创建空白图像

IplImage *temp_quad=cvCreateImage(cvGetSize(show_img1),8,1);
	for (int i=0;i<temp_quad->height;i++)
		for (int j=0;j<temp_quad->width;j++)
		{
			cvSet2D(temp_quad,i,j,cvScalar(255)); 
		}
	//将四点连线画出
	for(int i=0;i<4;i++)
	{
		cvLine(temp_quad,cvPoint(pts[i]->point->x,pts[i]->point->y),cvPoint(pts[(i+1)%4]->point->x,pts[(i+1)%4]->point->y),cvScalar(0),2);
	}
	cvSaveImage("1.BMP",temp_quad);