forked from mirrors/gecko-dev
51 lines
1.8 KiB
JavaScript
51 lines
1.8 KiB
JavaScript
/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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'use strict';
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module.metadata = {
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'stability': 'unstable'
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};
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const { Cc, Ci, Cu } = require('chrome');
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const AppShellService = Cc['@mozilla.org/appshell/appShellService;1'].
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getService(Ci.nsIAppShellService);
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const NS = 'http://www.w3.org/1999/xhtml';
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const COLOR = 'rgb(255,255,255)';
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/**
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* Creates canvas element with a thumbnail of the passed window.
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* @param {Window} window
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* @returns {Element}
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*/
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function getThumbnailCanvasForWindow(window) {
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let aspectRatio = 0.5625; // 16:9
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let thumbnail = AppShellService.hiddenDOMWindow.document
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.createElementNS(NS, 'canvas');
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thumbnail.mozOpaque = true;
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thumbnail.width = Math.ceil(window.screen.availWidth / 5.75);
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thumbnail.height = Math.round(thumbnail.width * aspectRatio);
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let ctx = thumbnail.getContext('2d');
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let snippetWidth = window.innerWidth * .6;
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let scale = thumbnail.width / snippetWidth;
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ctx.scale(scale, scale);
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ctx.drawWindow(window, window.scrollX, window.scrollY, snippetWidth,
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snippetWidth * aspectRatio, COLOR);
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return thumbnail;
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}
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exports.getThumbnailCanvasForWindow = getThumbnailCanvasForWindow;
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/**
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* Creates Base64 encoded data URI of the thumbnail for the passed window.
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* @param {Window} window
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* @returns {String}
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*/
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exports.getThumbnailURIForWindow = function getThumbnailURIForWindow(window) {
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return getThumbnailCanvasForWindow(window).toDataURL()
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};
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// default 80x45 blank when not available
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exports.BLANK = 'data:image/png;base64,' +
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'iVBORw0KGgoAAAANSUhEUgAAAFAAAAAtCAYAAAA5reyyAAAAJElEQVRoge3BAQ'+
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'EAAACCIP+vbkhAAQAAAAAAAAAAAAAAAADXBjhtAAGQ0AF/AAAAAElFTkSuQmCC';
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