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, 2015, D. R. Commander.
8 * For conditions of distribution and use, see the accompanying README.ijg
9 * file.
10 *
11 * This file contains output colorspace conversion routines.
12 */
13
14
15/* This file is included by jdcolor.c */
16
17
18/*
19 * Convert some rows of samples to the output colorspace.
20 *
21 * Note that we change from noninterleaved, one-plane-per-component format
22 * to interleaved-pixel format.  The output buffer is therefore three times
23 * as wide as the input buffer.
24 * A starting row offset is provided only for the input buffer.  The caller
25 * can easily adjust the passed output_buf value to accommodate any row
26 * offset required on that side.
27 */
28
29INLINE
30LOCAL(void)
31ycc_rgb_convert_internal (j_decompress_ptr cinfo,
32                          JSAMPIMAGE input_buf, JDIMENSION input_row,
33                          JSAMPARRAY output_buf, int num_rows)
34{
35  my_cconvert_ptr cconvert = (my_cconvert_ptr) cinfo->cconvert;
36  register int y, cb, cr;
37  register JSAMPROW outptr;
38  register JSAMPROW inptr0, inptr1, inptr2;
39  register JDIMENSION col;
40  JDIMENSION num_cols = cinfo->output_width;
41  /* copy these pointers into registers if possible */
42  register JSAMPLE * range_limit = cinfo->sample_range_limit;
43  register int * Crrtab = cconvert->Cr_r_tab;
44  register int * Cbbtab = cconvert->Cb_b_tab;
45  register JLONG * Crgtab = cconvert->Cr_g_tab;
46  register JLONG * Cbgtab = cconvert->Cb_g_tab;
47  SHIFT_TEMPS
48
49  while (--num_rows >= 0) {
50    inptr0 = input_buf[0][input_row];
51    inptr1 = input_buf[1][input_row];
52    inptr2 = input_buf[2][input_row];
53    input_row++;
54    outptr = *output_buf++;
55    for (col = 0; col < num_cols; col++) {
56      y  = GETJSAMPLE(inptr0[col]);
57      cb = GETJSAMPLE(inptr1[col]);
58      cr = GETJSAMPLE(inptr2[col]);
59      /* Range-limiting is essential due to noise introduced by DCT losses. */
60      outptr[RGB_RED] =   range_limit[y + Crrtab[cr]];
61      outptr[RGB_GREEN] = range_limit[y +
62                              ((int) RIGHT_SHIFT(Cbgtab[cb] + Crgtab[cr],
63                                                 SCALEBITS))];
64      outptr[RGB_BLUE] =  range_limit[y + Cbbtab[cb]];
65      /* Set unused byte to 0xFF so it can be interpreted as an opaque */
66      /* alpha channel value */
67#ifdef RGB_ALPHA
68      outptr[RGB_ALPHA] = 0xFF;
69#endif
70      outptr += RGB_PIXELSIZE;
71    }
72  }
73}
74
75
76/*
77 * Convert grayscale to RGB: just duplicate the graylevel three times.
78 * This is provided to support applications that don't want to cope
79 * with grayscale as a separate case.
80 */
81
82INLINE
83LOCAL(void)
84gray_rgb_convert_internal (j_decompress_ptr cinfo,
85                           JSAMPIMAGE input_buf, JDIMENSION input_row,
86                           JSAMPARRAY output_buf, int num_rows)
87{
88  register JSAMPROW inptr, outptr;
89  register JDIMENSION col;
90  JDIMENSION num_cols = cinfo->output_width;
91
92  while (--num_rows >= 0) {
93    inptr = input_buf[0][input_row++];
94    outptr = *output_buf++;
95    for (col = 0; col < num_cols; col++) {
96      /* We can dispense with GETJSAMPLE() here */
97      outptr[RGB_RED] = outptr[RGB_GREEN] = outptr[RGB_BLUE] = inptr[col];
98      /* Set unused byte to 0xFF so it can be interpreted as an opaque */
99      /* alpha channel value */
100#ifdef RGB_ALPHA
101      outptr[RGB_ALPHA] = 0xFF;
102#endif
103      outptr += RGB_PIXELSIZE;
104    }
105  }
106}
107
108
109/*
110 * Convert RGB to extended RGB: just swap the order of source pixels
111 */
112
113INLINE
114LOCAL(void)
115rgb_rgb_convert_internal (j_decompress_ptr cinfo,
116                          JSAMPIMAGE input_buf, JDIMENSION input_row,
117                          JSAMPARRAY output_buf, int num_rows)
118{
119  register JSAMPROW inptr0, inptr1, inptr2;
120  register JSAMPROW outptr;
121  register JDIMENSION col;
122  JDIMENSION num_cols = cinfo->output_width;
123
124  while (--num_rows >= 0) {
125    inptr0 = input_buf[0][input_row];
126    inptr1 = input_buf[1][input_row];
127    inptr2 = input_buf[2][input_row];
128    input_row++;
129    outptr = *output_buf++;
130    for (col = 0; col < num_cols; col++) {
131      /* We can dispense with GETJSAMPLE() here */
132      outptr[RGB_RED] = inptr0[col];
133      outptr[RGB_GREEN] = inptr1[col];
134      outptr[RGB_BLUE] = inptr2[col];
135      /* Set unused byte to 0xFF so it can be interpreted as an opaque */
136      /* alpha channel value */
137#ifdef RGB_ALPHA
138      outptr[RGB_ALPHA] = 0xFF;
139#endif
140      outptr += RGB_PIXELSIZE;
141    }
142  }
143}
144