Drawing of OpenCV basic graphics and its random generation

#include <iostream>
#include <opencv2/core/core.hpp>
#include <opencv2/highgui/highgui.hpp>
#include <opencv2/opencv.hpp>


using namespace std;
using namespace cv;


Mat bgImage;
void Mylines() {
    Point p1 = Point(20, 30);
    Point p2;
    p2.x = 300;
    p2.y = 300;
    Scalar color = Scalar(0, 0, 255);
    line(bgImage, p1, p2, color, 1, LINE_AA);
}

void MyRectangle() {
    Rect rect = Rect(150, 30, 300, 350); // parameter: x, y, width, height
    
    rectangle(bgImage, rect, Scalar(255, 0, 0 ), 2, 8);
}

void MyEllipse() {
    ellipse(bgImage, Point(bgImage.cols / 2, bgImage.rows / 2), Size(bgImage.cols / 4, bgImage.rows / 6), 90, 0, 180, Scalar(0, 255, 0), 2, LINE_AA);
}


void MyCircle() {
    circle(bgImage, Point(bgImage.cols / 2, bgImage.rows / 2), 123, Scalar(0, 255, 255), 2, LINE_AA);
}

void MyPolygon() {
// Point pts [1] [5];
// pts [0] [0] = Point (100, 100);
// pts [0] [1] = Point (100, 200);
// pts [0] [2] = Point (200, 200);
// pts [0] [3] = Point (200, 100);
// pts [0] [4] = Point (100, 100);

    Point pts [5];
    pts [0] = Point (100, 100);
    pts [1] = Point (100, 200);
    pts [2] = Point (200, 200);
    pts [3] = Point (200, 100);
    pts [4] = Point (100, 100);
    
    // const Point* ppts[] = {pst[0]};
    const Point* ppts[] = {pts};
    int ppt[] = {5};
    Scalar color = Scalar(255, 100, 255);
    fillPoly(bgImage, ppts, ppt, 1, color, 8); // src, Point **pts, int *npts, int ncontours, color
}


void RandomLineDemo() {
    RNG rng(12345);
    Point pt1, pt2;
    Mat bg = Mat::zeros(bgImage.size(), bgImage.type());
    for (int i = 0; i < 10000; i++) {
        pt1.x = rng.uniform(0, bgImage.cols);
        pt2.x = rng.uniform(0, bgImage.cols);
        pt1.y = rng.uniform(0, bgImage.rows);
        pt2.y = rng.uniform(0, bgImage.rows);
        
        Scalar color = Scalar(rng.uniform(0, 255), rng.uniform(0, 255), rng.uniform(0, 255));
        
        if (waitKey(50) > 0) {
            break;
        }
        
        line(bg, pt1, pt2, color, 1, 8);
        imshow("random img", bg);
    }
    
}


int main() {
    //Mat src1, src2, gray_src, dst;
    bgImage = imread("/Users/apple/Desktop/test.jpg", IMREAD_COLOR);
    //src2 = imread("/Users/apple/Desktop/test2.jpg", IMREAD_COLOR);
    if (bgImage.empty()) { // if (!src.data())
        cout << "could not load image..." << endl;
        return -1;
    }
    
//    Mylines();
//    MyRectangle();
// MyEllipse ();
//    MyCircle();
    MyPolygon();
//    putText(bgImage, "Hello World!", Point(150, 50), CV_FONT_BLACK, 2, Scalar(123, 55, 200));
    imshow("output", bgImage);
//
//    RandomLineDemo();
    waitKey(0);
    
    return 0;
}