зеркало из https://github.com/mozilla/pjs.git
105 строки
3.3 KiB
C
105 строки
3.3 KiB
C
/*
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* jdcolext.c
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*
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* Copyright (C) 1991-1997, Thomas G. Lane.
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* Copyright (C) 2009, 2011, D. R. Commander.
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* This file is part of the Independent JPEG Group's software.
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* For conditions of distribution and use, see the accompanying README file.
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*
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* This file contains output colorspace conversion routines.
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*/
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/* This file is included by jdcolor.c */
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/*
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* Convert some rows of samples to the output colorspace.
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*
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* Note that we change from noninterleaved, one-plane-per-component format
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* to interleaved-pixel format. The output buffer is therefore three times
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* as wide as the input buffer.
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* A starting row offset is provided only for the input buffer. The caller
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* can easily adjust the passed output_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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ycc_rgb_convert_internal (j_decompress_ptr cinfo,
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JSAMPIMAGE input_buf, JDIMENSION input_row,
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JSAMPARRAY output_buf, 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 y, cb, cr;
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register JSAMPROW outptr;
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register JSAMPROW inptr0, inptr1, inptr2;
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register JDIMENSION col;
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JDIMENSION num_cols = cinfo->output_width;
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/* copy these pointers into registers if possible */
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register JSAMPLE * range_limit = cinfo->sample_range_limit;
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register int * Crrtab = cconvert->Cr_r_tab;
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register int * Cbbtab = cconvert->Cb_b_tab;
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register INT32 * Crgtab = cconvert->Cr_g_tab;
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register INT32 * Cbgtab = cconvert->Cb_g_tab;
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SHIFT_TEMPS
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while (--num_rows >= 0) {
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inptr0 = input_buf[0][input_row];
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inptr1 = input_buf[1][input_row];
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inptr2 = input_buf[2][input_row];
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input_row++;
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outptr = *output_buf++;
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for (col = 0; col < num_cols; col++) {
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y = GETJSAMPLE(inptr0[col]);
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cb = GETJSAMPLE(inptr1[col]);
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cr = GETJSAMPLE(inptr2[col]);
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/* Range-limiting is essential due to noise introduced by DCT losses. */
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outptr[RGB_RED] = range_limit[y + Crrtab[cr]];
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outptr[RGB_GREEN] = range_limit[y +
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((int) RIGHT_SHIFT(Cbgtab[cb] + Crgtab[cr],
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SCALEBITS))];
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outptr[RGB_BLUE] = range_limit[y + Cbbtab[cb]];
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/* Set unused byte to 0xFF so it can be interpreted as an opaque */
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/* alpha channel value */
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#ifdef RGB_ALPHA
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outptr[RGB_ALPHA] = 0xFF;
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#endif
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outptr += RGB_PIXELSIZE;
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}
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}
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}
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/*
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* Convert grayscale to RGB: just duplicate the graylevel three times.
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* This is provided to support applications that don't want to cope
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* with grayscale as a separate case.
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*/
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INLINE
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LOCAL(void)
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gray_rgb_convert_internal (j_decompress_ptr cinfo,
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JSAMPIMAGE input_buf, JDIMENSION input_row,
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JSAMPARRAY output_buf, int num_rows)
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{
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register JSAMPROW inptr, outptr;
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register JDIMENSION col;
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JDIMENSION num_cols = cinfo->output_width;
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while (--num_rows >= 0) {
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inptr = input_buf[0][input_row++];
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outptr = *output_buf++;
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for (col = 0; col < num_cols; col++) {
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/* We can dispense with GETJSAMPLE() here */
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outptr[RGB_RED] = outptr[RGB_GREEN] = outptr[RGB_BLUE] = inptr[col];
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/* Set unused byte to 0xFF so it can be interpreted as an opaque */
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/* alpha channel value */
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#ifdef RGB_ALPHA
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outptr[RGB_ALPHA] = 0xFF;
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#endif
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outptr += RGB_PIXELSIZE;
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}
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}
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}
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