图片的旋转与放缩

void size()
{
IplImage *src =cvLoadImage("first3.bmp",0);
IplImage *dst = 0;
int delta = 1;
int angle = 0;
int opt = 1;
double factor;

dst = cvCloneImage (src);
cvNamedWindow ("src", 1);
cvShowImage ("src", src);

for (;;)
{
float m[6];
// Matrix m looks like:
//
// [ m0 m1 m2 ] ===> [ A11 A12 b1 ]
// [ m3 m4 m5 ] [ A21 A22 b2 ]
//
CvMat M = cvMat (2, 3, CV_32F, m);
int w = src->width;
int h = src->height;
if (opt)// 旋转加缩放
factor = (cos (angle * CV_PI / 180.) + 1.0) * 2;
else// 仅仅旋转
factor = 1;
m[0] = (float) (factor * cos (-angle * 2 * CV_PI / 180.));
m[1] = (float) (factor * sin (-angle * 2 * 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;
// dst(x,y) = A * src(x,y) + b
cvZero (dst);
cvGetQuadrangleSubPix (src, dst, &M);
cvNamedWindow ("dst", 1);
cvMoveWindow("dst",200,200);
cvShowImage ("dst", dst);
if (cvWaitKey (1) == 27)//ESC
break;
angle = (int) (angle + delta) % 360;
}// for-loop
}