mirror of
https://github.com/kkapsner/CanvasBlocker
synced 2024-12-22 21:00:23 +01:00
614 lines
19 KiB
JavaScript
614 lines
19 KiB
JavaScript
/* 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/. */
|
|
(function(){
|
|
"use strict";
|
|
|
|
const scope = ((typeof exports) !== "undefined")? exports: require.register("./modifiedCanvasAPI");
|
|
const colorStatistics = require("./colorStatistics");
|
|
const logging = require("./logging");
|
|
const extension = require("./extension");
|
|
const webgl = require("./webgl");
|
|
const {checkerWrapper} = require("./modifiedAPIFunctions");
|
|
|
|
let randomSupply = null;
|
|
|
|
function getContext(window, canvas){
|
|
return window.HTMLCanvasElement.prototype.getContext.call(canvas, "2d") ||
|
|
window.HTMLCanvasElement.prototype.getContext.call(canvas, "webgl") ||
|
|
window.HTMLCanvasElement.prototype.getContext.call(canvas, "experimental-webgl") ||
|
|
window.HTMLCanvasElement.prototype.getContext.call(canvas, "webgl2") ||
|
|
window.HTMLCanvasElement.prototype.getContext.call(canvas, "experimental-webgl2");
|
|
}
|
|
function getImageData(window, context){
|
|
let imageData;
|
|
let source;
|
|
if ((context.canvas.width || 0) * (context.canvas.height || 0) === 0){
|
|
imageData = new (extension.getWrapped(window).ImageData)(0, 0);
|
|
source = new (extension.getWrapped(window).ImageData)(0, 0);
|
|
}
|
|
else if (context instanceof window.CanvasRenderingContext2D){
|
|
imageData = window.CanvasRenderingContext2D.prototype.getImageData.call(
|
|
context,
|
|
0, 0,
|
|
context.canvas.width, context.canvas.height
|
|
);
|
|
source = imageData.data;
|
|
}
|
|
else {
|
|
imageData = new (extension.getWrapped(window).ImageData)(context.canvas.width, context.canvas.height);
|
|
source = new Uint8Array(imageData.data.length);
|
|
(
|
|
context instanceof window.WebGLRenderingContext?
|
|
window.WebGLRenderingContext:
|
|
window.WebGL2RenderingContext
|
|
).prototype.readPixels.call(
|
|
context,
|
|
0, 0, context.canvas.width, context.canvas.height,
|
|
context.RGBA, context.UNSIGNED_BYTE,
|
|
source
|
|
);
|
|
}
|
|
return {
|
|
imageData,
|
|
source
|
|
};
|
|
}
|
|
|
|
const canvasCache = Object.create(null);
|
|
function getFakeCanvas(window, original, prefs){
|
|
try {
|
|
let originalDataURL;
|
|
if (prefs("useCanvasCache")){
|
|
originalDataURL = original.toDataURL();
|
|
const cached = canvasCache[originalDataURL];
|
|
if (cached){
|
|
return cached;
|
|
}
|
|
}
|
|
// original may not be a canvas -> we must not leak an error
|
|
let context = getContext(window, original);
|
|
const {imageData, source} = getImageData(window, context);
|
|
const desc = imageData.data;
|
|
const l = desc.length;
|
|
|
|
let ignoredColors = {};
|
|
let statistic;
|
|
if (prefs("ignoreFrequentColors")){
|
|
statistic = colorStatistics.compute(source);
|
|
ignoredColors = statistic.getMaxColors(prefs("ignoreFrequentColors"));
|
|
}
|
|
if (prefs("minColors")){
|
|
if (!colorStatistics.hasMoreColors(source, prefs("minColors"), statistic)){
|
|
return original;
|
|
}
|
|
}
|
|
|
|
const rng = randomSupply.getPixelRng(l, window, ignoredColors);
|
|
const fakeAlphaChannel = prefs("fakeAlphaChannel");
|
|
for (let i = 0; i < l; i += 4){
|
|
const [r, g, b, a] = rng(
|
|
source[i + 0],
|
|
source[i + 1],
|
|
source[i + 2],
|
|
source[i + 3],
|
|
i / 4
|
|
);
|
|
desc[i + 0] = r;
|
|
desc[i + 1] = g;
|
|
desc[i + 2] = b;
|
|
desc[i + 3] = fakeAlphaChannel? a: source[i + 3];
|
|
}
|
|
const canvas = original.cloneNode(true);
|
|
context = window.HTMLCanvasElement.prototype.getContext.call(canvas, "2d");
|
|
context.putImageData(imageData, 0, 0);
|
|
if (prefs("useCanvasCache")){
|
|
canvasCache[originalDataURL] = canvas;
|
|
canvasCache[canvas.toDataURL()] = canvas;
|
|
}
|
|
return canvas;
|
|
}
|
|
catch (error){
|
|
logging.warning("Error while faking:", error);
|
|
return original;
|
|
}
|
|
}
|
|
function randomMixImageData(window, imageData1, imageData2){
|
|
const data1 = imageData1.data;
|
|
const data2 = imageData2.data;
|
|
const l = data1.length;
|
|
if (l === data2.length){
|
|
const rng = randomSupply.getPixelRng(l, window, {});
|
|
|
|
for (let i = 0; i < l; i += 4){
|
|
const signR = data1[i + 0] > data2[i + 0]? -1: 1;
|
|
const signG = data1[i + 1] > data2[i + 1]? -1: 1;
|
|
const signB = data1[i + 2] > data2[i + 2]? -1: 1;
|
|
const signA = data1[i + 3] > data2[i + 3]? -1: 1;
|
|
|
|
const [deltaR, deltaG, deltaB, deltaA] = rng(
|
|
signR * (data2[i + 0] - data1[i + 0]),
|
|
signG * (data2[i + 1] - data1[i + 1]),
|
|
signB * (data2[i + 2] - data1[i + 2]),
|
|
signA * (data2[i + 3] - data1[i + 3]),
|
|
i / 4
|
|
);
|
|
data2[i + 0] = data1[i + 0] + signR * deltaR;
|
|
data2[i + 1] = data1[i + 1] + signG * deltaG;
|
|
data2[i + 2] = data1[i + 2] + signB * deltaB;
|
|
data2[i + 3] = data1[i + 3] + signA * deltaA;
|
|
}
|
|
}
|
|
return imageData2;
|
|
}
|
|
|
|
function canvasSizeShouldBeFaked(canvas, prefs){
|
|
if (canvas){
|
|
const size = canvas.height * canvas.width;
|
|
const maxSize = prefs("maxFakeSize") || Number.POSITIVE_INFINITY;
|
|
const minSize = prefs("minFakeSize") || 0;
|
|
return size > minSize && size <= maxSize;
|
|
}
|
|
else {
|
|
return true;
|
|
}
|
|
}
|
|
|
|
function getProtectedPartChecker(pref, url){
|
|
const protectedPart = pref("protectedCanvasPart", url);
|
|
if (protectedPart === "everything"){
|
|
return function(){
|
|
return true;
|
|
};
|
|
}
|
|
else if (protectedPart === "nothing"){
|
|
return function(){
|
|
return false;
|
|
};
|
|
}
|
|
else {
|
|
return function(parts){
|
|
if (Array.isArray(parts)){
|
|
return parts.some(function(part){
|
|
return part === protectedPart;
|
|
});
|
|
}
|
|
else {
|
|
return parts === protectedPart;
|
|
}
|
|
};
|
|
}
|
|
}
|
|
|
|
scope.setRandomSupply = function(supply){
|
|
randomSupply = supply;
|
|
webgl.setRandomSupply(supply);
|
|
};
|
|
|
|
const canvasContextType = new WeakMap();
|
|
function createGetStatus(protectedPart){
|
|
if (protectedPart === "readout+"){
|
|
return function(obj, status, prefs){
|
|
const protectedPartChecker = getProtectedPartChecker(prefs, status.url);
|
|
status = Object.create(status);
|
|
status.active = protectedPartChecker("readout");
|
|
if (!status.active && protectedPartChecker("input")){
|
|
const contextType = canvasContextType.get(obj);
|
|
status.active = contextType !== "2d";
|
|
}
|
|
return status;
|
|
};
|
|
}
|
|
return function getStatus(obj, status, prefs){
|
|
const protectedPartChecker = getProtectedPartChecker(prefs, status.url);
|
|
status = Object.create(status);
|
|
status.active = protectedPartChecker(protectedPart);
|
|
return status;
|
|
};
|
|
}
|
|
|
|
function useFakeCanvasCallback(args, check){
|
|
const {prefs, notify, window, original} = check;
|
|
if (canvasSizeShouldBeFaked(this, prefs)){
|
|
const fakeCanvas = getFakeCanvas(window, this, prefs);
|
|
if (fakeCanvas !== this){
|
|
notify("fakedReadout");
|
|
}
|
|
return original.call(fakeCanvas, ...args);
|
|
}
|
|
else {
|
|
return original.call(this, ...args);
|
|
}
|
|
}
|
|
|
|
function mixOnInputCallback(args, check){
|
|
const {prefs, notify, window, original} = check;
|
|
if (!this || canvasSizeShouldBeFaked(this.canvas, prefs)){
|
|
notify("fakedInput");
|
|
let oldImageData;
|
|
let x, y, width, height;
|
|
const getImageData = window.CanvasRenderingContext2D.prototype.getImageData;
|
|
const border = 4;
|
|
try {
|
|
// "this" is not trustable - it may be not a context
|
|
const measurement = window.CanvasRenderingContext2D.prototype.measureText.call(this, args[0]);
|
|
const left = Math.max(0, measurement.actualBoundingBoxLeft);
|
|
const top = Math.max(0, measurement.actualBoundingBoxAscent);
|
|
width = Math.ceil(measurement.actualBoundingBoxRight + left) + 2 * border;
|
|
height = Math.ceil(measurement.actualBoundingBoxDescent + top) + 2 * border;
|
|
x = args[1] - border - left;
|
|
y = args[2] - border - top;
|
|
oldImageData = getImageData.call(this, x, y, width, height);
|
|
}
|
|
catch (error){
|
|
// nothing to do here
|
|
}
|
|
// if "this" is not a correct context the next line will throw an error
|
|
const ret = original.call(this, ...args);
|
|
const newImageData = getImageData.call(this, x, y, width, height);
|
|
this.putImageData(randomMixImageData(window, oldImageData, newImageData), x, y);
|
|
return ret;
|
|
}
|
|
else {
|
|
return original.call(this, ...args);
|
|
}
|
|
}
|
|
|
|
function offscreenToBlobCallback(args, check){
|
|
const {prefs, notify, window, original} = check;
|
|
if (canvasSizeShouldBeFaked(this, prefs)){
|
|
try {
|
|
const canvas = window.document.createElement("canvas");
|
|
canvas.width = this.width;
|
|
canvas.height = this.height;
|
|
const context = canvas.getContext("2d");
|
|
context.drawImage(this.transferToImageBitmap(), 0, 0);
|
|
const fakeCanvas = getFakeCanvas(window, canvas, prefs);
|
|
if (fakeCanvas !== canvas){
|
|
notify("fakedReadout");
|
|
}
|
|
|
|
const fakeContext = getContext(window, fakeCanvas);
|
|
const {imageData} = getImageData(window, fakeContext);
|
|
const fakeOffscreenCanvas = new window.OffscreenCanvas(this.width, this.height);
|
|
const offscreenContext = fakeOffscreenCanvas.getContext("2d");
|
|
offscreenContext.putImageData(imageData, 0, 0);
|
|
return original.call(fakeOffscreenCanvas, ...args);
|
|
}
|
|
catch (error){
|
|
logging.warning("Error while faking:", error);
|
|
return original.call(this, ...args);
|
|
}
|
|
}
|
|
else {
|
|
return original.call(this, ...args);
|
|
}
|
|
}
|
|
|
|
const isPointCache = Object.create(null);
|
|
function getIsPointCacheIndex(x, y, values){
|
|
return String.fromCodePoint(...values, x, y);
|
|
}
|
|
function getIsPointValue({func, x, y, index, originalValue, window, prefs}){
|
|
const useCanvasCache = prefs("useCanvasCache");
|
|
let cacheIndex;
|
|
const values = [originalValue, func(x^1, y), func(x, y^1), func(x^1, y^1)];
|
|
if (useCanvasCache){
|
|
cacheIndex = getIsPointCacheIndex(x, y, values);
|
|
const cached = isPointCache[cacheIndex];
|
|
if ((typeof cached) === "boolean"){
|
|
return cached;
|
|
}
|
|
}
|
|
|
|
const rng = randomSupply.getIndexRng(1, 4, window);
|
|
const res = values[rng(index)];
|
|
|
|
if (useCanvasCache){
|
|
isPointCache[cacheIndex] = res;
|
|
}
|
|
return res;
|
|
}
|
|
|
|
// changed functions and their fakes
|
|
scope.changedFunctions = {
|
|
getContext: {
|
|
type: "context",
|
|
getStatus: function(obj, status, prefs){
|
|
if (status.internal){
|
|
return {
|
|
mode: "allow",
|
|
type: status.type,
|
|
active: false
|
|
};
|
|
}
|
|
else if (getProtectedPartChecker(prefs, status.url)("input")){
|
|
return {
|
|
mode: status.mode,
|
|
type: status.type,
|
|
active: true
|
|
};
|
|
}
|
|
else {
|
|
status = Object.create(status);
|
|
status.active = false;
|
|
return status;
|
|
}
|
|
},
|
|
object: "HTMLCanvasElement",
|
|
fakeGenerator: function(checker){
|
|
return function getContext(context, contextAttributes){
|
|
return checkerWrapper(checker, this, arguments, function(args, check){
|
|
const {original} = check;
|
|
canvasContextType.set(this, context);
|
|
return original.call(this, ...args);
|
|
});
|
|
};
|
|
}
|
|
},
|
|
toDataURL: {
|
|
type: "readout",
|
|
getStatus: createGetStatus("readout+"),
|
|
object: "HTMLCanvasElement",
|
|
fakeGenerator: function(checker){
|
|
return function toDataURL(){
|
|
return checkerWrapper(checker, this, arguments, useFakeCanvasCallback);
|
|
};
|
|
}
|
|
},
|
|
toBlob: {
|
|
type: "readout",
|
|
getStatus: createGetStatus("readout+"),
|
|
object: "HTMLCanvasElement",
|
|
fakeGenerator: function(checker){
|
|
return function toBlob(callback){
|
|
if (this instanceof toBlob){
|
|
throw new extension.getWrapped(window).TypeError(
|
|
"HTMLCanvasElement.prototype.toBlob is not a constructor"
|
|
);
|
|
}
|
|
return checkerWrapper(checker, this, arguments, useFakeCanvasCallback);
|
|
};
|
|
},
|
|
exportOptions: {allowCallbacks: true}
|
|
},
|
|
mozGetAsFile: {
|
|
type: "readout",
|
|
getStatus: createGetStatus("readout+"),
|
|
object: "HTMLCanvasElement",
|
|
fakeGenerator: function(checker){
|
|
return function mozGetAsFile(callback){
|
|
return checkerWrapper(checker, this, arguments, useFakeCanvasCallback);
|
|
};
|
|
},
|
|
exportOptions: {allowCallbacks: true}
|
|
},
|
|
getImageData: {
|
|
type: "readout",
|
|
getStatus: createGetStatus("readout"),
|
|
object: "CanvasRenderingContext2D",
|
|
fakeGenerator: function(checker){
|
|
return function getImageData(sx, sy, sw, sh){
|
|
return checkerWrapper(checker, this, arguments, function(args, check){
|
|
const {prefs, notify, window, original} = check;
|
|
if (!this || canvasSizeShouldBeFaked(this.canvas, prefs)){
|
|
let fakeCanvas;
|
|
let context = this;
|
|
if (this && this.canvas) {
|
|
fakeCanvas = getFakeCanvas(window, this.canvas, prefs);
|
|
}
|
|
if (fakeCanvas && fakeCanvas !== this.canvas){
|
|
notify("fakedReadout");
|
|
context = window.HTMLCanvasElement.prototype.getContext.call(
|
|
fakeCanvas,
|
|
"2d"
|
|
);
|
|
}
|
|
return original.call(context, ...args);
|
|
}
|
|
else {
|
|
return original.call(this, ...args);
|
|
}
|
|
});
|
|
};
|
|
}
|
|
},
|
|
isPointInPath: {
|
|
type: "readout",
|
|
getStatus: createGetStatus("readout"),
|
|
object: "CanvasRenderingContext2D",
|
|
fakeGenerator: function(checker){
|
|
return function isPointInPath(x, y){
|
|
return checkerWrapper(checker, this, arguments, function(args, check){
|
|
const {prefs, notify, window, original} = check;
|
|
const originalValue = original.call(this, ...args);
|
|
if ((typeof originalValue) === "boolean"){
|
|
notify("fakedReadout");
|
|
return getIsPointValue({
|
|
func: (x, y) => original.call(this, x, y, args[2]),
|
|
x, y,
|
|
index: x + this.canvas.width * y,
|
|
originalValue, window, prefs
|
|
});
|
|
}
|
|
else {
|
|
return originalValue;
|
|
}
|
|
});
|
|
};
|
|
}
|
|
},
|
|
isPointInStroke: {
|
|
type: "readout",
|
|
getStatus: createGetStatus("readout"),
|
|
object: "CanvasRenderingContext2D",
|
|
fakeGenerator: function(checker){
|
|
return function isPointInStroke(x, y){
|
|
return checkerWrapper(checker, this, arguments, function(args, check){
|
|
const {prefs, notify, window, original} = check;
|
|
const originalValue = original.call(this, ...args);
|
|
if ((typeof originalValue) === "boolean"){
|
|
notify("fakedReadout");
|
|
let func;
|
|
if (x instanceof window.Path2D){
|
|
let path = x;
|
|
x = y;
|
|
y = args[2];
|
|
func = (x, y) => original.call(this, path, x, y);
|
|
}
|
|
else {
|
|
func = (x, y) => original.call(this, x, y);
|
|
}
|
|
return getIsPointValue({
|
|
func,
|
|
x, y,
|
|
index: x + this.canvas.width * y,
|
|
originalValue, window, prefs
|
|
});
|
|
}
|
|
else {
|
|
return originalValue;
|
|
}
|
|
});
|
|
};
|
|
}
|
|
},
|
|
fillText: {
|
|
type: "input",
|
|
getStatus: createGetStatus("input"),
|
|
object: "CanvasRenderingContext2D",
|
|
fakeGenerator: function(checker){
|
|
return function fillText(str, x, y){
|
|
return checkerWrapper(checker, this, arguments, mixOnInputCallback);
|
|
};
|
|
}
|
|
},
|
|
strokeText: {
|
|
type: "input",
|
|
getStatus: createGetStatus("input"),
|
|
object: "CanvasRenderingContext2D",
|
|
fakeGenerator: function(checker){
|
|
return function strokeText(str, x, y){
|
|
return checkerWrapper(checker, this, arguments, mixOnInputCallback);
|
|
};
|
|
}
|
|
},
|
|
readPixels: {
|
|
type: "readout",
|
|
getStatus: createGetStatus(["readout", "input"]),
|
|
object: ["WebGLRenderingContext", "WebGL2RenderingContext"],
|
|
fakeGenerator: function(checker){
|
|
// eslint-disable-next-line max-params
|
|
return function readPixels(x, y, width, height, format, type, pixels){
|
|
return checkerWrapper(checker, this, arguments, function(args, check){
|
|
const {prefs, notify, window, original} = check;
|
|
if (!this || canvasSizeShouldBeFaked(this.canvas, prefs)){
|
|
notify("fakedReadout");
|
|
const fakeCanvas = getFakeCanvas(window, this.canvas, prefs);
|
|
const {context} = webgl.copyCanvasToWebgl(
|
|
window,
|
|
fakeCanvas,
|
|
this instanceof window.WebGLRenderingContext? "webgl": "webgl2"
|
|
);
|
|
return original.call(context, ...args);
|
|
}
|
|
else {
|
|
return original.call(this, ...args);
|
|
}
|
|
});
|
|
};
|
|
}
|
|
},
|
|
getParameter: {
|
|
type: "readout",
|
|
getStatus: createGetStatus(["readout", "input"]),
|
|
object: ["WebGLRenderingContext", "WebGL2RenderingContext"],
|
|
fakeGenerator: function(checker){
|
|
webgl.initializeParameterDefinitions();
|
|
return function getParameter(pname){
|
|
return checkerWrapper(checker, this, arguments, function(args, check){
|
|
const {prefs, notify, window, original} = check;
|
|
const originalValue = original.call(this, ...args);
|
|
if (webgl.parameterChangeDefinition[pname]){
|
|
const definition = webgl.parameterChangeDefinition[pname];
|
|
const {value, faked} = definition.fake(originalValue, window, prefs);
|
|
if (faked){
|
|
notify("fakedReadout");
|
|
}
|
|
return value;
|
|
}
|
|
else {
|
|
return originalValue;
|
|
}
|
|
});
|
|
};
|
|
}
|
|
},
|
|
getExtension: {
|
|
type: "readout",
|
|
getStatus: createGetStatus(["readout", "input"]),
|
|
object: ["WebGLRenderingContext", "WebGL2RenderingContext"],
|
|
fakeGenerator: function(checker){
|
|
return function getExtension(extensionName){
|
|
return checkerWrapper(checker, this, arguments, function(args, check){
|
|
const {prefs, notify, window, original} = check;
|
|
const originalValue = original.call(this, ...args);
|
|
if (
|
|
extensionName === "WEBGL_debug_renderer_info" &&
|
|
originalValue &&
|
|
webgl.parameterChangeDefinition[originalValue.UNMASKED_VENDOR_WEBGL] &&
|
|
webgl.parameterChangeDefinition[originalValue.UNMASKED_RENDERER_WEBGL]
|
|
){
|
|
const {value: vendorValue, faked: vendorFaked} = webgl
|
|
.parameterChangeDefinition[originalValue.UNMASKED_VENDOR_WEBGL]
|
|
.fake(this.getParameter(originalValue.UNMASKED_VENDOR_WEBGL), window, prefs);
|
|
const {value: rendererValue, faked: rendererFaked} = webgl
|
|
.parameterChangeDefinition[originalValue.UNMASKED_RENDERER_WEBGL]
|
|
.fake(this.getParameter(originalValue.UNMASKED_RENDERER_WEBGL), window, prefs);
|
|
if (
|
|
vendorFaked && vendorValue === null &&
|
|
rendererFaked && rendererValue === null
|
|
){
|
|
const value = null;
|
|
if (originalValue !== value){
|
|
notify("fakedReadout");
|
|
}
|
|
return value;
|
|
}
|
|
else {
|
|
return originalValue;
|
|
}
|
|
}
|
|
else {
|
|
return originalValue;
|
|
}
|
|
});
|
|
};
|
|
}
|
|
},
|
|
convertToBlob: {
|
|
type: "readout",
|
|
getStatus: createGetStatus("readout"),
|
|
object: ["OffscreenCanvas"],
|
|
fakeGenerator: function(checker){
|
|
return function convertToBlob(){
|
|
return checkerWrapper(checker, this, arguments, offscreenToBlobCallback);
|
|
};
|
|
}
|
|
},
|
|
offscreenToBlob: {
|
|
name: "toBlob",
|
|
type: "readout",
|
|
getStatus: createGetStatus("readout"),
|
|
object: ["OffscreenCanvas"],
|
|
fakeGenerator: function(checker){
|
|
return function toBlob(){
|
|
return checkerWrapper(checker, this, arguments, offscreenToBlobCallback);
|
|
};
|
|
}
|
|
},
|
|
};
|
|
Object.keys(scope.changedFunctions).forEach(function(key){
|
|
scope.changedFunctions[key].api = "canvas";
|
|
});
|
|
}()); |