怎么动态绘制一个带面积周长的矩形？

• 回答：

  动态拖放时的绘制事件：

  
  

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  function DynWorldDrawMatrix( pCustomEntity, pWorldDraw, curPt) {     //与用户交互在图面上提取一个点     var vBasePt = pCustomEntity.GetPoint("BasePoint");     //计算中心点位置     var centerPt = mxOcx.NewPoint();     {         centerPt.x = curPt.x + (vBasePt.x - curPt.x) / 2;         centerPt.y = curPt.y + (vBasePt.y - curPt.y) / 2;     }     //计算面积（取绝对值）     var arec = Math.abs(vBasePt.x - curPt.x) * Math.abs(vBasePt.y - curPt.y);     //计算周长     var girth = 2 * (Math.abs(vBasePt.x - curPt.x) + Math.abs(vBasePt.y - curPt.y));     //变换视区长度     var dHeigth = mxOcx.ViewLongToDocCoord(15);     //绘制一个单行文字     //参数一为文字的位置的X坐标 ；参数二为文字的位置的Y坐标 ；参数三为文字内容字符串     //参数四为文字高度；参数五为文字的旋转角度     //参数六为文字的水平对齐方式,0=kTextLeft,1=kTextCenter,2=kTextRight     //参数七文字的竖直对齐方式,1=kTextBottom,2=kTextVertMid,3=kTextTop     pWorldDraw.DrawText(centerPt.x, centerPt.y, "面积：" + arec.toFixed(2), dHeigth, 0, 1, 1);     pWorldDraw.DrawText(centerPt.x, centerPt.y, "周长：" + girth.toFixed(2), dHeigth, 0, 1, 3);     //绘制一个直线     //参数一直线的开始点x坐标，参数二直线的开始点y坐标，参数三直线的结束点x坐标，参数四直线的结束点y坐标     pWorldDraw.DrawLine (vBasePt.x, vBasePt.y, vBasePt.x, curPt.y);     pWorldDraw.DrawLine (vBasePt.x, curPt.y, curPt.x, curPt.y);     pWorldDraw.DrawLine (curPt.x, curPt.y, curPt.x, vBasePt.y);     pWorldDraw.DrawLine (curPt.x, vBasePt.y, vBasePt.x, vBasePt.y); }

  
  

  动态绘制矩形框：

  
  

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  function DynDrawMatrix() {     // 创建一个与用户交互取点的对象。     var point1 = mxOcx.GetPoint(false,0,0,"\n 点取开始点:");     if(point1 == null)     {         return;     }     var getSecondPt = mxOcx.NewComObject("IMxDrawUiPrPoint");     getSecondPt.message = "第二点";     getSecondPt.basePoint = point1;     //不开启皮筋效果     getSecondPt.setUseBasePt(false);     //调用     var spDrawData = getSecondPt.InitUserDraw("TestDynDrawMatrix");     // 设置动态绘制参数.     spDrawData.SetPoint("BasePoint", point1);     // 开始取第二个点。     if (getSecondPt.go() != 1)         return;     var ret = spDrawData.Draw(); }