Simple wrapper for requestAnimationFrame that adds fps and stop/resume functionality

animate.js

/*

USAGE:
Pass a function and a fraemrate to the animate function to start. This returns an object with `stop` and `resume` methods.
	
function draw() {
  // do something in here...
}

var animator = animate(draw, 30);

...
animator.stop();

...
animator.resume();

*/
function animate(func, fps) {
	fps = fps || 30;
	var last = Date.now();
	var rafid = false;
	var tick = function() {
	  rafid = requestAnimationFrame(tick);
	  var interval = 1000/fps;
	  var now = Date.now();
	  var elapsed = now - last;
	  if (elapsed > interval) {
	    last = now;
	    func();
	  }
	}
	tick();
	return {
		stop:function() {
			cancelAnimationFrame(rafid);
			rafid = false;
		},
		resume:function() {
			if (rafid === false) 
				tick();
		}
	}
}