2 * Copyright (c) 2014 Vittorio Giovara <vittorio.giovara@gmail.com>
4 * This file is part of FFmpeg.
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.
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.
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
26 #include "mathematics.h"
28 // fixed point to double
29 #define CONV_FP(x) ((double) (x)) / (1 << 16)
31 // double to fixed point
32 #define CONV_DB(x) (int32_t) ((x) * (1 << 16))
34 double av_display_rotation_get(const int32_t matrix
[9])
36 double rotation
, scale
[2];
38 scale
[0] = hypot(CONV_FP(matrix
[0]), CONV_FP(matrix
[3]));
39 scale
[1] = hypot(CONV_FP(matrix
[1]), CONV_FP(matrix
[4]));
41 if (scale
[0] == 0.0 || scale
[1] == 0.0)
44 rotation
= atan2(CONV_FP(matrix
[1]) / scale
[1],
45 CONV_FP(matrix
[0]) / scale
[0]) * 180 / M_PI
;
50 void av_display_rotation_set(int32_t matrix
[9], double angle
)
52 double radians
= angle
* M_PI
/ 180.0f
;
53 double c
= cos(radians
);
54 double s
= sin(radians
);
56 memset(matrix
, 0, 9 * sizeof(int32_t));
58 matrix
[0] = CONV_DB(c
);
59 matrix
[1] = CONV_DB(-s
);
60 matrix
[3] = CONV_DB(s
);
61 matrix
[4] = CONV_DB(c
);
65 void av_display_matrix_flip(int32_t matrix
[9], int hflip
, int vflip
)
68 const int flip
[] = { 1 - 2 * (!!hflip
), 1 - 2 * (!!vflip
), 1 };
71 for (i
= 0; i
< 9; i
++)
72 matrix
[i
] *= flip
[i
% 3];