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144 lines
4.5 KiB
C
144 lines
4.5 KiB
C
/*
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* jccolext.c
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*
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* This file was part of the Independent JPEG Group's software:
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* Copyright (C) 1991-1996, Thomas G. Lane.
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* libjpeg-turbo Modifications:
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* Copyright (C) 2009-2012, 2015, D. R. Commander.
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* For conditions of distribution and use, see the accompanying README.ijg
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* file.
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*
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* This file contains input colorspace conversion routines.
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*/
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/* This file is included by jccolor.c */
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/*
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* Convert some rows of samples to the JPEG colorspace.
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*
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* Note that we change from the application's interleaved-pixel format
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* to our internal noninterleaved, one-plane-per-component format.
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* The input buffer is therefore three times as wide as the output buffer.
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*
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* A starting row offset is provided only for the output buffer. The caller
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* can easily adjust the passed input_buf value to accommodate any row
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* offset required on that side.
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*/
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INLINE
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LOCAL(void)
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rgb_ycc_convert_internal(j_compress_ptr cinfo, JSAMPARRAY input_buf,
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JSAMPIMAGE output_buf, JDIMENSION output_row,
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int num_rows)
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{
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my_cconvert_ptr cconvert = (my_cconvert_ptr)cinfo->cconvert;
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register int r, g, b;
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register JLONG *ctab = cconvert->rgb_ycc_tab;
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register JSAMPROW inptr;
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register JSAMPROW outptr0, outptr1, outptr2;
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register JDIMENSION col;
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JDIMENSION num_cols = cinfo->image_width;
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while (--num_rows >= 0) {
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inptr = *input_buf++;
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outptr0 = output_buf[0][output_row];
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outptr1 = output_buf[1][output_row];
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outptr2 = output_buf[2][output_row];
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output_row++;
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for (col = 0; col < num_cols; col++) {
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r = GETJSAMPLE(inptr[RGB_RED]);
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g = GETJSAMPLE(inptr[RGB_GREEN]);
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b = GETJSAMPLE(inptr[RGB_BLUE]);
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inptr += RGB_PIXELSIZE;
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/* If the inputs are 0..MAXJSAMPLE, the outputs of these equations
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* must be too; we do not need an explicit range-limiting operation.
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* Hence the value being shifted is never negative, and we don't
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* need the general RIGHT_SHIFT macro.
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*/
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/* Y */
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outptr0[col] = (JSAMPLE)((ctab[r + R_Y_OFF] + ctab[g + G_Y_OFF] +
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ctab[b + B_Y_OFF]) >> SCALEBITS);
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/* Cb */
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outptr1[col] = (JSAMPLE)((ctab[r + R_CB_OFF] + ctab[g + G_CB_OFF] +
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ctab[b + B_CB_OFF]) >> SCALEBITS);
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/* Cr */
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outptr2[col] = (JSAMPLE)((ctab[r + R_CR_OFF] + ctab[g + G_CR_OFF] +
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ctab[b + B_CR_OFF]) >> SCALEBITS);
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}
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}
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}
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/**************** Cases other than RGB -> YCbCr **************/
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/*
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* Convert some rows of samples to the JPEG colorspace.
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* This version handles RGB->grayscale conversion, which is the same
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* as the RGB->Y portion of RGB->YCbCr.
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* We assume rgb_ycc_start has been called (we only use the Y tables).
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*/
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INLINE
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LOCAL(void)
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rgb_gray_convert_internal(j_compress_ptr cinfo, JSAMPARRAY input_buf,
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JSAMPIMAGE output_buf, JDIMENSION output_row,
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int num_rows)
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{
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my_cconvert_ptr cconvert = (my_cconvert_ptr)cinfo->cconvert;
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register int r, g, b;
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register JLONG *ctab = cconvert->rgb_ycc_tab;
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register JSAMPROW inptr;
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register JSAMPROW outptr;
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register JDIMENSION col;
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JDIMENSION num_cols = cinfo->image_width;
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while (--num_rows >= 0) {
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inptr = *input_buf++;
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outptr = output_buf[0][output_row];
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output_row++;
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for (col = 0; col < num_cols; col++) {
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r = GETJSAMPLE(inptr[RGB_RED]);
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g = GETJSAMPLE(inptr[RGB_GREEN]);
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b = GETJSAMPLE(inptr[RGB_BLUE]);
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inptr += RGB_PIXELSIZE;
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/* Y */
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outptr[col] = (JSAMPLE)((ctab[r + R_Y_OFF] + ctab[g + G_Y_OFF] +
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ctab[b + B_Y_OFF]) >> SCALEBITS);
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}
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}
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}
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/*
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* Convert some rows of samples to the JPEG colorspace.
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* This version handles extended RGB->plain RGB conversion
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*/
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INLINE
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LOCAL(void)
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rgb_rgb_convert_internal(j_compress_ptr cinfo, JSAMPARRAY input_buf,
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JSAMPIMAGE output_buf, JDIMENSION output_row,
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int num_rows)
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{
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register JSAMPROW inptr;
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register JSAMPROW outptr0, outptr1, outptr2;
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register JDIMENSION col;
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JDIMENSION num_cols = cinfo->image_width;
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while (--num_rows >= 0) {
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inptr = *input_buf++;
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outptr0 = output_buf[0][output_row];
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outptr1 = output_buf[1][output_row];
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outptr2 = output_buf[2][output_row];
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output_row++;
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for (col = 0; col < num_cols; col++) {
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outptr0[col] = GETJSAMPLE(inptr[RGB_RED]);
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outptr1[col] = GETJSAMPLE(inptr[RGB_GREEN]);
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outptr2[col] = GETJSAMPLE(inptr[RGB_BLUE]);
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inptr += RGB_PIXELSIZE;
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}
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}
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}
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