用opencv画虚线框矩形

#include <opencv2/opencv.hpp>
 
using namespace std;
using namespace cv;
 
void  drawDashRect(CvArr* img,int linelength,int dashlength,CvRect* blob,CvScalar color,int thickness)
{
	int w=cvRound(blob->width);//width
	int h=cvRound(blob->height);//height


	int tl_x=cvRound(blob->x);//top left x
	int tl_y=cvRound(blob->y);//top  left y


    int totallength=dashlength+linelength;
	int nCountX=w/totallength;//
	int nCountY=h/totallength;//


	CvPoint start,end;//start and end point of each dash


	//draw the horizontal lines
	start.y=tl_y;
	start.x=tl_x;


	end.x=tl_x;
	end.y=tl_y;


	for (int i=0;i<nCountX;i++)
	{
	end.x=tl_x+(i+1)*totallength-dashlength;//draw top dash line
	  end.y=tl_y;
	start.x=tl_x+i*totallength;
	start.y=tl_y;
	cvLine(img,start,end,color,thickness);   
	}
for (int i=0;i<nCountX;i++)
{  
	start.x=tl_x+i*totallength;
	start.y=tl_y+h;
	end.x=tl_x+(i+1)*totallength-dashlength;//draw bottom dash line
	end.y=tl_y+h;
	cvLine(img,start,end,color,thickness);     
	}


	for (int i=0;i<nCountY;i++)
{  
	start.x=tl_x;
start.y=tl_y+i*totallength;
end.y=tl_y+(i+1)*totallength-dashlength;//draw left dash line
end.x=tl_x;
cvLine(img,start,end,color,thickness);     
}


for (int i=0;i<nCountY;i++)
{  
	start.x=tl_x+w;
	start.y=tl_y+i*totallength;
	end.y=tl_y+(i+1)*totallength-dashlength;//draw right dash line
	end.x=tl_x+w;
	cvLine(img,start,end,color,thickness);     
}


}

int main(int argc, char* argv[])
{
    
 IplImage *img = cvLoadImage( "F:\\chen\\车辆跟踪对比图\\blurcar4 0024.jpg");

 CvRect rect1 = cvRect(100,200,200,100);
 
drawDashRect(img,1,2,&rect1,CV_RGB(255,255,255),1);
 cvShowImage("1",img);

 cvWaitKey(0);
  
   
 
    return 0;
}

做对比实验时，经常用到虚线框，但是opencv中没有找到直接函数，所以就在网上看见大神写的，借过来用，怕以后忘记，所以现在记下来