forked from libjpeg-turbo/libjpeg-turbo
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jccolext.c
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/
jccolext.c
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/*
* jccolext.c
*
* This file was part of the Independent JPEG Group's software:
* Copyright (C) 1991-1996, Thomas G. Lane.
* libjpeg-turbo Modifications:
* Copyright (C) 2009-2012, 2015, 2022, D. R. Commander.
* For conditions of distribution and use, see the accompanying README.ijg
* file.
*
* This file contains input colorspace conversion routines.
*/
/* This file is included by jccolor.c */
/*
* 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.
*/
INLINE
LOCAL(void)
rgb_ycc_convert_internal(j_compress_ptr cinfo, _JSAMPARRAY input_buf,
_JSAMPIMAGE output_buf, JDIMENSION output_row,
int num_rows)
{
#if BITS_IN_JSAMPLE != 16
my_cconvert_ptr cconvert = (my_cconvert_ptr)cinfo->cconvert;
register int r, g, b;
register JLONG *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 = RANGE_LIMIT(inptr[RGB_RED]);
g = RANGE_LIMIT(inptr[RGB_GREEN]);
b = RANGE_LIMIT(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);
}
}
#else
ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL);
#endif
}
/**************** 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).
*/
INLINE
LOCAL(void)
rgb_gray_convert_internal(j_compress_ptr cinfo, _JSAMPARRAY input_buf,
_JSAMPIMAGE output_buf, JDIMENSION output_row,
int num_rows)
{
#if BITS_IN_JSAMPLE != 16
my_cconvert_ptr cconvert = (my_cconvert_ptr)cinfo->cconvert;
register int r, g, b;
register JLONG *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 = RANGE_LIMIT(inptr[RGB_RED]);
g = RANGE_LIMIT(inptr[RGB_GREEN]);
b = RANGE_LIMIT(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);
}
}
#else
ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL);
#endif
}
/*
* Convert some rows of samples to the JPEG colorspace.
* This version handles extended RGB->plain RGB conversion
*/
INLINE
LOCAL(void)
rgb_rgb_convert_internal(j_compress_ptr cinfo, _JSAMPARRAY input_buf,
_JSAMPIMAGE output_buf, JDIMENSION output_row,
int num_rows)
{
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++) {
outptr0[col] = inptr[RGB_RED];
outptr1[col] = inptr[RGB_GREEN];
outptr2[col] = inptr[RGB_BLUE];
inptr += RGB_PIXELSIZE;
}
}
}