3 files changed, 63 insertions, 0 deletions

diff --git a/src/library_browser.js b/src/library_browser.js
index 4ef7c577..57ca5a24 100644
--- a/src/library_browser.js
+++ b/src/library_browser.js
@@ -1175,6 +1175,39 @@ mergeInto(LibraryManager.library, {
     var info = Browser.workers[id];
     if (!info) return -1;
     return info.awaited;
+  },
+
+  emscripten_get_preloaded_image_data: function(path, w, h) {
+    if (typeof path === "number") {
+      path = Pointer_stringify(path);
+    }
+
+    path = PATH.resolve(path);
+
+    var canvas = Module["preloadedImages"][path];
+    if (canvas) {
+      var ctx = canvas.getContext("2d");
+      var image = ctx.getImageData(0, 0, canvas.width, canvas.height);
+      var buf = _malloc(canvas.width * canvas.height * 4);
+
+      HEAPU8.set(image.data, buf);
+
+      {{{ makeSetValue('w', '0', 'canvas.width', 'i32') }}};
+      {{{ makeSetValue('h', '0', 'canvas.height', 'i32') }}};
+      return buf;
+    }
+
+    return 0;
+  },
+
+  emscripten_get_preloaded_image_data_from_FILE__deps: ['emscripten_get_preloaded_image_data'],
+  emscripten_get_preloaded_image_data_from_FILE: function(file, w, h) {
+    var stream = FS.getStreamFromPtr(file);
+    if (stream) {
+      return _emscripten_get_preloaded_image_data(stream.path, w, h);
+    }
+
+    return 0;
   }
 });
 
diff --git a/system/include/emscripten/emscripten.h b/system/include/emscripten/emscripten.h
index 6e1c00d5..b495c0f5 100644
--- a/system/include/emscripten/emscripten.h
+++ b/system/include/emscripten/emscripten.h
@@ -14,6 +14,8 @@
 extern "C" {
 #endif
 
+#include <stdio.h>
+
 #if !__EMSCRIPTEN__
 #include <SDL/SDL.h> /* for SDL_Delay in async_call */
 #endif
@@ -515,6 +517,24 @@ int emscripten_get_compiler_setting(const char *name);
  */
 void emscripten_debugger();
 
+/*
+ * Get preloaded image data and the size of the image.
+ *
+ * Returns pointer to loaded image or NULL.
+ * width/height of image are written to w/h if data is valid.
+ * Pointer should be free()'d
+ */
+char *emscripten_get_preloaded_image_data(const char *path, int *w, int *h);
+
+/*
+ * Get preloaded image data from a c FILE *.
+ *
+ * Returns pointer to loaded image or NULL.
+ * width/height of image are written to w/h if data is valid.
+ * Pointer should be free()'d
+ */
+char *emscripten_get_preloaded_image_data_from_FILE(FILE *file, int *w, int *h);
+
 
 /* ===================================== */
 /* Internal APIs. Be careful with these. */
diff --git a/tests/sdl_image.c b/tests/sdl_image.c
index 523f8903..9639ea37 100644
--- a/tests/sdl_image.c
+++ b/tests/sdl_image.c
@@ -4,6 +4,7 @@
 #include <assert.h>
 #include <emscripten.h>
 #include <unistd.h>
+#include <stdlib.h>
 
 int testImage(SDL_Surface* screen, const char* fileName) {
   SDL_Surface *image = IMG_Load(fileName);
@@ -18,7 +19,16 @@ int testImage(SDL_Surface* screen, const char* fileName) {
   int result = image->w;
 
   SDL_BlitSurface (image, NULL, screen, NULL);
+
+  int w, h;
+  char *data = emscripten_get_preloaded_image_data(fileName, &w, &h);
+
+  assert(data);
+  assert(w == image->w);
+  assert(h == image->h);
+
   SDL_FreeSurface (image);
+  free(data);
 
   return result;
 }