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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()
};
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