/*
 * raf.js
 * https://github.com/ngryman/raf.js
 *
 * original requestAnimationFrame polyfill by Erik Möller
 * inspired from paul_irish gist and post
 *
 * Copyright (c) 2013 ngryman
 * Licensed under the MIT license.
 */

(function(window) {
	var lastTime = 0,
		vendors = ['webkit', 'moz'],
		requestAnimationFrame = window.requestAnimationFrame,
		cancelAnimationFrame = window.cancelAnimationFrame,
		i = vendors.length;

	// try to un-prefix existing raf
	while (--i >= 0 && !requestAnimationFrame) {
		requestAnimationFrame = window[vendors[i] + 'RequestAnimationFrame'];
		cancelAnimationFrame = window[vendors[i] + 'CancelAnimationFrame'];
	}

	// polyfill with setTimeout fallback
	// heavily inspired from @darius gist mod: https://gist.github.com/paulirish/1579671#comment-837945
	if (!requestAnimationFrame || !cancelAnimationFrame) {
		requestAnimationFrame = function(callback) {
			var now = +new Date(), nextTime = Math.max(lastTime + 16, now);
			return setTimeout(function() {
				callback(lastTime = nextTime);
			}, nextTime - now);
		};

		cancelAnimationFrame = clearTimeout;
	}

	// export to window
	window.requestAnimationFrame = requestAnimationFrame;
	window.cancelAnimationFrame = cancelAnimationFrame;
}(window));