Javascript 视觉 逐帧动画(修正版)

Bug修正:

1、修正重复点开始累加执行。

2、增加loop未设置初始化为循环。

3、增加设置循环时间的接口。

4、修正loop为flase无法执行第一轮的bug。

 

Code 1.1

<!DOCTYPE html>
<html>
<head>
    <meta http-equiv="content-type" content="text/html; charset=utf-8" />
    <title></title>
</head>
<body>
<div id="showImg" style="width:200px; height:300px;"></div>
<button id="start">开始</button>
<button id="stop">停止</button>
<input type="text" value="200" id="speed" />
</body>
</html>
<script type="text/javascript">

/*{
target:null,
img:url,
frames:number, 帧数
speed:500 hm,
loop:true,
width:null, //舞台尺寸
height:null
}*/
var FBFAnimation = (function(){
    function start() {
        if (this.timeLine) return;
        var speed = (this._json.speed ? this._json.speed : 500), bthis = this;
        this.timeLine = setInterval(function() {
            animation.apply(bthis);
        }, speed);
    };

    function stop() {
        if (this.timeLine) clearTimeout(this.timeLine);
        this.timeLine = null;
    };

    function setSpeed(val) {
        if (!val) return;
        this._json.speed = val;
    };

    function getPosition() {
        var x = 0, y = 0;
        if ((this.startFrames == this.endFrames) && this._json.loop) this.startFrames = 0;
        x = -(this.width * this.startFrames);

        this.startFrames++;
        return { x : x, y : y };
    };

    function animation() {
        if (!this._json.loop && this.startFrames == this.endFrames - 1) this.stop();
        var offset = getPosition.apply(this);
        this._json.target.style.backgroundPosition = ""+ offset.x +"px "+ offset.y +"px";
    };

    function init() {
        var target = this._json.target;
        this.width = 0;
        this.height = 0;
        this.startFrames = 0;
        this.endFrames = this._json.frames;
        target.style.backgroundImage = 'url(' + this._json.img + ')';
        target.style.backgroundRepeat = "no-repeat";
        target.style.backgroundPosition = "0 0";

        if (!this._json.width) this.width = parseInt(this._json.target.style.width);
        if (!this._json.height) this.height = parseInt(this._json.target.style.height);
    };

    return function(args) {
        this._json = args || {};

        if (!this._json.target) throw new Error('target is not exist!');
        if (!this._json.img) throw new Error('img not exist!');
        if (!this._json.frames) throw new Error('frames number not exist');
        if (typeof this._json.loop == "undefined") this._json.loop = true;

        init.apply(this);       //initialize

        this.start = start;     //interface
        this.stop = stop;
        this.setSpeed = setSpeed;
    };
})();

var s = new FBFAnimation({
    target : document.getElementById('showImg'),
    img : 'images/demo.jpg',
    frames : 8,
    speed : 100
});

document.getElementById('start').onclick = function() {
    s.start();
};

document.getElementById('stop').onclick = function() {
    s.stop();
};

document.getElementById('speed').onchange = function() {
    s.setSpeed(document.getElementById('speed').value);
}
</script>

 

下面是用于测试的图片

posted @ 2012-03-15 16:40  oneroundseven  阅读(3151)  评论(0)  编辑  收藏  举报