JS实现颜色梯度与渐变效果完整实例

发布于 2017-07-12 02:05:13 | 110 次阅读 | 评论: 0 | 来源: 网友投递

JavaScript客户端脚本语言

Javascript 是一种由Netscape的LiveScript发展而来的原型化继承的基于对象的动态类型的区分大小写的客户端脚本语言，主要目的是为了解决服务器端语言，比如Perl，遗留的速度问题，为客户提供更流畅的浏览效果。

这篇文章主要介绍了JS实现颜色梯度与渐变效果,结合完整实例形式分析了js颜色渐变所涉及的数学运算与页面样式动态操作相关技巧,需要的朋友可以参考下

本文实例讲述了JS实现颜色梯度与渐变效果的方法。分享给大家供大家参考，具体如下：

运行效果图如下：

完整实例代码如下：


<!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=utf-8" />
<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){
 $("idGrads").innerHTML += "<div style=\"background-color:"+"rgb(" + x[0] + "," + x[1] + "," + x[2] + ");\"></div>";
})
</script>
<Br />
<Br />
<style type="text/css">
#idMenu{ background:#DBDBDB;text-align:center;line-height:25px; table-layout:fixed;}
#idMenu td{ cursor:pointer;}
</style>
<table id="idMenu" width="600" border="0" cellspacing="5" cellpadding="0">
 <tr>
 <td onclick="location.href='#'">Cropper</td>
 <td onclick="location.href='#'">Tween</td>
 <td onclick="location.href='#'">Slider</td>
 <td onclick="location.href='#'">Resize</td>
 <td onclick="location.href='#'">Drag</td>
 </tr>
</table>
<script>
forEach($("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>

PS：这里再为大家推荐几款本站的相关在线工具：

希望本文所述对大家JavaScript程序设计有所帮助。

JS实现颜色梯度与渐变效果完整实例

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