1 INSTALLATION INSTRUCTIONS for the Independent JPEG Group's JPEG software
3 Copyright (C) 1991-1998, Thomas G. Lane.
4 This file is part of the Independent JPEG Group's software.
5 For conditions of distribution and use, see the accompanying README file.
8 This file explains how to configure and install the IJG software. We have
9 tried to make this software extremely portable and flexible, so that it can be
10 adapted to almost any environment. The downside of this decision is that the
11 installation process is complicated. We have provided shortcuts to simplify
12 the task on common systems. But in any case, you will need at least a little
13 familiarity with C programming and program build procedures for your system.
15 If you are only using this software as part of a larger program, the larger
16 program's installation procedure may take care of configuring the IJG code.
17 For example, Ghostscript's installation script will configure the IJG code.
18 You don't need to read this file if you just want to compile Ghostscript.
20 If you are on a Unix machine, you may not need to read this file at all.
25 If that doesn't complain, do
27 (better do "make -n install" first to see if the makefile will put the files
28 where you want them). Read further if you run into snags or want to customize
29 the code for your system.
36 Configuring the software:
37 using the automatic "configure" script
38 using one of the supplied jconfig and makefile files
42 Installing the software
45 Hints for specific systems
51 Before installing the software you must unpack the distributed source code.
52 Since you are reading this file, you have probably already succeeded in this
53 task. However, there is a potential for error if you needed to convert the
54 files to the local standard text file format (for example, if you are on
55 MS-DOS you may have converted LF end-of-line to CR/LF). You must apply
56 such conversion to all the files EXCEPT those whose names begin with "test".
57 The test files contain binary data; if you change them in any way then the
58 self-test will give bad results.
60 Please check the last section of this file to see if there are hints for the
61 specific machine or compiler you are using.
64 CONFIGURING THE SOFTWARE
65 ========================
67 To configure the IJG code for your system, you need to create two files:
68 * jconfig.h: contains values for system-dependent #define symbols.
69 * Makefile: controls the compilation process.
70 (On a non-Unix machine, you may create "project files" or some other
71 substitute for a Makefile. jconfig.h is needed in any environment.)
73 We provide three different ways to generate these files:
74 * On a Unix system, you can just run the "configure" script.
75 * We provide sample jconfig files and makefiles for popular machines;
76 if your machine matches one of the samples, just copy the right sample
77 files to jconfig.h and Makefile.
78 * If all else fails, read the instructions below and make your own files.
81 Configuring the software using the automatic "configure" script
82 ---------------------------------------------------------------
84 If you are on a Unix machine, you can just type
86 and let the configure script construct appropriate configuration files.
87 If you're using "csh" on an old version of System V, you might need to type
89 instead to prevent csh from trying to execute configure itself.
90 Expect configure to run for a few minutes, particularly on slower machines;
91 it works by compiling a series of test programs.
93 Configure was created with GNU Autoconf and it follows the usual conventions
94 for GNU configure scripts. It makes a few assumptions that you may want to
95 override. You can do this by providing optional switches to configure:
97 * If you want to build libjpeg as a shared library, say
98 ./configure --enable-shared
99 To get both shared and static libraries, say
100 ./configure --enable-shared --enable-static
101 Note that these switches invoke GNU libtool to take care of system-dependent
102 shared library building methods. If things don't work this way, please try
103 running configure without either switch; that should build a static library
104 without using libtool. If that works, your problem is probably with libtool
105 not with the IJG code. libtool is fairly new and doesn't support all flavors
106 of Unix yet. (You might be able to find a newer version of libtool than the
107 one included with libjpeg; see ftp.gnu.org. Report libtool problems to
108 bug-libtool@gnu.org.)
110 * Configure will use gcc (GNU C compiler) if it's available, otherwise cc.
111 To force a particular compiler to be selected, use the CC option, for example
113 The same method can be used to include any unusual compiler switches.
114 For example, on HP-UX you probably want to say
115 ./configure CC='cc -Aa'
116 to get HP's compiler to run in ANSI mode.
118 * The default CFLAGS setting is "-O" for non-gcc compilers, "-O2" for gcc.
119 You can override this by saying, for example,
120 ./configure CFLAGS='-g'
121 if you want to compile with debugging support.
123 * Configure will set up the makefile so that "make install" will install files
124 into /usr/local/bin, /usr/local/man, etc. You can specify an installation
125 prefix other than "/usr/local" by giving configure the option "--prefix=PATH".
127 * If you don't have a lot of swap space, you may need to enable the IJG
128 software's internal virtual memory mechanism. To do this, give the option
129 "--enable-maxmem=N" where N is the default maxmemory limit in megabytes.
130 This is discussed in more detail under "Selecting a memory manager", below.
131 You probably don't need to worry about this on reasonably-sized Unix machines,
132 unless you plan to process very large images.
134 Configure has some other features that are useful if you are cross-compiling
135 or working in a network of multiple machine types; but if you need those
136 features, you probably already know how to use them.
139 Configuring the software using one of the supplied jconfig and makefile files
140 -----------------------------------------------------------------------------
142 If you have one of these systems, you can just use the provided configuration
145 Makefile jconfig file System and/or compiler
147 makefile.manx jconfig.manx Amiga, Manx Aztec C
148 makefile.sas jconfig.sas Amiga, SAS C
149 makeproj.mac jconfig.mac Apple Macintosh, Metrowerks CodeWarrior
150 mak*jpeg.st jconfig.st Atari ST/STE/TT, Pure C or Turbo C
151 makefile.bcc jconfig.bcc MS-DOS or OS/2, Borland C
152 makefile.dj jconfig.dj MS-DOS, DJGPP (Delorie's port of GNU C)
153 makefile.mc6 jconfig.mc6 MS-DOS, Microsoft C (16-bit only)
154 makefile.wat jconfig.wat MS-DOS, OS/2, or Windows NT, Watcom C
155 makefile.vc jconfig.vc Windows NT/95, MS Visual C++
156 make*.ds jconfig.vc Windows NT/95, MS Developer Studio
157 makefile.mms jconfig.vms Digital VMS, with MMS software
158 makefile.vms jconfig.vms Digital VMS, without MMS software
160 Copy the proper jconfig file to jconfig.h and the makefile to Makefile (or
161 whatever your system uses as the standard makefile name). For more info see
162 the appropriate system-specific hints section near the end of this file.
165 Configuring the software by hand
166 --------------------------------
168 First, generate a jconfig.h file. If you are moderately familiar with C,
169 the comments in jconfig.doc should be enough information to do this; just
170 copy jconfig.doc to jconfig.h and edit it appropriately. Otherwise, you may
171 prefer to use the ckconfig.c program. You will need to compile and execute
172 ckconfig.c by hand --- we hope you know at least enough to do that.
173 ckconfig.c may not compile the first try (in fact, the whole idea is for it
174 to fail if anything is going to). If you get compile errors, fix them by
175 editing ckconfig.c according to the directions given in ckconfig.c. Once
176 you get it to run, it will write a suitable jconfig.h file, and will also
177 print out some advice about which makefile to use.
179 You may also want to look at the canned jconfig files, if there is one for a
180 system similar to yours.
182 Second, select a makefile and copy it to Makefile (or whatever your system
183 uses as the standard makefile name). The most generic makefiles we provide
185 makefile.ansi: if your C compiler supports function prototypes
186 makefile.unix: if not.
187 (You have function prototypes if ckconfig.c put "#define HAVE_PROTOTYPES"
188 in jconfig.h.) You may want to start from one of the other makefiles if
189 there is one for a system similar to yours.
191 Look over the selected Makefile and adjust options as needed. In particular
192 you may want to change the CC and CFLAGS definitions. For instance, if you
193 are using GCC, set CC=gcc. If you had to use any compiler switches to get
194 ckconfig.c to work, make sure the same switches are in CFLAGS.
196 If you are on a system that doesn't use makefiles, you'll need to set up
197 project files (or whatever you do use) to compile all the source files and
198 link them into executable files cjpeg, djpeg, jpegtran, rdjpgcom, and wrjpgcom.
199 See the file lists in any of the makefiles to find out which files go into
200 each program. Note that the provided makefiles all make a "library" file
201 libjpeg first, but you don't have to do that if you don't want to; the file
202 lists identify which source files are actually needed for compression,
203 decompression, or both. As a last resort, you can make a batch script that
204 just compiles everything and links it all together; makefile.vms is an example
205 of this (it's for VMS systems that have no make-like utility).
207 Here are comments about some specific configuration decisions you'll
213 These programs can use a Unix-like command line style which supports
214 redirection and piping, like this:
215 cjpeg inputfile >outputfile
216 cjpeg <inputfile >outputfile
217 source program | cjpeg >outputfile
218 The simpler "two file" command line style is just
219 cjpeg inputfile outputfile
220 You may prefer the two-file style, particularly if you don't have pipes.
222 You MUST use two-file style on any system that doesn't cope well with binary
223 data fed through stdin/stdout; this is true for some MS-DOS compilers, for
224 example. If you're not on a Unix system, it's safest to assume you need
225 two-file style. (But if your compiler provides either the Posix-standard
226 fdopen() library routine or a Microsoft-compatible setmode() routine, you
227 can safely use the Unix command line style, by defining USE_FDOPEN or
228 USE_SETMODE respectively.)
230 To use the two-file style, make jconfig.h say "#define TWO_FILE_COMMANDLINE".
232 Selecting a memory manager
233 --------------------------
235 The IJG code is capable of working on images that are too big to fit in main
236 memory; data is swapped out to temporary files as necessary. However, the
237 code to do this is rather system-dependent. We provide five different
240 * jmemansi.c This version uses the ANSI-standard library routine tmpfile(),
241 which not all non-ANSI systems have. On some systems
242 tmpfile() may put the temporary file in a non-optimal
243 location; if you don't like what it does, use jmemname.c.
245 * jmemname.c This version creates named temporary files. For anything
246 except a Unix machine, you'll need to configure the
247 select_file_name() routine appropriately; see the comments
248 near the head of jmemname.c. If you use this version, define
249 NEED_SIGNAL_CATCHER in jconfig.h to make sure the temp files
250 are removed if the program is aborted.
252 * jmemnobs.c (That stands for No Backing Store :-).) This will compile on
253 almost any system, but it assumes you have enough main memory
254 or virtual memory to hold the biggest images you work with.
256 * jmemdos.c This should be used with most 16-bit MS-DOS compilers.
257 See the system-specific notes about MS-DOS for more info.
258 IMPORTANT: if you use this, define USE_MSDOS_MEMMGR in
259 jconfig.h, and include the assembly file jmemdosa.asm in the
260 programs. The supplied makefiles and jconfig files for
261 16-bit MS-DOS compilers already do both.
263 * jmemmac.c Custom version for Apple Macintosh; see the system-specific
264 notes for Macintosh for more info.
266 To use a particular memory manager, change the SYSDEPMEM variable in your
267 makefile to equal the corresponding object file name (for example, jmemansi.o
268 or jmemansi.obj for jmemansi.c).
270 If you have plenty of (real or virtual) main memory, just use jmemnobs.c.
271 "Plenty" means about ten bytes for every pixel in the largest images
272 you plan to process, so a lot of systems don't meet this criterion.
273 If yours doesn't, try jmemansi.c first. If that doesn't compile, you'll have
274 to use jmemname.c; be sure to adjust select_file_name() for local conditions.
275 You may also need to change unlink() to remove() in close_backing_store().
277 Except with jmemnobs.c or jmemmac.c, you need to adjust the DEFAULT_MAX_MEM
278 setting to a reasonable value for your system (either by adding a #define for
279 DEFAULT_MAX_MEM to jconfig.h, or by adding a -D switch to the Makefile).
280 This value limits the amount of data space the program will attempt to
281 allocate. Code and static data space isn't counted, so the actual memory
282 needs for cjpeg or djpeg are typically 100 to 150Kb more than the max-memory
283 setting. Larger max-memory settings reduce the amount of I/O needed to
284 process a large image, but too large a value can result in "insufficient
285 memory" failures. On most Unix machines (and other systems with virtual
286 memory), just set DEFAULT_MAX_MEM to several million and forget it. At the
287 other end of the spectrum, for MS-DOS machines you probably can't go much
288 above 300K to 400K. (On MS-DOS the value refers to conventional memory only.
289 Extended/expanded memory is handled separately by jmemdos.c.)
292 BUILDING THE SOFTWARE
293 =====================
295 Now you should be able to compile the software. Just say "make" (or
296 whatever's necessary to start the compilation). Have a cup of coffee.
298 Here are some things that could go wrong:
300 If your compiler complains about undefined structures, you should be able to
301 shut it up by putting "#define INCOMPLETE_TYPES_BROKEN" in jconfig.h.
303 If you have trouble with missing system include files or inclusion of the
304 wrong ones, read jinclude.h. This shouldn't happen if you used configure
305 or ckconfig.c to set up jconfig.h.
307 There are a fair number of routines that do not use all of their parameters;
308 some compilers will issue warnings about this, which you can ignore. There
309 are also a few configuration checks that may give "unreachable code" warnings.
310 Any other warning deserves investigation.
312 If you don't have a getenv() library routine, define NO_GETENV.
314 Also see the system-specific hints, below.
320 As a quick test of functionality we've included a small sample image in
322 testorig.jpg Starting point for the djpeg tests.
323 testimg.ppm The output of djpeg testorig.jpg
324 testimg.bmp The output of djpeg -bmp -colors 256 testorig.jpg
325 testimg.jpg The output of cjpeg testimg.ppm
326 testprog.jpg Progressive-mode equivalent of testorig.jpg.
327 testimgp.jpg The output of cjpeg -progressive -optimize testimg.ppm
328 (The first- and second-generation .jpg files aren't identical since JPEG is
329 lossy.) If you can generate duplicates of the testimg* files then you
330 probably have working programs.
332 With most of the makefiles, "make test" will perform the necessary
335 If you're using a makefile that doesn't provide the test option, run djpeg
336 and cjpeg by hand and compare the output files to testimg* with whatever
337 binary file comparison tool you have. The files should be bit-for-bit
340 If the programs complain "MAX_ALLOC_CHUNK is wrong, please fix", then you
341 need to reduce MAX_ALLOC_CHUNK to a value that fits in type size_t.
342 Try adding "#define MAX_ALLOC_CHUNK 65520L" to jconfig.h. A less likely
343 configuration error is "ALIGN_TYPE is wrong, please fix": defining ALIGN_TYPE
344 as long should take care of that one.
346 If the cjpeg test run fails with "Missing Huffman code table entry", it's a
347 good bet that you needed to define RIGHT_SHIFT_IS_UNSIGNED. Go back to the
348 configuration step and run ckconfig.c. (This is a good plan for any other
351 If you are using Unix (one-file) command line style on a non-Unix system,
352 it's a good idea to check that binary I/O through stdin/stdout actually
353 works. You should get the same results from "djpeg <testorig.jpg >out.ppm"
354 as from "djpeg -outfile out.ppm testorig.jpg". Note that the makefiles all
355 use the latter style and therefore do not exercise stdin/stdout! If this
356 check fails, try recompiling with USE_SETMODE or USE_FDOPEN defined.
357 If it still doesn't work, better use two-file style.
359 If you chose a memory manager other than jmemnobs.c, you should test that
360 temporary-file usage works. Try "djpeg -bmp -colors 256 -max 0 testorig.jpg"
361 and make sure its output matches testimg.bmp. If you have any really large
362 images handy, try compressing them with -optimize and/or decompressing with
363 -colors 256 to make sure your DEFAULT_MAX_MEM setting is not too large.
365 NOTE: this is far from an exhaustive test of the JPEG software; some modules,
366 such as 1-pass color quantization, are not exercised at all. It's just a
367 quick test to give you some confidence that you haven't missed something
371 INSTALLING THE SOFTWARE
372 =======================
374 Once you're done with the above steps, you can install the software by
375 copying the executable files (cjpeg, djpeg, jpegtran, rdjpgcom, and wrjpgcom)
376 to wherever you normally install programs. On Unix systems, you'll also want
377 to put the man pages (cjpeg.1, djpeg.1, jpegtran.1, rdjpgcom.1, wrjpgcom.1)
378 in the man-page directory. The pre-fab makefiles don't support this step
379 since there's such a wide variety of installation procedures on different
382 If you generated a Makefile with the "configure" script, you can just say
384 to install the programs and their man pages into the standard places.
385 (You'll probably need to be root to do this.) We recommend first saying
387 to see where configure thought the files should go. You may need to edit
388 the Makefile, particularly if your system's conventions for man page
389 filenames don't match what configure expects.
391 If you want to install the IJG library itself, for use in compiling other
392 programs besides ours, then you need to put the four include files
393 jpeglib.h jerror.h jconfig.h jmorecfg.h
394 into your include-file directory, and put the library file libjpeg.a
395 (extension may vary depending on system) wherever library files go.
396 If you generated a Makefile with "configure", it will do what it thinks
397 is the right thing if you say
406 If you like, you can #define PROGRESS_REPORT (in jconfig.h) to enable display
407 of percent-done progress reports. The routine provided in cdjpeg.c merely
408 prints percentages to stderr, but you can customize it to do something
411 Utah RLE file format support:
413 We distribute the software with support for RLE image files (Utah Raster
414 Toolkit format) disabled, because the RLE support won't compile without the
415 Utah library. If you have URT version 3.1 or later, you can enable RLE
417 1. #define RLE_SUPPORTED in jconfig.h.
418 2. Add a -I option to CFLAGS in the Makefile for the directory
419 containing the URT .h files (typically the "include"
420 subdirectory of the URT distribution).
421 3. Add -L... -lrle to LDLIBS in the Makefile, where ... specifies
422 the directory containing the URT "librle.a" file (typically the
423 "lib" subdirectory of the URT distribution).
425 Support for 12-bit-deep pixel data:
427 The JPEG standard allows either 8-bit or 12-bit data precision. (For color,
428 this means 8 or 12 bits per channel, of course.) If you need to work with
429 deeper than 8-bit data, you can compile the IJG code for 12-bit operation.
431 1. In jmorecfg.h, define BITS_IN_JSAMPLE as 12 rather than 8.
432 2. In jconfig.h, undefine BMP_SUPPORTED, RLE_SUPPORTED, and TARGA_SUPPORTED,
433 because the code for those formats doesn't handle 12-bit data and won't
434 even compile. (The PPM code does work, as explained below. The GIF
435 code works too; it scales 8-bit GIF data to and from 12-bit depth
437 3. Compile. Don't expect "make test" to pass, since the supplied test
438 files are for 8-bit data.
440 Currently, 12-bit support does not work on 16-bit-int machines.
442 Note that a 12-bit version will not read 8-bit JPEG files, nor vice versa;
443 so you'll want to keep around a regular 8-bit compilation as well.
444 (Run-time selection of data depth, to allow a single copy that does both,
445 is possible but would probably slow things down considerably; it's very low
448 The PPM reader (rdppm.c) can read 12-bit data from either text-format or
449 binary-format PPM and PGM files. Binary-format PPM/PGM files which have a
450 maxval greater than 255 are assumed to use 2 bytes per sample, LSB first
451 (little-endian order). As of early 1995, 2-byte binary format is not
452 officially supported by the PBMPLUS library, but it is expected that a
453 future release of PBMPLUS will support it. Note that the PPM reader will
454 read files of any maxval regardless of the BITS_IN_JSAMPLE setting; incoming
455 data is automatically rescaled to either maxval=255 or maxval=4095 as
456 appropriate for the cjpeg bit depth.
458 The PPM writer (wrppm.c) will normally write 2-byte binary PPM or PGM
459 format, maxval 4095, when compiled with BITS_IN_JSAMPLE=12. Since this
460 format is not yet widely supported, you can disable it by compiling wrppm.c
461 with PPM_NORAWWORD defined; then the data is scaled down to 8 bits to make a
462 standard 1-byte/sample PPM or PGM file. (Yes, this means still another copy
463 of djpeg to keep around. But hopefully you won't need it for very long.
464 Poskanzer's supposed to get that new PBMPLUS release out Real Soon Now.)
466 Of course, if you are working with 12-bit data, you probably have it stored
467 in some other, nonstandard format. In that case you'll probably want to
468 write your own I/O modules to read and write your format.
470 Note that a 12-bit version of cjpeg always runs in "-optimize" mode, in
471 order to generate valid Huffman tables. This is necessary because our
472 default Huffman tables only cover 8-bit data.
476 If you need to make a smaller version of the JPEG software, some optional
477 functions can be removed at compile time. See the xxx_SUPPORTED #defines in
478 jconfig.h and jmorecfg.h. If at all possible, we recommend that you leave in
479 decoder support for all valid JPEG files, to ensure that you can read anyone's
480 output. Taking out support for image file formats that you don't use is the
481 most painless way to make the programs smaller. Another possibility is to
482 remove some of the DCT methods: in particular, the "IFAST" method may not be
483 enough faster than the others to be worth keeping on your machine. (If you
484 do remove ISLOW or IFAST, be sure to redefine JDCT_DEFAULT or JDCT_FASTEST
485 to a supported method, by adding a #define in jconfig.h.)
491 Unless you own a Cray, you'll probably be interested in making the JPEG
492 software go as fast as possible. This section covers some machine-dependent
493 optimizations you may want to try. We suggest that before trying any of
494 this, you first get the basic installation to pass the self-test step.
495 Repeat the self-test after any optimization to make sure that you haven't
498 The integer DCT routines perform a lot of multiplications. These
499 multiplications must yield 32-bit results, but none of their input values
500 are more than 16 bits wide. On many machines, notably the 680x0 and 80x86
501 CPUs, a 16x16=>32 bit multiply instruction is faster than a full 32x32=>32
502 bit multiply. Unfortunately there is no portable way to specify such a
503 multiplication in C, but some compilers can generate one when you use the
504 right combination of casts. See the MULTIPLYxxx macro definitions in
505 jdct.h. If your compiler makes "int" be 32 bits and "short" be 16 bits,
506 defining SHORTxSHORT_32 is fairly likely to work. When experimenting with
507 alternate definitions, be sure to test not only whether the code still works
508 (use the self-test), but also whether it is actually faster --- on some
509 compilers, alternate definitions may compute the right answer, yet be slower
510 than the default. Timing cjpeg on a large PGM (grayscale) input file is the
511 best way to check this, as the DCT will be the largest fraction of the runtime
512 in that mode. (Note: some of the distributed compiler-specific jconfig files
513 already contain #define switches to select appropriate MULTIPLYxxx
516 If your machine has sufficiently fast floating point hardware, you may find
517 that the float DCT method is faster than the integer DCT methods, even
518 after tweaking the integer multiply macros. In that case you may want to
519 make the float DCT be the default method. (The only objection to this is
520 that float DCT results may vary slightly across machines.) To do that, add
521 "#define JDCT_DEFAULT JDCT_FLOAT" to jconfig.h. Even if you don't change
522 the default, you should redefine JDCT_FASTEST, which is the method selected
523 by djpeg's -fast switch. Don't forget to update the documentation files
524 (usage.doc and/or cjpeg.1, djpeg.1) to agree with what you've done.
526 If access to "short" arrays is slow on your machine, it may be a win to
527 define type JCOEF as int rather than short. This will cost a good deal of
528 memory though, particularly in some multi-pass modes, so don't do it unless
529 you have memory to burn and short is REALLY slow.
531 If your compiler can compile function calls in-line, make sure the INLINE
532 macro in jmorecfg.h is defined as the keyword that marks a function
533 inline-able. Some compilers have a switch that tells the compiler to inline
534 any function it thinks is profitable (e.g., -finline-functions for gcc).
535 Enabling such a switch is likely to make the compiled code bigger but faster.
537 In general, it's worth trying the maximum optimization level of your compiler,
538 and experimenting with any optional optimizations such as loop unrolling.
539 (Unfortunately, far too many compilers have optimizer bugs ... be prepared to
540 back off if the code fails self-test.) If you do any experimentation along
541 these lines, please report the optimal settings to jpeg-info@uunet.uu.net so
542 we can mention them in future releases. Be sure to specify your machine and
546 HINTS FOR SPECIFIC SYSTEMS
547 ==========================
549 We welcome reports on changes needed for systems not mentioned here. Submit
550 'em to jpeg-info@uunet.uu.net. Also, if configure or ckconfig.c is wrong
551 about how to configure the JPEG software for your system, please let us know.
556 (Thanks to Simon Middleton for these hints on compiling with Desktop C.)
557 After renaming the files according to Acorn conventions, take a copy of
558 makefile.ansi, change all occurrences of 'libjpeg.a' to 'libjpeg.o' and
559 change these definitions as indicated:
561 CFLAGS= -throwback -IC: -Wn
567 Also add a new line '.c.o:; $(cc) $< $(cflags) -c -o $@'. Remove the
568 lines '$(RM) libjpeg.o' and '$(AR2) libjpeg.o' and the 'jconfig.h'
571 Copy jconfig.doc to jconfig.h. Edit jconfig.h to define TWO_FILE_COMMANDLINE
572 and CHAR_IS_UNSIGNED.
574 Run the makefile using !AMU not !Make. If you want to use the 'clean' and
575 'test' makefile entries then you will have to fiddle with the syntax a bit
576 and rename the test files.
581 SAS C 6.50 reportedly is too buggy to compile the IJG code properly.
582 A patch to update to 6.51 is available from SAS or AmiNet FTP sites.
584 The supplied config files are set up to use jmemname.c as the memory
585 manager, with temporary files being created on the device named by
591 Copy the project files makcjpeg.st, makdjpeg.st, maktjpeg.st, and makljpeg.st
592 to cjpeg.prj, djpeg.prj, jpegtran.prj, and libjpeg.prj respectively. The
593 project files should work as-is with Pure C. For Turbo C, change library
594 filenames "pc..." to "tc..." in each project file. Note that libjpeg.prj
595 selects jmemansi.c as the recommended memory manager. You'll probably want to
596 adjust the DEFAULT_MAX_MEM setting --- you want it to be a couple hundred K
597 less than your normal free memory. Put "#define DEFAULT_MAX_MEM nnnn" into
598 jconfig.h to do this.
600 To use the 68881/68882 coprocessor for the floating point DCT, add the
601 compiler option "-8" to the project files and replace pcfltlib.lib with
602 pc881lib.lib in cjpeg.prj and djpeg.prj. Or if you don't have a
603 coprocessor, you may prefer to remove the float DCT code by undefining
604 DCT_FLOAT_SUPPORTED in jmorecfg.h (since without a coprocessor, the float
605 code will be too slow to be useful). In that case, you can delete
606 pcfltlib.lib from the project files.
608 Note that you must make libjpeg.lib before making cjpeg.ttp, djpeg.ttp,
609 or jpegtran.ttp. You'll have to perform the self-test by hand.
611 We haven't bothered to include project files for rdjpgcom and wrjpgcom.
612 Those source files should just be compiled by themselves; they don't
613 depend on the JPEG library.
615 There is a bug in some older versions of the Turbo C library which causes the
616 space used by temporary files created with "tmpfile()" not to be freed after
617 an abnormal program exit. If you check your disk afterwards, you will find
618 cluster chains that are allocated but not used by a file. This should not
619 happen in cjpeg/djpeg/jpegtran, since we enable a signal catcher to explicitly
620 close temp files before exiting. But if you use the JPEG library with your
621 own code, be sure to supply a signal catcher, or else use a different
622 system-dependent memory manager.
627 Should you be so fortunate as to be running JPEG on a Cray YMP, there is a
628 compiler bug in old versions of Cray's Standard C (prior to 3.1). If you
629 still have an old compiler, you'll need to insert a line reading
630 "#pragma novector" just before the loop
631 for (i = 1; i <= (int) htbl->bits[l]; i++)
632 huffsize[p++] = (char) l;
633 in fix_huff_tbl (in V5beta1, line 204 of jchuff.c and line 176 of jdhuff.c).
634 [This bug may or may not still occur with the current IJG code, but it's
635 probably a dead issue anyway...]
640 If you have HP-UX 7.05 or later with the "software development" C compiler,
641 you should run the compiler in ANSI mode. If using the configure script,
643 ./configure CC='cc -Aa'
644 (or -Ae if you prefer). If configuring by hand, use makefile.ansi and add
645 "-Aa" to the CFLAGS line in the makefile.
647 If you have a pre-7.05 system, or if you are using the non-ANSI C compiler
648 delivered with a minimum HP-UX system, then you must use makefile.unix
649 (and do NOT add -Aa); or just run configure without the CC option.
651 On HP 9000 series 800 machines, the HP C compiler is buggy in revisions prior
652 to A.08.07. If you get complaints about "not a typedef name", you'll have to
653 use makefile.unix, or run configure without the CC option.
656 Macintosh, generic comments:
658 The supplied user-interface files (cjpeg.c, djpeg.c, etc) are set up to
659 provide a Unix-style command line interface. You can use this interface on
660 the Mac by means of the ccommand() library routine provided by Metrowerks
661 CodeWarrior or Think C. This is only appropriate for testing the library,
662 however; to make a user-friendly equivalent of cjpeg/djpeg you'd really want
663 to develop a Mac-style user interface. There isn't a complete example
664 available at the moment, but there are some helpful starting points:
665 1. Sam Bushell's free "To JPEG" applet provides drag-and-drop conversion to
666 JPEG under System 7 and later. This only illustrates how to use the
667 compression half of the library, but it does a very nice job of that part.
668 The CodeWarrior source code is available from http://www.pobox.com/~jsam.
669 2. Jim Brunner prepared a Mac-style user interface for both compression and
670 decompression. Unfortunately, it hasn't been updated since IJG v4, and
671 the library's API has changed considerably since then. Still it may be of
672 some help, particularly as a guide to compiling the IJG code under Think C.
673 Jim's code is available from the Info-Mac archives, at sumex-aim.stanford.edu
674 or mirrors thereof; see file /info-mac/dev/src/jpeg-convert-c.hqx.
676 jmemmac.c is the recommended memory manager back end for Macintosh. It uses
677 NewPtr/DisposePtr instead of malloc/free, and has a Mac-specific
678 implementation of jpeg_mem_available(). It also creates temporary files that
679 follow Mac conventions. (That part of the code relies on System-7-or-later OS
680 functions. See the comments in jmemmac.c if you need to run it on System 6.)
681 NOTE that USE_MAC_MEMMGR must be defined in jconfig.h to use jmemmac.c.
683 You can also use jmemnobs.c, if you don't care about handling images larger
684 than available memory. If you use any memory manager back end other than
685 jmemmac.c, we recommend replacing "malloc" and "free" by "NewPtr" and
686 "DisposePtr", because Mac C libraries often have peculiar implementations of
687 malloc/free. (For instance, free() may not return the freed space to the
688 Mac Memory Manager. This is undesirable for the IJG code because jmemmgr.c
689 already clumps space requests.)
692 Macintosh, Metrowerks CodeWarrior:
694 The Unix-command-line-style interface can be used by defining USE_CCOMMAND.
695 You'll also need to define TWO_FILE_COMMANDLINE to avoid stdin/stdout.
696 This means that when using the cjpeg/djpeg programs, you'll have to type the
697 input and output file names in the "Arguments" text-edit box, rather than
698 using the file radio buttons. (Perhaps USE_FDOPEN or USE_SETMODE would
699 eliminate the problem, but I haven't heard from anyone who's tried it.)
701 On 680x0 Macs, Metrowerks defines type "double" as a 10-byte IEEE extended
702 float. jmemmgr.c won't like this: it wants sizeof(ALIGN_TYPE) to be a power
703 of 2. Add "#define ALIGN_TYPE long" to jconfig.h to eliminate the complaint.
705 The supplied configuration file jconfig.mac can be used for your jconfig.h;
706 it includes all the recommended symbol definitions. If you have AppleScript
707 installed, you can run the supplied script makeproj.mac to create CodeWarrior
708 project files for the library and the testbed applications, then build the
709 library and applications. (Thanks to Dan Sears and Don Agro for this nifty
710 hack, which saves us from trying to maintain CodeWarrior project files as part
711 of the IJG distribution...)
716 The documentation in Jim Brunner's "JPEG Convert" source code (see above)
717 includes detailed build instructions for Think C; it's probably somewhat
718 out of date for the current release, but may be helpful.
720 If you want to build the minimal command line version, proceed as follows.
721 You'll have to prepare project files for the programs; we don't include any
722 in the distribution since they are not text files. Use the file lists in
723 any of the supplied makefiles as a guide. Also add the ANSI and Unix C
724 libraries in a separate segment. You may need to divide the JPEG files into
725 more than one segment; we recommend dividing compression and decompression
726 modules. Define USE_CCOMMAND in jconfig.h so that the ccommand() routine is
727 called. You must also define TWO_FILE_COMMANDLINE because stdin/stdout
728 don't handle binary data correctly.
730 On 680x0 Macs, Think C defines type "double" as a 12-byte IEEE extended float.
731 jmemmgr.c won't like this: it wants sizeof(ALIGN_TYPE) to be a power of 2.
732 Add "#define ALIGN_TYPE long" to jconfig.h to eliminate the complaint.
734 jconfig.mac should work as a jconfig.h configuration file for Think C,
735 but the makeproj.mac AppleScript script is specific to CodeWarrior. Sorry.
740 MIPS's cc version 1.31 has a rather nasty optimization bug. Don't use -O
741 if you have that compiler version. (Use "cc -V" to check the version.)
742 Note that the R3000 chip is found in workstations from DEC and others.
745 MS-DOS, generic comments for 16-bit compilers:
747 The IJG code is designed to work well in 80x86 "small" or "medium" memory
748 models (i.e., data pointers are 16 bits unless explicitly declared "far";
749 code pointers can be either size). You may be able to use small model to
750 compile cjpeg or djpeg by itself, but you will probably have to use medium
751 model for any larger application. This won't make much difference in
752 performance. You *will* take a noticeable performance hit if you use a
753 large-data memory model, and you should avoid "huge" model if at all
754 possible. Be sure that NEED_FAR_POINTERS is defined in jconfig.h if you use
755 a small-data memory model; be sure it is NOT defined if you use a large-data
756 model. (The supplied makefiles and jconfig files for Borland and Microsoft C
757 compile in medium model and define NEED_FAR_POINTERS.)
759 The DOS-specific memory manager, jmemdos.c, should be used if possible.
760 It needs some assembly-code routines which are in jmemdosa.asm; make sure
761 your makefile assembles that file and includes it in the library. If you
762 don't have a suitable assembler, you can get pre-assembled object files for
763 jmemdosa by FTP from ftp.uu.net:/graphics/jpeg/jdosaobj.zip. (DOS-oriented
764 distributions of the IJG source code often include these object files.)
766 When using jmemdos.c, jconfig.h must define USE_MSDOS_MEMMGR and must set
767 MAX_ALLOC_CHUNK to less than 64K (65520L is a typical value). If your
768 C library's far-heap malloc() can't allocate blocks that large, reduce
769 MAX_ALLOC_CHUNK to whatever it can handle.
771 If you can't use jmemdos.c for some reason --- for example, because you
772 don't have an assembler to assemble jmemdosa.asm --- you'll have to fall
773 back to jmemansi.c or jmemname.c. You'll probably still need to set
774 MAX_ALLOC_CHUNK in jconfig.h, because most DOS C libraries won't malloc()
775 more than 64K at a time. IMPORTANT: if you use jmemansi.c or jmemname.c,
776 you will have to compile in a large-data memory model in order to get the
777 right stdio library. Too bad.
779 wrjpgcom needs to be compiled in large model, because it malloc()s a 64KB
780 work area to hold the comment text. If your C library's malloc can't
781 handle that, reduce MAX_COM_LENGTH as necessary in wrjpgcom.c.
783 Most MS-DOS compilers treat stdin/stdout as text files, so you must use
784 two-file command line style. But if your compiler has either fdopen() or
785 setmode(), you can use one-file style if you like. To do this, define
786 USE_SETMODE or USE_FDOPEN so that stdin/stdout will be set to binary mode.
787 (USE_SETMODE seems to work with more DOS compilers than USE_FDOPEN.) You
788 should test that I/O through stdin/stdout produces the same results as I/O
789 to explicitly named files... the "make test" procedures in the supplied
790 makefiles do NOT use stdin/stdout.
793 MS-DOS, generic comments for 32-bit compilers:
795 None of the above comments about memory models apply if you are using a
796 32-bit flat-memory-space environment, such as DJGPP or Watcom C. (And you
797 should use one if you have it, as performance will be much better than
798 8086-compatible code!) For flat-memory-space compilers, do NOT define
799 NEED_FAR_POINTERS, and do NOT use jmemdos.c. Use jmemnobs.c if the
800 environment supplies adequate virtual memory, otherwise use jmemansi.c or
803 You'll still need to be careful about binary I/O through stdin/stdout.
804 See the last paragraph of the previous section.
809 Be sure to convert all the source files to DOS text format (CR/LF newlines).
810 Although Borland C will often work OK with unmodified Unix (LF newlines)
811 source files, sometimes it will give bogus compile errors.
812 "Illegal character '#'" is the most common such error. (This is true with
813 Borland C 3.1, but perhaps is fixed in newer releases.)
815 If you want one-file command line style, just undefine TWO_FILE_COMMANDLINE.
816 jconfig.bcc already includes #define USE_SETMODE to make this work.
817 (fdopen does not work correctly.)
822 makefile.mc6 works with Microsoft C, DOS Visual C++, etc. It should only
823 be used if you want to build a 16-bit (small or medium memory model) program.
825 If you want one-file command line style, just undefine TWO_FILE_COMMANDLINE.
826 jconfig.mc6 already includes #define USE_SETMODE to make this work.
827 (fdopen does not work correctly.)
829 Note that this makefile assumes that the working copy of itself is called
830 "makefile". If you want to call it something else, say "makefile.mak",
831 be sure to adjust the dependency line that reads "$(RFILE) : makefile".
832 Otherwise the make will fail because it doesn't know how to create "makefile".
833 Worse, some releases of Microsoft's make utilities give an incorrect error
834 message in this situation.
836 Old versions of MS C fail with an "out of macro expansion space" error
837 because they can't cope with the macro TRACEMS8 (defined in jerror.h).
838 If this happens to you, the easiest solution is to change TRACEMS8 to
839 expand to nothing. You'll lose the ability to dump out JPEG coefficient
840 tables with djpeg -debug -debug, but at least you can compile.
842 Original MS C 6.0 is very buggy; it compiles incorrect code unless you turn
843 off optimization entirely (remove -O from CFLAGS). 6.00A is better, but it
844 still generates bad code if you enable loop optimizations (-Ol or -Ox).
846 MS C 8.0 crashes when compiling jquant1.c with optimization switch /Oo ...
847 which is on by default. To work around this bug, compile that one file
851 Microsoft Windows (all versions), generic comments:
853 Some Windows system include files define typedef boolean as "unsigned char".
854 The IJG code also defines typedef boolean, but we make it "int" by default.
855 This doesn't affect the IJG programs because we don't import those Windows
856 include files. But if you use the JPEG library in your own program, and some
857 of your program's files import one definition of boolean while some import the
858 other, you can get all sorts of mysterious problems. A good preventive step
859 is to make the IJG library use "unsigned char" for boolean. To do that,
860 add something like this to your jconfig.h file:
861 /* Define "boolean" as unsigned char, not int, per Windows custom */
862 #ifndef __RPCNDR_H__ /* don't conflict if rpcndr.h already read */
863 typedef unsigned char boolean;
865 #define HAVE_BOOLEAN /* prevent jmorecfg.h from redefining it */
866 (This is already in jconfig.vc, by the way.)
868 windef.h contains the declarations
871 Since jmorecfg.h tries to define FAR as empty, you may get a compiler
872 warning if you include both jpeglib.h and windef.h (which windows.h
873 includes). To suppress the warning, you can put "#ifndef FAR"/"#endif"
874 around the line "#define FAR" in jmorecfg.h.
876 When using the library in a Windows application, you will almost certainly
877 want to modify or replace the error handler module jerror.c, since our
878 default error handler does a couple of inappropriate things:
879 1. it tries to write error and warning messages on stderr;
880 2. in event of a fatal error, it exits by calling exit().
882 A simple stopgap solution for problem 1 is to replace the line
883 fprintf(stderr, "%s\n", buffer);
884 (in output_message in jerror.c) with
885 MessageBox(GetActiveWindow(),buffer,"JPEG Error",MB_OK|MB_ICONERROR);
886 It's highly recommended that you at least do that much, since otherwise
887 error messages will disappear into nowhere. (Beginning with IJG v6b, this
888 code is already present in jerror.c; just define USE_WINDOWS_MESSAGEBOX in
889 jconfig.h to enable it.)
891 The proper solution for problem 2 is to return control to your calling
892 application after a library error. This can be done with the setjmp/longjmp
893 technique discussed in libjpeg.doc and illustrated in example.c. (NOTE:
894 some older Windows C compilers provide versions of setjmp/longjmp that
895 don't actually work under Windows. You may need to use the Windows system
896 functions Catch and Throw instead.)
898 The recommended memory manager under Windows is jmemnobs.c; in other words,
899 let Windows do any virtual memory management needed. You should NOT use
900 jmemdos.c nor jmemdosa.asm under Windows.
902 For Windows 3.1, we recommend compiling in medium or large memory model;
903 for newer Windows versions, use a 32-bit flat memory model. (See the MS-DOS
904 sections above for more info about memory models.) In the 16-bit memory
905 models only, you'll need to put
906 #define MAX_ALLOC_CHUNK 65520L /* Maximum request to malloc() */
907 into jconfig.h to limit allocation chunks to 64Kb. (Without that, you'd
908 have to use huge memory model, which slows things down unnecessarily.)
909 jmemnobs.c works without modification in large or flat memory models, but to
910 use medium model, you need to modify its jpeg_get_large and jpeg_free_large
911 routines to allocate far memory. In any case, you might like to replace
912 its calls to malloc and free with direct calls on Windows memory allocation
915 You may also want to modify jdatasrc.c and jdatadst.c to use Windows file
916 operations rather than fread/fwrite. This is only necessary if your C
917 compiler doesn't provide a competent implementation of C stdio functions.
919 You might want to tweak the RGB_xxx macros in jmorecfg.h so that the library
920 will accept or deliver color pixels in BGR sample order, not RGB; BGR order
921 is usually more convenient under Windows. Note that this change will break
922 the sample applications cjpeg/djpeg, but the library itself works fine.
925 Many people want to convert the IJG library into a DLL. This is reasonably
926 straightforward, but watch out for the following:
928 1. Don't try to compile as a DLL in small or medium memory model; use
929 large model, or even better, 32-bit flat model. Many places in the IJG code
930 assume the address of a local variable is an ordinary (not FAR) pointer;
931 that isn't true in a medium-model DLL.
933 2. Microsoft C cannot pass file pointers between applications and DLLs.
934 (See Microsoft Knowledge Base, PSS ID Number Q50336.) So jdatasrc.c and
935 jdatadst.c don't work if you open a file in your application and then pass
936 the pointer to the DLL. One workaround is to make jdatasrc.c/jdatadst.c
937 part of your main application rather than part of the DLL.
939 3. You'll probably need to modify the macros GLOBAL() and EXTERN() to
940 attach suitable linkage keywords to the exported routine names. Similarly,
941 you'll want to modify METHODDEF() and JMETHOD() to ensure function pointers
942 are declared in a way that lets application routines be called back through
943 the function pointers. These macros are in jmorecfg.h. Typical definitions
944 for a 16-bit DLL are:
945 #define GLOBAL(type) type _far _pascal _loadds _export
946 #define EXTERN(type) extern type _far _pascal _loadds
947 #define METHODDEF(type) static type _far _pascal
948 #define JMETHOD(type,methodname,arglist) \
949 type (_far _pascal *methodname) arglist
950 For a 32-bit DLL you may want something like
951 #define GLOBAL(type) __declspec(dllexport) type
952 #define EXTERN(type) extern __declspec(dllexport) type
953 Although not all the GLOBAL routines are actually intended to be called by
954 the application, the performance cost of making them all DLL entry points is
957 The unmodified IJG library presents a very C-specific application interface,
958 so the resulting DLL is only usable from C or C++ applications. There has
959 been some talk of writing wrapper code that would present a simpler interface
960 usable from other languages, such as Visual Basic. This is on our to-do list
961 but hasn't been very high priority --- any volunteers out there?
964 Microsoft Windows, Borland C:
966 The provided jconfig.bcc should work OK in a 32-bit Windows environment,
967 but you'll need to tweak it in a 16-bit environment (you'd need to define
968 NEED_FAR_POINTERS and MAX_ALLOC_CHUNK). Beware that makefile.bcc will need
969 alteration if you want to use it for Windows --- in particular, you should
970 use jmemnobs.c not jmemdos.c under Windows.
972 Borland C++ 4.5 fails with an internal compiler error when trying to compile
973 jdmerge.c in 32-bit mode. If enough people complain, perhaps Borland will fix
974 it. In the meantime, the simplest known workaround is to add a redundant
975 definition of the variable range_limit in h2v1_merged_upsample(), at the head
976 of the block that handles odd image width (about line 268 in v6 jdmerge.c):
977 /* If image width is odd, do the last output column separately */
978 if (cinfo->output_width & 1) {
979 register JSAMPLE * range_limit = cinfo->sample_range_limit; /* ADD THIS */
980 cb = GETJSAMPLE(*inptr1);
981 Pretty bizarre, especially since the very similar routine h2v2_merged_upsample
982 doesn't trigger the bug.
983 Recent reports suggest that this bug does not occur with "bcc32a" (the
984 Pentium-optimized version of the compiler).
986 Another report from a user of Borland C 4.5 was that incorrect code (leading
987 to a color shift in processed images) was produced if any of the following
988 optimization switch combinations were used:
992 So try backing off on optimization if you see such a problem. (Are there
993 several different releases all numbered "4.5"??)
996 Microsoft Windows, Microsoft Visual C++:
998 jconfig.vc should work OK with any Microsoft compiler for a 32-bit memory
999 model. makefile.vc is intended for command-line use. (If you are using
1000 the Developer Studio environment, you may prefer the DevStudio project
1003 Some users feel that it's easier to call the library from C++ code if you
1004 force VC++ to treat the library as C++ code, which you can do by renaming
1005 all the *.c files to *.cpp (and adjusting the makefile to match). This
1006 avoids the need to put extern "C" { ... } around #include "jpeglib.h" in
1007 your C++ application.
1010 Microsoft Windows, Microsoft Developer Studio:
1012 We include makefiles that should work as project files in DevStudio 4.2 or
1013 later. There is a library makefile that builds the IJG library as a static
1014 Win32 library, and an application makefile that builds the sample applications
1015 as Win32 console applications. (Even if you only want the library, we
1016 recommend building the applications so that you can run the self-test.)
1019 1. Copy jconfig.vc to jconfig.h, makelib.ds to jpeg.mak, and
1020 makeapps.ds to apps.mak. (Note that the renaming is critical!)
1021 2. Click on the .mak files to construct project workspaces.
1022 (If you are using DevStudio more recent than 4.2, you'll probably
1023 get a message saying that the makefiles are being updated.)
1024 3. Build the library project, then the applications project.
1025 4. Move the application .exe files from `app`\Release to an
1026 appropriate location on your path.
1027 5. To perform the self-test, execute the command line
1028 NMAKE /f makefile.vc test
1033 Watch out for optimization bugs in older Borland compilers; you may need
1034 to back off the optimization switch settings. See the comments in
1040 On some SGI systems, you may need to set "AR2= ar -ts" in the Makefile.
1041 If you are using configure, you can do this by saying
1042 ./configure RANLIB='ar -ts'
1043 This change is not needed on all SGIs. Use it only if the make fails at the
1044 stage of linking the completed programs.
1046 On the MIPS R4000 architecture (Indy, etc.), the compiler option "-mips2"
1047 reportedly speeds up the float DCT method substantially, enough to make it
1048 faster than the default int method (but still slower than the fast int
1049 method). If you use -mips2, you may want to alter the default DCT method to
1050 be float. To do this, put "#define JDCT_DEFAULT JDCT_FLOAT" in jconfig.h.
1055 On an Alpha/VMS system with MMS, be sure to use the "/Marco=Alpha=1"
1056 qualifier with MMS when building the JPEG package.
1058 VAX/VMS v5.5-1 may have problems with the test step of the build procedure
1059 reporting differences when it compares the original and test images. If the
1060 error points to the last block of the files, it is most likely bogus and may
1061 be safely ignored. It seems to be because the files are Stream_LF and
1062 Backup/Compare has difficulty with the (presumably) null padded files.
1063 This problem was not observed on VAX/VMS v6.1 or AXP/VMS v6.1.
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