/**
* Contains various methods that can be used when you are wanting to ease a Tween.
* 
* @module Tweens
* @submodule Easing 
* @main Easing
*/

module Kiwi.Animations.Tweens.Easing {

	/**
	* 
	* @class Back
	* @namespace Kiwi.Animations.Tweens.Easing
	* 
	*/
	export class Back {

		/**
		* The type of object this is.
		* @method objType
		* @return {String} "Back"
		* @public
		*/
		public objType() {
			return "Back";
		}

		/** 
		* 
		* @method In
		* @param k {Any}
		* @return {Number}
		* @static
		* @public
		*/
		public static In(k) {

			var s = 1.70158;
			return k * k * ((s + 1) * k - s);

		}

		/** 
		* 
		* @method Out
		* @param {Any} k
		* @return {Number}
		* @static
		* @public
		*/
		public static Out(k) {

			var s = 1.70158;
			return --k * k * ((s + 1) * k + s) + 1;

		}

		/** 
		* 
		* @method InOut
		* @param k {Any}
		* @return {Number}
		* @static
		* @public
		*/
		public static InOut(k) {

			var s = 1.70158 * 1.525;
			if ((k *= 2) < 1) return 0.5 * (k * k * ((s + 1) * k - s));
			return 0.5 * ((k -= 2) * k * ((s + 1) * k + s) + 2);

		}

	}

}