Easing function

easeInOutQuad.js

// Different structure of an easing formula from https://github.com/danro/jquery-easing/blob/master/jquery.easing.js for better understanding

function easeInOutQuad (currentTime, duration, fromValue, toValue) {
	var t = currentTime;
	var b = fromValue;
	var c = toValue - fromValue;
	var d = duration;
	if ((t/=d/2) < 1) return c/2*t*t + b;
	return -c/2 * ((--t)*(t-2) - 1) + b;
}