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e4fe535d12
This will allow to copy the matrix as is and it is just cleaner to keep the matrix in the same order specified by the mov standard (which is also explicitly described in the documentation). In order to preserve compatibility, flip the angle sign in the display API av_display_rotation_set() and av_display_rotation_get(), and improve the documentation mentioning the rotation direction.
76 lines
2.2 KiB
C
76 lines
2.2 KiB
C
/*
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* Copyright (c) 2014 Vittorio Giovara <vittorio.giovara@gmail.com>
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*
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* This file is part of Libav.
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*
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* Libav is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* Libav is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with Libav; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include <stdint.h>
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#include <string.h>
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#include <math.h>
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#include "display.h"
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#include "mathematics.h"
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// fixed point to double
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#define CONV_FP(x) ((double) (x)) / (1 << 16)
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// double to fixed point
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#define CONV_DB(x) (int32_t) ((x) * (1 << 16))
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double av_display_rotation_get(const int32_t matrix[9])
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{
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double rotation, scale[2];
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scale[0] = sqrt(CONV_FP(matrix[0]) * CONV_FP(matrix[0]) +
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CONV_FP(matrix[3]) * CONV_FP(matrix[3]));
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scale[1] = sqrt(CONV_FP(matrix[1]) * CONV_FP(matrix[1]) +
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CONV_FP(matrix[4]) * CONV_FP(matrix[4]));
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if (scale[0] == 0.0 || scale[1] == 0.0)
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return NAN;
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rotation = atan2(CONV_FP(matrix[1]) / scale[1],
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CONV_FP(matrix[0]) / scale[0]) * 180 / M_PI;
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return -rotation;
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}
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void av_display_rotation_set(int32_t matrix[9], double angle)
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{
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double radians = -angle * M_PI / 180.0f;
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double c = cos(radians);
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double s = sin(radians);
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memset(matrix, 0, 9 * sizeof(int32_t));
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matrix[0] = CONV_DB(c);
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matrix[1] = CONV_DB(-s);
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matrix[3] = CONV_DB(s);
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matrix[4] = CONV_DB(c);
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matrix[8] = 1 << 30;
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}
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void av_display_matrix_flip(int32_t matrix[9], int hflip, int vflip)
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{
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int i;
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const int flip[] = { 1 - 2 * (!!hflip), 1 - 2 * (!!vflip), 1 };
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if (hflip || vflip)
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for (i = 0; i < 9; i++)
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matrix[i] *= flip[i % 3];
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}
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