//环境：VS2010 + OpenCV 2.3.1
#include "stdafx.h"
#include <cv.h>
#include <highgui.h>
#include <math.h>
#include <stdlib.h>
#include <stdio.h>
using namespace cv;
Mat src, dst, tmp;
char* window_name = "Pyramids Demo";
int _tmain(int argc, _TCHAR* argv[])
{
 printf("\n Zoom In-Out demo \n");
 printf("-------------------- \n");
 printf("*[u]-> Zoom in \n");
 printf("*[d]-> Zoom out \n");
 printf("*[ESC]-> Close program \n\n");
 src = imread("D:\\fruits.jpg");
 if(!src.data)
 {
  printf("No data!--Exiting the program \n");
  return -1;
 }
 tmp = src;
 dst = tmp;
 namedWindow(window_name,CV_WINDOW_AUTOSIZE);
 imshow(window_name,dst);
 while(true)
 {
  int c;
  c = waitKey(10);
  if((char)c == 27)
  {
   break;
  }
  if((char)c == 'u')
  {
   pyrUp(tmp,dst,Size(tmp.cols * 2,tmp.rows * 2));
   printf("** Zoom In:Image x 2\n");
  }
  else if((char)c == 'd')
  {
   pyrDown(tmp,dst,Size(tmp.cols / 2,tmp.rows / 2));
   printf("**Zoom Out:Image / 2\n");
  }
  imshow(window_name,dst);
  tmp = dst;
 }
 return 0;
}

#pragma comment(lib,"opencv_highgui231d.lib")