javascript 线性渐变二- Javascript - 软晨网（RuanChen.com）

当前位置: 首页 > 图文教程 > 网络编程 > Javascript > javascript 线性渐变二

Javascript: js支持158、159开头的手机号的验证; javascript学习网址备忘; JScript的条件编译; [原创]站长必须要知道的javascript广告代码; js实现的点击超链显示隐藏层; JCalendar 日历控件 v1.0 beta[兼容IE&Firefox] 有文档和例子; JavaScript 不只是脚本; 把JS与CSS写在同一个文件里的书写方法; Javascript & DHTML 实例编程（教程）基础知识; Javascript & DHTML 实例编程（教程）DOM基础和基本API; javascript实现的一个图片转移效果; 用js实现键盘方向键翻页功能的代码; js实现DIV的一些简单控制; 用CSS+JS实现的进度条效果效果; 爱恋千雪-US-AscII加密解密工具（网页加密）下载; 用javascript实现始终保持打开同一个子窗口以及关闭父窗口同时自动关闭所有子窗口; 非常不错的页面特效建议大家看下; javascript Zifa FormValid 0.1表单验证代码打包下载; 实现javascript的延期执行或者重复执行的两个函数; 推荐一个不错的图片浏览效果

No. « ‹ 69 70 71 72 › »

技术文章搜索

关键字

Javascript 中的 javascript 线性渐变二

出处:互联网 整理: 软晨网（RuanChen.com） 发布: 2010-01-10 浏览: 332 ::

收藏到网摘: n/a

javascript线性渐变一 javascript 线性渐变三

上部分我们逐一分析了各浏览器的可行方法，这部分将搞鼓出一个统一的类来实现跨浏览器的线性渐变。先来IE的，这是最大的用户群，如果这部分开发不出来，基本可以说不用做了。IE虽然有Gradient滤镜，但对比其他浏览器的实现特弱，没有多重渐变（stop-color），不能实现角度渐变，而且还经常失效。我的思路是这样，假如有一个带文本的DIV，要实现多重线性渐变，我们首先得把它里面的文本取出来，然后里面放几个DIV，有几重就放几个，然后把它们渐变。如果是垂直渐变，这好办，什么也不用做，只需设置其滤镜与各个高就行了。如果水平，就让其浮动或绝对定位，放到适当的位置，设置其滤镜与宽。但渐变滤镜竟然会在浮动后或定位后失效，这是在使用透明滤镜时闻所未闻的。没有办法，祭出上古神器table。但设置长与宽时，使用style来设置是不顶用的，一定要用DOM属性。渐变则由它的td元素负责。为了去除table元素与td元素之间，td元素与其内容之间的空白，我们还得用到cellPadding与cellSpacing。

[Ctrl+A 全选提示:你可先修改部分代码,再按运行]

safari，chrome与opera打算都用SVG实现。为了减少函数的长度，特意搞了两个辅助函数。

复制代码代码如下:

 
var createSVG = function(tag){ 
return document.createElementNS("http://www.w3.org/2000/svg",tag); 
}; 
var attr= function(node,bag){ 
for(var i in bag){ 
if(bag.hasOwnProperty(i)) 
node.setAttribute(i,bag[i]) 
} 
}; 
var COSgradient = function(entity,stops,width,height,type){ 
var svg = createSVG("svg"); 
attr(svg,{width:width+"px",height:height+"px"}) 
entity.appendChild(svg); 
. 
var defs = createSVG("defs"); 
svg.appendChild(defs); 
var linearGradient = createSVG("linearGradient"); 
defs.appendChild(linearGradient); 
attr(linearGradient,{id:"nasami",x1:"0%",y1:"0%"}) 
if(type){ 
attr(linearGradient,{x2:"100%",y2:"0%"}) 
}else{ 
attr(linearGradient,{x2:"0%",y2:"100%"}) 
} 
for(var i=0,j=0,l=stops.length;i<l;i++,j++){ 
var offset = stops[i].split(",")[0] + "%", 
color = stops[i].split(",")[1], 
stop = createSVG("stop"); 
attr(stop,{offset:offset,"stop-color":color}); 
linearGradient.appendChild(stop); 
} 
var rect = createSVG("rect"); 
svg.appendChild(rect); 
attr(rect,{x:"0px",y:"0px",width:width+"px",height:height+"px",fill:"url(#nasami)"}); 
} 

firefox则利用其私有属性：

复制代码代码如下:

 
var FFgradient= function(entity,stops,width,height,type){ 
var cssText = ";background: -moz-linear-gradient(" 
cssText += type? "top,bottom," :"left,right,"; 
. 
for(var i=0,j=0,l=stops.length;i<l;i++,j++){ 
var offset = stops[i].split(",")[0] + "%", 
color = stops[i].split(",")[1]; 
cssText += "color-stop("+[offset,color]+")," 
} 
cssText = cssText.replace(/,$/,"")+") no-repeat;"; 
entity.style.cssText = cssText+"width:"+width+"px;height:"+height+"px;" 
} 

不过今天研磨一下，发现firefox还是支持SVG的线性渐变的，因此纠正我原来的观点。上面的函数只是作用一种实现手段放在这里，它并没有整合到我最终的版本中（虽然它比SVG实现短很多。）这样一来，在老一点版本的firefox中我们也能实现线性渐变了。
下面这个运行框里的渐变效果可在所有主流浏览器中正常运作。

<!doctype html>
<title>javascript线性渐变 by 司徒正美</title>
<meta charset="utf-8"/>
<meta name="keywords" content="javascript线性渐变 by 司徒正美" />
<meta name="description" content="javascript线性渐变 by 司徒正美" />
<style type="text/css">
#gradient{
width:800px;
height:100px;
border:1px solid red;
}
</style>
<script type="text/javascript">
var attr= function(node,bag){
for(var i in bag){
if(bag.hasOwnProperty(i))
node.setAttribute(i,bag[i])
}
};
//④使用IE滤镜实现渐变
function setFilter(el,start,end,type){
el.style.filter = "progid:DXImageTransform.Microsoft.Gradient(enabled='true',startColorstr="+start+",GradientType="+type+", endColorstr="+end+")";
}
//③每个渐变体的实现，是用table还是div
function createStop(parent,top,left,width,height,type){
if(type){
var table = document.createElement("table");
parent.appendChild(table);
var tr = table.insertRow(0),
td = tr.insertCell(0)
attr(table,{height:height+"px",width:width+"px",cellPadding:0,cellSpacing:0})
css(table,{position:"absolute",top:top+"px",left:left+"px"});
td.innerHTML =" ";
return td;
}
var div = document.createElement("div");
parent.appendChild(div);
css(div,{height:height+"px",width:width+"px"})
return div;
};
var createSVG = function(tag){
return document.createElementNS("http://www.w3.org/2000/svg",tag);
};
var css = function(node,bag){
var str = ";"
for(var i in bag){
if(bag.hasOwnProperty(i))
str += i+":"+bag[i]+";";
}
node.style.cssText = str;
}
var SVGgradient = function(entity,stops,width,height,type){
var svg = createSVG("svg");
attr(svg,{width:width+"px",height:height+"px"})
entity.appendChild(svg);
var defs = createSVG("defs");
svg.appendChild(defs);
var linearGradient = createSVG("linearGradient");
defs.appendChild(linearGradient);
attr(linearGradient,{id:"nasami",x1:"0%",y1:"0%"})
if(type){
attr(linearGradient,{x2:"100%",y2:"0%"})
}else{
attr(linearGradient,{x2:"0%",y2:"100%"})
}
for(var i=0,j=0,l=stops.length;i<l;i++,j++){
var offset = stops[i].split(",")[0] + "%",
color = stops[i].split(",")[1],
stop = createSVG("stop");
attr(stop,{offset:offset,"stop-color":color});
linearGradient.appendChild(stop);
}
var rect = createSVG("rect");
svg.appendChild(rect);
attr(rect,{x:"0px",y:"0px",width:width+"px",height:height+"px",fill:"url(#nasami)"});
}
//②渐变的具体实现，确定要使用多少渐变体，每个渐变体的颜色（是渐变色还是纯色）与长宽坐标
var IEgradient = function(entity,stops,width,height,type){
var offset,color,beforeColor,stopWidth,stopHeight,left,top,stop;
for(var i=0,j=0,l=stops.length;i<l;i++,j++){
offset = stops[i].split(",")[0];
color = stops[i].split(",")[1];
stopWidth = (offset/100 * width).toFixed(1);
stopHeight = (offset/100 * height).toFixed(1);
switch(i){
case 0 :
beforeColor = color;
left = stopWidth;
top = stopHeight;
if(offset != 0){
//插入一个纯色的table
stop = type? createStop(entity,0,0,stopWidth,height,type) :
createStop(entity,0,0,width,stopHeight,type);
css(stop,{background:color});
}
break;
case l-1:
//先插入一个渐变的table
var w2 = ((100-offset)/100 * width).toFixed(1),
h2 = ((100-offset)/100 * height).toFixed(1),
stop = type? createStop(entity,0,left,width - left -w2,height,type):
createStop(entity,0,0,width,height - top -h2,type);
setFilter(stop,beforeColor,color,type);
if(offset != 100){
//再插入一个纯色的table
var stop2 = type? createStop(entity,0,stopWidth,w2,height,type):
createStop(entity,0,0,width,h2,type);
css(stop2,{background:color});
}
break;
default :
//插入一个渐变的table
stop = type ? createStop(entity,0,left,stopWidth - left,height,type) :
createStop(entity,0,0,width,stopHeight-top,type);
setFilter(stop,beforeColor,color,type);
beforeColor = color;
left = stopWidth;
top = stopHeight;
break;
}
}
}
//①渐变的主体函数
var gradient = function(id){
var entity = document.getElementById(id),
options = arguments[1] || {},
width = options.width,
height = options.height,
type = options.type ,
stops = options["color-stop"];
css(entity,{position:"relative"});
var content = entity.innerHTML;
entity.innerHTML = "";
!+"\v1"? IEgradient(entity,stops,width,height,type):
SVGgradient(entity,stops,width,height,type)
var contentDiv = document.createElement("div");
css(contentDiv,{position:"absolute",top:0,left:0})
contentDiv.innerHTML = content;
entity.appendChild(contentDiv);
}
window.onload = function(){
gradient("gradient",{width:800,height:100,type:1,"color-stop":["0,red","16,orange","32,yellow","48,green","64,blue","80,indigo","100,violet"]})
}
</script>
<div id="gradient">javascript线性渐变 by 司徒正美 实现多重水平渐变效果</div>
https://developer.mozilla.org/en/SVG/Tutorial/Fill_Stroke_and_Gradients

[Ctrl+A 全选提示:你可先修改部分代码,再按运行]

再把它做成类。扼要说明一下：它的第一个参数为IE，第二个为哈希。哈希中的各参数都为必选的，width，height的单位为px；type为0或者1，0代表垂直，1为水平；color-stop代表渐变体，由一个字符串数组构成，每个字符串都是由数字加逗号加颜色值组成，数字表代偏移量，单位为%，颜色值可以是red,green等名词，也可以是六位或三位的哈希值。渐变体至少要有一个。

复制代码代码如下:

 
new Gradient("gradient",{width:800,height:100,type:0,"color-stop":["0,red", 
3."16,orange","32,yellow","48,green","64,blue","80,indigo","100,violet"]}) 

<!doctype html>
<title>javascript线性渐变 by 司徒正美</title>
<meta charset="utf-8"/>
<meta name="keywords" content="javascript线性渐变 by 司徒正美" />
<meta name="description" content="javascript线性渐变 by 司徒正美" />
<style type="text/css">
.gradient{
width:800px;
height:100px;
}
</style>
<script type="text/javascript">
var Gradient = function(id){
var entity = document.getElementById(id),
options = arguments[1] || {},
width = options.width,
height = options.height,
type = options.type ,
stops = options["color-stop"];
this.init(entity,stops,width,height,type);
}
Gradient.prototype ={
constructor: Gradient,
init: function(entity,stops,width,height,type) {
this.css(entity,{position:"relative"});
var content = entity.innerHTML;
entity.innerHTML = "";
!+"\v1"? this.IEgradient(entity,stops,width,height,type):
this.SVGgradient(entity,stops,width,height,type)
var contentDiv = document.createElement("div");
this.css(contentDiv,{position:"absolute",top:0,left:0})
contentDiv.innerHTML = content;
entity.appendChild(contentDiv);
},
css: function(node,bag){
var str = ";"
for(var i in bag){
if(bag.hasOwnProperty(i))
str += i+":"+bag[i]+";";
}
node.style.cssText = str;
},
attr: function(node,bag){
for(var i in bag){
if(bag.hasOwnProperty(i))
node.setAttribute(i,bag[i])
}
},
createSVG:function(tag){
return document.createElementNS("http://www.w3.org/2000/svg",tag);
},
setFilter:function(el,start,end,type){
el.style.filter = "progid:DXImageTransform.Microsoft.Gradient(enabled='true',startColorstr="+
start+",GradientType="+type+", endColorstr="+end+")";
},
createStop:function(parent,top,left,width,height,type){
if(type){
var table = document.createElement("table");
parent.appendChild(table);
var tr = table.insertRow(0),
td = tr.insertCell(0)
this.attr(table,{height:height+"px",width:width+"px",cellPadding:0,cellSpacing:0})
this.css(table,{position:"absolute",top:top+"px",left:left+"px"});
td.innerHTML =" ";
return td;
}
var div = document.createElement("div");
parent.appendChild(div);
this.css(div,{height:height+"px",width:width+"px"})
return div;
},
IEgradient:function(entity,stops,width,height,type){
var offset,color,beforeColor,stopWidth,stopHeight,left,top,stop;
for(var i=0,j=0,l=stops.length;i<l;i++,j++){
offset = stops[i].split(",")[0];
color = this.hex(stops[i].split(",")[1]);
stopWidth = (offset/100 * width).toFixed(1);
stopHeight = (offset/100 * height).toFixed(1);
switch(i){
case 0 :
beforeColor = color;
left = stopWidth;
top = stopHeight;
if(offset != 0){
//插入一个纯色的table
stop = type? this.createStop(entity,0,0,stopWidth,height,type) :
this.createStop(entity,0,0,width,stopHeight,type);
this.css(stop,{background:color});
}
break;
case l-1:
//先插入一个渐变的table
var w2 = ((100-offset)/100 * width).toFixed(1),
h2 = ((100-offset)/100 * height).toFixed(1),
stop = type? this.createStop(entity,0,left,width - left -w2,height,type):
this.createStop(entity,0,0,width,height - top -h2,type);
this.setFilter(stop,beforeColor,color,type);
if(offset != 100){
//再插入一个纯色的table
var stop2 = type? this.createStop(entity,0,stopWidth,w2,height,type):
this.createStop(entity,0,0,width,h2,type);
this.css(stop2,{background:color});
}
break;
default :
//插入一个渐变的table
stop = type ? this.createStop(entity,0,left,stopWidth - left,height,type) :
this.createStop(entity,0,0,width,stopHeight-top,type);
this.setFilter(stop,beforeColor,color,type);
beforeColor = color;
left = stopWidth;
top = stopHeight;
break;
}
}
},
SVGgradient:function(entity,stops,width,height,type){
var svg = this.createSVG("svg"),
id = "id" + (new Date().getTime()* Math.random()).toFixed(0);
this.attr(svg,{width:width+"px",height:height+"px"})
entity.appendChild(svg);
var defs = this.createSVG("defs");
svg.appendChild(defs);
var linearGradient = this.createSVG("linearGradient");
defs.appendChild(linearGradient);
this.attr(linearGradient,{id:id,x1:"0%",y1:"0%"})
if(type){
this.attr(linearGradient,{x2:"100%",y2:"0%"})
}else{
this.attr(linearGradient,{x2:"0%",y2:"100%"})
}
for(var i=0,j=0,l=stops.length;i<l;i++,j++){
var offset = stops[i].split(",")[0] + "%",
color = this.hex(stops[i].split(",")[1]),
stop = this.createSVG("stop");
this.attr(stop,{offset:offset,"stop-color":color});
linearGradient.appendChild(stop);
}
var rect = this.createSVG("rect");
svg.appendChild(rect);
this.attr(rect,{x:"0px",y:"0px",width:width+"px",height:height+"px",
fill:"url(#"+linearGradient.getAttribute("id")+")"});
},
hex:function(value){
if(/^#/.test(value)){
value = value.replace('#', '');
return "#" + (value.length == 3 ? value.replace(/^(\w)(\w)(\w)$/, '$1$1$2$2$3$3') : value);
}
return value;
}
}
window.onload = function(){
new Gradient("text1",{width:800,height:100,type:1,"color-stop":["0,red","16,orange","32,yellow","48,green","64,blue","80,indigo","100,violet"]})
new Gradient("text2",{width:800,height:100,type:0,"color-stop":["0,red","16,orange","32,yellow","48,green","64,blue","80,indigo","100,violet"]})
}
</script>
<div id="text1" class="gradient">javascript线性渐变 by 司徒正美 实现多重水平渐变效果</div>
<div id="text2" class="gradient">javascript线性渐变 by 司徒正美 实现多重垂直渐变效果</div>

[Ctrl+A 全选提示:你可先修改部分代码,再按运行]

javascript线性渐变一 javascript 线性渐变三

Javascript 中的 javascript 线性渐变二

评论 (0) All