From acb80e111bfdd64c50310c3b0cec2de3f36251cd Mon Sep 17 00:00:00 2001
From: Harry Jeffery <harry@exec64.co.uk>
Date: Mon, 9 Nov 2015 15:58:36 +0000
Subject: Resample overlarge images

---
 main.c | 51 ++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 50 insertions(+), 1 deletion(-)

diff --git a/main.c b/main.c
index 97fb135..9738b46 100644
--- a/main.c
+++ b/main.c
@@ -54,9 +54,10 @@ struct {
   FIBITMAP *frame;
   SDL_Texture *tex;
   int width, height;
+  int max_width, max_height;
   int cur_frame, next_frame, num_frames, playing;
   double frame_time;
-} g_img = {NULL,NULL,NULL,0,0,0,0,0,0,0};
+} g_img = {NULL,NULL,NULL,0,0,0,0,0,0,0,0,0};
 
 void toggle_fullscreen()
 {
@@ -173,6 +174,41 @@ void prev_path()
   g_path.dir = -1;
 }
 
+void resample_image()
+{
+  double max_aspect = (double)g_img.max_width/(double)g_img.max_height;
+  double img_aspect = (double)g_img.width/(double)g_img.height;
+  double scale;
+
+  if(max_aspect > img_aspect) {
+    //Image will become too tall before it becomes too wide
+    scale = (double)g_img.max_height/(double)g_img.height;
+  } else {
+    //Image will become too wide before it becomes too tall
+    scale = (double)g_img.max_width/(double)g_img.width;
+  }
+
+  int new_width = g_img.width * scale;
+  int new_height = g_img.height * scale;
+
+  fprintf(stderr,
+      "Warning: '%s' [%ix%i] is too large to fit into a SDL texture. "
+      "Resampling to %ix%i\n",
+      g_path.cur->path,
+      g_img.width, g_img.height,
+      new_width, new_height);
+
+  //perform scaling
+  g_img.width = new_width;
+  g_img.height = new_height;
+
+  FIBITMAP *resampled = FreeImage_Rescale(g_img.frame,
+      g_img.width, g_img.height, FILTER_CATMULLROM);
+
+  FreeImage_Unload(g_img.frame);
+  g_img.frame = resampled;
+}
+
 void render_image(FIBITMAP *image)
 {
   if(g_img.frame) {
@@ -182,6 +218,10 @@ void render_image(FIBITMAP *image)
   g_img.width = FreeImage_GetWidth(g_img.frame);
   g_img.height = FreeImage_GetHeight(g_img.frame);
 
+  if(g_img.width > g_img.max_width || g_img.height > g_img.max_height) {
+    resample_image();
+  }
+
   char* pixels = (char*)FreeImage_GetBits(g_img.frame);
 
   if(g_img.tex) {
@@ -191,6 +231,9 @@ void render_image(FIBITMAP *image)
         SDL_PIXELFORMAT_RGB888,
         SDL_TEXTUREACCESS_STATIC,
         g_img.width, g_img.height);
+  if(g_img.tex == NULL) {
+    fprintf(stderr, "SDL Error when creating texture: %s\n", SDL_GetError());
+  }
   SDL_Rect area = {0,0,g_img.width,g_img.height};
   SDL_UpdateTexture(g_img.tex, &area, pixels, 4 * g_img.width);
   g_view.redraw = 1;
@@ -412,6 +455,12 @@ int main(int argc, char** argv)
   //Use linear sampling for scaling
   SDL_SetHint(SDL_HINT_RENDER_SCALE_QUALITY, "1");
 
+  //We need to know how big our textures can be
+  SDL_RendererInfo ri;
+  SDL_GetRendererInfo(g_renderer, &ri);
+  g_img.max_width = ri.max_texture_width;
+  g_img.max_height = ri.max_texture_height;
+
   //Put us in fullscren by default if requested
   if(g_options.fullscreen) {
     toggle_fullscreen();
-- 
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