/*
  * 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];
 }