JavaScript simple easing plug-in (source code packaging)_javascript skills

The requirements are as follows:
Can start, pause (both linear and non-linear tween are supported), continue, end
Support multiple styles in parallel
It is best not to depend on a certain framework to run
The larger the file size Small is better
He searched for some existing plug-ins or libraries, but few of them were satisfactory or relatively balanced. Under this requirement, I wrote a relatively simple animation component, which basically met this requirement. First code
Online demo: http://demo.jb51.net/js/2012/animate/
Package download: animate_jquery.rar
html Part:

Copy code The code is as follows:

< ;html>

auto start,pasue,then resume

animate part:

Copy code The code is as follows:

function animate(options){
this.from = options.from;//if Without from, calculate from
this.to = options.to || {};
this.onStart = options.onStart || empty;//The following are some callback functions, the event mechanism is not used
this.onStop = options.onStop || empty;
this.onAnimate = options.onAnimate || empty;
this.onContinue = options.onContinue || empty;
this.onPause = options .onPause || empty;
var element = options.element;
var duration = options.duration || 300;//The total duration of the change, the unit is ms
var pending = false;//Yes It has not been paused, but if it has not started yet, the value is also true
var timer = null;
var mixin = options.mix;
var defaultState = this.from || getState(element, this .to);//Original data
var thiz = this;
//Get the initial style
function getState(ele, targetStyles){
var obj = {};
var i = 0;
for (var p in targetStyles)
{
i ;
obj[p] = parseFloat(mixin.getStyle(ele, p));
}
if(i == 0){
return null;
}
return obj;
}
function empty(){}
function animate(from, to, elapse) {
var startTime = (new Date).getTime() (elapse ? - elapse : 0);//If there is a third parameter, which proves that it starts from a pause, then set startTime to the current time minus The elapsed time in the tentative time. If there are only two parameters, then the elapsed time is 0
timer = setInterval(function(){
var endTime = (new Date).getTime();
if( endTime - startTime < duration){
thiz.onAnimate();
currentElapse = endTime - startTime;
for(var p in from){
if(from.hasOwnProperty(p)){
var currentPropertyStyle = mixin.compute(currentElapse, from[p], to[p]-from[p], duration);
mixin.setStyle(element, p, currentPropertyStyle);
}
}
}
else{
thiz.stop(thiz.to);
}
}, 16);
}
this.start = function(){
if(pending){
this.resume();
}
else{
this.onStart();
animate(defaultState, this.to);
}
}
this.stop = function(){
clearInterval(timer);
var styles = this.to;
for(var p in styles){
if( styles.hasOwnProperty(p)){
mixin.setStyle(element, p, styles[p]);
}
}
this.onStop();
}
this .pause = function(){
clearInterval(timer);
pending = true;
this.onPause();
}
this.resume = function(){
pending = false;
this.onContinue();
animate(defaultState, this.to, currentElapse);
}
}

使用部分：

复制代码 代码如下:

var mixinT = {
getStyle:baidu.dom.getStyle,
setStyle:baidu.dom.setStyle,
compute:function(t, b, c, d){
//return t*c/d b;
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;
}
};
var mixinJQ = {
getStyle:function(ele, styleName){
return $(ele).css(styleName);
},
setStyle:function(ele, styleName, styleValue){
$(ele).css(styleName, styleValue);
},
compute:function(t, b, c, d){
return b t*c/d;
}
};
var an = new animate({
element:document.getElementById('anim'),
//from:{'width':100, 'height':100, left:0, top:30},
to:{left:500},
mix:mixinT,
duration:2000
});
if(/demo=1/.test(location.search)){
var demolink = baidu.g('demolink');
demolink.href= 'animate.html';
demolink.innerHTML = 'back';
an.start();
setTimeout(function(){
an.pause();
resume();
}, 1200);
function resume(){
setTimeout(function(){an.resume()}, 1000);
}
}

上面是一个完整demo的代码。做几点说明：
代码尺寸足够小了，一共才100行，gzip后连1k都不到。
满足了可以start、pause、resume、stop的需求，赠送了几个回调函数:D。
可以支持多个样式一起变化。
采用了一个mixin变量，传进来三个函数需要在执行动画时的操作，getStyle、setStyle、compute，我感觉这三个确实和用户的选择有关系，前两个可能和框架有关，第三个和用户采用的变化计算方式有关，之所以传进去四个参数，主要是和主流的tween类能适应起来，可以参考http://www.robertpenner.com/easing/和http://www.actionscript.org/resources/articles/170/1/Flash-MX-2004-Undocumented-TweenEasing-Classes-Documented/Page1.html。我给的例子用了tangram和jquery俩类库，分别对应了两个mixin对象，做一下简单的适配，就能用了。
一些“私有”变量和函数放闭包里了，这样初始化一个animate的时候，对象是干净的，但是缺点就是占用内存多了，每个实例都维护自己的方法。
使用的时候，可以不提供options.from，函数会根据额options.to来计算from中对应样式的值，这很大程度上依赖于mixin提供的方法够不够强大，所以这一块还是有bug 的，不过，80%的功能够用了。麻雀虽小，五脏俱全了。