mirror of
https://github.com/kkapsner/CanvasBlocker
synced 2024-11-04 20:28:52 +01:00
395 lines
12 KiB
JavaScript
395 lines
12 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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(function(){
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"use strict";
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var scope;
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if ((typeof exports) !== "undefined"){
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scope = exports;
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}
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else {
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window.scope.modifiedAPI = {};
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scope = window.scope.modifiedAPI;
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}
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const colorStatistics = require("./colorStatistics");
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const logging = require("./logging");
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const {copyCanvasToWebgl} = require("./webgl");
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const getWrapped = require("sdk/getWrapped");
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var randomSupply = null;
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function getContext(window, canvas){
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return window.HTMLCanvasElement.prototype.getContext.call(canvas, "2d") ||
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window.HTMLCanvasElement.prototype.getContext.call(canvas, "webgl") ||
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window.HTMLCanvasElement.prototype.getContext.call(canvas, "experimental-webgl") ||
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window.HTMLCanvasElement.prototype.getContext.call(canvas, "webgl2") ||
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window.HTMLCanvasElement.prototype.getContext.call(canvas, "experimental-webgl2");
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}
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function getImageData(window, context){
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var imageData;
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var source;
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if ((context.canvas.width || 0) * (context.canvas.height || 0) === 0){
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imageData = new (getWrapped(window).ImageData)(0, 0);
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source = new (getWrapped(window).ImageData)(0, 0);
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}
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else if (context instanceof window.CanvasRenderingContext2D){
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imageData = window.CanvasRenderingContext2D.prototype.getImageData.call(
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context,
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0, 0,
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context.canvas.width, context.canvas.height
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);
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source = imageData.data;
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}
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else {
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imageData = new (getWrapped(window).ImageData)(context.canvas.width, context.canvas.height);
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source = new Uint8Array(imageData.data.length);
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(
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context instanceof window.WebGLRenderingContext?
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window.WebGLRenderingContext:
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window.WebGL2RenderingContext
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).prototype.readPixels.call(
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context,
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0, 0, context.canvas.width, context.canvas.height,
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context.RGBA, context.UNSIGNED_BYTE,
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source
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);
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}
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return {
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imageData,
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source
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};
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}
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var canvasCache = Object.create(null);
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function getFakeCanvas(window, original, prefs){
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try {
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if (prefs("useCanvasCache")){
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var originalDataURL = original.toDataURL();
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var cached = canvasCache[originalDataURL];
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if (cached){
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return cached;
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}
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}
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// original may not be a canvas -> we must not leak an error
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var context = getContext(window, original);
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var {imageData, source} = getImageData(window, context);
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var desc = imageData.data;
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var l = desc.length;
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var ignoredColors = {};
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if (prefs("ignoreFrequentColors")){
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var statistic = colorStatistics.compute(source);
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ignoredColors = statistic.getMaxColors(prefs("ignoreFrequentColors"));
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}
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var rng = randomSupply.getPixelRng(l, window, ignoredColors);
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var fakeAlphaChannel = prefs("fakeAlphaChannel");
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for (var i = 0; i < l; i += 4){
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var [r, g, b, a] = rng(
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source[i + 0],
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source[i + 1],
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source[i + 2],
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source[i + 3],
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i / 4
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);
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desc[i + 0] = r;
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desc[i + 1] = g;
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desc[i + 2] = b;
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desc[i + 3] = fakeAlphaChannel? a: source[i + 3];
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}
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var canvas = original.cloneNode(true);
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context = window.HTMLCanvasElement.prototype.getContext.call(canvas, "2d");
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context.putImageData(imageData, 0, 0);
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if (prefs("useCanvasCache")){
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canvasCache[originalDataURL] = canvas;
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canvasCache[canvas.toDataURL()] = canvas;
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}
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return canvas;
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}
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catch (e){
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logging.warning("Error while faking:", e);
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return original;
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}
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}
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function randomMixImageData(window, imageData1, imageData2){
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var data1 = imageData1.data;
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var data2 = imageData2.data;
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var l = data1.length;
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if (l === data2.length){
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var rng = randomSupply.getRng(l, window);
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for (var i = 0; i < l; i += 1){
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if (data1[i] > data2[i]){
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data2[i] = data1[i] - rng(data1[i] - data2[i], i);
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}
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else if (data1[i] < data2[i]){
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data2[i] = data1[i] + rng(data2[i] - data1[i], i);
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}
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}
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}
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return imageData2;
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}
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function canvasSizeShouldBeFaked(canvas, prefs){
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if (canvas){
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var size = canvas.height * canvas.width;
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var maxSize = prefs("maxFakeSize") || Number.POSITIVE_INFINITY;
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var minSize = prefs("minFakeSize") || 0;
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return size > minSize & size <= maxSize;
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}
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else {
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return true;
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}
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}
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function hasType(status, type){
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return status.type.indexOf(type) !== -1;
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}
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scope.setRandomSupply = function(supply){
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randomSupply = supply;
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};
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var canvasContextType = new WeakMap();
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// changed functions and their fakes
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scope.changedFunctions = {
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getContext: {
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type: "context",
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getStatus: function(obj, status){
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if (hasType(status, "internal")){
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return {
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mode: "allow",
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type: status.type,
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active: false
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};
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}
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else if (hasType(status, "context") || hasType(status, "input")){
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return {
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mode: (status.mode === "block")? "block": "fake",
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type: status.type,
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active: true
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};
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}
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else {
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status = Object.create(status);
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status.active = false;
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return status;
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}
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},
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object: "HTMLCanvasElement",
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fakeGenerator: function(prefs, notify, window, original){
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return function(context, contextAttributes){
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canvasContextType.set(this, context);
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return original.apply(this, window.Array.from(arguments));
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};
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}
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},
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toDataURL: {
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type: "readout",
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getStatus: function(obj, status){
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status = Object.create(status);
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if (hasType(status, "input")){
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var contextType = canvasContextType.get(obj);
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status.active = contextType !== "2d";
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}
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else {
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status.active = hasType(status, "readout");
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}
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return status;
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},
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object: "HTMLCanvasElement",
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fakeGenerator: function(prefs, notify, window, original){
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return function toDataURL(){
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if (canvasSizeShouldBeFaked(this, prefs)){
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notify.call(this, "fakedReadout");
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return original.apply(getFakeCanvas(window, this, prefs), window.Array.from(arguments));
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}
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else {
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return original.apply(this, window.Array.from(arguments));
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}
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};
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}
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},
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toBlob: {
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type: "readout",
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getStatus: function(obj, status){
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status = Object.create(status);
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if (hasType(status, "input")){
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var contextType = canvasContextType.get(obj);
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status.active = contextType !== "2d";
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}
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else {
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status.active = hasType(status, "readout");
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}
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return status;
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},
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object: "HTMLCanvasElement",
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fakeGenerator: function(prefs, notify, window, original){
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return function toBlob(callback){
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if (canvasSizeShouldBeFaked(this, prefs)){
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notify.call(this, "fakedReadout");
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return original.apply(getFakeCanvas(window, this, prefs), window.Array.from(arguments));
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}
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else {
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return original.apply(this, window.Array.from(arguments));
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}
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};
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},
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exportOptions: {allowCallbacks: true}
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},
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mozGetAsFile: {
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type: "readout",
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getStatus: function(obj, status){
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status = Object.create(status);
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if (hasType(status, "input")){
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var contextType = canvasContextType.get(obj);
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status.active = contextType !== "2d";
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}
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else {
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status.active = hasType(status, "readout");
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}
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return status;
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},
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object: "HTMLCanvasElement",
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fakeGenerator: function(prefs, notify, window, original){
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return function mozGetAsFile(callback){
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if (canvasSizeShouldBeFaked(this, prefs)){
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notify.call(this, "fakedReadout");
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return original.apply(getFakeCanvas(window, this, prefs), window.Array.from(arguments));
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}
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else {
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return original.apply(this, window.Array.from(arguments));
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}
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};
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}
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},
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getImageData: {
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type: "readout",
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getStatus: function(obj, status){
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status = Object.create(status);
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if (hasType(status, "input")){
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var contextType = canvasContextType.get(obj && obj.canvas);
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status.active = contextType !== "2d";
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}
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else {
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status.active = hasType(status, "readout");
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}
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return status;
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},
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object: "CanvasRenderingContext2D",
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fakeGenerator: function(prefs, notify, window, original){
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return function getImageData(sx, sy, sw, sh){
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if (!this || canvasSizeShouldBeFaked(this.canvas, prefs)){
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notify.call(this, "fakedReadout");
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var fakeCanvas;
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var context = this;
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if (this && this.canvas) {
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fakeCanvas = getFakeCanvas(window, this.canvas, prefs);
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}
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if (fakeCanvas && fakeCanvas !== this.canvas){
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context = window.HTMLCanvasElement.prototype.getContext.call(
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fakeCanvas,
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"2d"
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);
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}
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return original.apply(context, window.Array.from(arguments));
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}
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else {
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return original.apply(this, window.Array.from(arguments));
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}
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};
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}
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},
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fillText: {
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type: "input",
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getStatus: function(obj, status){
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status = Object.create(status);
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status.active = hasType(status, "input");
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return status;
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},
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object: "CanvasRenderingContext2D",
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fakeGenerator: function(prefs, notify, window, original){
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return function fillText(str, x, y){
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if (!this || canvasSizeShouldBeFaked(this.canvas, prefs)){
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notify.call(this, "fakedInput");
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var oldImageData;
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try {
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// "this" is not trustable - it may be not a context
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oldImageData = getImageData(window, this).imageData;
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}
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catch (e){
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// nothing to do here
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}
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// if "this" is not a correct context the next line will throw an error
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var ret = original.apply(this, window.Array.from(arguments));
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var newImageData = getImageData(window, this).imageData;
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this.putImageData(randomMixImageData(window, oldImageData, newImageData), 0, 0);
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return ret;
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}
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else {
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return original.apply(this, window.Array.from(arguments));
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}
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};
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}
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},
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strokeText: {
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type: "input",
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getStatus: function(obj, status){
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status = Object.create(status);
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status.active = hasType(status, "input");
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return status;
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},
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object: "CanvasRenderingContext2D",
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fakeGenerator: function(prefs, notify, window, original){
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return function strokeText(str, x, y){
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if (!this || canvasSizeShouldBeFaked(this.canvas, prefs)){
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notify.call(this, "fakedInput");
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var oldImageData;
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try {
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// "this" is not trustable - it may be not a context
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oldImageData = getImageData(window, this).imageData;
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}
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catch (e){
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// nothing to do here
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}
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// if "this" is not a correct context the next line will throw an error
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var ret = original.apply(this, window.Array.from(arguments));
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var newImageData = getImageData(window, this).imageData;
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this.putImageData(randomMixImageData(window, oldImageData, newImageData), 0, 0);
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return ret;
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}
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else {
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return original.apply(this, window.Array.from(arguments));
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}
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};
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}
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},
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readPixels: {
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type: "readout",
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getStatus: function(obj, status){
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status = Object.create(status);
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status.active = hasType(status, "readout") || hasType(status, "input");
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return status;
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},
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object: ["WebGLRenderingContext", "WebGL2RenderingContext"],
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fakeGenerator: function(prefs, notify, window, original){
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return function readPixels(x, y, width, height, format, type, pixels){ // eslint-disable-line max-params
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if (!this || canvasSizeShouldBeFaked(this.canvas, prefs)){
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notify.call(this, "fakedReadout");
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var fakeCanvas = getFakeCanvas(window, this.canvas, prefs);
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var {context} = copyCanvasToWebgl(
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window,
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fakeCanvas,
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this instanceof window.WebGLRenderingContext? "webgl": "webgl2"
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);
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return original.apply(context, window.Array.from(arguments));
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}
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else {
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return original.apply(this, window.Array.from(arguments));
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}
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};
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}
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}
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};
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}()); |