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-rw-r--r--addon-sdk/source/lib/sdk/content/thumbnail.js51
1 files changed, 51 insertions, 0 deletions
diff --git a/addon-sdk/source/lib/sdk/content/thumbnail.js b/addon-sdk/source/lib/sdk/content/thumbnail.js
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+++ b/addon-sdk/source/lib/sdk/content/thumbnail.js
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+/* 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';
+
+module.metadata = {
+ 'stability': 'unstable'
+};
+
+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()
+};
+
+// default 80x45 blank when not available
+exports.BLANK = 'data:image/png;base64,' +
+ 'iVBORw0KGgoAAAANSUhEUgAAAFAAAAAtCAYAAAA5reyyAAAAJElEQVRoge3BAQ'+
+ 'EAAACCIP+vbkhAAQAAAAAAAAAAAAAAAADXBjhtAAGQ0AF/AAAAAElFTkSuQmCC';