/*
* Easing functions from ActionScript
* @Implementation: Alexander Gavazov
* @Site: www.creative.bg & www.studio.bg
*/


/*
t - Time value used to compute current value.
b - Starting value.
c - Delta between start and end values.
d - Total length of animation.
*/

var Easing = new Object;

/* Line */

Easing.line = function(t, b, c, d)
{
	return c * t / d + b
}

/* Back */

Easing.backIn = function(t, b, c, d, s)
{
	if(s == undefined)
	{
		s = 1.70158;
	}

	return c * (t /= d) * t * ((s + 1) * t - s) + b;
}

Easing.backOut = function(t, b, c, d, s)
{
	if(s == undefined)
	{
		s = 1.70158;
	}

	return c * ((t = t / d - 1) * t * ((s + 1) * t + s) + 1) + b;
}

Easing.backInOut = function(t, b, c, d, s)
{
	if(s == undefined)
	{
		s = 1.70158;
	}

	if((t /= d / 2) < 1)
	{
		return c / 2 * (t * t * (((s *= (1.525)) + 1) * t - s)) + b;
	}

	return c / 2 * ((t -= 2) * t * (((s *= (1.525)) + 1) * t + s) + 2) + b;
}

/* Bounce */

Easing.bounceIn = function(t, b, c, d)
{
	return c - Easing.bounceOut(d - t, 0, c, d) + b;
}

Easing.bounceOut = function(t, b, c, d)
{
	if((t /= d) < (1 / 2.75))
	{
		return c * (7.5625 * t * t) + b;
	}
	else if(t < (2 / 2.75))
	{
		return c * (7.5625 * (t -= (1.5 / 2.75)) * t + .75) + b;
	}
	else if(t < (2.5 / 2.75))
	{
		return c * (7.5625 * (t -= (2.25 / 2.75)) * t + .9375) + b;
	}
	else
	{
		return c * (7.5625 * (t -= (2.625 / 2.75)) * t + .984375) + b;
	}
}

Easing.bounceInOut = function(t, b, c, d)
{
	return (t < d / 2) ? Easing.bounceIn(t * 2, 0, c, d) * .5 + b : Easing.bounceOut(t * 2 - d, 0, c, d) * .5 + c * .5 + b;
}

/* Circ */

Easing.circIn = function(t, b, c, d)
{
	return -c * (Math.sqrt(1 - (t /= d) * t) - 1) + b;
}

Easing.circOut = function(t, b, c, d)
{
	return c * Math.sqrt(1 - (t = t / d - 1) * t) + b;
}

Easing.circInOut = function(t, b, c, d)
{
	return ((t /= d / 2) < 1) ? -c / 2 * (Math.sqrt(1 - t * t) - 1) + b : c / 2 * (Math.sqrt(1 - (t -= 2) * t) + 1) + b;
}

/* Cubic */

Easing.cubicIn = function(t, b, c, d)
{
	return c * (t /= d) * t * t + b;
}

Easing.cubicOut = function(t, b, c, d)
{
	return c * ((t = t / d - 1) * t * t + 1) + b;
}

Easing.cubicInOut = function(t, b, c, d)
{
	return ((t /= d / 2) < 1) ? c / 2 * t * t * t + b : c / 2 * ((t -= 2) * t * t + 2) + b;
}

/* Elastic */

Easing.elasticIn = function(t, b, c, d)
{
	if(t == 0)
	{
		return b;
	}

	if((t /= d) == 1)
	{
		return b + c;
	}

	if(!p)
	{
		var p = d * .3;
	}

	if(!a || a < Math.abs(c))
	{
		var a = c;
		var s = p / 4;
	}
	else
	{
		var s = p / (2 * Math.PI) * Math.asin (c / a);
	}

	return -(a * Math.pow(2, 10 * (t -= 1)) * Math.sin((t * d - s) * (2 * Math.PI) / p)) + b;
}

Easing.elasticOut = function(t, b, c, d)
{
	if(t == 0)
	{
		return b;
	}

	if((t /= d) == 1)
	{
		return b + c;
	}

	if(!p)
	{
		var p = d * .3;
	}

	if(!a || a < Math.abs(c))
	{
		var a = c;
		var s = p / 4;
	}
	else
	{
		var s = p / (2 * Math.PI) * Math.asin (c / a);
	}

	return (a * Math.pow(2, -10 * t) * Math.sin((t * d - s) * (2 * Math.PI) / p) + c + b);
}

Easing.elasticInOut = function(t, b, c, d)
{
	if(t == 0)
	{
		return b;
	}

	if((t /= d / 2) == 2)
	{
		return b + c;
	}

	if(!p)
	{
		var p = d * (.3 * 1.5);
	}

	if(!a || a < Math.abs(c))
	{
		var a = c;
		var s = p / 4;
	}
	else
	{
		var s = p / (2 * Math.PI) * Math.asin (c / a);
	}

	if(t < 1)
	{
		return -.5 * (a * Math.pow(2, 10 * (t -= 1)) * Math.sin((t * d - s) * (2 * Math.PI) / p)) + b;
	}

	return a * Math.pow(2, -10 * (t -= 1)) * Math.sin((t * d - s) * (2 * Math.PI) / p) * .5 + c + b;
}

/* Expo */

Easing.expoIn = function(t, b, c, d)
{
	return (t == 0) ? b : c * Math.pow(2, 10 * (t / d - 1)) + b;
}

Easing.expoOut = function(t, b, c, d)
{
	return (t == d) ? b + c : c * (-Math.pow(2, -10 * t / d) + 1) + b;
}

Easing.expoInOut = function(t, b, c, d)
{
	if(t == 0)
	{
		return b;
	}

	if(t == d)
	{
		return b + c;
	}

	if((t /= d / 2) < 1)
	{
		return c / 2 * Math.pow(2, 10 * (t - 1)) + b;
	}

	return c / 2 * (-Math.pow(2, -10 * --t) + 2) + b;
}

/* Quad / Regular */

Easing.quadIn = function(t, b, c, d)
{
	return c * (t /= d) * t + b;
}

Easing.quadOut = function(t, b, c, d)
{
	return -c * (t /= d) * (t - 2) + b;
}

Easing.quadInOut = function(t, b, c, d)
{
	return ((t /= d / 2) < 1) ? c / 2 * t * t + b : -c / 2 * ((--t) * (t - 2) - 1) + b;
}

/* Quart */

Easing.quartIn = function(t, b, c, d)
{
	return c * (t /= d) * t * t * t + b;
}

Easing.quartOut = function(t, b, c, d)
{
	return -c * ((t = t / d - 1) * t * t * t - 1) + b;
}

Easing.quartInOut = function(t, b, c, d)
{
	return ((t /= d / 2) < 1) ? c / 2 * t * t * t * t + b : -c / 2 * ((t -= 2) * t * t * t - 2) + b;
}

/* Quint / Strong */

Easing.quintIn = function(t, b, c, d)
{
	return c * (t /= d) * t * t * t * t + b;
}

Easing.quintOut = function(t, b, c, d)
{
	return c * ((t = t / d - 1) * t * t * t * t + 1) + b;
}

Easing.quintInOut = function(t, b, c, d)
{
	return ((t /= d / 2) < 1) ? c / 2 * t * t * t * t * t + b : c / 2 * ((t -= 2) * t * t * t * t + 2) + b;
}

/* Sine */

Easing.sineIn = function(t, b, c, d)
{
	return -c * Math.cos(t / d * (Math.PI / 2)) + c + b;
}

Easing.sineOut = function(t, b, c, d)
{
	return c * Math.sin(t / d * (Math.PI / 2)) + b;
}

Easing.sineInOut = function(t, b, c, d)
{
	return -c / 2 * (Math.cos(Math.PI * t / d) - 1) + b;
}