js.缓冲运动封装函数

//缓冲的各种公式
    var Tween = { 
        Linear: function(t, b, c, d) {
            return c * t / d + b;
        },
        //二次的
        QuadEaseIn: function(t, b, c, d) {
            return c * (t /= d) * t + b;
        },
        QuadEaseOut: function(t, b, c, d) {
            return -c * (t /= d) * (t - 2) + b;
        },
        QuadEaseInOut: function(t, b, c, d) {
            if ((t /= d / 2) < 1) return c / 2 * t * t + b;
            return -c / 2 * ((--t) * (t - 2) - 1) + b;
        },
        //三次的
        CubicEaseIn: function(t, b, c, d) {
            return c * (t /= d) * t * t + b;
        },
        CubicEaseOut: function(t, b, c, d) {
            return c * ((t = t / d - 1) * t * t + 1) + b;
        },
        CubicEaseInOut: function(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;
        },
        //四次的
        QuartEaseIn: function(t, b, c, d) {
            return c * (t /= d) * t * t * t + b;
        },
        QuartEaseOut: function(t, b, c, d) {
            return -c * ((t = t / d - 1) * t * t * t - 1) + b;
        },
        QuartEaseInOut: function(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;
        },
        QuartEaseIn: function(t, b, c, d) {
            return c * (t /= d) * t * t * t * t + b;
        },
        QuartEaseOut: function(t, b, c, d) {
            return c * ((t = t / d - 1) * t * t * t * t + 1) + b;
        },
        QuartEaseInOut: function(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;
        },
        //正弦的
        SineEaseIn: function(t, b, c, d) {
            return -c * Math.cos(t / d * (Math.PI / 2)) + c + b;
        },
        SineEaseOut: function(t, b, c, d) {
            return c * Math.sin(t / d * (Math.PI / 2)) + b;
        },
        SineEaseInOut: function(t, b, c, d) {
            return -c / 2 * (Math.cos(Math.PI * t / d) - 1) + b;
        },
        ExpoEaseIn: function(t, b, c, d) {
            return (t == 0) ? b : c * Math.pow(2, 10 * (t / d - 1)) + b;
        },
        ExpoEaseOut: function(t, b, c, d) {
            return (t == d) ? b + c : c * (-Math.pow(2, -10 * t / d) + 1) + b;
        },
        ExpoEaseInOut: 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;
        },
        CircEaseIn: function(t, b, c, d) {
            return -c * (Math.sqrt(1 - (t /= d) * t) - 1) + b;
        },
        CircEaseOut: function(t, b, c, d) {
            return c * Math.sqrt(1 - (t = t / d - 1) * t) + b;
        },
        CircEaseInOut: function(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;
        },
        ElasticEaseIn: function(t, b, c, d, a, p) {
            if (t == 0) return b;
            if ((t /= d) == 1) return b + c;
            if (!p) p = d * .3;
            if (!a || 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;
        },
        ElasticEaseOut: function(t, b, c, d, a, p) {
            if (t == 0) return b;
            if ((t /= d) == 1) return b + c;
            if (!p) p = d * .3;
            if (!a || 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);
        },
        ElasticEaseInOut: function(t, b, c, d, a, p) {
            if (t == 0) return b;
            if ((t /= d / 2) == 2) return b + c;
            if (!p) p = d * (.3 * 1.5);
            if (!a || 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;
        },
        //冲过头系列
        BackEaseIn: function(t, b, c, d, s) {
            if (s == undefined) s = 1.70158;
            return c * (t /= d) * t * ((s + 1) * t - s) + b;
        },
        BackEaseOut: 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;
        },
        BackEaseInOut: 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;
        },
        //弹跳系列
        BounceEaseIn: function(t, b, c, d) {
            return c - Tween.BounceEaseOut(d - t, 0, c, d) + b;
        },
        BounceEaseOut: 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;
            }
        },
        BounceEaseInOut: function(t, b, c, d) {
            if (t < d / 2) return Tween.BounceEaseIn(t * 2, 0, c, d) * .5 + b;
            else return Tween.BounceEaseOut(t * 2 - d, 0, c, d) * .5 + c * .5 + b;
        }
    };
}