이미지 회전
#include "iostream"
#include "opencv2/imgproc.hpp"
#include "opencv2/imgcodecs.hpp"
#include "opencv2/highgui.hpp"
using namespace std;
using namespace cv;
int main(int argc, char** argv)
{
//Mat src = imread("Lenna.png");
Mat src = imread("cloud.jpg");
Mat dst;
Point center = Point(src.cols / 2, src.rows / 2);
double angle = 45.0;
double scale = 1.0;
Mat rot_mat = getRotationMatrix2D(center, angle, scale);
warpAffine(src, dst, rot_mat, src.size());
imshow("src", src);
imshow("dst", dst);
waitKey(0);
return 0;
}