2 files changed, 56 insertions, 0 deletions
diff --git a/src/jsifier.js b/src/jsifier.js
index 3d8059b1..a3b26aa9 100644
--- a/src/jsifier.js
+++ b/src/jsifier.js
@@ -1843,6 +1843,9 @@ function JSify(data, functionsOnly, givenFunctions) {
       print(read('headless.js').replace("'%s'", "'http://emscripten.org'").replace("'?%s'", "''").replace("'?%s'", "'/'").replace('%s,', 'null,').replace('%d', '0'));
       print('}');
     }
+    if (PROXY_TO_WORKER) {
+      print(read('proxyWorker.js'));
+    }
     if (RUNTIME_TYPE_INFO) {
       Types.cleanForRuntime();
       print('Runtime.typeInfo = ' + JSON.stringify(Types.types));
diff --git a/src/proxyWorker.js b/src/proxyWorker.js
new file mode 100644
index 00000000..2798b3d0
--- /dev/null
+++ b/src/proxyWorker.js
@@ -0,0 +1,53 @@
+
+function EventListener() {
+  this.listeners = {};
+
+  this.addEventListener = function(event, func) {
+    if (!this.listeners[event]) this.listeners[event] = [];
+    this.listeners[event].push(func);
+  };
+};
+
+var window = new EventListener();
+var document = new EventListener();
+
+document.createElement = function(what) {
+  switch(what) {
+    case 'canvas': {
+      var canvas = new EventListener();
+      canvas.ensureData = function() {
+        if (!canvas.data || canvas.data.width !== canvas.width || canvas.data.height !== canvas.height) {
+          canvas.data = {
+            width: canvas.width,
+            height: canvas.height,
+            buffer: new Uint8Array(canvas.width*canvas.height*4)
+          };
+        }
+      };
+      canvas.getContext = function(type) {
+        assert(type == '2d');
+        return {
+          getImageData: function(x, y, w, h) {
+            assert(x == 0 && y == 0 && w == canvas.width && h == canvas.height);
+            canvas.ensureData();
+            return {
+              width: canvas.data.width,
+              height: canvas.data.height,
+              data: new Uint8Array(canvas.data.buffer) // TODO: can we avoid this copy?
+            };
+          },
+          putImageData: function(image, x, y) {
+            canvas.ensureData();
+            assert(x == 0 && y == 0 && image.width == canvas.width && image.height == canvas.height);
+            canvas.data.buffer.set(image.data); // TODO: can we avoid this copy?
+          }
+        };
+      };
+      return canvas;
+    }
+    default: throw 'document.createElement ' + what;
+  }
+};
+
+Module.canvas = document.createElement('canvas');
+