js学习心得_一个简单的动画库封装tween.js

~function(){
  var myEffect = {
    Linear:function(t,b,c,d){
      return c*t/d+b
    },
    Quad: {//二次方的缓动（t^2）；
      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: {//三次方的缓动（t^3）
      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: {//四次方的缓动（t^4）；
      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: {//5次方的缓动（t^5）；
      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: {//正弦曲线的缓动（sin(t)）
      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: {//指数曲线的缓动（2^t）；
      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: {//圆形曲线的缓动（sqrt(1-t^2)）；
      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: {//指数衰减的正弦曲线缓动；
      easeIn: 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;
      },
      easeOut: 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);
      },
      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*(.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;
      }
    },
    Back: {//超过范围的三次方缓动（(s+1)*t^3 - s*t^2）；
      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;
      }
    },
    zfBounce: {//指数衰减的反弹缓动。
      easeIn: function(t,b,c,d){
        return c - zhufengEffect.zfBounce.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 + .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;
        }
      },
      easeInOut: function(t,b,c,d){
        if (t < d/2) return zhufengEffect.zfBounce.easeIn(t*2, 0, c, d) * .5 + b;
        else return zhufengEffect.zfBounce.easeOut(t*2-d, 0, c, d) * .5 + c*.5 + b;
      }
    }
  };
  //move:实现多方向的运动动画
  /*
    curEle:当前要运动的元素
    target:当前动画的目标位置,存储的是每一个方向的目标位置{left:xxx,top:xxx...}
    duration:当前动画的总时间
  */
  //effect支持以下的情况
  /*
    
  */
  function move(curEle,target,duration,effect,callback){
    //处理我们需要的动画效果
    var tempEffect = myEffect.Linear;
    if(typeof effect === "number"){
      switch(effect){
        case 0:
          tempEffect = myEffect.Linear;
          break;
        case 1:
          tempEffect = myEffect.Circ.easeInOut;
          break;
        case 2:
          tempEffect = myEffect.Elastic.easeOut;
          break;
        case 3:
          tempEffect = myEffect.Back.easeOut;
          break;
        case 4:
          tempEffect = myEffect.Bounce.easeOut;
          break;
        case 5:
          tempEffect = myEffect.Expo.easeIn;
      }
    }else if(effect instanceof Array){
      tempEffect = effect.length>=2 ? myEffect[effect[0]][effect[1]] : myEffect[effect[0]]
    }else if(typeof effect === "function"){
      //我们的实际意义应该是:effect是不传递值的，传递进来的函数应该是回调函数的值
      callback = effect;
    }

    //在每一次执行方法之前，首先把当前元素之前正在运行的动画结束掉
    window.clearInterval(curEle.timer);
    //根据target获取每一个方向的起始值begin和总距离change
    var begin = {},change = {};
    for(var key in target){
      if(target.hasOwnProperty(key)){
        begin[key] = utils.css(curEle,key)
        change[key] = target[key] - begin[key];

      }
    }
    //实现多方向的运动动画
    var time = 0;
    curEle.timer = window.setInterval(function(){
      time+=10;
      //到达目标：结束动画，让当前元素的样式值等于目标样式值
      if(time>=duration){
        utils.css(curEle,target);
        window.clearInterval(curEle.timer);
        //在动画结束的时候，如果用户把回调函数传递给我了，我就把用户传递的回调函数执行,不仅执行还把this的指向改为当前操作的元素

        typeof callback === "function" ? callback.call(curEle) : null;
        //或者callback && callback()
        return;
      }
      //没到达目标:分别获取每一个方向的当前位置，给当前位置设置样式即可。
      for(var key in target){
        if(target.hasOwnProperty(key)){
          var curPos = tempEffect(time,begin[key],change[key],duration);
          utils.css(curEle,key,curPos);
        }
      }
    },10)
  }

  window.myAnimate = move;
}()