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
LOCAL(void)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
LOCAL(void)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
LOCAL(void)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 }
143