+++ /dev/null
-/*
- * jdcolor.c
- *
- * Copyright (C) 1991-1997, 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 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 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 */
-} my_color_deconverter;
-
-typedef my_color_deconverter * my_cconvert_ptr;
-
-
-/**************** YCbCr -> RGB 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
- * R = Y + 1.40200 * Cr
- * G = Y - 0.34414 * Cb - 0.71414 * Cr
- * B = Y + 1.77200 * Cb
- * where Cb and Cr represent the incoming values less CENTERJSAMPLE.
- * (These numbers are derived from TIFF 6.0 section 21, dated 3-June-92.)
- *
- * 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 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))
-
-
-/*
- * Initialize tables for YCC->RGB colorspace conversion.
- */
-
-LOCAL(void)
-build_ycc_rgb_table (j_decompress_ptr cinfo)
-{
- 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 1.40200 * x */
- cconvert->Cr_r_tab[i] = (int)
- RIGHT_SHIFT(FIX(1.40200) * x + ONE_HALF, SCALEBITS);
- /* Cb=>B value is nearest int to 1.77200 * x */
- cconvert->Cb_b_tab[i] = (int)
- RIGHT_SHIFT(FIX(1.77200) * x + ONE_HALF, SCALEBITS);
- /* Cr=>G value is scaled-up -0.71414 * x */
- cconvert->Cr_g_tab[i] = (- FIX(0.71414)) * x;
- /* Cb=>G value is scaled-up -0.34414 * x */
- /* We also add in ONE_HALF so that need not do it in inner loop */
- cconvert->Cb_g_tab[i] = (- FIX(0.34414)) * 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. */
- 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 YCbCr -> RGB **************/
-
-
-/*
- * 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)
-{
- register JSAMPROW inptr, outptr;
- register JDIMENSION count;
- register int num_components = cinfo->num_components;
- JDIMENSION num_cols = cinfo->output_width;
- int ci;
-
- while (--num_rows >= 0) {
- for (ci = 0; ci < num_components; ci++) {
- inptr = input_buf[ci][input_row];
- outptr = output_buf[0] + ci;
- for (count = num_cols; count > 0; count--) {
- *outptr = *inptr++; /* needn't bother with GETJSAMPLE() here */
- outptr += num_components;
- }
- }
- input_row++;
- output_buf++;
- }
-}
-
-
-/*
- * Color conversion for grayscale: just copy the data.
- * This also works for YCbCr -> 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 inptr, outptr;
- 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. */
- 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 = (struct jpeg_color_deconverter *) cconvert;
- 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:
- 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;
- }
-
- /* 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;
- if (cinfo->jpeg_color_space == JCS_GRAYSCALE ||
- cinfo->jpeg_color_space == JCS_YCbCr) {
- 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;
- } else
- ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL);
- break;
-
- case JCS_RGB:
- cinfo->out_color_components = RGB_PIXELSIZE;
- if (cinfo->jpeg_color_space == JCS_YCbCr) {
- cconvert->pub.color_convert = ycc_rgb_convert;
- build_ycc_rgb_table(cinfo);
- } else if (cinfo->jpeg_color_space == JCS_GRAYSCALE) {
- cconvert->pub.color_convert = gray_rgb_convert;
- } else if (cinfo->jpeg_color_space == JCS_RGB && RGB_PIXELSIZE == 3) {
- cconvert->pub.color_convert = null_convert;
- } else
- ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL);
- break;
-
- case JCS_CMYK:
- cinfo->out_color_components = 4;
- if (cinfo->jpeg_color_space == JCS_YCCK) {
- cconvert->pub.color_convert = ycck_cmyk_convert;
- build_ycc_rgb_table(cinfo);
- } else if (cinfo->jpeg_color_space == JCS_CMYK) {
- cconvert->pub.color_convert = null_convert;
- } else
- 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;
-}
projects / reactos.git / blobdiff