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, 2015, D. R. Commander.
8 * For conditions of distribution and use, see the accompanying README.ijg
9 * file.
10 *
11 * This file contains input colorspace conversion routines.
12 */
13
14
15/* This file is included by jccolor.c */
16
17
18/*
19 * Convert some rows of samples to the JPEG colorspace.
20 *
21 * Note that we change from the application's interleaved-pixel format
22 * to our internal noninterleaved, one-plane-per-component format.
23 * The input buffer is therefore three times as wide as the output buffer.
24 *
25 * A starting row offset is provided only for the output buffer. The caller
26 * can easily adjust the passed input_buf value to accommodate any row
27 * offset required on that side.
28 */
29
30INLINE
31LOCAL(void)
32rgb_ycc_convert_internal(j_compress_ptr cinfo, JSAMPARRAY input_buf,
33 JSAMPIMAGE output_buf, JDIMENSION output_row,
34 int num_rows)
35{
36 my_cconvert_ptr cconvert = (my_cconvert_ptr)cinfo->cconvert;
37 register int r, g, b;
38 register JLONG *ctab = cconvert->rgb_ycc_tab;
39 register JSAMPROW inptr;
40 register JSAMPROW outptr0, outptr1, outptr2;
41 register JDIMENSION col;
42 JDIMENSION num_cols = cinfo->image_width;
43
44 while (--num_rows >= 0) {
45 inptr = *input_buf++;
46 outptr0 = output_buf[0][output_row];
47 outptr1 = output_buf[1][output_row];
48 outptr2 = output_buf[2][output_row];
49 output_row++;
50 for (col = 0; col < num_cols; col++) {
51 r = GETJSAMPLE(inptr[RGB_RED]);
52 g = GETJSAMPLE(inptr[RGB_GREEN]);
53 b = GETJSAMPLE(inptr[RGB_BLUE]);
54 inptr += RGB_PIXELSIZE;
55 /* If the inputs are 0..MAXJSAMPLE, the outputs of these equations
56 * must be too; we do not need an explicit range-limiting operation.
57 * Hence the value being shifted is never negative, and we don't
58 * need the general RIGHT_SHIFT macro.
59 */
60 /* Y */
61 outptr0[col] = (JSAMPLE)((ctab[r + R_Y_OFF] + ctab[g + G_Y_OFF] +
62 ctab[b + B_Y_OFF]) >> SCALEBITS);
63 /* Cb */
64 outptr1[col] = (JSAMPLE)((ctab[r + R_CB_OFF] + ctab[g + G_CB_OFF] +
65 ctab[b + B_CB_OFF]) >> SCALEBITS);
66 /* Cr */
67 outptr2[col] = (JSAMPLE)((ctab[r + R_CR_OFF] + ctab[g + G_CR_OFF] +
68 ctab[b + B_CR_OFF]) >> SCALEBITS);
69 }
70 }
71}
72
73
74/**************** Cases other than RGB -> YCbCr **************/
75
76
77/*
78 * Convert some rows of samples to the JPEG colorspace.
79 * This version handles RGB->grayscale conversion, which is the same
80 * as the RGB->Y portion of RGB->YCbCr.
81 * We assume rgb_ycc_start has been called (we only use the Y tables).
82 */
83
84INLINE
85LOCAL(void)
86rgb_gray_convert_internal(j_compress_ptr cinfo, JSAMPARRAY input_buf,
87 JSAMPIMAGE output_buf, JDIMENSION output_row,
88 int num_rows)
89{
90 my_cconvert_ptr cconvert = (my_cconvert_ptr)cinfo->cconvert;
91 register int r, g, b;
92 register JLONG *ctab = cconvert->rgb_ycc_tab;
93 register JSAMPROW inptr;
94 register JSAMPROW outptr;
95 register JDIMENSION col;
96 JDIMENSION num_cols = cinfo->image_width;
97
98 while (--num_rows >= 0) {
99 inptr = *input_buf++;
100 outptr = output_buf[0][output_row];
101 output_row++;
102 for (col = 0; col < num_cols; col++) {
103 r = GETJSAMPLE(inptr[RGB_RED]);
104 g = GETJSAMPLE(inptr[RGB_GREEN]);
105 b = GETJSAMPLE(inptr[RGB_BLUE]);
106 inptr += RGB_PIXELSIZE;
107 /* Y */
108 outptr[col] = (JSAMPLE)((ctab[r + R_Y_OFF] + ctab[g + G_Y_OFF] +
109 ctab[b + B_Y_OFF]) >> SCALEBITS);
110 }
111 }
112}
113
114
115/*
116 * Convert some rows of samples to the JPEG colorspace.
117 * This version handles extended RGB->plain RGB conversion
118 */
119
120INLINE
121LOCAL(void)
122rgb_rgb_convert_internal(j_compress_ptr cinfo, JSAMPARRAY input_buf,
123 JSAMPIMAGE output_buf, JDIMENSION output_row,
124 int num_rows)
125{
126 register JSAMPROW inptr;
127 register JSAMPROW outptr0, outptr1, outptr2;
128 register JDIMENSION col;
129 JDIMENSION num_cols = cinfo->image_width;
130
131 while (--num_rows >= 0) {
132 inptr = *input_buf++;
133 outptr0 = output_buf[0][output_row];
134 outptr1 = output_buf[1][output_row];
135 outptr2 = output_buf[2][output_row];
136 output_row++;
137 for (col = 0; col < num_cols; col++) {
138 outptr0[col] = GETJSAMPLE(inptr[RGB_RED]);
139 outptr1[col] = GETJSAMPLE(inptr[RGB_GREEN]);
140 outptr2[col] = GETJSAMPLE(inptr[RGB_BLUE]);
141 inptr += RGB_PIXELSIZE;
142 }
143 }
144}
145