新闻展示,滚动新闻
程序说明
原理就是通过不断设置滑动对象的left(水平切换)和top(垂直切换)来实现图片切换的动态效果。
首先需要一个容器,程序会自动设置容器overflow为hidden,如果不是相对或绝对定位会同时设置position为relative,
滑动对象会设置为绝对定位:
- var p = CurrentStyle(this._container).position;
- p == "relative" || p == "absolute" || (this._container.style.position = "relative");
- this._container.style.overflow = "hidden";
- this._slider.style.position = "absolute";
如果没有设置Change切换参数属性,会自动根据滑动对象获取:
- this.Change = this.options.Change ? this.options.Change :
- this._slider[bVertical ? "offsetHeight" : "offsetWidth"] / this._count;
执行Run方法就会开始进入切换,其中有一个可选参数用来重新设置要切换的图片索引:
- index == undefined && (index = this.Index);
- index < 0 && (index = this._count - 1) || index >= this._count && (index = 0);
之后就到设置使用tween缓动时需要的参数了,
包括_target(目标值)、_t(时间)、_b(初始值)和_c(变化量):
- this._target = -Math.abs(this.Change) * (this.Index = index);
- this._t = 0;
- this._b = parseInt(CurrentStyle(this._slider)[this.options.Vertical ? "top" : "left"]);
- this._c = this._target - this._b;
还有Duration(持续时间)是自定义属性。
参数设置好后就执行Move程序开始移动了。
里面很简单,首先判断_c是否有值(等于0表示不需要移动)和_t是否到达Duration,
未满足条件就继续移动,否则直接移动到目标值并进行下一次切换:
- if (this._c && this._t < this.Duration) {
- this.MoveTo(Math.round(this.Tween(this._t++, this._b, this._c, this.Duration)));
- this._timer = setTimeout(Bind(this, this.Move), this.Time);
- }else{
- this.MoveTo(this._target);
- this.Auto && (this._timer = setTimeout(Bind(this, this.Next), this.Pause));
- }
使用说明
实例化需要3个参数,分别是容器对象,滑动对象和切换数量,之后可以直接执行Run方法运行:
- new SlideTrans("idContainer", "idSlider", 3).Run();
还有以下可选属性:
Vertical: true,//是否垂直方向(方向不能改)
Auto: true,//是否自动
Change: 0,//改变量
Duration: 50,//滑动持续时间
Time: 10,//滑动延时
Pause: 2000,//停顿时间(Auto为true时有效)
onStart: function(){},//开始转换时执行
onFinish: function(){},//完成转换时执行
Tween: Tween.Quart.easeOut//tween算子
其中Vertical初始化后就不能修改,Tween算子可参照这里的缓动效果选择(实例中选了其中3个)。
还有提供了以下方法:
Next: 切换下一个
Previous: 切换上一个
Stop: 停止自动切换
还有上面说到的Run
完整程序代码:
- <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
- <html xmlns="http://www.w3.org/1999/xhtml">
- <head>
- <meta http-equiv="Content-Type" content="text/html; charset=gb2312" />
- <title>JavaScript 图片滑动切换效果</title>
- <script type="text/javascript">
- var $ = function (id) {
- return "string" == typeof id ? document.getElementById(id) : id;
- };
-
- var Extend = function(destination, source) {
- for (var property in source) {
- destination[property] = source[property];
- }
- return destination;
- }
-
- var CurrentStyle = function(element){
- return element.currentStyle || document.defaultView.getComputedStyle(element, null);
- }
-
- var Bind = function(object, fun) {
- var args = Array.prototype.slice.call(arguments).slice(2);
- return function() {
- return fun.apply(object, args.concat(Array.prototype.slice.call(arguments)));
- }
- }
-
- var Tween = {
- Quart: {
- easeOut: function(t,b,c,d){
- return -c * ((t=t/d-1)*t*t*t - 1) + b;
- }
- },
- Back: {
- 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;
- }
- },
- Bounce: {
- 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;
- }
- }
- }
- }
-
-
-
- var SlideTrans = function(container, slider, count, options) {
- this._slider = $(slider);
- this._container = $(container);
- this._timer = null;
- this._count = Math.abs(count);
- this._target = 0;
- this._t = this._b = this._c = 0;
-
- this.Index = 0;
-
- this.SetOptions(options);
-
- this.Auto = !!this.options.Auto;
- this.Duration = Math.abs(this.options.Duration);
- this.Time = Math.abs(this.options.Time);
- this.Pause = Math.abs(this.options.Pause);
- this.Tween = this.options.Tween;
- this.onStart = this.options.onStart;
- this.onFinish = this.options.onFinish;
-
- var bVertical = !!this.options.Vertical;
- this._css = bVertical ? "top" : "left";
-
-
- var p = CurrentStyle(this._container).position;
- p == "relative" || p == "absolute" || (this._container.style.position = "relative");
- this._container.style.overflow = "hidden";
- this._slider.style.position = "absolute";
-
- this.Change = this.options.Change ? this.options.Change :
- this._slider[bVertical ? "offsetHeight" : "offsetWidth"] / this._count;
- };
- SlideTrans.prototype = {
-
- SetOptions: function(options) {
- this.options = {
- Vertical: true,
- Auto: true,
- Change: 0,
- Duration: 50,
- Time: 10,
- Pause: 2000,
- onStart: function(){},
- onFinish: function(){},
- Tween: Tween.Quart.easeOut
- };
- Extend(this.options, options || {});
- },
-
- Run: function(index) {
-
- index == undefined && (index = this.Index);
- index < 0 && (index = this._count - 1) || index >= this._count && (index = 0);
-
- this._target = -Math.abs(this.Change) * (this.Index = index);
- this._t = 0;
- this._b = parseInt(CurrentStyle(this._slider)[this.options.Vertical ? "top" : "left"]);
- this._c = this._target - this._b;
-
- this.onStart();
- this.Move();
- },
-
- Move: function() {
- clearTimeout(this._timer);
-
- if (this._c && this._t < this.Duration) {
- this.MoveTo(Math.round(this.Tween(this._t++, this._b, this._c, this.Duration)));
- this._timer = setTimeout(Bind(this, this.Move), this.Time);
- }else{
- this.MoveTo(this._target);
- this.Auto && (this._timer = setTimeout(Bind(this, this.Next), this.Pause));
- }
- },
-
- MoveTo: function(i) {
- this._slider.style[this._css] = i + "px";
- },
-
- Next: function() {
- this.Run(++this.Index);
- },
-
- Previous: function() {
- this.Run(--this.Index);
- },
-
- Stop: function() {
- clearTimeout(this._timer); this.MoveTo(this._target);
- }
- };
- </script>
- </head>
- <body>
- <style type="text/css">
- .container, .container img{width:280px; height:200px;}
- .container{border:1px solid #333;}
- .container img{border:0;}
- </style>
- <div class="container" id="idContainer">
- <table id="idSlider" border="0" cellpadding="0" cellspacing="0">
- <tr>
- <td><a href="http://www.cnblogs.com/cloudgamer/archive/2009/01/06/Tween.html"><img src="http://images.cnblogs.com/cnblogs_com/cloudgamer/143727/r_rt_1.jpg"/></a></td>
- </tr>
- <tr>
- <td><a href="http://www.cnblogs.com/cloudgamer/archive/2008/07/21/ImgCropper.html"><img src="http://images.cnblogs.com/cnblogs_com/cloudgamer/143727/r_rt_5.jpg"/></a></td>
- </tr>
- <tr>
- <td><a href="http://www.cnblogs.com/cloudgamer/archive/2008/11/17/Drag.html"><img src="http://images.cnblogs.com/cnblogs_com/cloudgamer/143727/r_rt_3.jpg"/></a></td>
- </tr>
- </table>
- </div>
- <br />
- <br />
- <style type="text/css">
- .num{ position:absolute; right:5px; bottom:5px;}
- .num li{
- float: left;
- list-style:none;
- color: #fff;
- text-align: center;
- line-height: 16px;
- width: 16px;
- height: 16px;
- font-family: Arial;
- font-size: 12px;
- cursor: pointer;
- margin: 1px;
- border: 1px solid #707070;
- background-color: #060a0b;
- }
- .num li.on{
- line-height: 18px;
- width: 18px;
- height: 18px;
- font-size: 14px;
- border: 0;
- background-color: #ce0609;
- font-weight: bold;
- }
- </style>
- <div class="container" id="idContainer2">
- <table id="idSlider2" border="0" cellpadding="0" cellspacing="0">
- <tr>
- <td><a href="http://www.cnblogs.com/cloudgamer/archive/2009/03/11/color.html"><img src="http://images.cnblogs.com/cnblogs_com/cloudgamer/143727/r_4.jpg"/></a></td>
- <td><a href="http://www.cnblogs.com/cloudgamer/archive/2008/12/24/Slider.html"><img src="http://images.cnblogs.com/cnblogs_com/cloudgamer/143727/r_3.jpg"/></a></td>
- <td><a href="http://www.cnblogs.com/cloudgamer/archive/2008/12/03/Resize.html"><img src="http://images.cnblogs.com/cnblogs_com/cloudgamer/143727/r_rt_2.jpg"/></a></td>
- </tr>
- </table>
- <ul class="num" id="idNum">
- </ul>
- </div>
- <br />
- <div>
- <input id="idAuto" type="button" value="停止" />
- <input id="idPre" type="button" value="<<" />
- <input id="idNext" type="button" value=">>" />
- <select id="idTween">
- <option value="0">默认缓动</option>
- <option value="1">方式1</option>
- <option value="2">方式2</option>
- </select>
- </div>
- <script>
-
- new SlideTrans("idContainer", "idSlider", 3).Run();
-
-
-
- var forEach = function(array, callback, thisObject){
- if(array.forEach){
- array.forEach(callback, thisObject);
- }else{
- for (var i = 0, len = array.length; i < len; i++) { callback.call(thisObject, array[i], i, array); }
- }
- }
-
- var st = new SlideTrans("idContainer2", "idSlider2", 3, { Vertical: false });
-
- var nums = [];
-
- for(var i = 0, n = st._count - 1; i <= n;){
- (nums[i] = $("idNum").appendChild(document.createElement("li"))).innerHTML = ++i;
- }
-
- forEach(nums, function(o, i){
- o.onmouseover = function(){ o.className = "on"; st.Auto = false; st.Run(i); }
- o.onmouseout = function(){ o.className = ""; st.Auto = true; st.Run(); }
- })
-
-
- st.onStart = function(){
- forEach(nums, function(o, i){ o.className = st.Index == i ? "on" : ""; })
- }
-
- $("idAuto").onclick = function(){
- if(st.Auto){
- st.Auto = false; st.Stop(); this.value = "自动";
- }else{
- st.Auto = true; st.Run(); this.value = "停止";
- }
- }
- $("idNext").onclick = function(){ st.Next(); }
- $("idPre").onclick = function(){ st.Previous(); }
-
- $("idTween").onchange = function(){
- switch (parseInt(this.value)){
- case 2 :
- st.Tween = Tween.Bounce.easeOut; break;
- case 1 :
- st.Tween = Tween.Back.easeOut; break;
- default :
- st.Tween = Tween.Quart.easeOut;
- }
- }
-
-
- st.Run();
- </script>
- </body>
- </html>