4 * This file was part of the Independent JPEG Group's software:
5 * Copyright (C) 1991-1996, Thomas G. Lane.
7 * Copyright (C) 2009-2012, D. R. Commander.
8 * For conditions of distribution and use, see the accompanying README file.
10 * This file contains input colorspace conversion routines.
14 /* This file is included by jccolor.c */
18 * Convert some rows of samples to the JPEG colorspace.
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.
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.
31 rgb_ycc_convert_internal (j_compress_ptr cinfo
,
32 JSAMPARRAY input_buf
, JSAMPIMAGE output_buf
,
33 JDIMENSION output_row
, int num_rows
)
35 my_cconvert_ptr cconvert
= (my_cconvert_ptr
) cinfo
->cconvert
;
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
;
43 while (--num_rows
>= 0) {
45 outptr0
= output_buf
[0][output_row
];
46 outptr1
= output_buf
[1][output_row
];
47 outptr2
= output_buf
[2][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.
60 outptr0
[col
] = (JSAMPLE
)
61 ((ctab
[r
+R_Y_OFF
] + ctab
[g
+G_Y_OFF
] + ctab
[b
+B_Y_OFF
])
64 outptr1
[col
] = (JSAMPLE
)
65 ((ctab
[r
+R_CB_OFF
] + ctab
[g
+G_CB_OFF
] + ctab
[b
+B_CB_OFF
])
68 outptr2
[col
] = (JSAMPLE
)
69 ((ctab
[r
+R_CR_OFF
] + ctab
[g
+G_CR_OFF
] + ctab
[b
+B_CR_OFF
])
76 /**************** Cases other than RGB -> YCbCr **************/
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).
88 rgb_gray_convert_internal (j_compress_ptr cinfo
,
89 JSAMPARRAY input_buf
, JSAMPIMAGE output_buf
,
90 JDIMENSION output_row
, int num_rows
)
92 my_cconvert_ptr cconvert
= (my_cconvert_ptr
) cinfo
->cconvert
;
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
;
100 while (--num_rows
>= 0) {
101 inptr
= *input_buf
++;
102 outptr
= output_buf
[0][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
;
110 outptr
[col
] = (JSAMPLE
)
111 ((ctab
[r
+R_Y_OFF
] + ctab
[g
+G_Y_OFF
] + ctab
[b
+B_Y_OFF
])
119 * Convert some rows of samples to the JPEG colorspace.
120 * This version handles extended RGB->plain RGB conversion
125 rgb_rgb_convert_internal (j_compress_ptr cinfo
,
126 JSAMPARRAY input_buf
, JSAMPIMAGE output_buf
,
127 JDIMENSION output_row
, int num_rows
)
129 register JSAMPROW inptr
;
130 register JSAMPROW outptr0
, outptr1
, outptr2
;
131 register JDIMENSION col
;
132 JDIMENSION num_cols
= cinfo
->image_width
;
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
];
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
;