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
LOCAL(void)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
LOCAL(void)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
LOCAL(void)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 }
148