是否可以在svg矩形中设置负宽度？

Question

我想基于鼠标移动移动矩形.请参考以下链接.

http://atomicrobotdesign.com/blog_media/draw/draw1.html

在mousedown事件中获取矩形起始位置并开始拖动它将在鼠标移动事件中创建矩形.但是当我移动到先前的值(即移动到小于鼠标按下值时,它将返回负值),因此宽度变为负值.

上面的链接是画布矩形.但我创建了具有相同逻辑的svg矩形.

不支持矩形的负宽度？或者如何根据鼠标移动移动矩形？

什么出错了？

我的代码片段.

ChartMouseDown:function(e){

//       e = this.normalizeMouseEvent(e);


      var mousedownCords=this.calMousePosition(e);
      this.mouseDownX=mousedownCords.X;
      this.mouseDownY=mousedownCords.Y;

      this.chartMouseDownPoint= this.GetValuebyPoint(Math.abs(this.mouseDownX-this.model.m_AreaBounds.X),Math.abs(this.mouseDownY-(this.model.m_AreaBounds.Y + this.model.m_AreaBounds.Height)));
      this.zoomingX=true;

    },



ChartMouseMove: function (evt) {

    if( this.zoomingX)
    {

    var mouseMoveX,mouseMoveY;

     var mouseMoveCords=this.calMousePosition(evt);
      mouseMoveX=mouseMoveCords.X;
      mouseMoveY=mouseMoveCords.Y;
      $(this.ZoomAreaRect).remove();
      var width =  Math.abs(mouseMoveX - this.mouseDownX);
      var height = mouseMoveY - this.mouseDownY;
      var x;
      if(mouseMoveX > this.mouseDownX)
      x= this.mouseDownX;
      else
      x= mouseMoveX;

       this.ZoomAreaRect = document.createElementNS("http://www.w3.org/2000/svg", "rect");

        $(this.ZoomAreaRect).attr({
            'id': 'ZoomArea', 'x': x, 'y': this.model.m_AreaBounds.Y, 'width': width, 'height': this.model.m_AreaBounds.Height,
            'fill': 'gray', 'stroke-width': 1, 'stroke':'gray'
        });

       $(this.ZoomAreaRect).appendTo(this.SvgObject);

    }


 calMousePosition:function(e)
    {
     var matched = jQuery.uaMatch( navigator.userAgent );
     var browser = {};
     var mouseX,mouseY;
     if(matched.browser.toLowerCase()=="mozilla")
        {
        mouseX = (e.pageX)-  $(this.SvgObject).parent().offset().left;
        mouseY=  (e.pageY) - $(this.SvgObject).parent().offset().top;
        }
        else
        {
        mouseX =  (e.pageX +document.documentElement.scrollLeft)-$(this.SvgObject).offset().left;
        mouseY =  (e.pageY + document.documentElement.scrollTop) - $(this.SvgObject).offset().top;
        }

        return { X: mouseX, Y:mouseY};

    },

谢谢,

湿婆

Answer 1

• 画布规格对宽度或高度没有限制,因此如果它们是负的,则矩形将以相反的方向绘制.

• SVG规范说如果宽度或高度为负,则不绘制矩形.

如果要在SVG中实现此功能,则必须确保矩形宽度/高度始终为正,并相应地计算x/y.