这部分对原先的缓动函数进行抽象化,并结合缓动公式进行强化。成品的效果非常惊人逆天。走过路过不要错过。
好了,打诨到此为止。普通的加速减速是难以让人满意的,为了实现弹簧等让人眼花缭乱的效果必须动用缓动公式。我见过两套缓动公式,一套是早期Robert Penner大神的缓动公式,内置到tween类中,不过现在人们越来越推荐tweenlite这个新秀了。另一套是script.aculo.us与mootools里面的,由于mootools可称之为prototype的升级版,script.aculo.us则是基于prototype,我们就把它们并称为prototype流派。与flash流派最大的不同是,它们封装得更好,并只需传入一个参数(0~1的小数),并且拥有严密的队列机制来调用各种回调函数。如在回调函数设置元素的长宽,就弄成Scale特效,利用它我们进一步制作SlideUp,SlideDown,Squish等复合特效。
我们先来看flash流派的缓动公式,它们基本都有如下四个参数。
t:timestamp,指缓动效果开始执行到当前帧开始执行时经过的时间段,单位ms
b:beginning position,起始位置
c:change,要移动的距离,就是终点位置减去起始位置。
d: duration ,缓和效果持续的时间。
我们把这四个参数传入Robert Penner大神的缓动公式,它就会计算出当前帧物体移动的位置。我们对比原来的函数来改写。
var transition = function(el){
transition.linear = function(t,b,c,d){ return c*t/d + b; };//免费提供一个缓动公式(匀速运动公式)
el.style.position = "absolute";
var options = arguments[1] || {},
begin = getCoords(el).left,//开始位置
change = parseFloat(getStyle(_("taxiway"),"width")) - parseFloat(getStyle(el,"width")),//要移动的距离
duration = options.duration || 500,//缓动效果持续时间
ease = options.ease || transition.linear,//要使用的缓动公式
end = begin + change,//结束位置
startTime = new Date().getTime();//开始执行的时间
(function(){
setTimeout(function(){
var newTime = new Date().getTime(),//当前帧开始的时间
timestamp = newTime - startTime;//逝去时间
el.style.left = ease(timestamp,begin,change,duration) + "px";//移动
if(duration <= timestamp){
el.style.left = end + "px";
}else{
setTimeout(arguments.callee,25);//每移动一次停留25毫秒
}
},25)
})()
}
接着是各种缓动公式大阅兵,共分为十一大类,除了linear。其他类又分为三种。
easeIn方法控制补间如何从开始到最高速度。
easeOut 方法控制补间减速并停在目标位置
easeInOut方法同时控制上述两者。
具体公式见下面(共31种)。
//***********@author:Robert Penner and cloudgamer*************
//http://www.cnblogs.com/cloudgamer/archive/2009/01/06/Tween.html
var Tween = {
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*.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: {
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 + .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 Tween.Bounce.easeIn(t*2, 0, c, d) * .5 + b;
else return Tween.Bounce.easeOut(t*2-d, 0, c, d) * .5 + c*.5 + b;
}
}
}
<div id="taxiway">
<div id="move" onclick="transition(this,{ease:Tween.Bounce.easeOut})"></div>
</div>
但我不喜欢flash流派的缓动公式,为了使用prototype流派的缓动公式,我进一步改进与抽象化我的缓动函数
//******************@author : 司徒正美************
var transition = function(el){
el.style.position = "absolute";
var options = arguments[1] || {},
begin = options.begin,//开始位置
change = options.change,//变化量
duration = options.duration || 500,//缓动效果持续时间
field = options.field,//必须指定,基本上对top,left,width,height这个属性进行设置
ftp = options.ftp || 50,
onStart = options.onStart || function(){},
onEnd = options.onEnd || function(){},
ease = options.ease,//要使用的缓动公式
end = begin + change,//结束位置
startTime = new Date().getTime();//开始执行的时间
onStart();
(function(){
setTimeout(function(){
var newTime = new Date().getTime(),//当前帧开始的时间
timestamp = newTime - startTime,//逝去时间
delta = ease(timestamp / duration);
el.style[field] = Math.ceil(begin + delta * change) + "px"
if(duration <= timestamp){
el.style[field] = end + "px";
onEnd();
}else{
setTimeout(arguments.callee,1000/ftp);
}
},1000/ftp)
})()
}
参数 类型 说明
el element 必需,为页面元素
begin number 必需,开始的位置
change number 必需,要移动的距离
duration number 可选,缓动效果持续时间,默认是500ms。建议取300~1000ms。
field string 必需,要发生变化的样式属性。请在top,left,bottom,right,width与height中选择。
ftp number 可选,每秒进行多少帧动画,默认50帧,保证流畅播放。一些参考资料,日本动画1秒36帧,中国卡通24帧,赛车游戏60帧。
ease function 必需,缓动公式,参数为0~1之间的数。可参考我下面给出的45条公式。
onStart function 可选,在开始时执行。
onEnd function 可选,在结束时执行。
prototype流派的缓动公式,只需一个参数(增至45种)
var tween = {
easeInQuad: function(pos){
return Math.pow(pos, 2);
},
easeOutQuad: function(pos){
return -(Math.pow((pos-1), 2) -1);
},
easeInOutQuad: function(pos){
if ((pos/=0.5) < 1) return 0.5*Math.pow(pos,2);
return -0.5 * ((pos-=2)*pos - 2);
},
easeInCubic: function(pos){
return Math.pow(pos, 3);
},
easeOutCubic: function(pos){
return (Math.pow((pos-1), 3) +1);
},
easeInOutCubic: function(pos){
if ((pos/=0.5) < 1) return 0.5*Math.pow(pos,3);
return 0.5 * (Math.pow((pos-2),3) + 2);
},
easeInQuart: function(pos){
return Math.pow(pos, 4);
},
easeOutQuart: function(pos){
return -(Math.pow((pos-1), 4) -1)
},
easeInOutQuart: function(pos){
if ((pos/=0.5) < 1) return 0.5*Math.pow(pos,4);
return -0.5 * ((pos-=2)*Math.pow(pos,3) - 2);
},
easeInQuint: function(pos){
return Math.pow(pos, 5);
},
easeOutQuint: function(pos){
return (Math.pow((pos-1), 5) +1);
},
easeInOutQuint: function(pos){
if ((pos/=0.5) < 1) return 0.5*Math.pow(pos,5);
return 0.5 * (Math.pow((pos-2),5) + 2);
},
easeInSine: function(pos){
return -Math.cos(pos * (Math.PI/2)) + 1;
},
easeOutSine: function(pos){
return Math.sin(pos * (Math.PI/2));
},
easeInOutSine: function(pos){
return (-.5 * (Math.cos(Math.PI*pos) -1));
},
easeInExpo: function(pos){
return (pos==0) ? 0 : Math.pow(2, 10 * (pos - 1));
},
easeOutExpo: function(pos){
return (pos==1) ? 1 : -Math.pow(2, -10 * pos) + 1;
},
easeInOutExpo: function(pos){
if(pos==0) return 0;
if(pos==1) return 1;
if((pos/=0.5) < 1) return 0.5 * Math.pow(2,10 * (pos-1));
return 0.5 * (-Math.pow(2, -10 * --pos) + 2);
},
easeInCirc: function(pos){
return -(Math.sqrt(1 - (pos*pos)) - 1);
},
easeOutCirc: function(pos){
return Math.sqrt(1 - Math.pow((pos-1), 2))
},
easeInOutCirc: function(pos){
if((pos/=0.5) < 1) return -0.5 * (Math.sqrt(1 - pos*pos) - 1);
return 0.5 * (Math.sqrt(1 - (pos-=2)*pos) + 1);
},
easeOutBounce: function(pos){
if ((pos) < (1/2.75)) {
return (7.5625*pos*pos);
} else if (pos < (2/2.75)) {
return (7.5625*(pos-=(1.5/2.75))*pos + .75);
} else if (pos < (2.5/2.75)) {
return (7.5625*(pos-=(2.25/2.75))*pos + .9375);
} else {
return (7.5625*(pos-=(2.625/2.75))*pos + .984375);
}
},
easeInBack: function(pos){
var s = 1.70158;
return (pos)*pos*((s+1)*pos - s);
},
easeOutBack: function(pos){
var s = 1.70158;
return (pos=pos-1)*pos*((s+1)*pos + s) + 1;
},
easeInOutBack: function(pos){
var s = 1.70158;
if((pos/=0.5) < 1) return 0.5*(pos*pos*(((s*=(1.525))+1)*pos -s));
return 0.5*((pos-=2)*pos*(((s*=(1.525))+1)*pos +s) +2);
},
elastic: function(pos) {
return -1 * Math.pow(4,-8*pos) * Math.sin((pos*6-1)*(2*Math.PI)/2) + 1;
},
swingFromTo: function(pos) {
var s = 1.70158;
return ((pos/=0.5) < 1) ? 0.5*(pos*pos*(((s*=(1.525))+1)*pos - s)) :
0.5*((pos-=2)*pos*(((s*=(1.525))+1)*pos + s) + 2);
},
swingFrom: function(pos) {
var s = 1.70158;
return pos*pos*((s+1)*pos - s);
},
swingTo: function(pos) {
var s = 1.70158;
return (pos-=1)*pos*((s+1)*pos + s) + 1;
},
bounce: function(pos) {
if (pos < (1/2.75)) {
return (7.5625*pos*pos);
} else if (pos < (2/2.75)) {
return (7.5625*(pos-=(1.5/2.75))*pos + .75);
} else if (pos < (2.5/2.75)) {
return (7.5625*(pos-=(2.25/2.75))*pos + .9375);
} else {
return (7.5625*(pos-=(2.625/2.75))*pos + .984375);
}
},
bouncePast: function(pos) {
if (pos < (1/2.75)) {
return (7.5625*pos*pos);
} else if (pos < (2/2.75)) {
return 2 - (7.5625*(pos-=(1.5/2.75))*pos + .75);
} else if (pos < (2.5/2.75)) {
return 2 - (7.5625*(pos-=(2.25/2.75))*pos + .9375);
} else {
return 2 - (7.5625*(pos-=(2.625/2.75))*pos + .984375);
}
},
easeFromTo: function(pos) {
if ((pos/=0.5) < 1) return 0.5*Math.pow(pos,4);
return -0.5 * ((pos-=2)*Math.pow(pos,3) - 2);
},
easeFrom: function(pos) {
return Math.pow(pos,4);
},
easeTo: function(pos) {
return Math.pow(pos,0.25);
},
linear: function(pos) {
return pos
},
sinusoidal: function(pos) {
return (-Math.cos(pos*Math.PI)/2) + 0.5;
},
reverse: function(pos) {
return 1 - pos;
},
mirror: function(pos, transition) {
transition = transition || tween.sinusoidal;
if(pos<0.5)
return transition(pos*2);
else
return transition(1-(pos-0.5)*2);
},
flicker: function(pos) {
var pos = pos + (Math.random()-0.5)/5;
return tween.sinusoidal(pos < 0 ? 0 : pos > 1 ? 1 : pos);
},
wobble: function(pos) {
return (-Math.cos(pos*Math.PI*(9*pos))/2) + 0.5;
},
pulse: function(pos, pulses) {
return (-Math.cos((pos*((pulses||5)-.5)*2)*Math.PI)/2) + .5;
},
blink: function(pos, blinks) {
return Math.round(pos*(blinks||5)) % 2;
},
spring: function(pos) {
return 1 - (Math.cos(pos * 4.5 * Math.PI) * Math.exp(-pos * 6));
},
none: function(pos){
return 0
},
full: function(pos){
return 1
}
}
<!doctype html>
<html dir="ltr" lang="zh-CN">
<head>
<meta charset="utf-8"/>
<meta http-equiv="X-UA-Compatible" content="IE=8">
<style type="text/css">
.taxiway{
width:800px;
height:100px;
background:#E8E8FF;
}
.move{
width:100px;
height:100px;
background:#a9ea00;
}
#panel {
float:left;
width:810px
}
#panel div{
float:left;
width:88px;
border:1px solid #333;
height:20px;
font-size:11px;
}
div.transition {
margin-top: 30px;
width: 200px;
height: 200px;
position: relative;
margin-bottom:10px;
}
div.transition div {
position: absolute;
height: 1px;
width: 1px;
background: #000;
}
div.transition span {
display: block;
position: absolute;
border-bottom: 1px solid #dadada;
font-size: 10px;
color: #888;
width: 200px;
left: 0px;
}
div.transition div#indicator {
position:absolute;
background-color:#a9ea00;
height: 200px;
top: 0px;
left: 0px;
}
div.transition div#marker {
background-color: #f00;
height: 6px;
width: 6px;
border-radius: 3px;
-webkit-border-radius: 3px;
-moz-border-radius: 3px;
left: 0px;
margin-bottom: -3px;
margin-left: -3px;
}
div.transition div#label {
background: transparent;
color: #ABD474;
font-size: 20px;
height: 20px;
width: 200px;
text-align: center;
top: 80px;
left: 0px;
z-index: -1;
}
</style>
<script type="text/javascript">
var getCoords = function(el){
var box = el.getBoundingClientRect(),
doc = el.ownerDocument,
body = doc.body,
html = doc.documentElement,
clientTop = html.clientTop || body.clientTop || 0,
clientLeft = html.clientLeft || body.clientLeft || 0,
top = box.top + (self.pageYOffset || html.scrollTop || body.scrollTop ) - clientTop,
left = box.left + (self.pageXOffset || html.scrollLeft || body.scrollLeft) - clientLeft
return { 'top': top, 'left': left };
};
var getStyle = function(el, style){
if(!+"\v1"){
style = style.replace(/\-(\w)/g, function(all, letter){
return letter.toUpperCase();
});
var value = el.currentStyle[style];
(value == "auto")&&(value = "0px" );
return value;
}else{
return document.defaultView.getComputedStyle(el, null).getPropertyValue(style)
}
}
var tween = {
easeInQuad: function(pos){
return Math.pow(pos, 2);
},
easeOutQuad: function(pos){
return -(Math.pow((pos-1), 2) -1);
},
easeInOutQuad: function(pos){
if ((pos/=0.5) < 1) return 0.5*Math.pow(pos,2);
return -0.5 * ((pos-=2)*pos - 2);
},
easeInCubic: function(pos){
return Math.pow(pos, 3);
},
easeOutCubic: function(pos){
return (Math.pow((pos-1), 3) +1);
},
easeInOutCubic: function(pos){
if ((pos/=0.5) < 1) return 0.5*Math.pow(pos,3);
return 0.5 * (Math.pow((pos-2),3) + 2);
},
easeInQuart: function(pos){
return Math.pow(pos, 4);
},
easeOutQuart: function(pos){
return -(Math.pow((pos-1), 4) -1)
},
easeInOutQuart: function(pos){
if ((pos/=0.5) < 1) return 0.5*Math.pow(pos,4);
return -0.5 * ((pos-=2)*Math.pow(pos,3) - 2);
},
easeInQuint: function(pos){
return Math.pow(pos, 5);
},
easeOutQuint: function(pos){
return (Math.pow((pos-1), 5) +1);
},
easeInOutQuint: function(pos){
if ((pos/=0.5) < 1) return 0.5*Math.pow(pos,5);
return 0.5 * (Math.pow((pos-2),5) + 2);
},
easeInSine: function(pos){
return -Math.cos(pos * (Math.PI/2)) + 1;
},
easeOutSine: function(pos){
return Math.sin(pos * (Math.PI/2));
},
easeInOutSine: function(pos){
return (-.5 * (Math.cos(Math.PI*pos) -1));
},
easeInExpo: function(pos){
return (pos==0) ? 0 : Math.pow(2, 10 * (pos - 1));
},
easeOutExpo: function(pos){
return (pos==1) ? 1 : -Math.pow(2, -10 * pos) + 1;
},
easeInOutExpo: function(pos){
if(pos==0) return 0;
if(pos==1) return 1;
if((pos/=0.5) < 1) return 0.5 * Math.pow(2,10 * (pos-1));
return 0.5 * (-Math.pow(2, -10 * --pos) + 2);
},
easeInCirc: function(pos){
return -(Math.sqrt(1 - (pos*pos)) - 1);
},
easeOutCirc: function(pos){
return Math.sqrt(1 - Math.pow((pos-1), 2))
},
easeInOutCirc: function(pos){
if((pos/=0.5) < 1) return -0.5 * (Math.sqrt(1 - pos*pos) - 1);
return 0.5 * (Math.sqrt(1 - (pos-=2)*pos) + 1);
},
easeOutBounce: function(pos){
if ((pos) < (1/2.75)) {
return (7.5625*pos*pos);
} else if (pos < (2/2.75)) {
return (7.5625*(pos-=(1.5/2.75))*pos + .75);
} else if (pos < (2.5/2.75)) {
return (7.5625*(pos-=(2.25/2.75))*pos + .9375);
} else {
return (7.5625*(pos-=(2.625/2.75))*pos + .984375);
}
},
easeInBack: function(pos){
var s = 1.70158;
return (pos)*pos*((s+1)*pos - s);
},
easeOutBack: function(pos){
var s = 1.70158;
return (pos=pos-1)*pos*((s+1)*pos + s) + 1;
},
easeInOutBack: function(pos){
var s = 1.70158;
if((pos/=0.5) < 1) return 0.5*(pos*pos*(((s*=(1.525))+1)*pos -s));
return 0.5*((pos-=2)*pos*(((s*=(1.525))+1)*pos +s) +2);
},
elastic: function(pos) {
return -1 * Math.pow(4,-8*pos) * Math.sin((pos*6-1)*(2*Math.PI)/2) + 1;
},
swingFromTo: function(pos) {
var s = 1.70158;
return ((pos/=0.5) < 1) ? 0.5*(pos*pos*(((s*=(1.525))+1)*pos - s)) :
0.5*((pos-=2)*pos*(((s*=(1.525))+1)*pos + s) + 2);
},
swingFrom: function(pos) {
var s = 1.70158;
return pos*pos*((s+1)*pos - s);
},
swingTo: function(pos) {
var s = 1.70158;
return (pos-=1)*pos*((s+1)*pos + s) + 1;
},
bounce: function(pos) {
if (pos < (1/2.75)) {
return (7.5625*pos*pos);
} else if (pos < (2/2.75)) {
return (7.5625*(pos-=(1.5/2.75))*pos + .75);
} else if (pos < (2.5/2.75)) {
return (7.5625*(pos-=(2.25/2.75))*pos + .9375);
} else {
return (7.5625*(pos-=(2.625/2.75))*pos + .984375);
}
},
bouncePast: function(pos) {
if (pos < (1/2.75)) {
return (7.5625*pos*pos);
} else if (pos < (2/2.75)) {
return 2 - (7.5625*(pos-=(1.5/2.75))*pos + .75);
} else if (pos < (2.5/2.75)) {
return 2 - (7.5625*(pos-=(2.25/2.75))*pos + .9375);
} else {
return 2 - (7.5625*(pos-=(2.625/2.75))*pos + .984375);
}
},
easeFromTo: function(pos) {
if ((pos/=0.5) < 1) return 0.5*Math.pow(pos,4);
return -0.5 * ((pos-=2)*Math.pow(pos,3) - 2);
},
easeFrom: function(pos) {
return Math.pow(pos,4);
},
easeTo: function(pos) {
return Math.pow(pos,0.25);
},
linear: function(pos) {
return pos
},
sinusoidal: function(pos) {
return (-Math.cos(pos*Math.PI)/2) + 0.5;
},
reverse: function(pos) {
return 1 - pos;
},
mirror: function(pos, transition) {
transition = transition || tween.sinusoidal;
if(pos<0.5)
return transition(pos*2);
else
return transition(1-(pos-0.5)*2);
},
flicker: function(pos) {
var pos = pos + (Math.random()-0.5)/5;
return tween.sinusoidal(pos < 0 ? 0 : pos > 1 ? 1 : pos);
},
wobble: function(pos) {
return (-Math.cos(pos*Math.PI*(9*pos))/2) + 0.5;
},
pulse: function(pos, pulses) {
return (-Math.cos((pos*((pulses||5)-.5)*2)*Math.PI)/2) + .5;
},
blink: function(pos, blinks) {
return Math.round(pos*(blinks||5)) % 2;
},
spring: function(pos) {
return 1 - (Math.cos(pos * 4.5 * Math.PI) * Math.exp(-pos * 6));
},
none: function(pos){
return 0
},
full: function(pos){
return 1
}
}
var _ = function(id){
return document.getElementById(id);
}
var transition = function(el){
el.style.position = "absolute";
var options = arguments[1] || {},
begin = options.begin,//开始位置
change = options.change,//变化量
duration = options.duration || 500,//缓动效果持续时间
field = options.field,//必须指定,基本上对top,left,width,height这个属性进行设置
ftp = options.ftp || 50,
onEnd = options.onEnd || function(){},
ease = options.ease,//要使用的缓动公式
end = begin + change,//结束位置
startTime = new Date().getTime();//开始执行的时间
(function(){
setTimeout(function(){
var newTime = new Date().getTime(),//当前帧开始的时间
timestamp = newTime - startTime,//逝去时间
delta = ease(timestamp / duration);
el.style[field] = Math.ceil(begin + delta * change) + "px"
if(duration <= timestamp){
el.style[field] = end + "px";
onEnd();
}else{
setTimeout(arguments.callee,1000/ftp);
}
},1000/ftp)
})()
}
if (typeof Array.prototype['max'] == 'undefined') {
Array.prototype.map = function(fn, thisObj) {
var scope = thisObj || window;
var a = [];
for ( var i=0, j=this.length; i < j; ++i ) {
a.push(fn.call(scope, this[i], i, this));
}
return a;
};
Array.prototype.max = function(){
return Math.max.apply({},this)
}
Array.prototype.min = function(){
return Math.min.apply({},this)
}
}
var range = function(start,end){
var _range = []
for(var i = start,l=end-start;i<l;i++){
_range.push(i)
}
return _range
}
var draw = function(ease){
var demo = _("transition");
demo.innerHTML = "";//还原!
//***********绘制控制台********************
var values = range(0,200).map(function(v){
return tween[ease](v/200) * 200;
}),
max = Math.max(200, values.max()),
min = Math.min(0, values.min());
if (min==max) {
min = 0;
max = 200;
}
var factor = 200/(max-min),
grid = '<span style="bottom:'+Math.round((0-min)*factor)+'px">0</span>'+
'<span style="bottom:'+Math.round((200-min)*factor)+'px">1</span>',
graph = range(0,200).map(function(v){
return '<div style="left:'+v+'px;bottom:'+Math.round((values[v]-min)*factor)+'px;height:1px"></div>';
}).join('') + '<div id="indicator" style="display:none">'
+'</div><div id="marker" style="display:none"></div><div id="label"></div>';
demo.innerHTML = grid + graph;
var indicator = _("indicator"),
marker = _("marker"),
label = _("label"),
demoTransition = function(pos){
var value = tween[ease](pos);
indicator.style.display = "block";
marker.style.display = "block";
marker.style.left = Math.round(pos*200)+'px';
marker.style.bottom = Math.round((value*200-min)*factor)+'px';
label.innerHTML = Math.round(pos*200)+'px';
return value;
}
transition(i