opencv--convexHull（）用法

 #include
 #include
 #include

 using namespace cv;
 using namespace std;

 int main()
 {
     //先初始化变量
     Mat srcImage(Size(600, 600), CV_8UC3, Scalar(0));
     Mat saveImage;
     srcImage.copyTo(saveImage);
     RNG &rng = theRNG();

     char key;
     Point midPoint;
     //hull 变量用来存储点的序号
     vector<int> hull;
     while (1)
     {
         //因为下面是入栈操作，所以，需要在循环内为变量分配空间，否则，栈内的数据无法出栈
         vector points;
         //首先确定随机点的坐标，以及随机点落定的范围
         int count = (unsigned int)rng % 100 + 3;
         for (int i = 0; i < count; i++)
         {
             //确定随机点的范围
             midPoint.x = rng.uniform(srcImage.cols / 4, srcImage.cols * 3 / 4);
             midPoint.y = rng.uniform(srcImage.rows / 4, srcImage.rows * 3 / 4);
             points.push_back(midPoint);
         }


         //该用法结束后，hull将外围点的序号存放起来
         convexHull(Mat(points), hull, true);

         //绘制随机点
         for (int i = 0; i < points.size(); i++)
         {
             circle(srcImage, points[i], 0, Scalar(255, 255, 0), 3, 8);
         }

         //绘制凸包
         Point point0 = points[hull[hull.size() - 1]];
         for (int i = 0; i < hull.size(); i++)
         {
             Point curPoint = points[hull[i]];

             line(srcImage, point0, curPoint, Scalar(255, 255, 0), 3, 8);

             point0 = curPoint;
         }

         imshow("【显示窗口】", srcImage);

         //停止在没有按键事件发生时
         key = waitKey();
         if (key == 27)
             break;
         else
             srcImage = Scalar(0);
             /*saveImage.copyTo(srcImage);*/
     }

     return 0;
 }

按下空格键进行切换