相关版本： OpenCV 2.1

 

#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(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; int angle = 75;     src = cvLoadImage("test.jpg");     dst = rotateImage(src, angle, false);     cvNamedWindow("dst", 1);     cvShowImage("dst", dst);     cvWaitKey(0);     cvReleaseImage(&src);     cvReleaseImage(&dst); return 0; }

　　基本是通过改写OpenCV的官方论坛来实现的，除了那个用于旋转的m矩阵不知何用。

　　基本思路是把图片通过设置ROI复制到一个更大的黑色背景的图片中去，然后再旋转之后在截取其中的最小的包含旋转过后的矩形