media/libjpeg/jdcolext.c

   1 /*
   2  * jdcolext.c
   3  *
   4  * This file was part of the Independent JPEG Group's software:
   5  * Copyright (C) 1991-1997, Thomas G. Lane.
   6  * libjpeg-turbo Modifications:
   7  * Copyright (C) 2009, 2011, D. R. Commander.
   8  * For conditions of distribution and use, see the accompanying README file.
   9  *
  10  * This file contains output colorspace conversion routines.
  11  */
  12
  13
  14 /* This file is included by jdcolor.c */
  15
  16
  17 /*
  18  * Convert some rows of samples to the output colorspace.
  19  *
  20  * Note that we change from noninterleaved, one-plane-per-component format
  21  * to interleaved-pixel format.  The output buffer is therefore three times
  22  * as wide as the input buffer.
  23  * A starting row offset is provided only for the input buffer.  The caller
  24  * can easily adjust the passed output_buf value to accommodate any row
  25  * offset required on that side.
  26  */
  27
  28 INLINE
  29 LOCAL(void)
  30 ycc_rgb_convert_internal (j_decompress_ptr cinfo,
  31                           JSAMPIMAGE input_buf, JDIMENSION input_row,
  32                           JSAMPARRAY output_buf, int num_rows)
  33 {
  34   my_cconvert_ptr cconvert = (my_cconvert_ptr) cinfo->cconvert;
  35   register int y, cb, cr;
  36   register JSAMPROW outptr;
  37   register JSAMPROW inptr0, inptr1, inptr2;
  38   register JDIMENSION col;
  39   JDIMENSION num_cols = cinfo->output_width;
  40   /* copy these pointers into registers if possible */
  41   register JSAMPLE * range_limit = cinfo->sample_range_limit;
  42   register int * Crrtab = cconvert->Cr_r_tab;
  43   register int * Cbbtab = cconvert->Cb_b_tab;
  44   register INT32 * Crgtab = cconvert->Cr_g_tab;
  45   register INT32 * Cbgtab = cconvert->Cb_g_tab;
  46   SHIFT_TEMPS
  47
  48   while (--num_rows >= 0) {
  49     inptr0 = input_buf[0][input_row];
  50     inptr1 = input_buf[1][input_row];
  51     inptr2 = input_buf[2][input_row];
  52     input_row++;
  53     outptr = *output_buf++;
  54     for (col = 0; col < num_cols; col++) {
  55       y  = GETJSAMPLE(inptr0[col]);
  56       cb = GETJSAMPLE(inptr1[col]);
  57       cr = GETJSAMPLE(inptr2[col]);
  58       /* Range-limiting is essential due to noise introduced by DCT losses. */
  59       outptr[RGB_RED] =   range_limit[y + Crrtab[cr]];
  60       outptr[RGB_GREEN] = range_limit[y +
  61                               ((int) RIGHT_SHIFT(Cbgtab[cb] + Crgtab[cr],
  62                                                  SCALEBITS))];
  63       outptr[RGB_BLUE] =  range_limit[y + Cbbtab[cb]];
  64       /* Set unused byte to 0xFF so it can be interpreted as an opaque */
  65       /* alpha channel value */
  66 #ifdef RGB_ALPHA
  67       outptr[RGB_ALPHA] = 0xFF;
  68 #endif
  69       outptr += RGB_PIXELSIZE;
  70     }
  71   }
  72 }
  73
  74
  75 /*
  76  * Convert grayscale to RGB: just duplicate the graylevel three times.
  77  * This is provided to support applications that don't want to cope
  78  * with grayscale as a separate case.
  79  */
  80
  81 INLINE
  82 LOCAL(void)
  83 gray_rgb_convert_internal (j_decompress_ptr cinfo,
  84                            JSAMPIMAGE input_buf, JDIMENSION input_row,
  85                            JSAMPARRAY output_buf, int num_rows)
  86 {
  87   register JSAMPROW inptr, outptr;
  88   register JDIMENSION col;
  89   JDIMENSION num_cols = cinfo->output_width;
  90
  91   while (--num_rows >= 0) {
  92     inptr = input_buf[0][input_row++];
  93     outptr = *output_buf++;
  94     for (col = 0; col < num_cols; col++) {
  95       /* We can dispense with GETJSAMPLE() here */
  96       outptr[RGB_RED] = outptr[RGB_GREEN] = outptr[RGB_BLUE] = inptr[col];
  97       /* Set unused byte to 0xFF so it can be interpreted as an opaque */
  98       /* alpha channel value */
  99 #ifdef RGB_ALPHA
 100       outptr[RGB_ALPHA] = 0xFF;
 101 #endif
 102       outptr += RGB_PIXELSIZE;
 103     }
 104   }
 105 }
 106
 107
 108 /*
 109  * Convert RGB to extended RGB: just swap the order of source pixels
 110  */
 111
 112 INLINE
 113 LOCAL(void)
 114 rgb_rgb_convert_internal (j_decompress_ptr cinfo,
 115                           JSAMPIMAGE input_buf, JDIMENSION input_row,
 116                           JSAMPARRAY output_buf, int num_rows)
 117 {
 118   register JSAMPROW inptr0, inptr1, inptr2;
 119   register JSAMPROW outptr;
 120   register JDIMENSION col;
 121   JDIMENSION num_cols = cinfo->output_width;
 122
 123   while (--num_rows >= 0) {
 124     inptr0 = input_buf[0][input_row];
 125     inptr1 = input_buf[1][input_row];
 126     inptr2 = input_buf[2][input_row];
 127     input_row++;
 128     outptr = *output_buf++;
 129     for (col = 0; col < num_cols; col++) {
 130       /* We can dispense with GETJSAMPLE() here */
 131       outptr[RGB_RED] = inptr0[col];
 132       outptr[RGB_GREEN] = inptr1[col];
 133       outptr[RGB_BLUE] = inptr2[col];
 134       /* Set unused byte to 0xFF so it can be interpreted as an opaque */
 135       /* alpha channel value */
 136 #ifdef RGB_ALPHA
 137       outptr[RGB_ALPHA] = 0xFF;
 138 #endif
 139       outptr += RGB_PIXELSIZE;
 140     }
 141   }
 142 }