1 files changed, 43 insertions, 0 deletions
diff --git a/tools/addon-sdk-1.5/packages/api-utils/lib/utils/thumbnail.js b/tools/addon-sdk-1.5/packages/api-utils/lib/utils/thumbnail.js
new file mode 100644
index 0000000..dfd03dd
--- /dev/null
+++ b/tools/addon-sdk-1.5/packages/api-utils/lib/utils/thumbnail.js
@@ -0,0 +1,43 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+"use strict";
+
+const { Cc, Ci, Cu } = require("chrome");
+const AppShellService = Cc["@mozilla.org/appshell/appShellService;1"].
+  getService(Ci.nsIAppShellService);
+
+const NS = "http://www.w3.org/1999/xhtml";
+const COLOR = "rgb(255,255,255)";
+
+/**
+ * Creates canvas element with a thumbnail of the passed window.
+ * @param {Window} window
+ * @returns {Element}
+ */
+function getThumbnailCanvasForWindow(window) {
+  let aspectRatio = 0.5625; // 16:9
+  let thumbnail = AppShellService.hiddenDOMWindow.document
+                    .createElementNS(NS, "canvas");
+  thumbnail.mozOpaque = true;
+  thumbnail.width = Math.ceil(window.screen.availWidth / 5.75);
+  thumbnail.height = Math.round(thumbnail.width * aspectRatio);
+  let ctx = thumbnail.getContext("2d");
+  let snippetWidth = window.innerWidth * .6;
+  let scale = thumbnail.width / snippetWidth;
+  ctx.scale(scale, scale);
+  ctx.drawWindow(window, window.scrollX, window.scrollY, snippetWidth,
+                snippetWidth * aspectRatio, COLOR);
+  return thumbnail;
+}
+exports.getThumbnailCanvasForWindow = getThumbnailCanvasForWindow;
+
+/**
+ * Creates Base64 encoded data URI of the thumbnail for the passed window.
+ * @param {Window} window
+ * @returns {String}
+ */
+exports.getThumbnailURIForWindow = function getThumbnailURIForWindow(window) {
+  return getThumbnailCanvasForWindow(window).toDataURL()
+};