opencv 图像旋转——来自互联网。。

#include "cv.h"   
#include "highgui.h"   
#include "math.h"   
  
// clockwise 为true则顺时针旋转，否则为逆时针旋转   
IplImage* rotateImage(IplImage* src, int angle, bool clockwise)  
{  
    angle = abs(angle) % 180;  
    if (angle > 90)  
    {  
        angle = 90 - (angle % 90);  
    }  
    IplImage* dst = NULL;  
    int width =  
        (double)(src->height * sin(angle * CV_PI / 180.0)) +  
        (double)(src->width * cos(angle * CV_PI / 180.0 )) + 1;  
    int height =  
        (double)(src->height * cos(angle * CV_PI / 180.0)) +  
        (double)(src->width * sin(angle * CV_PI / 180.0 )) + 1;  
    int tempLength = sqrt((double)src->width * src->width + src->height * src->height) + 10;  
    int tempX = (tempLength + 1) / 2 - src->width / 2;  
    int tempY = (tempLength + 1) / 2 - src->height / 2;  
    int flag = -1;  
  
    dst = cvCreateImage(cvSize(width, height), src->depth, src->nChannels);  
    cvZero(dst);  
    IplImage* temp = cvCreateImage(cvSize(tempLength, tempLength), src->depth, src->nChannels);  
    cvZero(temp);  
  
    cvSetImageROI(temp, cvRect(tempX, tempY, src->width, src->height));  
    cvCopy(src, temp, NULL);  
    cvResetImageROI(temp);  
  
    if (clockwise)  
        flag = 1;  
  
    float m[6];  
    int w = temp->width;  
    int h = temp->height;  
    m[0] = (float) cos(flag * angle * CV_PI / 180.);  
    m[1] = (float) sin(flag * angle * CV_PI / 180.);  
    m[3] = -m[1];  
    m[4] = m[0];  
    // 将旋转中心移至图像中间   
    m[2] = w * 0.5f;  
    m[5] = h * 0.5f;  
    //   
    CvMat M = cvMat(2, 3, CV_32F, m);  
    cvGetQuadrangleSubPix(temp, dst, &M);  
    cvReleaseImage(&temp);  
    return dst;  
}  
  
int main(int argc, char **argv)  
{  
    IplImage *src = 0;  
    IplImage *dst = 0;  
    // 旋转角度   
    int angle = 90;  
  
    src = cvLoadImage  ("Images\\cones\\imL.png",CV_LOAD_IMAGE_COLOR);  
    cvNamedWindow("src", 1);  
    cvShowImage("src", src);  
  
    dst = rotateImage(src, angle, false);  
    cvNamedWindow("dst", 2);  
    cvShowImage("dst", dst);  
    cvWaitKey(0);  
  
    cvReleaseImage(&src);  
    cvReleaseImage(&dst);  
    return 0;  
}