openCv 图像顺时针、逆时针旋转

通过下面这个函数调用

Rotate90(workImg,270); //顺时针旋转

Rotate90(workImg,90); //逆时针旋转

实现，其实用该函数旋转任意度数对正方形图都ok，只是长方形图旋转后会有拉伸部分，不好掌握新图的长宽。

void Rotate90(IplImage *workImg,int angle)

{

    int opt = ;                            //  1: 加缩放   0: 仅旋转

    double factor;                          //  缩放因子

    IplImage *pImage;

    IplImage *pImgRotation = NULL;

    pImage = workImg;

    pImgRotation = cvCloneImage(workImg);

    angle=-angle;

    //  创建 M 矩阵

    float m[];

    //      Matrix m looks like:

    //      [ m0  m1  m2 ] ----> [ a11  a12  b1 ]

    //      [ m3  m4  m5 ] ----> [ a21  a22  b2 ]

    CvMat M = cvMat(,,CV_32F,m);

    int w = workImg->height;

    int h = workImg->width;

    if (opt) factor = (cos(angle*CV_PI/.)+1.0)*;

    else factor = ;

    m[] = (float)(factor*cos(-angle*CV_PI/.));

    m[] = (float)(factor*sin(-angle*CV_PI/.));

    m[] = -m[];

    m[] =  m[];

    //  将旋转中心移至图像中心

    m[] = w*0.5f;

    m[] = h*0.5f;

    //---------------------------------------------------------

    //  dst(x,y) = A * src(x,y) + b

    cvZero(pImgRotation);

    cvGetQuadrangleSubPix(pImage,pImgRotation,&M);

    //---------------------------------------------------------

    cvNamedWindow("Rotation Image");

    cvFlip(pImgRotation);

    cvShowImage("Rotation Image",pImgRotation);

    cvReleaseImage( &pImgRotation );

    cvWaitKey();

    cvDestroyWindow("Rotation Image");

}

from: http://blog.csdn.net/abcjennifer/article/details/7269968