cvSetImageROI和cvResetImageROI

#include "cv.h"

#include "highgui.h"

int main()

{

IplImage* img=cvLoadImage("hello.jpg");

CvRect rect;

rect.x=0;

rect.y=0;

rect.height=48;

rect.width=48;

cvSetImageROI( img, rect );

cvNamedWindow( "tem image" );

cvShowImage("tem image",img);///显示pImg大小为48*48

//

IplImage *selimg=cvCreateImage(cvSize(rect.width,rect.height),8,3);

selimg=(IplImage*)cvClone(img);

cvNamedWindow( "select pImage");//可以看到selimg->width,selimg->height还是原图大小

cvShowImage("select pImage",selimg);///显示pImg大小为48*48

cvSaveImage("hello2.jpg",selimg);

cvResetImageROI(img);

cvWaitKey(0);

return 0;

}