现在我们在使用各大网站的个人中心时，都有个上传个人头像的功能。用户在上传了个人照片之后，可能不符合网站的要求，于是要求用户对照片进行裁剪，最终根据用户裁剪的尺寸生成头像。这个功能真是太棒了，原来不懂js的时候，感觉很神奇，太神奇了。心想哪天要是自己也能搞明白这里面的技术，那该多牛呀~大家是不是也有何我一样的想法呀~哈哈~~
下面我们就来用javascript来实现这个功能吧。
<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>clip</title>
<style type="text/css">
*{ padding:0; margin:0;}
ul{ list-style-type:none; overflow:hidden; zoom:1; width:1000px; margin:30px auto; }
li{ float:left; width:500px;}
#container{width:480px; height:480px; margin:0 auto; border:1px solid #999; position:relative;background:url(http://images.cnblogs.com/cnblogs_com/wtcsy/192373/r_xx.jpg);}
#container .block{height:100px; width:100px; border:1px solid #000000; position:absolute; left:50px; top:50px; background:#fff;filter:alpha(opacity=30);opacity:0.3; cursor:move;}
#container .tips{ position:absolute; padding:5px; border:1px solid #ccc;background:#fff;filter:alpha(opacity=60);opacity:0.6; display:none; font-size:12px; color:#333; ;}
.tips span{ display:inline-block;zoom:1; width:28px;}
.rRightDown,.rLeftDown,.rLeftUp,.rRightUp,.rRight,.rLeft,.rUp,.rDown{
position:absolute;background:#f00;width:6px;height:6px;z-index:5;font-size:0;}
.rLeftDown,.rRightUp{cursor:ne-resize;}
.rRightDown,.rLeftUp{cursor:nw-resize;}
.rRight,.rLeft{cursor:e-resize;}
.rUp,.rDown{cursor:n-resize;}
.rRightDown{ bottom:-3px; right:-3px;}
.rLeftDown{ bottom:-3px; left:-3px;}
.rRightUp{ top:-3px; right:-3px;}
.rLeftUp{ top:-3px; left:-3px;}
.rRight{ right:-3px; top:50%}
.rLeft{ left:-3px; top:50%}
.rUp{ top:-3px; left:50%}
.rDown{ bottom:-3px; left:50%}
#imgC{ border:1px solid #CCC; width:0; height:0; margin:0 auto;background:url(http://images.cnblogs.com/cnblogs_com/wtcsy/192373/r_xx.jpg);}
.code {
background: none repeat scroll 0 0 #E3F4F9;
border: 1px solid #BAE2F0;
font: 12px "Courier New",Courier,monospace;
margin: 30px auto;
padding: 10px 10px 40px;
width:980px;
}
.code p{ height:24px; line-height:24px;}
.code span{ display:inline-block;zoom:1; margin-right:5px; width:85px; font-weight:bold; color:#00F}
</style>
</head>
<body>
<div class="code">
<div class="how">使用方法</div>
<p>$("#container").clip({
imgC : $("#imgC"),
blockClass : "block",
tipsClass : "tips"
});</p>
<p><span>imgC :</span> 表示裁剪图片的容器,也就是右边的图</p>
<p><span>blockClass :</span> block的样式名 也就是页面上的可以拖动的滑块的样式 因为怕和别的页面上的样式重名 默认是block</p>
<p><span>tipsClass :</span> tips的样式名 也就是页面上显示left width height top的那个span的样式名 默认是tips</p>
</div>
<ul>
<li>
<div id="container"></div>
</li>
<li>
<div id="imgC"></div>
</li>
</ul>
<script type="text/javascript" src="http://common.cnblogs.com/script/jquery.js"></script>
<script type="text/javascript">
(function(){
var dBody = document.body,
dDoc = document.documentElement,
ie = $.browser.msie;
ie&&($.browser.version=="6.0")
&&document.execCommand("BackgroundImageCache", false, true);
var clip = function(options){
this.init.call(this,options);
}
clip.prototype = {
options :{
moveCallBack : function(){},
blockClass : "block",
tipsClass : "tips"
},
init : function(options){
$.extend(this,this.options,options||{});
if(!this.container || !this.imgC){
return;
}
this.container = $(this.container);
var self = this;
this.block = $('<div class="'+this.blockClass+'">\
<div action="rightDown" class="rRightDown"></div>\
<div action="leftDown" class="rLeftDown"></div>\
<div action="rightUp" class="rRightUp"></div>\
<div action="leftUp" class="rLeftUp"></div>\
<div action="right" class="rRight"></div>\
<div action="left" class="rLeft"></div>\
<div action="up" class="rUp"></div>\
<div action="down" class="rDown" ></div>\
</div>')
.bind("mousedown.r",function(e){self.start(e)})
.appendTo(this.container[0]);
this.tips = $('<span class="'+this.tipsClass+'" />').appendTo(this.container[0]);
this.setImg();
},
setImg : function(){
var block = this.block;
var left = block.css("left"),
top = block.css("top"),
height = block.height(),
width = block.width();
this.imgC.css({
height: height,
width : width,
"background-position" : "-"+left+" -"+top
});
this.tips.html("left:<span>"+parseInt(left) + "</span>top:<span>" + +parseInt(top) + "</span>width:<span>"+width+ "</span>height:<span>"+height+"</span>");
},
start : function(e){
var $elem = $(e.target),
block = this.block,
self = this,
move = false,
container = this.container,
action = $elem.attr("action");
//这个 每次都要计算 基本dom结构的改变 浏览器的缩放 都会让里面的值发生改变
this.offset = $.extend({height:container.height(),width:container.width()},container.offset());
this.blockOriginal = {height:block.height(),width:block.width(),left:parseInt(block.css("le