Tween的主页在这里:http://createjs.com/tweenjs , 这里边还有挺多开源项目的;
Tween公式 4个参数
t:current time(当前时间)
b:beginning value(初始值)
c: change in value(变化量)
d:duration(持续时间) return (目标点)
var Tween = { linear: function (t, b, c, d){ //匀速 return c*t/d + b; }, easeIn: function(t, b, c, d){ //加速曲线 return c*(t/=d)*t + b; }, easeOut: function(t, b, c, d){ //减速曲线 return -c *(t/=d)*(t-2) + b; }, easeBoth: function(t, b, c, d){ //加速减速曲线 if ((t/=d/2) < 1) { return c/2*t*t + b; } return -c/2 * ((--t)*(t-2) - 1) + b; }, easeInStrong: function(t, b, c, d){ //加加速曲线 return c*(t/=d)*t*t*t + b; }, easeOutStrong: function(t, b, c, d){ //减减速曲线 return -c * ((t=t/d-1)*t*t*t - 1) + b; }, easeBothStrong: function(t, b, c, d){ //加加速减减速曲线 if ((t/=d/2) < 1) { return c/2*t*t*t*t + b; } return -c/2 * ((t-=2)*t*t*t - 2) + b; }, elasticIn: function(t, b, c, d, a, p){ //正弦衰减曲线(弹动渐入) 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; }, elasticOut: function(t, b, c, d, a, p){ //正弦增强曲线(弹动渐出) 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; }, elasticBoth: 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; }, backIn: function(t, b, c, d, s){ //回退加速(回退渐入) if (typeof s == 'undefined') { s = 1.70158; } return c*(t/=d)*t*((s+1)*t - s) + b; }, backOut: function(t, b, c, d, s){ if (typeof s == 'undefined') { s = 3.70158; //回缩的距离 } return c*((t=t/d-1)*t*((s+1)*t + s) + 1) + b; }, backBoth: function(t, b, c, d, s){ if (typeof 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; }, bounceIn: function(t, b, c, d){ //弹球减振(弹球渐出) return c - Tween['bounceOut'](d-t, 0, c, d) + b; }, bounceOut: 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; } return c*(7.5625*(t-=(2.625/2.75))*t + 0.984375) + b; }, bounceBoth: function(t, b, c, d){ if (t < d/2) { return Tween['bounceIn'](t*2, 0, c, d) * 0.5 + b; } return Tween['bounceOut'](t*2-d, 0, c, d) * 0.5 + c*0.5 + b; } }
在平常使用jQuey或者写运动效果都是使用根据目标终点运动的库, 如果要用到和时间有关的运动咋办, 那么就可以根据miaov的完美运动框架改一改, 把计算速度的过程,使用Tween的方法替代:
<html> <head> <title></title>
//记得引用这个JS <script src="tween.js"></script> <style type="text/css"> div{ 100px; height:100px; position:absolute; left:10px; top:100px; background:#f00; } div:hover{ 400px; } </style> </head> <body> <div id="div"> </div> <script> window.onload = function() { move(eDiv, "left", "300",1000, "linear") } var getStyle = function(el, prop) { return window.getComputedStyle(el)[prop]; } var move = function(el, prop, dest, duration , fx) { var start = new Date().getTime(); var startValue = parseFloat(getStyle(el, prop)); var changeValue = dest - startValue; var timer = setInterval(function() { //1:当前时间 new Date - start; //2:初始值; //3:变化量; //4:持续时间 duration; var value = Tween[fx](new Date-start, startValue, changeValue, duration); if(prop === "opacity") { el.style[prop] = value; }else{ el.style[prop] = value + "px"; } if(new Date()>=duration+start) { clearInterval(timer); if(prop === "opacity") { el.style[prop] = dest; }else{ el.style[prop] = dest + "px"; } } },30); }; var eDiv = document.getElementById("div"); </script> </body> </html>