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JavaScript 颜色梯度和渐变效果

<!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 颜色梯度和渐变效果</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 Map = function(array, callback, thisObject){
 if(array.map){
  return array.map(callback, thisObject);
 }else{
  var res = [];
  for (var i = 0, len = array.length; i < len; i++) { res.push(callback.call(thisObject, array[i], i, array)); }
  return res;
 }
}


var ColorGrads = function(options){
 this.SetOptions(options);
 this.StartColor = this.options.StartColor;
 this.EndColor = this.options.EndColor;
 this.Step = Math.abs(this.options.Step);
};
ColorGrads.prototype = {
  //设置默认属性
  SetOptions: function(options) {
    this.options = {//默认值
  StartColor: "#fff",//开始颜色
  EndColor: "#000",//结束颜色
  Step:  20//渐变级数
    };
    Extend(this.options, options || {});
  },
  //获取渐变颜色集合
  Create: function() {
 var colors = [],
  startColor = this.GetColor(this.StartColor),
  endColor = this.GetColor(this.EndColor),
  stepR = (endColor[0] - startColor[0]) / this.Step,
  stepG = (endColor[1] - startColor[1]) / this.Step,
  stepB = (endColor[2] - startColor[2]) / this.Step;
 //生成颜色集合
 for(var i = 0, n = this.Step, r = startColor[0], g = startColor[1], b = startColor[2]; i < n; i++){
  colors.push([r, g, b]); r += stepR; g += stepG; b += stepB;
 }
 colors.push(endColor);
 //修正颜色值
 return Map(colors, function(x){ return Map(x, function(x){
  return Math.min(Math.max(0, Math.floor(x)), 255);
 });});
  },
  //获取颜色数据
  GetColor: function(color) {
 if(/^#[0-9a-f]{6}$/i.test(color))
 {//#rrggbb
  return Map([color.substr(1, 2), color.substr(3, 2), color.substr(5, 2)],
   function(x){ return parseInt(x, 16); }
  )
 }
 else if(/^#[0-9a-f]{3}$/i.test(color))
 {//#rgb
  return Map([color.substr(1, 1), color.substr(2, 1), color.substr(3, 1)],
   function(x){ return parseInt(x + x, 16); }
  )
 }
 else if(/^rgb(.*)$/i.test(color))
 {//rgb(n,n,n) or rgb(n%,n%,n%)
  return Map(color.match(/\d+(\.\d+)?\%?/g),
   function(x){ return parseInt(x.indexOf("%") > 0 ? parseFloat(x, 10) * 2.55 : x, 10); }
  )
 }
 else
 {//color
  var mapping = {"red":"#FF0000"};//略
  color = mapping[color.toLowerCase()];
  if(color){
   return Map([color.substr(1, 2), color.substr(3, 2), color.substr(5, 2)],
    function(x){ return parseInt(x, 16); }
   )
  }
 }
  }
};

 

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)));
 }
}

//渐变对象
var ColorTrans = function(obj, options){
 
 this._obj = $(obj);
 this._timer = null;//定时器
 this._index = 0;//索引
 this._colors = [];//颜色集合
 this._grads = new ColorGrads();
 
 this.SetOptions(options);
 
 this.Speed = Math.abs(this.options.Speed);
 this.CssColor = this.options.CssColor;
 
 this._startColor = this.options.StartColor || CurrentStyle(this._obj)[this.CssColor];
 this._endColor = this.options.EndColor;
 this._step = Math.abs(this.options.Step);
 
 this.Reset();
 this.SetColor();
};
ColorTrans.prototype = {
  //设置默认属性
  SetOptions: function(options) {
 this.options = {//默认值
  StartColor: "",//开始颜色
  EndColor: "#000",//结束颜色
  Step:  20,//渐变级数
  Speed:  20,//渐变速度
  CssColor: "color"//设置属性（Scripting属性）
 };
    Extend(this.options, options || {});
  },
  //重设颜色集合
  Reset: function(color) {
 //修改颜色后必须重新获取颜色集合
 color = Extend({ StartColor: this._startColor, EndColor: this._endColor, Step: this._step }, color || {});
 //设置属性
 this._grads.StartColor = this._startColor = color.StartColor;
 this._grads.EndColor = this._endColor = color.EndColor;
 this._grads.Step = this._step = color.Step;
 //获取颜色集合
 this._colors = this._grads.Create();
 this._index = 0;
  },
  //颜色渐入
  FadeIn: function() {
 this.Stop(); this._index++; this.SetColor();
 if(this._index < this._colors.length - 1){
  this._timer = setTimeout(Bind(this, this.FadeIn), this.Speed);
 }
  },
  //颜色渐出
  FadeOut: function() {
 this.Stop(); this._index--; this.SetColor();
 if(this._index > 0){
  this._timer = setTimeout(Bind(this, this.FadeOut), this.Speed);
 }
  },
  //颜色设置
  SetColor: function() {
 var color = this._colors[Math.min(Math.max(0, this._index), this._colors.length - 1)];
 this._obj.style[this.CssColor] = "rgb(" + color[0] + "," + color[1] + "," + color[2] + ")";
  },
  //停止
  Stop: function() {
 clearTimeout(this._timer);
  }
};

</script>
</head>
<body>
<style type="text/css">
#idGrads{}
#idGrads div{ font-size:0;height:1px;}
</style>
<div id="idGrads"> </div>
<script>
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 colors = new ColorGrads({ StartColor: "#fff", EndColor: "rgb(20,127,0)" }).Create();

forEach(colors.concat().concat(colors.reverse()), function(x){
 $("idGrads").innerHTML += "<div style=\"background-color:"+"rgb(" + x[0] + "," + x[1] + "," + x[2] + ");\"></div>";
})
</script>
<Br />
<Br />
<style type="text/css">
#idMenu{ background:#DBDBDB;text-align:center;line-height:25px; table-layout:fixed;}
#idMenu td{ cursor:pointer;}
</style>
<table id="idMenu" width="600" border="0" cellspacing="5" cellpadding="0">
 <tr>
  <td onclick="location.href='http://www.cnblogs.com/cloudgamer/archive/2008/07/21/ImgCropper.html'">Cropper</td>
  <td onclick="location.href='http://www.cnblogs.com/cloudgamer/archive/2009/01/06/Tween.html'">Tween</td>
  <td onclick="location.href='http://www.cnblogs.com/cloudgamer/archive/2008/12/24/Slider.html'">Slider</td>
  <td onclick="location.href='http://www.cnblogs.com/cloudgamer/archive/2008/12/03/Resize.html'">Resize</td>
  <td onclick="location.href='http://www.cnblogs.com/cloudgamer/archive/2008/11/17/Drag.html'">Drag</td>
 </tr>
</table>
<script>
forEach($("idMenu").getElementsByTagName("td"), function(x, i){
 var ct1 = new ColorTrans(x, { StartColor: "#666", EndColor: "#fff" });
 var ct2 = new ColorTrans(x, { StartColor: "#f6f6f6", EndColor: "rgb(20,150,0)", CssColor: "backgroundColor" });
 
 x.onmouseover = function(){ ct1.FadeIn(); ct2.FadeIn(); }
 x.onmouseout = function(){ ct1.FadeOut(); ct2.FadeOut(); }
})
</script>
<Br />
<Br />
<div id="idRandom" style="padding:10px;color:#fff; background-color:#CCC;">点击随机换颜色</div>
<script>
var ctRandom = new ColorTrans("idRandom", { EndColor: "#CCC", CssColor: "backgroundColor" })

$("idRandom").onclick = function(){
 var rgb = Map([1,1,1], function(){ return Math.floor((Math.random() * 255)); } );
 ctRandom.Reset({ StartColor: this.style.backgroundColor, EndColor: "rgb(" + rgb[0] + "," + rgb[1] + "," + rgb[2] + ")" })
 ctRandom.FadeIn();
}
</script>
</body>
</html>

样本效果：



Cropper Tween Slider Resize Drag


点击随机换颜色

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