mirror of
https://github.com/classilla/tenfourfox.git
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91 lines
3.2 KiB
JavaScript
91 lines
3.2 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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const Ci = Components.interfaces;
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const Cc = Components.classes;
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const Cu = Components.utils;
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Cu.import("resource://gre/modules/XPCOMUtils.jsm");
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const XHTML_NS = "http://www.w3.org/1999/xhtml";
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const MAXIMUM_PIXELS = Math.pow(144, 2);
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function ColorAnalyzer() {
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// a queue of callbacks for each job we give to the worker
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this.callbacks = [];
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this.hiddenWindowDoc = Cc["@mozilla.org/appshell/appShellService;1"].
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getService(Ci.nsIAppShellService).
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hiddenDOMWindow.document;
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this.worker = new ChromeWorker("resource://gre/modules/ColorAnalyzer_worker.js");
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this.worker.onmessage = this.onWorkerMessage.bind(this);
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this.worker.onerror = this.onWorkerError.bind(this);
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}
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ColorAnalyzer.prototype = {
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findRepresentativeColor: function ColorAnalyzer_frc(imageURI, callback) {
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function cleanup() {
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image.removeEventListener("load", loadListener);
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image.removeEventListener("error", errorListener);
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}
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let image = this.hiddenWindowDoc.createElementNS(XHTML_NS, "img");
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let loadListener = this.onImageLoad.bind(this, image, callback, cleanup);
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let errorListener = this.onImageError.bind(this, image, callback, cleanup);
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image.addEventListener("load", loadListener);
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image.addEventListener("error", errorListener);
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image.src = imageURI.spec;
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},
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onImageLoad: function ColorAnalyzer_onImageLoad(image, callback, cleanup) {
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if (image.naturalWidth * image.naturalHeight > MAXIMUM_PIXELS) {
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// this will probably take too long to process - fail
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callback.onComplete(false);
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} else {
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let canvas = this.hiddenWindowDoc.createElementNS(XHTML_NS, "canvas");
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canvas.width = image.naturalWidth;
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canvas.height = image.naturalHeight;
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let ctx = canvas.getContext("2d");
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ctx.drawImage(image, 0, 0);
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this.startJob(ctx.getImageData(0, 0, canvas.width, canvas.height),
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callback);
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}
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cleanup();
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},
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onImageError: function ColorAnalyzer_onImageError(image, callback, cleanup) {
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Cu.reportError("ColorAnalyzer: image at " + image.src + " didn't load");
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callback.onComplete(false);
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cleanup();
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},
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startJob: function ColorAnalyzer_startJob(imageData, callback) {
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this.callbacks.push(callback);
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this.worker.postMessage({ imageData: imageData, maxColors: 1 });
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},
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onWorkerMessage: function ColorAnalyzer_onWorkerMessage(event) {
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// colors can be empty on failure
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if (event.data.colors.length < 1) {
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this.callbacks.shift().onComplete(false);
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} else {
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this.callbacks.shift().onComplete(true, event.data.colors[0]);
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}
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},
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onWorkerError: function ColorAnalyzer_onWorkerError(error) {
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// this shouldn't happen, but just in case
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error.preventDefault();
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Cu.reportError("ColorAnalyzer worker: " + error.message);
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this.callbacks.shift().onComplete(false);
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},
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classID: Components.ID("{d056186c-28a0-494e-aacc-9e433772b143}"),
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QueryInterface: XPCOMUtils.generateQI([Ci.mozIColorAnalyzer])
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};
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this.NSGetFactory = XPCOMUtils.generateNSGetFactory([ColorAnalyzer]);
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