js+jquery实现图片裁剪功能_jquery

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。

\
     \
     \
     \
     \
     \
     \
     \
       ')
   .bind("mousedown.r",function(e){self.start(e)})
   .appendTo(this.container[0]);
   this.tips = $('').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:"+parseInt(left) + "top:" + +parseInt(top) + "width:"+width+ "height:"+height+"");
  },
  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("left")),top:parseInt(block.css("top"))};
   if(action){
    this.fun = this[action];    
   }else{
    this.x = e.clientX - this.offset.left - this.blockOriginal.left ;
    this.y = e.clientY - this.offset.top - this.blockOriginal.top;
    move = true;
   }   
   ie
    &&this.block[0].setCapture();
   this.tips.show();
   $(document)
    .bind("mousemove.r",function(e){self.move(e,move)})
    .bind("mouseup.r",function(){self.end()});   
  },
  end  : function(){
   $(document)
    .unbind("mousemove.r")
    .unbind("mouseup.r");
   ie 
    &&this.block[0].releaseCapture();
   this.tips.hide(); 
  },
  move : function(e,isMove){
   window.getSelection
    ? window.getSelection().removeAllRanges()
    : document.selection.empty();
    
   var block = this.block; 
   if(isMove){
    var left = Math.max(0,e.clientX - this.offset.left - this.x);
    left = Math.min(left,this.offset.width - this.blockOriginal.width);
    var top = Math.max(0,e.clientY - this.offset.top - this.y);
    top = Math.min(top,this.offset.height - this.blockOriginal.height);
    block.css({left:left,top:top});    
   }else{
    var offset = this.fun(e);
    block.css(offset);
   }
   
   this.setImg();
   this.moveCallBack();
  },
  down : function(e){
   var blockOriginal = this.blockOriginal,
    sTop = Math.max(dBody.scrollTop,dDoc.scrollTop), //出现垂直方向滚动条时候 要计算这个 
    offset = this.offset;
    
   if(e.clientY-offset.top>=blockOriginal.top-sTop){
    var height = Math.min(offset.height - blockOriginal.top,e.clientY-offset.top-blockOriginal.top+sTop),
     top = blockOriginal.top;
   }else{
    var height = Math.min(offset.top+blockOriginal.top-e.clientY-sTop,blockOriginal.top),
     top = Math.max(e.clientY - offset.top+sTop,0);
   }
   return {height:height, top:top};
  },
  up : function(e){
   var blockOriginal = this.blockOriginal,
    sTop = Math.max(dBody.scrollTop,dDoc.scrollTop),
    offset = this.offset;
   if(e.clientY-offset.top-blockOriginal.height     var top = Math.max(e.clientY-offset.top+sTop,0),
     maxHeight = blockOriginal.top + blockOriginal.height,
     height = Math.min(maxHeight,blockOriginal.top + blockOriginal.height -(e.clientY-offset.top)-sTop);     
   }else{
    var height = Math.min(e.clientY-offset.top-blockOriginal.top-blockOriginal.height+sTop,offset.height-blockOriginal.top-blockOriginal.height),
     top = blockOriginal.top+blockOriginal.height;  
   }
   return {height:height, top:top};
  },
  left : function(e){
   var blockOriginal = this.blockOriginal,
    offset = this.offset;
    
   if(e.clientX - offset.left - blockOriginal.width - blockOriginal.left     var left  = Math.max(e.clientX - offset.left,0),
     width = Math.min(blockOriginal.left + blockOriginal.width,blockOriginal.left + blockOriginal.width -(e.clientX-offset.left));
   }else{
    var width = Math.min(e.clientX-offset.left-blockOriginal.left-blockOriginal.width,offset.width-blockOriginal.left-blockOriginal.width),
     left  = blockOriginal.left + blockOriginal.width;
   }
   return {left : left,  width : width};
  },
  right : function(e){
   var blockOriginal = this.blockOriginal,
    offset = this.offset;
   if(e.clientX-offset.left>=blockOriginal.left){
    var width = Math.min(offset.width - blockOriginal.left,e.clientX - offset.left - blockOriginal.left),
     left  = blockOriginal.left;
   }else{
    var width = Math.min(offset.left + blockOriginal.left - e.clientX,blockOriginal.left),
     left  = Math.max(e.clientX - offset.left,0);
   }
   return {left : left,  width : width};
  },
  rightDown : function(e){
   return $.extend(this.right(e),this.down(e));  
  },
  leftDown : function(e){
   return $.extend(this.left(e),this.down(e));
  },
  rightUp : function(e){
   return $.extend(this.right(e),this.up(e));
  },
  leftUp : function(e){
   return $.extend(this.left(e),this.up(e));
  },
  getValue : function(){
   var block = this.block;
   return {
    left   : parseInt(block.css("left")),
    top    : parseInt(block.css("top")),
    width  : block.width(),
    height : block.height()
   }
  }
 }
 $.fn.clip = function(options){
  options.container = this;
  return new clip(options);
 }
})();
 xx = $("#container").clip({
  imgC : $("#imgC")
 })

是不是很炫酷啊，小伙伴们，学学本示例的思路吧。