Opencv实现图像旋转，非常简单，几行代码

opencv实现图片旋转功能，非常简单，几行代码即可：

#include
#include
#include
using namespace std;
using namespace cv;
inline double cpu_time(){
    return clock()*1000/CLOCKS_PER_SEC; 
}
//图片旋转操作 
void imrotate(Mat& img, Mat& newIm, double angle){
    int len = max(img.cols, img.rows);
    Point2f pt(len/2.,len/2.);
    Mat r = getRotationMatrix2D(pt,angle,1.0);
    warpAffine(img,newIm,r,Size(len,len));
    //better performance : 
    //Point2f pt(img.cols/2.,img.rows/2.);
    //Mat r = getRotationMatrix2D(pt,angle,1.0);
    //warpAffine(img,newIm,r,img.size());
}
int main(){
    Mat img = imread("1.jpg");
    //resize(img,img,Size(256,256));
    Mat newIm;
    double t1,t2;
    t1 = cpu_time();
    //调用旋转方法，模仿matlab，取名为imrotate
    imrotate(img,newIm,15);
    t2 = cpu_time();
    cout<<"Rotate one image cost: "<" ms"<"Rotate");
    imshow("Rotate",newIm);
    waitKey(10000);
    const string save_name = "rotate.jpg";
    imwrite(save_name,newIm);
    return 0;
}

run in ubuntu 12.04