forked from WolfspiritM/AntiCF
/
anticanvas.js
61 lines (46 loc) · 1.67 KB
/
anticanvas.js
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// ==UserScript==
// @name Anti Canvas Fingerprint
// @version 0.1
// @description Changes Images prior to Export via DataURL or getImageData.
// @match *://*/*
// @run-at document-start
// @copyright 2014+, AB
// ==/UserScript==
(function(){
CanvasRenderingContext2D.prototype.getImageData = function(a) {
return function() {
console.log("Context");
spoofFromContext(this,a);
return a.apply(this, arguments);
};
}(CanvasRenderingContext2D.prototype.getImageData);
HTMLCanvasElement.prototype.toDataURL=(function(){
var original = HTMLCanvasElement.prototype.toDataURL;
return function() {
spoof(this);
return original.apply(this,arguments);
};
})();
function spoof(canvas){
var ctx = canvas.getContext("2d");
spoofFromContext(ctx);
}
function spoofFromContext(ctx,a){
if(!a) a = ctx.getImageData;
var data = a.call(ctx,0, 0, ctx.canvas.width, ctx.canvas.height);
for(var c=0; c<data.data.length; c=c+4){
var r = data.data[c];
var g = data.data[c+1];
var b = data.data[c+2];
var a = data.data[c+3];
if(a!=0){
data.data[c]=r-Math.random();
data.data[c+1]=g-Math.random();
data.data[c+2]=b-Math.random();
data.data[c+3]=a-Math.random();
}
}
ctx.putImageData(data, 0, 0);
console.log("Spoofed");
}
})();