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/*
* Copyright (c) 2014 Vittorio Giovara <vittorio.giovara@gmail.com>
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include <stdint.h>
#include <string.h>
#include <math.h>
#include "display.h"
#include "mathematics.h"
// fixed point to double
#define CONV_FP(x) ((double) (x)) / (1 << 16)
// double to fixed point
#define CONV_DB(x) (int32_t) ((x) * (1 << 16))
double av_display_rotation_get(const int32_t matrix[9])
{
double rotation, scale[2];
scale[0] = hypot(CONV_FP(matrix[0]), CONV_FP(matrix[3]));
scale[1] = hypot(CONV_FP(matrix[1]), CONV_FP(matrix[4]));
if (scale[0] == 0.0 || scale[1] == 0.0)
return NAN;
rotation = atan2(CONV_FP(matrix[1]) / scale[1],
CONV_FP(matrix[0]) / scale[0]) * 180 / M_PI;
return rotation;
}
void av_display_rotation_set(int32_t matrix[9], double angle)
{
double radians = angle * M_PI / 180.0f;
double c = cos(radians);
double s = sin(radians);
memset(matrix, 0, 9 * sizeof(int32_t));
matrix[0] = CONV_DB(c);
matrix[1] = CONV_DB(-s);
matrix[3] = CONV_DB(s);
matrix[4] = CONV_DB(c);
matrix[8] = 1 << 30;
}
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