/**
 * @name jquery.todoo.loadthumb.js
 * @type jQuery
 * version 
 * @Author   :  todoo
 *
 * @ChangeList
 * ---------------------------------------------------
 * Date         Editor              ChangeReasons
 * 2009.8.25    todoo                添加简单方法
 * 2009.9.11    todoo                添加内容替换方法
**/
jQuery.fn.todooimg_resize = function(options) {
	options = $.extend({
		 tsrc : "",
		 twidth:20,
		 theigth:20,
		 diystr:"[img]"
	},options);
	var _self = this;
	_self.css({width:options.twidth,height:options.theigth});
	_self.html("图片加载中，请稍后……");
	var img = new Image();
	$(img).load(function(){
		imgDem = {};
		imgDem.w  = img.width;
		imgDem.h  = img.height;
		imgDem = $.imgResize({"w":options.twidth,"h":options.theigth},{"w":imgDem.w,"h":imgDem.h});
	var imgMargins = $.imgCenter({"w":options.twidth,"h":options.theigth},{"w":imgDem.w,"h":imgDem.h});
	var str='';
		str='<img src="'+options.tsrc+'" style="width:'+imgDem.w+';height:'+imgDem.h+';MARGIN-LEFT:'+imgMargins.l+';MARGIN-TOP:'+imgMargins.t+';"/>';
		//alert(str);
		//alert(options.diystr);
		oldstr="[img]"; //待替换字串
		targetstr=options.diystr.replace(oldstr,str)
		_self.html(targetstr);
		//alert(targetstr);
	}).attr("src", options.tsrc);
	return _self;
}
jQuery.imgResize = function(parentDem,imgDem){
	if(imgDem.w>0 && imgDem.h>0){
		var rate = (parentDem.w/imgDem.w < parentDem.h/imgDem.h)?parentDem.w/imgDem.w:parentDem.h/imgDem.h;
		if(rate <= 1){  
			imgDem.w = imgDem.w*rate;
		    imgDem.h = imgDem.h*rate;		
		}else{
			imgDem.w = imgDem.w;
			imgDem.h = imgDem.h;
		}
    }
	return imgDem;
}
jQuery.imgCenter = function(parentDem,imgDem){
	var left = (parentDem.w - imgDem.w)*0.5;
	var top = (parentDem.h - imgDem.h)*0.5;
	return { "l": left , "t": top};
}