mirror of
https://github.com/kkapsner/CanvasBlocker
synced 2024-10-31 18:38:45 +01:00
ec128796e3
Fixes #448
96 lines
3.3 KiB
JavaScript
96 lines
3.3 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";
|
|
|
|
let scope;
|
|
if ((typeof exports) !== "undefined"){
|
|
scope = exports;
|
|
}
|
|
else {
|
|
scope = require.register("./modifiedTextMetricsAPI", {});
|
|
}
|
|
|
|
const {checkerWrapper, setProperties, getStatusByFlag} = require("./modifiedAPIFunctions");
|
|
const {byteArrayToString: hash} = require("./hash");
|
|
const {cache} = require("./modifiedDOMRectAPI");
|
|
const valueCache = cache.valueCache;
|
|
|
|
function getValueHash(value){
|
|
return hash(new Float32Array([value]));
|
|
}
|
|
|
|
let randomSupply = null;
|
|
scope.setRandomSupply = function(supply){
|
|
randomSupply = supply;
|
|
};
|
|
|
|
function getFakeValue(window, value, i, prefs){
|
|
const valueHash = getValueHash(value);
|
|
const cache = valueCache[i];
|
|
let cachedValue = cache[valueHash];
|
|
if (typeof cachedValue === "number"){
|
|
return cachedValue;
|
|
}
|
|
if ((value * prefs("domRectIntegerFactor", window.location)) % 1 === 0){
|
|
cache[valueHash] = value;
|
|
return value;
|
|
}
|
|
else {
|
|
const rng = randomSupply.getRng(5, window);
|
|
const fakedValue = value + 0.01 * (rng(i) / 0xffffffff - 0.5);
|
|
const fakedHash = getValueHash(fakedValue);
|
|
cache[valueHash] = fakedValue;
|
|
cache[fakedHash] = fakedValue;
|
|
return fakedValue;
|
|
}
|
|
}
|
|
|
|
function generateChangedTextMetricsPropertyGetter(property, cacheIndex){
|
|
const changedGetter = {
|
|
objectGetters: [
|
|
function(window){return window.TextMetrics && window.TextMetrics.prototype;}
|
|
],
|
|
name: property,
|
|
getterGenerator: function(checker){
|
|
const temp = {
|
|
get [property](){
|
|
return checkerWrapper(checker, this, arguments, function(args, check){
|
|
const {prefs, notify, window, original} = check;
|
|
const originalValue = original.call(this, ...args);
|
|
const returnValue = getFakeValue(window, originalValue, cacheIndex, prefs);
|
|
if (originalValue !== returnValue){
|
|
notify("fakedTextMetricsReadout");
|
|
}
|
|
return returnValue;
|
|
});
|
|
}
|
|
};
|
|
return Object.getOwnPropertyDescriptor(temp, property).get;
|
|
}
|
|
};
|
|
return changedGetter;
|
|
}
|
|
|
|
scope.changedGetters = [
|
|
generateChangedTextMetricsPropertyGetter("width", cache.WIDTH),
|
|
generateChangedTextMetricsPropertyGetter("actualBoundingBoxAscent", cache.OTHER),
|
|
generateChangedTextMetricsPropertyGetter("actualBoundingBoxDescent", cache.OTHER),
|
|
generateChangedTextMetricsPropertyGetter("actualBoundingBoxLeft", cache.OTHER),
|
|
generateChangedTextMetricsPropertyGetter("actualBoundingBoxRight", cache.OTHER),
|
|
generateChangedTextMetricsPropertyGetter("alphabeticBaseline", cache.OTHER),
|
|
generateChangedTextMetricsPropertyGetter("emHeightAscent", cache.OTHER),
|
|
generateChangedTextMetricsPropertyGetter("emHeightDescent", cache.OTHER),
|
|
generateChangedTextMetricsPropertyGetter("fontBoundingBoxAscent", cache.OTHER),
|
|
generateChangedTextMetricsPropertyGetter("fontBoundingBoxDescent", cache.OTHER),
|
|
generateChangedTextMetricsPropertyGetter("hangingBaseline", cache.OTHER),
|
|
generateChangedTextMetricsPropertyGetter("ideographicBaseline", cache.OTHER),
|
|
];
|
|
|
|
setProperties({}, scope.changedGetters, {
|
|
type: "readout",
|
|
getStatus: getStatusByFlag("protectTextMetrics"),
|
|
api: "textMetrics"
|
|
});
|
|
}()); |