lenajs.grayscale.js

LenaJS.grayscale = function(pixels, args) {

  for (var i = 0; i < pixels.data.length; i += 4) {

    var r = pixels.data[i],
        g = pixels.data[i+1],
        b = pixels.data[i+2];

    pixels.data[i] = pixels.data[i+1] = pixels.data[i+2] = 0.2126*r + 0.7152*g + 0.0722*b;

  }

  return pixels;
};