图像旋转与缩放

#include "cv.h"
#include "highgui.h"
#include "math.h"
int main (int argc, char **argv)
{
  IplImage *src = 0;
  IplImage *dst = 0;
 
  /* the first command line parameter must be image file name */
  if ((argc == 2) && (src = cvLoadImage (argv[1], -1)) != 0)
    {
      int delta = 1;
      int angle = 0;
      int opt = 0;  // 1： 旋转加缩放
      // 0:  仅仅旋转
      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);
   cvShowImage ("dst", dst);
   if (cvWaitKey (1) == 27) //ESC
     break;
   angle = (int) (angle + delta) % 360;
 }   // for-loop
    }
  return 0;
}[编辑]Python 版本
# -*- coding:utf-8 -*-
###########################################################
# OpenCV example
#
# 图像旋转与缩放
#
# By ChaiShushan 2008
###########################################################
 
import sys
import math
 
# 导入OpenCV模块
 
from opencv.cv import *
from opencv.highgui import *
 
if __name__ == '__main__':
 
    if len(sys.argv) == 2:
 
        src = cvLoadImage(sys.argv[1], -1)
        if not src: sys.exit(-1)
 
        delta = 1;
        angle = 90;
        opt = 0;    # 1： 旋转加缩放, 0: 仅仅旋转
        factor = 1;
 
        dst = cvCloneImage (src);
        cvNamedWindow ("src", 1);
        cvShowImage ("src", src);
 
        M = cvCreateMat (2, 3, CV_32F)
 
        while True:
 
            w = src.width;
            h = src.height;
 
            # factor大小未改变
 
            M[0,0] = factor * math.cos (-angle * 2 * CV_PI / 180.0);
            M[0,1] = factor * math.sin (-angle * 2 * CV_PI / 180.0);
            M[1,0] = -M[0,1];
            M[1,1] = M[0,0];
 
            # 将旋转中心移至图像中间
 
            M[0,2] = w * 0.5;
            M[1,2] = h * 0.5;
 
            # dst(x,y) = A * src(x,y) + b
 
            cvZero (dst);
            cvGetQuadrangleSubPix (src, dst, M);
 
            cvNamedWindow ("dst", 1);
            cvShowImage ("dst", dst);
 
            # ESC
 
            if cvWaitKey(10) == '\x1b':
                break
 
            angle = (angle + delta) % 360