canvas-fuck.js

let cache = {};

let fuck = (canvas) => {
  let key = `${canvas.width},${canvas.height}`;
  let ar = cache[key];
  if (!ar) {
    ar = [];
    for (let i = 0; i < 1000; i++) {
      let pixel = {
        x: Math.round(canvas.width * Math.random()),
        y: Math.round(canvas.height * Math.random()),
        rgba: [Math.random() * 255, Math.random() * 255, Math.random() * 255, 255]
      };
      ar.push(pixel);
    } 
    cache[key] = ar;
  }
  let ctx = canvas.getContext("2d");
  let id = ctx.createImageData(1, 1);
  for (let pixel of ar) {
    let d = id.data;
    for (let i = 0; i < pixel.rgba.length; i++) {
      d[i] = pixel.rgba[i];
    }
    ctx.putImageData(id, pixel.x, pixel.y);  
  }
  console.log(`Fucked with canvas: width=${canvas.width} height=${canvas.height}`);
};

(function(toDataURL) {
  HTMLCanvasElement.prototype.toDataURL = function() {
    let ctx = this.getContext("2d");
    let data;
    if (ctx) {
      fuck(this);
      data = toDataURL.apply(this, arguments);
    }
    let gl = this.getContext("webgl");
    if (gl) {
      let tmpCanvas = document.createElement('canvas');
      tmpCanvas.width = this.width;
      tmpCanvas.height = this.height;
      tmpCanvas.getContext('2d').drawImage(this, 0, 0);
      fuck(tmpCanvas);
      data = toDataURL.apply(tmpCanvas, arguments);
    }
    console.log(data);
    return data;
  };
})(HTMLCanvasElement.prototype.toDataURL);