+++ /dev/null
-/*
- * jccolor.c
- *
- * Copyright (C) 1991-1996, Thomas G. Lane.
- * 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 input colorspace conversion routines.
- */
-
-#define JPEG_INTERNALS
-#include "jinclude.h"
-#include "jpeglib.h"
-
-
-/* Private subobject */
-
-typedef struct {
- struct jpeg_color_converter pub; /* public fields */
-
- /* Private state for RGB->YCC conversion */
- INT32 * rgb_ycc_tab; /* => table for RGB to YCbCr conversion */
-} my_color_converter;
-
-typedef my_color_converter * my_cconvert_ptr;
-
-
-/**************** RGB -> YCbCr conversion: most common case **************/
-
-/*
- * YCbCr is defined per CCIR 601-1, except that Cb and Cr are
- * normalized to the range 0..MAXJSAMPLE rather than -0.5 .. 0.5.
- * The conversion equations to be implemented are therefore
- * Y = 0.29900 * R + 0.58700 * G + 0.11400 * B
- * Cb = -0.16874 * R - 0.33126 * G + 0.50000 * B + CENTERJSAMPLE
- * Cr = 0.50000 * R - 0.41869 * G - 0.08131 * B + CENTERJSAMPLE
- * (These numbers are derived from TIFF 6.0 section 21, dated 3-June-92.)
- * Note: older versions of the IJG code used a zero offset of MAXJSAMPLE/2,
- * rather than CENTERJSAMPLE, for Cb and Cr. This gave equal positive and
- * negative swings for Cb/Cr, but meant that grayscale values (Cb=Cr=0)
- * were not represented exactly. Now we sacrifice exact representation of
- * maximum red and maximum blue in order to get exact grayscales.
- *
- * 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.
- *
- * For even more speed, we avoid doing any multiplications in the inner loop
- * by precalculating the constants times R,G,B for all possible values.
- * For 8-bit JSAMPLEs this is very reasonable (only 256 entries per table);
- * for 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 CENTERJSAMPLE offsets and the rounding fudge-factor of 0.5 are included
- * in the tables to save adding them separately in the inner loop.
- */
-
-#define SCALEBITS 16 /* speediest right-shift on some machines */
-#define CBCR_OFFSET ((INT32) CENTERJSAMPLE << SCALEBITS)
-#define ONE_HALF ((INT32) 1 << (SCALEBITS-1))
-#define FIX(x) ((INT32) ((x) * (1L<<SCALEBITS) + 0.5))
-
-/* We allocate one big table and divide it up into eight parts, instead of
- * doing eight 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 eight 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 R_CB_OFF (3*(MAXJSAMPLE+1))
-#define G_CB_OFF (4*(MAXJSAMPLE+1))
-#define B_CB_OFF (5*(MAXJSAMPLE+1))
-#define R_CR_OFF B_CB_OFF /* B=>Cb, R=>Cr are the same */
-#define G_CR_OFF (6*(MAXJSAMPLE+1))
-#define B_CR_OFF (7*(MAXJSAMPLE+1))
-#define TABLE_SIZE (8*(MAXJSAMPLE+1))
-
-
-/*
- * Initialize for RGB->YCC colorspace conversion.
- */
-
-METHODDEF(void)
-rgb_ycc_start (j_compress_ptr cinfo)
-{
- my_cconvert_ptr cconvert = (my_cconvert_ptr) cinfo->cconvert;
- INT32 * rgb_ycc_tab;
- INT32 i;
-
- /* Allocate and fill in the conversion tables. */
- cconvert->rgb_ycc_tab = rgb_ycc_tab = (INT32 *)
- (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
- (TABLE_SIZE * SIZEOF(INT32)));
-
- for (i = 0; i <= MAXJSAMPLE; i++) {
- rgb_ycc_tab[i+R_Y_OFF] = FIX(0.29900) * i;
- rgb_ycc_tab[i+G_Y_OFF] = FIX(0.58700) * i;
- rgb_ycc_tab[i+B_Y_OFF] = FIX(0.11400) * i + ONE_HALF;
- rgb_ycc_tab[i+R_CB_OFF] = (-FIX(0.16874)) * i;
- rgb_ycc_tab[i+G_CB_OFF] = (-FIX(0.33126)) * i;
- /* We use a rounding fudge-factor of 0.5-epsilon for Cb and Cr.
- * This ensures that the maximum output will round to MAXJSAMPLE
- * not MAXJSAMPLE+1, and thus that we don't have to range-limit.
- */
- rgb_ycc_tab[i+B_CB_OFF] = FIX(0.50000) * i + CBCR_OFFSET + ONE_HALF-1;
-/* B=>Cb and R=>Cr tables are the same
- rgb_ycc_tab[i+R_CR_OFF] = FIX(0.50000) * i + CBCR_OFFSET + ONE_HALF-1;
-*/
- rgb_ycc_tab[i+G_CR_OFF] = (-FIX(0.41869)) * i;
- rgb_ycc_tab[i+B_CR_OFF] = (-FIX(0.08131)) * i;
- }
-}
-
-
-/*
- * Convert some rows of samples to the JPEG colorspace.
- *
- * Note that we change from the application's interleaved-pixel format
- * to our internal noninterleaved, one-plane-per-component format.
- * The input buffer is therefore three times as wide as the output buffer.
- *
- * A starting row offset is provided only for the output buffer. The caller
- * can easily adjust the passed input_buf value to accommodate any row
- * offset required on that side.
- */
-
-METHODDEF(void)
-rgb_ycc_convert (j_compress_ptr cinfo,
- JSAMPARRAY input_buf, JSAMPIMAGE output_buf,
- JDIMENSION output_row, int num_rows)
-{
- my_cconvert_ptr cconvert = (my_cconvert_ptr) cinfo->cconvert;
- register int r, g, b;
- register INT32 * ctab = cconvert->rgb_ycc_tab;
- register JSAMPROW inptr;
- register JSAMPROW outptr0, outptr1, outptr2;
- register JDIMENSION col;
- JDIMENSION num_cols = cinfo->image_width;
-
- while (--num_rows >= 0) {
- inptr = *input_buf++;
- outptr0 = output_buf[0][output_row];
- outptr1 = output_buf[1][output_row];
- outptr2 = output_buf[2][output_row];
- output_row++;
- for (col = 0; col < num_cols; col++) {
- r = GETJSAMPLE(inptr[RGB_RED]);
- g = GETJSAMPLE(inptr[RGB_GREEN]);
- b = GETJSAMPLE(inptr[RGB_BLUE]);
- inptr += RGB_PIXELSIZE;
- /* If the inputs are 0..MAXJSAMPLE, the outputs of these equations
- * must be too; we do not need an explicit range-limiting operation.
- * Hence the value being shifted is never negative, and we don't
- * need the general RIGHT_SHIFT macro.
- */
- /* Y */
- outptr0[col] = (JSAMPLE)
- ((ctab[r+R_Y_OFF] + ctab[g+G_Y_OFF] + ctab[b+B_Y_OFF])
- >> SCALEBITS);
- /* Cb */
- outptr1[col] = (JSAMPLE)
- ((ctab[r+R_CB_OFF] + ctab[g+G_CB_OFF] + ctab[b+B_CB_OFF])
- >> SCALEBITS);
- /* Cr */
- outptr2[col] = (JSAMPLE)
- ((ctab[r+R_CR_OFF] + ctab[g+G_CR_OFF] + ctab[b+B_CR_OFF])
- >> SCALEBITS);
- }
- }
-}
-
-
-/**************** Cases other than RGB -> YCbCr **************/
-
-
-/*
- * Convert some rows of samples to the JPEG colorspace.
- * This version handles RGB->grayscale conversion, which is the same
- * as the RGB->Y portion of RGB->YCbCr.
- * We assume rgb_ycc_start has been called (we only use the Y tables).
- */
-
-METHODDEF(void)
-rgb_gray_convert (j_compress_ptr cinfo,
- JSAMPARRAY input_buf, JSAMPIMAGE output_buf,
- JDIMENSION output_row, int num_rows)
-{
- my_cconvert_ptr cconvert = (my_cconvert_ptr) cinfo->cconvert;
- register int r, g, b;
- register INT32 * ctab = cconvert->rgb_ycc_tab;
- register JSAMPROW inptr;
- register JSAMPROW outptr;
- register JDIMENSION col;
- JDIMENSION num_cols = cinfo->image_width;
-
- while (--num_rows >= 0) {
- inptr = *input_buf++;
- outptr = output_buf[0][output_row];
- output_row++;
- for (col = 0; col < num_cols; col++) {
- r = GETJSAMPLE(inptr[RGB_RED]);
- g = GETJSAMPLE(inptr[RGB_GREEN]);
- b = GETJSAMPLE(inptr[RGB_BLUE]);
- inptr += RGB_PIXELSIZE;
- /* Y */
- outptr[col] = (JSAMPLE)
- ((ctab[r+R_Y_OFF] + ctab[g+G_Y_OFF] + ctab[b+B_Y_OFF])
- >> SCALEBITS);
- }
- }
-}
-
-
-/*
- * Convert some rows of samples to the JPEG colorspace.
- * This version handles Adobe-style CMYK->YCCK conversion,
- * where we convert R=1-C, G=1-M, and B=1-Y to YCbCr using the same
- * conversion as above, while passing K (black) unchanged.
- * We assume rgb_ycc_start has been called.
- */
-
-METHODDEF(void)
-cmyk_ycck_convert (j_compress_ptr cinfo,
- JSAMPARRAY input_buf, JSAMPIMAGE output_buf,
- JDIMENSION output_row, int num_rows)
-{
- my_cconvert_ptr cconvert = (my_cconvert_ptr) cinfo->cconvert;
- register int r, g, b;
- register INT32 * ctab = cconvert->rgb_ycc_tab;
- register JSAMPROW inptr;
- register JSAMPROW outptr0, outptr1, outptr2, outptr3;
- register JDIMENSION col;
- JDIMENSION num_cols = cinfo->image_width;
-
- while (--num_rows >= 0) {
- inptr = *input_buf++;
- outptr0 = output_buf[0][output_row];
- outptr1 = output_buf[1][output_row];
- outptr2 = output_buf[2][output_row];
- outptr3 = output_buf[3][output_row];
- output_row++;
- for (col = 0; col < num_cols; col++) {
- r = MAXJSAMPLE - GETJSAMPLE(inptr[0]);
- g = MAXJSAMPLE - GETJSAMPLE(inptr[1]);
- b = MAXJSAMPLE - GETJSAMPLE(inptr[2]);
- /* K passes through as-is */
- outptr3[col] = inptr[3]; /* don't need GETJSAMPLE here */
- inptr += 4;
- /* If the inputs are 0..MAXJSAMPLE, the outputs of these equations
- * must be too; we do not need an explicit range-limiting operation.
- * Hence the value being shifted is never negative, and we don't
- * need the general RIGHT_SHIFT macro.
- */
- /* Y */
- outptr0[col] = (JSAMPLE)
- ((ctab[r+R_Y_OFF] + ctab[g+G_Y_OFF] + ctab[b+B_Y_OFF])
- >> SCALEBITS);
- /* Cb */
- outptr1[col] = (JSAMPLE)
- ((ctab[r+R_CB_OFF] + ctab[g+G_CB_OFF] + ctab[b+B_CB_OFF])
- >> SCALEBITS);
- /* Cr */
- outptr2[col] = (JSAMPLE)
- ((ctab[r+R_CR_OFF] + ctab[g+G_CR_OFF] + ctab[b+B_CR_OFF])
- >> SCALEBITS);
- }
- }
-}
-
-
-/*
- * Convert some rows of samples to the JPEG colorspace.
- * This version handles grayscale output with no conversion.
- * The source can be either plain grayscale or YCbCr (since Y == gray).
- */
-
-METHODDEF(void)
-grayscale_convert (j_compress_ptr cinfo,
- JSAMPARRAY input_buf, JSAMPIMAGE output_buf,
- JDIMENSION output_row, int num_rows)
-{
- register JSAMPROW inptr;
- register JSAMPROW outptr;
- register JDIMENSION col;
- JDIMENSION num_cols = cinfo->image_width;
- int instride = cinfo->input_components;
-
- while (--num_rows >= 0) {
- inptr = *input_buf++;
- outptr = output_buf[0][output_row];
- output_row++;
- for (col = 0; col < num_cols; col++) {
- outptr[col] = inptr[0]; /* don't need GETJSAMPLE() here */
- inptr += instride;
- }
- }
-}
-
-
-/*
- * Convert some rows of samples to the JPEG colorspace.
- * This version handles multi-component colorspaces without conversion.
- * We assume input_components == num_components.
- */
-
-METHODDEF(void)
-null_convert (j_compress_ptr cinfo,
- JSAMPARRAY input_buf, JSAMPIMAGE output_buf,
- JDIMENSION output_row, int num_rows)
-{
- register JSAMPROW inptr;
- register JSAMPROW outptr;
- register JDIMENSION col;
- register int ci;
- int nc = cinfo->num_components;
- JDIMENSION num_cols = cinfo->image_width;
-
- while (--num_rows >= 0) {
- /* It seems fastest to make a separate pass for each component. */
- for (ci = 0; ci < nc; ci++) {
- inptr = *input_buf;
- outptr = output_buf[ci][output_row];
- for (col = 0; col < num_cols; col++) {
- outptr[col] = inptr[ci]; /* don't need GETJSAMPLE() here */
- inptr += nc;
- }
- }
- input_buf++;
- output_row++;
- }
-}
-
-
-/*
- * Empty method for start_pass.
- */
-
-METHODDEF(void)
-null_method (j_compress_ptr cinfo)
-{
- /* no work needed */
-}
-
-
-/*
- * Module initialization routine for input colorspace conversion.
- */
-
-GLOBAL(void)
-jinit_color_converter (j_compress_ptr cinfo)
-{
- my_cconvert_ptr cconvert;
-
- cconvert = (my_cconvert_ptr)
- (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
- SIZEOF(my_color_converter));
- cinfo->cconvert = (struct jpeg_color_converter *) cconvert;
- /* set start_pass to null method until we find out differently */
- cconvert->pub.start_pass = null_method;
-
- /* Make sure input_components agrees with in_color_space */
- switch (cinfo->in_color_space) {
- case JCS_GRAYSCALE:
- if (cinfo->input_components != 1)
- ERREXIT(cinfo, JERR_BAD_IN_COLORSPACE);
- break;
-
- case JCS_RGB:
-#if RGB_PIXELSIZE != 3
- if (cinfo->input_components != RGB_PIXELSIZE)
- ERREXIT(cinfo, JERR_BAD_IN_COLORSPACE);
- break;
-#endif /* else share code with YCbCr */
-
- case JCS_YCbCr:
- if (cinfo->input_components != 3)
- ERREXIT(cinfo, JERR_BAD_IN_COLORSPACE);
- break;
-
- case JCS_CMYK:
- case JCS_YCCK:
- if (cinfo->input_components != 4)
- ERREXIT(cinfo, JERR_BAD_IN_COLORSPACE);
- break;
-
- default: /* JCS_UNKNOWN can be anything */
- if (cinfo->input_components < 1)
- ERREXIT(cinfo, JERR_BAD_IN_COLORSPACE);
- break;
- }
-
- /* Check num_components, set conversion method based on requested space */
- switch (cinfo->jpeg_color_space) {
- case JCS_GRAYSCALE:
- if (cinfo->num_components != 1)
- ERREXIT(cinfo, JERR_BAD_J_COLORSPACE);
- if (cinfo->in_color_space == JCS_GRAYSCALE)
- cconvert->pub.color_convert = grayscale_convert;
- else if (cinfo->in_color_space == JCS_RGB) {
- cconvert->pub.start_pass = rgb_ycc_start;
- cconvert->pub.color_convert = rgb_gray_convert;
- } else if (cinfo->in_color_space == JCS_YCbCr)
- cconvert->pub.color_convert = grayscale_convert;
- else
- ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL);
- break;
-
- case JCS_RGB:
- if (cinfo->num_components != 3)
- ERREXIT(cinfo, JERR_BAD_J_COLORSPACE);
- if (cinfo->in_color_space == JCS_RGB && RGB_PIXELSIZE == 3)
- cconvert->pub.color_convert = null_convert;
- else
- ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL);
- break;
-
- case JCS_YCbCr:
- if (cinfo->num_components != 3)
- ERREXIT(cinfo, JERR_BAD_J_COLORSPACE);
- if (cinfo->in_color_space == JCS_RGB) {
- cconvert->pub.start_pass = rgb_ycc_start;
- cconvert->pub.color_convert = rgb_ycc_convert;
- } else if (cinfo->in_color_space == JCS_YCbCr)
- cconvert->pub.color_convert = null_convert;
- else
- ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL);
- break;
-
- case JCS_CMYK:
- if (cinfo->num_components != 4)
- ERREXIT(cinfo, JERR_BAD_J_COLORSPACE);
- if (cinfo->in_color_space == JCS_CMYK)
- cconvert->pub.color_convert = null_convert;
- else
- ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL);
- break;
-
- case JCS_YCCK:
- if (cinfo->num_components != 4)
- ERREXIT(cinfo, JERR_BAD_J_COLORSPACE);
- if (cinfo->in_color_space == JCS_CMYK) {
- cconvert->pub.start_pass = rgb_ycc_start;
- cconvert->pub.color_convert = cmyk_ycck_convert;
- } else if (cinfo->in_color_space == JCS_YCCK)
- cconvert->pub.color_convert = null_convert;
- else
- ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL);
- break;
-
- default: /* allow null conversion of JCS_UNKNOWN */
- if (cinfo->jpeg_color_space != cinfo->in_color_space ||
- cinfo->num_components != cinfo->input_components)
- ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL);
- cconvert->pub.color_convert = null_convert;
- break;
- }
-}
projects / reactos.git / blobdiff