code: function readPixel(png, x, y) {
    if(x < 0 || y <0 || x > png.width || y > png.height)
      return null;
  
    var idx = (png.width * y + x) << 2;
    var background = [png.data[idx], png.data[idx+1], png.data[idx+2], png.data[idx+3]];
    return background;
  }
docs: /*
  Gets the color of the pixel at the given coordinates.
  
  @param {int} x The x coordinate of the pixel
  @param {int} y The y coordinate of the pixel
  @return {Array(byte)} The color of the pixel, or null if coordinates are not in image bounds.