/*

 * 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;

}

void av_display_matrix_flip(int32_t matrix[9], int hflip, int vflip)

{

    int i;

    const int flip[] = { 1 - 2 * (!!hflip), 1 - 2 * (!!vflip), 1 };

    if (hflip || vflip)

        for (i = 0; i < 9; i++)

            matrix[i] *= flip[i % 3];

}