jQuery动画的实现

没有引入deferred机制，其余流程都有了

////////////
//创建动画缓动对象 //
////////////
function Tween(value, prop, animation) {
    this.elem    = animation.elem;
    this.prop    = prop;
    this.easing  = "swing"; //动画缓动算法
    this.options = animation.options;
    //获取初始值
    this.start   = this.now = this.get();
    //动画最终值
    this.end     = value;
    //单位
    this.unit    = "px"
}

function getStyles(elem) {
    return elem.ownerDocument.defaultView.getComputedStyle(elem, null);
};

function swing(p) {
    return 0.5 - Math.cos(p * Math.PI) / 2;
}

Tween.prototype = {
    //获取元素的当前属性
    get: function() {
        var computed = getStyles(this.elem);
        var ret = computed.getPropertyValue(this.prop) || computed[this.prop];
        return parseFloat(ret);
    },
    //运行动画
    run:function(percent){
        var eased
        //根据缓动算法改变percent
        this.pos = eased = swing(percent);
        //获取具体的改变坐标值
        this.now = (this.end - this.start) * eased + this.start;
        //最终改变坐标
        this.elem.style[this.prop] = this.now + "px";
        return this;
    }
}


////////
//动画类 //
////////
function Animation(elem, properties, options){
    //动画对象
    var animation = {
        elem            : elem,
        props           : properties,
        originalOptions : options,
        options         : options,
        startTime       : Animation.fxNow || createFxNow(),//动画开始时间
        tweens          : [] //存放每个属性的缓动对象，用于动画
    }

    //生成属性对应的动画算法对象
    for (var k in properties) {
        // tweens保存每一个属性对应的缓动控制对象
        animation.tweens.push( new Tween(properties[k], k, animation) )
    }

    //动画状态
    var stopped;
    //动画的定时器调用包装器
    var tick = function() {
        if (stopped) {
            return false;
        }
        //动画时间算法
        var currentTime = Animation.fxNow || createFxNow
            //运动时间递减
            remaining = Math.max(0, animation.startTime + animation.options.duration - currentTime),
            temp = remaining / animation.options.duration || 0,
            percent = 1 - temp;

        var index = 0,
            length = animation.tweens.length;

        //执行动画改变
        for (; index < length; index++) {
            //percent改变值
            animation.tweens[index].run(percent);
        }

        //是否继续，还是停止
        if (percent <= 1 && length) {
            return remaining;
        } else {
            //停止
            return false;
        }

    }
    tick.elem = elem;
    tick.anim = animation

    Animation.fx.timer(tick)
}    

//创建开始时间
function createFxNow() {
    setTimeout(function() {
        Animation.fxNow = undefined;
    });
    return (Animation.fxNow = Date.now());
}


//用于定时器调用
Animation.timers =[]

Animation.fx = {
    //开始动画队列
    timer: function(timer) {
        Animation.timers.push(timer);
        if (timer()) {
            //开始执行动画
            Animation.fx.start();
        } else {
            Animation.timers.pop();
        }
    },
    //开始循环
    start: function() {
        if (!Animation.timerId) {
            Animation.timerId = setInterval(Animation.fx.tick, 13);
        }
    },
    //停止循环
    stop:function(){
        clearInterval(Animation.timerId);
        Animation.timerId = null;
    },
    //循环的的检测
    tick: function() {
        var timer,
            i = 0,
            timers = Animation.timers;

        Animation.fxNow = Date.now();

        for (; i < timers.length; i++) {
            timer = timers[i];
            if (!timer() && timers[i] === timer) {
                //如果完成了就删除这个动画
                timers.splice(i--, 1);
            }
        }

        if (!timers.length) {
            Animation.fx.stop();
        }
        Animation.fxNow = undefined;
    }
}

测试：

<!doctype html>

<button id="one">jQuery动画的模拟实现:left:50</button> <button id="two">jQuery动画的模拟实现:left:500</button><ul id="book" style="background:red;opacity:1;position: relative; left: 300px;width:200px;height:100px;display:inline;" data-mce-style="background: red; opacity: 1; position: relative; left: 300px; width: 200px; height: 100px; display: inline;"></ul><script type="mce-text/javascript"> var book = document.getElementById('book'); var $book = $('#book'); var i = 10 while(i){ $book.append("<li>11</li>") i--; } //////////// //创建动画缓动对象 // //////////// function Tween(value, prop, animation) { this.elem = animation.elem; this.prop = prop; this.easing = "swing"; //动画缓动算法 this.options = animation.options; //获取初始值 this.start = this.now = this.get(); //动画最终值 this.end = value; //单位 this.unit = "px" } function getStyles(elem) { return elem.ownerDocument.defaultView.getComputedStyle(elem, null); }; function swing(p) { return 0.5 - Math.cos(p * Math.PI) / 2; } Tween.prototype = { //获取元素的当前属性 get: function() { var computed = getStyles(this.elem); var ret = computed.getPropertyValue(this.prop) || computed[this.prop]; return parseFloat(ret); }, //运行动画 run:function(percent){ var eased //根据缓动算法改变percent this.pos = eased = swing(percent); //获取具体的改变坐标值 this.now = (this.end - this.start) * eased + this.start; //最终改变坐标 this.elem.style[this.prop] = this.now + "px"; return this; } } //////// //动画类 // //////// function Animation(elem, properties, options){ //动画对象 var animation = { elem : elem, props : properties, originalOptions : options, options : options, startTime : Animation.fxNow || createFxNow(),//动画开始时间 tweens : [] //存放每个属性的缓动对象，用于动画 } //生成属性对应的动画算法对象 for (var k in properties) { // tweens保存每一个属性对应的缓动控制对象 animation.tweens.push( new Tween(properties[k], k, animation) ) } //动画状态 var stopped; //动画的定时器调用包装器 var tick = function() { if (stopped) { return false; } //动画时间算法 var currentTime = Animation.fxNow || createFxNow //运动时间递减 remaining = Math.max(0, animation.startTime + animation.options.duration - currentTime), temp = remaining / animation.options.duration || 0, percent = 1 - temp; var index = 0, length = animation.tweens.length; //执行动画改变 for (; index < length; index++) { //percent改变值 animation.tweens[index].run(percent); } //是否继续，还是停止 if (percent <= 1 && length) { return remaining; } else { //停止 return false; } } tick.elem = elem; tick.anim = animation Animation.fx.timer(tick) } //创建开始时间 function createFxNow() { setTimeout(function() { Animation.fxNow = undefined; }); return (Animation.fxNow = Date.now()); } //用于定时器调用 Animation.timers =[] Animation.fx = { //开始动画队列 timer: function(timer) { Animation.timers.push(timer); if (timer()) { //开始执行动画 Animation.fx.start(); } else { Animation.timers.pop(); } }, //开始循环 start: function() { if (!Animation.timerId) { Animation.timerId = setInterval(Animation.fx.tick, 13); } }, //停止循环 stop:function(){ clearInterval(Animation.timerId); Animation.timerId = null; }, //循环的的检测 tick: function() { var timer, i = 0, timers = Animation.timers; Animation.fxNow = Date.now(); for (; i < timers.length; i++) { timer = timers[i]; if (!timer() && timers[i] === timer) { //如果完成了就删除这个动画 timers.splice(i--, 1); } } if (!timers.length) { Animation.fx.stop(); } Animation.fxNow = undefined; } } $("#one").click(function(){ Animation(book, { left: '50' }, { duration: 2000 }) }); $("#two").click(function() { Animation(book, { left: '500' }, { duration: 2000 }) }); </script>

posted on 2015-02-11 10:27 【艾伦】阅读(5181) 评论(3) 编辑收藏举报

jQuery动画的实现

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