opencv保存选择图像中的区域

在自己建立行人检测的图像库时用到，参考别人的修改了一下：

 #include "opencv2/core/core.hpp"
 #include "opencv2/highgui/highgui.hpp"
 #include "opencv2/imgproc/imgproc.hpp"
 #include <stdio.h>
 using namespace cv;

 IplImage* org = ;
 IplImage* img = ;
 IplImage* tmp = ;
 IplImage* dst = ;
 static int n=;
 static char savename[];
 void on_mouse( int event, int x, int y, int flags, void* ustc)
 {
     static CvPoint pre_pt = {-,-};
     static CvPoint cur_pt = {-,-};
     CvFont font;
     cvInitFont(&font, CV_FONT_HERSHEY_SIMPLEX, 0.5, 0.5, , , CV_AA);
     char temp[];

　　　　char lenth_and_height[];//用于查看选区的宽度和高度

     if( event == CV_EVENT_LBUTTONDOWN )
     {
         cvCopy(org,img);
         sprintf(temp,"(%d,%d)",x,y);
         pre_pt = cvPoint(x,y);
         cvPutText(img,temp, pre_pt, &font, cvScalar(,, , ));
         cvCircle( img, pre_pt, ,cvScalar(,,,) ,CV_FILLED, CV_AA,  );
         cvShowImage( "img", img );
         cvCopy(img,tmp);
     }
     else if( event == CV_EVENT_MOUSEMOVE && !(flags & CV_EVENT_FLAG_LBUTTON))
     {
         cvCopy(tmp,img);
         sprintf(temp,"(%d,%d)",x,y);
         cur_pt = cvPoint(x,y);
         cvPutText(img,temp, cur_pt, &font, cvScalar(,, , ));
         cvShowImage( "img", img );
     }
     else if( event == CV_EVENT_MOUSEMOVE && (flags & CV_EVENT_FLAG_LBUTTON))
     {
         cvCopy(tmp,img);
         sprintf(temp,"(%d,%d)",x,y);
         cur_pt = cvPoint(x,y);
         cvPutText(img,temp, cur_pt, &font, cvScalar(,, , ));
         cvRectangle(img, pre_pt, cur_pt, cvScalar(,,,), , ,  );

         sprintf(lenth_and_height,"(Width:%d,Height:%d)",abs(cur_pt.x-pre_pt.x),abs(cur_pt.y-pre_pt.y));
         /*-----------------------------------------------------------------------------
          *
          *
          *  为了方便随时查看自己选区的宽度和高度，特意加了一个点，该点计算为取矩形窗左上点和右下点的中点
          *
          *
          *-----------------------------------------------------------------------------*/
         CvPoint origin;
         origin.x=(pre_pt.x+cur_pt.x)/;
         origin.y=(pre_pt.y+cur_pt.y)/;
         cvPutText(img,lenth_and_height, origin, &font, cvScalar(,, , ));

         cvShowImage( "img", img );
     }
     else if( event == CV_EVENT_LBUTTONUP )
     {
         cvCopy(tmp,img);
         sprintf(temp,"(%d,%d)",x,y);
         cur_pt = cvPoint(x,y);
         cvPutText(img,temp, cur_pt, &font, cvScalar(,, , ));
         cvCircle( img, cur_pt, ,cvScalar(,,,) ,CV_FILLED, CV_AA,  );
         cvRectangle( img, pre_pt, cur_pt, cvScalar(,,,), , ,  );
         cvShowImage( "img", img );
         cvCopy(img,tmp);
         int width=abs(pre_pt.x-cur_pt.x);
         int height=abs(pre_pt.y-cur_pt.y);
         if(width== || height==)
         {
             cvDestroyWindow("dst");
             return;
         }
         dst=cvCreateImage(cvSize(width,height),org->depth,org->nChannels);
         CvRect rect;
         if(pre_pt.x<cur_pt.x && pre_pt.y<cur_pt.y)
         {
             rect=cvRect(pre_pt.x,pre_pt.y,width,height);
         }
         else if(pre_pt.x>cur_pt.x && pre_pt.y<cur_pt.y)
         {
             rect=cvRect(cur_pt.x,pre_pt.y,width,height);
         }
         else if(pre_pt.x>cur_pt.x && pre_pt.y>cur_pt.y)
         {
             rect=cvRect(cur_pt.x,cur_pt.y,width,height);
         }
         else if(pre_pt.x<cur_pt.x && pre_pt.y>cur_pt.y)
         {
             rect=cvRect(pre_pt.x,cur_pt.y,width,height);
         }
         cvSetImageROI(org,rect);
         cvCopy(org,dst);
         cvResetImageROI(org);
         cvDestroyWindow("dst");
         cvNamedWindow("dst",);
         cvShowImage("dst",dst);

         sprintf(savename,"save%03d.jpg",n);

         cvSaveImage(savename,dst);
         n++;
     }
 }
 int main(int argc, char *argv[])
 {

     org=cvLoadImage(argv[],);
     img=cvCloneImage(org);
     tmp=cvCloneImage(org);
     cvNamedWindow("img",);
     cvSetMouseCallback( "img", on_mouse,  );

     cvShowImage("img",img);
     cvWaitKey();
     cvDestroyAllWindows();
     cvReleaseImage(&org);
     cvReleaseImage(&img);
     cvReleaseImage(&tmp);
     cvReleaseImage(&dst);
     return ;
 }

运行效果：