function resizeCanvasToDisplaySize(canvas, multiplier) {
	    multiplier = multiplier || 1;
	    multiplier = Math.max(0, multiplier);
	    var width = canvas.clientWidth * multiplier | 0;
	    var height = canvas.clientHeight * multiplier | 0;
	    if (canvas.width !== width || canvas.height !== height) {
	      canvas.width = width;
	      canvas.height = height;
	      return true;
	    }
	    return false;
	  }
Resize a canvas to match the size it's displayed.
@param {HTMLCanvasElement} canvas The canvas to resize.
@param {number} [multiplier] So you can pass in `window.devicePixelRatio` or other scale value if you want to.
@return {boolean} true if the canvas was resized.
@memberOf module:twgl