1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
|
/****************************************************************************
* graphics/color/nxglib_yuv2rgb.c
*
* Copyright (C) 2008 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <spudmonkey@racsa.co.cr>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the name NuttX nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <sys/types.h>
#include <debug.h>
#include <fixedmath.h>
#include <nuttx/nxglib.h>
/****************************************************************************
* Pre-Processor Definitions
****************************************************************************/
#define b16_P3441 0x0000581a /* 0.344147 */
#define b16_P7141 0x0000b6d2 /* 0.714142 */
#define b16_1P402 0x000166ea /* 1.402008 */
#define b16_1P772 0x0001c5a2 /* 1.722003 */
#define b16_128P0 0x00800000 /* 128.000000 */
/****************************************************************************
* Private Types
****************************************************************************/
/****************************************************************************
* Private Function Prototypes
****************************************************************************/
/****************************************************************************
* Private Data
****************************************************************************/
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: nxgl_yuv2rgb
*
* Description:
* Convert 8-bit RGB triplet to 8-bit YUV triplet
*
****************************************************************************/
void nxgl_yuv2rgb(ubyte y, ubyte u, ubyte v, ubyte *r, ubyte *g, ubyte *b)
{
b16_t vm128 = itob16(v) - b16_128P0;
b16_t um128 = itob16(u) - b16_128P0;
/* Per the JFIF specification:
*
* R = Y + 1.40200 * (V - 128.0)
* G = Y - 0.34414 * (U - 128.0) - 0.71414 * (V - 128.0)
* B = Y + 1.77200 * (U - 128.0)
*/
*r = (ubyte)b16toi(itob16(y) + b16muli(b16_1P402, vm128));
*g = (ubyte)b16toi(itob16(y) - b16muli(b16_P3441, um128) - b16muli(b16_P7141, vm128));
*b = (ubyte)b16toi(itob16(y) + b16muli(b16_1P772, um128));
}
|
