First knowledge of opencv4.x --- image perspective transformation

// Image perspective transformation 
#include <stdio.h>
#include <iostream>
#include <string>
#include <opencv2\opencv.hpp>
using namespace std;
using namespace cv;

int main()
{
    
	// Perspective transformation of image , need 3x3 The rotation matrix of , in total 9 Parameters , Through the original image and the transformed correspondence 4 A point can be constructed 12 Solve equations 9 Parameters 
	Mat img = imread("noobcvqr.png");
	// Note that boundary points cannot be used , The image is 628*628, The maximum value is 627, Otherwise, an error will be reported 
	Point2f src[4] = {
     Point2f(94,374),Point2f(507,380),Point2f(1,623) ,Point2f(627,627) };
	Point2f dst[4] = {
     Point2f(0,0),Point2f(627,0),Point2f(0,627) ,Point2f(627,627) };
	Mat rotation, img_dst;
	rotation = getPerspectiveTransform(src, dst);
	warpPerspective(img, img_dst, rotation, Size(img.cols, img.rows));
	namedWindow(" Original picture ", WINDOW_NORMAL);
	imshow(" Original picture ", img);
	namedWindow(" Perspective transformation ", WINDOW_NORMAL);
	imshow(" Perspective transformation ", img_dst);
	waitKey(0);
	return 0;
}