Fix image loading for cross-origin resources

src/imageloader.js

@@ -39,7 +39,7 @@ ImageLoader.prototype.loadImage = function(imageData) {
         } else if (this.support.cors && !this.options.allowTaint && this.options.useCORS) {
             return new ImageContainer(src, true);
         } else if (this.options.proxy) {
-            return new ProxyImageContainer(src);
+            return new ProxyImageContainer(src, this.options.proxy);
         } else {
             return new DummyImageContainer(src);
         }

src/proxyimagecontainer.js

@@ -0,0 +1,33 @@
+function ProxyImageContainer(src, proxy) {
+    var callbackName = "html2canvas_" + proxyImageCount++;
+    var script = document.createElement("script");
+    var link = document.createElement("a");
+    link.href = src;
+    src = link.href;
+    var requestUrl = proxy + ((proxy.indexOf("?") > -1) ? "&" : "?" ) + 'url=' + encodeURIComponent(src) + '&callback=' + callbackName;
+    this.src = src;
+    this.image = new Image();
+    var image = this.image;
+    this.promise = new Promise(function(resolve, reject) {
+        image.onload = resolve;
+        image.onerror = reject;
+
+        window[callbackName] = function(a){
+            if (a.substring(0,6) === "error:"){
+                reject();
+            } else {
+                image.src = a;
+            }
+            window[callbackName] = undefined; // to work with IE<9  // NOTE: that the undefined callback property-name still exists on the window object (for IE<9)
+            try {
+                delete window[callbackName];  // for all browser that support this
+            } catch(ex) {}
+            script.parentNode.removeChild(script);
+        };
+        script.setAttribute("type", "text/javascript");
+        script.setAttribute("src", requestUrl);
+        document.body.appendChild(script);
+    });
+}
+
+var proxyImageCount = 0;

tests/test.js

@@ -11,7 +11,7 @@ var h2cSelector, h2cOptions;
 
     document.write(srcStart + '/tests/assets/jquery-1.6.2.js' + scrEnd);
     document.write(srcStart + '/tests/assets/jquery.plugin.html2canvas.js' + scrEnd);
-    var html2canvas = ['log', 'nodecontainer', 'stackingcontext', 'textcontainer', 'support', 'imagecontainer', 'gradientcontainer', 'lineargradientcontainer', 'webkitgradientcontainer',
+    var html2canvas = ['log', 'nodecontainer', 'stackingcontext', 'textcontainer', 'support', 'imagecontainer', 'proxyimagecontainer', 'gradientcontainer', 'lineargradientcontainer', 'webkitgradientcontainer',
         'imageloader', 'nodeparser', 'font', 'fontmetrics', 'core', 'renderer', 'promise', 'renderers/canvas'], i;
     for (i = 0; i < html2canvas.length; ++i) {
         document.write(srcStart + '/src/' + html2canvas[i] + '.js?' + Math.random() + scrEnd);
@@ -30,7 +30,7 @@ var h2cSelector, h2cOptions;
                 logging: true,
                 profile: true,
                 proxy: "http://html2canvas.appspot.com/query",
-                useCORS: true
+                useCORS: false
             }, h2cOptions));
         }, 100);
     };