lib/easing/easing.js

/*
 * jQuery Easing v1.4.1 - http://gsgd.co.uk/sandbox/jquery/easing/
 * Open source under the BSD License.
 * Copyright © 2008 George McGinley Smith
 * All rights reserved.
 * https://raw.github.com/gdsmith/jquery-easing/master/LICENSE
*/

(function (factory) {
	if (typeof define === "function" && define.amd) {
		define(['jquery'], function ($) {
			return factory($);
		});
	} else if (typeof module === "object" && typeof module.exports === "object") {
		exports = factory(require('jquery'));
	} else {
		factory(jQuery);
	}
})(function($){

// Preserve the original jQuery "swing" easing as "jswing"
if (typeof $.easing !== 'undefined') {
	$.easing['jswing'] = $.easing['swing'];
}

var pow = Math.pow,
	sqrt = Math.sqrt,
	sin = Math.sin,
	cos = Math.cos,
	PI = Math.PI,
	c1 = 1.70158,
	c2 = c1 * 1.525,
	c3 = c1 + 1,
	c4 = ( 2 * PI ) / 3,
	c5 = ( 2 * PI ) / 4.5;

// x is the fraction of animation progress, in the range 0..1
function bounceOut(x) {
	var n1 = 7.5625,
		d1 = 2.75;
	if ( x < 1/d1 ) {
		return n1*x*x;
	} else if ( x < 2/d1 ) {
		return n1*(x-=(1.5/d1))*x + .75;
	} else if ( x < 2.5/d1 ) {
		return n1*(x-=(2.25/d1))*x + .9375;
	} else {
		return n1*(x-=(2.625/d1))*x + .984375;
	}
}

$.extend( $.easing,
{
	def: 'easeOutQuad',
	swing: function (x) {
		return $.easing[$.easing.def](x);
	},
	easeInQuad: function (x) {
		return x * x;
	},
	easeOutQuad: function (x) {
		return 1 - ( 1 - x ) * ( 1 - x );
	},
	easeInOutQuad: function (x) {
		return x < 0.5 ?
			2 * x * x :
			1 - pow( -2 * x + 2, 2 ) / 2;
	},
	easeInCubic: function (x) {
		return x * x * x;
	},
	easeOutCubic: function (x) {
		return 1 - pow( 1 - x, 3 );
	},
	easeInOutCubic: function (x) {
		return x < 0.5 ?
			4 * x * x * x :
			1 - pow( -2 * x + 2, 3 ) / 2;
	},
	easeInQuart: function (x) {
		return x * x * x * x;
	},
	easeOutQuart: function (x) {
		return 1 - pow( 1 - x, 4 );
	},
	easeInOutQuart: function (x) {
		return x < 0.5 ?
			8 * x * x * x * x :
			1 - pow( -2 * x + 2, 4 ) / 2;
	},
	easeInQuint: function (x) {
		return x * x * x * x * x;
	},
	easeOutQuint: function (x) {
		return 1 - pow( 1 - x, 5 );
	},
	easeInOutQuint: function (x) {
		return x < 0.5 ?
			16 * x * x * x * x * x :
			1 - pow( -2 * x + 2, 5 ) / 2;
	},
	easeInSine: function (x) {
		return 1 - cos( x * PI/2 );
	},
	easeOutSine: function (x) {
		return sin( x * PI/2 );
	},
	easeInOutSine: function (x) {
		return -( cos( PI * x ) - 1 ) / 2;
	},
	easeInExpo: function (x) {
		return x === 0 ? 0 : pow( 2, 10 * x - 10 );
	},
	easeOutExpo: function (x) {
		return x === 1 ? 1 : 1 - pow( 2, -10 * x );
	},
	easeInOutExpo: function (x) {
		return x === 0 ? 0 : x === 1 ? 1 : x < 0.5 ?
			pow( 2, 20 * x - 10 ) / 2 :
			( 2 - pow( 2, -20 * x + 10 ) ) / 2;
	},
	easeInCirc: function (x) {
		return 1 - sqrt( 1 - pow( x, 2 ) );
	},
	easeOutCirc: function (x) {
		return sqrt( 1 - pow( x - 1, 2 ) );
	},
	easeInOutCirc: function (x) {
		return x < 0.5 ?
			( 1 - sqrt( 1 - pow( 2 * x, 2 ) ) ) / 2 :
			( sqrt( 1 - pow( -2 * x + 2, 2 ) ) + 1 ) / 2;
	},
	easeInElastic: function (x) {
		return x === 0 ? 0 : x === 1 ? 1 :
			-pow( 2, 10 * x - 10 ) * sin( ( x * 10 - 10.75 ) * c4 );
	},
	easeOutElastic: function (x) {
		return x === 0 ? 0 : x === 1 ? 1 :
			pow( 2, -10 * x ) * sin( ( x * 10 - 0.75 ) * c4 ) + 1;
	},
	easeInOutElastic: function (x) {
		return x === 0 ? 0 : x === 1 ? 1 : x < 0.5 ?
			-( pow( 2, 20 * x - 10 ) * sin( ( 20 * x - 11.125 ) * c5 )) / 2 :
			pow( 2, -20 * x + 10 ) * sin( ( 20 * x - 11.125 ) * c5 ) / 2 + 1;
	},
	easeInBack: function (x) {
		return c3 * x * x * x - c1 * x * x;
	},
	easeOutBack: function (x) {
		return 1 + c3 * pow( x - 1, 3 ) + c1 * pow( x - 1, 2 );
	},
	easeInOutBack: function (x) {
		return x < 0.5 ?
			( pow( 2 * x, 2 ) * ( ( c2 + 1 ) * 2 * x - c2 ) ) / 2 :
			( pow( 2 * x - 2, 2 ) *( ( c2 + 1 ) * ( x * 2 - 2 ) + c2 ) + 2 ) / 2;
	},
	easeInBounce: function (x) {
		return 1 - bounceOut( 1 - x );
	},
	easeOutBounce: bounceOut,
	easeInOutBounce: function (x) {
		return x < 0.5 ?
			( 1 - bounceOut( 1 - 2 * x ) ) / 2 :
			( 1 + bounceOut( 2 * x - 1 ) ) / 2;
	}
});

});