1 void bilinera_interpolation(short** in_array, short height, short width, 
 2                             short** out_array, short out_height, short out_width)
 3 {
 4     double h_times = (double)out_height / (double)height,
 5            w_times = (double)out_width / (double)width;
 6     short  x1, y1, x2, y2, f11, f12, f21, f22;
 
 7     double x, y;
 8 
 9     for (int i = 0; i < out_height; i++){
10         for (int j = 0; j < out_width; j++){
11             x = j / w_times;
12             y = i / h_times;
13             x1 = (short)(x - 1);
14             x2 = (short)(x + 1);
15             y1 = (short)(y + 1);
16             y2 = (short
 
)(y - 1);
17             f11 = is_in_array(x1, y1, height, width) ? in_array[y1][x1] : 0;
18             f12 = is_in_array(x1, y2, height, width) ? in_array[y2][x1] : 0;
19             f21 = is_in_array(x2, y1, height, width) ? in_array[y1][x2] : 0;
20             f22 = is_in_array(x2, y2, height, width) ? in_array[y2][x2] : 0
 
;
21             out_array[i][j] = (short)(((f11 * (x2 - x) * (y2 - y)) +
22                                        (f21 * (x - x1) * (y2 - y)) +
23                                        (f12 * (x2 - x) * (y - y1)) +
24                                        (f22 * (x - x1) * (y - y1))) / ((x2 - x1) * (y2 - y1)));
25         }
26     }
27 }