media/libjpeg/jccolext.c

   1 /*
   2  * jccolext.c
   3  *
   4  * This file was part of the Independent JPEG Group's software:
   5  * Copyright (C) 1991-1996, Thomas G. Lane.
   6  * libjpeg-turbo Modifications:
   7  * Copyright (C) 2009-2012, D. R. Commander.
   8  * For conditions of distribution and use, see the accompanying README file.
   9  *
  10  * This file contains input colorspace conversion routines.
  11  */
  12
  13
  14 /* This file is included by jccolor.c */
  15
  16
  17 /*
  18  * Convert some rows of samples to the JPEG colorspace.
  19  *
  20  * Note that we change from the application's interleaved-pixel format
  21  * to our internal noninterleaved, one-plane-per-component format.
  22  * The input buffer is therefore three times as wide as the output buffer.
  23  *
  24  * A starting row offset is provided only for the output buffer.  The caller
  25  * can easily adjust the passed input_buf value to accommodate any row
  26  * offset required on that side.
  27  */
  28
  29 INLINE
  30 LOCAL(void)
  31 rgb_ycc_convert_internal (j_compress_ptr cinfo,
  32                           JSAMPARRAY input_buf, JSAMPIMAGE output_buf,
  33                           JDIMENSION output_row, int num_rows)
  34 {
  35   my_cconvert_ptr cconvert = (my_cconvert_ptr) cinfo->cconvert;
  36   register int r, g, b;
  37   register INT32 * ctab = cconvert->rgb_ycc_tab;
  38   register JSAMPROW inptr;
  39   register JSAMPROW outptr0, outptr1, outptr2;
  40   register JDIMENSION col;
  41   JDIMENSION num_cols = cinfo->image_width;
  42
  43   while (--num_rows >= 0) {
  44     inptr = *input_buf++;
  45     outptr0 = output_buf[0][output_row];
  46     outptr1 = output_buf[1][output_row];
  47     outptr2 = output_buf[2][output_row];
  48     output_row++;
  49     for (col = 0; col < num_cols; col++) {
  50       r = GETJSAMPLE(inptr[RGB_RED]);
  51       g = GETJSAMPLE(inptr[RGB_GREEN]);
  52       b = GETJSAMPLE(inptr[RGB_BLUE]);
  53       inptr += RGB_PIXELSIZE;
  54       /* If the inputs are 0..MAXJSAMPLE, the outputs of these equations
  55        * must be too; we do not need an explicit range-limiting operation.
  56        * Hence the value being shifted is never negative, and we don't
  57        * need the general RIGHT_SHIFT macro.
  58        */
  59       /* Y */
  60       outptr0[col] = (JSAMPLE)
  61                 ((ctab[r+R_Y_OFF] + ctab[g+G_Y_OFF] + ctab[b+B_Y_OFF])
  62                  >> SCALEBITS);
  63       /* Cb */
  64       outptr1[col] = (JSAMPLE)
  65                 ((ctab[r+R_CB_OFF] + ctab[g+G_CB_OFF] + ctab[b+B_CB_OFF])
  66                  >> SCALEBITS);
  67       /* Cr */
  68       outptr2[col] = (JSAMPLE)
  69                 ((ctab[r+R_CR_OFF] + ctab[g+G_CR_OFF] + ctab[b+B_CR_OFF])
  70                  >> SCALEBITS);
  71     }
  72   }
  73 }
  74
  75
  76 /**************** Cases other than RGB -> YCbCr **************/
  77
  78
  79 /*
  80  * Convert some rows of samples to the JPEG colorspace.
  81  * This version handles RGB->grayscale conversion, which is the same
  82  * as the RGB->Y portion of RGB->YCbCr.
  83  * We assume rgb_ycc_start has been called (we only use the Y tables).
  84  */
  85
  86 INLINE
  87 LOCAL(void)
  88 rgb_gray_convert_internal (j_compress_ptr cinfo,
  89                            JSAMPARRAY input_buf, JSAMPIMAGE output_buf,
  90                            JDIMENSION output_row, int num_rows)
  91 {
  92   my_cconvert_ptr cconvert = (my_cconvert_ptr) cinfo->cconvert;
  93   register int r, g, b;
  94   register INT32 * ctab = cconvert->rgb_ycc_tab;
  95   register JSAMPROW inptr;
  96   register JSAMPROW outptr;
  97   register JDIMENSION col;
  98   JDIMENSION num_cols = cinfo->image_width;
  99
 100   while (--num_rows >= 0) {
 101     inptr = *input_buf++;
 102     outptr = output_buf[0][output_row];
 103     output_row++;
 104     for (col = 0; col < num_cols; col++) {
 105       r = GETJSAMPLE(inptr[RGB_RED]);
 106       g = GETJSAMPLE(inptr[RGB_GREEN]);
 107       b = GETJSAMPLE(inptr[RGB_BLUE]);
 108       inptr += RGB_PIXELSIZE;
 109       /* Y */
 110       outptr[col] = (JSAMPLE)
 111                 ((ctab[r+R_Y_OFF] + ctab[g+G_Y_OFF] + ctab[b+B_Y_OFF])
 112                  >> SCALEBITS);
 113     }
 114   }
 115 }
 116
 117
 118 /*
 119  * Convert some rows of samples to the JPEG colorspace.
 120  * This version handles extended RGB->plain RGB conversion
 121  */
 122
 123 INLINE
 124 LOCAL(void)
 125 rgb_rgb_convert_internal (j_compress_ptr cinfo,
 126                           JSAMPARRAY input_buf, JSAMPIMAGE output_buf,
 127                           JDIMENSION output_row, int num_rows)
 128 {
 129   register JSAMPROW inptr;
 130   register JSAMPROW outptr0, outptr1, outptr2;
 131   register JDIMENSION col;
 132   JDIMENSION num_cols = cinfo->image_width;
 133
 134   while (--num_rows >= 0) {
 135     inptr = *input_buf++;
 136     outptr0 = output_buf[0][output_row];
 137     outptr1 = output_buf[1][output_row];
 138     outptr2 = output_buf[2][output_row];
 139     output_row++;
 140     for (col = 0; col < num_cols; col++) {
 141       outptr0[col] = GETJSAMPLE(inptr[RGB_RED]);
 142       outptr1[col] = GETJSAMPLE(inptr[RGB_GREEN]);
 143       outptr2[col] = GETJSAMPLE(inptr[RGB_BLUE]);
 144       inptr += RGB_PIXELSIZE;
 145     }
 146   }
 147 }