png_ptr, png_ptr->chunk_name, 1/*finish*/,
+ png_ptr->read_buffer + prefix_size, &lzsize,
+ text + prefix_size, newlength);
+
+ if (ret == Z_STREAM_END)
+ {
+ if (new_size == *newlength)
+ {
+ if (terminate != 0)
+ text[prefix_size + *newlength] = 0;
+
+ if (prefix_size > 0)
+ memcpy(text, png_ptr->read_buffer, prefix_size);
+
+ {
+ png_bytep old_ptr = png_ptr->read_buffer;
+
+ png_ptr->read_buffer = text;
+ png_ptr->read_buffer_size = buffer_size;
+ text = old_ptr; /* freed below */
+ }
+ }
+
+ else
+ {
+ /* The size changed on the second read, there can be no
+ * guarantee that anything is correct at this point.
+ * The 'msg' pointer has been set to "unexpected end of
+ * LZ stream", which is fine, but return an error code
+ * that the caller won't accept.
+ */
+ ret = PNG_UNEXPECTED_ZLIB_RETURN;
+ }
+ }
+
+ else if (ret == Z_OK)
+ ret = PNG_UNEXPECTED_ZLIB_RETURN; /* for safety */
+
+ /* Free the text pointer (this is the old read_buffer on
+ * success)
+ */
+ png_free(png_ptr, text);
+ text = NULL;
+
+ /* This really is very benign, but it's still an error because
+ * the extra space may otherwise be used as a Trojan Horse.
+ */
+ if (ret == Z_STREAM_END &&
+ chunklength - prefix_size != lzsize)
+ png_chunk_benign_error(png_ptr, "extra compressed data");
+ }
+
+ else
+ {
+ /* Out of memory allocating the buffer */
+ ret = Z_MEM_ERROR;
+ png_zstream_error(png_ptr, Z_MEM_ERROR);
+ }
+ }
+
+ else
+ {
+ /* inflateReset failed, store the error message */
+ png_zstream_error(png_ptr, ret);
+
+ if (ret == Z_STREAM_END)
+ ret = PNG_UNEXPECTED_ZLIB_RETURN;
+ }
+ }
+
+ else if (ret == Z_OK)
+ ret = PNG_UNEXPECTED_ZLIB_RETURN;
+
+ /* Release the claimed stream */
+ png_ptr->zowner = 0;
+ }
+
+ else /* the claim failed */ if (ret == Z_STREAM_END) /* impossible! */
+ ret = PNG_UNEXPECTED_ZLIB_RETURN;
+
+ return ret;
+ }
+
+ else
+ {
+ /* Application/configuration limits exceeded */
+ png_zstream_error(png_ptr, Z_MEM_ERROR);
+ return Z_MEM_ERROR;
+ }
+}
+#endif /* READ_COMPRESSED_TEXT */
+
+#ifdef PNG_READ_iCCP_SUPPORTED
+/* Perform a partial read and decompress, producing 'avail_out' bytes and
+ * reading from the current chunk as required.
+ */
+static int
+png_inflate_read(png_structrp png_ptr, png_bytep read_buffer, uInt read_size,
+ png_uint_32p chunk_bytes, png_bytep next_out, png_alloc_size_t *out_size,
+ int finish)
+{
+ if (png_ptr->zowner == png_ptr->chunk_name)
+ {
+ int ret;
+
+ /* next_in and avail_in must have been initialized by the caller. */
+ png_ptr->zstream.next_out = next_out;
+ png_ptr->zstream.avail_out = 0; /* set in the loop */
+
+ do
+ {
+ if (png_ptr->zstream.avail_in == 0)
+ {
+ if (read_size > *chunk_bytes)
+ read_size = (uInt)*chunk_bytes;
+ *chunk_bytes -= read_size;
+
+ if (read_size > 0)
+ png_crc_read(png_ptr, read_buffer, read_size);
+
+ png_ptr->zstream.next_in = read_buffer;
+ png_ptr->zstream.avail_in = read_size;
+ }
+
+ if (png_ptr->zstream.avail_out == 0)
+ {
+ uInt avail = ZLIB_IO_MAX;
+ if (avail > *out_size)
+ avail = (uInt)*out_size;
+ *out_size -= avail;
+
+ png_ptr->zstream.avail_out = avail;
+ }
+
+ /* Use Z_SYNC_FLUSH when there is no more chunk data to ensure that all
+ * the available output is produced; this allows reading of truncated
+ * streams.
+ */
+ ret = inflate(&png_ptr->zstream,
+ *chunk_bytes > 0 ? Z_NO_FLUSH : (finish ? Z_FINISH : Z_SYNC_FLUSH));
+ }
+ while (ret == Z_OK && (*out_size > 0 || png_ptr->zstream.avail_out > 0));
+
+ *out_size += png_ptr->zstream.avail_out;
+ png_ptr->zstream.avail_out = 0; /* Should not be required, but is safe */
+
+ /* Ensure the error message pointer is always set: */
+ png_zstream_error(png_ptr, ret);
+ return ret;
+ }
+
+ else
+ {
+ png_ptr->zstream.msg = PNGZ_MSG_CAST("zstream unclaimed");
+ return Z_STREAM_ERROR;
+ }
+}
+#endif
+
+/* Read and check the IDHR chunk */
+
+void /* PRIVATE */
+png_handle_IHDR(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
+{
+ png_byte buf[13];
+ png_uint_32 width, height;
+ int bit_depth, color_type, compression_type, filter_type;
+ int interlace_type;
+
+ png_debug(1, "in png_handle_IHDR");
+
+ if ((png_ptr->mode & PNG_HAVE_IHDR) != 0)
+ png_chunk_error(png_ptr, "out of place");
+
+ /* Check the length */
+ if (length != 13)
+ png_chunk_error(png_ptr, "invalid");
+
+ png_ptr->mode |= PNG_HAVE_IHDR;
+
+ png_crc_read(png_ptr, buf, 13);
+ png_crc_finish(png_ptr, 0);
+
+ width = png_get_uint_31(png_ptr, buf);
+ height = png_get_uint_31(png_ptr, buf + 4);
+ bit_depth = buf[8];
+ color_type = buf[9];
+ compression_type = buf[10];
+ filter_type = buf[11];
+ interlace_type = buf[12];
+
+ /* Set internal variables */
+ png_ptr->width = width;
+ png_ptr->height = height;
+ png_ptr->bit_depth = (png_byte)bit_depth;
+ png_ptr->interlaced = (png_byte)interlace_type;
+ png_ptr->color_type = (png_byte)color_type;
+#ifdef PNG_MNG_FEATURES_SUPPORTED
+ png_ptr->filter_type = (png_byte)filter_type;
+#endif
+ png_ptr->compression_type = (png_byte)compression_type;
+
+ /* Find number of channels */
+ switch (png_ptr->color_type)
+ {
+ default: /* invalid, png_set_IHDR calls png_error */
+ case PNG_COLOR_TYPE_GRAY:
+ case PNG_COLOR_TYPE_PALETTE:
+ png_ptr->channels = 1;
+ break;
+
+ case PNG_COLOR_TYPE_RGB:
+ png_ptr->channels = 3;
+ break;
+
+ case PNG_COLOR_TYPE_GRAY_ALPHA:
+ png_ptr->channels = 2;
+ break;
+
+ case PNG_COLOR_TYPE_RGB_ALPHA:
+ png_ptr->channels = 4;
+ break;
+ }
+
+ /* Set up other useful info */
+ png_ptr->pixel_depth = (png_byte)(png_ptr->bit_depth * png_ptr->channels);
+ png_ptr->rowbytes = PNG_ROWBYTES(png_ptr->pixel_depth, png_ptr->width);
+ png_debug1(3, "bit_depth = %d", png_ptr->bit_depth);
+ png_debug1(3, "channels = %d", png_ptr->channels);
+ png_debug1(3, "rowbytes = %lu", (unsigned long)png_ptr->rowbytes);
+ png_set_IHDR(png_ptr, info_ptr, width, height, bit_depth,
+ color_type, interlace_type, compression_type, filter_type);
+}
+
+/* Read and check the palette */
+void /* PRIVATE */
+png_handle_PLTE(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
+{
+ png_color palette[PNG_MAX_PALETTE_LENGTH];
+ int num, i;
+#ifdef PNG_POINTER_INDEXING_SUPPORTED
+ png_colorp pal_ptr;
+#endif
+
+ png_debug(1, "in png_handle_PLTE");
+
+ if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
+ png_chunk_error(png_ptr, "missing IHDR");
+
+ /* Moved to before the 'after IDAT' check below because otherwise duplicate
+ * PLTE chunks are potentially ignored (the spec says there shall not be more
+ * than one PLTE, the error is not treated as benign, so this check trumps
+ * the requirement that PLTE appears before IDAT.)
+ */
+ else if ((png_ptr->mode & PNG_HAVE_PLTE) != 0)
+ png_chunk_error(png_ptr, "duplicate");
+
+ else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
+ {
+ /* This is benign because the non-benign error happened before, when an
+ * IDAT was encountered in a color-mapped image with no PLTE.
+ */
+ png_crc_finish(png_ptr, length);
+ png_chunk_benign_error(png_ptr, "out of place");
+ return;
+ }
+
+ png_ptr->mode |= PNG_HAVE_PLTE;
+
+ if ((png_ptr->color_type & PNG_COLOR_MASK_COLOR) == 0)
+ {
+ png_crc_finish(png_ptr, length);
+ png_chunk_benign_error(png_ptr, "ignored in grayscale PNG");
+ return;
+ }
+
+#ifndef PNG_READ_OPT_PLTE_SUPPORTED
+ if (png_ptr->color_type != PNG_COLOR_TYPE_PALETTE)
+ {
+ png_crc_finish(png_ptr, length);
+ return;
+ }
+#endif
+
+ if (length > 3*PNG_MAX_PALETTE_LENGTH || length % 3)
+ {
+ png_crc_finish(png_ptr, length);
+
+ if (png_ptr->color_type != PNG_COLOR_TYPE_PALETTE)
+ png_chunk_benign_error(png_ptr, "invalid");
+
+ else
+ png_chunk_error(png_ptr, "invalid");
+
+ return;
+ }
+
+ /* The cast is safe because 'length' is less than 3*PNG_MAX_PALETTE_LENGTH */
+ num = (int)length / 3;
+
+#ifdef PNG_POINTER_INDEXING_SUPPORTED
+ for (i = 0, pal_ptr = palette; i < num; i++, pal_ptr++)
+ {
+ png_byte buf[3];
+
+ png_crc_read(png_ptr, buf, 3);
+ pal_ptr->red = buf[0];
+ pal_ptr->green = buf[1];
+ pal_ptr->blue = buf[2];
+ }
+#else
+ for (i = 0; i < num; i++)
+ {
+ png_byte buf[3];
+
+ png_crc_read(png_ptr, buf, 3);
+ /* Don't depend upon png_color being any order */
+ palette[i].red = buf[0];
+ palette[i].green = buf[1];
+ palette[i].blue = buf[2];
+ }
+#endif
+
+ /* If we actually need the PLTE chunk (ie for a paletted image), we do
+ * whatever the normal CRC configuration tells us. However, if we
+ * have an RGB image, the PLTE can be considered ancillary, so
+ * we will act as though it is.
+ */
+#ifndef PNG_READ_OPT_PLTE_SUPPORTED
+ if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
+#endif
+ {
+ png_crc_finish(png_ptr, 0);
+ }
+
+#ifndef PNG_READ_OPT_PLTE_SUPPORTED
+ else if (png_crc_error(png_ptr) != 0) /* Only if we have a CRC error */
+ {
+ /* If we don't want to use the data from an ancillary chunk,
+ * we have two options: an error abort, or a warning and we
+ * ignore the data in this chunk (which should be OK, since
+ * it's considered ancillary for a RGB or RGBA image).
+ *
+ * IMPLEMENTATION NOTE: this is only here because png_crc_finish uses the
+ * chunk type to determine whether to check the ancillary or the critical
+ * flags.
+ */
+ if ((png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_USE) == 0)
+ {
+ if ((png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_NOWARN) != 0)
+ return;
+
+ else
+ png_chunk_error(png_ptr, "CRC error");
+ }
+
+ /* Otherwise, we (optionally) emit a warning and use the chunk. */
+ else if ((png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_NOWARN) == 0)
+ png_chunk_warning(png_ptr, "CRC error");
+ }
+#endif
+
+ /* TODO: png_set_PLTE has the side effect of setting png_ptr->palette to its
+ * own copy of the palette. This has the side effect that when png_start_row
+ * is called (this happens after any call to png_read_update_info) the
+ * info_ptr palette gets changed. This is extremely unexpected and
+ * confusing.
+ *
+ * Fix this by not sharing the palette in this way.
+ */
+ png_set_PLTE(png_ptr, info_ptr, palette, num);
+
+ /* The three chunks, bKGD, hIST and tRNS *must* appear after PLTE and before
+ * IDAT. Prior to 1.6.0 this was not checked; instead the code merely
+ * checked the apparent validity of a tRNS chunk inserted before PLTE on a
+ * palette PNG. 1.6.0 attempts to rigorously follow the standard and
+ * therefore does a benign error if the erroneous condition is detected *and*
+ * cancels the tRNS if the benign error returns. The alternative is to
+ * amend the standard since it would be rather hypocritical of the standards
+ * maintainers to ignore it.
+ */
+#ifdef PNG_READ_tRNS_SUPPORTED
+ if (png_ptr->num_trans > 0 ||
+ (info_ptr != NULL && (info_ptr->valid & PNG_INFO_tRNS) != 0))
+ {
+ /* Cancel this because otherwise it would be used if the transforms
+ * require it. Don't cancel the 'valid' flag because this would prevent
+ * detection of duplicate chunks.
+ */
+ png_ptr->num_trans = 0;
+
+ if (info_ptr != NULL)
+ info_ptr->num_trans = 0;
+
+ png_chunk_benign_error(png_ptr, "tRNS must be after");
+ }
+#endif
+
+#ifdef PNG_READ_hIST_SUPPORTED
+ if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_hIST) != 0)
+ png_chunk_benign_error(png_ptr, "hIST must be after");
+#endif
+
+#ifdef PNG_READ_bKGD_SUPPORTED
+ if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_bKGD) != 0)
+ png_chunk_benign_error(png_ptr, "bKGD must be after");
+#endif
+}
+
+void /* PRIVATE */
+png_handle_IEND(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
+{
+ png_debug(1, "in png_handle_IEND");
+
+ if ((png_ptr->mode & PNG_HAVE_IHDR) == 0 ||
+ (png_ptr->mode & PNG_HAVE_IDAT) == 0)
+ png_chunk_error(png_ptr, "out of place");
+
+ png_ptr->mode |= (PNG_AFTER_IDAT | PNG_HAVE_IEND);
+
+ png_crc_finish(png_ptr, length);
+
+ if (length != 0)
+ png_chunk_benign_error(png_ptr, "invalid");
+
+ PNG_UNUSED(info_ptr)
+}
+
+#ifdef PNG_READ_gAMA_SUPPORTED
+void /* PRIVATE */
+png_handle_gAMA(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
+{
+ png_fixed_point igamma;
+ png_byte buf[4];
+
+ png_debug(1, "in png_handle_gAMA");
+
+ if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
+ png_chunk_error(png_ptr, "missing IHDR");
+
+ else if ((png_ptr->mode & (PNG_HAVE_IDAT|PNG_HAVE_PLTE)) != 0)
+ {
+ png_crc_finish(png_ptr, length);
+ png_chunk_benign_error(png_ptr, "out of place");
+ return;
+ }
+
+ if (length != 4)
+ {
+ png_crc_finish(png_ptr, length);
+ png_chunk_benign_error(png_ptr, "invalid");
+ return;
+ }
+
+ png_crc_read(png_ptr, buf, 4);
+
+ if (png_crc_finish(png_ptr, 0) != 0)
+ return;
+
+ igamma = png_get_fixed_point(NULL, buf);
+
+ png_colorspace_set_gamma(png_ptr, &png_ptr->colorspace, igamma);
+ png_colorspace_sync(png_ptr, info_ptr);
+}
+#endif
+
+#ifdef PNG_READ_sBIT_SUPPORTED
+void /* PRIVATE */
+png_handle_sBIT(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
+{
+ unsigned int truelen, i;
+ png_byte sample_depth;
+ png_byte buf[4];
+
+ png_debug(1, "in png_handle_sBIT");
+
+ if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
+ png_chunk_error(png_ptr, "missing IHDR");
+
+ else if ((png_ptr->mode & (PNG_HAVE_IDAT|PNG_HAVE_PLTE)) != 0)
+ {
+ png_crc_finish(png_ptr, length);
+ png_chunk_benign_error(png_ptr, "out of place");
+ return;
+ }
+
+ if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_sBIT) != 0)
+ {
+ png_crc_finish(png_ptr, length);
+ png_chunk_benign_error(png_ptr, "duplicate");
+ return;
+ }
+
+ if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
+ {
+ truelen = 3;
+ sample_depth = 8;
+ }
+
+ else
+ {
+ truelen = png_ptr->channels;
+ sample_depth = png_ptr->bit_depth;
+ }
+
+ if (length != truelen || length > 4)
+ {
+ png_chunk_benign_error(png_ptr, "invalid");
+ png_crc_finish(png_ptr, length);
+ return;
+ }
+
+ buf[0] = buf[1] = buf[2] = buf[3] = sample_depth;
+ png_crc_read(png_ptr, buf, truelen);
+
+ if (png_crc_finish(png_ptr, 0) != 0)
+ return;
+
+ for (i=0; i<truelen; ++i)
+ if (buf[i] == 0 || buf[i] > sample_depth)
+ {
+ png_chunk_benign_error(png_ptr, "invalid");
+ return;
+ }
+
+ if ((png_ptr->color_type & PNG_COLOR_MASK_COLOR) != 0)
+ {
+ png_ptr->sig_bit.red = buf[0];
+ png_ptr->sig_bit.green = buf[1];
+ png_ptr->sig_bit.blue = buf[2];
+ png_ptr->sig_bit.alpha = buf[3];
+ }
+
+ else
+ {
+ png_ptr->sig_bit.gray = buf[0];
+ png_ptr->sig_bit.red = buf[0];
+ png_ptr->sig_bit.green = buf[0];
+ png_ptr->sig_bit.blue = buf[0];
+ png_ptr->sig_bit.alpha = buf[1];
+ }
+
+ png_set_sBIT(png_ptr, info_ptr, &(png_ptr->sig_bit));
+}
+#endif
+
+#ifdef PNG_READ_cHRM_SUPPORTED
+void /* PRIVATE */
+png_handle_cHRM(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
+{
+ png_byte buf[32];
+ png_xy xy;
+
+ png_debug(1, "in png_handle_cHRM");
+
+ if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
+ png_chunk_error(png_ptr, "missing IHDR");
+
+ else if ((png_ptr->mode & (PNG_HAVE_IDAT|PNG_HAVE_PLTE)) != 0)
+ {
+ png_crc_finish(png_ptr, length);
+ png_chunk_benign_error(png_ptr, "out of place");
+ return;
+ }
+
+ if (length != 32)
+ {
+ png_crc_finish(png_ptr, length);
+ png_chunk_benign_error(png_ptr, "invalid");
+ return;
+ }
+
+ png_crc_read(png_ptr, buf, 32);
+
+ if (png_crc_finish(png_ptr, 0) != 0)
+ return;
+
+ xy.whitex = png_get_fixed_point(NULL, buf);
+ xy.whitey = png_get_fixed_point(NULL, buf + 4);
+ xy.redx = png_get_fixed_point(NULL, buf + 8);
+ xy.redy = png_get_fixed_point(NULL, buf + 12);
+ xy.greenx = png_get_fixed_point(NULL, buf + 16);
+ xy.greeny = png_get_fixed_point(NULL, buf + 20);
+ xy.bluex = png_get_fixed_point(NULL, buf + 24);
+ xy.bluey = png_get_fixed_point(NULL, buf + 28);
+
+ if (xy.whitex == PNG_FIXED_ERROR ||
+ xy.whitey == PNG_FIXED_ERROR ||
+ xy.redx == PNG_FIXED_ERROR ||
+ xy.redy == PNG_FIXED_ERROR ||
+ xy.greenx == PNG_FIXED_ERROR ||
+ xy.greeny == PNG_FIXED_ERROR ||
+ xy.bluex == PNG_FIXED_ERROR ||
+ xy.bluey == PNG_FIXED_ERROR)
+ {
+ png_chunk_benign_error(png_ptr, "invalid values");
+ return;
+ }
+
+ /* If a colorspace error has already been output skip this chunk */
+ if ((png_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) != 0)
+ return;
+
+ if ((png_ptr->colorspace.flags & PNG_COLORSPACE_FROM_cHRM) != 0)
+ {
+ png_ptr->colorspace.flags |= PNG_COLORSPACE_INVALID;
+ png_colorspace_sync(png_ptr, info_ptr);
+ png_chunk_benign_error(png_ptr, "duplicate");
+ return;
+ }
+
+ png_ptr->colorspace.flags |= PNG_COLORSPACE_FROM_cHRM;
+ (void)png_colorspace_set_chromaticities(png_ptr, &png_ptr->colorspace, &xy,
+ 1/*prefer cHRM values*/);
+ png_colorspace_sync(png_ptr, info_ptr);
+}
+#endif
+
+#ifdef PNG_READ_sRGB_SUPPORTED
+void /* PRIVATE */
+png_handle_sRGB(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
+{
+ png_byte intent;
+
+ png_debug(1, "in png_handle_sRGB");
+
+ if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
+ png_chunk_error(png_ptr, "missing IHDR");
+
+ else if ((png_ptr->mode & (PNG_HAVE_IDAT|PNG_HAVE_PLTE)) != 0)
+ {
+ png_crc_finish(png_ptr, length);
+ png_chunk_benign_error(png_ptr, "out of place");
+ return;
+ }
+
+ if (length != 1)
+ {
+ png_crc_finish(png_ptr, length);
+ png_chunk_benign_error(png_ptr, "invalid");
+ return;
+ }
+
+ png_crc_read(png_ptr, &intent, 1);
+
+ if (png_crc_finish(png_ptr, 0) != 0)
+ return;
+
+ /* If a colorspace error has already been output skip this chunk */
+ if ((png_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) != 0)
+ return;
+
+ /* Only one sRGB or iCCP chunk is allowed, use the HAVE_INTENT flag to detect
+ * this.
+ */
+ if ((png_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_INTENT) != 0)
+ {
+ png_ptr->colorspace.flags |= PNG_COLORSPACE_INVALID;
+ png_colorspace_sync(png_ptr, info_ptr);
+ png_chunk_benign_error(png_ptr, "too many profiles");
+ return;
+ }
+
+ (void)png_colorspace_set_sRGB(png_ptr, &png_ptr->colorspace, intent);
+ png_colorspace_sync(png_ptr, info_ptr);
+}
+#endif /* READ_sRGB */
+
+#ifdef PNG_READ_iCCP_SUPPORTED
+void /* PRIVATE */
+png_handle_iCCP(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
+/* Note: this does not properly handle profiles that are > 64K under DOS */
+{
+ png_const_charp errmsg = NULL; /* error message output, or no error */
+ int finished = 0; /* crc checked */
+
+ png_debug(1, "in png_handle_iCCP");
+
+ if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
+ png_chunk_error(png_ptr, "missing IHDR");
+
+ else if ((png_ptr->mode & (PNG_HAVE_IDAT|PNG_HAVE_PLTE)) != 0)
+ {
+ png_crc_finish(png_ptr, length);
+ png_chunk_benign_error(png_ptr, "out of place");
+ return;
+ }
+
+ /* Consistent with all the above colorspace handling an obviously *invalid*
+ * chunk is just ignored, so does not invalidate the color space. An
+ * alternative is to set the 'invalid' flags at the start of this routine
+ * and only clear them in they were not set before and all the tests pass.
+ * The minimum 'deflate' stream is assumed to be just the 2 byte header and
+ * 4 byte checksum. The keyword must be at least one character and there is
+ * a terminator (0) byte and the compression method.
+ */
+ if (length < 9)
+ {
+ png_crc_finish(png_ptr, length);
+ png_chunk_benign_error(png_ptr, "too short");
+ return;
+ }
+
+ /* If a colorspace error has already been output skip this chunk */
+ if ((png_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) != 0)
+ {
+ png_crc_finish(png_ptr, length);
+ return;
+ }
+
+ /* Only one sRGB or iCCP chunk is allowed, use the HAVE_INTENT flag to detect
+ * this.
+ */
+ if ((png_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_INTENT) == 0)
+ {
+ uInt read_length, keyword_length;
+ char keyword[81];
+
+ /* Find the keyword; the keyword plus separator and compression method
+ * bytes can be at most 81 characters long.
+ */
+ read_length = 81; /* maximum */
+ if (read_length > length)
+ read_length = (uInt)length;
+
+ png_crc_read(png_ptr, (png_bytep)keyword, read_length);
+ length -= read_length;
+
+ keyword_length = 0;
+ while (keyword_length < 80 && keyword_length < read_length &&
+ keyword[keyword_length] != 0)
+ ++keyword_length;
+
+ /* TODO: make the keyword checking common */
+ if (keyword_length >= 1 && keyword_length <= 79)
+ {
+ /* We only understand '0' compression - deflate - so if we get a
+ * different value we can't safely decode the chunk.
+ */
+ if (keyword_length+1 < read_length &&
+ keyword[keyword_length+1] == PNG_COMPRESSION_TYPE_BASE)
+ {
+ read_length -= keyword_length+2;
+
+ if (png_inflate_claim(png_ptr, png_iCCP) == Z_OK)
+ {
+ Byte profile_header[132];
+ Byte local_buffer[PNG_INFLATE_BUF_SIZE];
+ png_alloc_size_t size = (sizeof profile_header);
+
+ png_ptr->zstream.next_in = (Bytef*)keyword + (keyword_length+2);
+ png_ptr->zstream.avail_in = read_length;
+ (void)png_inflate_read(png_ptr, local_buffer,
+ (sizeof local_buffer), &length, profile_header, &size,
+ 0/*finish: don't, because the output is too small*/);
+
+ if (size == 0)
+ {
+ /* We have the ICC profile header; do the basic header checks.
+ */
+ const png_uint_32 profile_length =
+ png_get_uint_32(profile_header);
+
+ if (png_icc_check_length(png_ptr, &png_ptr->colorspace,
+ keyword, profile_length) != 0)
+ {
+ /* The length is apparently ok, so we can check the 132
+ * byte header.
+ */
+ if (png_icc_check_header(png_ptr, &png_ptr->colorspace,
+ keyword, profile_length, profile_header,
+ png_ptr->color_type) != 0)
+ {
+ /* Now read the tag table; a variable size buffer is
+ * needed at this point, allocate one for the whole
+ * profile. The header check has already validated
+ * that none of these stuff will overflow.
+ */
+ const png_uint_32 tag_count = png_get_uint_32(
+ profile_header+128);
+ png_bytep profile = png_read_buffer(png_ptr,
+ profile_length, 2/*silent*/);
+
+ if (profile != NULL)
+ {
+ memcpy(profile, profile_header,
+ (sizeof profile_header));
+
+ size = 12 * tag_count;
+
+ (void)png_inflate_read(png_ptr, local_buffer,
+ (sizeof local_buffer), &length,
+ profile + (sizeof profile_header), &size, 0);
+
+ /* Still expect a buffer error because we expect
+ * there to be some tag data!
+ */
+ if (size == 0)
+ {
+ if (png_icc_check_tag_table(png_ptr,
+ &png_ptr->colorspace, keyword, profile_length,
+ profile) != 0)
+ {
+ /* The profile has been validated for basic
+ * security issues, so read the whole thing in.
+ */
+ size = profile_length - (sizeof profile_header)
+ - 12 * tag_count;
+
+ (void)png_inflate_read(png_ptr, local_buffer,
+ (sizeof local_buffer), &length,
+ profile + (sizeof profile_header) +
+ 12 * tag_count, &size, 1/*finish*/);
+
+ if (length > 0 && !(png_ptr->flags &
+ PNG_FLAG_BENIGN_ERRORS_WARN))
+ errmsg = "extra compressed data";
+
+ /* But otherwise allow extra data: */
+ else if (size == 0)
+ {
+ if (length > 0)
+ {
+ /* This can be handled completely, so
+ * keep going.
+ */
+ png_chunk_warning(png_ptr,
+ "extra compressed data");
+ }
+
+ png_crc_finish(png_ptr, length);
+ finished = 1;
+
+# ifdef PNG_sRGB_SUPPORTED
+ /* Check for a match against sRGB */
+ png_icc_set_sRGB(png_ptr,
+ &png_ptr->colorspace, profile,
+ png_ptr->zstream.adler);
+# endif
+
+ /* Steal the profile for info_ptr. */
+ if (info_ptr != NULL)
+ {
+ png_free_data(png_ptr, info_ptr,
+ PNG_FREE_ICCP, 0);
+
+ info_ptr->iccp_name = png_voidcast(char*,
+ png_malloc_base(png_ptr,
+ keyword_length+1));
+ if (info_ptr->iccp_name != NULL)
+ {
+ memcpy(info_ptr->iccp_name, keyword,
+ keyword_length+1);
+ info_ptr->iccp_proflen =
+ profile_length;
+ info_ptr->iccp_profile = profile;
+ png_ptr->read_buffer = NULL; /*steal*/
+ info_ptr->free_me |= PNG_FREE_ICCP;
+ info_ptr->valid |= PNG_INFO_iCCP;
+ }
+
+ else
+ {
+ png_ptr->colorspace.flags |=
+ PNG_COLORSPACE_INVALID;
+ errmsg = "out of memory";
+ }
+ }
+
+ /* else the profile remains in the read
+ * buffer which gets reused for subsequent
+ * chunks.
+ */
+
+ if (info_ptr != NULL)
+ png_colorspace_sync(png_ptr, info_ptr);
+
+ if (errmsg == NULL)
+ {
+ png_ptr->zowner = 0;
+ return;
+ }
+ }
+
+ else if (size > 0)
+ errmsg = "truncated";
+
+#ifndef __COVERITY__
+ else
+ errmsg = png_ptr->zstream.msg;
+#endif
+ }
+
+ /* else png_icc_check_tag_table output an error */
+ }
+
+ else /* profile truncated */
+ errmsg = png_ptr->zstream.msg;
+ }
+
+ else
+ errmsg = "out of memory";
+ }
+
+ /* else png_icc_check_header output an error */
+ }
+
+ /* else png_icc_check_length output an error */
+ }
+
+ else /* profile truncated */
+ errmsg = png_ptr->zstream.msg;
+
+ /* Release the stream */
+ png_ptr->zowner = 0;
+ }
+
+ else /* png_inflate_claim failed */
+ errmsg = png_ptr->zstream.msg;
+ }
+
+ else
+ errmsg = "bad compression method"; /* or missing */
+ }
+
+ else
+ errmsg = "bad keyword";
+ }
+
+ else
+ errmsg = "too many profiles";
+
+ /* Failure: the reason is in 'errmsg' */
+ if (finished == 0)
+ png_crc_finish(png_ptr, length);
+
+ png_ptr->colorspace.flags |= PNG_COLORSPACE_INVALID;
+ png_colorspace_sync(png_ptr, info_ptr);
+ if (errmsg != NULL) /* else already output */
+ png_chunk_benign_error(png_ptr, errmsg);
+}
+#endif /* READ_iCCP */
+
+#ifdef PNG_READ_sPLT_SUPPORTED
+void /* PRIVATE */
+png_handle_sPLT(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
+/* Note: this does not properly handle chunks that are > 64K under DOS */
+{
+ png_bytep entry_start, buffer;
+ png_sPLT_t new_palette;
+ png_sPLT_entryp pp;
+ png_uint_32 data_length;
+ int entry_size, i;
+ png_uint_32 skip = 0;
+ png_uint_32 dl;
+ png_size_t max_dl;
+
+ png_debug(1, "in png_handle_sPLT");
+
+#ifdef PNG_USER_LIMITS_SUPPORTED
+ if (png_ptr->user_chunk_cache_max != 0)
+ {
+ if (png_ptr->user_chunk_cache_max == 1)
+ {
+ png_crc_finish(png_ptr, length);
+ return;
+ }
+
+ if (--png_ptr->user_chunk_cache_max == 1)
+ {
+ png_warning(png_ptr, "No space in chunk cache for sPLT");
+ png_crc_finish(png_ptr, length);
+ return;
+ }
+ }
+#endif
+
+ if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
+ png_chunk_error(png_ptr, "missing IHDR");
+
+ else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
+ {
+ png_crc_finish(png_ptr, length);
+ png_chunk_benign_error(png_ptr, "out of place");
+ return;
+ }
+
+#ifdef PNG_MAX_MALLOC_64K
+ if (length > 65535U)
+ {
+ png_crc_finish(png_ptr, length);
+ png_chunk_benign_error(png_ptr, "too large to fit in memory");
+ return;
+ }
+#endif
+
+ buffer = png_read_buffer(png_ptr, length+1, 2/*silent*/);
+ if (buffer == NULL)
+ {
+ png_crc_finish(png_ptr, length);
+ png_chunk_benign_error(png_ptr, "out of memory");
+ return;
+ }
+
+
+ /* WARNING: this may break if size_t is less than 32 bits; it is assumed
+ * that the PNG_MAX_MALLOC_64K test is enabled in this case, but this is a
+ * potential breakage point if the types in pngconf.h aren't exactly right.
+ */
+ png_crc_read(png_ptr, buffer, length);
+
+ if (png_crc_finish(png_ptr, skip) != 0)
+ return;
+
+ buffer[length] = 0;
+
+ for (entry_start = buffer; *entry_start; entry_start++)
+ /* Empty loop to find end of name */ ;
+
+ ++entry_start;
+
+ /* A sample depth should follow the separator, and we should be on it */
+ if (entry_start > buffer + length - 2)
+ {
+ png_warning(png_ptr, "malformed sPLT chunk");
+ return;
+ }
+
+ new_palette.depth = *entry_start++;
+ entry_size = (new_palette.depth == 8 ? 6 : 10);
+ /* This must fit in a png_uint_32 because it is derived from the original
+ * chunk data length.
+ */
+ data_length = length - (png_uint_32)(entry_start - buffer);
+
+ /* Integrity-check the data length */
+ if ((data_length % entry_size) != 0)
+ {
+ png_warning(png_ptr, "sPLT chunk has bad length");
+ return;
+ }
+
+ dl = (png_int_32)(data_length / entry_size);
+ max_dl = PNG_SIZE_MAX / (sizeof (png_sPLT_entry));
+
+ if (dl > max_dl)
+ {
+ png_warning(png_ptr, "sPLT chunk too long");
+ return;
+ }
+
+ new_palette.nentries = (png_int_32)(data_length / entry_size);
+
+ new_palette.entries = (png_sPLT_entryp)png_malloc_warn(
+ png_ptr, new_palette.nentries * (sizeof (png_sPLT_entry)));
+
+ if (new_palette.entries == NULL)
+ {
+ png_warning(png_ptr, "sPLT chunk requires too much memory");
+ return;
+ }
+
+#ifdef PNG_POINTER_INDEXING_SUPPORTED
+ for (i = 0; i < new_palette.nentries; i++)
+ {
+ pp = new_palette.entries + i;
+
+ if (new_palette.depth == 8)
+ {
+ pp->red = *entry_start++;
+ pp->green = *entry_start++;
+ pp->blue = *entry_start++;
+ pp->alpha = *entry_start++;
+ }
+
+ else
+ {
+ pp->red = png_get_uint_16(entry_start); entry_start += 2;
+ pp->green = png_get_uint_16(entry_start); entry_start += 2;
+ pp->blue = png_get_uint_16(entry_start); entry_start += 2;
+ pp->alpha = png_get_uint_16(entry_start); entry_start += 2;
+ }
+
+ pp->frequency = png_get_uint_16(entry_start); entry_start += 2;
+ }
+#else
+ pp = new_palette.entries;
+
+ for (i = 0; i < new_palette.nentries; i++)
+ {
+
+ if (new_palette.depth == 8)
+ {
+ pp[i].red = *entry_start++;
+ pp[i].green = *entry_start++;
+ pp[i].blue = *entry_start++;
+ pp[i].alpha = *entry_start++;
+ }
+
+ else
+ {
+ pp[i].red = png_get_uint_16(entry_start); entry_start += 2;
+ pp[i].green = png_get_uint_16(entry_start); entry_start += 2;
+ pp[i].blue = png_get_uint_16(entry_start); entry_start += 2;
+ pp[i].alpha = png_get_uint_16(entry_start); entry_start += 2;
+ }
+
+ pp[i].frequency = png_get_uint_16(entry_start); entry_start += 2;
+ }
+#endif
+
+ /* Discard all chunk data except the name and stash that */
+ new_palette.name = (png_charp)buffer;
+
+ png_set_sPLT(png_ptr, info_ptr, &new_palette, 1);
+
+ png_free(png_ptr, new_palette.entries);
+}
+#endif /* READ_sPLT */
+
+#ifdef PNG_READ_tRNS_SUPPORTED
+void /* PRIVATE */
+png_handle_tRNS(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
+{
+ png_byte readbuf[PNG_MAX_PALETTE_LENGTH];
+
+ png_debug(1, "in png_handle_tRNS");
+
+ if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
+ png_chunk_error(png_ptr, "missing IHDR");
+
+ else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
+ {
+ png_crc_finish(png_ptr, length);
+ png_chunk_benign_error(png_ptr, "out of place");
+ return;
+ }
+
+ else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_tRNS) != 0)
+ {
+ png_crc_finish(png_ptr, length);
+ png_chunk_benign_error(png_ptr, "duplicate");
+ return;
+ }
+
+ if (png_ptr->color_type == PNG_COLOR_TYPE_GRAY)
+ {
+ png_byte buf[2];
+
+ if (length != 2)
+ {
+ png_crc_finish(png_ptr, length);
+ png_chunk_benign_error(png_ptr, "invalid");
+ return;
+ }
+
+ png_crc_read(png_ptr, buf, 2);
+ png_ptr->num_trans = 1;
+ png_ptr->trans_color.gray = png_get_uint_16(buf);
+ }
+
+ else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB)
+ {
+ png_byte buf[6];
+
+ if (length != 6)
+ {
+ png_crc_finish(png_ptr, length);
+ png_chunk_benign_error(png_ptr, "invalid");
+ return;
+ }
+
+ png_crc_read(png_ptr, buf, length);
+ png_ptr->num_trans = 1;
+ png_ptr->trans_color.red = png_get_uint_16(buf);
+ png_ptr->trans_color.green = png_get_uint_16(buf + 2);
+ png_ptr->trans_color.blue = png_get_uint_16(buf + 4);
+ }
+
+ else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
+ {
+ if ((png_ptr->mode & PNG_HAVE_PLTE) == 0)
+ {
+ /* TODO: is this actually an error in the ISO spec? */
+ png_crc_finish(png_ptr, length);
+ png_chunk_benign_error(png_ptr, "out of place");
+ return;
+ }
+
+ if (length > png_ptr->num_palette || length > PNG_MAX_PALETTE_LENGTH ||
+ length == 0)
+ {
+ png_crc_finish(png_ptr, length);
+ png_chunk_benign_error(png_ptr, "invalid");
+ return;
+ }
+
+ png_crc_read(png_ptr, readbuf, length);
+ png_ptr->num_trans = (png_uint_16)length;
+ }
+
+ else
+ {
+ png_crc_finish(png_ptr, length);
+ png_chunk_benign_error(png_ptr, "invalid with alpha channel");
+ return;
+ }
+
+ if (png_crc_finish(png_ptr, 0) != 0)
+ {
+ png_ptr->num_trans = 0;
+ return;
+ }
+
+ /* TODO: this is a horrible side effect in the palette case because the
+ * png_struct ends up with a pointer to the tRNS buffer owned by the
+ * png_info. Fix this.
+ */
+ png_set_tRNS(png_ptr, info_ptr, readbuf, png_ptr->num_trans,
+ &(png_ptr->trans_color));
+}
+#endif
+
+#ifdef PNG_READ_bKGD_SUPPORTED
+void /* PRIVATE */
+png_handle_bKGD(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
+{
+ unsigned int truelen;
+ png_byte buf[6];
+ png_color_16 background;
+
+ png_debug(1, "in png_handle_bKGD");
+
+ if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
+ png_chunk_error(png_ptr, "missing IHDR");
+
+ else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0 ||
+ (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
+ (png_ptr->mode & PNG_HAVE_PLTE) == 0))
+ {
+ png_crc_finish(png_ptr, length);
+ png_chunk_benign_error(png_ptr, "out of place");
+ return;
+ }
+
+ else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_bKGD) != 0)
+ {
+ png_crc_finish(png_ptr, length);
+ png_chunk_benign_error(png_ptr, "duplicate");
+ return;
+ }
+
+ if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
+ truelen = 1;
+
+ else if ((png_ptr->color_type & PNG_COLOR_MASK_COLOR) != 0)
+ truelen = 6;
+
+ else
+ truelen = 2;
+
+ if (length != truelen)
+ {
+ png_crc_finish(png_ptr, length);
+ png_chunk_benign_error(png_ptr, "invalid");
+ return;
+ }
+
+ png_crc_read(png_ptr, buf, truelen);
+
+ if (png_crc_finish(png_ptr, 0) != 0)
+ return;
+
+ /* We convert the index value into RGB components so that we can allow
+ * arbitrary RGB values for background when we have transparency, and
+ * so it is easy to determine the RGB values of the background color
+ * from the info_ptr struct.
+ */
+ if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
+ {
+ background.index = buf[0];
+
+ if (info_ptr != NULL && info_ptr->num_palette != 0)
+ {
+ if (buf[0] >= info_ptr->num_palette)
+ {
+ png_chunk_benign_error(png_ptr, "invalid index");
+ return;
+ }
+
+ background.red = (png_uint_16)png_ptr->palette[buf[0]].red;
+ background.green = (png_uint_16)png_ptr->palette[buf[0]].green;
+ background.blue = (png_uint_16)png_ptr->palette[buf[0]].blue;
+ }
+
+ else
+ background.red = background.green = background.blue = 0;
+
+ background.gray = 0;
+ }
+
+ else if ((png_ptr->color_type & PNG_COLOR_MASK_COLOR) == 0) /* GRAY */
+ {
+ background.index = 0;
+ background.red =
+ background.green =
+ background.blue =
+ background.gray = png_get_uint_16(buf);
+ }
+
+ else
+ {
+ background.index = 0;
+ background.red = png_get_uint_16(buf);
+ background.green = png_get_uint_16(buf + 2);
+ background.blue = png_get_uint_16(buf + 4);
+ background.gray = 0;
+ }
+
+ png_set_bKGD(png_ptr, info_ptr, &background);
+}
+#endif
+
+#ifdef PNG_READ_hIST_SUPPORTED
+void /* PRIVATE */
+png_handle_hIST(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
+{
+ unsigned int num, i;
+ png_uint_16 readbuf[PNG_MAX_PALETTE_LENGTH];
+
+ png_debug(1, "in png_handle_hIST");
+
+ if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
+ png_chunk_error(png_ptr, "missing IHDR");
+
+ else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0 ||
+ (png_ptr->mode & PNG_HAVE_PLTE) == 0)
+ {
+ png_crc_finish(png_ptr, length);
+ png_chunk_benign_error(png_ptr, "out of place");
+ return;
+ }
+
+ else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_hIST) != 0)
+ {
+ png_crc_finish(png_ptr, length);
+ png_chunk_benign_error(png_ptr, "duplicate");
+ return;
+ }
+
+ num = length / 2 ;
+
+ if (num != png_ptr->num_palette || num > PNG_MAX_PALETTE_LENGTH)
+ {
+ png_crc_finish(png_ptr, length);
+ png_chunk_benign_error(png_ptr, "invalid");
+ return;
+ }
+
+ for (i = 0; i < num; i++)
+ {
+ png_byte buf[2];
+
+ png_crc_read(png_ptr, buf, 2);
+ readbuf[i] = png_get_uint_16(buf);
+ }
+
+ if (png_crc_finish(png_ptr, 0) != 0)
+ return;
+
+ png_set_hIST(png_ptr, info_ptr, readbuf);
+}
+#endif
+
+#ifdef PNG_READ_pHYs_SUPPORTED
+void /* PRIVATE */
+png_handle_pHYs(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
+{
+ png_byte buf[9];
+ png_uint_32 res_x, res_y;
+ int unit_type;
+
+ png_debug(1, "in png_handle_pHYs");
+
+ if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
+ png_chunk_error(png_ptr, "missing IHDR");
+
+ else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
+ {
+ png_crc_finish(png_ptr, length);
+ png_chunk_benign_error(png_ptr, "out of place");
+ return;
+ }
+
+ else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_pHYs) != 0)
+ {
+ png_crc_finish(png_ptr, length);
+ png_chunk_benign_error(png_ptr, "duplicate");
+ return;
+ }
+
+ if (length != 9)
+ {
+ png_crc_finish(png_ptr, length);
+ png_chunk_benign_error(png_ptr, "invalid");
+ return;
+ }
+
+ png_crc_read(png_ptr, buf, 9);
+
+ if (png_crc_finish(png_ptr, 0) != 0)
+ return;
+
+ res_x = png_get_uint_32(buf);
+ res_y = png_get_uint_32(buf + 4);
+ unit_type = buf[8];
+ png_set_pHYs(png_ptr, info_ptr, res_x, res_y, unit_type);
+}
+#endif
+
+#ifdef PNG_READ_oFFs_SUPPORTED
+void /* PRIVATE */
+png_handle_oFFs(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
+{
+ png_byte buf[9];
+ png_int_32 offset_x, offset_y;
+ int unit_type;
+
+ png_debug(1, "in png_handle_oFFs");
+
+ if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
+ png_chunk_error(png_ptr, "missing IHDR");
+
+ else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
+ {
+ png_crc_finish(png_ptr, length);
+ png_chunk_benign_error(png_ptr, "out of place");
+ return;
+ }
+
+ else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_oFFs) != 0)
+ {
+ png_crc_finish(png_ptr, length);
+ png_chunk_benign_error(png_ptr, "duplicate");
+ return;
+ }
+
+ if (length != 9)
+ {
+ png_crc_finish(png_ptr, length);
+ png_chunk_benign_error(png_ptr, "invalid");
+ return;
+ }
+
+ png_crc_read(png_ptr, buf, 9);
+
+ if (png_crc_finish(png_ptr, 0) != 0)
+ return;
+
+ offset_x = png_get_int_32(buf);
+ offset_y = png_get_int_32(buf + 4);
+ unit_type = buf[8];
+ png_set_oFFs(png_ptr, info_ptr, offset_x, offset_y, unit_type);
+}
+#endif
+
+#ifdef PNG_READ_pCAL_SUPPORTED
+/* Read the pCAL chunk (described in the PNG Extensions document) */
+void /* PRIVATE */
+png_handle_pCAL(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
+{
+ png_int_32 X0, X1;
+ png_byte type, nparams;
+ png_bytep buffer, buf, units, endptr;
+ png_charpp params;
+ int i;
+
+ png_debug(1, "in png_handle_pCAL");
+
+ if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
+ png_chunk_error(png_ptr, "missing IHDR");
+
+ else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
+ {
+ png_crc_finish(png_ptr, length);
+ png_chunk_benign_error(png_ptr, "out of place");
+ return;
+ }
+
+ else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_pCAL) != 0)
+ {
+ png_crc_finish(png_ptr, length);
+ png_chunk_benign_error(png_ptr, "duplicate");
+ return;
+ }
+
+ png_debug1(2, "Allocating and reading pCAL chunk data (%u bytes)",
+ length + 1);
+
+ buffer = png_read_buffer(png_ptr, length+1, 2/*silent*/);
+
+ if (buffer == NULL)
+ {
+ png_crc_finish(png_ptr, length);
+ png_chunk_benign_error(png_ptr, "out of memory");
+ return;
+ }
+
+ png_crc_read(png_ptr, buffer, length);
+
+ if (png_crc_finish(png_ptr, 0) != 0)
+ return;
+
+ buffer[length] = 0; /* Null terminate the last string */
+
+ png_debug(3, "Finding end of pCAL purpose string");
+ for (buf = buffer; *buf; buf++)
+ /* Empty loop */ ;
+
+ endptr = buffer + length;
+
+ /* We need to have at least 12 bytes after the purpose string
+ * in order to get the parameter information.
+ */
+ if (endptr <= buf + 12)
+ {
+ png_chunk_benign_error(png_ptr, "invalid");
+ return;
+ }
+
+ png_debug(3, "Reading pCAL X0, X1, type, nparams, and units");
+ X0 = png_get_int_32((png_bytep)buf+1);
+ X1 = png_get_int_32((png_bytep)buf+5);
+ type = buf[9];
+ nparams = buf[10];
+ units = buf + 11;
+
+ png_debug(3, "Checking pCAL equation type and number of parameters");
+ /* Check that we have the right number of parameters for known
+ * equation types.
+ */
+ if ((type == PNG_EQUATION_LINEAR && nparams != 2) ||
+ (type == PNG_EQUATION_BASE_E && nparams != 3) ||
+ (type == PNG_EQUATION_ARBITRARY && nparams != 3) ||
+ (type == PNG_EQUATION_HYPERBOLIC && nparams != 4))
+ {
+ png_chunk_benign_error(png_ptr, "invalid parameter count");
+ return;
+ }
+
+ else if (type >= PNG_EQUATION_LAST)
+ {
+ png_chunk_benign_error(png_ptr, "unrecognized equation type");
+ }
+
+ for (buf = units; *buf; buf++)
+ /* Empty loop to move past the units string. */ ;
+
+ png_debug(3, "Allocating pCAL parameters array");
+
+ params = png_voidcast(png_charpp, png_malloc_warn(png_ptr,
+ nparams * (sizeof (png_charp))));
+
+ if (params == NULL)
+ {
+ png_chunk_benign_error(png_ptr, "out of memory");
+ return;
+ }
+
+ /* Get pointers to the start of each parameter string. */
+ for (i = 0; i < nparams; i++)
+ {
+ buf++; /* Skip the null string terminator from previous parameter. */
+
+ png_debug1(3, "Reading pCAL parameter %d", i);
+
+ for (params[i] = (png_charp)buf; buf <= endptr && *buf != 0; buf++)
+ /* Empty loop to move past each parameter string */ ;
+
+ /* Make sure we haven't run out of data yet */
+ if (buf > endptr)
+ {
+ png_free(png_ptr, params);
+ png_chunk_benign_error(png_ptr, "invalid data");
+ return;
+ }
+ }
+
+ png_set_pCAL(png_ptr, info_ptr, (png_charp)buffer, X0, X1, type, nparams,
+ (png_charp)units, params);
+
+ png_free(png_ptr, params);
+}
+#endif
+
+#ifdef PNG_READ_sCAL_SUPPORTED
+/* Read the sCAL chunk */
+void /* PRIVATE */
+png_handle_sCAL(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
+{
+ png_bytep buffer;
+ png_size_t i;
+ int state;
+
+ png_debug(1, "in png_handle_sCAL");
+
+ if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
+ png_chunk_error(png_ptr, "missing IHDR");
+
+ else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
+ {
+ png_crc_finish(png_ptr, length);
+ png_chunk_benign_error(png_ptr, "out of place");
+ return;
+ }
+
+ else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_sCAL) != 0)
+ {
+ png_crc_finish(png_ptr, length);
+ png_chunk_benign_error(png_ptr, "duplicate");
+ return;
+ }
+
+ /* Need unit type, width, \0, height: minimum 4 bytes */
+ else if (length < 4)
+ {
+ png_crc_finish(png_ptr, length);
+ png_chunk_benign_error(png_ptr, "invalid");
+ return;
+ }
+
+ png_debug1(2, "Allocating and reading sCAL chunk data (%u bytes)",
+ length + 1);
+
+ buffer = png_read_buffer(png_ptr, length+1, 2/*silent*/);
+
+ if (buffer == NULL)
+ {
+ png_chunk_benign_error(png_ptr, "out of memory");
+ png_crc_finish(png_ptr, length);
+ return;
+ }
+
+ png_crc_read(png_ptr, buffer, length);
+ buffer[length] = 0; /* Null terminate the last string */
+
+ if (png_crc_finish(png_ptr, 0) != 0)
+ return;
+
+ /* Validate the unit. */
+ if (buffer[0] != 1 && buffer[0] != 2)
+ {
+ png_chunk_benign_error(png_ptr, "invalid unit");
+ return;
+ }
+
+ /* Validate the ASCII numbers, need two ASCII numbers separated by
+ * a '\0' and they need to fit exactly in the chunk data.
+ */
+ i = 1;
+ state = 0;
+
+ if (png_check_fp_number((png_const_charp)buffer, length, &state, &i) == 0 ||
+ i >= length || buffer[i++] != 0)
+ png_chunk_benign_error(png_ptr, "bad width format");
+
+ else if (PNG_FP_IS_POSITIVE(state) == 0)
+ png_chunk_benign_error(png_ptr, "non-positive width");
+
+ else
+ {
+ png_size_t heighti = i;
+
+ state = 0;
+ if (png_check_fp_number((png_const_charp)buffer, length,
+ &state, &i) == 0 || i != length)
+ png_chunk_benign_error(png_ptr, "bad height format");
+
+ else if (PNG_FP_IS_POSITIVE(state) == 0)
+ png_chunk_benign_error(png_ptr, "non-positive height");
+
+ else
+ /* This is the (only) success case. */
+ png_set_sCAL_s(png_ptr, info_ptr, buffer[0],
+ (png_charp)buffer+1, (png_charp)buffer+heighti);
+ }
+}
+#endif
+
+#ifdef PNG_READ_tIME_SUPPORTED
+void /* PRIVATE */
+png_handle_tIME(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
+{
+ png_byte buf[7];
+ png_time mod_time;
+
+ png_debug(1, "in png_handle_tIME");
+
+ if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
+ png_chunk_error(png_ptr, "missing IHDR");
+
+ else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_tIME) != 0)
+ {
+ png_crc_finish(png_ptr, length);
+ png_chunk_benign_error(png_ptr, "duplicate");
+ return;
+ }
+
+ if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
+ png_ptr->mode |= PNG_AFTER_IDAT;
+
+ if (length != 7)
+ {
+ png_crc_finish(png_ptr, length);
+ png_chunk_benign_error(png_ptr, "invalid");
+ return;
+ }
+
+ png_crc_read(png_ptr, buf, 7);
+
+ if (png_crc_finish(png_ptr, 0) != 0)
+ return;
+
+ mod_time.second = buf[6];
+ mod_time.minute = buf[5];
+ mod_time.hour = buf[4];
+ mod_time.day = buf[3];
+ mod_time.month = buf[2];
+ mod_time.year = png_get_uint_16(buf);
+
+ png_set_tIME(png_ptr, info_ptr, &mod_time);
+}
+#endif
+
+#ifdef PNG_READ_tEXt_SUPPORTED
+/* Note: this does not properly handle chunks that are > 64K under DOS */
+void /* PRIVATE */
+png_handle_tEXt(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
+{
+ png_text text_info;
+ png_bytep buffer;
+ png_charp key;
+ png_charp text;
+ png_uint_32 skip = 0;
+
+ png_debug(1, "in png_handle_tEXt");
+
+#ifdef PNG_USER_LIMITS_SUPPORTED
+ if (png_ptr->user_chunk_cache_max != 0)
+ {
+ if (png_ptr->user_chunk_cache_max == 1)
+ {
+ png_crc_finish(png_ptr, length);
+ return;
+ }
+
+ if (--png_ptr->user_chunk_cache_max == 1)
+ {
+ png_crc_finish(png_ptr, length);
+ png_chunk_benign_error(png_ptr, "no space in chunk cache");
+ return;
+ }
+ }
+#endif
+
+ if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
+ png_chunk_error(png_ptr, "missing IHDR");
+
+ if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
+ png_ptr->mode |= PNG_AFTER_IDAT;
+
+#ifdef PNG_MAX_MALLOC_64K
+ if (length > 65535U)
+ {
+ png_crc_finish(png_ptr, length);
+ png_chunk_benign_error(png_ptr, "too large to fit in memory");
+ return;
+ }
+#endif
+
+ buffer = png_read_buffer(png_ptr, length+1, 1/*warn*/);
+
+ if (buffer == NULL)
+ {
+ png_chunk_benign_error(png_ptr, "out of memory");
+ return;
+ }
+
+ png_crc_read(png_ptr, buffer, length);
+
+ if (png_crc_finish(png_ptr, skip) != 0)
+ return;
+
+ key = (png_charp)buffer;
+ key[length] = 0;
+
+ for (text = key; *text; text++)
+ /* Empty loop to find end of key */ ;
+
+ if (text != key + length)
+ text++;
+
+ text_info.compression = PNG_TEXT_COMPRESSION_NONE;
+ text_info.key = key;
+ text_info.lang = NULL;
+ text_info.lang_key = NULL;
+ text_info.itxt_length = 0;
+ text_info.text = text;
+ text_info.text_length = strlen(text);
+
+ if (png_set_text_2(png_ptr, info_ptr, &text_info, 1) != 0)
+ png_warning(png_ptr, "Insufficient memory to process text chunk");
+}
+#endif
+
+#ifdef PNG_READ_zTXt_SUPPORTED
+/* Note: this does not correctly handle chunks that are > 64K under DOS */
+void /* PRIVATE */
+png_handle_zTXt(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
+{
+ png_const_charp errmsg = NULL;
+ png_bytep buffer;
+ png_uint_32 keyword_length;
+
+ png_debug(1, "in png_handle_zTXt");
+
+#ifdef PNG_USER_LIMITS_SUPPORTED
+ if (png_ptr->user_chunk_cache_max != 0)
+ {
+ if (png_ptr->user_chunk_cache_max == 1)
+ {
+ png_crc_finish(png_ptr, length);
+ return;
+ }
+
+ if (--png_ptr->user_chunk_cache_max == 1)
+ {
+ png_crc_finish(png_ptr, length);
+ png_chunk_benign_error(png_ptr, "no space in chunk cache");
+ return;
+ }
+ }
+#endif
+
+ if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
+ png_chunk_error(png_ptr, "missing IHDR");
+
+ if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
+ png_ptr->mode |= PNG_AFTER_IDAT;
+
+ buffer = png_read_buffer(png_ptr, length, 2/*silent*/);
+
+ if (buffer == NULL)
+ {
+ png_crc_finish(png_ptr, length);
+ png_chunk_benign_error(png_ptr, "out of memory");
+ return;
+ }
+
+ png_crc_read(png_ptr, buffer, length);
+
+ if (png_crc_finish(png_ptr, 0) != 0)
+ return;
+
+ /* TODO: also check that the keyword contents match the spec! */
+ for (keyword_length = 0;
+ keyword_length < length && buffer[keyword_length] != 0;
+ ++keyword_length)
+ /* Empty loop to find end of name */ ;
+
+ if (keyword_length > 79 || keyword_length < 1)
+ errmsg = "bad keyword";
+
+ /* zTXt must have some LZ data after the keyword, although it may expand to
+ * zero bytes; we need a '\0' at the end of the keyword, the compression type
+ * then the LZ data:
+ */
+ else if (keyword_length + 3 > length)
+ errmsg = "truncated";
+
+ else if (buffer[keyword_length+1] != PNG_COMPRESSION_TYPE_BASE)
+ errmsg = "unknown compression type";
+
+ else
+ {
+ png_alloc_size_t uncompressed_length = PNG_SIZE_MAX;
+
+ /* TODO: at present png_decompress_chunk imposes a single application
+ * level memory limit, this should be split to different values for iCCP
+ * and text chunks.
+ */
+ if (png_decompress_chunk(png_ptr, length, keyword_length+2,
+ &uncompressed_length, 1/*terminate*/) == Z_STREAM_END)
+ {
+ png_text text;
+
+ /* It worked; png_ptr->read_buffer now looks like a tEXt chunk except
+ * for the extra compression type byte and the fact that it isn't
+ * necessarily '\0' terminated.
+ */
+ buffer = png_ptr->read_buffer;
+ buffer[uncompressed_length+(keyword_length+2)] = 0;
+
+ text.compression = PNG_TEXT_COMPRESSION_zTXt;
+ text.key = (png_charp)buffer;
+ text.text = (png_charp)(buffer + keyword_length+2);
+ text.text_length = uncompressed_length;
+ text.itxt_length = 0;
+ text.lang = NULL;
+ text.lang_key = NULL;
+
+ if (png_set_text_2(png_ptr, info_ptr, &text, 1) != 0)
+ errmsg = "insufficient memory";
+ }
+
+ else
+ errmsg = png_ptr->zstream.msg;
+ }
+
+ if (errmsg != NULL)
+ png_chunk_benign_error(png_ptr, errmsg);
+}
+#endif
+
+#ifdef PNG_READ_iTXt_SUPPORTED
+/* Note: this does not correctly handle chunks that are > 64K under DOS */
+void /* PRIVATE */
+png_handle_iTXt(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length)
+{
+ png_const_charp errmsg = NULL;
+ png_bytep buffer;
+ png_uint_32 prefix_length;
+
+ png_debug(1, "in png_handle_iTXt");
+
+#ifdef PNG_USER_LIMITS_SUPPORTED
+ if (png_ptr->user_chunk_cache_max != 0)
+ {
+ if (png_ptr->user_chunk_cache_max == 1)
+ {
+ png_crc_finish(png_ptr, length);
+ return;
+ }
+
+ if (--png_ptr->user_chunk_cache_max == 1)
+ {
+ png_crc_finish(png_ptr, length);
+ png_chunk_benign_error(png_ptr, "no space in chunk cache");
+ return;
+ }
+ }
+#endif
+
+ if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
+ png_chunk_error(png_ptr, "missing IHDR");
+
+ if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
+ png_ptr->mode |= PNG_AFTER_IDAT;
+
+ buffer = png_read_buffer(png_ptr, length+1, 1/*warn*/);
+
+ if (buffer == NULL)
+ {
+ png_crc_finish(png_ptr, length);
+ png_chunk_benign_error(png_ptr, "out of memory");
+ return;
+ }
+
+ png_crc_read(png_ptr, buffer, length);
+
+ if (png_crc_finish(png_ptr, 0) != 0)
+ return;
+
+ /* First the keyword. */
+ for (prefix_length=0;
+ prefix_length < length && buffer[prefix_length] != 0;
+ ++prefix_length)
+ /* Empty loop */ ;
+
+ /* Perform a basic check on the keyword length here. */
+ if (prefix_length > 79 || prefix_length < 1)
+ errmsg = "bad keyword";
+
+ /* Expect keyword, compression flag, compression type, language, translated
+ * keyword (both may be empty but are 0 terminated) then the text, which may
+ * be empty.
+ */
+ else if (prefix_length + 5 > length)
+ errmsg = "truncated";
+
+ else if (buffer[prefix_length+1] == 0 ||
+ (buffer[prefix_length+1] == 1 &&
+ buffer[prefix_length+2] == PNG_COMPRESSION_TYPE_BASE))
+ {
+ int compressed = buffer[prefix_length+1] != 0;
+ png_uint_32 language_offset, translated_keyword_offset;
+ png_alloc_size_t uncompressed_length = 0;
+
+ /* Now the language tag */
+ prefix_length += 3;
+ language_offset = prefix_length;
+
+ for (; prefix_length < length && buffer[prefix_length] != 0;
+ ++prefix_length)
+ /* Empty loop */ ;
+
+ /* WARNING: the length may be invalid here, this is checked below. */
+ translated_keyword_offset = ++prefix_length;
+
+ for (; prefix_length < length && buffer[prefix_length] != 0;
+ ++prefix_length)
+ /* Empty loop */ ;
+
+ /* prefix_length should now be at the trailing '\0' of the translated
+ * keyword, but it may already be over the end. None of this arithmetic
+ * can overflow because chunks are at most 2^31 bytes long, but on 16-bit
+ * systems the available allocation may overflow.
+ */
+ ++prefix_length;
+
+ if (compressed == 0 && prefix_length <= length)
+ uncompressed_length = length - prefix_length;
+
+ else if (compressed != 0 && prefix_length < length)
+ {
+ uncompressed_length = PNG_SIZE_MAX;
+
+ /* TODO: at present png_decompress_chunk imposes a single application
+ * level memory limit, this should be split to different values for
+ * iCCP and text chunks.
+ */
+ if (png_decompress_chunk(png_ptr, length, prefix_length,
+ &uncompressed_length, 1/*terminate*/) == Z_STREAM_END)
+ buffer = png_ptr->read_buffer;
+
+ else
+ errmsg = png_ptr->zstream.msg;
+ }
+
+ else
+ errmsg = "truncated";
+
+ if (errmsg == NULL)
+ {
+ png_text text;
+
+ buffer[uncompressed_length+prefix_length] = 0;
+
+ if (compressed == 0)
+ text.compression = PNG_ITXT_COMPRESSION_NONE;
+
+ else
+ text.compression = PNG_ITXT_COMPRESSION_zTXt;
+
+ text.key = (png_charp)buffer;
+ text.lang = (png_charp)buffer + language_offset;
+ text.lang_key = (png_charp)buffer + translated_keyword_offset;
+ text.text = (png_charp)buffer + prefix_length;
+ text.text_length = 0;
+ text.itxt_length = uncompressed_length;
+
+ if (png_set_text_2(png_ptr, info_ptr, &text, 1) != 0)
+ errmsg = "insufficient memory";
+ }
+ }
+
+ else
+ errmsg = "bad compression info";
+
+ if (errmsg != NULL)
+ png_chunk_benign_error(png_ptr, errmsg);
+}
+#endif
+
+#ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED
+/* Utility function for png_handle_unknown; set up png_ptr::unknown_chunk */
+static int
+png_cache_unknown_chunk(png_structrp png_ptr, png_uint_32 length)
+{
+ png_alloc_size_t limit = PNG_SIZE_MAX;
+
+ if (png_ptr->unknown_chunk.data != NULL)
+ {
+ png_free(png_ptr, png_ptr->unknown_chunk.data);
+ png_ptr->unknown_chunk.data = NULL;
+ }
+
+# ifdef PNG_SET_CHUNK_MALLOC_LIMIT_SUPPORTED
+ if (png_ptr->user_chunk_malloc_max > 0 &&
+ png_ptr->user_chunk_malloc_max < limit)
+ limit = png_ptr->user_chunk_malloc_max;
+
+# elif PNG_USER_CHUNK_MALLOC_MAX > 0
+ if (PNG_USER_CHUNK_MALLOC_MAX < limit)
+ limit = PNG_USER_CHUNK_MALLOC_MAX;
+# endif
+
+ if (length <= limit)
+ {
+ PNG_CSTRING_FROM_CHUNK(png_ptr->unknown_chunk.name, png_ptr->chunk_name);
+ /* The following is safe because of the PNG_SIZE_MAX init above */
+ png_ptr->unknown_chunk.size = (png_size_t)length/*SAFE*/;
+ /* 'mode' is a flag array, only the bottom four bits matter here */
+ png_ptr->unknown_chunk.location = (png_byte)png_ptr->mode/*SAFE*/;
+
+ if (length == 0)
+ png_ptr->unknown_chunk.data = NULL;
+
+ else
+ {
+ /* Do a 'warn' here - it is handled below. */
+ png_ptr->unknown_chunk.data = png_voidcast(png_bytep,
+ png_malloc_warn(png_ptr, length));
+ }
+ }
+
+ if (png_ptr->unknown_chunk.data == NULL && length > 0)
+ {
+ /* This is benign because we clean up correctly */
+ png_crc_finish(png_ptr, length);
+ png_chunk_benign_error(png_ptr, "unknown chunk exceeds memory limits");
+ return 0;
+ }
+
+ else
+ {
+ if (length > 0)
+ png_crc_read(png_ptr, png_ptr->unknown_chunk.data, length);
+ png_crc_finish(png_ptr, 0);
+ return 1;
+ }
+}
+#endif /* READ_UNKNOWN_CHUNKS */
+
+/* Handle an unknown, or known but disabled, chunk */
+void /* PRIVATE */
+png_handle_unknown(png_structrp png_ptr, png_inforp info_ptr,
+ png_uint_32 length, int keep)
+{
+ int handled = 0; /* the chunk was handled */
+
+ png_debug(1, "in png_handle_unknown");
+
+#ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED
+ /* NOTE: this code is based on the code in libpng-1.4.12 except for fixing
+ * the bug which meant that setting a non-default behavior for a specific
+ * chunk would be ignored (the default was always used unless a user
+ * callback was installed).
+ *
+ * 'keep' is the value from the png_chunk_unknown_handling, the setting for
+ * this specific chunk_name, if PNG_HANDLE_AS_UNKNOWN_SUPPORTED, if not it
+ * will always be PNG_HANDLE_CHUNK_AS_DEFAULT and it needs to be set here.
+ * This is just an optimization to avoid multiple calls to the lookup
+ * function.
+ */
+# ifndef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
+# ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
+ keep = png_chunk_unknown_handling(png_ptr, png_ptr->chunk_name);
+# endif
+# endif
+
+ /* One of the following methods will read the chunk or skip it (at least one
+ * of these is always defined because this is the only way to switch on
+ * PNG_READ_UNKNOWN_CHUNKS_SUPPORTED)
+ */
+# ifdef PNG_READ_USER_CHUNKS_SUPPORTED
+ /* The user callback takes precedence over the chunk keep value, but the
+ * keep value is still required to validate a save of a critical chunk.
+ */
+ if (png_ptr->read_user_chunk_fn != NULL)
+ {
+ if (png_cache_unknown_chunk(png_ptr, length) != 0)
+ {
+ /* Callback to user unknown chunk handler */
+ int ret = (*(png_ptr->read_user_chunk_fn))(png_ptr,
+ &png_ptr->unknown_chunk);
+
+ /* ret is:
+ * negative: An error occurred; png_chunk_error will be called.
+ * zero: The chunk was not handled, the chunk will be discarded
+ * unless png_set_keep_unknown_chunks has been used to set
+ * a 'keep' behavior for this particular chunk, in which
+ * case that will be used. A critical chunk will cause an
+ * error at this point unless it is to be saved.
+ * positive: The chunk was handled, libpng will ignore/discard it.
+ */
+ if (ret < 0)
+ png_chunk_error(png_ptr, "error in user chunk");
+
+ else if (ret == 0)
+ {
+ /* If the keep value is 'default' or 'never' override it, but
+ * still error out on critical chunks unless the keep value is
+ * 'always' While this is weird it is the behavior in 1.4.12.
+ * A possible improvement would be to obey the value set for the
+ * chunk, but this would be an API change that would probably
+ * damage some applications.
+ *
+ * The png_app_warning below catches the case that matters, where
+ * the application has not set specific save or ignore for this
+ * chunk or global save or ignore.
+ */
+ if (keep < PNG_HANDLE_CHUNK_IF_SAFE)
+ {
+# ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
+ if (png_ptr->unknown_default < PNG_HANDLE_CHUNK_IF_SAFE)
+ {
+ png_chunk_warning(png_ptr, "Saving unknown chunk:");
+ png_app_warning(png_ptr,
+ "forcing save of an unhandled chunk;"
+ " please call png_set_keep_unknown_chunks");
+ /* with keep = PNG_HANDLE_CHUNK_IF_SAFE */
+ }
+# endif
+ keep = PNG_HANDLE_CHUNK_IF_SAFE;
+ }
+ }
+
+ else /* chunk was handled */
+ {
+ handled = 1;
+ /* Critical chunks can be safely discarded at this point. */
+ keep = PNG_HANDLE_CHUNK_NEVER;
+ }
+ }
+
+ else
+ keep = PNG_HANDLE_CHUNK_NEVER; /* insufficient memory */
+ }
+
+ else
+ /* Use the SAVE_UNKNOWN_CHUNKS code or skip the chunk */
+# endif /* READ_USER_CHUNKS */
+
+# ifdef PNG_SAVE_UNKNOWN_CHUNKS_SUPPORTED
+ {
+ /* keep is currently just the per-chunk setting, if there was no
+ * setting change it to the global default now (not that this may
+ * still be AS_DEFAULT) then obtain the cache of the chunk if required,
+ * if not simply skip the chunk.
+ */
+ if (keep == PNG_HANDLE_CHUNK_AS_DEFAULT)
+ keep = png_ptr->unknown_default;
+
+ if (keep == PNG_HANDLE_CHUNK_ALWAYS ||
+ (keep == PNG_HANDLE_CHUNK_IF_SAFE &&
+ PNG_CHUNK_ANCILLARY(png_ptr->chunk_name)))
+ {
+ if (png_cache_unknown_chunk(png_ptr, length) == 0)
+ keep = PNG_HANDLE_CHUNK_NEVER;
+ }
+
+ else
+ png_crc_finish(png_ptr, length);
+ }
+# else
+# ifndef PNG_READ_USER_CHUNKS_SUPPORTED
+# error no method to support READ_UNKNOWN_CHUNKS
+# endif
+
+ {
+ /* If here there is no read callback pointer set and no support is
+ * compiled in to just save the unknown chunks, so simply skip this
+ * chunk. If 'keep' is something other than AS_DEFAULT or NEVER then
+ * the app has erroneously asked for unknown chunk saving when there
+ * is no support.
+ */
+ if (keep > PNG_HANDLE_CHUNK_NEVER)
+ png_app_error(png_ptr, "no unknown chunk support available");
+
+ png_crc_finish(png_ptr, length);
+ }
+# endif
+
+# ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED
+ /* Now store the chunk in the chunk list if appropriate, and if the limits
+ * permit it.
+ */
+ if (keep == PNG_HANDLE_CHUNK_ALWAYS ||
+ (keep == PNG_HANDLE_CHUNK_IF_SAFE &&
+ PNG_CHUNK_ANCILLARY(png_ptr->chunk_name)))
+ {
+# ifdef PNG_USER_LIMITS_SUPPORTED
+ switch (png_ptr->user_chunk_cache_max)
+ {
+ case 2:
+ png_ptr->user_chunk_cache_max = 1;
+ png_chunk_benign_error(png_ptr, "no space in chunk cache");
+ /* FALL THROUGH */
+ case 1:
+ /* NOTE: prior to 1.6.0 this case resulted in an unknown critical
+ * chunk being skipped, now there will be a hard error below.
+ */
+ break;
+
+ default: /* not at limit */
+ --(png_ptr->user_chunk_cache_max);
+ /* FALL THROUGH */
+ case 0: /* no limit */
+# endif /* USER_LIMITS */
+ /* Here when the limit isn't reached or when limits are compiled
+ * out; store the chunk.
+ */
+ png_set_unknown_chunks(png_ptr, info_ptr,
+ &png_ptr->unknown_chunk, 1);
+ handled = 1;
+# ifdef PNG_USER_LIMITS_SUPPORTED
+ break;
+ }
+# endif
+ }
+# else /* no store support: the chunk must be handled by the user callback */
+ PNG_UNUSED(info_ptr)
+# endif
+
+ /* Regardless of the error handling below the cached data (if any) can be
+ * freed now. Notice that the data is not freed if there is a png_error, but
+ * it will be freed by destroy_read_struct.
+ */
+ if (png_ptr->unknown_chunk.data != NULL)
+ png_free(png_ptr, png_ptr->unknown_chunk.data);
+ png_ptr->unknown_chunk.data = NULL;
+
+#else /* !PNG_READ_UNKNOWN_CHUNKS_SUPPORTED */
+ /* There is no support to read an unknown chunk, so just skip it. */
+ png_crc_finish(png_ptr, length);
+ PNG_UNUSED(info_ptr)
+ PNG_UNUSED(keep)
+#endif /* !READ_UNKNOWN_CHUNKS */
+
+ /* Check for unhandled critical chunks */
+ if (handled == 0 && PNG_CHUNK_CRITICAL(png_ptr->chunk_name))
+ png_chunk_error(png_ptr, "unhandled critical chunk");
+}
+
+/* This function is called to verify that a chunk name is valid.
+ * This function can't have the "critical chunk check" incorporated
+ * into it, since in the future we will need to be able to call user
+ * functions to handle unknown critical chunks after we check that
+ * the chunk name itself is valid.
+ */
+
+/* Bit hacking: the test for an invalid byte in the 4 byte chunk name is:
+ *
+ * ((c) < 65 || (c) > 122 || ((c) > 90 && (c) < 97))
+ */
+
+void /* PRIVATE */
+png_check_chunk_name(png_structrp png_ptr, png_uint_32 chunk_name)
+{
+ int i;
+
+ png_debug(1, "in png_check_chunk_name");
+
+ for (i=1; i<=4; ++i)
+ {
+ int c = chunk_name & 0xff;
+
+ if (c < 65 || c > 122 || (c > 90 && c < 97))
+ png_chunk_error(png_ptr, "invalid chunk type");
+
+ chunk_name >>= 8;
+ }
+}
+
+/* Combines the row recently read in with the existing pixels in the row. This
+ * routine takes care of alpha and transparency if requested. This routine also
+ * handles the two methods of progressive display of interlaced images,
+ * depending on the 'display' value; if 'display' is true then the whole row
+ * (dp) is filled from the start by replicating the available pixels. If
+ * 'display' is false only those pixels present in the pass are filled in.
+ */
+void /* PRIVATE */
+png_combine_row(png_const_structrp png_ptr, png_bytep dp, int display)
+{
+ unsigned int pixel_depth = png_ptr->transformed_pixel_depth;
+ png_const_bytep sp = png_ptr->row_buf + 1;
+ png_alloc_size_t row_width = png_ptr->width;
+ unsigned int pass = png_ptr->pass;
+ png_bytep end_ptr = 0;
+ png_byte end_byte = 0;
+ unsigned int end_mask;
+
+ png_debug(1, "in png_combine_row");
+
+ /* Added in 1.5.6: it should not be possible to enter this routine until at
+ * least one row has been read from the PNG data and transformed.
+ */
+ if (pixel_depth == 0)
+ png_error(png_ptr, "internal row logic error");
+
+ /* Added in 1.5.4: the pixel depth should match the information returned by
+ * any call to png_read_update_info at this point. Do not continue if we got
+ * this wrong.
+ */
+ if (png_ptr->info_rowbytes != 0 && png_ptr->info_rowbytes !=
+ PNG_ROWBYTES(pixel_depth, row_width))
+ png_error(png_ptr, "internal row size calculation error");
+
+ /* Don't expect this to ever happen: */
+ if (row_width == 0)
+ png_error(png_ptr, "internal row width error");
+
+ /* Preserve the last byte in cases where only part of it will be overwritten,
+ * the multiply below may overflow, we don't care because ANSI-C guarantees
+ * we get the low bits.
+ */
+ end_mask = (pixel_depth * row_width) & 7;
+ if (end_mask != 0)
+ {
+ /* end_ptr == NULL is a flag to say do nothing */
+ end_ptr = dp + PNG_ROWBYTES(pixel_depth, row_width) - 1;
+ end_byte = *end_ptr;
+# ifdef PNG_READ_PACKSWAP_SUPPORTED
+ if ((png_ptr->transformations & PNG_PACKSWAP) != 0)
+ /* little-endian byte */
+ end_mask = 0xff << end_mask;
+
+ else /* big-endian byte */
+# endif
+ end_mask = 0xff >> end_mask;
+ /* end_mask is now the bits to *keep* from the destination row */
+ }
+
+ /* For non-interlaced images this reduces to a memcpy(). A memcpy()
+ * will also happen if interlacing isn't supported or if the application
+ * does not call png_set_interlace_handling(). In the latter cases the
+ * caller just gets a sequence of the unexpanded rows from each interlace
+ * pass.
+ */
+#ifdef PNG_READ_INTERLACING_SUPPORTED
+ if (png_ptr->interlaced != 0 &&
+ (png_ptr->transformations & PNG_INTERLACE) != 0 &&
+ pass < 6 && (display == 0 ||
+ /* The following copies everything for 'display' on passes 0, 2 and 4. */
+ (display == 1 && (pass & 1) != 0)))
+ {
+ /* Narrow images may have no bits in a pass; the caller should handle
+ * this, but this test is cheap:
+ */
+ if (row_width <= PNG_PASS_START_COL(pass))
+ return;
+
+ if (pixel_depth < 8)
+ {
+ /* For pixel depths up to 4 bpp the 8-pixel mask can be expanded to fit
+ * into 32 bits, then a single loop over the bytes using the four byte
+ * values in the 32-bit mask can be used. For the 'display' option the
+ * expanded mask may also not require any masking within a byte. To
+ * make this work the PACKSWAP option must be taken into account - it
+ * simply requires the pixels to be reversed in each byte.
+ *
+ * The 'regular' case requires a mask for each of the first 6 passes,
+ * the 'display' case does a copy for the even passes in the range
+ * 0..6. This has already been handled in the test above.
+ *
+ * The masks are arranged as four bytes with the first byte to use in
+ * the lowest bits (little-endian) regardless of the order (PACKSWAP or
+ * not) of the pixels in each byte.
+ *
+ * NOTE: the whole of this logic depends on the caller of this function
+ * only calling it on rows appropriate to the pass. This function only
+ * understands the 'x' logic; the 'y' logic is handled by the caller.
+ *
+ * The following defines allow generation of compile time constant bit
+ * masks for each pixel depth and each possibility of swapped or not
+ * swapped bytes. Pass 'p' is in the range 0..6; 'x', a pixel index,
+ * is in the range 0..7; and the result is 1 if the pixel is to be
+ * copied in the pass, 0 if not. 'S' is for the sparkle method, 'B'
+ * for the block method.
+ *
+ * With some compilers a compile time expression of the general form:
+ *
+ * (shift >= 32) ? (a >> (shift-32)) : (b >> shift)
+ *
+ * Produces warnings with values of 'shift' in the range 33 to 63
+ * because the right hand side of the ?: expression is evaluated by
+ * the compiler even though it isn't used. Microsoft Visual C (various
+ * versions) and the Intel C compiler are known to do this. To avoid
+ * this the following macros are used in 1.5.6. This is a temporary
+ * solution to avoid destabilizing the code during the release process.
+ */
+# if PNG_USE_COMPILE_TIME_MASKS
+# define PNG_LSR(x,s) ((x)>>((s) & 0x1f))
+# define PNG_LSL(x,s) ((x)<<((s) & 0x1f))
+# else
+# define PNG_LSR(x,s) ((x)>>(s))
+# define PNG_LSL(x,s) ((x)<<(s))
+# endif
+# define S_COPY(p,x) (((p)<4 ? PNG_LSR(0x80088822,(3-(p))*8+(7-(x))) :\
+ PNG_LSR(0xaa55ff00,(7-(p))*8+(7-(x)))) & 1)
+# define B_COPY(p,x) (((p)<4 ? PNG_LSR(0xff0fff33,(3-(p))*8+(7-(x))) :\
+ PNG_LSR(0xff55ff00,(7-(p))*8+(7-(x)))) & 1)
+
+ /* Return a mask for pass 'p' pixel 'x' at depth 'd'. The mask is
+ * little endian - the first pixel is at bit 0 - however the extra
+ * parameter 's' can be set to cause the mask position to be swapped
+ * within each byte, to match the PNG format. This is done by XOR of
+ * the shift with 7, 6 or 4 for bit depths 1, 2 and 4.
+ */
+# define PIXEL_MASK(p,x,d,s) \
+ (PNG_LSL(((PNG_LSL(1U,(d)))-1),(((x)*(d))^((s)?8-(d):0))))
+
+ /* Hence generate the appropriate 'block' or 'sparkle' pixel copy mask.
+ */
+# define S_MASKx(p,x,d,s) (S_COPY(p,x)?PIXEL_MASK(p,x,d,s):0)
+# define B_MASKx(p,x,d,s) (B_COPY(p,x)?PIXEL_MASK(p,x,d,s):0)
+
+ /* Combine 8 of these to get the full mask. For the 1-bpp and 2-bpp
+ * cases the result needs replicating, for the 4-bpp case the above
+ * generates a full 32 bits.
+ */
+# define MASK_EXPAND(m,d) ((m)*((d)==1?0x01010101:((d)==2?0x00010001:1)))
+
+# define S_MASK(p,d,s) MASK_EXPAND(S_MASKx(p,0,d,s) + S_MASKx(p,1,d,s) +\
+ S_MASKx(p,2,d,s) + S_MASKx(p,3,d,s) + S_MASKx(p,4,d,s) +\
+ S_MASKx(p,5,d,s) + S_MASKx(p,6,d,s) + S_MASKx(p,7,d,s), d)
+
+# define B_MASK(p,d,s) MASK_EXPAND(B_MASKx(p,0,d,s) + B_MASKx(p,1,d,s) +\
+ B_MASKx(p,2,d,s) + B_MASKx(p,3,d,s) + B_MASKx(p,4,d,s) +\
+ B_MASKx(p,5,d,s) + B_MASKx(p,6,d,s) + B_MASKx(p,7,d,s), d)
+
+#if PNG_USE_COMPILE_TIME_MASKS
+ /* Utility macros to construct all the masks for a depth/swap
+ * combination. The 's' parameter says whether the format is PNG
+ * (big endian bytes) or not. Only the three odd-numbered passes are
+ * required for the display/block algorithm.
+ */
+# define S_MASKS(d,s) { S_MASK(0,d,s), S_MASK(1,d,s), S_MASK(2,d,s),\
+ S_MASK(3,d,s), S_MASK(4,d,s), S_MASK(5,d,s) }
+
+# define B_MASKS(d,s) { B_MASK(1,d,s), B_MASK(3,d,s), B_MASK(5,d,s) }
+
+# define DEPTH_INDEX(d) ((d)==1?0:((d)==2?1:2))
+
+ /* Hence the pre-compiled masks indexed by PACKSWAP (or not), depth and
+ * then pass:
+ */
+ static PNG_CONST png_uint_32 row_mask[2/*PACKSWAP*/][3/*depth*/][6] =
+ {
+ /* Little-endian byte masks for PACKSWAP */
+ { S_MASKS(1,0), S_MASKS(2,0), S_MASKS(4,0) },
+ /* Normal (big-endian byte) masks - PNG format */
+ { S_MASKS(1,1), S_MASKS(2,1), S_MASKS(4,1) }
+ };
+
+ /* display_mask has only three entries for the odd passes, so index by
+ * pass>>1.
+ */
+ static PNG_CONST png_uint_32 display_mask[2][3][3] =
+ {
+ /* Little-endian byte masks for PACKSWAP */
+ { B_MASKS(1,0), B_MASKS(2,0), B_MASKS(4,0) },
+ /* Normal (big-endian byte) masks - PNG format */
+ { B_MASKS(1,1), B_MASKS(2,1), B_MASKS(4,1) }
+ };
+
+# define MASK(pass,depth,display,png)\
+ ((display)?display_mask[png][DEPTH_INDEX(depth)][pass>>1]:\
+ row_mask[png][DEPTH_INDEX(depth)][pass])
+
+#else /* !PNG_USE_COMPILE_TIME_MASKS */
+ /* This is the runtime alternative: it seems unlikely that this will
+ * ever be either smaller or faster than the compile time approach.
+ */
+# define MASK(pass,depth,display,png)\
+ ((display)?B_MASK(pass,depth,png):S_MASK(pass,depth,png))
+#endif /* !USE_COMPILE_TIME_MASKS */
+
+ /* Use the appropriate mask to copy the required bits. In some cases
+ * the byte mask will be 0 or 0xff; optimize these cases. row_width is
+ * the number of pixels, but the code copies bytes, so it is necessary
+ * to special case the end.
+ */
+ png_uint_32 pixels_per_byte = 8 / pixel_depth;
+ png_uint_32 mask;
+
+# ifdef PNG_READ_PACKSWAP_SUPPORTED
+ if ((png_ptr->transformations & PNG_PACKSWAP) != 0)
+ mask = MASK(pass, pixel_depth, display, 0);
+
+ else
+# endif
+ mask = MASK(pass, pixel_depth, display, 1);
+
+ for (;;)
+ {
+ png_uint_32 m;
+
+ /* It doesn't matter in the following if png_uint_32 has more than
+ * 32 bits because the high bits always match those in m<<24; it is,
+ * however, essential to use OR here, not +, because of this.
+ */
+ m = mask;
+ mask = (m >> 8) | (m << 24); /* rotate right to good compilers */
+ m &= 0xff;
+
+ if (m != 0) /* something to copy */
+ {
+ if (m != 0xff)
+ *dp = (png_byte)((*dp & ~m) | (*sp & m));
+ else
+ *dp = *sp;
+ }
+
+ /* NOTE: this may overwrite the last byte with garbage if the image
+ * is not an exact number of bytes wide; libpng has always done
+ * this.
+ */
+ if (row_width <= pixels_per_byte)
+ break; /* May need to restore part of the last byte */
+
+ row_width -= pixels_per_byte;
+ ++dp;
+ ++sp;
+ }
+ }
+
+ else /* pixel_depth >= 8 */
+ {
+ unsigned int bytes_to_copy, bytes_to_jump;
+
+ /* Validate the depth - it must be a multiple of 8 */
+ if (pixel_depth & 7)
+ png_error(png_ptr, "invalid user transform pixel depth");
+
+ pixel_depth >>= 3; /* now in bytes */
+ row_width *= pixel_depth;
+
+ /* Regardless of pass number the Adam 7 interlace always results in a
+ * fixed number of pixels to copy then to skip. There may be a
+ * different number of pixels to skip at the start though.
+ */
+ {
+ unsigned int offset = PNG_PASS_START_COL(pass) * pixel_depth;
+
+ row_width -= offset;
+ dp += offset;
+ sp += offset;
+ }
+
+ /* Work out the bytes to copy. */
+ if (display != 0)
+ {
+ /* When doing the 'block' algorithm the pixel in the pass gets
+ * replicated to adjacent pixels. This is why the even (0,2,4,6)
+ * passes are skipped above - the entire expanded row is copied.
+ */
+ bytes_to_copy = (1<<((6-pass)>>1)) * pixel_depth;
+
+ /* But don't allow this number to exceed the actual row width. */
+ if (bytes_to_copy > row_width)
+ bytes_to_copy = (unsigned int)/*SAFE*/row_width;
+ }
+
+ else /* normal row; Adam7 only ever gives us one pixel to copy. */
+ bytes_to_copy = pixel_depth;
+
+ /* In Adam7 there is a constant offset between where the pixels go. */
+ bytes_to_jump = PNG_PASS_COL_OFFSET(pass) * pixel_depth;
+
+ /* And simply copy these bytes. Some optimization is possible here,
+ * depending on the value of 'bytes_to_copy'. Special case the low
+ * byte counts, which we know to be frequent.
+ *
+ * Notice that these cases all 'return' rather than 'break' - this
+ * avoids an unnecessary test on whether to restore the last byte
+ * below.
+ */
+ switch (bytes_to_copy)
+ {
+ case 1:
+ for (;;)
+ {
+ *dp = *sp;
+
+ if (row_width <= bytes_to_jump)
+ return;
+
+ dp += bytes_to_jump;
+ sp += bytes_to_jump;
+ row_width -= bytes_to_jump;
+ }
+
+ case 2:
+ /* There is a possibility of a partial copy at the end here; this
+ * slows the code down somewhat.
+ */
+ do
+ {
+ dp[0] = sp[0], dp[1] = sp[1];
+
+ if (row_width <= bytes_to_jump)
+ return;
+
+ sp += bytes_to_jump;
+ dp += bytes_to_jump;
+ row_width -= bytes_to_jump;
+ }
+ while (row_width > 1);
+
+ /* And there can only be one byte left at this point: */
+ *dp = *sp;
+ return;
+
+ case 3:
+ /* This can only be the RGB case, so each copy is exactly one
+ * pixel and it is not necessary to check for a partial copy.
+ */
+ for (;;)
+ {
+ dp[0] = sp[0], dp[1] = sp[1], dp[2] = sp[2];
+
+ if (row_width <= bytes_to_jump)
+ return;
+
+ sp += bytes_to_jump;
+ dp += bytes_to_jump;
+ row_width -= bytes_to_jump;
+ }
+
+ default:
+#if PNG_ALIGN_TYPE != PNG_ALIGN_NONE
+ /* Check for double byte alignment and, if possible, use a
+ * 16-bit copy. Don't attempt this for narrow images - ones that
+ * are less than an interlace panel wide. Don't attempt it for
+ * wide bytes_to_copy either - use the memcpy there.
+ */
+ if (bytes_to_copy < 16 /*else use memcpy*/ &&
+ png_isaligned(dp, png_uint_16) &&
+ png_isaligned(sp, png_uint_16) &&
+ bytes_to_copy % (sizeof (png_uint_16)) == 0 &&
+ bytes_to_jump % (sizeof (png_uint_16)) == 0)
+ {
+ /* Everything is aligned for png_uint_16 copies, but try for
+ * png_uint_32 first.
+ */
+ if (png_isaligned(dp, png_uint_32) != 0 &&
+ png_isaligned(sp, png_uint_32) != 0 &&
+ bytes_to_copy % (sizeof (png_uint_32)) == 0 &&
+ bytes_to_jump % (sizeof (png_uint_32)) == 0)
+ {
+ png_uint_32p dp32 = png_aligncast(png_uint_32p,dp);
+ png_const_uint_32p sp32 = png_aligncastconst(
+ png_const_uint_32p, sp);
+ size_t skip = (bytes_to_jump-bytes_to_copy) /
+ (sizeof (png_uint_32));
+
+ do
+ {
+ size_t c = bytes_to_copy;
+ do
+ {
+ *dp32++ = *sp32++;
+ c -= (sizeof (png_uint_32));
+ }
+ while (c > 0);
+
+ if (row_width <= bytes_to_jump)
+ return;
+
+ dp32 += skip;
+ sp32 += skip;
+ row_width -= bytes_to_jump;
+ }
+ while (bytes_to_copy <= row_width);
+
+ /* Get to here when the row_width truncates the final copy.
+ * There will be 1-3 bytes left to copy, so don't try the
+ * 16-bit loop below.
+ */
+ dp = (png_bytep)dp32;
+ sp = (png_const_bytep)sp32;
+ do
+ *dp++ = *sp++;
+ while (--row_width > 0);
+ return;
+ }
+
+ /* Else do it in 16-bit quantities, but only if the size is
+ * not too large.
+ */
+ else
+ {
+ png_uint_16p dp16 = png_aligncast(png_uint_16p, dp);
+ png_const_uint_16p sp16 = png_aligncastconst(
+ png_const_uint_16p, sp);
+ size_t skip = (bytes_to_jump-bytes_to_copy) /
+ (sizeof (png_uint_16));
+
+ do
+ {
+ size_t c = bytes_to_copy;
+ do
+ {
+ *dp16++ = *sp16++;
+ c -= (sizeof (png_uint_16));
+ }
+ while (c > 0);
+
+ if (row_width <= bytes_to_jump)
+ return;
+
+ dp16 += skip;
+ sp16 += skip;
+ row_width -= bytes_to_jump;
+ }
+ while (bytes_to_copy <= row_width);
+
+ /* End of row - 1 byte left, bytes_to_copy > row_width: */
+ dp = (png_bytep)dp16;
+ sp = (png_const_bytep)sp16;
+ do
+ *dp++ = *sp++;
+ while (--row_width > 0);
+ return;
+ }
+ }
+#endif /* ALIGN_TYPE code */
+
+ /* The true default - use a memcpy: */
+ for (;;)
+ {
+ memcpy(dp, sp, bytes_to_copy);
+
+ if (row_width <= bytes_to_jump)
+ return;
+
+ sp += bytes_to_jump;
+ dp += bytes_to_jump;
+ row_width -= bytes_to_jump;
+ if (bytes_to_copy > row_width)
+ bytes_to_copy = (unsigned int)/*SAFE*/row_width;
+ }
+ }
+
+ /* NOT REACHED*/
+ } /* pixel_depth >= 8 */
+
+ /* Here if pixel_depth < 8 to check 'end_ptr' below. */
+ }
+ else
+#endif /* READ_INTERLACING */
+
+ /* If here then the switch above wasn't used so just memcpy the whole row
+ * from the temporary row buffer (notice that this overwrites the end of the
+ * destination row if it is a partial byte.)
+ */
+ memcpy(dp, sp, PNG_ROWBYTES(pixel_depth, row_width));
+
+ /* Restore the overwritten bits from the last byte if necessary. */
+ if (end_ptr != NULL)
+ *end_ptr = (png_byte)((end_byte & end_mask) | (*end_ptr & ~end_mask));
+}
+
+#ifdef PNG_READ_INTERLACING_SUPPORTED
+void /* PRIVATE */
+png_do_read_interlace(png_row_infop row_info, png_bytep row, int pass,
+ png_uint_32 transformations /* Because these may affect the byte layout */)
+{
+ /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
+ /* Offset to next interlace block */
+ static PNG_CONST int png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
+
+ png_debug(1, "in png_do_read_interlace");
+ if (row != NULL && row_info != NULL)
+ {
+ png_uint_32 final_width;
+
+ final_width = row_info->width * png_pass_inc[pass];
+
+ switch (row_info->pixel_depth)
+ {
+ case 1:
+ {
+ png_bytep sp = row + (png_size_t)((row_info->width - 1) >> 3);
+ png_bytep dp = row + (png_size_t)((final_width - 1) >> 3);
+ int sshift, dshift;
+ int s_start, s_end, s_inc;
+ int jstop = png_pass_inc[pass];
+ png_byte v;
+ png_uint_32 i;
+ int j;
+
+#ifdef PNG_READ_PACKSWAP_SUPPORTED
+ if ((transformations & PNG_PACKSWAP) != 0)
+ {
+ sshift = (int)((row_info->width + 7) & 0x07);
+ dshift = (int)((final_width + 7) & 0x07);
+ s_start = 7;
+ s_end = 0;
+ s_inc = -1;
+ }
+
+ else
+#endif
+ {
+ sshift = 7 - (int)((row_info->width + 7) & 0x07);
+ dshift = 7 - (int)((final_width + 7) & 0x07);
+ s_start = 0;
+ s_end = 7;
+ s_inc = 1;
+ }
+
+ for (i = 0; i < row_info->width; i++)
+ {
+ v = (png_byte)((*sp >> sshift) & 0x01);
+ for (j = 0; j < jstop; j++)
+ {
+ unsigned int tmp = *dp & (0x7f7f >> (7 - dshift));
+ tmp |= v << dshift;
+ *dp = (png_byte)(tmp & 0xff);
+
+ if (dshift == s_end)
+ {
+ dshift = s_start;
+ dp--;
+ }
+
+ else
+ dshift += s_inc;
+ }
+
+ if (sshift == s_end)
+ {
+ sshift = s_start;
+ sp--;
+ }
+
+ else
+ sshift += s_inc;
+ }
+ break;
+ }
+
+ case 2:
+ {
+ png_bytep sp = row + (png_uint_32)((row_info->width - 1) >> 2);
+ png_bytep dp = row + (png_uint_32)((final_width - 1) >> 2);
+ int sshift, dshift;
+ int s_start, s_end, s_inc;
+ int jstop = png_pass_inc[pass];
+ png_uint_32 i;
+
+#ifdef PNG_READ_PACKSWAP_SUPPORTED
+ if ((transformations & PNG_PACKSWAP) != 0)
+ {
+ sshift = (int)(((row_info->width + 3) & 0x03) << 1);
+ dshift = (int)(((final_width + 3) & 0x03) << 1);
+ s_start = 6;
+ s_end = 0;
+ s_inc = -2;
+ }
+
+ else
+#endif
+ {
+ sshift = (int)((3 - ((row_info->width + 3) & 0x03)) << 1);
+ dshift = (int)((3 - ((final_width + 3) & 0x03)) << 1);
+ s_start = 0;
+ s_end = 6;
+ s_inc = 2;
+ }
+
+ for (i = 0; i < row_info->width; i++)
+ {
+ png_byte v;
+ int j;
+
+ v = (png_byte)((*sp >> sshift) & 0x03);
+ for (j = 0; j < jstop; j++)
+ {
+ unsigned int tmp = *dp & (0x3f3f >> (6 - dshift));
+ tmp |= v << dshift;
+ *dp = (png_byte)(tmp & 0xff);
+
+ if (dshift == s_end)
+ {
+ dshift = s_start;
+ dp--;
+ }
+
+ else
+ dshift += s_inc;
+ }
+
+ if (sshift == s_end)
+ {
+ sshift = s_start;
+ sp--;
+ }
+
+ else
+ sshift += s_inc;
+ }
+ break;
+ }
+
+ case 4:
+ {
+ png_bytep sp = row + (png_size_t)((row_info->width - 1) >> 1);
+ png_bytep dp = row + (png_size_t)((final_width - 1) >> 1);
+ int sshift, dshift;
+ int s_start, s_end, s_inc;
+ png_uint_32 i;
+ int jstop = png_pass_inc[pass];
+
+#ifdef PNG_READ_PACKSWAP_SUPPORTED
+ if ((transformations & PNG_PACKSWAP) != 0)
+ {
+ sshift = (int)(((row_info->width + 1) & 0x01) << 2);
+ dshift = (int)(((final_width + 1) & 0x01) << 2);
+ s_start = 4;
+ s_end = 0;
+ s_inc = -4;
+ }
+
+ else
+#endif
+ {
+ sshift = (int)((1 - ((row_info->width + 1) & 0x01)) << 2);
+ dshift = (int)((1 - ((final_width + 1) & 0x01)) << 2);
+ s_start = 0;
+ s_end = 4;
+ s_inc = 4;
+ }
+
+ for (i = 0; i < row_info->width; i++)
+ {
+ png_byte v = (png_byte)((*sp >> sshift) & 0x0f);
+ int j;
+
+ for (j = 0; j < jstop; j++)
+ {
+ unsigned int tmp = *dp & (0xf0f >> (4 - dshift));
+ tmp |= v << dshift;
+ *dp = (png_byte)(tmp & 0xff);
+
+ if (dshift == s_end)
+ {
+ dshift = s_start;
+ dp--;
+ }
+
+ else
+ dshift += s_inc;
+ }
+
+ if (sshift == s_end)
+ {
+ sshift = s_start;
+ sp--;
+ }
+
+ else
+ sshift += s_inc;
+ }
+ break;
+ }
+
+ default:
+ {
+ png_size_t pixel_bytes = (row_info->pixel_depth >> 3);
+
+ png_bytep sp = row + (png_size_t)(row_info->width - 1)
+ * pixel_bytes;
+
+ png_bytep dp = row + (png_size_t)(final_width - 1) * pixel_bytes;
+
+ int jstop = png_pass_inc[pass];
+ png_uint_32 i;
+
+ for (i = 0; i < row_info->width; i++)
+ {
+ png_byte v[8]; /* SAFE; pixel_depth does not exceed 64 */
+ int j;
+
+ memcpy(v, sp, pixel_bytes);
+
+ for (j = 0; j < jstop; j++)
+ {
+ memcpy(dp, v, pixel_bytes);
+ dp -= pixel_bytes;
+ }
+
+ sp -= pixel_bytes;
+ }
+ break;
+ }
+ }
+
+ row_info->width = final_width;
+ row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, final_width);
+ }
+#ifndef PNG_READ_PACKSWAP_SUPPORTED
+ PNG_UNUSED(transformations) /* Silence compiler warning */
+#endif
+}
+#endif /* READ_INTERLACING */
+
+static void
+png_read_filter_row_sub(png_row_infop row_info, png_bytep row,
+ png_const_bytep prev_row)
+{
+ png_size_t i;
+ png_size_t istop = row_info->rowbytes;
+ unsigned int bpp = (row_info->pixel_depth + 7) >> 3;
+ png_bytep rp = row + bpp;
+
+ PNG_UNUSED(prev_row)
+
+ for (i = bpp; i < istop; i++)
+ {
+ *rp = (png_byte)(((int)(*rp) + (int)(*(rp-bpp))) & 0xff);
+ rp++;
+ }
+}
+
+static void
+png_read_filter_row_up(png_row_infop row_info, png_bytep row,
+ png_const_bytep prev_row)
+{
+ png_size_t i;
+ png_size_t istop = row_info->rowbytes;
+ png_bytep rp = row;
+ png_const_bytep pp = prev_row;
+
+ for (i = 0; i < istop; i++)
+ {
+ *rp = (png_byte)(((int)(*rp) + (int)(*pp++)) & 0xff);
+ rp++;
+ }
+}
+
+static void
+png_read_filter_row_avg(png_row_infop row_info, png_bytep row,
+ png_const_bytep prev_row)
+{
+ png_size_t i;
+ png_bytep rp = row;
+ png_const_bytep pp = prev_row;
+ unsigned int bpp = (row_info->pixel_depth + 7) >> 3;
+ png_size_t istop = row_info->rowbytes - bpp;
+
+ for (i = 0; i < bpp; i++)
+ {
+ *rp = (png_byte)(((int)(*rp) +
+ ((int)(*pp++) / 2 )) & 0xff);
+
+ rp++;
+ }
+
+ for (i = 0; i < istop; i++)
+ {
+ *rp = (png_byte)(((int)(*rp) +
+ (int)(*pp++ + *(rp-bpp)) / 2 ) & 0xff);
+
+ rp++;
+ }
+}
+
+static void
+png_read_filter_row_paeth_1byte_pixel(png_row_infop row_info, png_bytep row,
+ png_const_bytep prev_row)
+{
+ png_bytep rp_end = row + row_info->rowbytes;
+ int a, c;
+
+ /* First pixel/byte */
+ c = *prev_row++;
+ a = *row + c;
+ *row++ = (png_byte)a;
+
+ /* Remainder */
+ while (row < rp_end)
+ {
+ int b, pa, pb, pc, p;
+
+ a &= 0xff; /* From previous iteration or start */
+ b = *prev_row++;
+
+ p = b - c;
+ pc = a - c;
+
+# ifdef PNG_USE_ABS
+ pa = abs(p);
+ pb = abs(pc);
+ pc = abs(p + pc);
+# else
+ pa = p < 0 ? -p : p;
+ pb = pc < 0 ? -pc : pc;
+ pc = (p + pc) < 0 ? -(p + pc) : p + pc;
+# endif
+
+ /* Find the best predictor, the least of pa, pb, pc favoring the earlier
+ * ones in the case of a tie.
+ */
+ if (pb < pa) pa = pb, a = b;
+ if (pc < pa) a = c;
+
+ /* Calculate the current pixel in a, and move the previous row pixel to c
+ * for the next time round the loop
+ */
+ c = b;
+ a += *row;
+ *row++ = (png_byte)a;
+ }
+}
+
+static void
+png_read_filter_row_paeth_multibyte_pixel(png_row_infop row_info, png_bytep row,
+ png_const_bytep prev_row)
+{
+ int bpp = (row_info->pixel_depth + 7) >> 3;
+ png_bytep rp_end = row + bpp;
+
+ /* Process the first pixel in the row completely (this is the same as 'up'
+ * because there is only one candidate predictor for the first row).
+ */
+ while (row < rp_end)
+ {
+ int a = *row + *prev_row++;
+ *row++ = (png_byte)a;
+ }
+
+ /* Remainder */
+ rp_end += row_info->rowbytes - bpp;
+
+ while (row < rp_end)
+ {
+ int a, b, c, pa, pb, pc, p;
+
+ c = *(prev_row - bpp);
+ a = *(row - bpp);
+ b = *prev_row++;
+
+ p = b - c;
+ pc = a - c;
+
+# ifdef PNG_USE_ABS
+ pa = abs(p);
+ pb = abs(pc);
+ pc = abs(p + pc);
+# else
+ pa = p < 0 ? -p : p;
+ pb = pc < 0 ? -pc : pc;
+ pc = (p + pc) < 0 ? -(p + pc) : p + pc;
+# endif
+
+ if (pb < pa) pa = pb, a = b;
+ if (pc < pa) a = c;
+
+ a += *row;
+ *row++ = (png_byte)a;
+ }
+}
+
+static void
+png_init_filter_functions(png_structrp pp)
+ /* This function is called once for every PNG image (except for PNG images
+ * that only use PNG_FILTER_VALUE_NONE for all rows) to set the
+ * implementations required to reverse the filtering of PNG rows. Reversing
+ * the filter is the first transformation performed on the row data. It is
+ * performed in place, therefore an implementation can be selected based on
+ * the image pixel format. If the implementation depends on image width then
+ * take care to ensure that it works correctly if the image is interlaced -
+ * interlacing causes the actual row width to vary.
+ */
+{
+ unsigned int bpp = (pp->pixel_depth + 7) >> 3;
+
+ pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub;
+ pp->read_filter[PNG_FILTER_VALUE_UP-1] = png_read_filter_row_up;
+ pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg;
+ if (bpp == 1)
+ pp->read_filter[PNG_FILTER_VALUE_PAETH-1] =
+ png_read_filter_row_paeth_1byte_pixel;
+ else
+ pp->read_filter[PNG_FILTER_VALUE_PAETH-1] =
+ png_read_filter_row_paeth_multibyte_pixel;
+
+#ifdef PNG_FILTER_OPTIMIZATIONS
+ /* To use this define PNG_FILTER_OPTIMIZATIONS as the name of a function to
+ * call to install hardware optimizations for the above functions; simply
+ * replace whatever elements of the pp->read_filter[] array with a hardware
+ * specific (or, for that matter, generic) optimization.
+ *
+ * To see an example of this examine what configure.ac does when
+ * --enable-arm-neon is specified on the command line.
+ */
+ PNG_FILTER_OPTIMIZATIONS(pp, bpp);
+#endif
+}
+
+void /* PRIVATE */
+png_read_filter_row(png_structrp pp, png_row_infop row_info, png_bytep row,
+ png_const_bytep prev_row, int filter)
+{
+ /* OPTIMIZATION: DO NOT MODIFY THIS FUNCTION, instead #define
+ * PNG_FILTER_OPTIMIZATIONS to a function that overrides the generic
+ * implementations. See png_init_filter_functions above.
+ */
+ if (filter > PNG_FILTER_VALUE_NONE && filter < PNG_FILTER_VALUE_LAST)
+ {
+ if (pp->read_filter[0] == NULL)
+ png_init_filter_functions(pp);
+
+ pp->read_filter[filter-1](row_info, row, prev_row);
+ }
+}
+
+#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
+void /* PRIVATE */
+png_read_IDAT_data(png_structrp png_ptr, png_bytep output,
+ png_alloc_size_t avail_out)
+{
+ /* Loop reading IDATs and decompressing the result into output[avail_out] */
+ png_ptr->zstream.next_out = output;
+ png_ptr->zstream.avail_out = 0; /* safety: set below */
+
+ if (output == NULL)
+ avail_out = 0;
+
+ do
+ {
+ int ret;
+ png_byte tmpbuf[PNG_INFLATE_BUF_SIZE];
+
+ if (png_ptr->zstream.avail_in == 0)
+ {
+ uInt avail_in;
+ png_bytep buffer;
+
+ while (png_ptr->idat_size == 0)
+ {
+ png_crc_finish(png_ptr, 0);
+
+ png_ptr->idat_size = png_read_chunk_header(png_ptr);
+ /* This is an error even in the 'check' case because the code just
+ * consumed a non-IDAT header.
+ */
+ if (png_ptr->chunk_name != png_IDAT)
+ png_error(png_ptr, "Not enough image data");
+ }
+
+ avail_in = png_ptr->IDAT_read_size;
+
+ if (avail_in > png_ptr->idat_size)
+ avail_in = (uInt)png_ptr->idat_size;
+
+ /* A PNG with a gradually increasing IDAT size will defeat this attempt
+ * to minimize memory usage by causing lots of re-allocs, but
+ * realistically doing IDAT_read_size re-allocs is not likely to be a
+ * big problem.
+ */
+ buffer = png_read_buffer(png_ptr, avail_in, 0/*error*/);
+
+ png_crc_read(png_ptr, buffer, avail_in);
+ png_ptr->idat_size -= avail_in;
+
+ png_ptr->zstream.next_in = buffer;
+ png_ptr->zstream.avail_in = avail_in;
+ }
+
+ /* And set up the output side. */
+ if (output != NULL) /* standard read */
+ {
+ uInt out = ZLIB_IO_MAX;
+
+ if (out > avail_out)
+ out = (uInt)avail_out;
+
+ avail_out -= out;
+ png_ptr->zstream.avail_out = out;
+ }
+
+ else /* after last row, checking for end */
+ {
+ png_ptr->zstream.next_out = tmpbuf;
+ png_ptr->zstream.avail_out = (sizeof tmpbuf);
+ }
+
+ /* Use NO_FLUSH; this gives zlib the maximum opportunity to optimize the
+ * process. If the LZ stream is truncated the sequential reader will
+ * terminally damage the stream, above, by reading the chunk header of the
+ * following chunk (it then exits with png_error).
+ *
+ * TODO: deal more elegantly with truncated IDAT lists.
+ */
+ ret = inflate(&png_ptr->zstream, Z_NO_FLUSH);
+
+ /* Take the unconsumed output back. */
+ if (output != NULL)
+ avail_out += png_ptr->zstream.avail_out;
+
+ else /* avail_out counts the extra bytes */
+ avail_out += (sizeof tmpbuf) - png_ptr->zstream.avail_out;
+
+ png_ptr->zstream.avail_out = 0;
+
+ if (ret == Z_STREAM_END)
+ {
+ /* Do this for safety; we won't read any more into this row. */
+ png_ptr->zstream.next_out = NULL;
+
+ png_ptr->mode |= PNG_AFTER_IDAT;
+ png_ptr->flags |= PNG_FLAG_ZSTREAM_ENDED;
+
+ if (png_ptr->zstream.avail_in > 0 || png_ptr->idat_size > 0)
+ png_chunk_benign_error(png_ptr, "Extra compressed data");
+ break;
+ }
+
+ if (ret != Z_OK)
+ {
+ png_zstream_error(png_ptr, ret);
+
+ if (output != NULL)
+ png_chunk_error(png_ptr, png_ptr->zstream.msg);
+
+ else /* checking */
+ {
+ png_chunk_benign_error(png_ptr, png_ptr->zstream.msg);
+ return;
+ }
+ }
+ } while (avail_out > 0);
+
+ if (avail_out > 0)
+ {
+ /* The stream ended before the image; this is the same as too few IDATs so
+ * should be handled the same way.
+ */
+ if (output != NULL)
+ png_error(png_ptr, "Not enough image data");
+
+ else /* the deflate stream contained extra data */
+ png_chunk_benign_error(png_ptr, "Too much image data");
+ }
+}
+
+void /* PRIVATE */
+png_read_finish_IDAT(png_structrp png_ptr)
+{
+ /* We don't need any more data and the stream should have ended, however the
+ * LZ end code may actually not have been processed. In this case we must
+ * read it otherwise stray unread IDAT data or, more likely, an IDAT chunk
+ * may still remain to be consumed.
+ */
+ if ((png_ptr->flags & PNG_FLAG_ZSTREAM_ENDED) == 0)
+ {
+ /* The NULL causes png_read_IDAT_data to swallow any remaining bytes in
+ * the compressed stream, but the stream may be damaged too, so even after
+ * this call we may need to terminate the zstream ownership.
+ */
+ png_read_IDAT_data(png_ptr, NULL, 0);
+ png_ptr->zstream.next_out = NULL; /* safety */
+
+ /* Now clear everything out for safety; the following may not have been
+ * done.
+ */
+ if ((png_ptr->flags & PNG_FLAG_ZSTREAM_ENDED) == 0)
+ {
+ png_ptr->mode |= PNG_AFTER_IDAT;
+ png_ptr->flags |= PNG_FLAG_ZSTREAM_ENDED;
+ }
+ }
+
+ /* If the zstream has not been released do it now *and* terminate the reading
+ * of the final IDAT chunk.
+ */
+ if (png_ptr->zowner == png_IDAT)
+ {
+ /* Always do this; the pointers otherwise point into the read buffer. */
+ png_ptr->zstream.next_in = NULL;
+ png_ptr->zstream.avail_in = 0;
+
+ /* Now we no longer own the zstream. */
+ png_ptr->zowner = 0;
+
+ /* The slightly weird semantics of the sequential IDAT reading is that we
+ * are always in or at the end of an IDAT chunk, so we always need to do a
+ * crc_finish here. If idat_size is non-zero we also need to read the
+ * spurious bytes at the end of the chunk now.
+ */
+ (void)png_crc_finish(png_ptr, png_ptr->idat_size);
+ }
+}
+
+void /* PRIVATE */
+png_read_finish_row(png_structrp png_ptr)
+{
+ /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
+
+ /* Start of interlace block */
+ static PNG_CONST png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
+
+ /* Offset to next interlace block */
+ static PNG_CONST png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
+
+ /* Start of interlace block in the y direction */
+ static PNG_CONST png_byte png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1};
+
+ /* Offset to next interlace block in the y direction */
+ static PNG_CONST png_byte png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};
+
+ png_debug(1, "in png_read_finish_row");
+ png_ptr->row_number++;
+ if (png_ptr->row_number < png_ptr->num_rows)
+ return;
+
+ if (png_ptr->interlaced != 0)
+ {
+ png_ptr->row_number = 0;
+
+ /* TO DO: don't do this if prev_row isn't needed (requires
+ * read-ahead of the next row's filter byte.
+ */
+ memset(png_ptr->prev_row, 0, png_ptr->rowbytes + 1);
+
+ do
+ {
+ png_ptr->pass++;
+
+ if (png_ptr->pass >= 7)
+ break;
+
+ png_ptr->iwidth = (png_ptr->width +
+ png_pass_inc[png_ptr->pass] - 1 -
+ png_pass_start[png_ptr->pass]) /
+ png_pass_inc[png_ptr->pass];
+
+ if ((png_ptr->transformations & PNG_INTERLACE) == 0)
+ {
+ png_ptr->num_rows = (png_ptr->height +
+ png_pass_yinc[png_ptr->pass] - 1 -
+ png_pass_ystart[png_ptr->pass]) /
+ png_pass_yinc[png_ptr->pass];
+ }
+
+ else /* if (png_ptr->transformations & PNG_INTERLACE) */
+ break; /* libpng deinterlacing sees every row */
+
+ } while (png_ptr->num_rows == 0 || png_ptr->iwidth == 0);
+
+ if (png_ptr->pass < 7)
+ return;
+ }
+
+ /* Here after at the end of the last row of the last pass. */
+ png_read_finish_IDAT(png_ptr);
+}
+#endif /* SEQUENTIAL_READ */
+
+void /* PRIVATE */
+png_read_start_row(png_structrp png_ptr)
+{
+ /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
+
+ /* Start of interlace block */
+ static PNG_CONST png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
+
+ /* Offset to next interlace block */
+ static PNG_CONST png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
+
+ /* Start of interlace block in the y direction */
+ static PNG_CONST png_byte png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1};
+
+ /* Offset to next interlace block in the y direction */
+ static PNG_CONST png_byte png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};
+
+ int max_pixel_depth;
+ png_size_t row_bytes;
+
+ png_debug(1, "in png_read_start_row");
+
+#ifdef PNG_READ_TRANSFORMS_SUPPORTED
+ png_init_read_transformations(png_ptr);
+#endif
+ if (png_ptr->interlaced != 0)
+ {
+ if ((png_ptr->transformations & PNG_INTERLACE) == 0)
+ png_ptr->num_rows = (png_ptr->height + png_pass_yinc[0] - 1 -
+ png_pass_ystart[0]) / png_pass_yinc[0];
+
+ else
+ png_ptr->num_rows = png_ptr->height;
+
+ png_ptr->iwidth = (png_ptr->width +
+ png_pass_inc[png_ptr->pass] - 1 -
+ png_pass_start[png_ptr->pass]) /
+ png_pass_inc[png_ptr->pass];
+ }
+
+ else
+ {
+ png_ptr->num_rows = png_ptr->height;
+ png_ptr->iwidth = png_ptr->width;
+ }
+
+ max_pixel_depth = png_ptr->pixel_depth;
+
+ /* WARNING: * png_read_transform_info (pngrtran.c) performs a simpler set of
+ * calculations to calculate the final pixel depth, then
+ * png_do_read_transforms actually does the transforms. This means that the
+ * code which effectively calculates this value is actually repeated in three
+ * separate places. They must all match. Innocent changes to the order of
+ * transformations can and will break libpng in a way that causes memory
+ * overwrites.
+ *
+ * TODO: fix this.
+ */
+#ifdef PNG_READ_PACK_SUPPORTED
+ if ((png_ptr->transformations & PNG_PACK) != 0 && png_ptr->bit_depth < 8)
+ max_pixel_depth = 8;
+#endif
+
+#ifdef PNG_READ_EXPAND_SUPPORTED
+ if ((png_ptr->transformations & PNG_EXPAND) != 0)
+ {
+ if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
+ {
+ if (png_ptr->num_trans != 0)
+ max_pixel_depth = 32;
+
+ else
+ max_pixel_depth = 24;
+ }
+
+ else if (png_ptr->color_type == PNG_COLOR_TYPE_GRAY)
+ {
+ if (max_pixel_depth < 8)
+ max_pixel_depth = 8;
+
+ if (png_ptr->num_trans != 0)
+ max_pixel_depth *= 2;
+ }
+
+ else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB)
+ {
+ if (png_ptr->num_trans != 0)
+ {
+ max_pixel_depth *= 4;
+ max_pixel_depth /= 3;
+ }
+ }
+ }
+#endif
+
+#ifdef PNG_READ_EXPAND_16_SUPPORTED
+ if ((png_ptr->transformations & PNG_EXPAND_16) != 0)
+ {
+# ifdef PNG_READ_EXPAND_SUPPORTED
+ /* In fact it is an error if it isn't supported, but checking is
+ * the safe way.
+ */
+ if ((png_ptr->transformations & PNG_EXPAND) != 0)
+ {
+ if (png_ptr->bit_depth < 16)
+ max_pixel_depth *= 2;
+ }
+ else
+# endif
+ png_ptr->transformations &= ~PNG_EXPAND_16;
+ }
+#endif
+
+#ifdef PNG_READ_FILLER_SUPPORTED
+ if ((png_ptr->transformations & (PNG_FILLER)) != 0)
+ {
+ if (png_ptr->color_type == PNG_COLOR_TYPE_GRAY)
+ {
+ if (max_pixel_depth <= 8)
+ max_pixel_depth = 16;
+
+ else
+ max_pixel_depth = 32;
+ }
+
+ else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB ||
+ png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
+ {
+ if (max_pixel_depth <= 32)
+ max_pixel_depth = 32;
+
+ else
+ max_pixel_depth = 64;
+ }
+ }
+#endif
+
+#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
+ if ((png_ptr->transformations & PNG_GRAY_TO_RGB) != 0)
+ {
+ if (
+#ifdef PNG_READ_EXPAND_SUPPORTED
+ (png_ptr->num_trans != 0 &&
+ (png_ptr->transformations & PNG_EXPAND) != 0) ||
+#endif
+#ifdef PNG_READ_FILLER_SUPPORTED
+ (png_ptr->transformations & (PNG_FILLER)) != 0 ||
+#endif
+ png_ptr->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
+ {
+ if (max_pixel_depth <= 16)
+ max_pixel_depth = 32;
+
+ else
+ max_pixel_depth = 64;
+ }
+
+ else
+ {
+ if (max_pixel_depth <= 8)
+ {
+ if (png_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+ max_pixel_depth = 32;
+
+ else
+ max_pixel_depth = 24;
+ }
+
+ else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+ max_pixel_depth = 64;
+
+ else
+ max_pixel_depth = 48;
+ }
+ }
+#endif
+
+#if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) && \
+defined(PNG_USER_TRANSFORM_PTR_SUPPORTED)
+ if ((png_ptr->transformations & PNG_USER_TRANSFORM) != 0)
+ {
+ int user_pixel_depth = png_ptr->user_transform_depth *
+ png_ptr->user_transform_channels;
+
+ if (user_pixel_depth > max_pixel_depth)
+ max_pixel_depth = user_pixel_depth;
+ }
+#endif
+
+ /* This value is stored in png_struct and double checked in the row read
+ * code.
+ */
+ png_ptr->maximum_pixel_depth = (png_byte)max_pixel_depth;
+ png_ptr->transformed_pixel_depth = 0; /* calculated on demand */
+
+ /* Align the width on the next larger 8 pixels. Mainly used
+ * for interlacing
+ */
+ row_bytes = ((png_ptr->width + 7) & ~((png_uint_32)7));
+ /* Calculate the maximum bytes needed, adding a byte and a pixel
+ * for safety's sake
+ */
+ row_bytes = PNG_ROWBYTES(max_pixel_depth, row_bytes) +
+ 1 + ((max_pixel_depth + 7) >> 3);
+
+#ifdef PNG_MAX_MALLOC_64K
+ if (row_bytes > (png_uint_32)65536L)
+ png_error(png_ptr, "This image requires a row greater than 64KB");
+#endif
+
+ if (row_bytes + 48 > png_ptr->old_big_row_buf_size)
+ {
+ png_free(png_ptr, png_ptr->big_row_buf);
+ png_free(png_ptr, png_ptr->big_prev_row);
+
+ if (png_ptr->interlaced != 0)
+ png_ptr->big_row_buf = (png_bytep)png_calloc(png_ptr,
+ row_bytes + 48);
+
+ else
+ png_ptr->big_row_buf = (png_bytep)png_malloc(png_ptr, row_bytes + 48);
+
+ png_ptr->big_prev_row = (png_bytep)png_malloc(png_ptr, row_bytes + 48);
+
+#ifdef PNG_ALIGNED_MEMORY_SUPPORTED
+ /* Use 16-byte aligned memory for row_buf with at least 16 bytes
+ * of padding before and after row_buf; treat prev_row similarly.
+ * NOTE: the alignment is to the start of the pixels, one beyond the start
+ * of the buffer, because of the filter byte. Prior to libpng 1.5.6 this
+ * was incorrect; the filter byte was aligned, which had the exact
+ * opposite effect of that intended.
+ */
+ {
+ png_bytep temp = png_ptr->big_row_buf + 32;
+ int extra = (int)((temp - (png_bytep)0) & 0x0f);
+ png_ptr->row_buf = temp - extra - 1/*filter byte*/;
+
+ temp = png_ptr->big_prev_row + 32;
+ extra = (int)((temp - (png_bytep)0) & 0x0f);
+ png_ptr->prev_row = temp - extra - 1/*filter byte*/;
+ }
+
+#else
+ /* Use 31 bytes of padding before and 17 bytes after row_buf. */
+ png_ptr->row_buf = png_ptr->big_row_buf + 31;
+ png_ptr->prev_row = png_ptr->big_prev_row + 31;
+#endif
+ png_ptr->old_big_row_buf_size = row_bytes + 48;
+ }
+
+#ifdef PNG_MAX_MALLOC_64K
+ if (png_ptr->rowbytes > 65535)
+ png_error(png_ptr, "This image requires a row greater than 64KB");
+
+#endif
+ if (png_ptr->rowbytes > (PNG_SIZE_MAX - 1))
+ png_error(png_ptr, "Row has too many bytes to allocate in memory");
+
+ memset(png_ptr->prev_row, 0, png_ptr->rowbytes + 1);
+
+ png_debug1(3, "width = %u,", png_ptr->width);
+ png_debug1(3, "height = %u,", png_ptr->height);
+ png_debug1(3, "iwidth = %u,", png_ptr->iwidth);
+ png_debug1(3, "num_rows = %u,", png_ptr->num_rows);
+ png_debug1(3, "rowbytes = %lu,", (unsigned long)png_ptr->rowbytes);
+ png_debug1(3, "irowbytes = %lu",
+ (unsigned long)PNG_ROWBYTES(png_ptr->pixel_depth, png_ptr->iwidth) + 1);
+
+ /* The sequential reader needs a buffer for IDAT, but the progressive reader
+ * does not, so free the read buffer now regardless; the sequential reader
+ * reallocates it on demand.
+ */
+ if (png_ptr->read_buffer != 0)
+ {
+ png_bytep buffer = png_ptr->read_buffer;
+
+ png_ptr->read_buffer_size = 0;
+ png_ptr->read_buffer = NULL;
+ png_free(png_ptr, buffer);
+ }
+
+ /* Finally claim the zstream for the inflate of the IDAT data, use the bits
+ * value from the stream (note that this will result in a fatal error if the
+ * IDAT stream has a bogus deflate header window_bits value, but this should
+ * not be happening any longer!)
+ */
+ if (png_inflate_claim(png_ptr, png_IDAT) != Z_OK)
+ png_error(png_ptr, png_ptr->zstream.msg);
+
+ png_ptr->flags |= PNG_FLAG_ROW_INIT;
+}
+#endif /* READ */
--- /dev/null
+
+/* pngset.c - storage of image information into info struct
+ *
+ * Last changed in libpng 1.6.17 [March 26, 2015]
+ * Copyright (c) 1998-2015 Glenn Randers-Pehrson
+ * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
+ * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ *
+ * The functions here are used during reads to store data from the file
+ * into the info struct, and during writes to store application data
+ * into the info struct for writing into the file. This abstracts the
+ * info struct and allows us to change the structure in the future.
+ */
+
+#include "pngpriv.h"
+
+#if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
+
+#ifdef PNG_bKGD_SUPPORTED
+void PNGAPI
+png_set_bKGD(png_const_structrp png_ptr, png_inforp info_ptr,
+ png_const_color_16p background)
+{
+ png_debug1(1, "in %s storage function", "bKGD");
+
+ if (png_ptr == NULL || info_ptr == NULL || background == NULL)
+ return;
+
+ info_ptr->background = *background;
+ info_ptr->valid |= PNG_INFO_bKGD;
+}
+#endif
+
+#ifdef PNG_cHRM_SUPPORTED
+void PNGFAPI
+png_set_cHRM_fixed(png_const_structrp png_ptr, png_inforp info_ptr,
+ png_fixed_point white_x, png_fixed_point white_y, png_fixed_point red_x,
+ png_fixed_point red_y, png_fixed_point green_x, png_fixed_point green_y,
+ png_fixed_point blue_x, png_fixed_point blue_y)
+{
+ png_xy xy;
+
+ png_debug1(1, "in %s storage function", "cHRM fixed");
+
+ if (png_ptr == NULL || info_ptr == NULL)
+ return;
+
+ xy.redx = red_x;
+ xy.redy = red_y;
+ xy.greenx = green_x;
+ xy.greeny = green_y;
+ xy.bluex = blue_x;
+ xy.bluey = blue_y;
+ xy.whitex = white_x;
+ xy.whitey = white_y;
+
+ if (png_colorspace_set_chromaticities(png_ptr, &info_ptr->colorspace, &xy,
+ 2/* override with app values*/) != 0)
+ info_ptr->colorspace.flags |= PNG_COLORSPACE_FROM_cHRM;
+
+ png_colorspace_sync_info(png_ptr, info_ptr);
+}
+
+void PNGFAPI
+png_set_cHRM_XYZ_fixed(png_const_structrp png_ptr, png_inforp info_ptr,
+ png_fixed_point int_red_X, png_fixed_point int_red_Y,
+ png_fixed_point int_red_Z, png_fixed_point int_green_X,
+ png_fixed_point int_green_Y, png_fixed_point int_green_Z,
+ png_fixed_point int_blue_X, png_fixed_point int_blue_Y,
+ png_fixed_point int_blue_Z)
+{
+ png_XYZ XYZ;
+
+ png_debug1(1, "in %s storage function", "cHRM XYZ fixed");
+
+ if (png_ptr == NULL || info_ptr == NULL)
+ return;
+
+ XYZ.red_X = int_red_X;
+ XYZ.red_Y = int_red_Y;
+ XYZ.red_Z = int_red_Z;
+ XYZ.green_X = int_green_X;
+ XYZ.green_Y = int_green_Y;
+ XYZ.green_Z = int_green_Z;
+ XYZ.blue_X = int_blue_X;
+ XYZ.blue_Y = int_blue_Y;
+ XYZ.blue_Z = int_blue_Z;
+
+ if (png_colorspace_set_endpoints(png_ptr, &info_ptr->colorspace,
+ &XYZ, 2) != 0)
+ info_ptr->colorspace.flags |= PNG_COLORSPACE_FROM_cHRM;
+
+ png_colorspace_sync_info(png_ptr, info_ptr);
+}
+
+# ifdef PNG_FLOATING_POINT_SUPPORTED
+void PNGAPI
+png_set_cHRM(png_const_structrp png_ptr, png_inforp info_ptr,
+ double white_x, double white_y, double red_x, double red_y,
+ double green_x, double green_y, double blue_x, double blue_y)
+{
+ png_set_cHRM_fixed(png_ptr, info_ptr,
+ png_fixed(png_ptr, white_x, "cHRM White X"),
+ png_fixed(png_ptr, white_y, "cHRM White Y"),
+ png_fixed(png_ptr, red_x, "cHRM Red X"),
+ png_fixed(png_ptr, red_y, "cHRM Red Y"),
+ png_fixed(png_ptr, green_x, "cHRM Green X"),
+ png_fixed(png_ptr, green_y, "cHRM Green Y"),
+ png_fixed(png_ptr, blue_x, "cHRM Blue X"),
+ png_fixed(png_ptr, blue_y, "cHRM Blue Y"));
+}
+
+void PNGAPI
+png_set_cHRM_XYZ(png_const_structrp png_ptr, png_inforp info_ptr, double red_X,
+ double red_Y, double red_Z, double green_X, double green_Y, double green_Z,
+ double blue_X, double blue_Y, double blue_Z)
+{
+ png_set_cHRM_XYZ_fixed(png_ptr, info_ptr,
+ png_fixed(png_ptr, red_X, "cHRM Red X"),
+ png_fixed(png_ptr, red_Y, "cHRM Red Y"),
+ png_fixed(png_ptr, red_Z, "cHRM Red Z"),
+ png_fixed(png_ptr, green_X, "cHRM Red X"),
+ png_fixed(png_ptr, green_Y, "cHRM Red Y"),
+ png_fixed(png_ptr, green_Z, "cHRM Red Z"),
+ png_fixed(png_ptr, blue_X, "cHRM Red X"),
+ png_fixed(png_ptr, blue_Y, "cHRM Red Y"),
+ png_fixed(png_ptr, blue_Z, "cHRM Red Z"));
+}
+# endif /* FLOATING_POINT */
+
+#endif /* cHRM */
+
+#ifdef PNG_gAMA_SUPPORTED
+void PNGFAPI
+png_set_gAMA_fixed(png_const_structrp png_ptr, png_inforp info_ptr,
+ png_fixed_point file_gamma)
+{
+ png_debug1(1, "in %s storage function", "gAMA");
+
+ if (png_ptr == NULL || info_ptr == NULL)
+ return;
+
+ png_colorspace_set_gamma(png_ptr, &info_ptr->colorspace, file_gamma);
+ png_colorspace_sync_info(png_ptr, info_ptr);
+}
+
+# ifdef PNG_FLOATING_POINT_SUPPORTED
+void PNGAPI
+png_set_gAMA(png_const_structrp png_ptr, png_inforp info_ptr, double file_gamma)
+{
+ png_set_gAMA_fixed(png_ptr, info_ptr, png_fixed(png_ptr, file_gamma,
+ "png_set_gAMA"));
+}
+# endif
+#endif
+
+#ifdef PNG_hIST_SUPPORTED
+void PNGAPI
+png_set_hIST(png_const_structrp png_ptr, png_inforp info_ptr,
+ png_const_uint_16p hist)
+{
+ int i;
+
+ png_debug1(1, "in %s storage function", "hIST");
+
+ if (png_ptr == NULL || info_ptr == NULL)
+ return;
+
+ if (info_ptr->num_palette == 0 || info_ptr->num_palette
+ > PNG_MAX_PALETTE_LENGTH)
+ {
+ png_warning(png_ptr,
+ "Invalid palette size, hIST allocation skipped");
+
+ return;
+ }
+
+ png_free_data(png_ptr, info_ptr, PNG_FREE_HIST, 0);
+
+ /* Changed from info->num_palette to PNG_MAX_PALETTE_LENGTH in
+ * version 1.2.1
+ */
+ info_ptr->hist = png_voidcast(png_uint_16p, png_malloc_warn(png_ptr,
+ PNG_MAX_PALETTE_LENGTH * (sizeof (png_uint_16))));
+
+ if (info_ptr->hist == NULL)
+ {
+ png_warning(png_ptr, "Insufficient memory for hIST chunk data");
+
+ return;
+ }
+
+ info_ptr->free_me |= PNG_FREE_HIST;
+
+ for (i = 0; i < info_ptr->num_palette; i++)
+ info_ptr->hist[i] = hist[i];
+
+ info_ptr->valid |= PNG_INFO_hIST;
+}
+#endif
+
+void PNGAPI
+png_set_IHDR(png_const_structrp png_ptr, png_inforp info_ptr,
+ png_uint_32 width, png_uint_32 height, int bit_depth,
+ int color_type, int interlace_type, int compression_type,
+ int filter_type)
+{
+ png_debug1(1, "in %s storage function", "IHDR");
+
+ if (png_ptr == NULL || info_ptr == NULL)
+ return;
+
+ info_ptr->width = width;
+ info_ptr->height = height;
+ info_ptr->bit_depth = (png_byte)bit_depth;
+ info_ptr->color_type = (png_byte)color_type;
+ info_ptr->compression_type = (png_byte)compression_type;
+ info_ptr->filter_type = (png_byte)filter_type;
+ info_ptr->interlace_type = (png_byte)interlace_type;
+
+ png_check_IHDR (png_ptr, info_ptr->width, info_ptr->height,
+ info_ptr->bit_depth, info_ptr->color_type, info_ptr->interlace_type,
+ info_ptr->compression_type, info_ptr->filter_type);
+
+ if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
+ info_ptr->channels = 1;
+
+ else if ((info_ptr->color_type & PNG_COLOR_MASK_COLOR) != 0)
+ info_ptr->channels = 3;
+
+ else
+ info_ptr->channels = 1;
+
+ if ((info_ptr->color_type & PNG_COLOR_MASK_ALPHA) != 0)
+ info_ptr->channels++;
+
+ info_ptr->pixel_depth = (png_byte)(info_ptr->channels * info_ptr->bit_depth);
+
+ info_ptr->rowbytes = PNG_ROWBYTES(info_ptr->pixel_depth, width);
+}
+
+#ifdef PNG_oFFs_SUPPORTED
+void PNGAPI
+png_set_oFFs(png_const_structrp png_ptr, png_inforp info_ptr,
+ png_int_32 offset_x, png_int_32 offset_y, int unit_type)
+{
+ png_debug1(1, "in %s storage function", "oFFs");
+
+ if (png_ptr == NULL || info_ptr == NULL)
+ return;
+
+ info_ptr->x_offset = offset_x;
+ info_ptr->y_offset = offset_y;
+ info_ptr->offset_unit_type = (png_byte)unit_type;
+ info_ptr->valid |= PNG_INFO_oFFs;
+}
+#endif
+
+#ifdef PNG_pCAL_SUPPORTED
+void PNGAPI
+png_set_pCAL(png_const_structrp png_ptr, png_inforp info_ptr,
+ png_const_charp purpose, png_int_32 X0, png_int_32 X1, int type,
+ int nparams, png_const_charp units, png_charpp params)
+{
+ png_size_t length;
+ int i;
+
+ png_debug1(1, "in %s storage function", "pCAL");
+
+ if (png_ptr == NULL || info_ptr == NULL || purpose == NULL || units == NULL
+ || (nparams > 0 && params == NULL))
+ return;
+
+ length = strlen(purpose) + 1;
+ png_debug1(3, "allocating purpose for info (%lu bytes)",
+ (unsigned long)length);
+
+ /* TODO: validate format of calibration name and unit name */
+
+ /* Check that the type matches the specification. */
+ if (type < 0 || type > 3)
+ png_error(png_ptr, "Invalid pCAL equation type");
+
+ if (nparams < 0 || nparams > 255)
+ png_error(png_ptr, "Invalid pCAL parameter count");
+
+ /* Validate params[nparams] */
+ for (i=0; i<nparams; ++i)
+ {
+ if (params[i] == NULL ||
+ !png_check_fp_string(params[i], strlen(params[i])))
+ png_error(png_ptr, "Invalid format for pCAL parameter");
+ }
+
+ info_ptr->pcal_purpose = png_voidcast(png_charp,
+ png_malloc_warn(png_ptr, length));
+
+ if (info_ptr->pcal_purpose == NULL)
+ {
+ png_warning(png_ptr, "Insufficient memory for pCAL purpose");
+
+ return;
+ }
+
+ memcpy(info_ptr->pcal_purpose, purpose, length);
+
+ png_debug(3, "storing X0, X1, type, and nparams in info");
+ info_ptr->pcal_X0 = X0;
+ info_ptr->pcal_X1 = X1;
+ info_ptr->pcal_type = (png_byte)type;
+ info_ptr->pcal_nparams = (png_byte)nparams;
+
+ length = strlen(units) + 1;
+ png_debug1(3, "allocating units for info (%lu bytes)",
+ (unsigned long)length);
+
+ info_ptr->pcal_units = png_voidcast(png_charp,
+ png_malloc_warn(png_ptr, length));
+
+ if (info_ptr->pcal_units == NULL)
+ {
+ png_warning(png_ptr, "Insufficient memory for pCAL units");
+
+ return;
+ }
+
+ memcpy(info_ptr->pcal_units, units, length);
+
+ info_ptr->pcal_params = png_voidcast(png_charpp, png_malloc_warn(png_ptr,
+ (png_size_t)((nparams + 1) * (sizeof (png_charp)))));
+
+ if (info_ptr->pcal_params == NULL)
+ {
+ png_warning(png_ptr, "Insufficient memory for pCAL params");
+
+ return;
+ }
+
+ memset(info_ptr->pcal_params, 0, (nparams + 1) * (sizeof (png_charp)));
+
+ for (i = 0; i < nparams; i++)
+ {
+ length = strlen(params[i]) + 1;
+ png_debug2(3, "allocating parameter %d for info (%lu bytes)", i,
+ (unsigned long)length);
+
+ info_ptr->pcal_params[i] = (png_charp)png_malloc_warn(png_ptr, length);
+
+ if (info_ptr->pcal_params[i] == NULL)
+ {
+ png_warning(png_ptr, "Insufficient memory for pCAL parameter");
+
+ return;
+ }
+
+ memcpy(info_ptr->pcal_params[i], params[i], length);
+ }
+
+ info_ptr->valid |= PNG_INFO_pCAL;
+ info_ptr->free_me |= PNG_FREE_PCAL;
+}
+#endif
+
+#ifdef PNG_sCAL_SUPPORTED
+void PNGAPI
+png_set_sCAL_s(png_const_structrp png_ptr, png_inforp info_ptr,
+ int unit, png_const_charp swidth, png_const_charp sheight)
+{
+ png_size_t lengthw = 0, lengthh = 0;
+
+ png_debug1(1, "in %s storage function", "sCAL");
+
+ if (png_ptr == NULL || info_ptr == NULL)
+ return;
+
+ /* Double check the unit (should never get here with an invalid
+ * unit unless this is an API call.)
+ */
+ if (unit != 1 && unit != 2)
+ png_error(png_ptr, "Invalid sCAL unit");
+
+ if (swidth == NULL || (lengthw = strlen(swidth)) == 0 ||
+ swidth[0] == 45 /* '-' */ || !png_check_fp_string(swidth, lengthw))
+ png_error(png_ptr, "Invalid sCAL width");
+
+ if (sheight == NULL || (lengthh = strlen(sheight)) == 0 ||
+ sheight[0] == 45 /* '-' */ || !png_check_fp_string(sheight, lengthh))
+ png_error(png_ptr, "Invalid sCAL height");
+
+ info_ptr->scal_unit = (png_byte)unit;
+
+ ++lengthw;
+
+ png_debug1(3, "allocating unit for info (%u bytes)", (unsigned int)lengthw);
+
+ info_ptr->scal_s_width = png_voidcast(png_charp,
+ png_malloc_warn(png_ptr, lengthw));
+
+ if (info_ptr->scal_s_width == NULL)
+ {
+ png_warning(png_ptr, "Memory allocation failed while processing sCAL");
+
+ return;
+ }
+
+ memcpy(info_ptr->scal_s_width, swidth, lengthw);
+
+ ++lengthh;
+
+ png_debug1(3, "allocating unit for info (%u bytes)", (unsigned int)lengthh);
+
+ info_ptr->scal_s_height = png_voidcast(png_charp,
+ png_malloc_warn(png_ptr, lengthh));
+
+ if (info_ptr->scal_s_height == NULL)
+ {
+ png_free (png_ptr, info_ptr->scal_s_width);
+ info_ptr->scal_s_width = NULL;
+
+ png_warning(png_ptr, "Memory allocation failed while processing sCAL");
+
+ return;
+ }
+
+ memcpy(info_ptr->scal_s_height, sheight, lengthh);
+
+ info_ptr->valid |= PNG_INFO_sCAL;
+ info_ptr->free_me |= PNG_FREE_SCAL;
+}
+
+# ifdef PNG_FLOATING_POINT_SUPPORTED
+void PNGAPI
+png_set_sCAL(png_const_structrp png_ptr, png_inforp info_ptr, int unit,
+ double width, double height)
+{
+ png_debug1(1, "in %s storage function", "sCAL");
+
+ /* Check the arguments. */
+ if (width <= 0)
+ png_warning(png_ptr, "Invalid sCAL width ignored");
+
+ else if (height <= 0)
+ png_warning(png_ptr, "Invalid sCAL height ignored");
+
+ else
+ {
+ /* Convert 'width' and 'height' to ASCII. */
+ char swidth[PNG_sCAL_MAX_DIGITS+1];
+ char sheight[PNG_sCAL_MAX_DIGITS+1];
+
+ png_ascii_from_fp(png_ptr, swidth, (sizeof swidth), width,
+ PNG_sCAL_PRECISION);
+ png_ascii_from_fp(png_ptr, sheight, (sizeof sheight), height,
+ PNG_sCAL_PRECISION);
+
+ png_set_sCAL_s(png_ptr, info_ptr, unit, swidth, sheight);
+ }
+}
+# endif
+
+# ifdef PNG_FIXED_POINT_SUPPORTED
+void PNGAPI
+png_set_sCAL_fixed(png_const_structrp png_ptr, png_inforp info_ptr, int unit,
+ png_fixed_point width, png_fixed_point height)
+{
+ png_debug1(1, "in %s storage function", "sCAL");
+
+ /* Check the arguments. */
+ if (width <= 0)
+ png_warning(png_ptr, "Invalid sCAL width ignored");
+
+ else if (height <= 0)
+ png_warning(png_ptr, "Invalid sCAL height ignored");
+
+ else
+ {
+ /* Convert 'width' and 'height' to ASCII. */
+ char swidth[PNG_sCAL_MAX_DIGITS+1];
+ char sheight[PNG_sCAL_MAX_DIGITS+1];
+
+ png_ascii_from_fixed(png_ptr, swidth, (sizeof swidth), width);
+ png_ascii_from_fixed(png_ptr, sheight, (sizeof sheight), height);
+
+ png_set_sCAL_s(png_ptr, info_ptr, unit, swidth, sheight);
+ }
+}
+# endif
+#endif
+
+#ifdef PNG_pHYs_SUPPORTED
+void PNGAPI
+png_set_pHYs(png_const_structrp png_ptr, png_inforp info_ptr,
+ png_uint_32 res_x, png_uint_32 res_y, int unit_type)
+{
+ png_debug1(1, "in %s storage function", "pHYs");
+
+ if (png_ptr == NULL || info_ptr == NULL)
+ return;
+
+ info_ptr->x_pixels_per_unit = res_x;
+ info_ptr->y_pixels_per_unit = res_y;
+ info_ptr->phys_unit_type = (png_byte)unit_type;
+ info_ptr->valid |= PNG_INFO_pHYs;
+}
+#endif
+
+void PNGAPI
+png_set_PLTE(png_structrp png_ptr, png_inforp info_ptr,
+ png_const_colorp palette, int num_palette)
+{
+
+ png_debug1(1, "in %s storage function", "PLTE");
+
+ if (png_ptr == NULL || info_ptr == NULL)
+ return;
+
+ if (num_palette < 0 || num_palette > PNG_MAX_PALETTE_LENGTH)
+ {
+ if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
+ png_error(png_ptr, "Invalid palette length");
+
+ else
+ {
+ png_warning(png_ptr, "Invalid palette length");
+
+ return;
+ }
+ }
+
+ if ((num_palette > 0 && palette == NULL) ||
+ (num_palette == 0
+# ifdef PNG_MNG_FEATURES_SUPPORTED
+ && (png_ptr->mng_features_permitted & PNG_FLAG_MNG_EMPTY_PLTE) == 0
+# endif
+ ))
+ {
+ png_error(png_ptr, "Invalid palette");
+ }
+
+ /* It may not actually be necessary to set png_ptr->palette here;
+ * we do it for backward compatibility with the way the png_handle_tRNS
+ * function used to do the allocation.
+ *
+ * 1.6.0: the above statement appears to be incorrect; something has to set
+ * the palette inside png_struct on read.
+ */
+ png_free_data(png_ptr, info_ptr, PNG_FREE_PLTE, 0);
+
+ /* Changed in libpng-1.2.1 to allocate PNG_MAX_PALETTE_LENGTH instead
+ * of num_palette entries, in case of an invalid PNG file that has
+ * too-large sample values.
+ */
+ png_ptr->palette = png_voidcast(png_colorp, png_calloc(png_ptr,
+ PNG_MAX_PALETTE_LENGTH * (sizeof (png_color))));
+
+ if (num_palette > 0)
+ memcpy(png_ptr->palette, palette, num_palette * (sizeof (png_color)));
+ info_ptr->palette = png_ptr->palette;
+ info_ptr->num_palette = png_ptr->num_palette = (png_uint_16)num_palette;
+
+ info_ptr->free_me |= PNG_FREE_PLTE;
+
+ info_ptr->valid |= PNG_INFO_PLTE;
+}
+
+#ifdef PNG_sBIT_SUPPORTED
+void PNGAPI
+png_set_sBIT(png_const_structrp png_ptr, png_inforp info_ptr,
+ png_const_color_8p sig_bit)
+{
+ png_debug1(1, "in %s storage function", "sBIT");
+
+ if (png_ptr == NULL || info_ptr == NULL || sig_bit == NULL)
+ return;
+
+ info_ptr->sig_bit = *sig_bit;
+ info_ptr->valid |= PNG_INFO_sBIT;
+}
+#endif
+
+#ifdef PNG_sRGB_SUPPORTED
+void PNGAPI
+png_set_sRGB(png_const_structrp png_ptr, png_inforp info_ptr, int srgb_intent)
+{
+ png_debug1(1, "in %s storage function", "sRGB");
+
+ if (png_ptr == NULL || info_ptr == NULL)
+ return;
+
+ (void)png_colorspace_set_sRGB(png_ptr, &info_ptr->colorspace, srgb_intent);
+ png_colorspace_sync_info(png_ptr, info_ptr);
+}
+
+void PNGAPI
+png_set_sRGB_gAMA_and_cHRM(png_const_structrp png_ptr, png_inforp info_ptr,
+ int srgb_intent)
+{
+ png_debug1(1, "in %s storage function", "sRGB_gAMA_and_cHRM");
+
+ if (png_ptr == NULL || info_ptr == NULL)
+ return;
+
+ if (png_colorspace_set_sRGB(png_ptr, &info_ptr->colorspace,
+ srgb_intent) != 0)
+ {
+ /* This causes the gAMA and cHRM to be written too */
+ info_ptr->colorspace.flags |=
+ PNG_COLORSPACE_FROM_gAMA|PNG_COLORSPACE_FROM_cHRM;
+ }
+
+ png_colorspace_sync_info(png_ptr, info_ptr);
+}
+#endif /* sRGB */
+
+
+#ifdef PNG_iCCP_SUPPORTED
+void PNGAPI
+png_set_iCCP(png_const_structrp png_ptr, png_inforp info_ptr,
+ png_const_charp name, int compression_type,
+ png_const_bytep profile, png_uint_32 proflen)
+{
+ png_charp new_iccp_name;
+ png_bytep new_iccp_profile;
+ png_size_t length;
+
+ png_debug1(1, "in %s storage function", "iCCP");
+
+ if (png_ptr == NULL || info_ptr == NULL || name == NULL || profile == NULL)
+ return;
+
+ if (compression_type != PNG_COMPRESSION_TYPE_BASE)
+ png_app_error(png_ptr, "Invalid iCCP compression method");
+
+ /* Set the colorspace first because this validates the profile; do not
+ * override previously set app cHRM or gAMA here (because likely as not the
+ * application knows better than libpng what the correct values are.) Pass
+ * the info_ptr color_type field to png_colorspace_set_ICC because in the
+ * write case it has not yet been stored in png_ptr.
+ */
+ {
+ int result = png_colorspace_set_ICC(png_ptr, &info_ptr->colorspace, name,
+ proflen, profile, info_ptr->color_type);
+
+ png_colorspace_sync_info(png_ptr, info_ptr);
+
+ /* Don't do any of the copying if the profile was bad, or inconsistent. */
+ if (result == 0)
+ return;
+
+ /* But do write the gAMA and cHRM chunks from the profile. */
+ info_ptr->colorspace.flags |=
+ PNG_COLORSPACE_FROM_gAMA|PNG_COLORSPACE_FROM_cHRM;
+ }
+
+ length = strlen(name)+1;
+ new_iccp_name = png_voidcast(png_charp, png_malloc_warn(png_ptr, length));
+
+ if (new_iccp_name == NULL)
+ {
+ png_benign_error(png_ptr, "Insufficient memory to process iCCP chunk");
+
+ return;
+ }
+
+ memcpy(new_iccp_name, name, length);
+ new_iccp_profile = png_voidcast(png_bytep,
+ png_malloc_warn(png_ptr, proflen));
+
+ if (new_iccp_profile == NULL)
+ {
+ png_free(png_ptr, new_iccp_name);
+ new_iccp_name = NULL;
+ png_benign_error(png_ptr,
+ "Insufficient memory to process iCCP profile");
+
+ return;
+ }
+
+ memcpy(new_iccp_profile, profile, proflen);
+
+ png_free_data(png_ptr, info_ptr, PNG_FREE_ICCP, 0);
+
+ info_ptr->iccp_proflen = proflen;
+ info_ptr->iccp_name = new_iccp_name;
+ info_ptr->iccp_profile = new_iccp_profile;
+ info_ptr->free_me |= PNG_FREE_ICCP;
+ info_ptr->valid |= PNG_INFO_iCCP;
+}
+#endif
+
+#ifdef PNG_TEXT_SUPPORTED
+void PNGAPI
+png_set_text(png_const_structrp png_ptr, png_inforp info_ptr,
+ png_const_textp text_ptr, int num_text)
+{
+ int ret;
+ ret = png_set_text_2(png_ptr, info_ptr, text_ptr, num_text);
+
+ if (ret != 0)
+ png_error(png_ptr, "Insufficient memory to store text");
+}
+
+int /* PRIVATE */
+png_set_text_2(png_const_structrp png_ptr, png_inforp info_ptr,
+ png_const_textp text_ptr, int num_text)
+{
+ int i;
+
+ png_debug1(1, "in %lx storage function", png_ptr == NULL ? "unexpected" :
+ (unsigned long)png_ptr->chunk_name);
+
+ if (png_ptr == NULL || info_ptr == NULL || num_text <= 0 || text_ptr == NULL)
+ return(0);
+
+ /* Make sure we have enough space in the "text" array in info_struct
+ * to hold all of the incoming text_ptr objects. This compare can't overflow
+ * because max_text >= num_text (anyway, subtract of two positive integers
+ * can't overflow in any case.)
+ */
+ if (num_text > info_ptr->max_text - info_ptr->num_text)
+ {
+ int old_num_text = info_ptr->num_text;
+ int max_text;
+ png_textp new_text = NULL;
+
+ /* Calculate an appropriate max_text, checking for overflow. */
+ max_text = old_num_text;
+ if (num_text <= INT_MAX - max_text)
+ {
+ max_text += num_text;
+
+ /* Round up to a multiple of 8 */
+ if (max_text < INT_MAX-8)
+ max_text = (max_text + 8) & ~0x7;
+
+ else
+ max_text = INT_MAX;
+
+ /* Now allocate a new array and copy the old members in; this does all
+ * the overflow checks.
+ */
+ new_text = png_voidcast(png_textp,png_realloc_array(png_ptr,
+ info_ptr->text, old_num_text, max_text-old_num_text,
+ sizeof *new_text));
+ }
+
+ if (new_text == NULL)
+ {
+ png_chunk_report(png_ptr, "too many text chunks",
+ PNG_CHUNK_WRITE_ERROR);
+
+ return 1;
+ }
+
+ png_free(png_ptr, info_ptr->text);
+
+ info_ptr->text = new_text;
+ info_ptr->free_me |= PNG_FREE_TEXT;
+ info_ptr->max_text = max_text;
+ /* num_text is adjusted below as the entries are copied in */
+
+ png_debug1(3, "allocated %d entries for info_ptr->text", max_text);
+ }
+
+ for (i = 0; i < num_text; i++)
+ {
+ size_t text_length, key_len;
+ size_t lang_len, lang_key_len;
+ png_textp textp = &(info_ptr->text[info_ptr->num_text]);
+
+ if (text_ptr[i].key == NULL)
+ continue;
+
+ if (text_ptr[i].compression < PNG_TEXT_COMPRESSION_NONE ||
+ text_ptr[i].compression >= PNG_TEXT_COMPRESSION_LAST)
+ {
+ png_chunk_report(png_ptr, "text compression mode is out of range",
+ PNG_CHUNK_WRITE_ERROR);
+ continue;
+ }
+
+ key_len = strlen(text_ptr[i].key);
+
+ if (text_ptr[i].compression <= 0)
+ {
+ lang_len = 0;
+ lang_key_len = 0;
+ }
+
+ else
+# ifdef PNG_iTXt_SUPPORTED
+ {
+ /* Set iTXt data */
+
+ if (text_ptr[i].lang != NULL)
+ lang_len = strlen(text_ptr[i].lang);
+
+ else
+ lang_len = 0;
+
+ if (text_ptr[i].lang_key != NULL)
+ lang_key_len = strlen(text_ptr[i].lang_key);
+
+ else
+ lang_key_len = 0;
+ }
+# else /* iTXt */
+ {
+ png_chunk_report(png_ptr, "iTXt chunk not supported",
+ PNG_CHUNK_WRITE_ERROR);
+ continue;
+ }
+# endif
+
+ if (text_ptr[i].text == NULL || text_ptr[i].text[0] == '\0')
+ {
+ text_length = 0;
+# ifdef PNG_iTXt_SUPPORTED
+ if (text_ptr[i].compression > 0)
+ textp->compression = PNG_ITXT_COMPRESSION_NONE;
+
+ else
+# endif
+ textp->compression = PNG_TEXT_COMPRESSION_NONE;
+ }
+
+ else
+ {
+ text_length = strlen(text_ptr[i].text);
+ textp->compression = text_ptr[i].compression;
+ }
+
+ textp->key = png_voidcast(png_charp,png_malloc_base(png_ptr,
+ key_len + text_length + lang_len + lang_key_len + 4));
+
+ if (textp->key == NULL)
+ {
+ png_chunk_report(png_ptr, "text chunk: out of memory",
+ PNG_CHUNK_WRITE_ERROR);
+
+ return 1;
+ }
+
+ png_debug2(2, "Allocated %lu bytes at %p in png_set_text",
+ (unsigned long)(png_uint_32)
+ (key_len + lang_len + lang_key_len + text_length + 4),
+ textp->key);
+
+ memcpy(textp->key, text_ptr[i].key, key_len);
+ *(textp->key + key_len) = '\0';
+
+ if (text_ptr[i].compression > 0)
+ {
+ textp->lang = textp->key + key_len + 1;
+ memcpy(textp->lang, text_ptr[i].lang, lang_len);
+ *(textp->lang + lang_len) = '\0';
+ textp->lang_key = textp->lang + lang_len + 1;
+ memcpy(textp->lang_key, text_ptr[i].lang_key, lang_key_len);
+ *(textp->lang_key + lang_key_len) = '\0';
+ textp->text = textp->lang_key + lang_key_len + 1;
+ }
+
+ else
+ {
+ textp->lang=NULL;
+ textp->lang_key=NULL;
+ textp->text = textp->key + key_len + 1;
+ }
+
+ if (text_length != 0)
+ memcpy(textp->text, text_ptr[i].text, text_length);
+
+ *(textp->text + text_length) = '\0';
+
+# ifdef PNG_iTXt_SUPPORTED
+ if (textp->compression > 0)
+ {
+ textp->text_length = 0;
+ textp->itxt_length = text_length;
+ }
+
+ else
+# endif
+ {
+ textp->text_length = text_length;
+ textp->itxt_length = 0;
+ }
+
+ info_ptr->num_text++;
+ png_debug1(3, "transferred text chunk %d", info_ptr->num_text);
+ }
+
+ return(0);
+}
+#endif
+
+#ifdef PNG_tIME_SUPPORTED
+void PNGAPI
+png_set_tIME(png_const_structrp png_ptr, png_inforp info_ptr,
+ png_const_timep mod_time)
+{
+ png_debug1(1, "in %s storage function", "tIME");
+
+ if (png_ptr == NULL || info_ptr == NULL || mod_time == NULL ||
+ (png_ptr->mode & PNG_WROTE_tIME) != 0)
+ return;
+
+ if (mod_time->month == 0 || mod_time->month > 12 ||
+ mod_time->day == 0 || mod_time->day > 31 ||
+ mod_time->hour > 23 || mod_time->minute > 59 ||
+ mod_time->second > 60)
+ {
+ png_warning(png_ptr, "Ignoring invalid time value");
+
+ return;
+ }
+
+ info_ptr->mod_time = *mod_time;
+ info_ptr->valid |= PNG_INFO_tIME;
+}
+#endif
+
+#ifdef PNG_tRNS_SUPPORTED
+void PNGAPI
+png_set_tRNS(png_structrp png_ptr, png_inforp info_ptr,
+ png_const_bytep trans_alpha, int num_trans, png_const_color_16p trans_color)
+{
+ png_debug1(1, "in %s storage function", "tRNS");
+
+ if (png_ptr == NULL || info_ptr == NULL)
+
+ return;
+
+ if (trans_alpha != NULL)
+ {
+ /* It may not actually be necessary to set png_ptr->trans_alpha here;
+ * we do it for backward compatibility with the way the png_handle_tRNS
+ * function used to do the allocation.
+ *
+ * 1.6.0: The above statement is incorrect; png_handle_tRNS effectively
+ * relies on png_set_tRNS storing the information in png_struct
+ * (otherwise it won't be there for the code in pngrtran.c).
+ */
+
+ png_free_data(png_ptr, info_ptr, PNG_FREE_TRNS, 0);
+
+ /* Changed from num_trans to PNG_MAX_PALETTE_LENGTH in version 1.2.1 */
+ png_ptr->trans_alpha = info_ptr->trans_alpha = png_voidcast(png_bytep,
+ png_malloc(png_ptr, PNG_MAX_PALETTE_LENGTH));
+
+ if (num_trans > 0 && num_trans <= PNG_MAX_PALETTE_LENGTH)
+ memcpy(info_ptr->trans_alpha, trans_alpha, (png_size_t)num_trans);
+ }
+
+ if (trans_color != NULL)
+ {
+#ifdef PNG_WARNINGS_SUPPORTED
+ if (info_ptr->bit_depth < 16)
+ {
+ int sample_max = (1 << info_ptr->bit_depth) - 1;
+
+ if ((info_ptr->color_type == PNG_COLOR_TYPE_GRAY &&
+ trans_color->gray > sample_max) ||
+ (info_ptr->color_type == PNG_COLOR_TYPE_RGB &&
+ (trans_color->red > sample_max ||
+ trans_color->green > sample_max ||
+ trans_color->blue > sample_max)))
+ png_warning(png_ptr,
+ "tRNS chunk has out-of-range samples for bit_depth");
+ }
+#endif
+
+ info_ptr->trans_color = *trans_color;
+
+ if (num_trans == 0)
+ num_trans = 1;
+ }
+
+ info_ptr->num_trans = (png_uint_16)num_trans;
+
+ if (num_trans != 0)
+ {
+ info_ptr->valid |= PNG_INFO_tRNS;
+ info_ptr->free_me |= PNG_FREE_TRNS;
+ }
+}
+#endif
+
+#ifdef PNG_sPLT_SUPPORTED
+void PNGAPI
+png_set_sPLT(png_const_structrp png_ptr,
+ png_inforp info_ptr, png_const_sPLT_tp entries, int nentries)
+/*
+ * entries - array of png_sPLT_t structures
+ * to be added to the list of palettes
+ * in the info structure.
+ *
+ * nentries - number of palette structures to be
+ * added.
+ */
+{
+ png_sPLT_tp np;
+
+ if (png_ptr == NULL || info_ptr == NULL || nentries <= 0 || entries == NULL)
+ return;
+
+ /* Use the internal realloc function, which checks for all the possible
+ * overflows. Notice that the parameters are (int) and (size_t)
+ */
+ np = png_voidcast(png_sPLT_tp,png_realloc_array(png_ptr,
+ info_ptr->splt_palettes, info_ptr->splt_palettes_num, nentries,
+ sizeof *np));
+
+ if (np == NULL)
+ {
+ /* Out of memory or too many chunks */
+ png_chunk_report(png_ptr, "too many sPLT chunks", PNG_CHUNK_WRITE_ERROR);
+
+ return;
+ }
+
+ png_free(png_ptr, info_ptr->splt_palettes);
+ info_ptr->splt_palettes = np;
+ info_ptr->free_me |= PNG_FREE_SPLT;
+
+ np += info_ptr->splt_palettes_num;
+
+ do
+ {
+ png_size_t length;
+
+ /* Skip invalid input entries */
+ if (entries->name == NULL || entries->entries == NULL)
+ {
+ /* png_handle_sPLT doesn't do this, so this is an app error */
+ png_app_error(png_ptr, "png_set_sPLT: invalid sPLT");
+ /* Just skip the invalid entry */
+ continue;
+ }
+
+ np->depth = entries->depth;
+
+ /* In the event of out-of-memory just return - there's no point keeping
+ * on trying to add sPLT chunks.
+ */
+ length = strlen(entries->name) + 1;
+ np->name = png_voidcast(png_charp, png_malloc_base(png_ptr, length));
+
+ if (np->name == NULL)
+ break;
+
+ memcpy(np->name, entries->name, length);
+
+ /* IMPORTANT: we have memory now that won't get freed if something else
+ * goes wrong; this code must free it. png_malloc_array produces no
+ * warnings; use a png_chunk_report (below) if there is an error.
+ */
+ np->entries = png_voidcast(png_sPLT_entryp, png_malloc_array(png_ptr,
+ entries->nentries, sizeof (png_sPLT_entry)));
+
+ if (np->entries == NULL)
+ {
+ png_free(png_ptr, np->name);
+ np->name = NULL;
+ break;
+ }
+
+ np->nentries = entries->nentries;
+ /* This multiply can't overflow because png_malloc_array has already
+ * checked it when doing the allocation.
+ */
+ memcpy(np->entries, entries->entries,
+ entries->nentries * sizeof (png_sPLT_entry));
+
+ /* Note that 'continue' skips the advance of the out pointer and out
+ * count, so an invalid entry is not added.
+ */
+ info_ptr->valid |= PNG_INFO_sPLT;
+ ++(info_ptr->splt_palettes_num);
+ ++np;
+ }
+ while (++entries, --nentries);
+
+ if (nentries > 0)
+ png_chunk_report(png_ptr, "sPLT out of memory", PNG_CHUNK_WRITE_ERROR);
+}
+#endif /* sPLT */
+
+#ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED
+static png_byte
+check_location(png_const_structrp png_ptr, int location)
+{
+ location &= (PNG_HAVE_IHDR|PNG_HAVE_PLTE|PNG_AFTER_IDAT);
+
+ /* New in 1.6.0; copy the location and check it. This is an API
+ * change; previously the app had to use the
+ * png_set_unknown_chunk_location API below for each chunk.
+ */
+ if (location == 0 && (png_ptr->mode & PNG_IS_READ_STRUCT) == 0)
+ {
+ /* Write struct, so unknown chunks come from the app */
+ png_app_warning(png_ptr,
+ "png_set_unknown_chunks now expects a valid location");
+ /* Use the old behavior */
+ location = (png_byte)(png_ptr->mode &
+ (PNG_HAVE_IHDR|PNG_HAVE_PLTE|PNG_AFTER_IDAT));
+ }
+
+ /* This need not be an internal error - if the app calls
+ * png_set_unknown_chunks on a read pointer it must get the location right.
+ */
+ if (location == 0)
+ png_error(png_ptr, "invalid location in png_set_unknown_chunks");
+
+ /* Now reduce the location to the top-most set bit by removing each least
+ * significant bit in turn.
+ */
+ while (location != (location & -location))
+ location &= ~(location & -location);
+
+ /* The cast is safe because 'location' is a bit mask and only the low four
+ * bits are significant.
+ */
+ return (png_byte)location;
+}
+
+void PNGAPI
+png_set_unknown_chunks(png_const_structrp png_ptr,
+ png_inforp info_ptr, png_const_unknown_chunkp unknowns, int num_unknowns)
+{
+ png_unknown_chunkp np;
+
+ if (png_ptr == NULL || info_ptr == NULL || num_unknowns <= 0 ||
+ unknowns == NULL)
+ return;
+
+ /* Check for the failure cases where support has been disabled at compile
+ * time. This code is hardly ever compiled - it's here because
+ * STORE_UNKNOWN_CHUNKS is set by both read and write code (compiling in this
+ * code) but may be meaningless if the read or write handling of unknown
+ * chunks is not compiled in.
+ */
+# if !defined(PNG_READ_UNKNOWN_CHUNKS_SUPPORTED) && \
+ defined(PNG_READ_SUPPORTED)
+ if ((png_ptr->mode & PNG_IS_READ_STRUCT) != 0)
+ {
+ png_app_error(png_ptr, "no unknown chunk support on read");
+
+ return;
+ }
+# endif
+# if !defined(PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED) && \
+ defined(PNG_WRITE_SUPPORTED)
+ if ((png_ptr->mode & PNG_IS_READ_STRUCT) == 0)
+ {
+ png_app_error(png_ptr, "no unknown chunk support on write");
+
+ return;
+ }
+# endif
+
+ /* Prior to 1.6.0 this code used png_malloc_warn; however, this meant that
+ * unknown critical chunks could be lost with just a warning resulting in
+ * undefined behavior. Now png_chunk_report is used to provide behavior
+ * appropriate to read or write.
+ */
+ np = png_voidcast(png_unknown_chunkp, png_realloc_array(png_ptr,
+ info_ptr->unknown_chunks, info_ptr->unknown_chunks_num, num_unknowns,
+ sizeof *np));
+
+ if (np == NULL)
+ {
+ png_chunk_report(png_ptr, "too many unknown chunks",
+ PNG_CHUNK_WRITE_ERROR);
+
+ return;
+ }
+
+ png_free(png_ptr, info_ptr->unknown_chunks);
+ info_ptr->unknown_chunks = np; /* safe because it is initialized */
+ info_ptr->free_me |= PNG_FREE_UNKN;
+
+ np += info_ptr->unknown_chunks_num;
+
+ /* Increment unknown_chunks_num each time round the loop to protect the
+ * just-allocated chunk data.
+ */
+ for (; num_unknowns > 0; --num_unknowns, ++unknowns)
+ {
+ memcpy(np->name, unknowns->name, (sizeof np->name));
+ np->name[(sizeof np->name)-1] = '\0';
+ np->location = check_location(png_ptr, unknowns->location);
+
+ if (unknowns->size == 0)
+ {
+ np->data = NULL;
+ np->size = 0;
+ }
+
+ else
+ {
+ np->data = png_voidcast(png_bytep,
+ png_malloc_base(png_ptr, unknowns->size));
+
+ if (np->data == NULL)
+ {
+ png_chunk_report(png_ptr, "unknown chunk: out of memory",
+ PNG_CHUNK_WRITE_ERROR);
+ /* But just skip storing the unknown chunk */
+ continue;
+ }
+
+ memcpy(np->data, unknowns->data, unknowns->size);
+ np->size = unknowns->size;
+ }
+
+ /* These increments are skipped on out-of-memory for the data - the
+ * unknown chunk entry gets overwritten if the png_chunk_report returns.
+ * This is correct in the read case (the chunk is just dropped.)
+ */
+ ++np;
+ ++(info_ptr->unknown_chunks_num);
+ }
+}
+
+void PNGAPI
+png_set_unknown_chunk_location(png_const_structrp png_ptr, png_inforp info_ptr,
+ int chunk, int location)
+{
+ /* This API is pretty pointless in 1.6.0 because the location can be set
+ * before the call to png_set_unknown_chunks.
+ *
+ * TODO: add a png_app_warning in 1.7
+ */
+ if (png_ptr != NULL && info_ptr != NULL && chunk >= 0 &&
+ chunk < info_ptr->unknown_chunks_num)
+ {
+ if ((location & (PNG_HAVE_IHDR|PNG_HAVE_PLTE|PNG_AFTER_IDAT)) == 0)
+ {
+ png_app_error(png_ptr, "invalid unknown chunk location");
+ /* Fake out the pre 1.6.0 behavior: */
+ if ((location & PNG_HAVE_IDAT) != 0) /* undocumented! */
+ location = PNG_AFTER_IDAT;
+
+ else
+ location = PNG_HAVE_IHDR; /* also undocumented */
+ }
+
+ info_ptr->unknown_chunks[chunk].location =
+ check_location(png_ptr, location);
+ }
+}
+#endif /* STORE_UNKNOWN_CHUNKS */
+
+#ifdef PNG_MNG_FEATURES_SUPPORTED
+png_uint_32 PNGAPI
+png_permit_mng_features (png_structrp png_ptr, png_uint_32 mng_features)
+{
+ png_debug(1, "in png_permit_mng_features");
+
+ if (png_ptr == NULL)
+ return 0;
+
+ png_ptr->mng_features_permitted = mng_features & PNG_ALL_MNG_FEATURES;
+
+ return png_ptr->mng_features_permitted;
+}
+#endif
+
+#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
+static unsigned int
+add_one_chunk(png_bytep list, unsigned int count, png_const_bytep add, int keep)
+{
+ unsigned int i;
+
+ /* Utility function: update the 'keep' state of a chunk if it is already in
+ * the list, otherwise add it to the list.
+ */
+ for (i=0; i<count; ++i, list += 5)
+ {
+ if (memcmp(list, add, 4) == 0)
+ {
+ list[4] = (png_byte)keep;
+
+ return count;
+ }
+ }
+
+ if (keep != PNG_HANDLE_CHUNK_AS_DEFAULT)
+ {
+ ++count;
+ memcpy(list, add, 4);
+ list[4] = (png_byte)keep;
+ }
+
+ return count;
+}
+
+void PNGAPI
+png_set_keep_unknown_chunks(png_structrp png_ptr, int keep,
+ png_const_bytep chunk_list, int num_chunks_in)
+{
+ png_bytep new_list;
+ unsigned int num_chunks, old_num_chunks;
+
+ if (png_ptr == NULL)
+ return;
+
+ if (keep < 0 || keep >= PNG_HANDLE_CHUNK_LAST)
+ {
+ png_app_error(png_ptr, "png_set_keep_unknown_chunks: invalid keep");
+
+ return;
+ }
+
+ if (num_chunks_in <= 0)
+ {
+ png_ptr->unknown_default = keep;
+
+ /* '0' means just set the flags, so stop here */
+ if (num_chunks_in == 0)
+ return;
+ }
+
+ if (num_chunks_in < 0)
+ {
+ /* Ignore all unknown chunks and all chunks recognized by
+ * libpng except for IHDR, PLTE, tRNS, IDAT, and IEND
+ */
+ static PNG_CONST png_byte chunks_to_ignore[] = {
+ 98, 75, 71, 68, '\0', /* bKGD */
+ 99, 72, 82, 77, '\0', /* cHRM */
+ 103, 65, 77, 65, '\0', /* gAMA */
+ 104, 73, 83, 84, '\0', /* hIST */
+ 105, 67, 67, 80, '\0', /* iCCP */
+ 105, 84, 88, 116, '\0', /* iTXt */
+ 111, 70, 70, 115, '\0', /* oFFs */
+ 112, 67, 65, 76, '\0', /* pCAL */
+ 112, 72, 89, 115, '\0', /* pHYs */
+ 115, 66, 73, 84, '\0', /* sBIT */
+ 115, 67, 65, 76, '\0', /* sCAL */
+ 115, 80, 76, 84, '\0', /* sPLT */
+ 115, 84, 69, 82, '\0', /* sTER */
+ 115, 82, 71, 66, '\0', /* sRGB */
+ 116, 69, 88, 116, '\0', /* tEXt */
+ 116, 73, 77, 69, '\0', /* tIME */
+ 122, 84, 88, 116, '\0' /* zTXt */
+ };
+
+ chunk_list = chunks_to_ignore;
+ num_chunks = (unsigned int)/*SAFE*/(sizeof chunks_to_ignore)/5U;
+ }
+
+ else /* num_chunks_in > 0 */
+ {
+ if (chunk_list == NULL)
+ {
+ /* Prior to 1.6.0 this was silently ignored, now it is an app_error
+ * which can be switched off.
+ */
+ png_app_error(png_ptr, "png_set_keep_unknown_chunks: no chunk list");
+
+ return;
+ }
+
+ num_chunks = num_chunks_in;
+ }
+
+ old_num_chunks = png_ptr->num_chunk_list;
+ if (png_ptr->chunk_list == NULL)
+ old_num_chunks = 0;
+
+ /* Since num_chunks is always restricted to UINT_MAX/5 this can't overflow.
+ */
+ if (num_chunks + old_num_chunks > UINT_MAX/5)
+ {
+ png_app_error(png_ptr, "png_set_keep_unknown_chunks: too many chunks");
+
+ return;
+ }
+
+ /* If these chunks are being reset to the default then no more memory is
+ * required because add_one_chunk above doesn't extend the list if the 'keep'
+ * parameter is the default.
+ */
+ if (keep != 0)
+ {
+ new_list = png_voidcast(png_bytep, png_malloc(png_ptr,
+ 5 * (num_chunks + old_num_chunks)));
+
+ if (old_num_chunks > 0)
+ memcpy(new_list, png_ptr->chunk_list, 5*old_num_chunks);
+ }
+
+ else if (old_num_chunks > 0)
+ new_list = png_ptr->chunk_list;
+
+ else
+ new_list = NULL;
+
+ /* Add the new chunks together with each one's handling code. If the chunk
+ * already exists the code is updated, otherwise the chunk is added to the
+ * end. (In libpng 1.6.0 order no longer matters because this code enforces
+ * the earlier convention that the last setting is the one that is used.)
+ */
+ if (new_list != NULL)
+ {
+ png_const_bytep inlist;
+ png_bytep outlist;
+ unsigned int i;
+
+ for (i=0; i<num_chunks; ++i)
+ {
+ old_num_chunks = add_one_chunk(new_list, old_num_chunks,
+ chunk_list+5*i, keep);
+ }
+
+ /* Now remove any spurious 'default' entries. */
+ num_chunks = 0;
+ for (i=0, inlist=outlist=new_list; i<old_num_chunks; ++i, inlist += 5)
+ {
+ if (inlist[4])
+ {
+ if (outlist != inlist)
+ memcpy(outlist, inlist, 5);
+ outlist += 5;
+ ++num_chunks;
+ }
+ }
+
+ /* This means the application has removed all the specialized handling. */
+ if (num_chunks == 0)
+ {
+ if (png_ptr->chunk_list != new_list)
+ png_free(png_ptr, new_list);
+
+ new_list = NULL;
+ }
+ }
+
+ else
+ num_chunks = 0;
+
+ png_ptr->num_chunk_list = num_chunks;
+
+ if (png_ptr->chunk_list != new_list)
+ {
+ if (png_ptr->chunk_list != NULL)
+ png_free(png_ptr, png_ptr->chunk_list);
+
+ png_ptr->chunk_list = new_list;
+ }
+}
+#endif
+
+#ifdef PNG_READ_USER_CHUNKS_SUPPORTED
+void PNGAPI
+png_set_read_user_chunk_fn(png_structrp png_ptr, png_voidp user_chunk_ptr,
+ png_user_chunk_ptr read_user_chunk_fn)
+{
+ png_debug(1, "in png_set_read_user_chunk_fn");
+
+ if (png_ptr == NULL)
+ return;
+
+ png_ptr->read_user_chunk_fn = read_user_chunk_fn;
+ png_ptr->user_chunk_ptr = user_chunk_ptr;
+}
+#endif
+
+#ifdef PNG_INFO_IMAGE_SUPPORTED
+void PNGAPI
+png_set_rows(png_const_structrp png_ptr, png_inforp info_ptr,
+ png_bytepp row_pointers)
+{
+ png_debug1(1, "in %s storage function", "rows");
+
+ if (png_ptr == NULL || info_ptr == NULL)
+ return;
+
+ if (info_ptr->row_pointers != NULL &&
+ (info_ptr->row_pointers != row_pointers))
+ png_free_data(png_ptr, info_ptr, PNG_FREE_ROWS, 0);
+
+ info_ptr->row_pointers = row_pointers;
+
+ if (row_pointers != NULL)
+ info_ptr->valid |= PNG_INFO_IDAT;
+}
+#endif
+
+void PNGAPI
+png_set_compression_buffer_size(png_structrp png_ptr, png_size_t size)
+{
+ if (png_ptr == NULL)
+ return;
+
+ if (size == 0 || size > PNG_UINT_31_MAX)
+ png_error(png_ptr, "invalid compression buffer size");
+
+# ifdef PNG_SEQUENTIAL_READ_SUPPORTED
+ if ((png_ptr->mode & PNG_IS_READ_STRUCT) != 0)
+ {
+ png_ptr->IDAT_read_size = (png_uint_32)size; /* checked above */
+ return;
+ }
+# endif
+
+# ifdef PNG_WRITE_SUPPORTED
+ if ((png_ptr->mode & PNG_IS_READ_STRUCT) == 0)
+ {
+ if (png_ptr->zowner != 0)
+ {
+ png_warning(png_ptr,
+ "Compression buffer size cannot be changed because it is in use");
+
+ return;
+ }
+
+#ifndef __COVERITY__
+ if (size > ZLIB_IO_MAX)
+ {
+ png_warning(png_ptr,
+ "Compression buffer size limited to system maximum");
+ size = ZLIB_IO_MAX; /* must fit */
+ }
+#endif
+
+ if (size < 6)
+ {
+ /* Deflate will potentially go into an infinite loop on a SYNC_FLUSH
+ * if this is permitted.
+ */
+ png_warning(png_ptr,
+ "Compression buffer size cannot be reduced below 6");
+
+ return;
+ }
+
+ if (png_ptr->zbuffer_size != size)
+ {
+ png_free_buffer_list(png_ptr, &png_ptr->zbuffer_list);
+ png_ptr->zbuffer_size = (uInt)size;
+ }
+ }
+# endif
+}
+
+void PNGAPI
+png_set_invalid(png_const_structrp png_ptr, png_inforp info_ptr, int mask)
+{
+ if (png_ptr != NULL && info_ptr != NULL)
+ info_ptr->valid &= ~mask;
+}
+
+
+#ifdef PNG_SET_USER_LIMITS_SUPPORTED
+/* This function was added to libpng 1.2.6 */
+void PNGAPI
+png_set_user_limits (png_structrp png_ptr, png_uint_32 user_width_max,
+ png_uint_32 user_height_max)
+{
+ /* Images with dimensions larger than these limits will be
+ * rejected by png_set_IHDR(). To accept any PNG datastream
+ * regardless of dimensions, set both limits to 0x7ffffffL.
+ */
+ if (png_ptr == NULL)
+ return;
+
+ png_ptr->user_width_max = user_width_max;
+ png_ptr->user_height_max = user_height_max;
+}
+
+/* This function was added to libpng 1.4.0 */
+void PNGAPI
+png_set_chunk_cache_max (png_structrp png_ptr, png_uint_32 user_chunk_cache_max)
+{
+ if (png_ptr != NULL)
+ png_ptr->user_chunk_cache_max = user_chunk_cache_max;
+}
+
+/* This function was added to libpng 1.4.1 */
+void PNGAPI
+png_set_chunk_malloc_max (png_structrp png_ptr,
+ png_alloc_size_t user_chunk_malloc_max)
+{
+ if (png_ptr != NULL)
+ png_ptr->user_chunk_malloc_max = user_chunk_malloc_max;
+}
+#endif /* ?SET_USER_LIMITS */
+
+
+#ifdef PNG_BENIGN_ERRORS_SUPPORTED
+void PNGAPI
+png_set_benign_errors(png_structrp png_ptr, int allowed)
+{
+ png_debug(1, "in png_set_benign_errors");
+
+ /* If allowed is 1, png_benign_error() is treated as a warning.
+ *
+ * If allowed is 0, png_benign_error() is treated as an error (which
+ * is the default behavior if png_set_benign_errors() is not called).
+ */
+
+ if (allowed != 0)
+ png_ptr->flags |= PNG_FLAG_BENIGN_ERRORS_WARN |
+ PNG_FLAG_APP_WARNINGS_WARN | PNG_FLAG_APP_ERRORS_WARN;
+
+ else
+ png_ptr->flags &= ~(PNG_FLAG_BENIGN_ERRORS_WARN |
+ PNG_FLAG_APP_WARNINGS_WARN | PNG_FLAG_APP_ERRORS_WARN);
+}
+#endif /* BENIGN_ERRORS */
+
+#ifdef PNG_CHECK_FOR_INVALID_INDEX_SUPPORTED
+ /* Whether to report invalid palette index; added at libng-1.5.10.
+ * It is possible for an indexed (color-type==3) PNG file to contain
+ * pixels with invalid (out-of-range) indexes if the PLTE chunk has
+ * fewer entries than the image's bit-depth would allow. We recover
+ * from this gracefully by filling any incomplete palette with zeros
+ * (opaque black). By default, when this occurs libpng will issue
+ * a benign error. This API can be used to override that behavior.
+ */
+void PNGAPI
+png_set_check_for_invalid_index(png_structrp png_ptr, int allowed)
+{
+ png_debug(1, "in png_set_check_for_invalid_index");
+
+ if (allowed > 0)
+ png_ptr->num_palette_max = 0;
+
+ else
+ png_ptr->num_palette_max = -1;
+}
+#endif
+#endif /* READ || WRITE */
--- /dev/null
+
+/* pngstruct.h - header file for PNG reference library
+ *
+ * Last changed in libpng 1.6.1 [March 28, 2013]
+ * Copyright (c) 1998-2013 Glenn Randers-Pehrson
+ * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
+ * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ */
+
+/* The structure that holds the information to read and write PNG files.
+ * The only people who need to care about what is inside of this are the
+ * people who will be modifying the library for their own special needs.
+ * It should NOT be accessed directly by an application.
+ */
+
+#ifndef PNGSTRUCT_H
+#define PNGSTRUCT_H
+/* zlib.h defines the structure z_stream, an instance of which is included
+ * in this structure and is required for decompressing the LZ compressed
+ * data in PNG files.
+ */
+#ifndef ZLIB_CONST
+ /* We must ensure that zlib uses 'const' in declarations. */
+# define ZLIB_CONST
+#endif
+#include "zlib.h"
+#ifdef const
+ /* zlib.h sometimes #defines const to nothing, undo this. */
+# undef const
+#endif
+
+/* zlib.h has mediocre z_const use before 1.2.6, this stuff is for compatibility
+ * with older builds.
+ */
+#if ZLIB_VERNUM < 0x1260
+# define PNGZ_MSG_CAST(s) png_constcast(char*,s)
+# define PNGZ_INPUT_CAST(b) png_constcast(png_bytep,b)
+#else
+# define PNGZ_MSG_CAST(s) (s)
+# define PNGZ_INPUT_CAST(b) (b)
+#endif
+
+/* zlib.h declares a magic type 'uInt' that limits the amount of data that zlib
+ * can handle at once. This type need be no larger than 16 bits (so maximum of
+ * 65535), this define allows us to discover how big it is, but limited by the
+ * maximuum for png_size_t. The value can be overriden in a library build
+ * (pngusr.h, or set it in CPPFLAGS) and it works to set it to a considerably
+ * lower value (e.g. 255 works). A lower value may help memory usage (slightly)
+ * and may even improve performance on some systems (and degrade it on others.)
+ */
+#ifndef ZLIB_IO_MAX
+# define ZLIB_IO_MAX ((uInt)-1)
+#endif
+
+#ifdef PNG_WRITE_SUPPORTED
+/* The type of a compression buffer list used by the write code. */
+typedef struct png_compression_buffer
+{
+ struct png_compression_buffer *next;
+ png_byte output[1]; /* actually zbuf_size */
+} png_compression_buffer, *png_compression_bufferp;
+
+#define PNG_COMPRESSION_BUFFER_SIZE(pp)\
+ (offsetof(png_compression_buffer, output) + (pp)->zbuffer_size)
+#endif
+
+/* Colorspace support; structures used in png_struct, png_info and in internal
+ * functions to hold and communicate information about the color space.
+ *
+ * PNG_COLORSPACE_SUPPORTED is only required if the application will perform
+ * colorspace corrections, otherwise all the colorspace information can be
+ * skipped and the size of libpng can be reduced (significantly) by compiling
+ * out the colorspace support.
+ */
+#ifdef PNG_COLORSPACE_SUPPORTED
+/* The chromaticities of the red, green and blue colorants and the chromaticity
+ * of the corresponding white point (i.e. of rgb(1.0,1.0,1.0)).
+ */
+typedef struct png_xy
+{
+ png_fixed_point redx, redy;
+ png_fixed_point greenx, greeny;
+ png_fixed_point bluex, bluey;
+ png_fixed_point whitex, whitey;
+} png_xy;
+
+/* The same data as above but encoded as CIE XYZ values. When this data comes
+ * from chromaticities the sum of the Y values is assumed to be 1.0
+ */
+typedef struct png_XYZ
+{
+ png_fixed_point red_X, red_Y, red_Z;
+ png_fixed_point green_X, green_Y, green_Z;
+ png_fixed_point blue_X, blue_Y, blue_Z;
+} png_XYZ;
+#endif /* COLORSPACE */
+
+#if defined(PNG_COLORSPACE_SUPPORTED) || defined(PNG_GAMMA_SUPPORTED)
+/* A colorspace is all the above plus, potentially, profile information;
+ * however at present libpng does not use the profile internally so it is only
+ * stored in the png_info struct (if iCCP is supported.) The rendering intent
+ * is retained here and is checked.
+ *
+ * The file gamma encoding information is also stored here and gamma correction
+ * is done by libpng, whereas color correction must currently be done by the
+ * application.
+ */
+typedef struct png_colorspace
+{
+#ifdef PNG_GAMMA_SUPPORTED
+ png_fixed_point gamma; /* File gamma */
+#endif
+
+#ifdef PNG_COLORSPACE_SUPPORTED
+ png_xy end_points_xy; /* End points as chromaticities */
+ png_XYZ end_points_XYZ; /* End points as CIE XYZ colorant values */
+ png_uint_16 rendering_intent; /* Rendering intent of a profile */
+#endif
+
+ /* Flags are always defined to simplify the code. */
+ png_uint_16 flags; /* As defined below */
+} png_colorspace, * PNG_RESTRICT png_colorspacerp;
+
+typedef const png_colorspace * PNG_RESTRICT png_const_colorspacerp;
+
+/* General flags for the 'flags' field */
+#define PNG_COLORSPACE_HAVE_GAMMA 0x0001
+#define PNG_COLORSPACE_HAVE_ENDPOINTS 0x0002
+#define PNG_COLORSPACE_HAVE_INTENT 0x0004
+#define PNG_COLORSPACE_FROM_gAMA 0x0008
+#define PNG_COLORSPACE_FROM_cHRM 0x0010
+#define PNG_COLORSPACE_FROM_sRGB 0x0020
+#define PNG_COLORSPACE_ENDPOINTS_MATCH_sRGB 0x0040
+#define PNG_COLORSPACE_MATCHES_sRGB 0x0080 /* exact match on profile */
+#define PNG_COLORSPACE_INVALID 0x8000
+#define PNG_COLORSPACE_CANCEL(flags) (0xffff ^ (flags))
+#endif /* COLORSPACE || GAMMA */
+
+struct png_struct_def
+{
+#ifdef PNG_SETJMP_SUPPORTED
+ jmp_buf jmp_buf_local; /* New name in 1.6.0 for jmp_buf in png_struct */
+ png_longjmp_ptr longjmp_fn;/* setjmp non-local goto function. */
+ jmp_buf *jmp_buf_ptr; /* passed to longjmp_fn */
+ size_t jmp_buf_size; /* size of the above, if allocated */
+#endif
+ png_error_ptr error_fn; /* function for printing errors and aborting */
+#ifdef PNG_WARNINGS_SUPPORTED
+ png_error_ptr warning_fn; /* function for printing warnings */
+#endif
+ png_voidp error_ptr; /* user supplied struct for error functions */
+ png_rw_ptr write_data_fn; /* function for writing output data */
+ png_rw_ptr read_data_fn; /* function for reading input data */
+ png_voidp io_ptr; /* ptr to application struct for I/O functions */
+
+#ifdef PNG_READ_USER_TRANSFORM_SUPPORTED
+ png_user_transform_ptr read_user_transform_fn; /* user read transform */
+#endif
+
+#ifdef PNG_WRITE_USER_TRANSFORM_SUPPORTED
+ png_user_transform_ptr write_user_transform_fn; /* user write transform */
+#endif
+
+/* These were added in libpng-1.0.2 */
+#ifdef PNG_USER_TRANSFORM_PTR_SUPPORTED
+#if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) || \
+ defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED)
+ png_voidp user_transform_ptr; /* user supplied struct for user transform */
+ png_byte user_transform_depth; /* bit depth of user transformed pixels */
+ png_byte user_transform_channels; /* channels in user transformed pixels */
+#endif
+#endif
+
+ png_uint_32 mode; /* tells us where we are in the PNG file */
+ png_uint_32 flags; /* flags indicating various things to libpng */
+ png_uint_32 transformations; /* which transformations to perform */
+
+ png_uint_32 zowner; /* ID (chunk type) of zstream owner, 0 if none */
+ z_stream zstream; /* decompression structure */
+
+#ifdef PNG_WRITE_SUPPORTED
+ png_compression_bufferp zbuffer_list; /* Created on demand during write */
+ uInt zbuffer_size; /* size of the actual buffer */
+
+ int zlib_level; /* holds zlib compression level */
+ int zlib_method; /* holds zlib compression method */
+ int zlib_window_bits; /* holds zlib compression window bits */
+ int zlib_mem_level; /* holds zlib compression memory level */
+ int zlib_strategy; /* holds zlib compression strategy */
+#endif
+/* Added at libpng 1.5.4 */
+#ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED
+ int zlib_text_level; /* holds zlib compression level */
+ int zlib_text_method; /* holds zlib compression method */
+ int zlib_text_window_bits; /* holds zlib compression window bits */
+ int zlib_text_mem_level; /* holds zlib compression memory level */
+ int zlib_text_strategy; /* holds zlib compression strategy */
+#endif
+/* End of material added at libpng 1.5.4 */
+/* Added at libpng 1.6.0 */
+#ifdef PNG_WRITE_SUPPORTED
+ int zlib_set_level; /* Actual values set into the zstream on write */
+ int zlib_set_method;
+ int zlib_set_window_bits;
+ int zlib_set_mem_level;
+ int zlib_set_strategy;
+#endif
+
+ png_uint_32 width; /* width of image in pixels */
+ png_uint_32 height; /* height of image in pixels */
+ png_uint_32 num_rows; /* number of rows in current pass */
+ png_uint_32 usr_width; /* width of row at start of write */
+ png_size_t rowbytes; /* size of row in bytes */
+ png_uint_32 iwidth; /* width of current interlaced row in pixels */
+ png_uint_32 row_number; /* current row in interlace pass */
+ png_uint_32 chunk_name; /* PNG_CHUNK() id of current chunk */
+ png_bytep prev_row; /* buffer to save previous (unfiltered) row.
+ * This is a pointer into big_prev_row
+ */
+ png_bytep row_buf; /* buffer to save current (unfiltered) row.
+ * This is a pointer into big_row_buf
+ */
+#ifdef PNG_WRITE_SUPPORTED
+ png_bytep sub_row; /* buffer to save "sub" row when filtering */
+ png_bytep up_row; /* buffer to save "up" row when filtering */
+ png_bytep avg_row; /* buffer to save "avg" row when filtering */
+ png_bytep paeth_row; /* buffer to save "Paeth" row when filtering */
+#endif
+ png_size_t info_rowbytes; /* Added in 1.5.4: cache of updated row bytes */
+
+ png_uint_32 idat_size; /* current IDAT size for read */
+ png_uint_32 crc; /* current chunk CRC value */
+ png_colorp palette; /* palette from the input file */
+ png_uint_16 num_palette; /* number of color entries in palette */
+
+/* Added at libpng-1.5.10 */
+#ifdef PNG_CHECK_FOR_INVALID_INDEX_SUPPORTED
+ int num_palette_max; /* maximum palette index found in IDAT */
+#endif
+
+ png_uint_16 num_trans; /* number of transparency values */
+ png_byte compression; /* file compression type (always 0) */
+ png_byte filter; /* file filter type (always 0) */
+ png_byte interlaced; /* PNG_INTERLACE_NONE, PNG_INTERLACE_ADAM7 */
+ png_byte pass; /* current interlace pass (0 - 6) */
+ png_byte do_filter; /* row filter flags (see PNG_FILTER_ below ) */
+ png_byte color_type; /* color type of file */
+ png_byte bit_depth; /* bit depth of file */
+ png_byte usr_bit_depth; /* bit depth of users row: write only */
+ png_byte pixel_depth; /* number of bits per pixel */
+ png_byte channels; /* number of channels in file */
+#ifdef PNG_WRITE_SUPPORTED
+ png_byte usr_channels; /* channels at start of write: write only */
+#endif
+ png_byte sig_bytes; /* magic bytes read/written from start of file */
+ png_byte maximum_pixel_depth;
+ /* pixel depth used for the row buffers */
+ png_byte transformed_pixel_depth;
+ /* pixel depth after read/write transforms */
+#if defined(PNG_READ_FILLER_SUPPORTED) || defined(PNG_WRITE_FILLER_SUPPORTED)
+ png_uint_16 filler; /* filler bytes for pixel expansion */
+#endif
+
+#if defined(PNG_bKGD_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED) ||\
+ defined(PNG_READ_ALPHA_MODE_SUPPORTED)
+ png_byte background_gamma_type;
+ png_fixed_point background_gamma;
+ png_color_16 background; /* background color in screen gamma space */
+#ifdef PNG_READ_GAMMA_SUPPORTED
+ png_color_16 background_1; /* background normalized to gamma 1.0 */
+#endif
+#endif /* bKGD */
+
+#ifdef PNG_WRITE_FLUSH_SUPPORTED
+ png_flush_ptr output_flush_fn; /* Function for flushing output */
+ png_uint_32 flush_dist; /* how many rows apart to flush, 0 - no flush */
+ png_uint_32 flush_rows; /* number of rows written since last flush */
+#endif
+
+#ifdef PNG_READ_GAMMA_SUPPORTED
+ int gamma_shift; /* number of "insignificant" bits in 16-bit gamma */
+ png_fixed_point screen_gamma; /* screen gamma value (display_exponent) */
+
+ png_bytep gamma_table; /* gamma table for 8-bit depth files */
+ png_uint_16pp gamma_16_table; /* gamma table for 16-bit depth files */
+#if defined(PNG_READ_BACKGROUND_SUPPORTED) || \
+ defined(PNG_READ_ALPHA_MODE_SUPPORTED) || \
+ defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)
+ png_bytep gamma_from_1; /* converts from 1.0 to screen */
+ png_bytep gamma_to_1; /* converts from file to 1.0 */
+ png_uint_16pp gamma_16_from_1; /* converts from 1.0 to screen */
+ png_uint_16pp gamma_16_to_1; /* converts from file to 1.0 */
+#endif /* READ_BACKGROUND || READ_ALPHA_MODE || RGB_TO_GRAY */
+#endif
+
+#if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_sBIT_SUPPORTED)
+ png_color_8 sig_bit; /* significant bits in each available channel */
+#endif
+
+#if defined(PNG_READ_SHIFT_SUPPORTED) || defined(PNG_WRITE_SHIFT_SUPPORTED)
+ png_color_8 shift; /* shift for significant bit tranformation */
+#endif
+
+#if defined(PNG_tRNS_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED) \
+ || defined(PNG_READ_EXPAND_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
+ png_bytep trans_alpha; /* alpha values for paletted files */
+ png_color_16 trans_color; /* transparent color for non-paletted files */
+#endif
+
+ png_read_status_ptr read_row_fn; /* called after each row is decoded */
+ png_write_status_ptr write_row_fn; /* called after each row is encoded */
+#ifdef PNG_PROGRESSIVE_READ_SUPPORTED
+ png_progressive_info_ptr info_fn; /* called after header data fully read */
+ png_progressive_row_ptr row_fn; /* called after a prog. row is decoded */
+ png_progressive_end_ptr end_fn; /* called after image is complete */
+ png_bytep save_buffer_ptr; /* current location in save_buffer */
+ png_bytep save_buffer; /* buffer for previously read data */
+ png_bytep current_buffer_ptr; /* current location in current_buffer */
+ png_bytep current_buffer; /* buffer for recently used data */
+ png_uint_32 push_length; /* size of current input chunk */
+ png_uint_32 skip_length; /* bytes to skip in input data */
+ png_size_t save_buffer_size; /* amount of data now in save_buffer */
+ png_size_t save_buffer_max; /* total size of save_buffer */
+ png_size_t buffer_size; /* total amount of available input data */
+ png_size_t current_buffer_size; /* amount of data now in current_buffer */
+ int process_mode; /* what push library is currently doing */
+ int cur_palette; /* current push library palette index */
+
+#endif /* PROGRESSIVE_READ */
+
+#if defined(__TURBOC__) && !defined(_Windows) && !defined(__FLAT__)
+/* For the Borland special 64K segment handler */
+ png_bytepp offset_table_ptr;
+ png_bytep offset_table;
+ png_uint_16 offset_table_number;
+ png_uint_16 offset_table_count;
+ png_uint_16 offset_table_count_free;
+#endif
+
+#ifdef PNG_READ_QUANTIZE_SUPPORTED
+ png_bytep palette_lookup; /* lookup table for quantizing */
+ png_bytep quantize_index; /* index translation for palette files */
+#endif
+
+#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
+ png_byte heuristic_method; /* heuristic for row filter selection */
+ png_byte num_prev_filters; /* number of weights for previous rows */
+ png_bytep prev_filters; /* filter type(s) of previous row(s) */
+ png_uint_16p filter_weights; /* weight(s) for previous line(s) */
+ png_uint_16p inv_filter_weights; /* 1/weight(s) for previous line(s) */
+ png_uint_16p filter_costs; /* relative filter calculation cost */
+ png_uint_16p inv_filter_costs; /* 1/relative filter calculation cost */
+#endif
+
+ /* Options */
+#ifdef PNG_SET_OPTION_SUPPORTED
+ png_byte options; /* On/off state (up to 4 options) */
+#endif
+
+#if PNG_LIBPNG_VER < 10700
+/* To do: remove this from libpng-1.7 */
+#ifdef PNG_TIME_RFC1123_SUPPORTED
+ char time_buffer[29]; /* String to hold RFC 1123 time text */
+#endif
+#endif
+
+/* New members added in libpng-1.0.6 */
+
+ png_uint_32 free_me; /* flags items libpng is responsible for freeing */
+
+#ifdef PNG_USER_CHUNKS_SUPPORTED
+ png_voidp user_chunk_ptr;
+#ifdef PNG_READ_USER_CHUNKS_SUPPORTED
+ png_user_chunk_ptr read_user_chunk_fn; /* user read chunk handler */
+#endif
+#endif
+
+#ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
+ int unknown_default; /* As PNG_HANDLE_* */
+ unsigned int num_chunk_list; /* Number of entries in the list */
+ png_bytep chunk_list; /* List of png_byte[5]; the textual chunk name
+ * followed by a PNG_HANDLE_* byte */
+#endif
+
+/* New members added in libpng-1.0.3 */
+#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
+ png_byte rgb_to_gray_status;
+ /* Added in libpng 1.5.5 to record setting of coefficients: */
+ png_byte rgb_to_gray_coefficients_set;
+ /* These were changed from png_byte in libpng-1.0.6 */
+ png_uint_16 rgb_to_gray_red_coeff;
+ png_uint_16 rgb_to_gray_green_coeff;
+ /* deleted in 1.5.5: rgb_to_gray_blue_coeff; */
+#endif
+
+/* New member added in libpng-1.0.4 (renamed in 1.0.9) */
+#if defined(PNG_MNG_FEATURES_SUPPORTED)
+/* Changed from png_byte to png_uint_32 at version 1.2.0 */
+ png_uint_32 mng_features_permitted;
+#endif
+
+/* New member added in libpng-1.0.9, ifdef'ed out in 1.0.12, enabled in 1.2.0 */
+#ifdef PNG_MNG_FEATURES_SUPPORTED
+ png_byte filter_type;
+#endif
+
+/* New members added in libpng-1.2.0 */
+
+/* New members added in libpng-1.0.2 but first enabled by default in 1.2.0 */
+#ifdef PNG_USER_MEM_SUPPORTED
+ png_voidp mem_ptr; /* user supplied struct for mem functions */
+ png_malloc_ptr malloc_fn; /* function for allocating memory */
+ png_free_ptr free_fn; /* function for freeing memory */
+#endif
+
+/* New member added in libpng-1.0.13 and 1.2.0 */
+ png_bytep big_row_buf; /* buffer to save current (unfiltered) row */
+
+#ifdef PNG_READ_QUANTIZE_SUPPORTED
+/* The following three members were added at version 1.0.14 and 1.2.4 */
+ png_bytep quantize_sort; /* working sort array */
+ png_bytep index_to_palette; /* where the original index currently is
+ in the palette */
+ png_bytep palette_to_index; /* which original index points to this
+ palette color */
+#endif
+
+/* New members added in libpng-1.0.16 and 1.2.6 */
+ png_byte compression_type;
+
+#ifdef PNG_USER_LIMITS_SUPPORTED
+ png_uint_32 user_width_max;
+ png_uint_32 user_height_max;
+
+ /* Added in libpng-1.4.0: Total number of sPLT, text, and unknown
+ * chunks that can be stored (0 means unlimited).
+ */
+ png_uint_32 user_chunk_cache_max;
+
+ /* Total memory that a zTXt, sPLT, iTXt, iCCP, or unknown chunk
+ * can occupy when decompressed. 0 means unlimited.
+ */
+ png_alloc_size_t user_chunk_malloc_max;
+#endif
+
+/* New member added in libpng-1.0.25 and 1.2.17 */
+#ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED
+ /* Temporary storage for unknown chunk that the library doesn't recognize,
+ * used while reading the chunk.
+ */
+ png_unknown_chunk unknown_chunk;
+#endif
+
+/* New member added in libpng-1.2.26 */
+ png_size_t old_big_row_buf_size;
+
+#ifdef PNG_READ_SUPPORTED
+/* New member added in libpng-1.2.30 */
+ png_bytep read_buffer; /* buffer for reading chunk data */
+ png_alloc_size_t read_buffer_size; /* current size of the buffer */
+#endif
+#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
+ uInt IDAT_read_size; /* limit on read buffer size for IDAT */
+#endif
+
+#ifdef PNG_IO_STATE_SUPPORTED
+/* New member added in libpng-1.4.0 */
+ png_uint_32 io_state;
+#endif
+
+/* New member added in libpng-1.5.6 */
+ png_bytep big_prev_row;
+
+/* New member added in libpng-1.5.7 */
+ void (*read_filter[PNG_FILTER_VALUE_LAST-1])(png_row_infop row_info,
+ png_bytep row, png_const_bytep prev_row);
+
+#ifdef PNG_READ_SUPPORTED
+#if defined(PNG_COLORSPACE_SUPPORTED) || defined(PNG_GAMMA_SUPPORTED)
+ png_colorspace colorspace;
+#endif
+#endif
+};
+#endif /* PNGSTRUCT_H */
--- /dev/null
+
+/* pngtrans.c - transforms the data in a row (used by both readers and writers)
+ *
+ * Last changed in libpng 1.6.17 [March 26, 2015]
+ * Copyright (c) 1998-2015 Glenn Randers-Pehrson
+ * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
+ * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ */
+
+#include "pngpriv.h"
+
+#if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
+
+#if defined(PNG_READ_BGR_SUPPORTED) || defined(PNG_WRITE_BGR_SUPPORTED)
+/* Turn on BGR-to-RGB mapping */
+void PNGAPI
+png_set_bgr(png_structrp png_ptr)
+{
+ png_debug(1, "in png_set_bgr");
+
+ if (png_ptr == NULL)
+ return;
+
+ png_ptr->transformations |= PNG_BGR;
+}
+#endif
+
+#if defined(PNG_READ_SWAP_SUPPORTED) || defined(PNG_WRITE_SWAP_SUPPORTED)
+/* Turn on 16 bit byte swapping */
+void PNGAPI
+png_set_swap(png_structrp png_ptr)
+{
+ png_debug(1, "in png_set_swap");
+
+ if (png_ptr == NULL)
+ return;
+
+ if (png_ptr->bit_depth == 16)
+ png_ptr->transformations |= PNG_SWAP_BYTES;
+}
+#endif
+
+#if defined(PNG_READ_PACK_SUPPORTED) || defined(PNG_WRITE_PACK_SUPPORTED)
+/* Turn on pixel packing */
+void PNGAPI
+png_set_packing(png_structrp png_ptr)
+{
+ png_debug(1, "in png_set_packing");
+
+ if (png_ptr == NULL)
+ return;
+
+ if (png_ptr->bit_depth < 8)
+ {
+ png_ptr->transformations |= PNG_PACK;
+# ifdef PNG_WRITE_SUPPORTED
+ png_ptr->usr_bit_depth = 8;
+# endif
+ }
+}
+#endif
+
+#if defined(PNG_READ_PACKSWAP_SUPPORTED)||defined(PNG_WRITE_PACKSWAP_SUPPORTED)
+/* Turn on packed pixel swapping */
+void PNGAPI
+png_set_packswap(png_structrp png_ptr)
+{
+ png_debug(1, "in png_set_packswap");
+
+ if (png_ptr == NULL)
+ return;
+
+ if (png_ptr->bit_depth < 8)
+ png_ptr->transformations |= PNG_PACKSWAP;
+}
+#endif
+
+#if defined(PNG_READ_SHIFT_SUPPORTED) || defined(PNG_WRITE_SHIFT_SUPPORTED)
+void PNGAPI
+png_set_shift(png_structrp png_ptr, png_const_color_8p true_bits)
+{
+ png_debug(1, "in png_set_shift");
+
+ if (png_ptr == NULL)
+ return;
+
+ png_ptr->transformations |= PNG_SHIFT;
+ png_ptr->shift = *true_bits;
+}
+#endif
+
+#if defined(PNG_READ_INTERLACING_SUPPORTED) || \
+ defined(PNG_WRITE_INTERLACING_SUPPORTED)
+int PNGAPI
+png_set_interlace_handling(png_structrp png_ptr)
+{
+ png_debug(1, "in png_set_interlace handling");
+
+ if (png_ptr != 0 && png_ptr->interlaced != 0)
+ {
+ png_ptr->transformations |= PNG_INTERLACE;
+ return (7);
+ }
+
+ return (1);
+}
+#endif
+
+#if defined(PNG_READ_FILLER_SUPPORTED) || defined(PNG_WRITE_FILLER_SUPPORTED)
+/* Add a filler byte on read, or remove a filler or alpha byte on write.
+ * The filler type has changed in v0.95 to allow future 2-byte fillers
+ * for 48-bit input data, as well as to avoid problems with some compilers
+ * that don't like bytes as parameters.
+ */
+void PNGAPI
+png_set_filler(png_structrp png_ptr, png_uint_32 filler, int filler_loc)
+{
+ png_debug(1, "in png_set_filler");
+
+ if (png_ptr == NULL)
+ return;
+
+ /* In libpng 1.6 it is possible to determine whether this is a read or write
+ * operation and therefore to do more checking here for a valid call.
+ */
+ if ((png_ptr->mode & PNG_IS_READ_STRUCT) != 0)
+ {
+# ifdef PNG_READ_FILLER_SUPPORTED
+ /* On read png_set_filler is always valid, regardless of the base PNG
+ * format, because other transformations can give a format where the
+ * filler code can execute (basically an 8 or 16-bit component RGB or G
+ * format.)
+ *
+ * NOTE: usr_channels is not used by the read code! (This has led to
+ * confusion in the past.) The filler is only used in the read code.
+ */
+ png_ptr->filler = (png_uint_16)filler;
+# else
+ png_app_error(png_ptr, "png_set_filler not supported on read");
+ PNG_UNUSED(filler) /* not used in the write case */
+ return;
+# endif
+ }
+
+ else /* write */
+ {
+# ifdef PNG_WRITE_FILLER_SUPPORTED
+ /* On write the usr_channels parameter must be set correctly at the
+ * start to record the number of channels in the app-supplied data.
+ */
+ switch (png_ptr->color_type)
+ {
+ case PNG_COLOR_TYPE_RGB:
+ png_ptr->usr_channels = 4;
+ break;
+
+ case PNG_COLOR_TYPE_GRAY:
+ if (png_ptr->bit_depth >= 8)
+ {
+ png_ptr->usr_channels = 2;
+ break;
+ }
+
+ else
+ {
+ /* There simply isn't any code in libpng to strip out bits
+ * from bytes when the components are less than a byte in
+ * size!
+ */
+ png_app_error(png_ptr,
+ "png_set_filler is invalid for low bit depth gray output");
+ return;
+ }
+
+ default:
+ png_app_error(png_ptr,
+ "png_set_filler: inappropriate color type");
+ return;
+ }
+# else
+ png_app_error(png_ptr, "png_set_filler not supported on write");
+ return;
+# endif
+ }
+
+ /* Here on success - libpng supports the operation, set the transformation
+ * and the flag to say where the filler channel is.
+ */
+ png_ptr->transformations |= PNG_FILLER;
+
+ if (filler_loc == PNG_FILLER_AFTER)
+ png_ptr->flags |= PNG_FLAG_FILLER_AFTER;
+
+ else
+ png_ptr->flags &= ~PNG_FLAG_FILLER_AFTER;
+}
+
+/* Added to libpng-1.2.7 */
+void PNGAPI
+png_set_add_alpha(png_structrp png_ptr, png_uint_32 filler, int filler_loc)
+{
+ png_debug(1, "in png_set_add_alpha");
+
+ if (png_ptr == NULL)
+ return;
+
+ png_set_filler(png_ptr, filler, filler_loc);
+ /* The above may fail to do anything. */
+ if ((png_ptr->transformations & PNG_FILLER) != 0)
+ png_ptr->transformations |= PNG_ADD_ALPHA;
+}
+
+#endif
+
+#if defined(PNG_READ_SWAP_ALPHA_SUPPORTED) || \
+ defined(PNG_WRITE_SWAP_ALPHA_SUPPORTED)
+void PNGAPI
+png_set_swap_alpha(png_structrp png_ptr)
+{
+ png_debug(1, "in png_set_swap_alpha");
+
+ if (png_ptr == NULL)
+ return;
+
+ png_ptr->transformations |= PNG_SWAP_ALPHA;
+}
+#endif
+
+#if defined(PNG_READ_INVERT_ALPHA_SUPPORTED) || \
+ defined(PNG_WRITE_INVERT_ALPHA_SUPPORTED)
+void PNGAPI
+png_set_invert_alpha(png_structrp png_ptr)
+{
+ png_debug(1, "in png_set_invert_alpha");
+
+ if (png_ptr == NULL)
+ return;
+
+ png_ptr->transformations |= PNG_INVERT_ALPHA;
+}
+#endif
+
+#if defined(PNG_READ_INVERT_SUPPORTED) || defined(PNG_WRITE_INVERT_SUPPORTED)
+void PNGAPI
+png_set_invert_mono(png_structrp png_ptr)
+{
+ png_debug(1, "in png_set_invert_mono");
+
+ if (png_ptr == NULL)
+ return;
+
+ png_ptr->transformations |= PNG_INVERT_MONO;
+}
+
+/* Invert monochrome grayscale data */
+void /* PRIVATE */
+png_do_invert(png_row_infop row_info, png_bytep row)
+{
+ png_debug(1, "in png_do_invert");
+
+ /* This test removed from libpng version 1.0.13 and 1.2.0:
+ * if (row_info->bit_depth == 1 &&
+ */
+ if (row_info->color_type == PNG_COLOR_TYPE_GRAY)
+ {
+ png_bytep rp = row;
+ png_size_t i;
+ png_size_t istop = row_info->rowbytes;
+
+ for (i = 0; i < istop; i++)
+ {
+ *rp = (png_byte)(~(*rp));
+ rp++;
+ }
+ }
+
+ else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA &&
+ row_info->bit_depth == 8)
+ {
+ png_bytep rp = row;
+ png_size_t i;
+ png_size_t istop = row_info->rowbytes;
+
+ for (i = 0; i < istop; i += 2)
+ {
+ *rp = (png_byte)(~(*rp));
+ rp += 2;
+ }
+ }
+
+#ifdef PNG_16BIT_SUPPORTED
+ else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA &&
+ row_info->bit_depth == 16)
+ {
+ png_bytep rp = row;
+ png_size_t i;
+ png_size_t istop = row_info->rowbytes;
+
+ for (i = 0; i < istop; i += 4)
+ {
+ *rp = (png_byte)(~(*rp));
+ *(rp + 1) = (png_byte)(~(*(rp + 1)));
+ rp += 4;
+ }
+ }
+#endif
+}
+#endif
+
+#ifdef PNG_16BIT_SUPPORTED
+#if defined(PNG_READ_SWAP_SUPPORTED) || defined(PNG_WRITE_SWAP_SUPPORTED)
+/* Swaps byte order on 16 bit depth images */
+void /* PRIVATE */
+png_do_swap(png_row_infop row_info, png_bytep row)
+{
+ png_debug(1, "in png_do_swap");
+
+ if (row_info->bit_depth == 16)
+ {
+ png_bytep rp = row;
+ png_uint_32 i;
+ png_uint_32 istop= row_info->width * row_info->channels;
+
+ for (i = 0; i < istop; i++, rp += 2)
+ {
+#ifdef PNG_BUILTIN_BSWAP16_SUPPORTED
+ /* Feature added to libpng-1.6.11 for testing purposes, not
+ * enabled by default.
+ */
+ *(png_uint_16*)rp = __builtin_bswap16(*(png_uint_16*)rp);
+#else
+ png_byte t = *rp;
+ *rp = *(rp + 1);
+ *(rp + 1) = t;
+#endif
+ }
+ }
+}
+#endif
+#endif
+
+#if defined(PNG_READ_PACKSWAP_SUPPORTED)||defined(PNG_WRITE_PACKSWAP_SUPPORTED)
+static PNG_CONST png_byte onebppswaptable[256] = {
+ 0x00, 0x80, 0x40, 0xC0, 0x20, 0xA0, 0x60, 0xE0,
+ 0x10, 0x90, 0x50, 0xD0, 0x30, 0xB0, 0x70, 0xF0,
+ 0x08, 0x88, 0x48, 0xC8, 0x28, 0xA8, 0x68, 0xE8,
+ 0x18, 0x98, 0x58, 0xD8, 0x38, 0xB8, 0x78, 0xF8,
+ 0x04, 0x84, 0x44, 0xC4, 0x24, 0xA4, 0x64, 0xE4,
+ 0x14, 0x94, 0x54, 0xD4, 0x34, 0xB4, 0x74, 0xF4,
+ 0x0C, 0x8C, 0x4C, 0xCC, 0x2C, 0xAC, 0x6C, 0xEC,
+ 0x1C, 0x9C, 0x5C, 0xDC, 0x3C, 0xBC, 0x7C, 0xFC,
+ 0x02, 0x82, 0x42, 0xC2, 0x22, 0xA2, 0x62, 0xE2,
+ 0x12, 0x92, 0x52, 0xD2, 0x32, 0xB2, 0x72, 0xF2,
+ 0x0A, 0x8A, 0x4A, 0xCA, 0x2A, 0xAA, 0x6A, 0xEA,
+ 0x1A, 0x9A, 0x5A, 0xDA, 0x3A, 0xBA, 0x7A, 0xFA,
+ 0x06, 0x86, 0x46, 0xC6, 0x26, 0xA6, 0x66, 0xE6,
+ 0x16, 0x96, 0x56, 0xD6, 0x36, 0xB6, 0x76, 0xF6,
+ 0x0E, 0x8E, 0x4E, 0xCE, 0x2E, 0xAE, 0x6E, 0xEE,
+ 0x1E, 0x9E, 0x5E, 0xDE, 0x3E, 0xBE, 0x7E, 0xFE,
+ 0x01, 0x81, 0x41, 0xC1, 0x21, 0xA1, 0x61, 0xE1,
+ 0x11, 0x91, 0x51, 0xD1, 0x31, 0xB1, 0x71, 0xF1,
+ 0x09, 0x89, 0x49, 0xC9, 0x29, 0xA9, 0x69, 0xE9,
+ 0x19, 0x99, 0x59, 0xD9, 0x39, 0xB9, 0x79, 0xF9,
+ 0x05, 0x85, 0x45, 0xC5, 0x25, 0xA5, 0x65, 0xE5,
+ 0x15, 0x95, 0x55, 0xD5, 0x35, 0xB5, 0x75, 0xF5,
+ 0x0D, 0x8D, 0x4D, 0xCD, 0x2D, 0xAD, 0x6D, 0xED,
+ 0x1D, 0x9D, 0x5D, 0xDD, 0x3D, 0xBD, 0x7D, 0xFD,
+ 0x03, 0x83, 0x43, 0xC3, 0x23, 0xA3, 0x63, 0xE3,
+ 0x13, 0x93, 0x53, 0xD3, 0x33, 0xB3, 0x73, 0xF3,
+ 0x0B, 0x8B, 0x4B, 0xCB, 0x2B, 0xAB, 0x6B, 0xEB,
+ 0x1B, 0x9B, 0x5B, 0xDB, 0x3B, 0xBB, 0x7B, 0xFB,
+ 0x07, 0x87, 0x47, 0xC7, 0x27, 0xA7, 0x67, 0xE7,
+ 0x17, 0x97, 0x57, 0xD7, 0x37, 0xB7, 0x77, 0xF7,
+ 0x0F, 0x8F, 0x4F, 0xCF, 0x2F, 0xAF, 0x6F, 0xEF,
+ 0x1F, 0x9F, 0x5F, 0xDF, 0x3F, 0xBF, 0x7F, 0xFF
+};
+
+static PNG_CONST png_byte twobppswaptable[256] = {
+ 0x00, 0x40, 0x80, 0xC0, 0x10, 0x50, 0x90, 0xD0,
+ 0x20, 0x60, 0xA0, 0xE0, 0x30, 0x70, 0xB0, 0xF0,
+ 0x04, 0x44, 0x84, 0xC4, 0x14, 0x54, 0x94, 0xD4,
+ 0x24, 0x64, 0xA4, 0xE4, 0x34, 0x74, 0xB4, 0xF4,
+ 0x08, 0x48, 0x88, 0xC8, 0x18, 0x58, 0x98, 0xD8,
+ 0x28, 0x68, 0xA8, 0xE8, 0x38, 0x78, 0xB8, 0xF8,
+ 0x0C, 0x4C, 0x8C, 0xCC, 0x1C, 0x5C, 0x9C, 0xDC,
+ 0x2C, 0x6C, 0xAC, 0xEC, 0x3C, 0x7C, 0xBC, 0xFC,
+ 0x01, 0x41, 0x81, 0xC1, 0x11, 0x51, 0x91, 0xD1,
+ 0x21, 0x61, 0xA1, 0xE1, 0x31, 0x71, 0xB1, 0xF1,
+ 0x05, 0x45, 0x85, 0xC5, 0x15, 0x55, 0x95, 0xD5,
+ 0x25, 0x65, 0xA5, 0xE5, 0x35, 0x75, 0xB5, 0xF5,
+ 0x09, 0x49, 0x89, 0xC9, 0x19, 0x59, 0x99, 0xD9,
+ 0x29, 0x69, 0xA9, 0xE9, 0x39, 0x79, 0xB9, 0xF9,
+ 0x0D, 0x4D, 0x8D, 0xCD, 0x1D, 0x5D, 0x9D, 0xDD,
+ 0x2D, 0x6D, 0xAD, 0xED, 0x3D, 0x7D, 0xBD, 0xFD,
+ 0x02, 0x42, 0x82, 0xC2, 0x12, 0x52, 0x92, 0xD2,
+ 0x22, 0x62, 0xA2, 0xE2, 0x32, 0x72, 0xB2, 0xF2,
+ 0x06, 0x46, 0x86, 0xC6, 0x16, 0x56, 0x96, 0xD6,
+ 0x26, 0x66, 0xA6, 0xE6, 0x36, 0x76, 0xB6, 0xF6,
+ 0x0A, 0x4A, 0x8A, 0xCA, 0x1A, 0x5A, 0x9A, 0xDA,
+ 0x2A, 0x6A, 0xAA, 0xEA, 0x3A, 0x7A, 0xBA, 0xFA,
+ 0x0E, 0x4E, 0x8E, 0xCE, 0x1E, 0x5E, 0x9E, 0xDE,
+ 0x2E, 0x6E, 0xAE, 0xEE, 0x3E, 0x7E, 0xBE, 0xFE,
+ 0x03, 0x43, 0x83, 0xC3, 0x13, 0x53, 0x93, 0xD3,
+ 0x23, 0x63, 0xA3, 0xE3, 0x33, 0x73, 0xB3, 0xF3,
+ 0x07, 0x47, 0x87, 0xC7, 0x17, 0x57, 0x97, 0xD7,
+ 0x27, 0x67, 0xA7, 0xE7, 0x37, 0x77, 0xB7, 0xF7,
+ 0x0B, 0x4B, 0x8B, 0xCB, 0x1B, 0x5B, 0x9B, 0xDB,
+ 0x2B, 0x6B, 0xAB, 0xEB, 0x3B, 0x7B, 0xBB, 0xFB,
+ 0x0F, 0x4F, 0x8F, 0xCF, 0x1F, 0x5F, 0x9F, 0xDF,
+ 0x2F, 0x6F, 0xAF, 0xEF, 0x3F, 0x7F, 0xBF, 0xFF
+};
+
+static PNG_CONST png_byte fourbppswaptable[256] = {
+ 0x00, 0x10, 0x20, 0x30, 0x40, 0x50, 0x60, 0x70,
+ 0x80, 0x90, 0xA0, 0xB0, 0xC0, 0xD0, 0xE0, 0xF0,
+ 0x01, 0x11, 0x21, 0x31, 0x41, 0x51, 0x61, 0x71,
+ 0x81, 0x91, 0xA1, 0xB1, 0xC1, 0xD1, 0xE1, 0xF1,
+ 0x02, 0x12, 0x22, 0x32, 0x42, 0x52, 0x62, 0x72,
+ 0x82, 0x92, 0xA2, 0xB2, 0xC2, 0xD2, 0xE2, 0xF2,
+ 0x03, 0x13, 0x23, 0x33, 0x43, 0x53, 0x63, 0x73,
+ 0x83, 0x93, 0xA3, 0xB3, 0xC3, 0xD3, 0xE3, 0xF3,
+ 0x04, 0x14, 0x24, 0x34, 0x44, 0x54, 0x64, 0x74,
+ 0x84, 0x94, 0xA4, 0xB4, 0xC4, 0xD4, 0xE4, 0xF4,
+ 0x05, 0x15, 0x25, 0x35, 0x45, 0x55, 0x65, 0x75,
+ 0x85, 0x95, 0xA5, 0xB5, 0xC5, 0xD5, 0xE5, 0xF5,
+ 0x06, 0x16, 0x26, 0x36, 0x46, 0x56, 0x66, 0x76,
+ 0x86, 0x96, 0xA6, 0xB6, 0xC6, 0xD6, 0xE6, 0xF6,
+ 0x07, 0x17, 0x27, 0x37, 0x47, 0x57, 0x67, 0x77,
+ 0x87, 0x97, 0xA7, 0xB7, 0xC7, 0xD7, 0xE7, 0xF7,
+ 0x08, 0x18, 0x28, 0x38, 0x48, 0x58, 0x68, 0x78,
+ 0x88, 0x98, 0xA8, 0xB8, 0xC8, 0xD8, 0xE8, 0xF8,
+ 0x09, 0x19, 0x29, 0x39, 0x49, 0x59, 0x69, 0x79,
+ 0x89, 0x99, 0xA9, 0xB9, 0xC9, 0xD9, 0xE9, 0xF9,
+ 0x0A, 0x1A, 0x2A, 0x3A, 0x4A, 0x5A, 0x6A, 0x7A,
+ 0x8A, 0x9A, 0xAA, 0xBA, 0xCA, 0xDA, 0xEA, 0xFA,
+ 0x0B, 0x1B, 0x2B, 0x3B, 0x4B, 0x5B, 0x6B, 0x7B,
+ 0x8B, 0x9B, 0xAB, 0xBB, 0xCB, 0xDB, 0xEB, 0xFB,
+ 0x0C, 0x1C, 0x2C, 0x3C, 0x4C, 0x5C, 0x6C, 0x7C,
+ 0x8C, 0x9C, 0xAC, 0xBC, 0xCC, 0xDC, 0xEC, 0xFC,
+ 0x0D, 0x1D, 0x2D, 0x3D, 0x4D, 0x5D, 0x6D, 0x7D,
+ 0x8D, 0x9D, 0xAD, 0xBD, 0xCD, 0xDD, 0xED, 0xFD,
+ 0x0E, 0x1E, 0x2E, 0x3E, 0x4E, 0x5E, 0x6E, 0x7E,
+ 0x8E, 0x9E, 0xAE, 0xBE, 0xCE, 0xDE, 0xEE, 0xFE,
+ 0x0F, 0x1F, 0x2F, 0x3F, 0x4F, 0x5F, 0x6F, 0x7F,
+ 0x8F, 0x9F, 0xAF, 0xBF, 0xCF, 0xDF, 0xEF, 0xFF
+};
+
+/* Swaps pixel packing order within bytes */
+void /* PRIVATE */
+png_do_packswap(png_row_infop row_info, png_bytep row)
+{
+ png_debug(1, "in png_do_packswap");
+
+ if (row_info->bit_depth < 8)
+ {
+ png_bytep rp;
+ png_const_bytep end, table;
+
+ end = row + row_info->rowbytes;
+
+ if (row_info->bit_depth == 1)
+ table = onebppswaptable;
+
+ else if (row_info->bit_depth == 2)
+ table = twobppswaptable;
+
+ else if (row_info->bit_depth == 4)
+ table = fourbppswaptable;
+
+ else
+ return;
+
+ for (rp = row; rp < end; rp++)
+ *rp = table[*rp];
+ }
+}
+#endif /* PACKSWAP || WRITE_PACKSWAP */
+
+#if defined(PNG_WRITE_FILLER_SUPPORTED) || \
+ defined(PNG_READ_STRIP_ALPHA_SUPPORTED)
+/* Remove a channel - this used to be 'png_do_strip_filler' but it used a
+ * somewhat weird combination of flags to determine what to do. All the calls
+ * to png_do_strip_filler are changed in 1.5.2 to call this instead with the
+ * correct arguments.
+ *
+ * The routine isn't general - the channel must be the channel at the start or
+ * end (not in the middle) of each pixel.
+ */
+void /* PRIVATE */
+png_do_strip_channel(png_row_infop row_info, png_bytep row, int at_start)
+{
+ png_bytep sp = row; /* source pointer */
+ png_bytep dp = row; /* destination pointer */
+ png_bytep ep = row + row_info->rowbytes; /* One beyond end of row */
+
+ /* At the start sp will point to the first byte to copy and dp to where
+ * it is copied to. ep always points just beyond the end of the row, so
+ * the loop simply copies (channels-1) channels until sp reaches ep.
+ *
+ * at_start: 0 -- convert AG, XG, ARGB, XRGB, AAGG, XXGG, etc.
+ * nonzero -- convert GA, GX, RGBA, RGBX, GGAA, RRGGBBXX, etc.
+ */
+
+ /* GA, GX, XG cases */
+ if (row_info->channels == 2)
+ {
+ if (row_info->bit_depth == 8)
+ {
+ if (at_start != 0) /* Skip initial filler */
+ ++sp;
+ else /* Skip initial channel and, for sp, the filler */
+ sp += 2, ++dp;
+
+ /* For a 1 pixel wide image there is nothing to do */
+ while (sp < ep)
+ *dp++ = *sp, sp += 2;
+
+ row_info->pixel_depth = 8;
+ }
+
+ else if (row_info->bit_depth == 16)
+ {
+ if (at_start != 0) /* Skip initial filler */
+ sp += 2;
+ else /* Skip initial channel and, for sp, the filler */
+ sp += 4, dp += 2;
+
+ while (sp < ep)
+ *dp++ = *sp++, *dp++ = *sp, sp += 3;
+
+ row_info->pixel_depth = 16;
+ }
+
+ else
+ return; /* bad bit depth */
+
+ row_info->channels = 1;
+
+ /* Finally fix the color type if it records an alpha channel */
+ if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
+ row_info->color_type = PNG_COLOR_TYPE_GRAY;
+ }
+
+ /* RGBA, RGBX, XRGB cases */
+ else if (row_info->channels == 4)
+ {
+ if (row_info->bit_depth == 8)
+ {
+ if (at_start != 0) /* Skip initial filler */
+ ++sp;
+ else /* Skip initial channels and, for sp, the filler */
+ sp += 4, dp += 3;
+
+ /* Note that the loop adds 3 to dp and 4 to sp each time. */
+ while (sp < ep)
+ *dp++ = *sp++, *dp++ = *sp++, *dp++ = *sp, sp += 2;
+
+ row_info->pixel_depth = 24;
+ }
+
+ else if (row_info->bit_depth == 16)
+ {
+ if (at_start != 0) /* Skip initial filler */
+ sp += 2;
+ else /* Skip initial channels and, for sp, the filler */
+ sp += 8, dp += 6;
+
+ while (sp < ep)
+ {
+ /* Copy 6 bytes, skip 2 */
+ *dp++ = *sp++, *dp++ = *sp++;
+ *dp++ = *sp++, *dp++ = *sp++;
+ *dp++ = *sp++, *dp++ = *sp, sp += 3;
+ }
+
+ row_info->pixel_depth = 48;
+ }
+
+ else
+ return; /* bad bit depth */
+
+ row_info->channels = 3;
+
+ /* Finally fix the color type if it records an alpha channel */
+ if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+ row_info->color_type = PNG_COLOR_TYPE_RGB;
+ }
+
+ else
+ return; /* The filler channel has gone already */
+
+ /* Fix the rowbytes value. */
+ row_info->rowbytes = dp-row;
+}
+#endif
+
+#if defined(PNG_READ_BGR_SUPPORTED) || defined(PNG_WRITE_BGR_SUPPORTED)
+/* Swaps red and blue bytes within a pixel */
+void /* PRIVATE */
+png_do_bgr(png_row_infop row_info, png_bytep row)
+{
+ png_debug(1, "in png_do_bgr");
+
+ if ((row_info->color_type & PNG_COLOR_MASK_COLOR) != 0)
+ {
+ png_uint_32 row_width = row_info->width;
+ if (row_info->bit_depth == 8)
+ {
+ if (row_info->color_type == PNG_COLOR_TYPE_RGB)
+ {
+ png_bytep rp;
+ png_uint_32 i;
+
+ for (i = 0, rp = row; i < row_width; i++, rp += 3)
+ {
+ png_byte save = *rp;
+ *rp = *(rp + 2);
+ *(rp + 2) = save;
+ }
+ }
+
+ else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+ {
+ png_bytep rp;
+ png_uint_32 i;
+
+ for (i = 0, rp = row; i < row_width; i++, rp += 4)
+ {
+ png_byte save = *rp;
+ *rp = *(rp + 2);
+ *(rp + 2) = save;
+ }
+ }
+ }
+
+#ifdef PNG_16BIT_SUPPORTED
+ else if (row_info->bit_depth == 16)
+ {
+ if (row_info->color_type == PNG_COLOR_TYPE_RGB)
+ {
+ png_bytep rp;
+ png_uint_32 i;
+
+ for (i = 0, rp = row; i < row_width; i++, rp += 6)
+ {
+ png_byte save = *rp;
+ *rp = *(rp + 4);
+ *(rp + 4) = save;
+ save = *(rp + 1);
+ *(rp + 1) = *(rp + 5);
+ *(rp + 5) = save;
+ }
+ }
+
+ else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+ {
+ png_bytep rp;
+ png_uint_32 i;
+
+ for (i = 0, rp = row; i < row_width; i++, rp += 8)
+ {
+ png_byte save = *rp;
+ *rp = *(rp + 4);
+ *(rp + 4) = save;
+ save = *(rp + 1);
+ *(rp + 1) = *(rp + 5);
+ *(rp + 5) = save;
+ }
+ }
+ }
+#endif
+ }
+}
+#endif /* READ_BGR || WRITE_BGR */
+
+#if defined(PNG_READ_CHECK_FOR_INVALID_INDEX_SUPPORTED) || \
+ defined(PNG_WRITE_CHECK_FOR_INVALID_INDEX_SUPPORTED)
+/* Added at libpng-1.5.10 */
+void /* PRIVATE */
+png_do_check_palette_indexes(png_structrp png_ptr, png_row_infop row_info)
+{
+ if (png_ptr->num_palette < (1 << row_info->bit_depth) &&
+ png_ptr->num_palette > 0) /* num_palette can be 0 in MNG files */
+ {
+ /* Calculations moved outside switch in an attempt to stop different
+ * compiler warnings. 'padding' is in *bits* within the last byte, it is
+ * an 'int' because pixel_depth becomes an 'int' in the expression below,
+ * and this calculation is used because it avoids warnings that other
+ * forms produced on either GCC or MSVC.
+ */
+ int padding = (-row_info->pixel_depth * row_info->width) & 7;
+ png_bytep rp = png_ptr->row_buf + row_info->rowbytes;
+
+ switch (row_info->bit_depth)
+ {
+ case 1:
+ {
+ /* in this case, all bytes must be 0 so we don't need
+ * to unpack the pixels except for the rightmost one.
+ */
+ for (; rp > png_ptr->row_buf; rp--)
+ {
+ if (*rp >> padding != 0)
+ png_ptr->num_palette_max = 1;
+ padding = 0;
+ }
+
+ break;
+ }
+
+ case 2:
+ {
+ for (; rp > png_ptr->row_buf; rp--)
+ {
+ int i = ((*rp >> padding) & 0x03);
+
+ if (i > png_ptr->num_palette_max)
+ png_ptr->num_palette_max = i;
+
+ i = (((*rp >> padding) >> 2) & 0x03);
+
+ if (i > png_ptr->num_palette_max)
+ png_ptr->num_palette_max = i;
+
+ i = (((*rp >> padding) >> 4) & 0x03);
+
+ if (i > png_ptr->num_palette_max)
+ png_ptr->num_palette_max = i;
+
+ i = (((*rp >> padding) >> 6) & 0x03);
+
+ if (i > png_ptr->num_palette_max)
+ png_ptr->num_palette_max = i;
+
+ padding = 0;
+ }
+
+ break;
+ }
+
+ case 4:
+ {
+ for (; rp > png_ptr->row_buf; rp--)
+ {
+ int i = ((*rp >> padding) & 0x0f);
+
+ if (i > png_ptr->num_palette_max)
+ png_ptr->num_palette_max = i;
+
+ i = (((*rp >> padding) >> 4) & 0x0f);
+
+ if (i > png_ptr->num_palette_max)
+ png_ptr->num_palette_max = i;
+
+ padding = 0;
+ }
+
+ break;
+ }
+
+ case 8:
+ {
+ for (; rp > png_ptr->row_buf; rp--)
+ {
+ if (*rp > png_ptr->num_palette_max)
+ png_ptr->num_palette_max = (int) *rp;
+ }
+
+ break;
+ }
+
+ default:
+ break;
+ }
+ }
+}
+#endif /* CHECK_FOR_INVALID_INDEX */
+
+#if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) || \
+ defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED)
+#ifdef PNG_USER_TRANSFORM_PTR_SUPPORTED
+void PNGAPI
+png_set_user_transform_info(png_structrp png_ptr, png_voidp
+ user_transform_ptr, int user_transform_depth, int user_transform_channels)
+{
+ png_debug(1, "in png_set_user_transform_info");
+
+ if (png_ptr == NULL)
+ return;
+
+#ifdef PNG_READ_USER_TRANSFORM_SUPPORTED
+ if ((png_ptr->mode & PNG_IS_READ_STRUCT) != 0 &&
+ (png_ptr->flags & PNG_FLAG_ROW_INIT) != 0)
+ {
+ png_app_error(png_ptr,
+ "info change after png_start_read_image or png_read_update_info");
+ return;
+ }
+#endif
+
+ png_ptr->user_transform_ptr = user_transform_ptr;
+ png_ptr->user_transform_depth = (png_byte)user_transform_depth;
+ png_ptr->user_transform_channels = (png_byte)user_transform_channels;
+}
+#endif
+
+/* This function returns a pointer to the user_transform_ptr associated with
+ * the user transform functions. The application should free any memory
+ * associated with this pointer before png_write_destroy and png_read_destroy
+ * are called.
+ */
+#ifdef PNG_USER_TRANSFORM_PTR_SUPPORTED
+png_voidp PNGAPI
+png_get_user_transform_ptr(png_const_structrp png_ptr)
+{
+ if (png_ptr == NULL)
+ return (NULL);
+
+ return png_ptr->user_transform_ptr;
+}
+#endif
+
+#ifdef PNG_USER_TRANSFORM_INFO_SUPPORTED
+png_uint_32 PNGAPI
+png_get_current_row_number(png_const_structrp png_ptr)
+{
+ /* See the comments in png.h - this is the sub-image row when reading an
+ * interlaced image.
+ */
+ if (png_ptr != NULL)
+ return png_ptr->row_number;
+
+ return PNG_UINT_32_MAX; /* help the app not to fail silently */
+}
+
+png_byte PNGAPI
+png_get_current_pass_number(png_const_structrp png_ptr)
+{
+ if (png_ptr != NULL)
+ return png_ptr->pass;
+ return 8; /* invalid */
+}
+#endif /* USER_TRANSFORM_INFO */
+#endif /* READ_USER_TRANSFORM || WRITE_USER_TRANSFORM */
+#endif /* READ || WRITE */
--- /dev/null
+
+/* pngwio.c - functions for data output
+ *
+ * Last changed in libpng 1.6.15 [November 20, 2014]
+ * Copyright (c) 1998-2014 Glenn Randers-Pehrson
+ * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
+ * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ *
+ * This file provides a location for all output. Users who need
+ * special handling are expected to write functions that have the same
+ * arguments as these and perform similar functions, but that possibly
+ * use different output methods. Note that you shouldn't change these
+ * functions, but rather write replacement functions and then change
+ * them at run time with png_set_write_fn(...).
+ */
+
+#include "pngpriv.h"
+
+#ifdef PNG_WRITE_SUPPORTED
+
+/* Write the data to whatever output you are using. The default routine
+ * writes to a file pointer. Note that this routine sometimes gets called
+ * with very small lengths, so you should implement some kind of simple
+ * buffering if you are using unbuffered writes. This should never be asked
+ * to write more than 64K on a 16 bit machine.
+ */
+
+void /* PRIVATE */
+png_write_data(png_structrp png_ptr, png_const_bytep data, png_size_t length)
+{
+ /* NOTE: write_data_fn must not change the buffer! */
+ if (png_ptr->write_data_fn != NULL )
+ (*(png_ptr->write_data_fn))(png_ptr, png_constcast(png_bytep,data),
+ length);
+
+ else
+ png_error(png_ptr, "Call to NULL write function");
+}
+
+#ifdef PNG_STDIO_SUPPORTED
+/* This is the function that does the actual writing of data. If you are
+ * not writing to a standard C stream, you should create a replacement
+ * write_data function and use it at run time with png_set_write_fn(), rather
+ * than changing the library.
+ */
+void PNGCBAPI
+png_default_write_data(png_structp png_ptr, png_bytep data, png_size_t length)
+{
+ png_size_t check;
+
+ if (png_ptr == NULL)
+ return;
+
+ check = fwrite(data, 1, length, (png_FILE_p)(png_ptr->io_ptr));
+
+ if (check != length)
+ png_error(png_ptr, "Write Error");
+}
+#endif
+
+/* This function is called to output any data pending writing (normally
+ * to disk). After png_flush is called, there should be no data pending
+ * writing in any buffers.
+ */
+#ifdef PNG_WRITE_FLUSH_SUPPORTED
+void /* PRIVATE */
+png_flush(png_structrp png_ptr)
+{
+ if (png_ptr->output_flush_fn != NULL)
+ (*(png_ptr->output_flush_fn))(png_ptr);
+}
+
+# ifdef PNG_STDIO_SUPPORTED
+void PNGCBAPI
+png_default_flush(png_structp png_ptr)
+{
+ png_FILE_p io_ptr;
+
+ if (png_ptr == NULL)
+ return;
+
+ io_ptr = png_voidcast(png_FILE_p, (png_ptr->io_ptr));
+ fflush(io_ptr);
+}
+# endif
+#endif
+
+/* This function allows the application to supply new output functions for
+ * libpng if standard C streams aren't being used.
+ *
+ * This function takes as its arguments:
+ * png_ptr - pointer to a png output data structure
+ * io_ptr - pointer to user supplied structure containing info about
+ * the output functions. May be NULL.
+ * write_data_fn - pointer to a new output function that takes as its
+ * arguments a pointer to a png_struct, a pointer to
+ * data to be written, and a 32-bit unsigned int that is
+ * the number of bytes to be written. The new write
+ * function should call png_error(png_ptr, "Error msg")
+ * to exit and output any fatal error messages. May be
+ * NULL, in which case libpng's default function will
+ * be used.
+ * flush_data_fn - pointer to a new flush function that takes as its
+ * arguments a pointer to a png_struct. After a call to
+ * the flush function, there should be no data in any buffers
+ * or pending transmission. If the output method doesn't do
+ * any buffering of output, a function prototype must still be
+ * supplied although it doesn't have to do anything. If
+ * PNG_WRITE_FLUSH_SUPPORTED is not defined at libpng compile
+ * time, output_flush_fn will be ignored, although it must be
+ * supplied for compatibility. May be NULL, in which case
+ * libpng's default function will be used, if
+ * PNG_WRITE_FLUSH_SUPPORTED is defined. This is not
+ * a good idea if io_ptr does not point to a standard
+ * *FILE structure.
+ */
+void PNGAPI
+png_set_write_fn(png_structrp png_ptr, png_voidp io_ptr,
+ png_rw_ptr write_data_fn, png_flush_ptr output_flush_fn)
+{
+ if (png_ptr == NULL)
+ return;
+
+ png_ptr->io_ptr = io_ptr;
+
+#ifdef PNG_STDIO_SUPPORTED
+ if (write_data_fn != NULL)
+ png_ptr->write_data_fn = write_data_fn;
+
+ else
+ png_ptr->write_data_fn = png_default_write_data;
+#else
+ png_ptr->write_data_fn = write_data_fn;
+#endif
+
+#ifdef PNG_WRITE_FLUSH_SUPPORTED
+# ifdef PNG_STDIO_SUPPORTED
+
+ if (output_flush_fn != NULL)
+ png_ptr->output_flush_fn = output_flush_fn;
+
+ else
+ png_ptr->output_flush_fn = png_default_flush;
+
+# else
+ png_ptr->output_flush_fn = output_flush_fn;
+# endif
+#else
+ PNG_UNUSED(output_flush_fn)
+#endif /* WRITE_FLUSH */
+
+#ifdef PNG_READ_SUPPORTED
+ /* It is an error to read while writing a png file */
+ if (png_ptr->read_data_fn != NULL)
+ {
+ png_ptr->read_data_fn = NULL;
+
+ png_warning(png_ptr,
+ "Can't set both read_data_fn and write_data_fn in the"
+ " same structure");
+ }
+#endif
+}
+#endif /* WRITE */
--- /dev/null
+
+/* pngwrite.c - general routines to write a PNG file
+ *
+ * Last changed in libpng 1.6.17 [March 26, 2015]
+ * Copyright (c) 1998-2015 Glenn Randers-Pehrson
+ * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
+ * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ */
+
+#include "pngpriv.h"
+#if defined(PNG_SIMPLIFIED_WRITE_SUPPORTED) && defined(PNG_STDIO_SUPPORTED)
+# include <errno.h>
+#endif
+
+#ifdef PNG_WRITE_SUPPORTED
+
+#ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED
+/* Write out all the unknown chunks for the current given location */
+static void
+write_unknown_chunks(png_structrp png_ptr, png_const_inforp info_ptr,
+ unsigned int where)
+{
+ if (info_ptr->unknown_chunks_num != 0)
+ {
+ png_const_unknown_chunkp up;
+
+ png_debug(5, "writing extra chunks");
+
+ for (up = info_ptr->unknown_chunks;
+ up < info_ptr->unknown_chunks + info_ptr->unknown_chunks_num;
+ ++up)
+ if ((up->location & where) != 0)
+ {
+ /* If per-chunk unknown chunk handling is enabled use it, otherwise
+ * just write the chunks the application has set.
+ */
+#ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
+ int keep = png_handle_as_unknown(png_ptr, up->name);
+
+ /* NOTE: this code is radically different from the read side in the
+ * matter of handling an ancillary unknown chunk. In the read side
+ * the default behavior is to discard it, in the code below the default
+ * behavior is to write it. Critical chunks are, however, only
+ * written if explicitly listed or if the default is set to write all
+ * unknown chunks.
+ *
+ * The default handling is also slightly weird - it is not possible to
+ * stop the writing of all unsafe-to-copy chunks!
+ *
+ * TODO: REVIEW: this would seem to be a bug.
+ */
+ if (keep != PNG_HANDLE_CHUNK_NEVER &&
+ ((up->name[3] & 0x20) /* safe-to-copy overrides everything */ ||
+ keep == PNG_HANDLE_CHUNK_ALWAYS ||
+ (keep == PNG_HANDLE_CHUNK_AS_DEFAULT &&
+ png_ptr->unknown_default == PNG_HANDLE_CHUNK_ALWAYS)))
+#endif
+ {
+ /* TODO: review, what is wrong with a zero length unknown chunk? */
+ if (up->size == 0)
+ png_warning(png_ptr, "Writing zero-length unknown chunk");
+
+ png_write_chunk(png_ptr, up->name, up->data, up->size);
+ }
+ }
+ }
+}
+#endif /* WRITE_UNKNOWN_CHUNKS */
+
+/* Writes all the PNG information. This is the suggested way to use the
+ * library. If you have a new chunk to add, make a function to write it,
+ * and put it in the correct location here. If you want the chunk written
+ * after the image data, put it in png_write_end(). I strongly encourage
+ * you to supply a PNG_INFO_ flag, and check info_ptr->valid before writing
+ * the chunk, as that will keep the code from breaking if you want to just
+ * write a plain PNG file. If you have long comments, I suggest writing
+ * them in png_write_end(), and compressing them.
+ */
+void PNGAPI
+png_write_info_before_PLTE(png_structrp png_ptr, png_const_inforp info_ptr)
+{
+ png_debug(1, "in png_write_info_before_PLTE");
+
+ if (png_ptr == NULL || info_ptr == NULL)
+ return;
+
+ if ((png_ptr->mode & PNG_WROTE_INFO_BEFORE_PLTE) == 0)
+ {
+ /* Write PNG signature */
+ png_write_sig(png_ptr);
+
+#ifdef PNG_MNG_FEATURES_SUPPORTED
+ if ((png_ptr->mode & PNG_HAVE_PNG_SIGNATURE) != 0 && \
+ png_ptr->mng_features_permitted != 0)
+ {
+ png_warning(png_ptr, "MNG features are not allowed in a PNG datastream");
+ png_ptr->mng_features_permitted = 0;
+ }
+#endif
+
+ /* Write IHDR information. */
+ png_write_IHDR(png_ptr, info_ptr->width, info_ptr->height,
+ info_ptr->bit_depth, info_ptr->color_type, info_ptr->compression_type,
+ info_ptr->filter_type,
+#ifdef PNG_WRITE_INTERLACING_SUPPORTED
+ info_ptr->interlace_type
+#else
+ 0
+#endif
+ );
+
+ /* The rest of these check to see if the valid field has the appropriate
+ * flag set, and if it does, writes the chunk.
+ *
+ * 1.6.0: COLORSPACE support controls the writing of these chunks too, and
+ * the chunks will be written if the WRITE routine is there and information
+ * is available in the COLORSPACE. (See png_colorspace_sync_info in png.c
+ * for where the valid flags get set.)
+ *
+ * Under certain circumstances the colorspace can be invalidated without
+ * syncing the info_struct 'valid' flags; this happens if libpng detects and
+ * error and calls png_error while the color space is being set, yet the
+ * application continues writing the PNG. So check the 'invalid' flag here
+ * too.
+ */
+#ifdef PNG_GAMMA_SUPPORTED
+# ifdef PNG_WRITE_gAMA_SUPPORTED
+ if ((info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) == 0 &&
+ (info_ptr->colorspace.flags & PNG_COLORSPACE_FROM_gAMA) != 0 &&
+ (info_ptr->valid & PNG_INFO_gAMA) != 0)
+ png_write_gAMA_fixed(png_ptr, info_ptr->colorspace.gamma);
+# endif
+#endif
+
+#ifdef PNG_COLORSPACE_SUPPORTED
+ /* Write only one of sRGB or an ICC profile. If a profile was supplied
+ * and it matches one of the known sRGB ones issue a warning.
+ */
+# ifdef PNG_WRITE_iCCP_SUPPORTED
+ if ((info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) == 0 &&
+ (info_ptr->valid & PNG_INFO_iCCP) != 0)
+ {
+# ifdef PNG_WRITE_sRGB_SUPPORTED
+ if ((info_ptr->valid & PNG_INFO_sRGB) != 0)
+ png_app_warning(png_ptr,
+ "profile matches sRGB but writing iCCP instead");
+# endif
+
+ png_write_iCCP(png_ptr, info_ptr->iccp_name,
+ info_ptr->iccp_profile);
+ }
+# ifdef PNG_WRITE_sRGB_SUPPORTED
+ else
+# endif
+# endif
+
+# ifdef PNG_WRITE_sRGB_SUPPORTED
+ if ((info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) == 0 &&
+ (info_ptr->valid & PNG_INFO_sRGB) != 0)
+ png_write_sRGB(png_ptr, info_ptr->colorspace.rendering_intent);
+# endif /* WRITE_sRGB */
+#endif /* COLORSPACE */
+
+#ifdef PNG_WRITE_sBIT_SUPPORTED
+ if ((info_ptr->valid & PNG_INFO_sBIT) != 0)
+ png_write_sBIT(png_ptr, &(info_ptr->sig_bit), info_ptr->color_type);
+#endif
+
+#ifdef PNG_COLORSPACE_SUPPORTED
+# ifdef PNG_WRITE_cHRM_SUPPORTED
+ if ((info_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) == 0 &&
+ (info_ptr->colorspace.flags & PNG_COLORSPACE_FROM_cHRM) != 0 &&
+ (info_ptr->valid & PNG_INFO_cHRM) != 0)
+ png_write_cHRM_fixed(png_ptr, &info_ptr->colorspace.end_points_xy);
+# endif
+#endif
+
+#ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED
+ write_unknown_chunks(png_ptr, info_ptr, PNG_HAVE_IHDR);
+#endif
+
+ png_ptr->mode |= PNG_WROTE_INFO_BEFORE_PLTE;
+ }
+}
+
+void PNGAPI
+png_write_info(png_structrp png_ptr, png_const_inforp info_ptr)
+{
+#if defined(PNG_WRITE_TEXT_SUPPORTED) || defined(PNG_WRITE_sPLT_SUPPORTED)
+ int i;
+#endif
+
+ png_debug(1, "in png_write_info");
+
+ if (png_ptr == NULL || info_ptr == NULL)
+ return;
+
+ png_write_info_before_PLTE(png_ptr, info_ptr);
+
+ if ((info_ptr->valid & PNG_INFO_PLTE) != 0)
+ png_write_PLTE(png_ptr, info_ptr->palette,
+ (png_uint_32)info_ptr->num_palette);
+
+ else if ((info_ptr->color_type == PNG_COLOR_TYPE_PALETTE) !=0)
+ png_error(png_ptr, "Valid palette required for paletted images");
+
+#ifdef PNG_WRITE_tRNS_SUPPORTED
+ if ((info_ptr->valid & PNG_INFO_tRNS) !=0)
+ {
+#ifdef PNG_WRITE_INVERT_ALPHA_SUPPORTED
+ /* Invert the alpha channel (in tRNS) */
+ if ((png_ptr->transformations & PNG_INVERT_ALPHA) != 0 &&
+ info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
+ {
+ int j;
+ for (j = 0; j<(int)info_ptr->num_trans; j++)
+ info_ptr->trans_alpha[j] =
+ (png_byte)(255 - info_ptr->trans_alpha[j]);
+ }
+#endif
+ png_write_tRNS(png_ptr, info_ptr->trans_alpha, &(info_ptr->trans_color),
+ info_ptr->num_trans, info_ptr->color_type);
+ }
+#endif
+#ifdef PNG_WRITE_bKGD_SUPPORTED
+ if ((info_ptr->valid & PNG_INFO_bKGD) != 0)
+ png_write_bKGD(png_ptr, &(info_ptr->background), info_ptr->color_type);
+#endif
+
+#ifdef PNG_WRITE_hIST_SUPPORTED
+ if ((info_ptr->valid & PNG_INFO_hIST) != 0)
+ png_write_hIST(png_ptr, info_ptr->hist, info_ptr->num_palette);
+#endif
+
+#ifdef PNG_WRITE_oFFs_SUPPORTED
+ if ((info_ptr->valid & PNG_INFO_oFFs) != 0)
+ png_write_oFFs(png_ptr, info_ptr->x_offset, info_ptr->y_offset,
+ info_ptr->offset_unit_type);
+#endif
+
+#ifdef PNG_WRITE_pCAL_SUPPORTED
+ if ((info_ptr->valid & PNG_INFO_pCAL) != 0)
+ png_write_pCAL(png_ptr, info_ptr->pcal_purpose, info_ptr->pcal_X0,
+ info_ptr->pcal_X1, info_ptr->pcal_type, info_ptr->pcal_nparams,
+ info_ptr->pcal_units, info_ptr->pcal_params);
+#endif
+
+#ifdef PNG_WRITE_sCAL_SUPPORTED
+ if ((info_ptr->valid & PNG_INFO_sCAL) != 0)
+ png_write_sCAL_s(png_ptr, (int)info_ptr->scal_unit,
+ info_ptr->scal_s_width, info_ptr->scal_s_height);
+#endif /* sCAL */
+
+#ifdef PNG_WRITE_pHYs_SUPPORTED
+ if ((info_ptr->valid & PNG_INFO_pHYs) != 0)
+ png_write_pHYs(png_ptr, info_ptr->x_pixels_per_unit,
+ info_ptr->y_pixels_per_unit, info_ptr->phys_unit_type);
+#endif /* pHYs */
+
+#ifdef PNG_WRITE_tIME_SUPPORTED
+ if ((info_ptr->valid & PNG_INFO_tIME) != 0)
+ {
+ png_write_tIME(png_ptr, &(info_ptr->mod_time));
+ png_ptr->mode |= PNG_WROTE_tIME;
+ }
+#endif /* tIME */
+
+#ifdef PNG_WRITE_sPLT_SUPPORTED
+ if ((info_ptr->valid & PNG_INFO_sPLT) != 0)
+ for (i = 0; i < (int)info_ptr->splt_palettes_num; i++)
+ png_write_sPLT(png_ptr, info_ptr->splt_palettes + i);
+#endif /* sPLT */
+
+#ifdef PNG_WRITE_TEXT_SUPPORTED
+ /* Check to see if we need to write text chunks */
+ for (i = 0; i < info_ptr->num_text; i++)
+ {
+ png_debug2(2, "Writing header text chunk %d, type %d", i,
+ info_ptr->text[i].compression);
+ /* An internationalized chunk? */
+ if (info_ptr->text[i].compression > 0)
+ {
+#ifdef PNG_WRITE_iTXt_SUPPORTED
+ /* Write international chunk */
+ png_write_iTXt(png_ptr,
+ info_ptr->text[i].compression,
+ info_ptr->text[i].key,
+ info_ptr->text[i].lang,
+ info_ptr->text[i].lang_key,
+ info_ptr->text[i].text);
+ /* Mark this chunk as written */
+ if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_NONE)
+ info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_NONE_WR;
+ else
+ info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_zTXt_WR;
+#else
+ png_warning(png_ptr, "Unable to write international text");
+#endif
+ }
+
+ /* If we want a compressed text chunk */
+ else if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_zTXt)
+ {
+#ifdef PNG_WRITE_zTXt_SUPPORTED
+ /* Write compressed chunk */
+ png_write_zTXt(png_ptr, info_ptr->text[i].key,
+ info_ptr->text[i].text, info_ptr->text[i].compression);
+ /* Mark this chunk as written */
+ info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_zTXt_WR;
+#else
+ png_warning(png_ptr, "Unable to write compressed text");
+#endif
+ }
+
+ else if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_NONE)
+ {
+#ifdef PNG_WRITE_tEXt_SUPPORTED
+ /* Write uncompressed chunk */
+ png_write_tEXt(png_ptr, info_ptr->text[i].key,
+ info_ptr->text[i].text,
+ 0);
+ /* Mark this chunk as written */
+ info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_NONE_WR;
+#else
+ /* Can't get here */
+ png_warning(png_ptr, "Unable to write uncompressed text");
+#endif
+ }
+ }
+#endif /* tEXt */
+
+#ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED
+ write_unknown_chunks(png_ptr, info_ptr, PNG_HAVE_PLTE);
+#endif
+}
+
+/* Writes the end of the PNG file. If you don't want to write comments or
+ * time information, you can pass NULL for info. If you already wrote these
+ * in png_write_info(), do not write them again here. If you have long
+ * comments, I suggest writing them here, and compressing them.
+ */
+void PNGAPI
+png_write_end(png_structrp png_ptr, png_inforp info_ptr)
+{
+ png_debug(1, "in png_write_end");
+
+ if (png_ptr == NULL)
+ return;
+
+ if ((png_ptr->mode & PNG_HAVE_IDAT) == 0)
+ png_error(png_ptr, "No IDATs written into file");
+
+#ifdef PNG_WRITE_CHECK_FOR_INVALID_INDEX_SUPPORTED
+ if (png_ptr->num_palette_max > png_ptr->num_palette)
+ png_benign_error(png_ptr, "Wrote palette index exceeding num_palette");
+#endif
+
+ /* See if user wants us to write information chunks */
+ if (info_ptr != NULL)
+ {
+#ifdef PNG_WRITE_TEXT_SUPPORTED
+ int i; /* local index variable */
+#endif
+#ifdef PNG_WRITE_tIME_SUPPORTED
+ /* Check to see if user has supplied a time chunk */
+ if ((info_ptr->valid & PNG_INFO_tIME) != 0 &&
+ (png_ptr->mode & PNG_WROTE_tIME) == 0)
+ png_write_tIME(png_ptr, &(info_ptr->mod_time));
+
+#endif
+#ifdef PNG_WRITE_TEXT_SUPPORTED
+ /* Loop through comment chunks */
+ for (i = 0; i < info_ptr->num_text; i++)
+ {
+ png_debug2(2, "Writing trailer text chunk %d, type %d", i,
+ info_ptr->text[i].compression);
+ /* An internationalized chunk? */
+ if (info_ptr->text[i].compression > 0)
+ {
+#ifdef PNG_WRITE_iTXt_SUPPORTED
+ /* Write international chunk */
+ png_write_iTXt(png_ptr,
+ info_ptr->text[i].compression,
+ info_ptr->text[i].key,
+ info_ptr->text[i].lang,
+ info_ptr->text[i].lang_key,
+ info_ptr->text[i].text);
+ /* Mark this chunk as written */
+ if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_NONE)
+ info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_NONE_WR;
+ else
+ info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_zTXt_WR;
+#else
+ png_warning(png_ptr, "Unable to write international text");
+#endif
+ }
+
+ else if (info_ptr->text[i].compression >= PNG_TEXT_COMPRESSION_zTXt)
+ {
+#ifdef PNG_WRITE_zTXt_SUPPORTED
+ /* Write compressed chunk */
+ png_write_zTXt(png_ptr, info_ptr->text[i].key,
+ info_ptr->text[i].text, info_ptr->text[i].compression);
+ /* Mark this chunk as written */
+ info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_zTXt_WR;
+#else
+ png_warning(png_ptr, "Unable to write compressed text");
+#endif
+ }
+
+ else if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_NONE)
+ {
+#ifdef PNG_WRITE_tEXt_SUPPORTED
+ /* Write uncompressed chunk */
+ png_write_tEXt(png_ptr, info_ptr->text[i].key,
+ info_ptr->text[i].text, 0);
+ /* Mark this chunk as written */
+ info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_NONE_WR;
+#else
+ png_warning(png_ptr, "Unable to write uncompressed text");
+#endif
+ }
+ }
+#endif
+#ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED
+ write_unknown_chunks(png_ptr, info_ptr, PNG_AFTER_IDAT);
+#endif
+ }
+
+ png_ptr->mode |= PNG_AFTER_IDAT;
+
+ /* Write end of PNG file */
+ png_write_IEND(png_ptr);
+
+ /* This flush, added in libpng-1.0.8, removed from libpng-1.0.9beta03,
+ * and restored again in libpng-1.2.30, may cause some applications that
+ * do not set png_ptr->output_flush_fn to crash. If your application
+ * experiences a problem, please try building libpng with
+ * PNG_WRITE_FLUSH_AFTER_IEND_SUPPORTED defined, and report the event to
+ * png-mng-implement at lists.sf.net .
+ */
+#ifdef PNG_WRITE_FLUSH_SUPPORTED
+# ifdef PNG_WRITE_FLUSH_AFTER_IEND_SUPPORTED
+ png_flush(png_ptr);
+# endif
+#endif
+}
+
+#ifdef PNG_CONVERT_tIME_SUPPORTED
+void PNGAPI
+png_convert_from_struct_tm(png_timep ptime, PNG_CONST struct tm * ttime)
+{
+ png_debug(1, "in png_convert_from_struct_tm");
+
+ ptime->year = (png_uint_16)(1900 + ttime->tm_year);
+ ptime->month = (png_byte)(ttime->tm_mon + 1);
+ ptime->day = (png_byte)ttime->tm_mday;
+ ptime->hour = (png_byte)ttime->tm_hour;
+ ptime->minute = (png_byte)ttime->tm_min;
+ ptime->second = (png_byte)ttime->tm_sec;
+}
+
+void PNGAPI
+png_convert_from_time_t(png_timep ptime, time_t ttime)
+{
+ struct tm *tbuf;
+
+ png_debug(1, "in png_convert_from_time_t");
+
+ tbuf = gmtime(&ttime);
+ png_convert_from_struct_tm(ptime, tbuf);
+}
+#endif
+
+/* Initialize png_ptr structure, and allocate any memory needed */
+PNG_FUNCTION(png_structp,PNGAPI
+png_create_write_struct,(png_const_charp user_png_ver, png_voidp error_ptr,
+ png_error_ptr error_fn, png_error_ptr warn_fn),PNG_ALLOCATED)
+{
+#ifndef PNG_USER_MEM_SUPPORTED
+ png_structrp png_ptr = png_create_png_struct(user_png_ver, error_ptr,
+ error_fn, warn_fn, NULL, NULL, NULL);
+#else
+ return png_create_write_struct_2(user_png_ver, error_ptr, error_fn,
+ warn_fn, NULL, NULL, NULL);
+}
+
+/* Alternate initialize png_ptr structure, and allocate any memory needed */
+PNG_FUNCTION(png_structp,PNGAPI
+png_create_write_struct_2,(png_const_charp user_png_ver, png_voidp error_ptr,
+ png_error_ptr error_fn, png_error_ptr warn_fn, png_voidp mem_ptr,
+ png_malloc_ptr malloc_fn, png_free_ptr free_fn),PNG_ALLOCATED)
+{
+ png_structrp png_ptr = png_create_png_struct(user_png_ver, error_ptr,
+ error_fn, warn_fn, mem_ptr, malloc_fn, free_fn);
+#endif /* USER_MEM */
+ if (png_ptr != NULL)
+ {
+ /* Set the zlib control values to defaults; they can be overridden by the
+ * application after the struct has been created.
+ */
+ png_ptr->zbuffer_size = PNG_ZBUF_SIZE;
+
+ /* The 'zlib_strategy' setting is irrelevant because png_default_claim in
+ * pngwutil.c defaults it according to whether or not filters will be
+ * used, and ignores this setting.
+ */
+ png_ptr->zlib_strategy = PNG_Z_DEFAULT_STRATEGY;
+ png_ptr->zlib_level = PNG_Z_DEFAULT_COMPRESSION;
+ png_ptr->zlib_mem_level = 8;
+ png_ptr->zlib_window_bits = 15;
+ png_ptr->zlib_method = 8;
+
+#ifdef PNG_WRITE_COMPRESSED_TEXT_SUPPORTED
+ png_ptr->zlib_text_strategy = PNG_TEXT_Z_DEFAULT_STRATEGY;
+ png_ptr->zlib_text_level = PNG_TEXT_Z_DEFAULT_COMPRESSION;
+ png_ptr->zlib_text_mem_level = 8;
+ png_ptr->zlib_text_window_bits = 15;
+ png_ptr->zlib_text_method = 8;
+#endif /* WRITE_COMPRESSED_TEXT */
+
+ /* This is a highly dubious configuration option; by default it is off,
+ * but it may be appropriate for private builds that are testing
+ * extensions not conformant to the current specification, or of
+ * applications that must not fail to write at all costs!
+ */
+#ifdef PNG_BENIGN_WRITE_ERRORS_SUPPORTED
+ /* In stable builds only warn if an application error can be completely
+ * handled.
+ */
+ png_ptr->flags |= PNG_FLAG_BENIGN_ERRORS_WARN;
+#endif
+
+ /* App warnings are warnings in release (or release candidate) builds but
+ * are errors during development.
+ */
+#if PNG_LIBPNG_BUILD_BASE_TYPE >= PNG_LIBPNG_BUILD_RC
+ png_ptr->flags |= PNG_FLAG_APP_WARNINGS_WARN;
+#endif
+
+ /* TODO: delay this, it can be done in png_init_io() (if the app doesn't
+ * do it itself) avoiding setting the default function if it is not
+ * required.
+ */
+ png_set_write_fn(png_ptr, NULL, NULL, NULL);
+ }
+
+ return png_ptr;
+}
+
+
+/* Write a few rows of image data. If the image is interlaced,
+ * either you will have to write the 7 sub images, or, if you
+ * have called png_set_interlace_handling(), you will have to
+ * "write" the image seven times.
+ */
+void PNGAPI
+png_write_rows(png_structrp png_ptr, png_bytepp row,
+ png_uint_32 num_rows)
+{
+ png_uint_32 i; /* row counter */
+ png_bytepp rp; /* row pointer */
+
+ png_debug(1, "in png_write_rows");
+
+ if (png_ptr == NULL)
+ return;
+
+ /* Loop through the rows */
+ for (i = 0, rp = row; i < num_rows; i++, rp++)
+ {
+ png_write_row(png_ptr, *rp);
+ }
+}
+
+/* Write the image. You only need to call this function once, even
+ * if you are writing an interlaced image.
+ */
+void PNGAPI
+png_write_image(png_structrp png_ptr, png_bytepp image)
+{
+ png_uint_32 i; /* row index */
+ int pass, num_pass; /* pass variables */
+ png_bytepp rp; /* points to current row */
+
+ if (png_ptr == NULL)
+ return;
+
+ png_debug(1, "in png_write_image");
+
+#ifdef PNG_WRITE_INTERLACING_SUPPORTED
+ /* Initialize interlace handling. If image is not interlaced,
+ * this will set pass to 1
+ */
+ num_pass = png_set_interlace_handling(png_ptr);
+#else
+ num_pass = 1;
+#endif
+ /* Loop through passes */
+ for (pass = 0; pass < num_pass; pass++)
+ {
+ /* Loop through image */
+ for (i = 0, rp = image; i < png_ptr->height; i++, rp++)
+ {
+ png_write_row(png_ptr, *rp);
+ }
+ }
+}
+
+#ifdef PNG_MNG_FEATURES_SUPPORTED
+/* Performs intrapixel differencing */
+static void
+png_do_write_intrapixel(png_row_infop row_info, png_bytep row)
+{
+ png_debug(1, "in png_do_write_intrapixel");
+
+ if ((row_info->color_type & PNG_COLOR_MASK_COLOR) != 0)
+ {
+ int bytes_per_pixel;
+ png_uint_32 row_width = row_info->width;
+ if (row_info->bit_depth == 8)
+ {
+ png_bytep rp;
+ png_uint_32 i;
+
+ if (row_info->color_type == PNG_COLOR_TYPE_RGB)
+ bytes_per_pixel = 3;
+
+ else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+ bytes_per_pixel = 4;
+
+ else
+ return;
+
+ for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel)
+ {
+ *(rp) = (png_byte)(*rp - *(rp + 1));
+ *(rp + 2) = (png_byte)(*(rp + 2) - *(rp + 1));
+ }
+ }
+
+#ifdef PNG_WRITE_16BIT_SUPPORTED
+ else if (row_info->bit_depth == 16)
+ {
+ png_bytep rp;
+ png_uint_32 i;
+
+ if (row_info->color_type == PNG_COLOR_TYPE_RGB)
+ bytes_per_pixel = 6;
+
+ else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+ bytes_per_pixel = 8;
+
+ else
+ return;
+
+ for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel)
+ {
+ png_uint_32 s0 = (*(rp ) << 8) | *(rp + 1);
+ png_uint_32 s1 = (*(rp + 2) << 8) | *(rp + 3);
+ png_uint_32 s2 = (*(rp + 4) << 8) | *(rp + 5);
+ png_uint_32 red = (png_uint_32)((s0 - s1) & 0xffffL);
+ png_uint_32 blue = (png_uint_32)((s2 - s1) & 0xffffL);
+ *(rp ) = (png_byte)(red >> 8);
+ *(rp + 1) = (png_byte)red;
+ *(rp + 4) = (png_byte)(blue >> 8);
+ *(rp + 5) = (png_byte)blue;
+ }
+ }
+#endif /* WRITE_16BIT */
+ }
+}
+#endif /* MNG_FEATURES */
+
+/* Called by user to write a row of image data */
+void PNGAPI
+png_write_row(png_structrp png_ptr, png_const_bytep row)
+{
+ /* 1.5.6: moved from png_struct to be a local structure: */
+ png_row_info row_info;
+
+ if (png_ptr == NULL)
+ return;
+
+ png_debug2(1, "in png_write_row (row %u, pass %d)",
+ png_ptr->row_number, png_ptr->pass);
+
+ /* Initialize transformations and other stuff if first time */
+ if (png_ptr->row_number == 0 && png_ptr->pass == 0)
+ {
+ /* Make sure we wrote the header info */
+ if ((png_ptr->mode & PNG_WROTE_INFO_BEFORE_PLTE) == 0)
+ png_error(png_ptr,
+ "png_write_info was never called before png_write_row");
+
+ /* Check for transforms that have been set but were defined out */
+#if !defined(PNG_WRITE_INVERT_SUPPORTED) && defined(PNG_READ_INVERT_SUPPORTED)
+ if ((png_ptr->transformations & PNG_INVERT_MONO) != 0)
+ png_warning(png_ptr, "PNG_WRITE_INVERT_SUPPORTED is not defined");
+#endif
+
+#if !defined(PNG_WRITE_FILLER_SUPPORTED) && defined(PNG_READ_FILLER_SUPPORTED)
+ if ((png_ptr->transformations & PNG_FILLER) != 0)
+ png_warning(png_ptr, "PNG_WRITE_FILLER_SUPPORTED is not defined");
+#endif
+#if !defined(PNG_WRITE_PACKSWAP_SUPPORTED) && \
+ defined(PNG_READ_PACKSWAP_SUPPORTED)
+ if ((png_ptr->transformations & PNG_PACKSWAP) != 0)
+ png_warning(png_ptr,
+ "PNG_WRITE_PACKSWAP_SUPPORTED is not defined");
+#endif
+
+#if !defined(PNG_WRITE_PACK_SUPPORTED) && defined(PNG_READ_PACK_SUPPORTED)
+ if ((png_ptr->transformations & PNG_PACK) != 0)
+ png_warning(png_ptr, "PNG_WRITE_PACK_SUPPORTED is not defined");
+#endif
+
+#if !defined(PNG_WRITE_SHIFT_SUPPORTED) && defined(PNG_READ_SHIFT_SUPPORTED)
+ if ((png_ptr->transformations & PNG_SHIFT) != 0)
+ png_warning(png_ptr, "PNG_WRITE_SHIFT_SUPPORTED is not defined");
+#endif
+
+#if !defined(PNG_WRITE_BGR_SUPPORTED) && defined(PNG_READ_BGR_SUPPORTED)
+ if ((png_ptr->transformations & PNG_BGR) != 0)
+ png_warning(png_ptr, "PNG_WRITE_BGR_SUPPORTED is not defined");
+#endif
+
+#if !defined(PNG_WRITE_SWAP_SUPPORTED) && defined(PNG_READ_SWAP_SUPPORTED)
+ if ((png_ptr->transformations & PNG_SWAP_BYTES) != 0)
+ png_warning(png_ptr, "PNG_WRITE_SWAP_SUPPORTED is not defined");
+#endif
+
+ png_write_start_row(png_ptr);
+ }
+
+#ifdef PNG_WRITE_INTERLACING_SUPPORTED
+ /* If interlaced and not interested in row, return */
+ if (png_ptr->interlaced != 0 &&
+ (png_ptr->transformations & PNG_INTERLACE) != 0)
+ {
+ switch (png_ptr->pass)
+ {
+ case 0:
+ if ((png_ptr->row_number & 0x07) != 0)
+ {
+ png_write_finish_row(png_ptr);
+ return;
+ }
+ break;
+
+ case 1:
+ if ((png_ptr->row_number & 0x07) != 0 || png_ptr->width < 5)
+ {
+ png_write_finish_row(png_ptr);
+ return;
+ }
+ break;
+
+ case 2:
+ if ((png_ptr->row_number & 0x07) != 4)
+ {
+ png_write_finish_row(png_ptr);
+ return;
+ }
+ break;
+
+ case 3:
+ if ((png_ptr->row_number & 0x03) != 0 || png_ptr->width < 3)
+ {
+ png_write_finish_row(png_ptr);
+ return;
+ }
+ break;
+
+ case 4:
+ if ((png_ptr->row_number & 0x03) != 2)
+ {
+ png_write_finish_row(png_ptr);
+ return;
+ }
+ break;
+
+ case 5:
+ if ((png_ptr->row_number & 0x01) != 0 || png_ptr->width < 2)
+ {
+ png_write_finish_row(png_ptr);
+ return;
+ }
+ break;
+
+ case 6:
+ if ((png_ptr->row_number & 0x01) == 0)
+ {
+ png_write_finish_row(png_ptr);
+ return;
+ }
+ break;
+
+ default: /* error: ignore it */
+ break;
+ }
+ }
+#endif
+
+ /* Set up row info for transformations */
+ row_info.color_type = png_ptr->color_type;
+ row_info.width = png_ptr->usr_width;
+ row_info.channels = png_ptr->usr_channels;
+ row_info.bit_depth = png_ptr->usr_bit_depth;
+ row_info.pixel_depth = (png_byte)(row_info.bit_depth * row_info.channels);
+ row_info.rowbytes = PNG_ROWBYTES(row_info.pixel_depth, row_info.width);
+
+ png_debug1(3, "row_info->color_type = %d", row_info.color_type);
+ png_debug1(3, "row_info->width = %u", row_info.width);
+ png_debug1(3, "row_info->channels = %d", row_info.channels);
+ png_debug1(3, "row_info->bit_depth = %d", row_info.bit_depth);
+ png_debug1(3, "row_info->pixel_depth = %d", row_info.pixel_depth);
+ png_debug1(3, "row_info->rowbytes = %lu", (unsigned long)row_info.rowbytes);
+
+ /* Copy user's row into buffer, leaving room for filter byte. */
+ memcpy(png_ptr->row_buf + 1, row, row_info.rowbytes);
+
+#ifdef PNG_WRITE_INTERLACING_SUPPORTED
+ /* Handle interlacing */
+ if (png_ptr->interlaced && png_ptr->pass < 6 &&
+ (png_ptr->transformations & PNG_INTERLACE) != 0)
+ {
+ png_do_write_interlace(&row_info, png_ptr->row_buf + 1, png_ptr->pass);
+ /* This should always get caught above, but still ... */
+ if (row_info.width == 0)
+ {
+ png_write_finish_row(png_ptr);
+ return;
+ }
+ }
+#endif
+
+#ifdef PNG_WRITE_TRANSFORMS_SUPPORTED
+ /* Handle other transformations */
+ if (png_ptr->transformations != 0)
+ png_do_write_transformations(png_ptr, &row_info);
+#endif
+
+ /* At this point the row_info pixel depth must match the 'transformed' depth,
+ * which is also the output depth.
+ */
+ if (row_info.pixel_depth != png_ptr->pixel_depth ||
+ row_info.pixel_depth != png_ptr->transformed_pixel_depth)
+ png_error(png_ptr, "internal write transform logic error");
+
+#ifdef PNG_MNG_FEATURES_SUPPORTED
+ /* Write filter_method 64 (intrapixel differencing) only if
+ * 1. Libpng was compiled with PNG_MNG_FEATURES_SUPPORTED and
+ * 2. Libpng did not write a PNG signature (this filter_method is only
+ * used in PNG datastreams that are embedded in MNG datastreams) and
+ * 3. The application called png_permit_mng_features with a mask that
+ * included PNG_FLAG_MNG_FILTER_64 and
+ * 4. The filter_method is 64 and
+ * 5. The color_type is RGB or RGBA
+ */
+ if ((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) != 0 &&
+ (png_ptr->filter_type == PNG_INTRAPIXEL_DIFFERENCING))
+ {
+ /* Intrapixel differencing */
+ png_do_write_intrapixel(&row_info, png_ptr->row_buf + 1);
+ }
+#endif
+
+/* Added at libpng-1.5.10 */
+#ifdef PNG_WRITE_CHECK_FOR_INVALID_INDEX_SUPPORTED
+ /* Check for out-of-range palette index */
+ if (row_info.color_type == PNG_COLOR_TYPE_PALETTE &&
+ png_ptr->num_palette_max >= 0)
+ png_do_check_palette_indexes(png_ptr, &row_info);
+#endif
+
+ /* Find a filter if necessary, filter the row and write it out. */
+ png_write_find_filter(png_ptr, &row_info);
+
+ if (png_ptr->write_row_fn != NULL)
+ (*(png_ptr->write_row_fn))(png_ptr, png_ptr->row_number, png_ptr->pass);
+}
+
+#ifdef PNG_WRITE_FLUSH_SUPPORTED
+/* Set the automatic flush interval or 0 to turn flushing off */
+void PNGAPI
+png_set_flush(png_structrp png_ptr, int nrows)
+{
+ png_debug(1, "in png_set_flush");
+
+ if (png_ptr == NULL)
+ return;
+
+ png_ptr->flush_dist = (nrows < 0 ? 0 : nrows);
+}
+
+/* Flush the current output buffers now */
+void PNGAPI
+png_write_flush(png_structrp png_ptr)
+{
+ png_debug(1, "in png_write_flush");
+
+ if (png_ptr == NULL)
+ return;
+
+ /* We have already written out all of the data */
+ if (png_ptr->row_number >= png_ptr->num_rows)
+ return;
+
+ png_compress_IDAT(png_ptr, NULL, 0, Z_SYNC_FLUSH);
+ png_ptr->flush_rows = 0;
+ png_flush(png_ptr);
+}
+#endif /* WRITE_FLUSH */
+
+#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
+static void png_reset_filter_heuristics(png_structrp png_ptr);/* forward decl */
+#endif
+
+/* Free any memory used in png_ptr struct without freeing the struct itself. */
+static void
+png_write_destroy(png_structrp png_ptr)
+{
+ png_debug(1, "in png_write_destroy");
+
+ /* Free any memory zlib uses */
+ if ((png_ptr->flags & PNG_FLAG_ZSTREAM_INITIALIZED) != 0)
+ deflateEnd(&png_ptr->zstream);
+
+ /* Free our memory. png_free checks NULL for us. */
+ png_free_buffer_list(png_ptr, &png_ptr->zbuffer_list);
+ png_free(png_ptr, png_ptr->row_buf);
+ png_ptr->row_buf = NULL;
+#ifdef PNG_WRITE_FILTER_SUPPORTED
+ png_free(png_ptr, png_ptr->prev_row);
+ png_free(png_ptr, png_ptr->sub_row);
+ png_free(png_ptr, png_ptr->up_row);
+ png_free(png_ptr, png_ptr->avg_row);
+ png_free(png_ptr, png_ptr->paeth_row);
+ png_ptr->prev_row = NULL;
+ png_ptr->sub_row = NULL;
+ png_ptr->up_row = NULL;
+ png_ptr->avg_row = NULL;
+ png_ptr->paeth_row = NULL;
+#endif
+
+#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
+ /* Use this to save a little code space, it doesn't free the filter_costs */
+ png_reset_filter_heuristics(png_ptr);
+ png_free(png_ptr, png_ptr->filter_costs);
+ png_free(png_ptr, png_ptr->inv_filter_costs);
+ png_ptr->filter_costs = NULL;
+ png_ptr->inv_filter_costs = NULL;
+#endif
+
+#ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
+ png_free(png_ptr, png_ptr->chunk_list);
+ png_ptr->chunk_list = NULL;
+#endif
+
+ /* The error handling and memory handling information is left intact at this
+ * point: the jmp_buf may still have to be freed. See png_destroy_png_struct
+ * for how this happens.
+ */
+}
+
+/* Free all memory used by the write.
+ * In libpng 1.6.0 this API changed quietly to no longer accept a NULL value for
+ * *png_ptr_ptr. Prior to 1.6.0 it would accept such a value and it would free
+ * the passed in info_structs but it would quietly fail to free any of the data
+ * inside them. In 1.6.0 it quietly does nothing (it has to be quiet because it
+ * has no png_ptr.)
+ */
+void PNGAPI
+png_destroy_write_struct(png_structpp png_ptr_ptr, png_infopp info_ptr_ptr)
+{
+ png_debug(1, "in png_destroy_write_struct");
+
+ if (png_ptr_ptr != NULL)
+ {
+ png_structrp png_ptr = *png_ptr_ptr;
+
+ if (png_ptr != NULL) /* added in libpng 1.6.0 */
+ {
+ png_destroy_info_struct(png_ptr, info_ptr_ptr);
+
+ *png_ptr_ptr = NULL;
+ png_write_destroy(png_ptr);
+ png_destroy_png_struct(png_ptr);
+ }
+ }
+}
+
+/* Allow the application to select one or more row filters to use. */
+void PNGAPI
+png_set_filter(png_structrp png_ptr, int method, int filters)
+{
+ png_debug(1, "in png_set_filter");
+
+ if (png_ptr == NULL)
+ return;
+
+#ifdef PNG_MNG_FEATURES_SUPPORTED
+ if ((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) != 0 &&
+ (method == PNG_INTRAPIXEL_DIFFERENCING))
+ method = PNG_FILTER_TYPE_BASE;
+
+#endif
+ if (method == PNG_FILTER_TYPE_BASE)
+ {
+ switch (filters & (PNG_ALL_FILTERS | 0x07))
+ {
+#ifdef PNG_WRITE_FILTER_SUPPORTED
+ case 5:
+ case 6:
+ case 7: png_app_error(png_ptr, "Unknown row filter for method 0");
+ /* FALL THROUGH */
+#endif /* WRITE_FILTER */
+ case PNG_FILTER_VALUE_NONE:
+ png_ptr->do_filter = PNG_FILTER_NONE; break;
+
+#ifdef PNG_WRITE_FILTER_SUPPORTED
+ case PNG_FILTER_VALUE_SUB:
+ png_ptr->do_filter = PNG_FILTER_SUB; break;
+
+ case PNG_FILTER_VALUE_UP:
+ png_ptr->do_filter = PNG_FILTER_UP; break;
+
+ case PNG_FILTER_VALUE_AVG:
+ png_ptr->do_filter = PNG_FILTER_AVG; break;
+
+ case PNG_FILTER_VALUE_PAETH:
+ png_ptr->do_filter = PNG_FILTER_PAETH; break;
+
+ default:
+ png_ptr->do_filter = (png_byte)filters; break;
+#else
+ default:
+ png_app_error(png_ptr, "Unknown row filter for method 0");
+#endif /* WRITE_FILTER */
+ }
+
+ /* If we have allocated the row_buf, this means we have already started
+ * with the image and we should have allocated all of the filter buffers
+ * that have been selected. If prev_row isn't already allocated, then
+ * it is too late to start using the filters that need it, since we
+ * will be missing the data in the previous row. If an application
+ * wants to start and stop using particular filters during compression,
+ * it should start out with all of the filters, and then remove them
+ * or add them back after the start of compression.
+ */
+ if (png_ptr->row_buf != NULL)
+ {
+#ifdef PNG_WRITE_FILTER_SUPPORTED
+ if ((png_ptr->do_filter & PNG_FILTER_SUB) != 0 &&
+ png_ptr->sub_row == NULL)
+ {
+ png_ptr->sub_row = (png_bytep)png_malloc(png_ptr,
+ (png_ptr->rowbytes + 1));
+ png_ptr->sub_row[0] = PNG_FILTER_VALUE_SUB;
+ }
+
+ if ((png_ptr->do_filter & PNG_FILTER_UP) != 0 &&
+ png_ptr->up_row == NULL)
+ {
+ if (png_ptr->prev_row == NULL)
+ {
+ png_warning(png_ptr, "Can't add Up filter after starting");
+ png_ptr->do_filter = (png_byte)(png_ptr->do_filter &
+ ~PNG_FILTER_UP);
+ }
+
+ else
+ {
+ png_ptr->up_row = (png_bytep)png_malloc(png_ptr,
+ (png_ptr->rowbytes + 1));
+ png_ptr->up_row[0] = PNG_FILTER_VALUE_UP;
+ }
+ }
+
+ if ((png_ptr->do_filter & PNG_FILTER_AVG) != 0 &&
+ png_ptr->avg_row == NULL)
+ {
+ if (png_ptr->prev_row == NULL)
+ {
+ png_warning(png_ptr, "Can't add Average filter after starting");
+ png_ptr->do_filter = (png_byte)(png_ptr->do_filter &
+ ~PNG_FILTER_AVG);
+ }
+
+ else
+ {
+ png_ptr->avg_row = (png_bytep)png_malloc(png_ptr,
+ (png_ptr->rowbytes + 1));
+ png_ptr->avg_row[0] = PNG_FILTER_VALUE_AVG;
+ }
+ }
+
+ if ((png_ptr->do_filter & PNG_FILTER_PAETH) != 0 &&
+ png_ptr->paeth_row == NULL)
+ {
+ if (png_ptr->prev_row == NULL)
+ {
+ png_warning(png_ptr, "Can't add Paeth filter after starting");
+ png_ptr->do_filter &= (png_byte)(~PNG_FILTER_PAETH);
+ }
+
+ else
+ {
+ png_ptr->paeth_row = (png_bytep)png_malloc(png_ptr,
+ (png_ptr->rowbytes + 1));
+ png_ptr->paeth_row[0] = PNG_FILTER_VALUE_PAETH;
+ }
+ }
+
+ if (png_ptr->do_filter == PNG_NO_FILTERS)
+#endif /* WRITE_FILTER */
+ png_ptr->do_filter = PNG_FILTER_NONE;
+ }
+ }
+ else
+ png_error(png_ptr, "Unknown custom filter method");
+}
+
+/* This allows us to influence the way in which libpng chooses the "best"
+ * filter for the current scanline. While the "minimum-sum-of-absolute-
+ * differences metric is relatively fast and effective, there is some
+ * question as to whether it can be improved upon by trying to keep the
+ * filtered data going to zlib more consistent, hopefully resulting in
+ * better compression.
+ */
+#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED /* GRR 970116 */
+/* Convenience reset API. */
+static void
+png_reset_filter_heuristics(png_structrp png_ptr)
+{
+ /* Clear out any old values in the 'weights' - this must be done because if
+ * the app calls set_filter_heuristics multiple times with different
+ * 'num_weights' values we would otherwise potentially have wrong sized
+ * arrays.
+ */
+ png_ptr->num_prev_filters = 0;
+ png_ptr->heuristic_method = PNG_FILTER_HEURISTIC_UNWEIGHTED;
+ if (png_ptr->prev_filters != NULL)
+ {
+ png_bytep old = png_ptr->prev_filters;
+ png_ptr->prev_filters = NULL;
+ png_free(png_ptr, old);
+ }
+ if (png_ptr->filter_weights != NULL)
+ {
+ png_uint_16p old = png_ptr->filter_weights;
+ png_ptr->filter_weights = NULL;
+ png_free(png_ptr, old);
+ }
+
+ if (png_ptr->inv_filter_weights != NULL)
+ {
+ png_uint_16p old = png_ptr->inv_filter_weights;
+ png_ptr->inv_filter_weights = NULL;
+ png_free(png_ptr, old);
+ }
+
+ /* Leave the filter_costs - this array is fixed size. */
+}
+
+static int
+png_init_filter_heuristics(png_structrp png_ptr, int heuristic_method,
+ int num_weights)
+{
+ if (png_ptr == NULL)
+ return 0;
+
+ /* Clear out the arrays */
+ png_reset_filter_heuristics(png_ptr);
+
+ /* Check arguments; the 'reset' function makes the correct settings for the
+ * unweighted case, but we must handle the weight case by initializing the
+ * arrays for the caller.
+ */
+ if (heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
+ {
+ int i;
+
+ if (num_weights > 0)
+ {
+ png_ptr->prev_filters = (png_bytep)png_malloc(png_ptr,
+ (png_uint_32)((sizeof (png_byte)) * num_weights));
+
+ /* To make sure that the weighting starts out fairly */
+ for (i = 0; i < num_weights; i++)
+ {
+ png_ptr->prev_filters[i] = 255;
+ }
+
+ png_ptr->filter_weights = (png_uint_16p)png_malloc(png_ptr,
+ (png_uint_32)((sizeof (png_uint_16)) * num_weights));
+
+ png_ptr->inv_filter_weights = (png_uint_16p)png_malloc(png_ptr,
+ (png_uint_32)((sizeof (png_uint_16)) * num_weights));
+
+ for (i = 0; i < num_weights; i++)
+ {
+ png_ptr->inv_filter_weights[i] =
+ png_ptr->filter_weights[i] = PNG_WEIGHT_FACTOR;
+ }
+
+ /* Safe to set this now */
+ png_ptr->num_prev_filters = (png_byte)num_weights;
+ }
+
+ /* If, in the future, there are other filter methods, this would
+ * need to be based on png_ptr->filter.
+ */
+ if (png_ptr->filter_costs == NULL)
+ {
+ png_ptr->filter_costs = (png_uint_16p)png_malloc(png_ptr,
+ (png_uint_32)((sizeof (png_uint_16)) * PNG_FILTER_VALUE_LAST));
+
+ png_ptr->inv_filter_costs = (png_uint_16p)png_malloc(png_ptr,
+ (png_uint_32)((sizeof (png_uint_16)) * PNG_FILTER_VALUE_LAST));
+ }
+
+ for (i = 0; i < PNG_FILTER_VALUE_LAST; i++)
+ {
+ png_ptr->inv_filter_costs[i] =
+ png_ptr->filter_costs[i] = PNG_COST_FACTOR;
+ }
+
+ /* All the arrays are inited, safe to set this: */
+ png_ptr->heuristic_method = PNG_FILTER_HEURISTIC_WEIGHTED;
+
+ /* Return the 'ok' code. */
+ return 1;
+ }
+ else if (heuristic_method == PNG_FILTER_HEURISTIC_DEFAULT ||
+ heuristic_method == PNG_FILTER_HEURISTIC_UNWEIGHTED)
+ {
+ return 1;
+ }
+ else
+ {
+ png_warning(png_ptr, "Unknown filter heuristic method");
+ return 0;
+ }
+}
+
+/* Provide floating and fixed point APIs */
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+void PNGAPI
+png_set_filter_heuristics(png_structrp png_ptr, int heuristic_method,
+ int num_weights, png_const_doublep filter_weights,
+ png_const_doublep filter_costs)
+{
+ png_debug(1, "in png_set_filter_heuristics");
+
+ /* The internal API allocates all the arrays and ensures that the elements of
+ * those arrays are set to the default value.
+ */
+ if (png_init_filter_heuristics(png_ptr, heuristic_method, num_weights) == 0)
+ return;
+
+ /* If using the weighted method copy in the weights. */
+ if (heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
+ {
+ int i;
+ for (i = 0; i < num_weights; i++)
+ {
+ if (filter_weights[i] <= 0.0)
+ {
+ png_ptr->inv_filter_weights[i] =
+ png_ptr->filter_weights[i] = PNG_WEIGHT_FACTOR;
+ }
+
+ else
+ {
+ png_ptr->inv_filter_weights[i] =
+ (png_uint_16)(PNG_WEIGHT_FACTOR*filter_weights[i]+.5);
+
+ png_ptr->filter_weights[i] =
+ (png_uint_16)(PNG_WEIGHT_FACTOR/filter_weights[i]+.5);
+ }
+ }
+
+ /* Here is where we set the relative costs of the different filters. We
+ * should take the desired compression level into account when setting
+ * the costs, so that Paeth, for instance, has a high relative cost at low
+ * compression levels, while it has a lower relative cost at higher
+ * compression settings. The filter types are in order of increasing
+ * relative cost, so it would be possible to do this with an algorithm.
+ */
+ for (i = 0; i < PNG_FILTER_VALUE_LAST; i++) if (filter_costs[i] >= 1.0)
+ {
+ png_ptr->inv_filter_costs[i] =
+ (png_uint_16)(PNG_COST_FACTOR / filter_costs[i] + .5);
+
+ png_ptr->filter_costs[i] =
+ (png_uint_16)(PNG_COST_FACTOR * filter_costs[i] + .5);
+ }
+ }
+}
+#endif /* FLOATING_POINT */
+
+#ifdef PNG_FIXED_POINT_SUPPORTED
+void PNGAPI
+png_set_filter_heuristics_fixed(png_structrp png_ptr, int heuristic_method,
+ int num_weights, png_const_fixed_point_p filter_weights,
+ png_const_fixed_point_p filter_costs)
+{
+ png_debug(1, "in png_set_filter_heuristics_fixed");
+
+ /* The internal API allocates all the arrays and ensures that the elements of
+ * those arrays are set to the default value.
+ */
+ if (png_init_filter_heuristics(png_ptr, heuristic_method, num_weights) == 0)
+ return;
+
+ /* If using the weighted method copy in the weights. */
+ if (heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
+ {
+ int i;
+ for (i = 0; i < num_weights; i++)
+ {
+ if (filter_weights[i] <= 0)
+ {
+ png_ptr->inv_filter_weights[i] =
+ png_ptr->filter_weights[i] = PNG_WEIGHT_FACTOR;
+ }
+
+ else
+ {
+ png_ptr->inv_filter_weights[i] = (png_uint_16)
+ ((PNG_WEIGHT_FACTOR*filter_weights[i]+PNG_FP_HALF)/PNG_FP_1);
+
+ png_ptr->filter_weights[i] = (png_uint_16)((PNG_WEIGHT_FACTOR*
+ PNG_FP_1+(filter_weights[i]/2))/filter_weights[i]);
+ }
+ }
+
+ /* Here is where we set the relative costs of the different filters. We
+ * should take the desired compression level into account when setting
+ * the costs, so that Paeth, for instance, has a high relative cost at low
+ * compression levels, while it has a lower relative cost at higher
+ * compression settings. The filter types are in order of increasing
+ * relative cost, so it would be possible to do this with an algorithm.
+ */
+ for (i = 0; i < PNG_FILTER_VALUE_LAST; i++)
+ if (filter_costs[i] >= PNG_FP_1)
+ {
+ png_uint_32 tmp;
+
+ /* Use a 32 bit unsigned temporary here because otherwise the
+ * intermediate value will be a 32 bit *signed* integer (ANSI rules)
+ * and this will get the wrong answer on division.
+ */
+ tmp = PNG_COST_FACTOR*PNG_FP_1 + (filter_costs[i]/2);
+ tmp /= filter_costs[i];
+
+ png_ptr->inv_filter_costs[i] = (png_uint_16)tmp;
+
+ tmp = PNG_COST_FACTOR * filter_costs[i] + PNG_FP_HALF;
+ tmp /= PNG_FP_1;
+
+ png_ptr->filter_costs[i] = (png_uint_16)tmp;
+ }
+ }
+}
+#endif /* FIXED_POINT */
+#endif /* WRITE_WEIGHTED_FILTER */
+
+#ifdef PNG_WRITE_CUSTOMIZE_COMPRESSION_SUPPORTED
+void PNGAPI
+png_set_compression_level(png_structrp png_ptr, int level)
+{
+ png_debug(1, "in png_set_compression_level");
+
+ if (png_ptr == NULL)
+ return;
+
+ png_ptr->zlib_level = level;
+}
+
+void PNGAPI
+png_set_compression_mem_level(png_structrp png_ptr, int mem_level)
+{
+ png_debug(1, "in png_set_compression_mem_level");
+
+ if (png_ptr == NULL)
+ return;
+
+ png_ptr->zlib_mem_level = mem_level;
+}
+
+void PNGAPI
+png_set_compression_strategy(png_structrp png_ptr, int strategy)
+{
+ png_debug(1, "in png_set_compression_strategy");
+
+ if (png_ptr == NULL)
+ return;
+
+ /* The flag setting here prevents the libpng dynamic selection of strategy.
+ */
+ png_ptr->flags |= PNG_FLAG_ZLIB_CUSTOM_STRATEGY;
+ png_ptr->zlib_strategy = strategy;
+}
+
+/* If PNG_WRITE_OPTIMIZE_CMF_SUPPORTED is defined, libpng will use a
+ * smaller value of window_bits if it can do so safely.
+ */
+void PNGAPI
+png_set_compression_window_bits(png_structrp png_ptr, int window_bits)
+{
+ if (png_ptr == NULL)
+ return;
+
+ /* Prior to 1.6.0 this would warn but then set the window_bits value. This
+ * meant that negative window bits values could be selected that would cause
+ * libpng to write a non-standard PNG file with raw deflate or gzip
+ * compressed IDAT or ancillary chunks. Such files can be read and there is
+ * no warning on read, so this seems like a very bad idea.
+ */
+ if (window_bits > 15)
+ {
+ png_warning(png_ptr, "Only compression windows <= 32k supported by PNG");
+ window_bits = 15;
+ }
+
+ else if (window_bits < 8)
+ {
+ png_warning(png_ptr, "Only compression windows >= 256 supported by PNG");
+ window_bits = 8;
+ }
+
+ png_ptr->zlib_window_bits = window_bits;
+}
+
+void PNGAPI
+png_set_compression_method(png_structrp png_ptr, int method)
+{
+ png_debug(1, "in png_set_compression_method");
+
+ if (png_ptr == NULL)
+ return;
+
+ /* This would produce an invalid PNG file if it worked, but it doesn't and
+ * deflate will fault it, so it is harmless to just warn here.
+ */
+ if (method != 8)
+ png_warning(png_ptr, "Only compression method 8 is supported by PNG");
+
+ png_ptr->zlib_method = method;
+}
+#endif /* WRITE_CUSTOMIZE_COMPRESSION */
+
+/* The following were added to libpng-1.5.4 */
+#ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED
+void PNGAPI
+png_set_text_compression_level(png_structrp png_ptr, int level)
+{
+ png_debug(1, "in png_set_text_compression_level");
+
+ if (png_ptr == NULL)
+ return;
+
+ png_ptr->zlib_text_level = level;
+}
+
+void PNGAPI
+png_set_text_compression_mem_level(png_structrp png_ptr, int mem_level)
+{
+ png_debug(1, "in png_set_text_compression_mem_level");
+
+ if (png_ptr == NULL)
+ return;
+
+ png_ptr->zlib_text_mem_level = mem_level;
+}
+
+void PNGAPI
+png_set_text_compression_strategy(png_structrp png_ptr, int strategy)
+{
+ png_debug(1, "in png_set_text_compression_strategy");
+
+ if (png_ptr == NULL)
+ return;
+
+ png_ptr->zlib_text_strategy = strategy;
+}
+
+/* If PNG_WRITE_OPTIMIZE_CMF_SUPPORTED is defined, libpng will use a
+ * smaller value of window_bits if it can do so safely.
+ */
+void PNGAPI
+png_set_text_compression_window_bits(png_structrp png_ptr, int window_bits)
+{
+ if (png_ptr == NULL)
+ return;
+
+ if (window_bits > 15)
+ {
+ png_warning(png_ptr, "Only compression windows <= 32k supported by PNG");
+ window_bits = 15;
+ }
+
+ else if (window_bits < 8)
+ {
+ png_warning(png_ptr, "Only compression windows >= 256 supported by PNG");
+ window_bits = 8;
+ }
+
+ png_ptr->zlib_text_window_bits = window_bits;
+}
+
+void PNGAPI
+png_set_text_compression_method(png_structrp png_ptr, int method)
+{
+ png_debug(1, "in png_set_text_compression_method");
+
+ if (png_ptr == NULL)
+ return;
+
+ if (method != 8)
+ png_warning(png_ptr, "Only compression method 8 is supported by PNG");
+
+ png_ptr->zlib_text_method = method;
+}
+#endif /* WRITE_CUSTOMIZE_ZTXT_COMPRESSION */
+/* end of API added to libpng-1.5.4 */
+
+void PNGAPI
+png_set_write_status_fn(png_structrp png_ptr, png_write_status_ptr write_row_fn)
+{
+ if (png_ptr == NULL)
+ return;
+
+ png_ptr->write_row_fn = write_row_fn;
+}
+
+#ifdef PNG_WRITE_USER_TRANSFORM_SUPPORTED
+void PNGAPI
+png_set_write_user_transform_fn(png_structrp png_ptr, png_user_transform_ptr
+ write_user_transform_fn)
+{
+ png_debug(1, "in png_set_write_user_transform_fn");
+
+ if (png_ptr == NULL)
+ return;
+
+ png_ptr->transformations |= PNG_USER_TRANSFORM;
+ png_ptr->write_user_transform_fn = write_user_transform_fn;
+}
+#endif
+
+
+#ifdef PNG_INFO_IMAGE_SUPPORTED
+void PNGAPI
+png_write_png(png_structrp png_ptr, png_inforp info_ptr,
+ int transforms, voidp params)
+{
+ if (png_ptr == NULL || info_ptr == NULL)
+ return;
+
+ if ((info_ptr->valid & PNG_INFO_IDAT) == 0)
+ {
+ png_app_error(png_ptr, "no rows for png_write_image to write");
+ return;
+ }
+
+ /* Write the file header information. */
+ png_write_info(png_ptr, info_ptr);
+
+ /* ------ these transformations don't touch the info structure ------- */
+
+ /* Invert monochrome pixels */
+ if ((transforms & PNG_TRANSFORM_INVERT_MONO) != 0)
+#ifdef PNG_WRITE_INVERT_SUPPORTED
+ png_set_invert_mono(png_ptr);
+#else
+ png_app_error(png_ptr, "PNG_TRANSFORM_INVERT_MONO not supported");
+#endif
+
+ /* Shift the pixels up to a legal bit depth and fill in
+ * as appropriate to correctly scale the image.
+ */
+ if ((transforms & PNG_TRANSFORM_SHIFT) != 0)
+#ifdef PNG_WRITE_SHIFT_SUPPORTED
+ if ((info_ptr->valid & PNG_INFO_sBIT) != 0)
+ png_set_shift(png_ptr, &info_ptr->sig_bit);
+#else
+ png_app_error(png_ptr, "PNG_TRANSFORM_SHIFT not supported");
+#endif
+
+ /* Pack pixels into bytes */
+ if ((transforms & PNG_TRANSFORM_PACKING) != 0)
+#ifdef PNG_WRITE_PACK_SUPPORTED
+ png_set_packing(png_ptr);
+#else
+ png_app_error(png_ptr, "PNG_TRANSFORM_PACKING not supported");
+#endif
+
+ /* Swap location of alpha bytes from ARGB to RGBA */
+ if ((transforms & PNG_TRANSFORM_SWAP_ALPHA) != 0)
+#ifdef PNG_WRITE_SWAP_ALPHA_SUPPORTED
+ png_set_swap_alpha(png_ptr);
+#else
+ png_app_error(png_ptr, "PNG_TRANSFORM_SWAP_ALPHA not supported");
+#endif
+
+ /* Remove a filler (X) from XRGB/RGBX/AG/GA into to convert it into
+ * RGB, note that the code expects the input color type to be G or RGB; no
+ * alpha channel.
+ */
+ if ((transforms & (PNG_TRANSFORM_STRIP_FILLER_AFTER|
+ PNG_TRANSFORM_STRIP_FILLER_BEFORE)) != 0)
+ {
+#ifdef PNG_WRITE_FILLER_SUPPORTED
+ if ((transforms & PNG_TRANSFORM_STRIP_FILLER_AFTER) != 0)
+ {
+ if ((transforms & PNG_TRANSFORM_STRIP_FILLER_BEFORE) != 0)
+ png_app_error(png_ptr,
+ "PNG_TRANSFORM_STRIP_FILLER: BEFORE+AFTER not supported");
+
+ /* Continue if ignored - this is the pre-1.6.10 behavior */
+ png_set_filler(png_ptr, 0, PNG_FILLER_AFTER);
+ }
+
+ else if ((transforms & PNG_TRANSFORM_STRIP_FILLER_BEFORE) != 0)
+ png_set_filler(png_ptr, 0, PNG_FILLER_BEFORE);
+#else
+ png_app_error(png_ptr, "PNG_TRANSFORM_STRIP_FILLER not supported");
+#endif
+ }
+
+ /* Flip BGR pixels to RGB */
+ if ((transforms & PNG_TRANSFORM_BGR) != 0)
+#ifdef PNG_WRITE_BGR_SUPPORTED
+ png_set_bgr(png_ptr);
+#else
+ png_app_error(png_ptr, "PNG_TRANSFORM_BGR not supported");
+#endif
+
+ /* Swap bytes of 16-bit files to most significant byte first */
+ if ((transforms & PNG_TRANSFORM_SWAP_ENDIAN) != 0)
+#ifdef PNG_WRITE_SWAP_SUPPORTED
+ png_set_swap(png_ptr);
+#else
+ png_app_error(png_ptr, "PNG_TRANSFORM_SWAP_ENDIAN not supported");
+#endif
+
+ /* Swap bits of 1, 2, 4 bit packed pixel formats */
+ if ((transforms & PNG_TRANSFORM_PACKSWAP) != 0)
+#ifdef PNG_WRITE_PACKSWAP_SUPPORTED
+ png_set_packswap(png_ptr);
+#else
+ png_app_error(png_ptr, "PNG_TRANSFORM_PACKSWAP not supported");
+#endif
+
+ /* Invert the alpha channel from opacity to transparency */
+ if ((transforms & PNG_TRANSFORM_INVERT_ALPHA) != 0)
+#ifdef PNG_WRITE_INVERT_ALPHA_SUPPORTED
+ png_set_invert_alpha(png_ptr);
+#else
+ png_app_error(png_ptr, "PNG_TRANSFORM_INVERT_ALPHA not supported");
+#endif
+
+ /* ----------------------- end of transformations ------------------- */
+
+ /* Write the bits */
+ png_write_image(png_ptr, info_ptr->row_pointers);
+
+ /* It is REQUIRED to call this to finish writing the rest of the file */
+ png_write_end(png_ptr, info_ptr);
+
+ PNG_UNUSED(params)
+}
+#endif
+
+
+#ifdef PNG_SIMPLIFIED_WRITE_SUPPORTED
+#ifdef PNG_STDIO_SUPPORTED /* currently required for png_image_write_* */
+/* Initialize the write structure - general purpose utility. */
+static int
+png_image_write_init(png_imagep image)
+{
+ png_structp png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, image,
+ png_safe_error, png_safe_warning);
+
+ if (png_ptr != NULL)
+ {
+ png_infop info_ptr = png_create_info_struct(png_ptr);
+
+ if (info_ptr != NULL)
+ {
+ png_controlp control = png_voidcast(png_controlp,
+ png_malloc_warn(png_ptr, (sizeof *control)));
+
+ if (control != NULL)
+ {
+ memset(control, 0, (sizeof *control));
+
+ control->png_ptr = png_ptr;
+ control->info_ptr = info_ptr;
+ control->for_write = 1;
+
+ image->opaque = control;
+ return 1;
+ }
+
+ /* Error clean up */
+ png_destroy_info_struct(png_ptr, &info_ptr);
+ }
+
+ png_destroy_write_struct(&png_ptr, NULL);
+ }
+
+ return png_image_error(image, "png_image_write_: out of memory");
+}
+
+/* Arguments to png_image_write_main: */
+typedef struct
+{
+ /* Arguments: */
+ png_imagep image;
+ png_const_voidp buffer;
+ png_int_32 row_stride;
+ png_const_voidp colormap;
+ int convert_to_8bit;
+ /* Local variables: */
+ png_const_voidp first_row;
+ ptrdiff_t row_bytes;
+ png_voidp local_row;
+} png_image_write_control;
+
+/* Write png_uint_16 input to a 16-bit PNG; the png_ptr has already been set to
+ * do any necessary byte swapping. The component order is defined by the
+ * png_image format value.
+ */
+static int
+png_write_image_16bit(png_voidp argument)
+{
+ png_image_write_control *display = png_voidcast(png_image_write_control*,
+ argument);
+ png_imagep image = display->image;
+ png_structrp png_ptr = image->opaque->png_ptr;
+
+ png_const_uint_16p input_row = png_voidcast(png_const_uint_16p,
+ display->first_row);
+ png_uint_16p output_row = png_voidcast(png_uint_16p, display->local_row);
+ png_uint_16p row_end;
+ const int channels = (image->format & PNG_FORMAT_FLAG_COLOR) != 0 ? 3 : 1;
+ int aindex = 0;
+ png_uint_32 y = image->height;
+
+ if ((image->format & PNG_FORMAT_FLAG_ALPHA) != 0)
+ {
+# ifdef PNG_SIMPLIFIED_WRITE_AFIRST_SUPPORTED
+ if ((image->format & PNG_FORMAT_FLAG_AFIRST) != 0)
+ {
+ aindex = -1;
+ ++input_row; /* To point to the first component */
+ ++output_row;
+ }
+
+ else
+# endif
+ aindex = channels;
+ }
+
+ else
+ png_error(png_ptr, "png_write_image: internal call error");
+
+ /* Work out the output row end and count over this, note that the increment
+ * above to 'row' means that row_end can actually be beyond the end of the
+ * row; this is correct.
+ */
+ row_end = output_row + image->width * (channels+1);
+
+ while (y-- > 0)
+ {
+ png_const_uint_16p in_ptr = input_row;
+ png_uint_16p out_ptr = output_row;
+
+ while (out_ptr < row_end)
+ {
+ const png_uint_16 alpha = in_ptr[aindex];
+ png_uint_32 reciprocal = 0;
+ int c;
+
+ out_ptr[aindex] = alpha;
+
+ /* Calculate a reciprocal. The correct calculation is simply
+ * component/alpha*65535 << 15. (I.e. 15 bits of precision); this
+ * allows correct rounding by adding .5 before the shift. 'reciprocal'
+ * is only initialized when required.
+ */
+ if (alpha > 0 && alpha < 65535)
+ reciprocal = ((0xffff<<15)+(alpha>>1))/alpha;
+
+ c = channels;
+ do /* always at least one channel */
+ {
+ png_uint_16 component = *in_ptr++;
+
+ /* The following gives 65535 for an alpha of 0, which is fine,
+ * otherwise if 0/0 is represented as some other value there is more
+ * likely to be a discontinuity which will probably damage
+ * compression when moving from a fully transparent area to a
+ * nearly transparent one. (The assumption here is that opaque
+ * areas tend not to be 0 intensity.)
+ */
+ if (component >= alpha)
+ component = 65535;
+
+ /* component<alpha, so component/alpha is less than one and
+ * component*reciprocal is less than 2^31.
+ */
+ else if (component > 0 && alpha < 65535)
+ {
+ png_uint_32 calc = component * reciprocal;
+ calc += 16384; /* round to nearest */
+ component = (png_uint_16)(calc >> 15);
+ }
+
+ *out_ptr++ = component;
+ }
+ while (--c > 0);
+
+ /* Skip to next component (skip the intervening alpha channel) */
+ ++in_ptr;
+ ++out_ptr;
+ }
+
+ png_write_row(png_ptr, png_voidcast(png_const_bytep, display->local_row));
+ input_row += display->row_bytes/(sizeof (png_uint_16));
+ }
+
+ return 1;
+}
+
+/* Given 16-bit input (1 to 4 channels) write 8-bit output. If an alpha channel
+ * is present it must be removed from the components, the components are then
+ * written in sRGB encoding. No components are added or removed.
+ *
+ * Calculate an alpha reciprocal to reverse pre-multiplication. As above the
+ * calculation can be done to 15 bits of accuracy; however, the output needs to
+ * be scaled in the range 0..255*65535, so include that scaling here.
+ */
+#define UNP_RECIPROCAL(alpha) ((((0xffff*0xff)<<7)+(alpha>>1))/alpha)
+
+static png_byte
+png_unpremultiply(png_uint_32 component, png_uint_32 alpha,
+ png_uint_32 reciprocal/*from the above macro*/)
+{
+ /* The following gives 1.0 for an alpha of 0, which is fine, otherwise if 0/0
+ * is represented as some other value there is more likely to be a
+ * discontinuity which will probably damage compression when moving from a
+ * fully transparent area to a nearly transparent one. (The assumption here
+ * is that opaque areas tend not to be 0 intensity.)
+ *
+ * There is a rounding problem here; if alpha is less than 128 it will end up
+ * as 0 when scaled to 8 bits. To avoid introducing spurious colors into the
+ * output change for this too.
+ */
+ if (component >= alpha || alpha < 128)
+ return 255;
+
+ /* component<alpha, so component/alpha is less than one and
+ * component*reciprocal is less than 2^31.
+ */
+ else if (component > 0)
+ {
+ /* The test is that alpha/257 (rounded) is less than 255, the first value
+ * that becomes 255 is 65407.
+ * NOTE: this must agree with the PNG_DIV257 macro (which must, therefore,
+ * be exact!) [Could also test reciprocal != 0]
+ */
+ if (alpha < 65407)
+ {
+ component *= reciprocal;
+ component += 64; /* round to nearest */
+ component >>= 7;
+ }
+
+ else
+ component *= 255;
+
+ /* Convert the component to sRGB. */
+ return (png_byte)PNG_sRGB_FROM_LINEAR(component);
+ }
+
+ else
+ return 0;
+}
+
+static int
+png_write_image_8bit(png_voidp argument)
+{
+ png_image_write_control *display = png_voidcast(png_image_write_control*,
+ argument);
+ png_imagep image = display->image;
+ png_structrp png_ptr = image->opaque->png_ptr;
+
+ png_const_uint_16p input_row = png_voidcast(png_const_uint_16p,
+ display->first_row);
+ png_bytep output_row = png_voidcast(png_bytep, display->local_row);
+ png_uint_32 y = image->height;
+ const int channels = (image->format & PNG_FORMAT_FLAG_COLOR) != 0 ? 3 : 1;
+
+ if ((image->format & PNG_FORMAT_FLAG_ALPHA) != 0)
+ {
+ png_bytep row_end;
+ int aindex;
+
+# ifdef PNG_SIMPLIFIED_WRITE_AFIRST_SUPPORTED
+ if ((image->format & PNG_FORMAT_FLAG_AFIRST) != 0)
+ {
+ aindex = -1;
+ ++input_row; /* To point to the first component */
+ ++output_row;
+ }
+
+ else
+# endif
+ aindex = channels;
+
+ /* Use row_end in place of a loop counter: */
+ row_end = output_row + image->width * (channels+1);
+
+ while (y-- > 0)
+ {
+ png_const_uint_16p in_ptr = input_row;
+ png_bytep out_ptr = output_row;
+
+ while (out_ptr < row_end)
+ {
+ png_uint_16 alpha = in_ptr[aindex];
+ png_byte alphabyte = (png_byte)PNG_DIV257(alpha);
+ png_uint_32 reciprocal = 0;
+ int c;
+
+ /* Scale and write the alpha channel. */
+ out_ptr[aindex] = alphabyte;
+
+ if (alphabyte > 0 && alphabyte < 255)
+ reciprocal = UNP_RECIPROCAL(alpha);
+
+ c = channels;
+ do /* always at least one channel */
+ *out_ptr++ = png_unpremultiply(*in_ptr++, alpha, reciprocal);
+ while (--c > 0);
+
+ /* Skip to next component (skip the intervening alpha channel) */
+ ++in_ptr;
+ ++out_ptr;
+ } /* while out_ptr < row_end */
+
+ png_write_row(png_ptr, png_voidcast(png_const_bytep,
+ display->local_row));
+ input_row += display->row_bytes/(sizeof (png_uint_16));
+ } /* while y */
+ }
+
+ else
+ {
+ /* No alpha channel, so the row_end really is the end of the row and it
+ * is sufficient to loop over the components one by one.
+ */
+ png_bytep row_end = output_row + image->width * channels;
+
+ while (y-- > 0)
+ {
+ png_const_uint_16p in_ptr = input_row;
+ png_bytep out_ptr = output_row;
+
+ while (out_ptr < row_end)
+ {
+ png_uint_32 component = *in_ptr++;
+
+ component *= 255;
+ *out_ptr++ = (png_byte)PNG_sRGB_FROM_LINEAR(component);
+ }
+
+ png_write_row(png_ptr, output_row);
+ input_row += display->row_bytes/(sizeof (png_uint_16));
+ }
+ }
+
+ return 1;
+}
+
+static void
+png_image_set_PLTE(png_image_write_control *display)
+{
+ const png_imagep image = display->image;
+ const void *cmap = display->colormap;
+ const int entries = image->colormap_entries > 256 ? 256 :
+ (int)image->colormap_entries;
+
+ /* NOTE: the caller must check for cmap != NULL and entries != 0 */
+ const png_uint_32 format = image->format;
+ const int channels = PNG_IMAGE_SAMPLE_CHANNELS(format);
+
+# if defined(PNG_FORMAT_BGR_SUPPORTED) &&\
+ defined(PNG_SIMPLIFIED_WRITE_AFIRST_SUPPORTED)
+ const int afirst = (format & PNG_FORMAT_FLAG_AFIRST) != 0 &&
+ (format & PNG_FORMAT_FLAG_ALPHA) != 0;
+# else
+# define afirst 0
+# endif
+
+# ifdef PNG_FORMAT_BGR_SUPPORTED
+ const int bgr = (format & PNG_FORMAT_FLAG_BGR) != 0 ? 2 : 0;
+# else
+# define bgr 0
+# endif
+
+ int i, num_trans;
+ png_color palette[256];
+ png_byte tRNS[256];
+
+ memset(tRNS, 255, (sizeof tRNS));
+ memset(palette, 0, (sizeof palette));
+
+ for (i=num_trans=0; i<entries; ++i)
+ {
+ /* This gets automatically converted to sRGB with reversal of the
+ * pre-multiplication if the color-map has an alpha channel.
+ */
+ if ((format & PNG_FORMAT_FLAG_LINEAR) != 0)
+ {
+ png_const_uint_16p entry = png_voidcast(png_const_uint_16p, cmap);
+
+ entry += i * channels;
+
+ if ((channels & 1) != 0) /* no alpha */
+ {
+ if (channels >= 3) /* RGB */
+ {
+ palette[i].blue = (png_byte)PNG_sRGB_FROM_LINEAR(255 *
+ entry[(2 ^ bgr)]);
+ palette[i].green = (png_byte)PNG_sRGB_FROM_LINEAR(255 *
+ entry[1]);
+ palette[i].red = (png_byte)PNG_sRGB_FROM_LINEAR(255 *
+ entry[bgr]);
+ }
+
+ else /* Gray */
+ palette[i].blue = palette[i].red = palette[i].green =
+ (png_byte)PNG_sRGB_FROM_LINEAR(255 * *entry);
+ }
+
+ else /* alpha */
+ {
+ png_uint_16 alpha = entry[afirst ? 0 : channels-1];
+ png_byte alphabyte = (png_byte)PNG_DIV257(alpha);
+ png_uint_32 reciprocal = 0;
+
+ /* Calculate a reciprocal, as in the png_write_image_8bit code above
+ * this is designed to produce a value scaled to 255*65535 when
+ * divided by 128 (i.e. asr 7).
+ */
+ if (alphabyte > 0 && alphabyte < 255)
+ reciprocal = (((0xffff*0xff)<<7)+(alpha>>1))/alpha;
+
+ tRNS[i] = alphabyte;
+ if (alphabyte < 255)
+ num_trans = i+1;
+
+ if (channels >= 3) /* RGB */
+ {
+ palette[i].blue = png_unpremultiply(entry[afirst + (2 ^ bgr)],
+ alpha, reciprocal);
+ palette[i].green = png_unpremultiply(entry[afirst + 1], alpha,
+ reciprocal);
+ palette[i].red = png_unpremultiply(entry[afirst + bgr], alpha,
+ reciprocal);
+ }
+
+ else /* gray */
+ palette[i].blue = palette[i].red = palette[i].green =
+ png_unpremultiply(entry[afirst], alpha, reciprocal);
+ }
+ }
+
+ else /* Color-map has sRGB values */
+ {
+ png_const_bytep entry = png_voidcast(png_const_bytep, cmap);
+
+ entry += i * channels;
+
+ switch (channels)
+ {
+ case 4:
+ tRNS[i] = entry[afirst ? 0 : 3];
+ if (tRNS[i] < 255)
+ num_trans = i+1;
+ /* FALL THROUGH */
+ case 3:
+ palette[i].blue = entry[afirst + (2 ^ bgr)];
+ palette[i].green = entry[afirst + 1];
+ palette[i].red = entry[afirst + bgr];
+ break;
+
+ case 2:
+ tRNS[i] = entry[1 ^ afirst];
+ if (tRNS[i] < 255)
+ num_trans = i+1;
+ /* FALL THROUGH */
+ case 1:
+ palette[i].blue = palette[i].red = palette[i].green =
+ entry[afirst];
+ break;
+
+ default:
+ break;
+ }
+ }
+ }
+
+# ifdef afirst
+# undef afirst
+# endif
+# ifdef bgr
+# undef bgr
+# endif
+
+ png_set_PLTE(image->opaque->png_ptr, image->opaque->info_ptr, palette,
+ entries);
+
+ if (num_trans > 0)
+ png_set_tRNS(image->opaque->png_ptr, image->opaque->info_ptr, tRNS,
+ num_trans, NULL);
+
+ image->colormap_entries = entries;
+}
+
+static int
+png_image_write_main(png_voidp argument)
+{
+ png_image_write_control *display = png_voidcast(png_image_write_control*,
+ argument);
+ png_imagep image = display->image;
+ png_structrp png_ptr = image->opaque->png_ptr;
+ png_inforp info_ptr = image->opaque->info_ptr;
+ png_uint_32 format = image->format;
+
+ /* The following four ints are actually booleans */
+ int colormap = (format & PNG_FORMAT_FLAG_COLORMAP);
+ int linear = !colormap && (format & PNG_FORMAT_FLAG_LINEAR); /* input */
+ int alpha = !colormap && (format & PNG_FORMAT_FLAG_ALPHA);
+ int write_16bit = linear && !colormap && (display->convert_to_8bit == 0);
+
+# ifdef PNG_BENIGN_ERRORS_SUPPORTED
+ /* Make sure we error out on any bad situation */
+ png_set_benign_errors(png_ptr, 0/*error*/);
+# endif
+
+ /* Default the 'row_stride' parameter if required. */
+ if (display->row_stride == 0)
+ display->row_stride = PNG_IMAGE_ROW_STRIDE(*image);
+
+ /* Set the required transforms then write the rows in the correct order. */
+ if ((format & PNG_FORMAT_FLAG_COLORMAP) != 0)
+ {
+ if (display->colormap != NULL && image->colormap_entries > 0)
+ {
+ png_uint_32 entries = image->colormap_entries;
+
+ png_set_IHDR(png_ptr, info_ptr, image->width, image->height,
+ entries > 16 ? 8 : (entries > 4 ? 4 : (entries > 2 ? 2 : 1)),
+ PNG_COLOR_TYPE_PALETTE, PNG_INTERLACE_NONE,
+ PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
+
+ png_image_set_PLTE(display);
+ }
+
+ else
+ png_error(image->opaque->png_ptr,
+ "no color-map for color-mapped image");
+ }
+
+ else
+ png_set_IHDR(png_ptr, info_ptr, image->width, image->height,
+ write_16bit ? 16 : 8,
+ ((format & PNG_FORMAT_FLAG_COLOR) ? PNG_COLOR_MASK_COLOR : 0) +
+ ((format & PNG_FORMAT_FLAG_ALPHA) ? PNG_COLOR_MASK_ALPHA : 0),
+ PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
+
+ /* Counter-intuitively the data transformations must be called *after*
+ * png_write_info, not before as in the read code, but the 'set' functions
+ * must still be called before. Just set the color space information, never
+ * write an interlaced image.
+ */
+
+ if (write_16bit != 0)
+ {
+ /* The gamma here is 1.0 (linear) and the cHRM chunk matches sRGB. */
+ png_set_gAMA_fixed(png_ptr, info_ptr, PNG_GAMMA_LINEAR);
+
+ if ((image->flags & PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB) == 0)
+ png_set_cHRM_fixed(png_ptr, info_ptr,
+ /* color x y */
+ /* white */ 31270, 32900,
+ /* red */ 64000, 33000,
+ /* green */ 30000, 60000,
+ /* blue */ 15000, 6000
+ );
+ }
+
+ else if ((image->flags & PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB) == 0)
+ png_set_sRGB(png_ptr, info_ptr, PNG_sRGB_INTENT_PERCEPTUAL);
+
+ /* Else writing an 8-bit file and the *colors* aren't sRGB, but the 8-bit
+ * space must still be gamma encoded.
+ */
+ else
+ png_set_gAMA_fixed(png_ptr, info_ptr, PNG_GAMMA_sRGB_INVERSE);
+
+ /* Write the file header. */
+ png_write_info(png_ptr, info_ptr);
+
+ /* Now set up the data transformations (*after* the header is written),
+ * remove the handled transformations from the 'format' flags for checking.
+ *
+ * First check for a little endian system if writing 16 bit files.
+ */
+ if (write_16bit != 0)
+ {
+ PNG_CONST png_uint_16 le = 0x0001;
+
+ if ((*(png_const_bytep) & le) != 0)
+ png_set_swap(png_ptr);
+ }
+
+# ifdef PNG_SIMPLIFIED_WRITE_BGR_SUPPORTED
+ if ((format & PNG_FORMAT_FLAG_BGR) != 0)
+ {
+ if (colormap == 0 && (format & PNG_FORMAT_FLAG_COLOR) != 0)
+ png_set_bgr(png_ptr);
+ format &= ~PNG_FORMAT_FLAG_BGR;
+ }
+# endif
+
+# ifdef PNG_SIMPLIFIED_WRITE_AFIRST_SUPPORTED
+ if ((format & PNG_FORMAT_FLAG_AFIRST) != 0)
+ {
+ if (colormap == 0 && (format & PNG_FORMAT_FLAG_ALPHA) != 0)
+ png_set_swap_alpha(png_ptr);
+ format &= ~PNG_FORMAT_FLAG_AFIRST;
+ }
+# endif
+
+ /* If there are 16 or fewer color-map entries we wrote a lower bit depth
+ * above, but the application data is still byte packed.
+ */
+ if (colormap != 0 && image->colormap_entries <= 16)
+ png_set_packing(png_ptr);
+
+ /* That should have handled all (both) the transforms. */
+ if ((format & ~(png_uint_32)(PNG_FORMAT_FLAG_COLOR | PNG_FORMAT_FLAG_LINEAR |
+ PNG_FORMAT_FLAG_ALPHA | PNG_FORMAT_FLAG_COLORMAP)) != 0)
+ png_error(png_ptr, "png_write_image: unsupported transformation");
+
+ {
+ png_const_bytep row = png_voidcast(png_const_bytep, display->buffer);
+ ptrdiff_t row_bytes = display->row_stride;
+
+ if (linear != 0)
+ row_bytes *= (sizeof (png_uint_16));
+
+ if (row_bytes < 0)
+ row += (image->height-1) * (-row_bytes);
+
+ display->first_row = row;
+ display->row_bytes = row_bytes;
+ }
+
+ /* Apply 'fast' options if the flag is set. */
+ if ((image->flags & PNG_IMAGE_FLAG_FAST) != 0)
+ {
+ png_set_filter(png_ptr, PNG_FILTER_TYPE_BASE, PNG_NO_FILTERS);
+ /* NOTE: determined by experiment using pngstest, this reflects some
+ * balance between the time to write the image once and the time to read
+ * it about 50 times. The speed-up in pngstest was about 10-20% of the
+ * total (user) time on a heavily loaded system.
+ */
+#ifdef PNG_WRITE_CUSTOMIZE_COMPRESSION_SUPPORTED
+ png_set_compression_level(png_ptr, 3);
+#endif
+ }
+
+ /* Check for the cases that currently require a pre-transform on the row
+ * before it is written. This only applies when the input is 16-bit and
+ * either there is an alpha channel or it is converted to 8-bit.
+ */
+ if ((linear != 0 && alpha != 0 ) ||
+ (colormap == 0 && display->convert_to_8bit != 0))
+ {
+ png_bytep row = png_voidcast(png_bytep, png_malloc(png_ptr,
+ png_get_rowbytes(png_ptr, info_ptr)));
+ int result;
+
+ display->local_row = row;
+ if (write_16bit != 0)
+ result = png_safe_execute(image, png_write_image_16bit, display);
+ else
+ result = png_safe_execute(image, png_write_image_8bit, display);
+ display->local_row = NULL;
+
+ png_free(png_ptr, row);
+
+ /* Skip the 'write_end' on error: */
+ if (result == 0)
+ return 0;
+ }
+
+ /* Otherwise this is the case where the input is in a format currently
+ * supported by the rest of the libpng write code; call it directly.
+ */
+ else
+ {
+ png_const_bytep row = png_voidcast(png_const_bytep, display->first_row);
+ ptrdiff_t row_bytes = display->row_bytes;
+ png_uint_32 y = image->height;
+
+ while (y-- > 0)
+ {
+ png_write_row(png_ptr, row);
+ row += row_bytes;
+ }
+ }
+
+ png_write_end(png_ptr, info_ptr);
+ return 1;
+}
+
+int PNGAPI
+png_image_write_to_stdio(png_imagep image, FILE *file, int convert_to_8bit,
+ const void *buffer, png_int_32 row_stride, const void *colormap)
+{
+ /* Write the image to the given (FILE*). */
+ if (image != NULL && image->version == PNG_IMAGE_VERSION)
+ {
+ if (file != NULL)
+ {
+ if (png_image_write_init(image) != 0)
+ {
+ png_image_write_control display;
+ int result;
+
+ /* This is slightly evil, but png_init_io doesn't do anything other
+ * than this and we haven't changed the standard IO functions so
+ * this saves a 'safe' function.
+ */
+ image->opaque->png_ptr->io_ptr = file;
+
+ memset(&display, 0, (sizeof display));
+ display.image = image;
+ display.buffer = buffer;
+ display.row_stride = row_stride;
+ display.colormap = colormap;
+ display.convert_to_8bit = convert_to_8bit;
+
+ result = png_safe_execute(image, png_image_write_main, &display);
+ png_image_free(image);
+ return result;
+ }
+
+ else
+ return 0;
+ }
+
+ else
+ return png_image_error(image,
+ "png_image_write_to_stdio: invalid argument");
+ }
+
+ else if (image != NULL)
+ return png_image_error(image,
+ "png_image_write_to_stdio: incorrect PNG_IMAGE_VERSION");
+
+ else
+ return 0;
+}
+
+int PNGAPI
+png_image_write_to_file(png_imagep image, const char *file_name,
+ int convert_to_8bit, const void *buffer, png_int_32 row_stride,
+ const void *colormap)
+{
+ /* Write the image to the named file. */
+ if (image != NULL && image->version == PNG_IMAGE_VERSION)
+ {
+ if (file_name != NULL)
+ {
+ FILE *fp = fopen(file_name, "wb");
+
+ if (fp != NULL)
+ {
+ if (png_image_write_to_stdio(image, fp, convert_to_8bit, buffer,
+ row_stride, colormap) != 0)
+ {
+ int error; /* from fflush/fclose */
+
+ /* Make sure the file is flushed correctly. */
+ if (fflush(fp) == 0 && ferror(fp) == 0)
+ {
+ if (fclose(fp) == 0)
+ return 1;
+
+ error = errno; /* from fclose */
+ }
+
+ else
+ {
+ error = errno; /* from fflush or ferror */
+ (void)fclose(fp);
+ }
+
+ (void)remove(file_name);
+ /* The image has already been cleaned up; this is just used to
+ * set the error (because the original write succeeded).
+ */
+ return png_image_error(image, strerror(error));
+ }
+
+ else
+ {
+ /* Clean up: just the opened file. */
+ (void)fclose(fp);
+ (void)remove(file_name);
+ return 0;
+ }
+ }
+
+ else
+ return png_image_error(image, strerror(errno));
+ }
+
+ else
+ return png_image_error(image,
+ "png_image_write_to_file: invalid argument");
+ }
+
+ else if (image != NULL)
+ return png_image_error(image,
+ "png_image_write_to_file: incorrect PNG_IMAGE_VERSION");
+
+ else
+ return 0;
+}
+#endif /* STDIO */
+#endif /* SIMPLIFIED_WRITE */
+#endif /* WRITE */
--- /dev/null
+
+/* pngwtran.c - transforms the data in a row for PNG writers
+ *
+ * Last changed in libpng 1.6.17 [March 26, 2015]
+ * Copyright (c) 1998-2015 Glenn Randers-Pehrson
+ * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
+ * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ */
+
+#include "pngpriv.h"
+
+#ifdef PNG_WRITE_SUPPORTED
+#ifdef PNG_WRITE_TRANSFORMS_SUPPORTED
+
+#ifdef PNG_WRITE_PACK_SUPPORTED
+/* Pack pixels into bytes. Pass the true bit depth in bit_depth. The
+ * row_info bit depth should be 8 (one pixel per byte). The channels
+ * should be 1 (this only happens on grayscale and paletted images).
+ */
+static void
+png_do_pack(png_row_infop row_info, png_bytep row, png_uint_32 bit_depth)
+{
+ png_debug(1, "in png_do_pack");
+
+ if (row_info->bit_depth == 8 &&
+ row_info->channels == 1)
+ {
+ switch ((int)bit_depth)
+ {
+ case 1:
+ {
+ png_bytep sp, dp;
+ int mask, v;
+ png_uint_32 i;
+ png_uint_32 row_width = row_info->width;
+
+ sp = row;
+ dp = row;
+ mask = 0x80;
+ v = 0;
+
+ for (i = 0; i < row_width; i++)
+ {
+ if (*sp != 0)
+ v |= mask;
+
+ sp++;
+
+ if (mask > 1)
+ mask >>= 1;
+
+ else
+ {
+ mask = 0x80;
+ *dp = (png_byte)v;
+ dp++;
+ v = 0;
+ }
+ }
+
+ if (mask != 0x80)
+ *dp = (png_byte)v;
+
+ break;
+ }
+
+ case 2:
+ {
+ png_bytep sp, dp;
+ int shift, v;
+ png_uint_32 i;
+ png_uint_32 row_width = row_info->width;
+
+ sp = row;
+ dp = row;
+ shift = 6;
+ v = 0;
+
+ for (i = 0; i < row_width; i++)
+ {
+ png_byte value;
+
+ value = (png_byte)(*sp & 0x03);
+ v |= (value << shift);
+
+ if (shift == 0)
+ {
+ shift = 6;
+ *dp = (png_byte)v;
+ dp++;
+ v = 0;
+ }
+
+ else
+ shift -= 2;
+
+ sp++;
+ }
+
+ if (shift != 6)
+ *dp = (png_byte)v;
+
+ break;
+ }
+
+ case 4:
+ {
+ png_bytep sp, dp;
+ int shift, v;
+ png_uint_32 i;
+ png_uint_32 row_width = row_info->width;
+
+ sp = row;
+ dp = row;
+ shift = 4;
+ v = 0;
+
+ for (i = 0; i < row_width; i++)
+ {
+ png_byte value;
+
+ value = (png_byte)(*sp & 0x0f);
+ v |= (value << shift);
+
+ if (shift == 0)
+ {
+ shift = 4;
+ *dp = (png_byte)v;
+ dp++;
+ v = 0;
+ }
+
+ else
+ shift -= 4;
+
+ sp++;
+ }
+
+ if (shift != 4)
+ *dp = (png_byte)v;
+
+ break;
+ }
+
+ default:
+ break;
+ }
+
+ row_info->bit_depth = (png_byte)bit_depth;
+ row_info->pixel_depth = (png_byte)(bit_depth * row_info->channels);
+ row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth,
+ row_info->width);
+ }
+}
+#endif
+
+#ifdef PNG_WRITE_SHIFT_SUPPORTED
+/* Shift pixel values to take advantage of whole range. Pass the
+ * true number of bits in bit_depth. The row should be packed
+ * according to row_info->bit_depth. Thus, if you had a row of
+ * bit depth 4, but the pixels only had values from 0 to 7, you
+ * would pass 3 as bit_depth, and this routine would translate the
+ * data to 0 to 15.
+ */
+static void
+png_do_shift(png_row_infop row_info, png_bytep row,
+ png_const_color_8p bit_depth)
+{
+ png_debug(1, "in png_do_shift");
+
+ if (row_info->color_type != PNG_COLOR_TYPE_PALETTE)
+ {
+ int shift_start[4], shift_dec[4];
+ int channels = 0;
+
+ if ((row_info->color_type & PNG_COLOR_MASK_COLOR) != 0)
+ {
+ shift_start[channels] = row_info->bit_depth - bit_depth->red;
+ shift_dec[channels] = bit_depth->red;
+ channels++;
+
+ shift_start[channels] = row_info->bit_depth - bit_depth->green;
+ shift_dec[channels] = bit_depth->green;
+ channels++;
+
+ shift_start[channels] = row_info->bit_depth - bit_depth->blue;
+ shift_dec[channels] = bit_depth->blue;
+ channels++;
+ }
+
+ else
+ {
+ shift_start[channels] = row_info->bit_depth - bit_depth->gray;
+ shift_dec[channels] = bit_depth->gray;
+ channels++;
+ }
+
+ if ((row_info->color_type & PNG_COLOR_MASK_ALPHA) != 0)
+ {
+ shift_start[channels] = row_info->bit_depth - bit_depth->alpha;
+ shift_dec[channels] = bit_depth->alpha;
+ channels++;
+ }
+
+ /* With low row depths, could only be grayscale, so one channel */
+ if (row_info->bit_depth < 8)
+ {
+ png_bytep bp = row;
+ png_size_t i;
+ unsigned int mask;
+ png_size_t row_bytes = row_info->rowbytes;
+
+ if (bit_depth->gray == 1 && row_info->bit_depth == 2)
+ mask = 0x55;
+
+ else if (row_info->bit_depth == 4 && bit_depth->gray == 3)
+ mask = 0x11;
+
+ else
+ mask = 0xff;
+
+ for (i = 0; i < row_bytes; i++, bp++)
+ {
+ int j;
+ unsigned int v, out;
+
+ v = *bp;
+ out = 0;
+
+ for (j = shift_start[0]; j > -shift_dec[0]; j -= shift_dec[0])
+ {
+ if (j > 0)
+ out |= v << j;
+
+ else
+ out |= (v >> (-j)) & mask;
+ }
+
+ *bp = (png_byte)(out & 0xff);
+ }
+ }
+
+ else if (row_info->bit_depth == 8)
+ {
+ png_bytep bp = row;
+ png_uint_32 i;
+ png_uint_32 istop = channels * row_info->width;
+
+ for (i = 0; i < istop; i++, bp++)
+ {
+
+ const unsigned int c = i%channels;
+ int j;
+ unsigned int v, out;
+
+ v = *bp;
+ out = 0;
+
+ for (j = shift_start[c]; j > -shift_dec[c]; j -= shift_dec[c])
+ {
+ if (j > 0)
+ out |= v << j;
+
+ else
+ out |= v >> (-j);
+ }
+
+ *bp = (png_byte)(out & 0xff);
+ }
+ }
+
+ else
+ {
+ png_bytep bp;
+ png_uint_32 i;
+ png_uint_32 istop = channels * row_info->width;
+
+ for (bp = row, i = 0; i < istop; i++)
+ {
+ const unsigned int c = i%channels;
+ int j;
+ unsigned int value, v;
+
+ v = png_get_uint_16(bp);
+ value = 0;
+
+ for (j = shift_start[c]; j > -shift_dec[c]; j -= shift_dec[c])
+ {
+ if (j > 0)
+ value |= v << j;
+
+ else
+ value |= v >> (-j);
+ }
+ *bp++ = (png_byte)((value >> 8) & 0xff);
+ *bp++ = (png_byte)(value & 0xff);
+ }
+ }
+ }
+}
+#endif
+
+#ifdef PNG_WRITE_SWAP_ALPHA_SUPPORTED
+static void
+png_do_write_swap_alpha(png_row_infop row_info, png_bytep row)
+{
+ png_debug(1, "in png_do_write_swap_alpha");
+
+ {
+ if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+ {
+ if (row_info->bit_depth == 8)
+ {
+ /* This converts from ARGB to RGBA */
+ png_bytep sp, dp;
+ png_uint_32 i;
+ png_uint_32 row_width = row_info->width;
+
+ for (i = 0, sp = dp = row; i < row_width; i++)
+ {
+ png_byte save = *(sp++);
+ *(dp++) = *(sp++);
+ *(dp++) = *(sp++);
+ *(dp++) = *(sp++);
+ *(dp++) = save;
+ }
+ }
+
+#ifdef PNG_WRITE_16BIT_SUPPORTED
+ else
+ {
+ /* This converts from AARRGGBB to RRGGBBAA */
+ png_bytep sp, dp;
+ png_uint_32 i;
+ png_uint_32 row_width = row_info->width;
+
+ for (i = 0, sp = dp = row; i < row_width; i++)
+ {
+ png_byte save[2];
+ save[0] = *(sp++);
+ save[1] = *(sp++);
+ *(dp++) = *(sp++);
+ *(dp++) = *(sp++);
+ *(dp++) = *(sp++);
+ *(dp++) = *(sp++);
+ *(dp++) = *(sp++);
+ *(dp++) = *(sp++);
+ *(dp++) = save[0];
+ *(dp++) = save[1];
+ }
+ }
+#endif /* WRITE_16BIT */
+ }
+
+ else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
+ {
+ if (row_info->bit_depth == 8)
+ {
+ /* This converts from AG to GA */
+ png_bytep sp, dp;
+ png_uint_32 i;
+ png_uint_32 row_width = row_info->width;
+
+ for (i = 0, sp = dp = row; i < row_width; i++)
+ {
+ png_byte save = *(sp++);
+ *(dp++) = *(sp++);
+ *(dp++) = save;
+ }
+ }
+
+#ifdef PNG_WRITE_16BIT_SUPPORTED
+ else
+ {
+ /* This converts from AAGG to GGAA */
+ png_bytep sp, dp;
+ png_uint_32 i;
+ png_uint_32 row_width = row_info->width;
+
+ for (i = 0, sp = dp = row; i < row_width; i++)
+ {
+ png_byte save[2];
+ save[0] = *(sp++);
+ save[1] = *(sp++);
+ *(dp++) = *(sp++);
+ *(dp++) = *(sp++);
+ *(dp++) = save[0];
+ *(dp++) = save[1];
+ }
+ }
+#endif /* WRITE_16BIT */
+ }
+ }
+}
+#endif
+
+#ifdef PNG_WRITE_INVERT_ALPHA_SUPPORTED
+static void
+png_do_write_invert_alpha(png_row_infop row_info, png_bytep row)
+{
+ png_debug(1, "in png_do_write_invert_alpha");
+
+ {
+ if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+ {
+ if (row_info->bit_depth == 8)
+ {
+ /* This inverts the alpha channel in RGBA */
+ png_bytep sp, dp;
+ png_uint_32 i;
+ png_uint_32 row_width = row_info->width;
+
+ for (i = 0, sp = dp = row; i < row_width; i++)
+ {
+ /* Does nothing
+ *(dp++) = *(sp++);
+ *(dp++) = *(sp++);
+ *(dp++) = *(sp++);
+ */
+ sp+=3; dp = sp;
+ *(dp++) = (png_byte)(255 - *(sp++));
+ }
+ }
+
+#ifdef PNG_WRITE_16BIT_SUPPORTED
+ else
+ {
+ /* This inverts the alpha channel in RRGGBBAA */
+ png_bytep sp, dp;
+ png_uint_32 i;
+ png_uint_32 row_width = row_info->width;
+
+ for (i = 0, sp = dp = row; i < row_width; i++)
+ {
+ /* Does nothing
+ *(dp++) = *(sp++);
+ *(dp++) = *(sp++);
+ *(dp++) = *(sp++);
+ *(dp++) = *(sp++);
+ *(dp++) = *(sp++);
+ *(dp++) = *(sp++);
+ */
+ sp+=6; dp = sp;
+ *(dp++) = (png_byte)(255 - *(sp++));
+ *(dp++) = (png_byte)(255 - *(sp++));
+ }
+ }
+#endif /* WRITE_16BIT */
+ }
+
+ else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
+ {
+ if (row_info->bit_depth == 8)
+ {
+ /* This inverts the alpha channel in GA */
+ png_bytep sp, dp;
+ png_uint_32 i;
+ png_uint_32 row_width = row_info->width;
+
+ for (i = 0, sp = dp = row; i < row_width; i++)
+ {
+ *(dp++) = *(sp++);
+ *(dp++) = (png_byte)(255 - *(sp++));
+ }
+ }
+
+#ifdef PNG_WRITE_16BIT_SUPPORTED
+ else
+ {
+ /* This inverts the alpha channel in GGAA */
+ png_bytep sp, dp;
+ png_uint_32 i;
+ png_uint_32 row_width = row_info->width;
+
+ for (i = 0, sp = dp = row; i < row_width; i++)
+ {
+ /* Does nothing
+ *(dp++) = *(sp++);
+ *(dp++) = *(sp++);
+ */
+ sp+=2; dp = sp;
+ *(dp++) = (png_byte)(255 - *(sp++));
+ *(dp++) = (png_byte)(255 - *(sp++));
+ }
+ }
+#endif /* WRITE_16BIT */
+ }
+ }
+}
+#endif
+
+/* Transform the data according to the user's wishes. The order of
+ * transformations is significant.
+ */
+void /* PRIVATE */
+png_do_write_transformations(png_structrp png_ptr, png_row_infop row_info)
+{
+ png_debug(1, "in png_do_write_transformations");
+
+ if (png_ptr == NULL)
+ return;
+
+#ifdef PNG_WRITE_USER_TRANSFORM_SUPPORTED
+ if ((png_ptr->transformations & PNG_USER_TRANSFORM) != 0)
+ if (png_ptr->write_user_transform_fn != NULL)
+ (*(png_ptr->write_user_transform_fn)) /* User write transform
+ function */
+ (png_ptr, /* png_ptr */
+ row_info, /* row_info: */
+ /* png_uint_32 width; width of row */
+ /* png_size_t rowbytes; number of bytes in row */
+ /* png_byte color_type; color type of pixels */
+ /* png_byte bit_depth; bit depth of samples */
+ /* png_byte channels; number of channels (1-4) */
+ /* png_byte pixel_depth; bits per pixel (depth*channels) */
+ png_ptr->row_buf + 1); /* start of pixel data for row */
+#endif
+
+#ifdef PNG_WRITE_FILLER_SUPPORTED
+ if ((png_ptr->transformations & PNG_FILLER) != 0)
+ png_do_strip_channel(row_info, png_ptr->row_buf + 1,
+ !(png_ptr->flags & PNG_FLAG_FILLER_AFTER));
+#endif
+
+#ifdef PNG_WRITE_PACKSWAP_SUPPORTED
+ if ((png_ptr->transformations & PNG_PACKSWAP) != 0)
+ png_do_packswap(row_info, png_ptr->row_buf + 1);
+#endif
+
+#ifdef PNG_WRITE_PACK_SUPPORTED
+ if ((png_ptr->transformations & PNG_PACK) != 0)
+ png_do_pack(row_info, png_ptr->row_buf + 1,
+ (png_uint_32)png_ptr->bit_depth);
+#endif
+
+#ifdef PNG_WRITE_SWAP_SUPPORTED
+# ifdef PNG_16BIT_SUPPORTED
+ if ((png_ptr->transformations & PNG_SWAP_BYTES) != 0)
+ png_do_swap(row_info, png_ptr->row_buf + 1);
+# endif
+#endif
+
+#ifdef PNG_WRITE_SHIFT_SUPPORTED
+ if ((png_ptr->transformations & PNG_SHIFT) != 0)
+ png_do_shift(row_info, png_ptr->row_buf + 1,
+ &(png_ptr->shift));
+#endif
+
+#ifdef PNG_WRITE_SWAP_ALPHA_SUPPORTED
+ if ((png_ptr->transformations & PNG_SWAP_ALPHA) != 0)
+ png_do_write_swap_alpha(row_info, png_ptr->row_buf + 1);
+#endif
+
+#ifdef PNG_WRITE_INVERT_ALPHA_SUPPORTED
+ if ((png_ptr->transformations & PNG_INVERT_ALPHA) != 0)
+ png_do_write_invert_alpha(row_info, png_ptr->row_buf + 1);
+#endif
+
+#ifdef PNG_WRITE_BGR_SUPPORTED
+ if ((png_ptr->transformations & PNG_BGR) != 0)
+ png_do_bgr(row_info, png_ptr->row_buf + 1);
+#endif
+
+#ifdef PNG_WRITE_INVERT_SUPPORTED
+ if ((png_ptr->transformations & PNG_INVERT_MONO) != 0)
+ png_do_invert(row_info, png_ptr->row_buf + 1);
+#endif
+}
+#endif /* WRITE_TRANSFORMS */
+#endif /* WRITE */
--- /dev/null
+
+/* pngwutil.c - utilities to write a PNG file
+ *
+ * Last changed in libpng 1.6.17 [March 26, 2015]
+ * Copyright (c) 1998-2015 Glenn Randers-Pehrson
+ * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
+ * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ */
+
+#include "pngpriv.h"
+
+#ifdef PNG_WRITE_SUPPORTED
+
+#ifdef PNG_WRITE_INT_FUNCTIONS_SUPPORTED
+/* Place a 32-bit number into a buffer in PNG byte order. We work
+ * with unsigned numbers for convenience, although one supported
+ * ancillary chunk uses signed (two's complement) numbers.
+ */
+void PNGAPI
+png_save_uint_32(png_bytep buf, png_uint_32 i)
+{
+ buf[0] = (png_byte)(i >> 24);
+ buf[1] = (png_byte)(i >> 16);
+ buf[2] = (png_byte)(i >> 8);
+ buf[3] = (png_byte)(i );
+}
+
+/* Place a 16-bit number into a buffer in PNG byte order.
+ * The parameter is declared unsigned int, not png_uint_16,
+ * just to avoid potential problems on pre-ANSI C compilers.
+ */
+void PNGAPI
+png_save_uint_16(png_bytep buf, unsigned int i)
+{
+ buf[0] = (png_byte)(i >> 8);
+ buf[1] = (png_byte)(i );
+}
+#endif
+
+/* Simple function to write the signature. If we have already written
+ * the magic bytes of the signature, or more likely, the PNG stream is
+ * being embedded into another stream and doesn't need its own signature,
+ * we should call png_set_sig_bytes() to tell libpng how many of the
+ * bytes have already been written.
+ */
+void PNGAPI
+png_write_sig(png_structrp png_ptr)
+{
+ png_byte png_signature[8] = {137, 80, 78, 71, 13, 10, 26, 10};
+
+#ifdef PNG_IO_STATE_SUPPORTED
+ /* Inform the I/O callback that the signature is being written */
+ png_ptr->io_state = PNG_IO_WRITING | PNG_IO_SIGNATURE;
+#endif
+
+ /* Write the rest of the 8 byte signature */
+ png_write_data(png_ptr, &png_signature[png_ptr->sig_bytes],
+ (png_size_t)(8 - png_ptr->sig_bytes));
+
+ if (png_ptr->sig_bytes < 3)
+ png_ptr->mode |= PNG_HAVE_PNG_SIGNATURE;
+}
+
+/* Write the start of a PNG chunk. The type is the chunk type.
+ * The total_length is the sum of the lengths of all the data you will be
+ * passing in png_write_chunk_data().
+ */
+static void
+png_write_chunk_header(png_structrp png_ptr, png_uint_32 chunk_name,
+ png_uint_32 length)
+{
+ png_byte buf[8];
+
+#if defined(PNG_DEBUG) && (PNG_DEBUG > 0)
+ PNG_CSTRING_FROM_CHUNK(buf, chunk_name);
+ png_debug2(0, "Writing %s chunk, length = %lu", buf, (unsigned long)length);
+#endif
+
+ if (png_ptr == NULL)
+ return;
+
+#ifdef PNG_IO_STATE_SUPPORTED
+ /* Inform the I/O callback that the chunk header is being written.
+ * PNG_IO_CHUNK_HDR requires a single I/O call.
+ */
+ png_ptr->io_state = PNG_IO_WRITING | PNG_IO_CHUNK_HDR;
+#endif
+
+ /* Write the length and the chunk name */
+ png_save_uint_32(buf, length);
+ png_save_uint_32(buf + 4, chunk_name);
+ png_write_data(png_ptr, buf, 8);
+
+ /* Put the chunk name into png_ptr->chunk_name */
+ png_ptr->chunk_name = chunk_name;
+
+ /* Reset the crc and run it over the chunk name */
+ png_reset_crc(png_ptr);
+
+ png_calculate_crc(png_ptr, buf + 4, 4);
+
+#ifdef PNG_IO_STATE_SUPPORTED
+ /* Inform the I/O callback that chunk data will (possibly) be written.
+ * PNG_IO_CHUNK_DATA does NOT require a specific number of I/O calls.
+ */
+ png_ptr->io_state = PNG_IO_WRITING | PNG_IO_CHUNK_DATA;
+#endif
+}
+
+void PNGAPI
+png_write_chunk_start(png_structrp png_ptr, png_const_bytep chunk_string,
+ png_uint_32 length)
+{
+ png_write_chunk_header(png_ptr, PNG_CHUNK_FROM_STRING(chunk_string), length);
+}
+
+/* Write the data of a PNG chunk started with png_write_chunk_header().
+ * Note that multiple calls to this function are allowed, and that the
+ * sum of the lengths from these calls *must* add up to the total_length
+ * given to png_write_chunk_header().
+ */
+void PNGAPI
+png_write_chunk_data(png_structrp png_ptr, png_const_bytep data,
+ png_size_t length)
+{
+ /* Write the data, and run the CRC over it */
+ if (png_ptr == NULL)
+ return;
+
+ if (data != NULL && length > 0)
+ {
+ png_write_data(png_ptr, data, length);
+
+ /* Update the CRC after writing the data,
+ * in case the user I/O routine alters it.
+ */
+ png_calculate_crc(png_ptr, data, length);
+ }
+}
+
+/* Finish a chunk started with png_write_chunk_header(). */
+void PNGAPI
+png_write_chunk_end(png_structrp png_ptr)
+{
+ png_byte buf[4];
+
+ if (png_ptr == NULL) return;
+
+#ifdef PNG_IO_STATE_SUPPORTED
+ /* Inform the I/O callback that the chunk CRC is being written.
+ * PNG_IO_CHUNK_CRC requires a single I/O function call.
+ */
+ png_ptr->io_state = PNG_IO_WRITING | PNG_IO_CHUNK_CRC;
+#endif
+
+ /* Write the crc in a single operation */
+ png_save_uint_32(buf, png_ptr->crc);
+
+ png_write_data(png_ptr, buf, (png_size_t)4);
+}
+
+/* Write a PNG chunk all at once. The type is an array of ASCII characters
+ * representing the chunk name. The array must be at least 4 bytes in
+ * length, and does not need to be null terminated. To be safe, pass the
+ * pre-defined chunk names here, and if you need a new one, define it
+ * where the others are defined. The length is the length of the data.
+ * All the data must be present. If that is not possible, use the
+ * png_write_chunk_start(), png_write_chunk_data(), and png_write_chunk_end()
+ * functions instead.
+ */
+static void
+png_write_complete_chunk(png_structrp png_ptr, png_uint_32 chunk_name,
+ png_const_bytep data, png_size_t length)
+{
+ if (png_ptr == NULL)
+ return;
+
+ /* On 64 bit architectures 'length' may not fit in a png_uint_32. */
+ if (length > PNG_UINT_31_MAX)
+ png_error(png_ptr, "length exceeds PNG maximum");
+
+ png_write_chunk_header(png_ptr, chunk_name, (png_uint_32)length);
+ png_write_chunk_data(png_ptr, data, length);
+ png_write_chunk_end(png_ptr);
+}
+
+/* This is the API that calls the internal function above. */
+void PNGAPI
+png_write_chunk(png_structrp png_ptr, png_const_bytep chunk_string,
+ png_const_bytep data, png_size_t length)
+{
+ png_write_complete_chunk(png_ptr, PNG_CHUNK_FROM_STRING(chunk_string), data,
+ length);
+}
+
+/* This is used below to find the size of an image to pass to png_deflate_claim,
+ * so it only needs to be accurate if the size is less than 16384 bytes (the
+ * point at which a lower LZ window size can be used.)
+ */
+static png_alloc_size_t
+png_image_size(png_structrp png_ptr)
+{
+ /* Only return sizes up to the maximum of a png_uint_32; do this by limiting
+ * the width and height used to 15 bits.
+ */
+ png_uint_32 h = png_ptr->height;
+
+ if (png_ptr->rowbytes < 32768 && h < 32768)
+ {
+ if (png_ptr->interlaced != 0)
+ {
+ /* Interlacing makes the image larger because of the replication of
+ * both the filter byte and the padding to a byte boundary.
+ */
+ png_uint_32 w = png_ptr->width;
+ unsigned int pd = png_ptr->pixel_depth;
+ png_alloc_size_t cb_base;
+ int pass;
+
+ for (cb_base=0, pass=0; pass<=6; ++pass)
+ {
+ png_uint_32 pw = PNG_PASS_COLS(w, pass);
+
+ if (pw > 0)
+ cb_base += (PNG_ROWBYTES(pd, pw)+1) * PNG_PASS_ROWS(h, pass);
+ }
+
+ return cb_base;
+ }
+
+ else
+ return (png_ptr->rowbytes+1) * h;
+ }
+
+ else
+ return 0xffffffffU;
+}
+
+#ifdef PNG_WRITE_OPTIMIZE_CMF_SUPPORTED
+ /* This is the code to hack the first two bytes of the deflate stream (the
+ * deflate header) to correct the windowBits value to match the actual data
+ * size. Note that the second argument is the *uncompressed* size but the
+ * first argument is the *compressed* data (and it must be deflate
+ * compressed.)
+ */
+static void
+optimize_cmf(png_bytep data, png_alloc_size_t data_size)
+{
+ /* Optimize the CMF field in the zlib stream. The resultant zlib stream is
+ * still compliant to the stream specification.
+ */
+ if (data_size <= 16384) /* else windowBits must be 15 */
+ {
+ unsigned int z_cmf = data[0]; /* zlib compression method and flags */
+
+ if ((z_cmf & 0x0f) == 8 && (z_cmf & 0xf0) <= 0x70)
+ {
+ unsigned int z_cinfo;
+ unsigned int half_z_window_size;
+
+ z_cinfo = z_cmf >> 4;
+ half_z_window_size = 1U << (z_cinfo + 7);
+
+ if (data_size <= half_z_window_size) /* else no change */
+ {
+ unsigned int tmp;
+
+ do
+ {
+ half_z_window_size >>= 1;
+ --z_cinfo;
+ }
+ while (z_cinfo > 0 && data_size <= half_z_window_size);
+
+ z_cmf = (z_cmf & 0x0f) | (z_cinfo << 4);
+
+ data[0] = (png_byte)z_cmf;
+ tmp = data[1] & 0xe0;
+ tmp += 0x1f - ((z_cmf << 8) + tmp) % 0x1f;
+ data[1] = (png_byte)tmp;
+ }
+ }
+ }
+}
+#endif /* WRITE_OPTIMIZE_CMF */
+
+/* Initialize the compressor for the appropriate type of compression. */
+static int
+png_deflate_claim(png_structrp png_ptr, png_uint_32 owner,
+ png_alloc_size_t data_size)
+{
+ if (png_ptr->zowner != 0)
+ {
+#if defined(PNG_WARNINGS_SUPPORTED) || defined(PNG_ERROR_TEXT_SUPPORTED)
+ char msg[64];
+
+ PNG_STRING_FROM_CHUNK(msg, owner);
+ msg[4] = ':';
+ msg[5] = ' ';
+ PNG_STRING_FROM_CHUNK(msg+6, png_ptr->zowner);
+ /* So the message that results is "<chunk> using zstream"; this is an
+ * internal error, but is very useful for debugging. i18n requirements
+ * are minimal.
+ */
+ (void)png_safecat(msg, (sizeof msg), 10, " using zstream");
+#endif
+#if PNG_LIBPNG_BUILD_BASE_TYPE >= PNG_LIBPNG_BUILD_RC
+ png_warning(png_ptr, msg);
+
+ /* Attempt sane error recovery */
+ if (png_ptr->zowner == png_IDAT) /* don't steal from IDAT */
+ {
+ png_ptr->zstream.msg = PNGZ_MSG_CAST("in use by IDAT");
+ return Z_STREAM_ERROR;
+ }
+
+ png_ptr->zowner = 0;
+#else
+ png_error(png_ptr, msg);
+#endif
+ }
+
+ {
+ int level = png_ptr->zlib_level;
+ int method = png_ptr->zlib_method;
+ int windowBits = png_ptr->zlib_window_bits;
+ int memLevel = png_ptr->zlib_mem_level;
+ int strategy; /* set below */
+ int ret; /* zlib return code */
+
+ if (owner == png_IDAT)
+ {
+ if ((png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_STRATEGY) != 0)
+ strategy = png_ptr->zlib_strategy;
+
+ else if (png_ptr->do_filter != PNG_FILTER_NONE)
+ strategy = PNG_Z_DEFAULT_STRATEGY;
+
+ else
+ strategy = PNG_Z_DEFAULT_NOFILTER_STRATEGY;
+ }
+
+ else
+ {
+#ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED
+ level = png_ptr->zlib_text_level;
+ method = png_ptr->zlib_text_method;
+ windowBits = png_ptr->zlib_text_window_bits;
+ memLevel = png_ptr->zlib_text_mem_level;
+ strategy = png_ptr->zlib_text_strategy;
+#else
+ /* If customization is not supported the values all come from the
+ * IDAT values except for the strategy, which is fixed to the
+ * default. (This is the pre-1.6.0 behavior too, although it was
+ * implemented in a very different way.)
+ */
+ strategy = Z_DEFAULT_STRATEGY;
+#endif
+ }
+
+ /* Adjust 'windowBits' down if larger than 'data_size'; to stop this
+ * happening just pass 32768 as the data_size parameter. Notice that zlib
+ * requires an extra 262 bytes in the window in addition to the data to be
+ * able to see the whole of the data, so if data_size+262 takes us to the
+ * next windowBits size we need to fix up the value later. (Because even
+ * though deflate needs the extra window, inflate does not!)
+ */
+ if (data_size <= 16384)
+ {
+ /* IMPLEMENTATION NOTE: this 'half_window_size' stuff is only here to
+ * work round a Microsoft Visual C misbehavior which, contrary to C-90,
+ * widens the result of the following shift to 64-bits if (and,
+ * apparently, only if) it is used in a test.
+ */
+ unsigned int half_window_size = 1U << (windowBits-1);
+
+ while (data_size + 262 <= half_window_size)
+ {
+ half_window_size >>= 1;
+ --windowBits;
+ }
+ }
+
+ /* Check against the previous initialized values, if any. */
+ if ((png_ptr->flags & PNG_FLAG_ZSTREAM_INITIALIZED) != 0 &&
+ (png_ptr->zlib_set_level != level ||
+ png_ptr->zlib_set_method != method ||
+ png_ptr->zlib_set_window_bits != windowBits ||
+ png_ptr->zlib_set_mem_level != memLevel ||
+ png_ptr->zlib_set_strategy != strategy))
+ {
+ if (deflateEnd(&png_ptr->zstream) != Z_OK)
+ png_warning(png_ptr, "deflateEnd failed (ignored)");
+
+ png_ptr->flags &= ~PNG_FLAG_ZSTREAM_INITIALIZED;
+ }
+
+ /* For safety clear out the input and output pointers (currently zlib
+ * doesn't use them on Init, but it might in the future).
+ */
+ png_ptr->zstream.next_in = NULL;
+ png_ptr->zstream.avail_in = 0;
+ png_ptr->zstream.next_out = NULL;
+ png_ptr->zstream.avail_out = 0;
+
+ /* Now initialize if required, setting the new parameters, otherwise just
+ * to a simple reset to the previous parameters.
+ */
+ if ((png_ptr->flags & PNG_FLAG_ZSTREAM_INITIALIZED) != 0)
+ ret = deflateReset(&png_ptr->zstream);
+
+ else
+ {
+ ret = deflateInit2(&png_ptr->zstream, level, method, windowBits,
+ memLevel, strategy);
+
+ if (ret == Z_OK)
+ png_ptr->flags |= PNG_FLAG_ZSTREAM_INITIALIZED;
+ }
+
+ /* The return code is from either deflateReset or deflateInit2; they have
+ * pretty much the same set of error codes.
+ */
+ if (ret == Z_OK)
+ png_ptr->zowner = owner;
+
+ else
+ png_zstream_error(png_ptr, ret);
+
+ return ret;
+ }
+}
+
+/* Clean up (or trim) a linked list of compression buffers. */
+void /* PRIVATE */
+png_free_buffer_list(png_structrp png_ptr, png_compression_bufferp *listp)
+{
+ png_compression_bufferp list = *listp;
+
+ if (list != NULL)
+ {
+ *listp = NULL;
+
+ do
+ {
+ png_compression_bufferp next = list->next;
+
+ png_free(png_ptr, list);
+ list = next;
+ }
+ while (list != NULL);
+ }
+}
+
+#ifdef PNG_WRITE_COMPRESSED_TEXT_SUPPORTED
+/* This pair of functions encapsulates the operation of (a) compressing a
+ * text string, and (b) issuing it later as a series of chunk data writes.
+ * The compression_state structure is shared context for these functions
+ * set up by the caller to allow access to the relevant local variables.
+ *
+ * compression_buffer (new in 1.6.0) is just a linked list of zbuffer_size
+ * temporary buffers. From 1.6.0 it is retained in png_struct so that it will
+ * be correctly freed in the event of a write error (previous implementations
+ * just leaked memory.)
+ */
+typedef struct
+{
+ png_const_bytep input; /* The uncompressed input data */
+ png_alloc_size_t input_len; /* Its length */
+ png_uint_32 output_len; /* Final compressed length */
+ png_byte output[1024]; /* First block of output */
+} compression_state;
+
+static void
+png_text_compress_init(compression_state *comp, png_const_bytep input,
+ png_alloc_size_t input_len)
+{
+ comp->input = input;
+ comp->input_len = input_len;
+ comp->output_len = 0;
+}
+
+/* Compress the data in the compression state input */
+static int
+png_text_compress(png_structrp png_ptr, png_uint_32 chunk_name,
+ compression_state *comp, png_uint_32 prefix_len)
+{
+ int ret;
+
+ /* To find the length of the output it is necessary to first compress the
+ * input. The result is buffered rather than using the two-pass algorithm
+ * that is used on the inflate side; deflate is assumed to be slower and a
+ * PNG writer is assumed to have more memory available than a PNG reader.
+ *
+ * IMPLEMENTATION NOTE: the zlib API deflateBound() can be used to find an
+ * upper limit on the output size, but it is always bigger than the input
+ * size so it is likely to be more efficient to use this linked-list
+ * approach.
+ */
+ ret = png_deflate_claim(png_ptr, chunk_name, comp->input_len);
+
+ if (ret != Z_OK)
+ return ret;
+
+ /* Set up the compression buffers, we need a loop here to avoid overflowing a
+ * uInt. Use ZLIB_IO_MAX to limit the input. The output is always limited
+ * by the output buffer size, so there is no need to check that. Since this
+ * is ANSI-C we know that an 'int', hence a uInt, is always at least 16 bits
+ * in size.
+ */
+ {
+ png_compression_bufferp *end = &png_ptr->zbuffer_list;
+ png_alloc_size_t input_len = comp->input_len; /* may be zero! */
+ png_uint_32 output_len;
+
+ /* zlib updates these for us: */
+ png_ptr->zstream.next_in = PNGZ_INPUT_CAST(comp->input);
+ png_ptr->zstream.avail_in = 0; /* Set below */
+ png_ptr->zstream.next_out = comp->output;
+ png_ptr->zstream.avail_out = (sizeof comp->output);
+
+ output_len = png_ptr->zstream.avail_out;
+
+ do
+ {
+ uInt avail_in = ZLIB_IO_MAX;
+
+ if (avail_in > input_len)
+ avail_in = (uInt)input_len;
+
+ input_len -= avail_in;
+
+ png_ptr->zstream.avail_in = avail_in;
+
+ if (png_ptr->zstream.avail_out == 0)
+ {
+ png_compression_buffer *next;
+
+ /* Chunk data is limited to 2^31 bytes in length, so the prefix
+ * length must be counted here.
+ */
+ if (output_len + prefix_len > PNG_UINT_31_MAX)
+ {
+ ret = Z_MEM_ERROR;
+ break;
+ }
+
+ /* Need a new (malloc'ed) buffer, but there may be one present
+ * already.
+ */
+ next = *end;
+ if (next == NULL)
+ {
+ next = png_voidcast(png_compression_bufferp, png_malloc_base
+ (png_ptr, PNG_COMPRESSION_BUFFER_SIZE(png_ptr)));
+
+ if (next == NULL)
+ {
+ ret = Z_MEM_ERROR;
+ break;
+ }
+
+ /* Link in this buffer (so that it will be freed later) */
+ next->next = NULL;
+ *end = next;
+ }
+
+ png_ptr->zstream.next_out = next->output;
+ png_ptr->zstream.avail_out = png_ptr->zbuffer_size;
+ output_len += png_ptr->zstream.avail_out;
+
+ /* Move 'end' to the next buffer pointer. */
+ end = &next->next;
+ }
+
+ /* Compress the data */
+ ret = deflate(&png_ptr->zstream,
+ input_len > 0 ? Z_NO_FLUSH : Z_FINISH);
+
+ /* Claw back input data that was not consumed (because avail_in is
+ * reset above every time round the loop).
+ */
+ input_len += png_ptr->zstream.avail_in;
+ png_ptr->zstream.avail_in = 0; /* safety */
+ }
+ while (ret == Z_OK);
+
+ /* There may be some space left in the last output buffer. This needs to
+ * be subtracted from output_len.
+ */
+ output_len -= png_ptr->zstream.avail_out;
+ png_ptr->zstream.avail_out = 0; /* safety */
+ comp->output_len = output_len;
+
+ /* Now double check the output length, put in a custom message if it is
+ * too long. Otherwise ensure the z_stream::msg pointer is set to
+ * something.
+ */
+ if (output_len + prefix_len >= PNG_UINT_31_MAX)
+ {
+ png_ptr->zstream.msg = PNGZ_MSG_CAST("compressed data too long");
+ ret = Z_MEM_ERROR;
+ }
+
+ else
+ png_zstream_error(png_ptr, ret);
+
+ /* Reset zlib for another zTXt/iTXt or image data */
+ png_ptr->zowner = 0;
+
+ /* The only success case is Z_STREAM_END, input_len must be 0; if not this
+ * is an internal error.
+ */
+ if (ret == Z_STREAM_END && input_len == 0)
+ {
+#ifdef PNG_WRITE_OPTIMIZE_CMF_SUPPORTED
+ /* Fix up the deflate header, if required */
+ optimize_cmf(comp->output, comp->input_len);
+#endif
+ /* But Z_OK is returned, not Z_STREAM_END; this allows the claim
+ * function above to return Z_STREAM_END on an error (though it never
+ * does in the current versions of zlib.)
+ */
+ return Z_OK;
+ }
+
+ else
+ return ret;
+ }
+}
+
+/* Ship the compressed text out via chunk writes */
+static void
+png_write_compressed_data_out(png_structrp png_ptr, compression_state *comp)
+{
+ png_uint_32 output_len = comp->output_len;
+ png_const_bytep output = comp->output;
+ png_uint_32 avail = (sizeof comp->output);
+ png_compression_buffer *next = png_ptr->zbuffer_list;
+
+ for (;;)
+ {
+ if (avail > output_len)
+ avail = output_len;
+
+ png_write_chunk_data(png_ptr, output, avail);
+
+ output_len -= avail;
+
+ if (output_len == 0 || next == NULL)
+ break;
+
+ avail = png_ptr->zbuffer_size;
+ output = next->output;
+ next = next->next;
+ }
+
+ /* This is an internal error; 'next' must have been NULL! */
+ if (output_len > 0)
+ png_error(png_ptr, "error writing ancillary chunked compressed data");
+}
+#endif /* WRITE_COMPRESSED_TEXT */
+
+#if defined(PNG_WRITE_TEXT_SUPPORTED) || defined(PNG_WRITE_pCAL_SUPPORTED) || \
+ defined(PNG_WRITE_iCCP_SUPPORTED) || defined(PNG_WRITE_sPLT_SUPPORTED)
+/* Check that the tEXt or zTXt keyword is valid per PNG 1.0 specification,
+ * and if invalid, correct the keyword rather than discarding the entire
+ * chunk. The PNG 1.0 specification requires keywords 1-79 characters in
+ * length, forbids leading or trailing whitespace, multiple internal spaces,
+ * and the non-break space (0x80) from ISO 8859-1. Returns keyword length.
+ *
+ * The 'new_key' buffer must be 80 characters in size (for the keyword plus a
+ * trailing '\0'). If this routine returns 0 then there was no keyword, or a
+ * valid one could not be generated, and the caller must png_error.
+ */
+static png_uint_32
+png_check_keyword(png_structrp png_ptr, png_const_charp key, png_bytep new_key)
+{
+ png_const_charp orig_key = key;
+ png_uint_32 key_len = 0;
+ int bad_character = 0;
+ int space = 1;
+
+ png_debug(1, "in png_check_keyword");
+
+ if (key == NULL)
+ {
+ *new_key = 0;
+ return 0;
+ }
+
+ while (*key && key_len < 79)
+ {
+ png_byte ch = (png_byte)*key++;
+
+ if ((ch > 32 && ch <= 126) || (ch >= 161 /*&& ch <= 255*/))
+ *new_key++ = ch, ++key_len, space = 0;
+
+ else if (space == 0)
+ {
+ /* A space or an invalid character when one wasn't seen immediately
+ * before; output just a space.
+ */
+ *new_key++ = 32, ++key_len, space = 1;
+
+ /* If the character was not a space then it is invalid. */
+ if (ch != 32)
+ bad_character = ch;
+ }
+
+ else if (bad_character == 0)
+ bad_character = ch; /* just skip it, record the first error */
+ }
+
+ if (key_len > 0 && space != 0) /* trailing space */
+ {
+ --key_len, --new_key;
+ if (bad_character == 0)
+ bad_character = 32;
+ }
+
+ /* Terminate the keyword */
+ *new_key = 0;
+
+ if (key_len == 0)
+ return 0;
+
+#ifdef PNG_WARNINGS_SUPPORTED
+ /* Try to only output one warning per keyword: */
+ if (*key != 0) /* keyword too long */
+ png_warning(png_ptr, "keyword truncated");
+
+ else if (bad_character != 0)
+ {
+ PNG_WARNING_PARAMETERS(p)
+
+ png_warning_parameter(p, 1, orig_key);
+ png_warning_parameter_signed(p, 2, PNG_NUMBER_FORMAT_02x, bad_character);
+
+ png_formatted_warning(png_ptr, p, "keyword \"@1\": bad character '0x@2'");
+ }
+#endif /* WARNINGS */
+
+ return key_len;
+}
+#endif /* WRITE_TEXT || WRITE_pCAL || WRITE_iCCP || WRITE_sPLT */
+
+/* Write the IHDR chunk, and update the png_struct with the necessary
+ * information. Note that the rest of this code depends upon this
+ * information being correct.
+ */
+void /* PRIVATE */
+png_write_IHDR(png_structrp png_ptr, png_uint_32 width, png_uint_32 height,
+ int bit_depth, int color_type, int compression_type, int filter_type,
+ int interlace_type)
+{
+ png_byte buf[13]; /* Buffer to store the IHDR info */
+
+ png_debug(1, "in png_write_IHDR");
+
+ /* Check that we have valid input data from the application info */
+ switch (color_type)
+ {
+ case PNG_COLOR_TYPE_GRAY:
+ switch (bit_depth)
+ {
+ case 1:
+ case 2:
+ case 4:
+ case 8:
+#ifdef PNG_WRITE_16BIT_SUPPORTED
+ case 16:
+#endif
+ png_ptr->channels = 1; break;
+
+ default:
+ png_error(png_ptr,
+ "Invalid bit depth for grayscale image");
+ }
+ break;
+
+ case PNG_COLOR_TYPE_RGB:
+#ifdef PNG_WRITE_16BIT_SUPPORTED
+ if (bit_depth != 8 && bit_depth != 16)
+#else
+ if (bit_depth != 8)
+#endif
+ png_error(png_ptr, "Invalid bit depth for RGB image");
+
+ png_ptr->channels = 3;
+ break;
+
+ case PNG_COLOR_TYPE_PALETTE:
+ switch (bit_depth)
+ {
+ case 1:
+ case 2:
+ case 4:
+ case 8:
+ png_ptr->channels = 1;
+ break;
+
+ default:
+ png_error(png_ptr, "Invalid bit depth for paletted image");
+ }
+ break;
+
+ case PNG_COLOR_TYPE_GRAY_ALPHA:
+ if (bit_depth != 8 && bit_depth != 16)
+ png_error(png_ptr, "Invalid bit depth for grayscale+alpha image");
+
+ png_ptr->channels = 2;
+ break;
+
+ case PNG_COLOR_TYPE_RGB_ALPHA:
+#ifdef PNG_WRITE_16BIT_SUPPORTED
+ if (bit_depth != 8 && bit_depth != 16)
+#else
+ if (bit_depth != 8)
+#endif
+ png_error(png_ptr, "Invalid bit depth for RGBA image");
+
+ png_ptr->channels = 4;
+ break;
+
+ default:
+ png_error(png_ptr, "Invalid image color type specified");
+ }
+
+ if (compression_type != PNG_COMPRESSION_TYPE_BASE)
+ {
+ png_warning(png_ptr, "Invalid compression type specified");
+ compression_type = PNG_COMPRESSION_TYPE_BASE;
+ }
+
+ /* Write filter_method 64 (intrapixel differencing) only if
+ * 1. Libpng was compiled with PNG_MNG_FEATURES_SUPPORTED and
+ * 2. Libpng did not write a PNG signature (this filter_method is only
+ * used in PNG datastreams that are embedded in MNG datastreams) and
+ * 3. The application called png_permit_mng_features with a mask that
+ * included PNG_FLAG_MNG_FILTER_64 and
+ * 4. The filter_method is 64 and
+ * 5. The color_type is RGB or RGBA
+ */
+ if (
+#ifdef PNG_MNG_FEATURES_SUPPORTED
+ !((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) != 0 &&
+ ((png_ptr->mode & PNG_HAVE_PNG_SIGNATURE) == 0) &&
+ (color_type == PNG_COLOR_TYPE_RGB ||
+ color_type == PNG_COLOR_TYPE_RGB_ALPHA) &&
+ (filter_type == PNG_INTRAPIXEL_DIFFERENCING)) &&
+#endif
+ filter_type != PNG_FILTER_TYPE_BASE)
+ {
+ png_warning(png_ptr, "Invalid filter type specified");
+ filter_type = PNG_FILTER_TYPE_BASE;
+ }
+
+#ifdef PNG_WRITE_INTERLACING_SUPPORTED
+ if (interlace_type != PNG_INTERLACE_NONE &&
+ interlace_type != PNG_INTERLACE_ADAM7)
+ {
+ png_warning(png_ptr, "Invalid interlace type specified");
+ interlace_type = PNG_INTERLACE_ADAM7;
+ }
+#else
+ interlace_type=PNG_INTERLACE_NONE;
+#endif
+
+ /* Save the relevant information */
+ png_ptr->bit_depth = (png_byte)bit_depth;
+ png_ptr->color_type = (png_byte)color_type;
+ png_ptr->interlaced = (png_byte)interlace_type;
+#ifdef PNG_MNG_FEATURES_SUPPORTED
+ png_ptr->filter_type = (png_byte)filter_type;
+#endif
+ png_ptr->compression_type = (png_byte)compression_type;
+ png_ptr->width = width;
+ png_ptr->height = height;
+
+ png_ptr->pixel_depth = (png_byte)(bit_depth * png_ptr->channels);
+ png_ptr->rowbytes = PNG_ROWBYTES(png_ptr->pixel_depth, width);
+ /* Set the usr info, so any transformations can modify it */
+ png_ptr->usr_width = png_ptr->width;
+ png_ptr->usr_bit_depth = png_ptr->bit_depth;
+ png_ptr->usr_channels = png_ptr->channels;
+
+ /* Pack the header information into the buffer */
+ png_save_uint_32(buf, width);
+ png_save_uint_32(buf + 4, height);
+ buf[8] = (png_byte)bit_depth;
+ buf[9] = (png_byte)color_type;
+ buf[10] = (png_byte)compression_type;
+ buf[11] = (png_byte)filter_type;
+ buf[12] = (png_byte)interlace_type;
+
+ /* Write the chunk */
+ png_write_complete_chunk(png_ptr, png_IHDR, buf, (png_size_t)13);
+
+ if ((png_ptr->do_filter) == PNG_NO_FILTERS)
+ {
+ if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE ||
+ png_ptr->bit_depth < 8)
+ png_ptr->do_filter = PNG_FILTER_NONE;
+
+ else
+ png_ptr->do_filter = PNG_ALL_FILTERS;
+ }
+
+ png_ptr->mode = PNG_HAVE_IHDR; /* not READY_FOR_ZTXT */
+}
+
+/* Write the palette. We are careful not to trust png_color to be in the
+ * correct order for PNG, so people can redefine it to any convenient
+ * structure.
+ */
+void /* PRIVATE */
+png_write_PLTE(png_structrp png_ptr, png_const_colorp palette,
+ png_uint_32 num_pal)
+{
+ png_uint_32 i;
+ png_const_colorp pal_ptr;
+ png_byte buf[3];
+
+ png_debug(1, "in png_write_PLTE");
+
+ if ((
+#ifdef PNG_MNG_FEATURES_SUPPORTED
+ (png_ptr->mng_features_permitted & PNG_FLAG_MNG_EMPTY_PLTE) == 0 &&
+#endif
+ num_pal == 0) || num_pal > 256)
+ {
+ if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
+ {
+ png_error(png_ptr, "Invalid number of colors in palette");
+ }
+
+ else
+ {
+ png_warning(png_ptr, "Invalid number of colors in palette");
+ return;
+ }
+ }
+
+ if ((png_ptr->color_type & PNG_COLOR_MASK_COLOR) == 0)
+ {
+ png_warning(png_ptr,
+ "Ignoring request to write a PLTE chunk in grayscale PNG");
+
+ return;
+ }
+
+ png_ptr->num_palette = (png_uint_16)num_pal;
+ png_debug1(3, "num_palette = %d", png_ptr->num_palette);
+
+ png_write_chunk_header(png_ptr, png_PLTE, (png_uint_32)(num_pal * 3));
+#ifdef PNG_POINTER_INDEXING_SUPPORTED
+
+ for (i = 0, pal_ptr = palette; i < num_pal; i++, pal_ptr++)
+ {
+ buf[0] = pal_ptr->red;
+ buf[1] = pal_ptr->green;
+ buf[2] = pal_ptr->blue;
+ png_write_chunk_data(png_ptr, buf, (png_size_t)3);
+ }
+
+#else
+ /* This is a little slower but some buggy compilers need to do this
+ * instead
+ */
+ pal_ptr=palette;
+
+ for (i = 0; i < num_pal; i++)
+ {
+ buf[0] = pal_ptr[i].red;
+ buf[1] = pal_ptr[i].green;
+ buf[2] = pal_ptr[i].blue;
+ png_write_chunk_data(png_ptr, buf, (png_size_t)3);
+ }
+
+#endif
+ png_write_chunk_end(png_ptr);
+ png_ptr->mode |= PNG_HAVE_PLTE;
+}
+
+/* This is similar to png_text_compress, above, except that it does not require
+ * all of the data at once and, instead of buffering the compressed result,
+ * writes it as IDAT chunks. Unlike png_text_compress it *can* png_error out
+ * because it calls the write interface. As a result it does its own error
+ * reporting and does not return an error code. In the event of error it will
+ * just call png_error. The input data length may exceed 32-bits. The 'flush'
+ * parameter is exactly the same as that to deflate, with the following
+ * meanings:
+ *
+ * Z_NO_FLUSH: normal incremental output of compressed data
+ * Z_SYNC_FLUSH: do a SYNC_FLUSH, used by png_write_flush
+ * Z_FINISH: this is the end of the input, do a Z_FINISH and clean up
+ *
+ * The routine manages the acquire and release of the png_ptr->zstream by
+ * checking and (at the end) clearing png_ptr->zowner; it does some sanity
+ * checks on the 'mode' flags while doing this.
+ */
+void /* PRIVATE */
+png_compress_IDAT(png_structrp png_ptr, png_const_bytep input,
+ png_alloc_size_t input_len, int flush)
+{
+ if (png_ptr->zowner != png_IDAT)
+ {
+ /* First time. Ensure we have a temporary buffer for compression and
+ * trim the buffer list if it has more than one entry to free memory.
+ * If 'WRITE_COMPRESSED_TEXT' is not set the list will never have been
+ * created at this point, but the check here is quick and safe.
+ */
+ if (png_ptr->zbuffer_list == NULL)
+ {
+ png_ptr->zbuffer_list = png_voidcast(png_compression_bufferp,
+ png_malloc(png_ptr, PNG_COMPRESSION_BUFFER_SIZE(png_ptr)));
+ png_ptr->zbuffer_list->next = NULL;
+ }
+
+ else
+ png_free_buffer_list(png_ptr, &png_ptr->zbuffer_list->next);
+
+ /* It is a terminal error if we can't claim the zstream. */
+ if (png_deflate_claim(png_ptr, png_IDAT, png_image_size(png_ptr)) != Z_OK)
+ png_error(png_ptr, png_ptr->zstream.msg);
+
+ /* The output state is maintained in png_ptr->zstream, so it must be
+ * initialized here after the claim.
+ */
+ png_ptr->zstream.next_out = png_ptr->zbuffer_list->output;
+ png_ptr->zstream.avail_out = png_ptr->zbuffer_size;
+ }
+
+ /* Now loop reading and writing until all the input is consumed or an error
+ * terminates the operation. The _out values are maintained across calls to
+ * this function, but the input must be reset each time.
+ */
+ png_ptr->zstream.next_in = PNGZ_INPUT_CAST(input);
+ png_ptr->zstream.avail_in = 0; /* set below */
+ for (;;)
+ {
+ int ret;
+
+ /* INPUT: from the row data */
+ uInt avail = ZLIB_IO_MAX;
+
+ if (avail > input_len)
+ avail = (uInt)input_len; /* safe because of the check */
+
+ png_ptr->zstream.avail_in = avail;
+ input_len -= avail;
+
+ ret = deflate(&png_ptr->zstream, input_len > 0 ? Z_NO_FLUSH : flush);
+
+ /* Include as-yet unconsumed input */
+ input_len += png_ptr->zstream.avail_in;
+ png_ptr->zstream.avail_in = 0;
+
+ /* OUTPUT: write complete IDAT chunks when avail_out drops to zero. Note
+ * that these two zstream fields are preserved across the calls, therefore
+ * there is no need to set these up on entry to the loop.
+ */
+ if (png_ptr->zstream.avail_out == 0)
+ {
+ png_bytep data = png_ptr->zbuffer_list->output;
+ uInt size = png_ptr->zbuffer_size;
+
+ /* Write an IDAT containing the data then reset the buffer. The
+ * first IDAT may need deflate header optimization.
+ */
+#ifdef PNG_WRITE_OPTIMIZE_CMF_SUPPORTED
+ if ((png_ptr->mode & PNG_HAVE_IDAT) == 0 &&
+ png_ptr->compression_type == PNG_COMPRESSION_TYPE_BASE)
+ optimize_cmf(data, png_image_size(png_ptr));
+#endif
+
+ png_write_complete_chunk(png_ptr, png_IDAT, data, size);
+ png_ptr->mode |= PNG_HAVE_IDAT;
+
+ png_ptr->zstream.next_out = data;
+ png_ptr->zstream.avail_out = size;
+
+ /* For SYNC_FLUSH or FINISH it is essential to keep calling zlib with
+ * the same flush parameter until it has finished output, for NO_FLUSH
+ * it doesn't matter.
+ */
+ if (ret == Z_OK && flush != Z_NO_FLUSH)
+ continue;
+ }
+
+ /* The order of these checks doesn't matter much; it just affects which
+ * possible error might be detected if multiple things go wrong at once.
+ */
+ if (ret == Z_OK) /* most likely return code! */
+ {
+ /* If all the input has been consumed then just return. If Z_FINISH
+ * was used as the flush parameter something has gone wrong if we get
+ * here.
+ */
+ if (input_len == 0)
+ {
+ if (flush == Z_FINISH)
+ png_error(png_ptr, "Z_OK on Z_FINISH with output space");
+
+ return;
+ }
+ }
+
+ else if (ret == Z_STREAM_END && flush == Z_FINISH)
+ {
+ /* This is the end of the IDAT data; any pending output must be
+ * flushed. For small PNG files we may still be at the beginning.
+ */
+ png_bytep data = png_ptr->zbuffer_list->output;
+ uInt size = png_ptr->zbuffer_size - png_ptr->zstream.avail_out;
+
+#ifdef PNG_WRITE_OPTIMIZE_CMF_SUPPORTED
+ if ((png_ptr->mode & PNG_HAVE_IDAT) == 0 &&
+ png_ptr->compression_type == PNG_COMPRESSION_TYPE_BASE)
+ optimize_cmf(data, png_image_size(png_ptr));
+#endif
+
+ png_write_complete_chunk(png_ptr, png_IDAT, data, size);
+ png_ptr->zstream.avail_out = 0;
+ png_ptr->zstream.next_out = NULL;
+ png_ptr->mode |= PNG_HAVE_IDAT | PNG_AFTER_IDAT;
+
+ png_ptr->zowner = 0; /* Release the stream */
+ return;
+ }
+
+ else
+ {
+ /* This is an error condition. */
+ png_zstream_error(png_ptr, ret);
+ png_error(png_ptr, png_ptr->zstream.msg);
+ }
+ }
+}
+
+/* Write an IEND chunk */
+void /* PRIVATE */
+png_write_IEND(png_structrp png_ptr)
+{
+ png_debug(1, "in png_write_IEND");
+
+ png_write_complete_chunk(png_ptr, png_IEND, NULL, (png_size_t)0);
+ png_ptr->mode |= PNG_HAVE_IEND;
+}
+
+#ifdef PNG_WRITE_gAMA_SUPPORTED
+/* Write a gAMA chunk */
+void /* PRIVATE */
+png_write_gAMA_fixed(png_structrp png_ptr, png_fixed_point file_gamma)
+{
+ png_byte buf[4];
+
+ png_debug(1, "in png_write_gAMA");
+
+ /* file_gamma is saved in 1/100,000ths */
+ png_save_uint_32(buf, (png_uint_32)file_gamma);
+ png_write_complete_chunk(png_ptr, png_gAMA, buf, (png_size_t)4);
+}
+#endif
+
+#ifdef PNG_WRITE_sRGB_SUPPORTED
+/* Write a sRGB chunk */
+void /* PRIVATE */
+png_write_sRGB(png_structrp png_ptr, int srgb_intent)
+{
+ png_byte buf[1];
+
+ png_debug(1, "in png_write_sRGB");
+
+ if (srgb_intent >= PNG_sRGB_INTENT_LAST)
+ png_warning(png_ptr,
+ "Invalid sRGB rendering intent specified");
+
+ buf[0]=(png_byte)srgb_intent;
+ png_write_complete_chunk(png_ptr, png_sRGB, buf, (png_size_t)1);
+}
+#endif
+
+#ifdef PNG_WRITE_iCCP_SUPPORTED
+/* Write an iCCP chunk */
+void /* PRIVATE */
+png_write_iCCP(png_structrp png_ptr, png_const_charp name,
+ png_const_bytep profile)
+{
+ png_uint_32 name_len;
+ png_uint_32 profile_len;
+ png_byte new_name[81]; /* 1 byte for the compression byte */
+ compression_state comp;
+ png_uint_32 temp;
+
+ png_debug(1, "in png_write_iCCP");
+
+ /* These are all internal problems: the profile should have been checked
+ * before when it was stored.
+ */
+ if (profile == NULL)
+ png_error(png_ptr, "No profile for iCCP chunk"); /* internal error */
+
+ profile_len = png_get_uint_32(profile);
+
+ if (profile_len < 132)
+ png_error(png_ptr, "ICC profile too short");
+
+ temp = (png_uint_32) (*(profile+8));
+ if (temp > 3 && (profile_len & 0x03))
+ png_error(png_ptr, "ICC profile length invalid (not a multiple of 4)");
+
+ {
+ png_uint_32 embedded_profile_len = png_get_uint_32(profile);
+
+ if (profile_len != embedded_profile_len)
+ png_error(png_ptr, "Profile length does not match profile");
+ }
+
+ name_len = png_check_keyword(png_ptr, name, new_name);
+
+ if (name_len == 0)
+ png_error(png_ptr, "iCCP: invalid keyword");
+
+ new_name[++name_len] = PNG_COMPRESSION_TYPE_BASE;
+
+ /* Make sure we include the NULL after the name and the compression type */
+ ++name_len;
+
+ png_text_compress_init(&comp, profile, profile_len);
+
+ /* Allow for keyword terminator and compression byte */
+ if (png_text_compress(png_ptr, png_iCCP, &comp, name_len) != Z_OK)
+ png_error(png_ptr, png_ptr->zstream.msg);
+
+ png_write_chunk_header(png_ptr, png_iCCP, name_len + comp.output_len);
+
+ png_write_chunk_data(png_ptr, new_name, name_len);
+
+ png_write_compressed_data_out(png_ptr, &comp);
+
+ png_write_chunk_end(png_ptr);
+}
+#endif
+
+#ifdef PNG_WRITE_sPLT_SUPPORTED
+/* Write a sPLT chunk */
+void /* PRIVATE */
+png_write_sPLT(png_structrp png_ptr, png_const_sPLT_tp spalette)
+{
+ png_uint_32 name_len;
+ png_byte new_name[80];
+ png_byte entrybuf[10];
+ png_size_t entry_size = (spalette->depth == 8 ? 6 : 10);
+ png_size_t palette_size = entry_size * spalette->nentries;
+ png_sPLT_entryp ep;
+#ifndef PNG_POINTER_INDEXING_SUPPORTED
+ int i;
+#endif
+
+ png_debug(1, "in png_write_sPLT");
+
+ name_len = png_check_keyword(png_ptr, spalette->name, new_name);
+
+ if (name_len == 0)
+ png_error(png_ptr, "sPLT: invalid keyword");
+
+ /* Make sure we include the NULL after the name */
+ png_write_chunk_header(png_ptr, png_sPLT,
+ (png_uint_32)(name_len + 2 + palette_size));
+
+ png_write_chunk_data(png_ptr, (png_bytep)new_name,
+ (png_size_t)(name_len + 1));
+
+ png_write_chunk_data(png_ptr, &spalette->depth, (png_size_t)1);
+
+ /* Loop through each palette entry, writing appropriately */
+#ifdef PNG_POINTER_INDEXING_SUPPORTED
+ for (ep = spalette->entries; ep<spalette->entries + spalette->nentries; ep++)
+ {
+ if (spalette->depth == 8)
+ {
+ entrybuf[0] = (png_byte)ep->red;
+ entrybuf[1] = (png_byte)ep->green;
+ entrybuf[2] = (png_byte)ep->blue;
+ entrybuf[3] = (png_byte)ep->alpha;
+ png_save_uint_16(entrybuf + 4, ep->frequency);
+ }
+
+ else
+ {
+ png_save_uint_16(entrybuf + 0, ep->red);
+ png_save_uint_16(entrybuf + 2, ep->green);
+ png_save_uint_16(entrybuf + 4, ep->blue);
+ png_save_uint_16(entrybuf + 6, ep->alpha);
+ png_save_uint_16(entrybuf + 8, ep->frequency);
+ }
+
+ png_write_chunk_data(png_ptr, entrybuf, entry_size);
+ }
+#else
+ ep=spalette->entries;
+ for (i = 0; i>spalette->nentries; i++)
+ {
+ if (spalette->depth == 8)
+ {
+ entrybuf[0] = (png_byte)ep[i].red;
+ entrybuf[1] = (png_byte)ep[i].green;
+ entrybuf[2] = (png_byte)ep[i].blue;
+ entrybuf[3] = (png_byte)ep[i].alpha;
+ png_save_uint_16(entrybuf + 4, ep[i].frequency);
+ }
+
+ else
+ {
+ png_save_uint_16(entrybuf + 0, ep[i].red);
+ png_save_uint_16(entrybuf + 2, ep[i].green);
+ png_save_uint_16(entrybuf + 4, ep[i].blue);
+ png_save_uint_16(entrybuf + 6, ep[i].alpha);
+ png_save_uint_16(entrybuf + 8, ep[i].frequency);
+ }
+
+ png_write_chunk_data(png_ptr, entrybuf, entry_size);
+ }
+#endif
+
+ png_write_chunk_end(png_ptr);
+}
+#endif
+
+#ifdef PNG_WRITE_sBIT_SUPPORTED
+/* Write the sBIT chunk */
+void /* PRIVATE */
+png_write_sBIT(png_structrp png_ptr, png_const_color_8p sbit, int color_type)
+{
+ png_byte buf[4];
+ png_size_t size;
+
+ png_debug(1, "in png_write_sBIT");
+
+ /* Make sure we don't depend upon the order of PNG_COLOR_8 */
+ if ((color_type & PNG_COLOR_MASK_COLOR) != 0)
+ {
+ png_byte maxbits;
+
+ maxbits = (png_byte)(color_type==PNG_COLOR_TYPE_PALETTE ? 8 :
+ png_ptr->usr_bit_depth);
+
+ if (sbit->red == 0 || sbit->red > maxbits ||
+ sbit->green == 0 || sbit->green > maxbits ||
+ sbit->blue == 0 || sbit->blue > maxbits)
+ {
+ png_warning(png_ptr, "Invalid sBIT depth specified");
+ return;
+ }
+
+ buf[0] = sbit->red;
+ buf[1] = sbit->green;
+ buf[2] = sbit->blue;
+ size = 3;
+ }
+
+ else
+ {
+ if (sbit->gray == 0 || sbit->gray > png_ptr->usr_bit_depth)
+ {
+ png_warning(png_ptr, "Invalid sBIT depth specified");
+ return;
+ }
+
+ buf[0] = sbit->gray;
+ size = 1;
+ }
+
+ if ((color_type & PNG_COLOR_MASK_ALPHA) != 0)
+ {
+ if (sbit->alpha == 0 || sbit->alpha > png_ptr->usr_bit_depth)
+ {
+ png_warning(png_ptr, "Invalid sBIT depth specified");
+ return;
+ }
+
+ buf[size++] = sbit->alpha;
+ }
+
+ png_write_complete_chunk(png_ptr, png_sBIT, buf, size);
+}
+#endif
+
+#ifdef PNG_WRITE_cHRM_SUPPORTED
+/* Write the cHRM chunk */
+void /* PRIVATE */
+png_write_cHRM_fixed(png_structrp png_ptr, const png_xy *xy)
+{
+ png_byte buf[32];
+
+ png_debug(1, "in png_write_cHRM");
+
+ /* Each value is saved in 1/100,000ths */
+ png_save_int_32(buf, xy->whitex);
+ png_save_int_32(buf + 4, xy->whitey);
+
+ png_save_int_32(buf + 8, xy->redx);
+ png_save_int_32(buf + 12, xy->redy);
+
+ png_save_int_32(buf + 16, xy->greenx);
+ png_save_int_32(buf + 20, xy->greeny);
+
+ png_save_int_32(buf + 24, xy->bluex);
+ png_save_int_32(buf + 28, xy->bluey);
+
+ png_write_complete_chunk(png_ptr, png_cHRM, buf, 32);
+}
+#endif
+
+#ifdef PNG_WRITE_tRNS_SUPPORTED
+/* Write the tRNS chunk */
+void /* PRIVATE */
+png_write_tRNS(png_structrp png_ptr, png_const_bytep trans_alpha,
+ png_const_color_16p tran, int num_trans, int color_type)
+{
+ png_byte buf[6];
+
+ png_debug(1, "in png_write_tRNS");
+
+ if (color_type == PNG_COLOR_TYPE_PALETTE)
+ {
+ if (num_trans <= 0 || num_trans > (int)png_ptr->num_palette)
+ {
+ png_app_warning(png_ptr,
+ "Invalid number of transparent colors specified");
+ return;
+ }
+
+ /* Write the chunk out as it is */
+ png_write_complete_chunk(png_ptr, png_tRNS, trans_alpha,
+ (png_size_t)num_trans);
+ }
+
+ else if (color_type == PNG_COLOR_TYPE_GRAY)
+ {
+ /* One 16 bit value */
+ if (tran->gray >= (1 << png_ptr->bit_depth))
+ {
+ png_app_warning(png_ptr,
+ "Ignoring attempt to write tRNS chunk out-of-range for bit_depth");
+
+ return;
+ }
+
+ png_save_uint_16(buf, tran->gray);
+ png_write_complete_chunk(png_ptr, png_tRNS, buf, (png_size_t)2);
+ }
+
+ else if (color_type == PNG_COLOR_TYPE_RGB)
+ {
+ /* Three 16 bit values */
+ png_save_uint_16(buf, tran->red);
+ png_save_uint_16(buf + 2, tran->green);
+ png_save_uint_16(buf + 4, tran->blue);
+#ifdef PNG_WRITE_16BIT_SUPPORTED
+ if (png_ptr->bit_depth == 8 && (buf[0] | buf[2] | buf[4]) != 0)
+#else
+ if ((buf[0] | buf[2] | buf[4]) != 0)
+#endif
+ {
+ png_app_warning(png_ptr,
+ "Ignoring attempt to write 16-bit tRNS chunk when bit_depth is 8");
+ return;
+ }
+
+ png_write_complete_chunk(png_ptr, png_tRNS, buf, (png_size_t)6);
+ }
+
+ else
+ {
+ png_app_warning(png_ptr, "Can't write tRNS with an alpha channel");
+ }
+}
+#endif
+
+#ifdef PNG_WRITE_bKGD_SUPPORTED
+/* Write the background chunk */
+void /* PRIVATE */
+png_write_bKGD(png_structrp png_ptr, png_const_color_16p back, int color_type)
+{
+ png_byte buf[6];
+
+ png_debug(1, "in png_write_bKGD");
+
+ if (color_type == PNG_COLOR_TYPE_PALETTE)
+ {
+ if (
+#ifdef PNG_MNG_FEATURES_SUPPORTED
+ (png_ptr->num_palette != 0 ||
+ (png_ptr->mng_features_permitted & PNG_FLAG_MNG_EMPTY_PLTE) == 0) &&
+#endif
+ back->index >= png_ptr->num_palette)
+ {
+ png_warning(png_ptr, "Invalid background palette index");
+ return;
+ }
+
+ buf[0] = back->index;
+ png_write_complete_chunk(png_ptr, png_bKGD, buf, (png_size_t)1);
+ }
+
+ else if ((color_type & PNG_COLOR_MASK_COLOR) != 0)
+ {
+ png_save_uint_16(buf, back->red);
+ png_save_uint_16(buf + 2, back->green);
+ png_save_uint_16(buf + 4, back->blue);
+#ifdef PNG_WRITE_16BIT_SUPPORTED
+ if (png_ptr->bit_depth == 8 && (buf[0] | buf[2] | buf[4]) != 0)
+#else
+ if ((buf[0] | buf[2] | buf[4]) != 0)
+#endif
+ {
+ png_warning(png_ptr,
+ "Ignoring attempt to write 16-bit bKGD chunk when bit_depth is 8");
+
+ return;
+ }
+
+ png_write_complete_chunk(png_ptr, png_bKGD, buf, (png_size_t)6);
+ }
+
+ else
+ {
+ if (back->gray >= (1 << png_ptr->bit_depth))
+ {
+ png_warning(png_ptr,
+ "Ignoring attempt to write bKGD chunk out-of-range for bit_depth");
+
+ return;
+ }
+
+ png_save_uint_16(buf, back->gray);
+ png_write_complete_chunk(png_ptr, png_bKGD, buf, (png_size_t)2);
+ }
+}
+#endif
+
+#ifdef PNG_WRITE_hIST_SUPPORTED
+/* Write the histogram */
+void /* PRIVATE */
+png_write_hIST(png_structrp png_ptr, png_const_uint_16p hist, int num_hist)
+{
+ int i;
+ png_byte buf[3];
+
+ png_debug(1, "in png_write_hIST");
+
+ if (num_hist > (int)png_ptr->num_palette)
+ {
+ png_debug2(3, "num_hist = %d, num_palette = %d", num_hist,
+ png_ptr->num_palette);
+
+ png_warning(png_ptr, "Invalid number of histogram entries specified");
+ return;
+ }
+
+ png_write_chunk_header(png_ptr, png_hIST, (png_uint_32)(num_hist * 2));
+
+ for (i = 0; i < num_hist; i++)
+ {
+ png_save_uint_16(buf, hist[i]);
+ png_write_chunk_data(png_ptr, buf, (png_size_t)2);
+ }
+
+ png_write_chunk_end(png_ptr);
+}
+#endif
+
+#ifdef PNG_WRITE_tEXt_SUPPORTED
+/* Write a tEXt chunk */
+void /* PRIVATE */
+png_write_tEXt(png_structrp png_ptr, png_const_charp key, png_const_charp text,
+ png_size_t text_len)
+{
+ png_uint_32 key_len;
+ png_byte new_key[80];
+
+ png_debug(1, "in png_write_tEXt");
+
+ key_len = png_check_keyword(png_ptr, key, new_key);
+
+ if (key_len == 0)
+ png_error(png_ptr, "tEXt: invalid keyword");
+
+ if (text == NULL || *text == '\0')
+ text_len = 0;
+
+ else
+ text_len = strlen(text);
+
+ if (text_len > PNG_UINT_31_MAX - (key_len+1))
+ png_error(png_ptr, "tEXt: text too long");
+
+ /* Make sure we include the 0 after the key */
+ png_write_chunk_header(png_ptr, png_tEXt,
+ (png_uint_32)/*checked above*/(key_len + text_len + 1));
+ /*
+ * We leave it to the application to meet PNG-1.0 requirements on the
+ * contents of the text. PNG-1.0 through PNG-1.2 discourage the use of
+ * any non-Latin-1 characters except for NEWLINE. ISO PNG will forbid them.
+ * The NUL character is forbidden by PNG-1.0 through PNG-1.2 and ISO PNG.
+ */
+ png_write_chunk_data(png_ptr, new_key, key_len + 1);
+
+ if (text_len != 0)
+ png_write_chunk_data(png_ptr, (png_const_bytep)text, text_len);
+
+ png_write_chunk_end(png_ptr);
+}
+#endif
+
+#ifdef PNG_WRITE_zTXt_SUPPORTED
+/* Write a compressed text chunk */
+void /* PRIVATE */
+png_write_zTXt(png_structrp png_ptr, png_const_charp key, png_const_charp text,
+ int compression)
+{
+ png_uint_32 key_len;
+ png_byte new_key[81];
+ compression_state comp;
+
+ png_debug(1, "in png_write_zTXt");
+
+ if (compression == PNG_TEXT_COMPRESSION_NONE)
+ {
+ png_write_tEXt(png_ptr, key, text, 0);
+ return;
+ }
+
+ if (compression != PNG_TEXT_COMPRESSION_zTXt)
+ png_error(png_ptr, "zTXt: invalid compression type");
+
+ key_len = png_check_keyword(png_ptr, key, new_key);
+
+ if (key_len == 0)
+ png_error(png_ptr, "zTXt: invalid keyword");
+
+ /* Add the compression method and 1 for the keyword separator. */
+ new_key[++key_len] = PNG_COMPRESSION_TYPE_BASE;
+ ++key_len;
+
+ /* Compute the compressed data; do it now for the length */
+ png_text_compress_init(&comp, (png_const_bytep)text,
+ text == NULL ? 0 : strlen(text));
+
+ if (png_text_compress(png_ptr, png_zTXt, &comp, key_len) != Z_OK)
+ png_error(png_ptr, png_ptr->zstream.msg);
+
+ /* Write start of chunk */
+ png_write_chunk_header(png_ptr, png_zTXt, key_len + comp.output_len);
+
+ /* Write key */
+ png_write_chunk_data(png_ptr, new_key, key_len);
+
+ /* Write the compressed data */
+ png_write_compressed_data_out(png_ptr, &comp);
+
+ /* Close the chunk */
+ png_write_chunk_end(png_ptr);
+}
+#endif
+
+#ifdef PNG_WRITE_iTXt_SUPPORTED
+/* Write an iTXt chunk */
+void /* PRIVATE */
+png_write_iTXt(png_structrp png_ptr, int compression, png_const_charp key,
+ png_const_charp lang, png_const_charp lang_key, png_const_charp text)
+{
+ png_uint_32 key_len, prefix_len;
+ png_size_t lang_len, lang_key_len;
+ png_byte new_key[82];
+ compression_state comp;
+
+ png_debug(1, "in png_write_iTXt");
+
+ key_len = png_check_keyword(png_ptr, key, new_key);
+
+ if (key_len == 0)
+ png_error(png_ptr, "iTXt: invalid keyword");
+
+ /* Set the compression flag */
+ switch (compression)
+ {
+ case PNG_ITXT_COMPRESSION_NONE:
+ case PNG_TEXT_COMPRESSION_NONE:
+ compression = new_key[++key_len] = 0; /* no compression */
+ break;
+
+ case PNG_TEXT_COMPRESSION_zTXt:
+ case PNG_ITXT_COMPRESSION_zTXt:
+ compression = new_key[++key_len] = 1; /* compressed */
+ break;
+
+ default:
+ png_error(png_ptr, "iTXt: invalid compression");
+ }
+
+ new_key[++key_len] = PNG_COMPRESSION_TYPE_BASE;
+ ++key_len; /* for the keywod separator */
+
+ /* We leave it to the application to meet PNG-1.0 requirements on the
+ * contents of the text. PNG-1.0 through PNG-1.2 discourage the use of
+ * any non-Latin-1 characters except for NEWLINE. ISO PNG, however,
+ * specifies that the text is UTF-8 and this really doesn't require any
+ * checking.
+ *
+ * The NUL character is forbidden by PNG-1.0 through PNG-1.2 and ISO PNG.
+ *
+ * TODO: validate the language tag correctly (see the spec.)
+ */
+ if (lang == NULL) lang = ""; /* empty language is valid */
+ lang_len = strlen(lang)+1;
+ if (lang_key == NULL) lang_key = ""; /* may be empty */
+ lang_key_len = strlen(lang_key)+1;
+ if (text == NULL) text = ""; /* may be empty */
+
+ prefix_len = key_len;
+ if (lang_len > PNG_UINT_31_MAX-prefix_len)
+ prefix_len = PNG_UINT_31_MAX;
+ else
+ prefix_len = (png_uint_32)(prefix_len + lang_len);
+
+ if (lang_key_len > PNG_UINT_31_MAX-prefix_len)
+ prefix_len = PNG_UINT_31_MAX;
+ else
+ prefix_len = (png_uint_32)(prefix_len + lang_key_len);
+
+ png_text_compress_init(&comp, (png_const_bytep)text, strlen(text));
+
+ if (compression != 0)
+ {
+ if (png_text_compress(png_ptr, png_iTXt, &comp, prefix_len) != Z_OK)
+ png_error(png_ptr, png_ptr->zstream.msg);
+ }
+
+ else
+ {
+ if (comp.input_len > PNG_UINT_31_MAX-prefix_len)
+ png_error(png_ptr, "iTXt: uncompressed text too long");
+
+ /* So the string will fit in a chunk: */
+ comp.output_len = (png_uint_32)/*SAFE*/comp.input_len;
+ }
+
+ png_write_chunk_header(png_ptr, png_iTXt, comp.output_len + prefix_len);
+
+ png_write_chunk_data(png_ptr, new_key, key_len);
+
+ png_write_chunk_data(png_ptr, (png_const_bytep)lang, lang_len);
+
+ png_write_chunk_data(png_ptr, (png_const_bytep)lang_key, lang_key_len);
+
+ if (compression != 0)
+ png_write_compressed_data_out(png_ptr, &comp);
+
+ else
+ png_write_chunk_data(png_ptr, (png_const_bytep)text, comp.output_len);
+
+ png_write_chunk_end(png_ptr);
+}
+#endif
+
+#ifdef PNG_WRITE_oFFs_SUPPORTED
+/* Write the oFFs chunk */
+void /* PRIVATE */
+png_write_oFFs(png_structrp png_ptr, png_int_32 x_offset, png_int_32 y_offset,
+ int unit_type)
+{
+ png_byte buf[9];
+
+ png_debug(1, "in png_write_oFFs");
+
+ if (unit_type >= PNG_OFFSET_LAST)
+ png_warning(png_ptr, "Unrecognized unit type for oFFs chunk");
+
+ png_save_int_32(buf, x_offset);
+ png_save_int_32(buf + 4, y_offset);
+ buf[8] = (png_byte)unit_type;
+
+ png_write_complete_chunk(png_ptr, png_oFFs, buf, (png_size_t)9);
+}
+#endif
+#ifdef PNG_WRITE_pCAL_SUPPORTED
+/* Write the pCAL chunk (described in the PNG extensions document) */
+void /* PRIVATE */
+png_write_pCAL(png_structrp png_ptr, png_charp purpose, png_int_32 X0,
+ png_int_32 X1, int type, int nparams, png_const_charp units,
+ png_charpp params)
+{
+ png_uint_32 purpose_len;
+ png_size_t units_len, total_len;
+ png_size_tp params_len;
+ png_byte buf[10];
+ png_byte new_purpose[80];
+ int i;
+
+ png_debug1(1, "in png_write_pCAL (%d parameters)", nparams);
+
+ if (type >= PNG_EQUATION_LAST)
+ png_error(png_ptr, "Unrecognized equation type for pCAL chunk");
+
+ purpose_len = png_check_keyword(png_ptr, purpose, new_purpose);
+
+ if (purpose_len == 0)
+ png_error(png_ptr, "pCAL: invalid keyword");
+
+ ++purpose_len; /* terminator */
+
+ png_debug1(3, "pCAL purpose length = %d", (int)purpose_len);
+ units_len = strlen(units) + (nparams == 0 ? 0 : 1);
+ png_debug1(3, "pCAL units length = %d", (int)units_len);
+ total_len = purpose_len + units_len + 10;
+
+ params_len = (png_size_tp)png_malloc(png_ptr,
+ (png_alloc_size_t)(nparams * (sizeof (png_size_t))));
+
+ /* Find the length of each parameter, making sure we don't count the
+ * null terminator for the last parameter.
+ */
+ for (i = 0; i < nparams; i++)
+ {
+ params_len[i] = strlen(params[i]) + (i == nparams - 1 ? 0 : 1);
+ png_debug2(3, "pCAL parameter %d length = %lu", i,
+ (unsigned long)params_len[i]);
+ total_len += params_len[i];
+ }
+
+ png_debug1(3, "pCAL total length = %d", (int)total_len);
+ png_write_chunk_header(png_ptr, png_pCAL, (png_uint_32)total_len);
+ png_write_chunk_data(png_ptr, new_purpose, purpose_len);
+ png_save_int_32(buf, X0);
+ png_save_int_32(buf + 4, X1);
+ buf[8] = (png_byte)type;
+ buf[9] = (png_byte)nparams;
+ png_write_chunk_data(png_ptr, buf, (png_size_t)10);
+ png_write_chunk_data(png_ptr, (png_const_bytep)units, (png_size_t)units_len);
+
+ for (i = 0; i < nparams; i++)
+ {
+ png_write_chunk_data(png_ptr, (png_const_bytep)params[i], params_len[i]);
+ }
+
+ png_free(png_ptr, params_len);
+ png_write_chunk_end(png_ptr);
+}
+#endif
+
+#ifdef PNG_WRITE_sCAL_SUPPORTED
+/* Write the sCAL chunk */
+void /* PRIVATE */
+png_write_sCAL_s(png_structrp png_ptr, int unit, png_const_charp width,
+ png_const_charp height)
+{
+ png_byte buf[64];
+ png_size_t wlen, hlen, total_len;
+
+ png_debug(1, "in png_write_sCAL_s");
+
+ wlen = strlen(width);
+ hlen = strlen(height);
+ total_len = wlen + hlen + 2;
+
+ if (total_len > 64)
+ {
+ png_warning(png_ptr, "Can't write sCAL (buffer too small)");
+ return;
+ }
+
+ buf[0] = (png_byte)unit;
+ memcpy(buf + 1, width, wlen + 1); /* Append the '\0' here */
+ memcpy(buf + wlen + 2, height, hlen); /* Do NOT append the '\0' here */
+
+ png_debug1(3, "sCAL total length = %u", (unsigned int)total_len);
+ png_write_complete_chunk(png_ptr, png_sCAL, buf, total_len);
+}
+#endif
+
+#ifdef PNG_WRITE_pHYs_SUPPORTED
+/* Write the pHYs chunk */
+void /* PRIVATE */
+png_write_pHYs(png_structrp png_ptr, png_uint_32 x_pixels_per_unit,
+ png_uint_32 y_pixels_per_unit,
+ int unit_type)
+{
+ png_byte buf[9];
+
+ png_debug(1, "in png_write_pHYs");
+
+ if (unit_type >= PNG_RESOLUTION_LAST)
+ png_warning(png_ptr, "Unrecognized unit type for pHYs chunk");
+
+ png_save_uint_32(buf, x_pixels_per_unit);
+ png_save_uint_32(buf + 4, y_pixels_per_unit);
+ buf[8] = (png_byte)unit_type;
+
+ png_write_complete_chunk(png_ptr, png_pHYs, buf, (png_size_t)9);
+}
+#endif
+
+#ifdef PNG_WRITE_tIME_SUPPORTED
+/* Write the tIME chunk. Use either png_convert_from_struct_tm()
+ * or png_convert_from_time_t(), or fill in the structure yourself.
+ */
+void /* PRIVATE */
+png_write_tIME(png_structrp png_ptr, png_const_timep mod_time)
+{
+ png_byte buf[7];
+
+ png_debug(1, "in png_write_tIME");
+
+ if (mod_time->month > 12 || mod_time->month < 1 ||
+ mod_time->day > 31 || mod_time->day < 1 ||
+ mod_time->hour > 23 || mod_time->second > 60)
+ {
+ png_warning(png_ptr, "Invalid time specified for tIME chunk");
+ return;
+ }
+
+ png_save_uint_16(buf, mod_time->year);
+ buf[2] = mod_time->month;
+ buf[3] = mod_time->day;
+ buf[4] = mod_time->hour;
+ buf[5] = mod_time->minute;
+ buf[6] = mod_time->second;
+
+ png_write_complete_chunk(png_ptr, png_tIME, buf, (png_size_t)7);
+}
+#endif
+
+/* Initializes the row writing capability of libpng */
+void /* PRIVATE */
+png_write_start_row(png_structrp png_ptr)
+{
+#ifdef PNG_WRITE_INTERLACING_SUPPORTED
+ /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
+
+ /* Start of interlace block */
+ static PNG_CONST png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
+
+ /* Offset to next interlace block */
+ static PNG_CONST png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
+
+ /* Start of interlace block in the y direction */
+ static PNG_CONST png_byte png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1};
+
+ /* Offset to next interlace block in the y direction */
+ static PNG_CONST png_byte png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};
+#endif
+
+ png_alloc_size_t buf_size;
+ int usr_pixel_depth;
+
+ png_debug(1, "in png_write_start_row");
+
+ usr_pixel_depth = png_ptr->usr_channels * png_ptr->usr_bit_depth;
+ buf_size = PNG_ROWBYTES(usr_pixel_depth, png_ptr->width) + 1;
+
+ /* 1.5.6: added to allow checking in the row write code. */
+ png_ptr->transformed_pixel_depth = png_ptr->pixel_depth;
+ png_ptr->maximum_pixel_depth = (png_byte)usr_pixel_depth;
+
+ /* Set up row buffer */
+ png_ptr->row_buf = (png_bytep)png_malloc(png_ptr, buf_size);
+
+ png_ptr->row_buf[0] = PNG_FILTER_VALUE_NONE;
+
+#ifdef PNG_WRITE_FILTER_SUPPORTED
+ /* Set up filtering buffer, if using this filter */
+ if (png_ptr->do_filter & PNG_FILTER_SUB)
+ {
+ png_ptr->sub_row = (png_bytep)png_malloc(png_ptr, png_ptr->rowbytes + 1);
+
+ png_ptr->sub_row[0] = PNG_FILTER_VALUE_SUB;
+ }
+
+ /* We only need to keep the previous row if we are using one of these. */
+ if ((png_ptr->do_filter &
+ (PNG_FILTER_AVG | PNG_FILTER_UP | PNG_FILTER_PAETH)) != 0)
+ {
+ /* Set up previous row buffer */
+ png_ptr->prev_row = (png_bytep)png_calloc(png_ptr, buf_size);
+
+ if ((png_ptr->do_filter & PNG_FILTER_UP) != 0)
+ {
+ png_ptr->up_row = (png_bytep)png_malloc(png_ptr,
+ png_ptr->rowbytes + 1);
+
+ png_ptr->up_row[0] = PNG_FILTER_VALUE_UP;
+ }
+
+ if ((png_ptr->do_filter & PNG_FILTER_AVG) != 0)
+ {
+ png_ptr->avg_row = (png_bytep)png_malloc(png_ptr,
+ png_ptr->rowbytes + 1);
+
+ png_ptr->avg_row[0] = PNG_FILTER_VALUE_AVG;
+ }
+
+ if ((png_ptr->do_filter & PNG_FILTER_PAETH) != 0)
+ {
+ png_ptr->paeth_row = (png_bytep)png_malloc(png_ptr,
+ png_ptr->rowbytes + 1);
+
+ png_ptr->paeth_row[0] = PNG_FILTER_VALUE_PAETH;
+ }
+ }
+#endif /* WRITE_FILTER */
+
+#ifdef PNG_WRITE_INTERLACING_SUPPORTED
+ /* If interlaced, we need to set up width and height of pass */
+ if (png_ptr->interlaced != 0)
+ {
+ if ((png_ptr->transformations & PNG_INTERLACE) == 0)
+ {
+ png_ptr->num_rows = (png_ptr->height + png_pass_yinc[0] - 1 -
+ png_pass_ystart[0]) / png_pass_yinc[0];
+
+ png_ptr->usr_width = (png_ptr->width + png_pass_inc[0] - 1 -
+ png_pass_start[0]) / png_pass_inc[0];
+ }
+
+ else
+ {
+ png_ptr->num_rows = png_ptr->height;
+ png_ptr->usr_width = png_ptr->width;
+ }
+ }
+
+ else
+#endif
+ {
+ png_ptr->num_rows = png_ptr->height;
+ png_ptr->usr_width = png_ptr->width;
+ }
+}
+
+/* Internal use only. Called when finished processing a row of data. */
+void /* PRIVATE */
+png_write_finish_row(png_structrp png_ptr)
+{
+#ifdef PNG_WRITE_INTERLACING_SUPPORTED
+ /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
+
+ /* Start of interlace block */
+ static PNG_CONST png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
+
+ /* Offset to next interlace block */
+ static PNG_CONST png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
+
+ /* Start of interlace block in the y direction */
+ static PNG_CONST png_byte png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1};
+
+ /* Offset to next interlace block in the y direction */
+ static PNG_CONST png_byte png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};
+#endif
+
+ png_debug(1, "in png_write_finish_row");
+
+ /* Next row */
+ png_ptr->row_number++;
+
+ /* See if we are done */
+ if (png_ptr->row_number < png_ptr->num_rows)
+ return;
+
+#ifdef PNG_WRITE_INTERLACING_SUPPORTED
+ /* If interlaced, go to next pass */
+ if (png_ptr->interlaced != 0)
+ {
+ png_ptr->row_number = 0;
+ if ((png_ptr->transformations & PNG_INTERLACE) != 0)
+ {
+ png_ptr->pass++;
+ }
+
+ else
+ {
+ /* Loop until we find a non-zero width or height pass */
+ do
+ {
+ png_ptr->pass++;
+
+ if (png_ptr->pass >= 7)
+ break;
+
+ png_ptr->usr_width = (png_ptr->width +
+ png_pass_inc[png_ptr->pass] - 1 -
+ png_pass_start[png_ptr->pass]) /
+ png_pass_inc[png_ptr->pass];
+
+ png_ptr->num_rows = (png_ptr->height +
+ png_pass_yinc[png_ptr->pass] - 1 -
+ png_pass_ystart[png_ptr->pass]) /
+ png_pass_yinc[png_ptr->pass];
+
+ if ((png_ptr->transformations & PNG_INTERLACE) != 0)
+ break;
+
+ } while (png_ptr->usr_width == 0 || png_ptr->num_rows == 0);
+
+ }
+
+ /* Reset the row above the image for the next pass */
+ if (png_ptr->pass < 7)
+ {
+ if (png_ptr->prev_row != NULL)
+ memset(png_ptr->prev_row, 0,
+ (png_size_t)(PNG_ROWBYTES(png_ptr->usr_channels*
+ png_ptr->usr_bit_depth, png_ptr->width)) + 1);
+
+ return;
+ }
+ }
+#endif
+
+ /* If we get here, we've just written the last row, so we need
+ to flush the compressor */
+ png_compress_IDAT(png_ptr, NULL, 0, Z_FINISH);
+}
+
+#ifdef PNG_WRITE_INTERLACING_SUPPORTED
+/* Pick out the correct pixels for the interlace pass.
+ * The basic idea here is to go through the row with a source
+ * pointer and a destination pointer (sp and dp), and copy the
+ * correct pixels for the pass. As the row gets compacted,
+ * sp will always be >= dp, so we should never overwrite anything.
+ * See the default: case for the easiest code to understand.
+ */
+void /* PRIVATE */
+png_do_write_interlace(png_row_infop row_info, png_bytep row, int pass)
+{
+ /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
+
+ /* Start of interlace block */
+ static PNG_CONST png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
+
+ /* Offset to next interlace block */
+ static PNG_CONST png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
+
+ png_debug(1, "in png_do_write_interlace");
+
+ /* We don't have to do anything on the last pass (6) */
+ if (pass < 6)
+ {
+ /* Each pixel depth is handled separately */
+ switch (row_info->pixel_depth)
+ {
+ case 1:
+ {
+ png_bytep sp;
+ png_bytep dp;
+ int shift;
+ int d;
+ int value;
+ png_uint_32 i;
+ png_uint_32 row_width = row_info->width;
+
+ dp = row;
+ d = 0;
+ shift = 7;
+
+ for (i = png_pass_start[pass]; i < row_width;
+ i += png_pass_inc[pass])
+ {
+ sp = row + (png_size_t)(i >> 3);
+ value = (int)(*sp >> (7 - (int)(i & 0x07))) & 0x01;
+ d |= (value << shift);
+
+ if (shift == 0)
+ {
+ shift = 7;
+ *dp++ = (png_byte)d;
+ d = 0;
+ }
+
+ else
+ shift--;
+
+ }
+ if (shift != 7)
+ *dp = (png_byte)d;
+
+ break;
+ }
+
+ case 2:
+ {
+ png_bytep sp;
+ png_bytep dp;
+ int shift;
+ int d;
+ int value;
+ png_uint_32 i;
+ png_uint_32 row_width = row_info->width;
+
+ dp = row;
+ shift = 6;
+ d = 0;
+
+ for (i = png_pass_start[pass]; i < row_width;
+ i += png_pass_inc[pass])
+ {
+ sp = row + (png_size_t)(i >> 2);
+ value = (*sp >> ((3 - (int)(i & 0x03)) << 1)) & 0x03;
+ d |= (value << shift);
+
+ if (shift == 0)
+ {
+ shift = 6;
+ *dp++ = (png_byte)d;
+ d = 0;
+ }
+
+ else
+ shift -= 2;
+ }
+ if (shift != 6)
+ *dp = (png_byte)d;
+
+ break;
+ }
+
+ case 4:
+ {
+ png_bytep sp;
+ png_bytep dp;
+ int shift;
+ int d;
+ int value;
+ png_uint_32 i;
+ png_uint_32 row_width = row_info->width;
+
+ dp = row;
+ shift = 4;
+ d = 0;
+ for (i = png_pass_start[pass]; i < row_width;
+ i += png_pass_inc[pass])
+ {
+ sp = row + (png_size_t)(i >> 1);
+ value = (*sp >> ((1 - (int)(i & 0x01)) << 2)) & 0x0f;
+ d |= (value << shift);
+
+ if (shift == 0)
+ {
+ shift = 4;
+ *dp++ = (png_byte)d;
+ d = 0;
+ }
+
+ else
+ shift -= 4;
+ }
+ if (shift != 4)
+ *dp = (png_byte)d;
+
+ break;
+ }
+
+ default:
+ {
+ png_bytep sp;
+ png_bytep dp;
+ png_uint_32 i;
+ png_uint_32 row_width = row_info->width;
+ png_size_t pixel_bytes;
+
+ /* Start at the beginning */
+ dp = row;
+
+ /* Find out how many bytes each pixel takes up */
+ pixel_bytes = (row_info->pixel_depth >> 3);
+
+ /* Loop through the row, only looking at the pixels that matter */
+ for (i = png_pass_start[pass]; i < row_width;
+ i += png_pass_inc[pass])
+ {
+ /* Find out where the original pixel is */
+ sp = row + (png_size_t)i * pixel_bytes;
+
+ /* Move the pixel */
+ if (dp != sp)
+ memcpy(dp, sp, pixel_bytes);
+
+ /* Next pixel */
+ dp += pixel_bytes;
+ }
+ break;
+ }
+ }
+ /* Set new row width */
+ row_info->width = (row_info->width +
+ png_pass_inc[pass] - 1 -
+ png_pass_start[pass]) /
+ png_pass_inc[pass];
+
+ row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth,
+ row_info->width);
+ }
+}
+#endif
+
+/* This filters the row, chooses which filter to use, if it has not already
+ * been specified by the application, and then writes the row out with the
+ * chosen filter.
+ */
+static void /* PRIVATE */
+png_write_filtered_row(png_structrp png_ptr, png_bytep filtered_row,
+ png_size_t row_bytes);
+
+#define PNG_MAXSUM (((png_uint_32)(-1)) >> 1)
+#define PNG_HISHIFT 10
+#define PNG_LOMASK ((png_uint_32)0xffffL)
+#define PNG_HIMASK ((png_uint_32)(~PNG_LOMASK >> PNG_HISHIFT))
+void /* PRIVATE */
+png_write_find_filter(png_structrp png_ptr, png_row_infop row_info)
+{
+ png_bytep best_row;
+#ifdef PNG_WRITE_FILTER_SUPPORTED
+ png_bytep prev_row, row_buf;
+ png_uint_32 mins, bpp;
+ png_byte filter_to_do = png_ptr->do_filter;
+ png_size_t row_bytes = row_info->rowbytes;
+#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
+ int num_p_filters = png_ptr->num_prev_filters;
+#endif
+
+ png_debug(1, "in png_write_find_filter");
+
+#ifndef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
+ if (png_ptr->row_number == 0 && filter_to_do == PNG_ALL_FILTERS)
+ {
+ /* These will never be selected so we need not test them. */
+ filter_to_do &= ~(PNG_FILTER_UP | PNG_FILTER_PAETH);
+ }
+#endif
+
+ /* Find out how many bytes offset each pixel is */
+ bpp = (row_info->pixel_depth + 7) >> 3;
+
+ prev_row = png_ptr->prev_row;
+#endif
+ best_row = png_ptr->row_buf;
+#ifdef PNG_WRITE_FILTER_SUPPORTED
+ row_buf = best_row;
+ mins = PNG_MAXSUM;
+
+ /* The prediction method we use is to find which method provides the
+ * smallest value when summing the absolute values of the distances
+ * from zero, using anything >= 128 as negative numbers. This is known
+ * as the "minimum sum of absolute differences" heuristic. Other
+ * heuristics are the "weighted minimum sum of absolute differences"
+ * (experimental and can in theory improve compression), and the "zlib
+ * predictive" method (not implemented yet), which does test compressions
+ * of lines using different filter methods, and then chooses the
+ * (series of) filter(s) that give minimum compressed data size (VERY
+ * computationally expensive).
+ *
+ * GRR 980525: consider also
+ *
+ * (1) minimum sum of absolute differences from running average (i.e.,
+ * keep running sum of non-absolute differences & count of bytes)
+ * [track dispersion, too? restart average if dispersion too large?]
+ *
+ * (1b) minimum sum of absolute differences from sliding average, probably
+ * with window size <= deflate window (usually 32K)
+ *
+ * (2) minimum sum of squared differences from zero or running average
+ * (i.e., ~ root-mean-square approach)
+ */
+
+
+ /* We don't need to test the 'no filter' case if this is the only filter
+ * that has been chosen, as it doesn't actually do anything to the data.
+ */
+ if ((filter_to_do & PNG_FILTER_NONE) != 0 && filter_to_do != PNG_FILTER_NONE)
+ {
+ png_bytep rp;
+ png_uint_32 sum = 0;
+ png_size_t i;
+ int v;
+
+ for (i = 0, rp = row_buf + 1; i < row_bytes; i++, rp++)
+ {
+ v = *rp;
+ sum += (v < 128) ? v : 256 - v;
+ }
+
+#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
+ if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
+ {
+ png_uint_32 sumhi, sumlo;
+ int j;
+ sumlo = sum & PNG_LOMASK;
+ sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK; /* Gives us some footroom */
+
+ /* Reduce the sum if we match any of the previous rows */
+ for (j = 0; j < num_p_filters; j++)
+ {
+ if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_NONE)
+ {
+ sumlo = (sumlo * png_ptr->filter_weights[j]) >>
+ PNG_WEIGHT_SHIFT;
+
+ sumhi = (sumhi * png_ptr->filter_weights[j]) >>
+ PNG_WEIGHT_SHIFT;
+ }
+ }
+
+ /* Factor in the cost of this filter (this is here for completeness,
+ * but it makes no sense to have a "cost" for the NONE filter, as
+ * it has the minimum possible computational cost - none).
+ */
+ sumlo = (sumlo * png_ptr->filter_costs[PNG_FILTER_VALUE_NONE]) >>
+ PNG_COST_SHIFT;
+
+ sumhi = (sumhi * png_ptr->filter_costs[PNG_FILTER_VALUE_NONE]) >>
+ PNG_COST_SHIFT;
+
+ if (sumhi > PNG_HIMASK)
+ sum = PNG_MAXSUM;
+
+ else
+ sum = (sumhi << PNG_HISHIFT) + sumlo;
+ }
+#endif
+ mins = sum;
+ }
+
+ /* Sub filter */
+ if (filter_to_do == PNG_FILTER_SUB)
+ /* It's the only filter so no testing is needed */
+ {
+ png_bytep rp, lp, dp;
+ png_size_t i;
+
+ for (i = 0, rp = row_buf + 1, dp = png_ptr->sub_row + 1; i < bpp;
+ i++, rp++, dp++)
+ {
+ *dp = *rp;
+ }
+
+ for (lp = row_buf + 1; i < row_bytes;
+ i++, rp++, lp++, dp++)
+ {
+ *dp = (png_byte)((int)*rp - (int)*lp);
+ }
+
+ best_row = png_ptr->sub_row;
+ }
+
+ else if ((filter_to_do & PNG_FILTER_SUB) != 0)
+ {
+ png_bytep rp, dp, lp;
+ png_uint_32 sum = 0, lmins = mins;
+ png_size_t i;
+ int v;
+
+#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
+ /* We temporarily increase the "minimum sum" by the factor we
+ * would reduce the sum of this filter, so that we can do the
+ * early exit comparison without scaling the sum each time.
+ */
+ if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
+ {
+ int j;
+ png_uint_32 lmhi, lmlo;
+ lmlo = lmins & PNG_LOMASK;
+ lmhi = (lmins >> PNG_HISHIFT) & PNG_HIMASK;
+
+ for (j = 0; j < num_p_filters; j++)
+ {
+ if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_SUB)
+ {
+ lmlo = (lmlo * png_ptr->inv_filter_weights[j]) >>
+ PNG_WEIGHT_SHIFT;
+
+ lmhi = (lmhi * png_ptr->inv_filter_weights[j]) >>
+ PNG_WEIGHT_SHIFT;
+ }
+ }
+
+ lmlo = (lmlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_SUB]) >>
+ PNG_COST_SHIFT;
+
+ lmhi = (lmhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_SUB]) >>
+ PNG_COST_SHIFT;
+
+ if (lmhi > PNG_HIMASK)
+ lmins = PNG_MAXSUM;
+
+ else
+ lmins = (lmhi << PNG_HISHIFT) + lmlo;
+ }
+#endif
+
+ for (i = 0, rp = row_buf + 1, dp = png_ptr->sub_row + 1; i < bpp;
+ i++, rp++, dp++)
+ {
+ v = *dp = *rp;
+
+ sum += (v < 128) ? v : 256 - v;
+ }
+
+ for (lp = row_buf + 1; i < row_bytes;
+ i++, rp++, lp++, dp++)
+ {
+ v = *dp = (png_byte)((int)*rp - (int)*lp);
+
+ sum += (v < 128) ? v : 256 - v;
+
+ if (sum > lmins) /* We are already worse, don't continue. */
+ break;
+ }
+
+#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
+ if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
+ {
+ int j;
+ png_uint_32 sumhi, sumlo;
+ sumlo = sum & PNG_LOMASK;
+ sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK;
+
+ for (j = 0; j < num_p_filters; j++)
+ {
+ if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_SUB)
+ {
+ sumlo = (sumlo * png_ptr->inv_filter_weights[j]) >>
+ PNG_WEIGHT_SHIFT;
+
+ sumhi = (sumhi * png_ptr->inv_filter_weights[j]) >>
+ PNG_WEIGHT_SHIFT;
+ }
+ }
+
+ sumlo = (sumlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_SUB]) >>
+ PNG_COST_SHIFT;
+
+ sumhi = (sumhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_SUB]) >>
+ PNG_COST_SHIFT;
+
+ if (sumhi > PNG_HIMASK)
+ sum = PNG_MAXSUM;
+
+ else
+ sum = (sumhi << PNG_HISHIFT) + sumlo;
+ }
+#endif
+
+ if (sum < mins)
+ {
+ mins = sum;
+ best_row = png_ptr->sub_row;
+ }
+ }
+
+ /* Up filter */
+ if (filter_to_do == PNG_FILTER_UP)
+ {
+ png_bytep rp, dp, pp;
+ png_size_t i;
+
+ for (i = 0, rp = row_buf + 1, dp = png_ptr->up_row + 1,
+ pp = prev_row + 1; i < row_bytes;
+ i++, rp++, pp++, dp++)
+ {
+ *dp = (png_byte)((int)*rp - (int)*pp);
+ }
+
+ best_row = png_ptr->up_row;
+ }
+
+ else if ((filter_to_do & PNG_FILTER_UP) != 0)
+ {
+ png_bytep rp, dp, pp;
+ png_uint_32 sum = 0, lmins = mins;
+ png_size_t i;
+ int v;
+
+
+#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
+ if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
+ {
+ int j;
+ png_uint_32 lmhi, lmlo;
+ lmlo = lmins & PNG_LOMASK;
+ lmhi = (lmins >> PNG_HISHIFT) & PNG_HIMASK;
+
+ for (j = 0; j < num_p_filters; j++)
+ {
+ if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_UP)
+ {
+ lmlo = (lmlo * png_ptr->inv_filter_weights[j]) >>
+ PNG_WEIGHT_SHIFT;
+
+ lmhi = (lmhi * png_ptr->inv_filter_weights[j]) >>
+ PNG_WEIGHT_SHIFT;
+ }
+ }
+
+ lmlo = (lmlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_UP]) >>
+ PNG_COST_SHIFT;
+
+ lmhi = (lmhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_UP]) >>
+ PNG_COST_SHIFT;
+
+ if (lmhi > PNG_HIMASK)
+ lmins = PNG_MAXSUM;
+
+ else
+ lmins = (lmhi << PNG_HISHIFT) + lmlo;
+ }
+#endif
+
+ for (i = 0, rp = row_buf + 1, dp = png_ptr->up_row + 1,
+ pp = prev_row + 1; i < row_bytes; i++)
+ {
+ v = *dp++ = (png_byte)((int)*rp++ - (int)*pp++);
+
+ sum += (v < 128) ? v : 256 - v;
+
+ if (sum > lmins) /* We are already worse, don't continue. */
+ break;
+ }
+
+#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
+ if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
+ {
+ int j;
+ png_uint_32 sumhi, sumlo;
+ sumlo = sum & PNG_LOMASK;
+ sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK;
+
+ for (j = 0; j < num_p_filters; j++)
+ {
+ if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_UP)
+ {
+ sumlo = (sumlo * png_ptr->filter_weights[j]) >>
+ PNG_WEIGHT_SHIFT;
+
+ sumhi = (sumhi * png_ptr->filter_weights[j]) >>
+ PNG_WEIGHT_SHIFT;
+ }
+ }
+
+ sumlo = (sumlo * png_ptr->filter_costs[PNG_FILTER_VALUE_UP]) >>
+ PNG_COST_SHIFT;
+
+ sumhi = (sumhi * png_ptr->filter_costs[PNG_FILTER_VALUE_UP]) >>
+ PNG_COST_SHIFT;
+
+ if (sumhi > PNG_HIMASK)
+ sum = PNG_MAXSUM;
+
+ else
+ sum = (sumhi << PNG_HISHIFT) + sumlo;
+ }
+#endif
+
+ if (sum < mins)
+ {
+ mins = sum;
+ best_row = png_ptr->up_row;
+ }
+ }
+
+ /* Avg filter */
+ if (filter_to_do == PNG_FILTER_AVG)
+ {
+ png_bytep rp, dp, pp, lp;
+ png_uint_32 i;
+
+ for (i = 0, rp = row_buf + 1, dp = png_ptr->avg_row + 1,
+ pp = prev_row + 1; i < bpp; i++)
+ {
+ *dp++ = (png_byte)((int)*rp++ - ((int)*pp++ / 2));
+ }
+
+ for (lp = row_buf + 1; i < row_bytes; i++)
+ {
+ *dp++ =
+ (png_byte)((int)*rp++ - (((int)*pp++ + (int)*lp++) / 2));
+ }
+ best_row = png_ptr->avg_row;
+ }
+
+ else if ((filter_to_do & PNG_FILTER_AVG) != 0)
+ {
+ png_bytep rp, dp, pp, lp;
+ png_uint_32 sum = 0, lmins = mins;
+ png_size_t i;
+ int v;
+
+#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
+ if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
+ {
+ int j;
+ png_uint_32 lmhi, lmlo;
+ lmlo = lmins & PNG_LOMASK;
+ lmhi = (lmins >> PNG_HISHIFT) & PNG_HIMASK;
+
+ for (j = 0; j < num_p_filters; j++)
+ {
+ if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_AVG)
+ {
+ lmlo = (lmlo * png_ptr->inv_filter_weights[j]) >>
+ PNG_WEIGHT_SHIFT;
+
+ lmhi = (lmhi * png_ptr->inv_filter_weights[j]) >>
+ PNG_WEIGHT_SHIFT;
+ }
+ }
+
+ lmlo = (lmlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_AVG]) >>
+ PNG_COST_SHIFT;
+
+ lmhi = (lmhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_AVG]) >>
+ PNG_COST_SHIFT;
+
+ if (lmhi > PNG_HIMASK)
+ lmins = PNG_MAXSUM;
+
+ else
+ lmins = (lmhi << PNG_HISHIFT) + lmlo;
+ }
+#endif
+
+ for (i = 0, rp = row_buf + 1, dp = png_ptr->avg_row + 1,
+ pp = prev_row + 1; i < bpp; i++)
+ {
+ v = *dp++ = (png_byte)((int)*rp++ - ((int)*pp++ / 2));
+
+ sum += (v < 128) ? v : 256 - v;
+ }
+
+ for (lp = row_buf + 1; i < row_bytes; i++)
+ {
+ v = *dp++ =
+ (png_byte)(((int)*rp++ - ((int)*pp++ + (int)*lp++) / 2));
+
+ sum += (v < 128) ? v : 256 - v;
+
+ if (sum > lmins) /* We are already worse, don't continue. */
+ break;
+ }
+
+#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
+ if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
+ {
+ int j;
+ png_uint_32 sumhi, sumlo;
+ sumlo = sum & PNG_LOMASK;
+ sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK;
+
+ for (j = 0; j < num_p_filters; j++)
+ {
+ if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_NONE)
+ {
+ sumlo = (sumlo * png_ptr->filter_weights[j]) >>
+ PNG_WEIGHT_SHIFT;
+
+ sumhi = (sumhi * png_ptr->filter_weights[j]) >>
+ PNG_WEIGHT_SHIFT;
+ }
+ }
+
+ sumlo = (sumlo * png_ptr->filter_costs[PNG_FILTER_VALUE_AVG]) >>
+ PNG_COST_SHIFT;
+
+ sumhi = (sumhi * png_ptr->filter_costs[PNG_FILTER_VALUE_AVG]) >>
+ PNG_COST_SHIFT;
+
+ if (sumhi > PNG_HIMASK)
+ sum = PNG_MAXSUM;
+
+ else
+ sum = (sumhi << PNG_HISHIFT) + sumlo;
+ }
+#endif
+
+ if (sum < mins)
+ {
+ mins = sum;
+ best_row = png_ptr->avg_row;
+ }
+ }
+
+ /* Paeth filter */
+ if ((filter_to_do == PNG_FILTER_PAETH) != 0)
+ {
+ png_bytep rp, dp, pp, cp, lp;
+ png_size_t i;
+
+ for (i = 0, rp = row_buf + 1, dp = png_ptr->paeth_row + 1,
+ pp = prev_row + 1; i < bpp; i++)
+ {
+ *dp++ = (png_byte)((int)*rp++ - (int)*pp++);
+ }
+
+ for (lp = row_buf + 1, cp = prev_row + 1; i < row_bytes; i++)
+ {
+ int a, b, c, pa, pb, pc, p;
+
+ b = *pp++;
+ c = *cp++;
+ a = *lp++;
+
+ p = b - c;
+ pc = a - c;
+
+#ifdef PNG_USE_ABS
+ pa = abs(p);
+ pb = abs(pc);
+ pc = abs(p + pc);
+#else
+ pa = p < 0 ? -p : p;
+ pb = pc < 0 ? -pc : pc;
+ pc = (p + pc) < 0 ? -(p + pc) : p + pc;
+#endif
+
+ p = (pa <= pb && pa <=pc) ? a : (pb <= pc) ? b : c;
+
+ *dp++ = (png_byte)((int)*rp++ - p);
+ }
+ best_row = png_ptr->paeth_row;
+ }
+
+ else if ((filter_to_do & PNG_FILTER_PAETH) != 0)
+ {
+ png_bytep rp, dp, pp, cp, lp;
+ png_uint_32 sum = 0, lmins = mins;
+ png_size_t i;
+ int v;
+
+#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
+ if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
+ {
+ int j;
+ png_uint_32 lmhi, lmlo;
+ lmlo = lmins & PNG_LOMASK;
+ lmhi = (lmins >> PNG_HISHIFT) & PNG_HIMASK;
+
+ for (j = 0; j < num_p_filters; j++)
+ {
+ if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_PAETH)
+ {
+ lmlo = (lmlo * png_ptr->inv_filter_weights[j]) >>
+ PNG_WEIGHT_SHIFT;
+
+ lmhi = (lmhi * png_ptr->inv_filter_weights[j]) >>
+ PNG_WEIGHT_SHIFT;
+ }
+ }
+
+ lmlo = (lmlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_PAETH]) >>
+ PNG_COST_SHIFT;
+
+ lmhi = (lmhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_PAETH]) >>
+ PNG_COST_SHIFT;
+
+ if (lmhi > PNG_HIMASK)
+ lmins = PNG_MAXSUM;
+
+ else
+ lmins = (lmhi << PNG_HISHIFT) + lmlo;
+ }
+#endif
+
+ for (i = 0, rp = row_buf + 1, dp = png_ptr->paeth_row + 1,
+ pp = prev_row + 1; i < bpp; i++)
+ {
+ v = *dp++ = (png_byte)((int)*rp++ - (int)*pp++);
+
+ sum += (v < 128) ? v : 256 - v;
+ }
+
+ for (lp = row_buf + 1, cp = prev_row + 1; i < row_bytes; i++)
+ {
+ int a, b, c, pa, pb, pc, p;
+
+ b = *pp++;
+ c = *cp++;
+ a = *lp++;
+
+#ifndef PNG_SLOW_PAETH
+ p = b - c;
+ pc = a - c;
+#ifdef PNG_USE_ABS
+ pa = abs(p);
+ pb = abs(pc);
+ pc = abs(p + pc);
+#else
+ pa = p < 0 ? -p : p;
+ pb = pc < 0 ? -pc : pc;
+ pc = (p + pc) < 0 ? -(p + pc) : p + pc;
+#endif
+ p = (pa <= pb && pa <=pc) ? a : (pb <= pc) ? b : c;
+#else /* SLOW_PAETH */
+ p = a + b - c;
+ pa = abs(p - a);
+ pb = abs(p - b);
+ pc = abs(p - c);
+
+ if (pa <= pb && pa <= pc)
+ p = a;
+
+ else if (pb <= pc)
+ p = b;
+
+ else
+ p = c;
+#endif /* SLOW_PAETH */
+
+ v = *dp++ = (png_byte)((int)*rp++ - p);
+
+ sum += (v < 128) ? v : 256 - v;
+
+ if (sum > lmins) /* We are already worse, don't continue. */
+ break;
+ }
+
+#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
+ if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
+ {
+ int j;
+ png_uint_32 sumhi, sumlo;
+ sumlo = sum & PNG_LOMASK;
+ sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK;
+
+ for (j = 0; j < num_p_filters; j++)
+ {
+ if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_PAETH)
+ {
+ sumlo = (sumlo * png_ptr->filter_weights[j]) >>
+ PNG_WEIGHT_SHIFT;
+
+ sumhi = (sumhi * png_ptr->filter_weights[j]) >>
+ PNG_WEIGHT_SHIFT;
+ }
+ }
+
+ sumlo = (sumlo * png_ptr->filter_costs[PNG_FILTER_VALUE_PAETH]) >>
+ PNG_COST_SHIFT;
+
+ sumhi = (sumhi * png_ptr->filter_costs[PNG_FILTER_VALUE_PAETH]) >>
+ PNG_COST_SHIFT;
+
+ if (sumhi > PNG_HIMASK)
+ sum = PNG_MAXSUM;
+
+ else
+ sum = (sumhi << PNG_HISHIFT) + sumlo;
+ }
+#endif
+
+ if (sum < mins)
+ {
+ best_row = png_ptr->paeth_row;
+ }
+ }
+#endif /* WRITE_FILTER */
+
+ /* Do the actual writing of the filtered row data from the chosen filter. */
+ png_write_filtered_row(png_ptr, best_row, row_info->rowbytes+1);
+
+#ifdef PNG_WRITE_FILTER_SUPPORTED
+#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
+ /* Save the type of filter we picked this time for future calculations */
+ if (png_ptr->num_prev_filters > 0)
+ {
+ int j;
+
+ for (j = 1; j < num_p_filters; j++)
+ {
+ png_ptr->prev_filters[j] = png_ptr->prev_filters[j - 1];
+ }
+
+ png_ptr->prev_filters[j] = best_row[0];
+ }
+#endif
+#endif /* WRITE_FILTER */
+}
+
+
+/* Do the actual writing of a previously filtered row. */
+static void
+png_write_filtered_row(png_structrp png_ptr, png_bytep filtered_row,
+ png_size_t full_row_length/*includes filter byte*/)
+{
+ png_debug(1, "in png_write_filtered_row");
+
+ png_debug1(2, "filter = %d", filtered_row[0]);
+
+ png_compress_IDAT(png_ptr, filtered_row, full_row_length, Z_NO_FLUSH);
+
+#ifdef PNG_WRITE_FILTER_SUPPORTED
+ /* Swap the current and previous rows */
+ if (png_ptr->prev_row != NULL)
+ {
+ png_bytep tptr;
+
+ tptr = png_ptr->prev_row;
+ png_ptr->prev_row = png_ptr->row_buf;
+ png_ptr->row_buf = tptr;
+ }
+#endif /* WRITE_FILTER */
+
+ /* Finish row - updates counters and flushes zlib if last row */
+ png_write_finish_row(png_ptr);
+
+#ifdef PNG_WRITE_FLUSH_SUPPORTED
+ png_ptr->flush_rows++;
+
+ if (png_ptr->flush_dist > 0 &&
+ png_ptr->flush_rows >= png_ptr->flush_dist)
+ {
+ png_write_flush(png_ptr);
+ }
+#endif /* WRITE_FLUSH */
+}
+#endif /* WRITE */
--- /dev/null
+diff --git a/src/3rdparty/libpng/pngconf.h b/src/3rdparty/libpng/pngconf.h
+index 3f9493e..535c2df 100644
+--- a/src/3rdparty/libpng/pngconf.h
++++ b/src/3rdparty/libpng/pngconf.h
+@@ -196,7 +196,7 @@
+ # define PNGCAPI __watcall
+ # endif
+
+-# if defined(__GNUC__) || (defined(_MSC_VER) && (_MSC_VER >= 800))
++# if defined(__GNUC__) || (defined (_MSC_VER) && (_MSC_VER >= 800)) || defined(__WINSCW__)
+ # define PNGCAPI __cdecl
+ # if PNG_API_RULE == 1
+ /* If this line results in an error __stdcall is not understood and
+diff --git a/src/3rdparty/libpng/pnglibconf.h b/src/3rdparty/libpng/pnglibconf.h
+index b4ec3c3..f0fdcf8 100644
+--- a/src/3rdparty/libpng/pnglibconf.h
++++ b/src/3rdparty/libpng/pnglibconf.h
+@@ -27,7 +27,9 @@
+ #define PNG_CHECK_FOR_INVALID_INDEX_SUPPORTED
+ #define PNG_COLORSPACE_SUPPORTED
+ #define PNG_CONSOLE_IO_SUPPORTED
++#ifndef _WIN32_WCE
+ #define PNG_CONVERT_tIME_SUPPORTED
++#endif
+ #define PNG_EASY_ACCESS_SUPPORTED
+ /*#undef PNG_ERROR_NUMBERS_SUPPORTED*/
+ #define PNG_ERROR_TEXT_SUPPORTED
+@@ -106,12 +108,14 @@
+ #define PNG_SET_OPTION_SUPPORTED
+ #define PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
+ #define PNG_SET_USER_LIMITS_SUPPORTED
++#ifndef _WIN32_WCE
+ #define PNG_SIMPLIFIED_READ_AFIRST_SUPPORTED
+ #define PNG_SIMPLIFIED_READ_BGR_SUPPORTED
+ #define PNG_SIMPLIFIED_READ_SUPPORTED
+ #define PNG_SIMPLIFIED_WRITE_AFIRST_SUPPORTED
+ #define PNG_SIMPLIFIED_WRITE_BGR_SUPPORTED
+ #define PNG_SIMPLIFIED_WRITE_SUPPORTED
++#endif
+ #define PNG_STDIO_SUPPORTED
+ #define PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED
+ #define PNG_TEXT_SUPPORTED
+diff --git a/src/3rdparty/libpng/pngpriv.h b/src/3rdparty/libpng/pngpriv.h
+index 5980a3f..4031d73 100644
+--- a/src/3rdparty/libpng/pngpriv.h
++++ b/src/3rdparty/libpng/pngpriv.h
+@@ -23,6 +23,12 @@
+ #ifndef PNGPRIV_H
+ #define PNGPRIV_H
+
++#ifdef _MSC_VER
++# ifndef _CRT_SECURE_NO_DEPRECATE
++# define _CRT_SECURE_NO_DEPRECATE
++# endif
++#endif
++
+ /* Feature Test Macros. The following are defined here to ensure that correctly
+ * implemented libraries reveal the APIs libpng needs to build and hide those
+ * that are not needed and potentially damaging to the compilation.
+@@ -215,6 +221,11 @@
+ # endif
+ #endif /* Setting PNG_BUILD_DLL if required */
+
++/* Modfied for usage in Qt: Do not export the libpng APIs */
++#ifdef PNG_BUILD_DLL
++#undef PNG_BUILD_DLL
++#endif
++
+ /* See pngconf.h for more details: the builder of the library may set this on
+ * the command line to the right thing for the specific compilation system or it
+ * may be automagically set above (at present we know of no system where it does
+@@ -425,7 +436,9 @@
+
+ #if defined(WIN32) || defined(_Windows) || defined(_WINDOWS) || \
+ defined(_WIN32) || defined(__WIN32__)
+-# include <windows.h> /* defines _WINDOWS_ macro */
++# if !defined(__SYMBIAN32__)
++# include <windows.h> /* defines _WINDOWS_ macro */
++# endif
+ #endif
+ #endif /* PNG_VERSION_INFO_ONLY */
+
+@@ -436,7 +449,7 @@
+
+ /* Memory model/platform independent fns */
+ #ifndef PNG_ABORT
+-# ifdef _WINDOWS_
++# if defined(_WINDOWS_) || defined(_WIN32_WCE)
+ # define PNG_ABORT() ExitProcess(0)
+ # else
+ # define PNG_ABORT() abort()
${CMAKE_CURRENT_SOURCE_DIR}/image/qimage_ssse3.cpp
)
-if(WITH_PNG AND PNG_FOUND)
+if(WITH_PNG)
set(GUI_HEADERS
${GUI_HEADERS}
${CMAKE_CURRENT_SOURCE_DIR}/image/qpnghandler_p.h
${GUI_SOURCES}
${CMAKE_CURRENT_SOURCE_DIR}/image/qpnghandler.cpp
)
- set(EXTRA_GUI_LIBS
- ${EXTRA_GUI_LIBS}
- ${PNG_LIBRARIES}
- )
- include_directories(${PNG_INCLUDE_DIRS})
- add_definitions(${PNG_DEFINITIONS})
+ if(PNG_FOUND)
+ set(EXTRA_GUI_LIBS
+ ${EXTRA_GUI_LIBS}
+ ${PNG_LIBRARIES}
+ )
+ include_directories(${PNG_INCLUDE_DIRS})
+ add_definitions(${PNG_DEFINITIONS})
+ else()
+ set(GUI_SOURCES
+ ${GUI_SOURCES}
+ ${CMAKE_SOURCE_DIR}/src/3rdparty/libpng/png.c
+ ${CMAKE_SOURCE_DIR}/src/3rdparty/libpng/pngerror.c
+ ${CMAKE_SOURCE_DIR}/src/3rdparty/libpng/pngget.c
+ ${CMAKE_SOURCE_DIR}/src/3rdparty/libpng/pngmem.c
+ ${CMAKE_SOURCE_DIR}/src/3rdparty/libpng/pngpread.c
+ ${CMAKE_SOURCE_DIR}/src/3rdparty/libpng/pngread.c
+ ${CMAKE_SOURCE_DIR}/src/3rdparty/libpng/pngrio.c
+ ${CMAKE_SOURCE_DIR}/src/3rdparty/libpng/pngrtran.c
+ ${CMAKE_SOURCE_DIR}/src/3rdparty/libpng/pngrutil.c
+ ${CMAKE_SOURCE_DIR}/src/3rdparty/libpng/pngset.c
+ ${CMAKE_SOURCE_DIR}/src/3rdparty/libpng/pngtrans.c
+ ${CMAKE_SOURCE_DIR}/src/3rdparty/libpng/pngwio.c
+ ${CMAKE_SOURCE_DIR}/src/3rdparty/libpng/pngwrite.c
+ ${CMAKE_SOURCE_DIR}/src/3rdparty/libpng/pngwtran.c
+ ${CMAKE_SOURCE_DIR}/src/3rdparty/libpng/pngwutil.c
+ )
+ add_definitions(-DPNG_ARM_NEON_OPT=0)
+ endif()
endif()
if(WITH_JPEG AND JPEG_FOUND)
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