Change thumbnail creation from nearest neighbor to linear interpolation, set body thumbnail size for 4chan and matrix (if available)

1 files changed, 24 insertions, 4 deletions

diff --git a/src/AsyncImageLoader.cpp b/src/AsyncImageLoader.cpp
index 8f771e7..00ca7ee 100644
--- a/src/AsyncImageLoader.cpp
+++ b/src/AsyncImageLoader.cpp
@@ -19,6 +19,7 @@ namespace QuickMedia {
         return sf::Vector2u(vec.x, vec.y);
     }
 
+    // Linear interpolation
     static void copy_resize(const sf::Image &source, sf::Image &destination, sf::Vector2u destination_size) {
         const sf::Vector2u source_size = source.getSize();
         if(source_size.x == 0 || source_size.y == 0 || destination_size.x == 0 || destination_size.y == 0)
@@ -33,14 +34,33 @@ namespace QuickMedia {
         sf::Uint32 *destination_pixel = destination_pixels;
         for(unsigned int y = 0; y < destination_size.y; ++y) {
             for(unsigned int x = 0; x < destination_size.x; ++x) {
-                int scaled_x = ((float)x / (float)destination_size.x) * source_size.x;
-                int scaled_y = ((float)y / (float)destination_size.y) * source_size.y;
+                int scaled_x_start = ((float)x / (float)destination_size.x) * source_size.x;
+                int scaled_y_start = ((float)y / (float)destination_size.y) * source_size.y;
+                int scaled_x_end = ((float)(x + 1) / (float)destination_size.x) * source_size.x;
+                int scaled_y_end = ((float)(y + 1) / (float)destination_size.y) * source_size.y;
                 //float scaled_x = x * width_ratio;
                 //float scaled_y = y * height_ratio;
 
                 //sf::Uint32 *source_pixel = (sf::Uint32*)(source_pixels + (int)(scaled_x + scaled_y * source_size.x) * 4);
-                sf::Uint32 *source_pixel = (sf::Uint32*)(source_pixels + (scaled_x + scaled_y * source_size.x) * 4);
-                *destination_pixel = *source_pixel;
+                sf::Uint32 sum_red = 0;
+                sf::Uint32 sum_green = 0;
+                sf::Uint32 sum_blue = 0;
+                sf::Uint32 sum_alpha = 0;
+                sf::Uint32 num_colors = (scaled_x_end - scaled_x_start) * (scaled_y_end - scaled_y_start);
+                for(int yy = scaled_y_start; yy < scaled_y_end; ++yy) {
+                    for(int xx = scaled_x_start; xx < scaled_x_end; ++xx) {
+                        sf::Uint32 *source_pixel = (sf::Uint32*)(source_pixels + (xx + yy * source_size.x) * 4);
+                        sum_red += (*source_pixel >> 24);
+                        sum_green += ((*source_pixel >> 16) & 0xFF);
+                        sum_blue += ((*source_pixel >> 8) & 0xFF);
+                        sum_alpha += (*source_pixel & 0xFF);
+                    }
+                }
+                sum_red /= num_colors;
+                sum_green /= num_colors;
+                sum_blue /= num_colors;
+                sum_alpha /= num_colors;
+                *destination_pixel = (sum_red << 24) | (sum_green << 16) | (sum_blue << 8) | sum_alpha;
                 ++destination_pixel;
             }
         }