function scale(size, ratio, dest) {
  if (dest === undefined) {
    dest = [0, 0];
  }
  dest[0] = (size[0] * ratio + 0.5) | 0;
  dest[1] = (size[1] * ratio + 0.5) | 0;
  return dest;
}
Returns a size scaled by a ratio. The result will be an array of integers.
@param {Size} size Size.
@param {number} ratio Ratio.
@param {Size} [dest] Optional reusable size array.
@return {Size} The scaled size.