3 files changed, 49 insertions, 0 deletions
diff --git a/tests/sdl_canvas_alpha.c b/tests/sdl_canvas_alpha.c
new file mode 100644
index 00000000..1a41d115
--- /dev/null
+++ b/tests/sdl_canvas_alpha.c
@@ -0,0 +1,46 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <SDL/SDL.h>
+#include <SDL/SDL_ttf.h>
+#include <emscripten.h>
+
+
+int main(int argc, char **argv) {
+  SDL_Init(SDL_INIT_VIDEO);
+  SDL_Surface *screen = SDL_SetVideoMode(600, 450, 32, SDL_HWSURFACE);
+
+  printf("Init: %d\n", TTF_Init());
+
+  TTF_Font *font = TTF_OpenFont("sans-serif", 40);
+  printf("Font: %p\n", font);
+
+  SDL_Color color = { 0xff, 0x99, 0x00, 0xff };
+  SDL_Surface *text = TTF_RenderText_Solid(font, "hello orange world", color);
+
+  // render
+  for (int i = 0; i < 255; i++) {
+    SDL_Rect dest = { i, i, 0, 0 };
+    SDL_SetAlpha(text, 0, (((float)i)/255)*(((float)i)/255)*255);
+    SDL_BlitSurface (text, NULL, screen, &dest);
+  }
+
+  SDL_Flip(screen); 
+
+  SDL_LockSurface(screen);
+
+  int width, height, isFullscreen;
+  emscripten_get_canvas_size(&width, &height, &isFullscreen);
+
+  if (width != 600 && height != 450)
+  {
+    printf("error: wrong width/height\n");
+    abort();
+  }
+
+  SDL_Quit();
+
+  printf("done.\n");
+
+  return 0;
+}
+
diff --git a/tests/sdl_canvas_alpha.png b/tests/sdl_canvas_alpha.png
new file mode 100644
index 00000000..fb9d6165
--- /dev/null
+++ b/tests/sdl_canvas_alpha.png
diff --git a/tests/test_browser.py b/tests/test_browser.py
index e8cd57e5..8d000cd7 100644
--- a/tests/test_browser.py
+++ b/tests/test_browser.py
@@ -650,6 +650,9 @@ window.close = function() {
 
     self.btest('sdl_canvas_proxy.c', reference='sdl_canvas_proxy.png', args=['--proxy-to-worker', '--preload-file', 'data.txt'], manual_reference=True, post_build=post)
 
+  def test_sdl_canvas_alpha(self):
+    self.btest('sdl_canvas_alpha.c', reference='sdl_canvas_alpha.png')
+
   def test_sdl_key(self):
     open(os.path.join(self.get_dir(), 'pre.js'), 'w').write('''
       Module.postRun = function() {