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
29INLINE
30LOCAL(void)
31rgb_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
86INLINE
87LOCAL(void)
88rgb_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
123INLINE
124LOCAL(void)
125rgb_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}
148