1 /*
2  * Copyright (c) 2015 Kevin Wheatley <kevin.j.wheatley@gmail.com>
3  *
4  * This file is part of FFmpeg.
5  *
6  * FFmpeg is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU Lesser General Public
8  * License as published by the Free Software Foundation; either
9  * version 2.1 of the License, or (at your option) any later version.
10  *
11  * FFmpeg is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
14  * Lesser General Public License for more details.
15  *
16  * You should have received a copy of the GNU Lesser General Public
17  * License along with FFmpeg; if not, write to the Free Software
18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19  */
20 
21 #ifndef AVUTIL_COLOR_UTILS_H
22 #define AVUTIL_COLOR_UTILS_H
23 
24 
25 #include "libavutil/pixfmt.h"
26 
27 /**
28  * Determine a suitable 'gamma' value to match the supplied
29  * AVColorTransferCharacteristic.
30  *
31  * See Apple Technical Note TN2257 (https://developer.apple.com/library/mac/technotes/tn2257/_index.html)
32  *
33  * @return Will return an approximation to the simple gamma function matching
34  *         the supplied Transfer Characteristic, Will return 0.0 for any
35  *         we cannot reasonably match against.
36  */
37 double avpriv_get_gamma_from_trc(enum AVColorTransferCharacteristic trc);
38 
39 
40 typedef double (*avpriv_trc_function)(double);
41 
42 /**
43  * Determine the function needed to apply the given
44  * AVColorTransferCharacteristic to linear input.
45  *
46  * The function returned should expect a nominal domain and range of [0.0-1.0]
47  * values outside of this range maybe valid depending on the chosen
48  * characteristic function.
49  *
50  * @return Will return pointer to the function matching the
51  *         supplied Transfer Characteristic. If unspecified will
52  *         return NULL:
53  */
54 avpriv_trc_function avpriv_get_trc_function_from_trc(enum AVColorTransferCharacteristic trc);
55 
56 #endif
57