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raze/libraries/jpeg/jdcolor.c
Christoph Oelckers 718112a8fe - added external libraries for music format playback and decompression from GZDoom. 
Currently none of these is being used, but eventually they will, once more code gets ported over.
So it's better to have them right away and avoid editing the project file too much, only to revert that later.
2019-09-22 08:59:48 +02:00

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/*
* jdcolor.c
*
* Copyright (C) 1991-1997, Thomas G. Lane.
* Modified 2011-2017 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"
#if RANGE_BITS < 2
/* Deliberate syntax err */
Sorry, this code requires 2 or more range extension bits.
#endif
/* 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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