#if !defined(_FX_JPEG_TURBO_) | |
/* | |
* 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; | |
} | |
#endif //_FX_JPEG_TURBO_ |