--- /dev/null
+/*
+ * jdcolor.c
+ *
+ * Copyright (C) 1991-1997, Thomas G. Lane.
+ * Modified 2011-2015 by Guido Vollbeding.
+ * This file is part of the Independent JPEG Group's software.
+ * For conditions of distribution and use, see the accompanying README file.
+ *
+ * This file contains output colorspace conversion routines.
+ */
+
+#define JPEG_INTERNALS
+#include "jinclude.h"
+#include "jpeglib.h"
+
+
+/* Private subobject */
+
+typedef struct {
+ struct jpeg_color_deconverter pub; /* public fields */
+
+ /* Private state for YCbCr->RGB and BG_YCC->RGB conversion */
+ int * Cr_r_tab; /* => table for Cr to R conversion */
+ int * Cb_b_tab; /* => table for Cb to B conversion */
+ INT32 * Cr_g_tab; /* => table for Cr to G conversion */
+ INT32 * Cb_g_tab; /* => table for Cb to G conversion */
+
+ /* Private state for RGB->Y conversion */
+ INT32 * rgb_y_tab; /* => table for RGB to Y conversion */
+} my_color_deconverter;
+
+typedef my_color_deconverter * my_cconvert_ptr;
+
+
+/*************** YCbCr -> RGB conversion: most common case **************/
+/*************** BG_YCC -> RGB conversion: less common case **************/
+/*************** RGB -> Y conversion: less common case **************/
+
+/*
+ * YCbCr is defined per Recommendation ITU-R BT.601-7 (03/2011),
+ * previously known as Recommendation CCIR 601-1, except that Cb and Cr
+ * are normalized to the range 0..MAXJSAMPLE rather than -0.5 .. 0.5.
+ * sRGB (standard RGB color space) is defined per IEC 61966-2-1:1999.
+ * sYCC (standard luma-chroma-chroma color space with extended gamut)
+ * is defined per IEC 61966-2-1:1999 Amendment A1:2003 Annex F.
+ * bg-sRGB and bg-sYCC (big gamut standard color spaces)
+ * are defined per IEC 61966-2-1:1999 Amendment A1:2003 Annex G.
+ * Note that the derived conversion coefficients given in some of these
+ * documents are imprecise. The general conversion equations are
+ *
+ * R = Y + K * (1 - Kr) * Cr
+ * G = Y - K * (Kb * (1 - Kb) * Cb + Kr * (1 - Kr) * Cr) / (1 - Kr - Kb)
+ * B = Y + K * (1 - Kb) * Cb
+ *
+ * Y = Kr * R + (1 - Kr - Kb) * G + Kb * B
+ *
+ * With Kr = 0.299 and Kb = 0.114 (derived according to SMPTE RP 177-1993
+ * from the 1953 FCC NTSC primaries and CIE Illuminant C), K = 2 for sYCC,
+ * the conversion equations to be implemented are therefore
+ *
+ * R = Y + 1.402 * Cr
+ * G = Y - 0.344136286 * Cb - 0.714136286 * Cr
+ * B = Y + 1.772 * Cb
+ *
+ * Y = 0.299 * R + 0.587 * G + 0.114 * B
+ *
+ * where Cb and Cr represent the incoming values less CENTERJSAMPLE.
+ * For bg-sYCC, with K = 4, the equations are
+ *
+ * R = Y + 2.804 * Cr
+ * G = Y - 0.688272572 * Cb - 1.428272572 * Cr
+ * B = Y + 3.544 * Cb
+ *
+ * To avoid floating-point arithmetic, we represent the fractional constants
+ * as integers scaled up by 2^16 (about 4 digits precision); we have to divide
+ * the products by 2^16, with appropriate rounding, to get the correct answer.
+ * Notice that Y, being an integral input, does not contribute any fraction
+ * so it need not participate in the rounding.
+ *
+ * For even more speed, we avoid doing any multiplications in the inner loop
+ * by precalculating the constants times Cb and Cr for all possible values.
+ * For 8-bit JSAMPLEs this is very reasonable (only 256 entries per table);
+ * for 9-bit to 12-bit samples it is still acceptable. It's not very
+ * reasonable for 16-bit samples, but if you want lossless storage you
+ * shouldn't be changing colorspace anyway.
+ * The Cr=>R and Cb=>B values can be rounded to integers in advance; the
+ * values for the G calculation are left scaled up, since we must add them
+ * together before rounding.
+ */
+
+#define SCALEBITS 16 /* speediest right-shift on some machines */
+#define ONE_HALF ((INT32) 1 << (SCALEBITS-1))
+#define FIX(x) ((INT32) ((x) * (1L<<SCALEBITS) + 0.5))
+
+/* We allocate one big table for RGB->Y conversion and divide it up into
+ * three parts, instead of doing three alloc_small requests. This lets us
+ * use a single table base address, which can be held in a register in the
+ * inner loops on many machines (more than can hold all three addresses,
+ * anyway).
+ */
+
+#define R_Y_OFF 0 /* offset to R => Y section */
+#define G_Y_OFF (1*(MAXJSAMPLE+1)) /* offset to G => Y section */
+#define B_Y_OFF (2*(MAXJSAMPLE+1)) /* etc. */
+#define TABLE_SIZE (3*(MAXJSAMPLE+1))
+
+
+/*
+ * Initialize tables for YCbCr->RGB and BG_YCC->RGB colorspace conversion.
+ */
+
+LOCAL(void)
+build_ycc_rgb_table (j_decompress_ptr cinfo)
+/* Normal case, sYCC */
+{
+ my_cconvert_ptr cconvert = (my_cconvert_ptr) cinfo->cconvert;
+ int i;
+ INT32 x;
+ SHIFT_TEMPS
+
+ cconvert->Cr_r_tab = (int *)
+ (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
+ (MAXJSAMPLE+1) * SIZEOF(int));
+ cconvert->Cb_b_tab = (int *)
+ (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
+ (MAXJSAMPLE+1) * SIZEOF(int));
+ cconvert->Cr_g_tab = (INT32 *)
+ (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
+ (MAXJSAMPLE+1) * SIZEOF(INT32));
+ cconvert->Cb_g_tab = (INT32 *)
+ (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
+ (MAXJSAMPLE+1) * SIZEOF(INT32));
+
+ for (i = 0, x = -CENTERJSAMPLE; i <= MAXJSAMPLE; i++, x++) {
+ /* i is the actual input pixel value, in the range 0..MAXJSAMPLE */
+ /* The Cb or Cr value we are thinking of is x = i - CENTERJSAMPLE */
+ /* Cr=>R value is nearest int to 1.402 * x */
+ cconvert->Cr_r_tab[i] = (int)
+ RIGHT_SHIFT(FIX(1.402) * x + ONE_HALF, SCALEBITS);
+ /* Cb=>B value is nearest int to 1.772 * x */
+ cconvert->Cb_b_tab[i] = (int)
+ RIGHT_SHIFT(FIX(1.772) * x + ONE_HALF, SCALEBITS);
+ /* Cr=>G value is scaled-up -0.714136286 * x */
+ cconvert->Cr_g_tab[i] = (- FIX(0.714136286)) * x;
+ /* Cb=>G value is scaled-up -0.344136286 * x */
+ /* We also add in ONE_HALF so that need not do it in inner loop */
+ cconvert->Cb_g_tab[i] = (- FIX(0.344136286)) * x + ONE_HALF;
+ }
+}
+
+
+LOCAL(void)
+build_bg_ycc_rgb_table (j_decompress_ptr cinfo)
+/* Wide gamut case, bg-sYCC */
+{
+ my_cconvert_ptr cconvert = (my_cconvert_ptr) cinfo->cconvert;
+ int i;
+ INT32 x;
+ SHIFT_TEMPS
+
+ cconvert->Cr_r_tab = (int *)
+ (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
+ (MAXJSAMPLE+1) * SIZEOF(int));
+ cconvert->Cb_b_tab = (int *)
+ (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
+ (MAXJSAMPLE+1) * SIZEOF(int));
+ cconvert->Cr_g_tab = (INT32 *)
+ (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
+ (MAXJSAMPLE+1) * SIZEOF(INT32));
+ cconvert->Cb_g_tab = (INT32 *)
+ (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
+ (MAXJSAMPLE+1) * SIZEOF(INT32));
+
+ for (i = 0, x = -CENTERJSAMPLE; i <= MAXJSAMPLE; i++, x++) {
+ /* i is the actual input pixel value, in the range 0..MAXJSAMPLE */
+ /* The Cb or Cr value we are thinking of is x = i - CENTERJSAMPLE */
+ /* Cr=>R value is nearest int to 2.804 * x */
+ cconvert->Cr_r_tab[i] = (int)
+ RIGHT_SHIFT(FIX(2.804) * x + ONE_HALF, SCALEBITS);
+ /* Cb=>B value is nearest int to 3.544 * x */
+ cconvert->Cb_b_tab[i] = (int)
+ RIGHT_SHIFT(FIX(3.544) * x + ONE_HALF, SCALEBITS);
+ /* Cr=>G value is scaled-up -1.428272572 * x */
+ cconvert->Cr_g_tab[i] = (- FIX(1.428272572)) * x;
+ /* Cb=>G value is scaled-up -0.688272572 * x */
+ /* We also add in ONE_HALF so that need not do it in inner loop */
+ cconvert->Cb_g_tab[i] = (- FIX(0.688272572)) * x + ONE_HALF;
+ }
+}
+
+
+/*
+ * Convert some rows of samples to the output colorspace.
+ *
+ * Note that we change from noninterleaved, one-plane-per-component format
+ * to interleaved-pixel format. The output buffer is therefore three times
+ * as wide as the input buffer.
+ * A starting row offset is provided only for the input buffer. The caller
+ * can easily adjust the passed output_buf value to accommodate any row
+ * offset required on that side.
+ */
+
+METHODDEF(void)
+ycc_rgb_convert (j_decompress_ptr cinfo,
+ JSAMPIMAGE input_buf, JDIMENSION input_row,
+ JSAMPARRAY output_buf, int num_rows)
+{
+ my_cconvert_ptr cconvert = (my_cconvert_ptr) cinfo->cconvert;
+ register int y, cb, cr;
+ register JSAMPROW outptr;
+ register JSAMPROW inptr0, inptr1, inptr2;
+ register JDIMENSION col;
+ JDIMENSION num_cols = cinfo->output_width;
+ /* copy these pointers into registers if possible */
+ register JSAMPLE * range_limit = cinfo->sample_range_limit;
+ register int * Crrtab = cconvert->Cr_r_tab;
+ register int * Cbbtab = cconvert->Cb_b_tab;
+ register INT32 * Crgtab = cconvert->Cr_g_tab;
+ register INT32 * Cbgtab = cconvert->Cb_g_tab;
+ SHIFT_TEMPS
+
+ while (--num_rows >= 0) {
+ inptr0 = input_buf[0][input_row];
+ inptr1 = input_buf[1][input_row];
+ inptr2 = input_buf[2][input_row];
+ input_row++;
+ outptr = *output_buf++;
+ for (col = 0; col < num_cols; col++) {
+ y = GETJSAMPLE(inptr0[col]);
+ cb = GETJSAMPLE(inptr1[col]);
+ cr = GETJSAMPLE(inptr2[col]);
+ /* Range-limiting is essential due to noise introduced by DCT losses,
+ * for extended gamut (sYCC) and wide gamut (bg-sYCC) encodings.
+ */
+ outptr[RGB_RED] = range_limit[y + Crrtab[cr]];
+ outptr[RGB_GREEN] = range_limit[y +
+ ((int) RIGHT_SHIFT(Cbgtab[cb] + Crgtab[cr],
+ SCALEBITS))];
+ outptr[RGB_BLUE] = range_limit[y + Cbbtab[cb]];
+ outptr += RGB_PIXELSIZE;
+ }
+ }
+}
+
+
+/**************** Cases other than YCC -> RGB ****************/
+
+
+/*
+ * Initialize for RGB->grayscale colorspace conversion.
+ */
+
+LOCAL(void)
+build_rgb_y_table (j_decompress_ptr cinfo)
+{
+ my_cconvert_ptr cconvert = (my_cconvert_ptr) cinfo->cconvert;
+ INT32 * rgb_y_tab;
+ INT32 i;
+
+ /* Allocate and fill in the conversion tables. */
+ cconvert->rgb_y_tab = rgb_y_tab = (INT32 *)
+ (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
+ (TABLE_SIZE * SIZEOF(INT32)));
+
+ for (i = 0; i <= MAXJSAMPLE; i++) {
+ rgb_y_tab[i+R_Y_OFF] = FIX(0.299) * i;
+ rgb_y_tab[i+G_Y_OFF] = FIX(0.587) * i;
+ rgb_y_tab[i+B_Y_OFF] = FIX(0.114) * i + ONE_HALF;
+ }
+}
+
+
+/*
+ * Convert RGB to grayscale.
+ */
+
+METHODDEF(void)
+rgb_gray_convert (j_decompress_ptr cinfo,
+ JSAMPIMAGE input_buf, JDIMENSION input_row,
+ JSAMPARRAY output_buf, int num_rows)
+{
+ my_cconvert_ptr cconvert = (my_cconvert_ptr) cinfo->cconvert;
+ register INT32 * ctab = cconvert->rgb_y_tab;
+ register int r, g, b;
+ register JSAMPROW outptr;
+ register JSAMPROW inptr0, inptr1, inptr2;
+ register JDIMENSION col;
+ JDIMENSION num_cols = cinfo->output_width;
+
+ while (--num_rows >= 0) {
+ inptr0 = input_buf[0][input_row];
+ inptr1 = input_buf[1][input_row];
+ inptr2 = input_buf[2][input_row];
+ input_row++;
+ outptr = *output_buf++;
+ for (col = 0; col < num_cols; col++) {
+ r = GETJSAMPLE(inptr0[col]);
+ g = GETJSAMPLE(inptr1[col]);
+ b = GETJSAMPLE(inptr2[col]);
+ /* Y */
+ outptr[col] = (JSAMPLE)
+ ((ctab[r+R_Y_OFF] + ctab[g+G_Y_OFF] + ctab[b+B_Y_OFF])
+ >> SCALEBITS);
+ }
+ }
+}
+
+
+/*
+ * [R-G,G,B-G] to [R,G,B] conversion with modulo calculation
+ * (inverse color transform).
+ * This can be seen as an adaption of the general YCbCr->RGB
+ * conversion equation with Kr = Kb = 0, while replacing the
+ * normalization by modulo calculation.
+ */
+
+METHODDEF(void)
+rgb1_rgb_convert (j_decompress_ptr cinfo,
+ JSAMPIMAGE input_buf, JDIMENSION input_row,
+ JSAMPARRAY output_buf, int num_rows)
+{
+ register int r, g, b;
+ register JSAMPROW outptr;
+ register JSAMPROW inptr0, inptr1, inptr2;
+ register JDIMENSION col;
+ JDIMENSION num_cols = cinfo->output_width;
+
+ while (--num_rows >= 0) {
+ inptr0 = input_buf[0][input_row];
+ inptr1 = input_buf[1][input_row];
+ inptr2 = input_buf[2][input_row];
+ input_row++;
+ outptr = *output_buf++;
+ for (col = 0; col < num_cols; col++) {
+ r = GETJSAMPLE(inptr0[col]);
+ g = GETJSAMPLE(inptr1[col]);
+ b = GETJSAMPLE(inptr2[col]);
+ /* Assume that MAXJSAMPLE+1 is a power of 2, so that the MOD
+ * (modulo) operator is equivalent to the bitmask operator AND.
+ */
+ outptr[RGB_RED] = (JSAMPLE) ((r + g - CENTERJSAMPLE) & MAXJSAMPLE);
+ outptr[RGB_GREEN] = (JSAMPLE) g;
+ outptr[RGB_BLUE] = (JSAMPLE) ((b + g - CENTERJSAMPLE) & MAXJSAMPLE);
+ outptr += RGB_PIXELSIZE;
+ }
+ }
+}
+
+
+/*
+ * [R-G,G,B-G] to grayscale conversion with modulo calculation
+ * (inverse color transform).
+ */
+
+METHODDEF(void)
+rgb1_gray_convert (j_decompress_ptr cinfo,
+ JSAMPIMAGE input_buf, JDIMENSION input_row,
+ JSAMPARRAY output_buf, int num_rows)
+{
+ my_cconvert_ptr cconvert = (my_cconvert_ptr) cinfo->cconvert;
+ register INT32 * ctab = cconvert->rgb_y_tab;
+ register int r, g, b;
+ register JSAMPROW outptr;
+ register JSAMPROW inptr0, inptr1, inptr2;
+ register JDIMENSION col;
+ JDIMENSION num_cols = cinfo->output_width;
+
+ while (--num_rows >= 0) {
+ inptr0 = input_buf[0][input_row];
+ inptr1 = input_buf[1][input_row];
+ inptr2 = input_buf[2][input_row];
+ input_row++;
+ outptr = *output_buf++;
+ for (col = 0; col < num_cols; col++) {
+ r = GETJSAMPLE(inptr0[col]);
+ g = GETJSAMPLE(inptr1[col]);
+ b = GETJSAMPLE(inptr2[col]);
+ /* Assume that MAXJSAMPLE+1 is a power of 2, so that the MOD
+ * (modulo) operator is equivalent to the bitmask operator AND.
+ */
+ r = (r + g - CENTERJSAMPLE) & MAXJSAMPLE;
+ b = (b + g - CENTERJSAMPLE) & MAXJSAMPLE;
+ /* Y */
+ outptr[col] = (JSAMPLE)
+ ((ctab[r+R_Y_OFF] + ctab[g+G_Y_OFF] + ctab[b+B_Y_OFF])
+ >> SCALEBITS);
+ }
+ }
+}
+
+
+/*
+ * No colorspace change, but conversion from separate-planes
+ * to interleaved representation.
+ */
+
+METHODDEF(void)
+rgb_convert (j_decompress_ptr cinfo,
+ JSAMPIMAGE input_buf, JDIMENSION input_row,
+ JSAMPARRAY output_buf, int num_rows)
+{
+ register JSAMPROW outptr;
+ register JSAMPROW inptr0, inptr1, inptr2;
+ register JDIMENSION col;
+ JDIMENSION num_cols = cinfo->output_width;
+
+ while (--num_rows >= 0) {
+ inptr0 = input_buf[0][input_row];
+ inptr1 = input_buf[1][input_row];
+ inptr2 = input_buf[2][input_row];
+ input_row++;
+ outptr = *output_buf++;
+ for (col = 0; col < num_cols; col++) {
+ /* We can dispense with GETJSAMPLE() here */
+ outptr[RGB_RED] = inptr0[col];
+ outptr[RGB_GREEN] = inptr1[col];
+ outptr[RGB_BLUE] = inptr2[col];
+ outptr += RGB_PIXELSIZE;
+ }
+ }
+}
+
+
+/*
+ * Color conversion for no colorspace change: just copy the data,
+ * converting from separate-planes to interleaved representation.
+ */
+
+METHODDEF(void)
+null_convert (j_decompress_ptr cinfo,
+ JSAMPIMAGE input_buf, JDIMENSION input_row,
+ JSAMPARRAY output_buf, int num_rows)
+{
+ int ci;
+ register int nc = cinfo->num_components;
+ register JSAMPROW outptr;
+ register JSAMPROW inptr;
+ register JDIMENSION col;
+ JDIMENSION num_cols = cinfo->output_width;
+
+ while (--num_rows >= 0) {
+ for (ci = 0; ci < nc; ci++) {
+ inptr = input_buf[ci][input_row];
+ outptr = output_buf[0] + ci;
+ for (col = 0; col < num_cols; col++) {
+ *outptr = *inptr++; /* needn't bother with GETJSAMPLE() here */
+ outptr += nc;
+ }
+ }
+ input_row++;
+ output_buf++;
+ }
+}
+
+
+/*
+ * Color conversion for grayscale: just copy the data.
+ * This also works for YCC -> grayscale conversion, in which
+ * we just copy the Y (luminance) component and ignore chrominance.
+ */
+
+METHODDEF(void)
+grayscale_convert (j_decompress_ptr cinfo,
+ JSAMPIMAGE input_buf, JDIMENSION input_row,
+ JSAMPARRAY output_buf, int num_rows)
+{
+ jcopy_sample_rows(input_buf[0], (int) input_row, output_buf, 0,
+ num_rows, cinfo->output_width);
+}
+
+
+/*
+ * Convert grayscale to RGB: just duplicate the graylevel three times.
+ * This is provided to support applications that don't want to cope
+ * with grayscale as a separate case.
+ */
+
+METHODDEF(void)
+gray_rgb_convert (j_decompress_ptr cinfo,
+ JSAMPIMAGE input_buf, JDIMENSION input_row,
+ JSAMPARRAY output_buf, int num_rows)
+{
+ register JSAMPROW outptr;
+ register JSAMPROW inptr;
+ register JDIMENSION col;
+ JDIMENSION num_cols = cinfo->output_width;
+
+ while (--num_rows >= 0) {
+ inptr = input_buf[0][input_row++];
+ outptr = *output_buf++;
+ for (col = 0; col < num_cols; col++) {
+ /* We can dispense with GETJSAMPLE() here */
+ outptr[RGB_RED] = outptr[RGB_GREEN] = outptr[RGB_BLUE] = inptr[col];
+ outptr += RGB_PIXELSIZE;
+ }
+ }
+}
+
+
+/*
+ * Adobe-style YCCK->CMYK conversion.
+ * We convert YCbCr to R=1-C, G=1-M, and B=1-Y using the same
+ * conversion as above, while passing K (black) unchanged.
+ * We assume build_ycc_rgb_table has been called.
+ */
+
+METHODDEF(void)
+ycck_cmyk_convert (j_decompress_ptr cinfo,
+ JSAMPIMAGE input_buf, JDIMENSION input_row,
+ JSAMPARRAY output_buf, int num_rows)
+{
+ my_cconvert_ptr cconvert = (my_cconvert_ptr) cinfo->cconvert;
+ register int y, cb, cr;
+ register JSAMPROW outptr;
+ register JSAMPROW inptr0, inptr1, inptr2, inptr3;
+ register JDIMENSION col;
+ JDIMENSION num_cols = cinfo->output_width;
+ /* copy these pointers into registers if possible */
+ register JSAMPLE * range_limit = cinfo->sample_range_limit;
+ register int * Crrtab = cconvert->Cr_r_tab;
+ register int * Cbbtab = cconvert->Cb_b_tab;
+ register INT32 * Crgtab = cconvert->Cr_g_tab;
+ register INT32 * Cbgtab = cconvert->Cb_g_tab;
+ SHIFT_TEMPS
+
+ while (--num_rows >= 0) {
+ inptr0 = input_buf[0][input_row];
+ inptr1 = input_buf[1][input_row];
+ inptr2 = input_buf[2][input_row];
+ inptr3 = input_buf[3][input_row];
+ input_row++;
+ outptr = *output_buf++;
+ for (col = 0; col < num_cols; col++) {
+ y = GETJSAMPLE(inptr0[col]);
+ cb = GETJSAMPLE(inptr1[col]);
+ cr = GETJSAMPLE(inptr2[col]);
+ /* Range-limiting is essential due to noise introduced by DCT losses,
+ * and for extended gamut encodings (sYCC).
+ */
+ outptr[0] = range_limit[MAXJSAMPLE - (y + Crrtab[cr])]; /* red */
+ outptr[1] = range_limit[MAXJSAMPLE - (y + /* green */
+ ((int) RIGHT_SHIFT(Cbgtab[cb] + Crgtab[cr],
+ SCALEBITS)))];
+ outptr[2] = range_limit[MAXJSAMPLE - (y + Cbbtab[cb])]; /* blue */
+ /* K passes through unchanged */
+ outptr[3] = inptr3[col]; /* don't need GETJSAMPLE here */
+ outptr += 4;
+ }
+ }
+}
+
+
+/*
+ * Empty method for start_pass.
+ */
+
+METHODDEF(void)
+start_pass_dcolor (j_decompress_ptr cinfo)
+{
+ /* no work needed */
+}
+
+
+/*
+ * Module initialization routine for output colorspace conversion.
+ */
+
+GLOBAL(void)
+jinit_color_deconverter (j_decompress_ptr cinfo)
+{
+ my_cconvert_ptr cconvert;
+ int ci;
+
+ cconvert = (my_cconvert_ptr)
+ (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
+ SIZEOF(my_color_deconverter));
+ cinfo->cconvert = &cconvert->pub;
+ cconvert->pub.start_pass = start_pass_dcolor;
+
+ /* Make sure num_components agrees with jpeg_color_space */
+ switch (cinfo->jpeg_color_space) {
+ case JCS_GRAYSCALE:
+ if (cinfo->num_components != 1)
+ ERREXIT(cinfo, JERR_BAD_J_COLORSPACE);
+ break;
+
+ case JCS_RGB:
+ case JCS_YCbCr:
+ case JCS_BG_RGB:
+ case JCS_BG_YCC:
+ if (cinfo->num_components != 3)
+ ERREXIT(cinfo, JERR_BAD_J_COLORSPACE);
+ break;
+
+ case JCS_CMYK:
+ case JCS_YCCK:
+ if (cinfo->num_components != 4)
+ ERREXIT(cinfo, JERR_BAD_J_COLORSPACE);
+ break;
+
+ default: /* JCS_UNKNOWN can be anything */
+ if (cinfo->num_components < 1)
+ ERREXIT(cinfo, JERR_BAD_J_COLORSPACE);
+ break;
+ }
+
+ /* Support color transform only for RGB colorspaces */
+ if (cinfo->color_transform &&
+ cinfo->jpeg_color_space != JCS_RGB &&
+ cinfo->jpeg_color_space != JCS_BG_RGB)
+ ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL);
+
+ /* Set out_color_components and conversion method based on requested space.
+ * Also clear the component_needed flags for any unused components,
+ * so that earlier pipeline stages can avoid useless computation.
+ */
+
+ switch (cinfo->out_color_space) {
+ case JCS_GRAYSCALE:
+ cinfo->out_color_components = 1;
+ switch (cinfo->jpeg_color_space) {
+ case JCS_GRAYSCALE:
+ case JCS_YCbCr:
+ case JCS_BG_YCC:
+ cconvert->pub.color_convert = grayscale_convert;
+ /* For color->grayscale conversion, only the Y (0) component is needed */
+ for (ci = 1; ci < cinfo->num_components; ci++)
+ cinfo->comp_info[ci].component_needed = FALSE;
+ break;
+ case JCS_RGB:
+ switch (cinfo->color_transform) {
+ case JCT_NONE:
+ cconvert->pub.color_convert = rgb_gray_convert;
+ break;
+ case JCT_SUBTRACT_GREEN:
+ cconvert->pub.color_convert = rgb1_gray_convert;
+ break;
+ default:
+ ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL);
+ }
+ build_rgb_y_table(cinfo);
+ break;
+ default:
+ ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL);
+ }
+ break;
+
+ case JCS_RGB:
+ cinfo->out_color_components = RGB_PIXELSIZE;
+ switch (cinfo->jpeg_color_space) {
+ case JCS_GRAYSCALE:
+ cconvert->pub.color_convert = gray_rgb_convert;
+ break;
+ case JCS_YCbCr:
+ cconvert->pub.color_convert = ycc_rgb_convert;
+ build_ycc_rgb_table(cinfo);
+ break;
+ case JCS_BG_YCC:
+ cconvert->pub.color_convert = ycc_rgb_convert;
+ build_bg_ycc_rgb_table(cinfo);
+ break;
+ case JCS_RGB:
+ switch (cinfo->color_transform) {
+ case JCT_NONE:
+ cconvert->pub.color_convert = rgb_convert;
+ break;
+ case JCT_SUBTRACT_GREEN:
+ cconvert->pub.color_convert = rgb1_rgb_convert;
+ break;
+ default:
+ ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL);
+ }
+ break;
+ default:
+ ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL);
+ }
+ break;
+
+ case JCS_BG_RGB:
+ cinfo->out_color_components = RGB_PIXELSIZE;
+ if (cinfo->jpeg_color_space == JCS_BG_RGB) {
+ switch (cinfo->color_transform) {
+ case JCT_NONE:
+ cconvert->pub.color_convert = rgb_convert;
+ break;
+ case JCT_SUBTRACT_GREEN:
+ cconvert->pub.color_convert = rgb1_rgb_convert;
+ break;
+ default:
+ ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL);
+ }
+ } else
+ ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL);
+ break;
+
+ case JCS_CMYK:
+ cinfo->out_color_components = 4;
+ switch (cinfo->jpeg_color_space) {
+ case JCS_YCCK:
+ cconvert->pub.color_convert = ycck_cmyk_convert;
+ build_ycc_rgb_table(cinfo);
+ break;
+ case JCS_CMYK:
+ cconvert->pub.color_convert = null_convert;
+ break;
+ default:
+ ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL);
+ }
+ break;
+
+ default:
+ /* Permit null conversion to same output space */
+ if (cinfo->out_color_space == cinfo->jpeg_color_space) {
+ cinfo->out_color_components = cinfo->num_components;
+ cconvert->pub.color_convert = null_convert;
+ } else /* unsupported non-null conversion */
+ ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL);
+ break;
+ }
+
+ if (cinfo->quantize_colors)
+ cinfo->output_components = 1; /* single colormapped output component */
+ else
+ cinfo->output_components = cinfo->out_color_components;
+}
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