tween路径计算函数

//obj运动对象
//attr运动元素
//target运动目标点
//duration 运动时间
//fx 运动方式
//callBack回调函数
 
function mTween(obj,attr,target,duration,fx,callBack){
    //获取起始位置
    var begin = parseFloat(getComputedStyle(obj)[attr]);
    //算出总距离
    var count = target - begin;
    //var time = new Date().getTime();
    //记录时间
    var time = +new Date();
    //防止定时器冲突，所以每次开启先清除。
    clearInterval(obj[attr])
    obj[attr] = setInterval(function(){
        //获取已过去的时间
        var t = +new Date() - time ;
        // console.log(1);
        //已过去时间超出总时间代表运动结束
        if(t>=duration){
            t = duration;
            //清除定时器
            clearInterval(obj[attr]);
             
        }
        //var value = count*t/duration + begin;
        //根据传入的运动方式算出obj应该运动的值
        var value = Tween[fx](t,begin,count,duration);
         
        obj.style[attr] = value + 'px';
         
        if(t == duration){
            //如果有回调函数就执行回调
            callBack&&callBack();
        }
    },16)
}

/*
* t : time 已过时间
* b : begin 起始值
* c : count 总的运动值
* d : duration 持续时间
*
* 曲线方程
*
* http://www.cnblogs.com/bluedream2009/archive/2010/06/19/1760909.html
* */
 /**
 * @param {number} t 已过时间
 * @param {number} b 起始值
 * @param {number} c 总的运动值
 * @param {number} d 持续时间
 */
var tweenPathFunc = {
  Linear: function(t, b, c, d) {
    return (c * t) / d + b;
  },
  Quad: {
    easeIn: function(t, b, c, d) {
      return c * (t /= d) * t + b;
    },
    easeOut: function(t, b, c, d) {
      return -c * (t /= d) * (t - 2) + b;
    },
    easeInOut: function(t, b, c, d) {
      if ((t /= d / 2) < 1) return (c / 2) * t * t + b;
      return (-c / 2) * (--t * (t - 2) - 1) + b;
    }
  },
  Cubic: {
    easeIn: function(t, b, c, d) {
      return c * (t /= d) * t * t + b;
    },
    easeOut: function(t, b, c, d) {
      return c * ((t = t / d - 1) * t * t + 1) + b;
    },
    easeInOut: 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;
    }
  },
  Quart: {
    easeIn: function(t, b, c, d) {
      return c * (t /= d) * t * t * t + b;
    },
    easeOut: function(t, b, c, d) {
      return -c * ((t = t / d - 1) * t * t * t - 1) + b;
    },
    easeInOut: 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;
    }
  },
  Quint: {
    easeIn: function(t, b, c, d) {
      return c * (t /= d) * t * t * t * t + b;
    },
    easeOut: function(t, b, c, d) {
      return c * ((t = t / d - 1) * t * t * t * t + 1) + b;
    },
    easeInOut: 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;
    }
  },
  Sine: {
    easeIn: function(t, b, c, d) {
      return -c * Math.cos((t / d) * (Math.PI / 2)) + c + b;
    },
    easeOut: function(t, b, c, d) {
      return c * Math.sin((t / d) * (Math.PI / 2)) + b;
    },
    easeInOut: function(t, b, c, d) {
      return (-c / 2) * (Math.cos((Math.PI * t) / d) - 1) + b;
    }
  },
  Expo: {
    easeIn: function(t, b, c, d) {
      return t == 0 ? b : c * Math.pow(2, 10 * (t / d - 1)) + b;
    },
    easeOut: function(t, b, c, d) {
      return t == d ? b + c : c * (-Math.pow(2, (-10 * t) / d) + 1) + b;
    },
    easeInOut: 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;
    }
  },
  Circ: {
    easeIn: function(t, b, c, d) {
      return -c * (Math.sqrt(1 - (t /= d) * t) - 1) + b;
    },
    easeOut: function(t, b, c, d) {
      return c * Math.sqrt(1 - (t = t / d - 1) * t) + b;
    },
    easeInOut: 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;
    }
  },
  Elastic: {
    easeIn: function(t, b, c, d, a, p) {
      if (t == 0) return b;
      if ((t /= d) == 1) return b + c;
      if (!p) p = d * 0.3;
      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;
    },
    easeOut: function(t, b, c, d, a, p) {
      if (t == 0) return b;
      if ((t /= d) == 1) return b + c;
      if (!p) p = d * 0.3;
      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;
    },
    easeInOut: function(t, b, c, d, a, p) {
      if (t == 0) return b;
      if ((t /= d / 2) == 2) return b + c;
      if (!p) p = d * (0.3 * 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 -0.5 * (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) * 0.5 + c + b;
    }
  },
  Back: {
    easeIn: function(t, b, c, d, s) {
      if (s == undefined) s = 1.70158;
      return c * (t /= d) * t * ((s + 1) * t - s) + b;
    },
    easeOut: 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;
    },
    easeInOut: 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: {
    easeIn: function(t, b, c, d) {
      return c - Tween.Bounce.easeOut(d - t, 0, c, d) + b;
    },
    easeOut: 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 + 0.75) + b;
      } else if (t < 2.5 / 2.75) {
        return c * (7.5625 * (t -= 2.25 / 2.75) * t + 0.9375) + b;
      } else {
        return c * (7.5625 * (t -= 2.625 / 2.75) * t + 0.984375) + b;
      }
    },
    easeInOut: function(t, b, c, d) {
      if (t < d / 2) return Tween.Bounce.easeIn(t * 2, 0, c, d) * 0.5 + b;
      else return Tween.Bounce.easeOut(t * 2 - d, 0, c, d) * 0.5 + c * 0.5 + b;
    }
  }
};

linearTween