/*
  * Copyright (C) 2010 Georg Martius <georg.martius@web.de>
  * Copyright (C) 2010 Daniel G. Taylor <dan@programmer-art.org>
  *
  * 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
  */
 
 /**

  * @file

  * transform input video
  */
 
 #include "libavutil/common.h"
 
 #include "transform.h"
 
 #define INTERPOLATE_METHOD(name) \
     static uint8_t name(float x, float y, const uint8_t *src, \
                         int width, int height, int stride, uint8_t def)
 
 #define PIXEL(img, x, y, w, h, stride, def) \
     ((x) < 0 || (y) < 0) ? (def) : \
     (((x) >= (w) || (y) >= (h)) ? (def) : \
     img[(x) + (y) * (stride)])
 
 /**
  * Nearest neighbor interpolation
  */
 INTERPOLATE_METHOD(interpolate_nearest)
 {
     return PIXEL(src, (int)(x + 0.5), (int)(y + 0.5), width, height, stride, def);
 }
 
 /**
  * Bilinear interpolation
  */
 INTERPOLATE_METHOD(interpolate_bilinear)
 {
     int x_c, x_f, y_c, y_f;
     int v1, v2, v3, v4;
 
     if (x < -1 || x > width || y < -1 || y > height) {
         return def;
     } else {
         x_f = (int)x;
         x_c = x_f + 1;
 
         y_f = (int)y;
         y_c = y_f + 1;
 
         v1 = PIXEL(src, x_c, y_c, width, height, stride, def);
         v2 = PIXEL(src, x_c, y_f, width, height, stride, def);
         v3 = PIXEL(src, x_f, y_c, width, height, stride, def);
         v4 = PIXEL(src, x_f, y_f, width, height, stride, def);
 
         return (v1*(x - x_f)*(y - y_f) + v2*((x - x_f)*(y_c - y)) +
                 v3*(x_c - x)*(y - y_f) + v4*((x_c - x)*(y_c - y)));
     }
 }
 
 /**
  * Biquadratic interpolation
  */
 INTERPOLATE_METHOD(interpolate_biquadratic)
 {
     int     x_c, x_f, y_c, y_f;
     uint8_t v1,  v2,  v3,  v4;
     float   f1,  f2,  f3,  f4;
 
     if (x < - 1 || x > width || y < -1 || y > height)
         return def;
     else {
         x_f = (int)x;
         x_c = x_f + 1;
         y_f = (int)y;
         y_c = y_f + 1;
 
         v1 = PIXEL(src, x_c, y_c, width, height, stride, def);
         v2 = PIXEL(src, x_c, y_f, width, height, stride, def);
         v3 = PIXEL(src, x_f, y_c, width, height, stride, def);
         v4 = PIXEL(src, x_f, y_f, width, height, stride, def);
 
         f1 = 1 - sqrt((x_c - x) * (y_c - y));
         f2 = 1 - sqrt((x_c - x) * (y - y_f));
         f3 = 1 - sqrt((x - x_f) * (y_c - y));
         f4 = 1 - sqrt((x - x_f) * (y - y_f));
         return (v1 * f1 + v2 * f2 + v3 * f3 + v4 * f4) / (f1 + f2 + f3 + f4);
     }
 }
 
 void avfilter_get_matrix(float x_shift, float y_shift, float angle, float zoom, float *matrix) {
     matrix[0] = zoom * cos(angle);
     matrix[1] = -sin(angle);
     matrix[2] = x_shift;
     matrix[3] = -matrix[1];
     matrix[4] = matrix[0];
     matrix[5] = y_shift;
     matrix[6] = 0;
     matrix[7] = 0;
     matrix[8] = 1;
 }
 
 void avfilter_add_matrix(const float *m1, const float *m2, float *result)
 {

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

         result[i] = m1[i] + m2[i];
 }
 
 void avfilter_sub_matrix(const float *m1, const float *m2, float *result)
 {

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

         result[i] = m1[i] - m2[i];
 }
 
 void avfilter_mul_matrix(const float *m1, float scalar, float *result)
 {

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

         result[i] = m1[i] * scalar;
 }
 
 void avfilter_transform(const uint8_t *src, uint8_t *dst,
                         int src_stride, int dst_stride,
                         int width, int height, const float *matrix,
                         enum InterpolateMethod interpolate,
                         enum FillMethod fill)
 {
     int x, y;
     float x_s, y_s;
     uint8_t def = 0;
     uint8_t (*func)(float, float, const uint8_t *, int, int, int, uint8_t) = NULL;
 
     switch(interpolate) {
         case INTERPOLATE_NEAREST:
             func = interpolate_nearest;
             break;
         case INTERPOLATE_BILINEAR:
             func = interpolate_bilinear;
             break;
         case INTERPOLATE_BIQUADRATIC:
             func = interpolate_biquadratic;
             break;
     }
 
     for (y = 0; y < height; y++) {
         for(x = 0; x < width; x++) {
             x_s = x * matrix[0] + y * matrix[1] + matrix[2];
             y_s = x * matrix[3] + y * matrix[4] + matrix[5];
 
             switch(fill) {
                 case FILL_ORIGINAL:
                     def = src[y * src_stride + x];
                     break;
                 case FILL_CLAMP:
                     y_s = av_clipf(y_s, 0, height - 1);
                     x_s = av_clipf(x_s, 0, width - 1);
                     def = src[(int)y_s * src_stride + (int)x_s];
                     break;
                 case FILL_MIRROR:
                     y_s = (y_s < 0) ? -y_s : (y_s >= height) ? (height + height - y_s) : y_s;
                     x_s = (x_s < 0) ? -x_s : (x_s >= width) ? (width + width - x_s) : x_s;
                     def = src[(int)y_s * src_stride + (int)x_s];
             }
 
             dst[y * dst_stride + x] = func(x_s, y_s, src, width, height, src_stride, def);
         }
     }
 }