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doom3-bfg/neo/libs/jpeg-6/jccolor.cpp
Robert Beckebans c2f45c550c Moved third-party libs to libs/
2012-11-27 21:26:06 +01:00

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/*
* jccolor.c
*
* Copyright (C) 1991-1994, 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;
}
}
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