jQuery自定义图片缩放拖拽插件imageQ实现方法(附demo源码下载)

/**
 *
 * <a href="http://lib.csdn.net/base/22" class='replace_word' title="jQuery知识库" target='_blank' style='color:#df3434; font-weight:bold;'>jQuery</a> imageQ plugin
 * @name jquery-imageQ.js
 * @author Q
 * @date 2011-01-19
 * maxRatio 最大放大比例
 * minRatio 最小缩小比例
 * changeRadio 每次变化幅度
 * picUrl:图片地址,
 * picWidth:图片宽度,
 * picHeight:图片高度,
 * reset:是否重设图片
 *
 */
(function($){
  var status = false;
  $.fn.imageQ = function(options){
    var defaults = {
      maxRatio:4,
      minRatio:4,
      changeRadio:0.2,
      picUrl:'',
      picWidth:306,
      picHeight:372,
      reset:false
    }
    var options=jQuery.extend(defaults,options);
    return this.each(function(){
      status = true;
      $(this).attr('src','');
      $(this).attr('src',options.picUrl);
      var naturalwidth = options.picWidth;
      var naturalheight = options.picHeight;
      var minwidth = Math.round(naturalwidth/options.minRatio);
      var minheight = Math.round(naturalheight/options.minRatio);
      var maxwidth = Math.round(naturalwidth*options.maxRatio);
      var maxheight = Math.round(naturalheight*options.maxRatio);
      if(options.reset)
      {
        $("#wrapDiv").css("width",naturalwidth+"px");
        $("#wrapDiv").css("height",naturalheight+"px");
        $("#wrapDiv").css("top",'0px');
        $("#wrapDiv").css("left",'0px');
      }
      else
      {
        $(this).css("width","100%");
        $(this).css("height","100%");
        $(this).wrap("<div id='wrapDiv' style='-moz-user-select: none;width:"+naturalwidth+"px;height:"+naturalheight+"px;cursor:move;position:relative;top:0px;left:0px;visibility: visible;' ondragstart='return false;' onselectstart='return false;'></div>");
        $("#wrapDiv").before('<div style="visibility: visible; height: 26px; width: 78px; display: block; position: absolute; line-height: 1px; cursor: pointer; left: 0px; top: 0px;z-index:1;"><div id="plusTool"></div><div id="minusTool"></div><div id="moveTool"></div></div>');
        //$("#wrapDiv").append('<div style="display: block; position: relative; left: 0px; top: 0px; width: 100%; height: 100%; -moz-user-select: none;" id="uploaduserpng"></div>');
        $("#plusTool").attr('title','放大');
        $("#minusTool").attr('title','缩小');
        $("#moveTool").attr('title','拖动');
        $("#plusTool").bind("click",function(){
          _changeOperate('plus');
        });
        $("#minusTool").bind("click",function(){
          _changeOperate('minus');
        });
        $("#moveTool").bind("click",function(){
          _changeOperate('move');
        });
        function plusOperate()
        {
          $("#wrapDiv").unbind();
          $("#wrapDiv").unbind();
          $("#wrapDiv").bind("click",function(){
              var h = $("#wrapDiv").height();
              var w = $("#wrapDiv").width();
              if(Math.round(h*(1+options.changeRadio)) >= maxheight)
              {
                var newH = maxheight;
              }
              else
              {
                var newH = Math.round(h*(1+options.changeRadio));
              }
              if(Math.round(w*(1+options.changeRadio)) >= maxwidth)
              {
                var newW = maxwidth;
              }
              else
              {
                var newW = Math.round(w*(1+options.changeRadio));
              }
              $("#wrapDiv").css("width",newW+"px");
              $("#wrapDiv").css("height",newH+"px");
            });
        }
        function minusOperate()
        {
          $("#wrapDiv").unbind();
          $("#wrapDiv").unbind();
          $("#wrapDiv").bind("click",function(){
              var h = $("#wrapDiv").height();
              var w = $("#wrapDiv").width();
              if(Math.round(h*(1-options.changeRadio)) <= minheight)
              {
                var newH = minheight;
              }
              else
              {
                var newH = Math.round(h*(1-options.changeRadio));
              }
              if(Math.round(w*(1-options.changeRadio)) <= minwidth)
              {
                var newW = minwidth;
              }
              else
              {
                var newW = Math.round(w*(1-options.changeRadio));
              }
              $("#wrapDiv").css("width",newW+"px");
              $("#wrapDiv").css("height",newH+"px");
            });
        }
        function moveOperate()
        {
          $("#wrapDiv").unbind();
          var _move = false;
          var _x,_y;
          $("#wrapDiv").bind("mousedown",function(e){
            _setCursor('grabbing');
            _move = true;
            if(!document.all)
            {
              _x = e.pageX - parseInt($("#wrapDiv").css("left"));
              _y = e.pageY - parseInt($("#wrapDiv").css("top"));
            }
            else
            {
              var pagex = e.clientX+(document.documentElement.scrollLeft?document.documentElement.scrollLeft:document.body.scrollLeft);
              var pagey = e.clientY+(document.documentElement.scrollTop?document.documentElement.scrollTop:document.body.scrollTop);
              _x = pagex - parseInt($("#wrapDiv").css("left"));
              _y = pagey - parseInt($("#wrapDiv").css("top"));
            }
          });
          $("#wrapDiv").bind("mouseup",function(e){
            _setCursor('grab');
            _move = false;
          });
          $("#wrapDiv").bind("mousemove",function(e){
            if(_move)
            {
              if(!document.all)
              {
                var pagex = e.pageX;
                var pagey = e.pageY;
              }
              else
              {
                var pagex = e.clientX+(document.documentElement.scrollLeft?document.documentElement.scrollLeft:document.body.scrollLeft);
                var pagey = e.clientY+(document.documentElement.scrollTop?document.documentElement.scrollTop:document.body.scrollTop);
              }
              var x = pagex-_x;
              var y = pagey-_y;
              $("#wrapDiv").css("top",y);
              $("#wrapDiv").css("left",x);
            }
          });
        }
        function _setCursor(type){
          $("#wrapDiv").css("cursor","url('images/cursors/"+type+".cur'),default");
        }
        function _changeOperate(operate)
        {
          if(operate == 'plus')
          {
            _setCursor('zoom-in');
            plusOperate();
          }
          if(operate == 'minus')
          {
            _setCursor('zoom-out');
            minusOperate();
          }
          if(operate == 'move')
          {
            _setCursor('grab');
            moveOperate();
          }
        }
      }
    });
  };
  $.fn.imageQ.getStatus = function()
  {
    return status;
  };
})(jQuery);