http://gsgd.co.uk/sandbox/jquery/easing/
https://github.com/gdsmith/jquery.easing/blob/master/jquery.easing.js
// 緩動函式
// 擴增 jquery.easing 的功能
$.easing['jswing'] = $.easing['swing'];
// x: percent (0 ~ 1)
// t: current time (經過時間 ms)
// b: begInnIng value (0)
// c: change In value (1)
// d: duration (總時間 ms)
$.extend($.easing, {
def: 'easeOutQuad',
ease: function(x, t, b, c, d) {
return $.easing[$.easing.def](x, t, b, c, d);
},
linear: function(x) {
return x;
},
swing: function(x, t, b, c, d) {
//alert(jQuery.easing.default);
return $.easing[$.easing.def](x, t, b, c, d);
},
easeInQuad: function(x, t, b, c, d) {
return c * (t /= d) * t + b;
},
easeOutQuad: function(x, t, b, c, d) {
var result = -c * (t /= d) * (t - 2) + b;
return result;
},
easeInOutQuad: function(x, t, b, c, d) {
if ((t /= d / 2) < 1)
return c / 2 * t * t + b;
return -c / 2 * ((--t) * (t - 2) - 1) + b;
},
easeInCubic: function(x, t, b, c, d) {
return c * (t /= d) * t * t + b;
},
easeOutCubic: function(x, t, b, c, d) {
return c * ((t = t / d - 1) * t * t + 1) + b;
},
easeInOutCubic: function(x, t, b, c, d) {
if ((t /= d / 2) < 1)
return c / 2 * t * t * t + b;
return c / 2 * ((t -= 2) * t * t + 2) + b;
},
easeInQuart: function(x, t, b, c, d) {
return c * (t /= d) * t * t * t + b;
},
easeOutQuart: function(x, t, b, c, d) {
return -c * ((t = t / d - 1) * t * t * t - 1) + b;
},
easeInOutQuart: function(x, t, b, c, d) {
if ((t /= d / 2) < 1)
return c / 2 * t * t * t * t + b;
return -c / 2 * ((t -= 2) * t * t * t - 2) + b;
},
easeInQuint: function(x, t, b, c, d) {
return c * (t /= d) * t * t * t * t + b;
},
easeOutQuint: function(x, t, b, c, d) {
return c * ((t = t / d - 1) * t * t * t * t + 1) + b;
},
easeInOutQuint: function(x, t, b, c, d) {
if ((t /= d / 2) < 1)
return c / 2 * t * t * t * t * t + b;
return c / 2 * ((t -= 2) * t * t * t * t + 2) + b;
},
easeInSine: function(x, t, b, c, d) {
// console.dir(arguments);
var result = -c * Math.cos(t / d * (Math.PI / 2)) + c + b;
return result;
},
easeOutSine: function(x, t, b, c, d) {
return c * Math.sin(t / d * (Math.PI / 2)) + b;
},
easeInOutSine: function(x, t, b, c, d) {
return -c / 2 * (Math.cos(Math.PI * t / d) - 1) + b;
},
easeInExpo: function(x, t, b, c, d) {
return (t == 0) ? b : c * Math.pow(2, 10 * (t / d - 1)) + b;
},
easeOutExpo: function(x, t, b, c, d) {
return (t == d) ? b + c : c * (-Math.pow(2, -10 * t / d) + 1) + b;
},
easeInOutExpo: function(x, 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;
},
easeInCirc: function(x, t, b, c, d) {
return -c * (Math.sqrt(1 - (t /= d) * t) - 1) + b;
},
easeOutCirc: function(x, t, b, c, d) {
return c * Math.sqrt(1 - (t = t / d - 1) * t) + b;
},
easeInOutCirc: function(x, t, b, c, d) {
if ((t /= d / 2) < 1)
return -c / 2 * (Math.sqrt(1 - t * t) - 1) + b;
return c / 2 * (Math.sqrt(1 - (t -= 2) * t) + 1) + b;
},
easeInElastic: function(x, t, b, c, d) {
var s = 1.70158;
var p = 0;
var a = c;
if (t == 0)
return b;
if ((t /= d) == 1)
return b + c;
if (!p)
p = d * .3;
if (a < Math.abs(c)) {
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;
},
easeOutElastic: function(x, t, b, c, d) {
var s = 1.70158;
var p = 0;
var a = c;
if (t == 0)
return b;
if ((t /= d) == 1)
return b + c;
if (!p)
p = d * .3;
if (a < Math.abs(c)) {
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;
},
easeInOutElastic: function(x, t, b, c, d) {
var s = 1.70158;
var p = 0;
var a = c;
if (t == 0)
return b;
if ((t /= d / 2) == 2)
return b + c;
if (!p)
p = d * (.3 * 1.5);
if (a < Math.abs(c)) {
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;
},
easeInBack: function(x, t, b, c, d, s) {
if (s == undefined)
s = 1.70158;
return c * (t /= d) * t * ((s + 1) * t - s) + b;
},
easeOutBack: function(x, t, b, c, d, s) {
if (s == undefined)
s = 1.70158;
return c * ((t = t / d - 1) * t * ((s + 1) * t + s) + 1) + b;
},
easeInOutBack: function(x, 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;
},
easeInBounce: function(x, t, b, c, d) {
return c - $.easing.easeOutBounce(x, d - t, 0, c, d) + b;
},
easeOutBounce: function(x, 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;
}
},
easeInOutBounce: function(x, t, b, c, d) {
if (t < d / 2)
return $.easing.easeInBounce(x, t * 2, 0, c, d) * .5 + b;
return $.easing.easeOutBounce(x, t * 2 - d, 0, c, d) * .5 + c * .5 + b;
}
});
