1 files changed, 69 insertions, 0 deletions
diff --git a/chrome/renderer/resources/extensions/image_util.js b/chrome/renderer/resources/extensions/image_util.js
new file mode 100644
index 0000000..4f418e2
--- /dev/null
+++ b/chrome/renderer/resources/extensions/image_util.js
@@ -0,0 +1,69 @@
+// Copyright 2013 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// This function takes an object |imageSpec| with the key |path| -
+// corresponding to the internet URL to be translated - and optionally
+// |width| and |height| which are the maximum dimensions to be used when
+// converting the image.
+function loadDataUrl(imageSpec, callbacks) {
+  var path = imageSpec.path;
+  var img = new Image();
+  if (typeof callbacks.onerror === 'function') {
+    img.onerror = function() {
+      callbacks.onerror({ problem: 'could_not_load', path: path });
+    };
+  }
+  img.onload = function() {
+    var canvas = document.createElement('canvas');
+
+    canvas.width = img.width;
+    if (imageSpec.width && imageSpec.width < img.width)
+      canvas.width = imageSpec.width;
+    canvas.height = img.height;
+    if (imageSpec.height && imageSpec.height < img.height)
+      canvas.height = imageSpec.height;
+
+    var canvas_context = canvas.getContext('2d');
+    canvas_context.clearRect(0, 0, canvas.width, canvas.height);
+    canvas_context.drawImage(img, 0, 0, canvas.width, canvas.height);
+    try {
+      var dataUrl = canvas.toDataURL();
+      if (typeof callbacks.oncomplete === 'function') {
+        callbacks.oncomplete(dataUrl);
+      }
+    } catch (e) {
+      if (typeof callbacks.onerror === 'function') {
+        callbacks.onerror({ problem: 'data_url_unavailable', path: path });
+      }
+    }
+  }
+  img.src = path;
+}
+
+function on_complete_index(index, err, loading, finished, callbacks) {
+  return function(imageData) {
+    delete loading[index];
+    finished[index] = imageData;
+    if (err)
+      callbacks.onerror(index);
+    if (Object.keys(loading).length == 0)
+      callbacks.oncomplete(finished);
+  }
+}
+
+function loadAllImages(imageSpecs, callbacks) {
+  var loading = {}, finished = [],
+      index, pathname;
+
+  for (var index = 0; index < imageSpecs.length; index++) {
+    loading[index] = imageSpecs[index];
+    loadDataUrl(imageSpecs[index], {
+      oncomplete: on_complete_index(index, false, loading, finished, callbacks),
+      onerror: on_complete_index(index, true, loading, finished, callbacks)
+    });
+  }
+}
+
+exports.loadDataUrl = loadDataUrl;
+exports.loadAllImages = loadAllImages;