鼠标画矩形openCV

 #include <cv.h>
 #include <highgui.h>
 #include <stdio.h>
 /*鼠标画矩形*/
     void my_mouse_callback(
         int event,int x,int y,int flag,void* param
         );

     CvRect box;
     bool drawing_box = false;

     void draw_box(IplImage* img,CvRect rect)
     {
         cvRectangle(
             img,
             cvPoint(box.x,box.y),
             cvPoint(box.x+box.width,box.y+box.height),
             cvScalar(0xff,0x00,0x00)
             );
     }

     int main()
     {
         box = cvRect(-,-,,);
         IplImage* image = cvCreateImage(
             cvSize(,),
             IPL_DEPTH_8U,

             );
         cvZero(image);
         IplImage* temp = cvCloneImage(image);

         cvNamedWindow("Box Example");

         cvSetMouseCallback(
             "Box Example",
             my_mouse_callback,
             (void*)image
             );

         while()
         {
             cvCopyImage(image,temp);
             if(drawing_box) draw_box(temp,box);
             cvShowImage("Box Example",temp);

             if(cvWaitKey()==) break;
         }

         cvReleaseImage(&image);
         cvReleaseImage(&temp);
         cvDestroyAllWindows();

     }

     void my_mouse_callback(
         int event,int x,int y,int flag,void* param
         )
     {
         IplImage* image = (IplImage*)param;

         switch (event)
         {
         case CV_EVENT_MOUSEMOVE:
             {
                 if(drawing_box)
                 {
                     box.width = x-box.x;
                     box.height = y-box.y;

                 }

             }
             break;
         case CV_EVENT_LBUTTONDOWN:
             {
                 drawing_box = true;
                 box = cvRect(x,y,,);
             }
             break;
         case CV_EVENT_LBUTTONUP:
             {
                 drawing_box = false;
                 if(box.width<)
                 {
                     box.x += box.width;
                     box.width*=-;
                 }
                 if(box.height<)
                 {
                     box.y+=box.height;
                     box.height*=-;
                 }
                 draw_box(image,box);
             }
             break;
         }
     }