gsap-custom-ease.js

////////
// CustomEase for GSAP (ES5)
////////

// Written using code from greensock/GreenSock-JS :
// https://github.com/greensock/GreenSock-JS/blob/master/src/uncompressed/easing/EasePack.js

var _gsScope = (typeof(module) !== "undefined" && module.exports && typeof(global) !== "undefined") ? global : this || window; //helps ensure compatibility with AMD/RequireJS and CommonJS/Node
var gs = (_gsScope.GreenSockGlobals || _gsScope).com.greensock;
var CustomEase = gs._class("easing.CustomEase", function(func) {
    this.getRatio = func;
  }, true);
var p = CustomEase.prototype = new Ease();	
p.constructor = CustomEase;
p.config = CustomEase.config = function(steps) {
  return new CustomEase(steps);
};

if (Ease.register)
  Ease.register(CustomEase, "CustomEase", "ease,");


////////
// Usage
////////

// Easing functions examples :
function linearRatio(x) {
  return x;
}
function quadraticEaseInRatio(x) {
  return x * x;
}
function cosineRatio(x) {
  return Math.cos(x * Math.PI)*-0.5 + 0.5);
}

// Get your Easing object :
var CosineEase = CustomEase.config(cosineRatio);

// Use it like your average GSAP Easing:
TweenLite.to($box, 2, { x: 100, ease: CosineEase });

////