《学习OpenCV》练习题第四章第三题a

 #include <highgui.h>
 #include <cv.h>
 #include "opencv_libs.h"

 #pragma comment (lib,"opencv_calib3d231d.lib")
 #pragma comment (lib,"opencv_contrib231d.lib")
 #pragma comment (lib,"opencv_core231d.lib")
 #pragma comment (lib,"opencv_features2d231d.lib")
 #pragma comment (lib,"opencv_flann231d.lib")
 #pragma comment (lib,"opencv_gpu231d.lib")
 #pragma comment (lib,"opencv_haartraining_engined.lib")
 #pragma comment (lib,"opencv_highgui231d.lib")
 #pragma comment (lib,"opencv_imgproc231d.lib")
 #pragma comment (lib,"opencv_legacy231d.lib")
 #pragma comment (lib,"opencv_ml231d.lib")
 #pragma comment (lib,"opencv_objdetect231d.lib")
 #pragma comment (lib,"opencv_ts231d.lib")
 #pragma comment (lib,"opencv_video231d.lib")

 /*
  *《学习OpenCV》第四章第三题a
  * 完成时间：22:17 3/30 星期六 2013
  */

 /* 矩形框 */
 CvRect rect;

 bool draw = false;   // 标记是否在画

 IplImage* img;
 IplImage * temp;
 IplImage * original;

 void draw_rect(IplImage* img, CvRect rect)
 {
     cvRectangle( img,
         cvPoint( rect.x, rect.y ),
         cvPoint( rect.x + rect.width, rect.y + rect.height),
         cvScalar( 0x00, 0x00, 0xff) );
     printf("draw\n");
 }

 // 鼠标回调函数
 void my_mouse_callback( int event, int x, int y, int flags, void* param)
 {
     IplImage* image = (IplImage*) param;

     switch( event )
     {
     case CV_EVENT_MOUSEMOVE:
         {
             if(draw)
             {
                 rect.width = x - rect.x;
                 rect.height = y - rect.y;
             }
         }
         break;
     case CV_EVENT_LBUTTONDOWN:
         {
             draw = true;
             rect = cvRect( x, y, ,  );
         }
         break;
     case CV_EVENT_LBUTTONUP:
         {
             draw = false;
             if(rect.width < )
             {
                 rect.x += rect.width;
                 rect.width *= -;
             }
             if(rect.height < )
             {
                 rect.y += rect.height;
                 rect.height *= -;
             }
             // draw
             draw_rect(image, rect);
         }
         break;
         // 在右键按下时清除
     case CV_EVENT_RBUTTONDOWN:
         cvCopyImage(original, img);
         printf("clear.\n");
         break;
     }
 }

 int main()
 {
     img = cvLoadImage( "lena.bmp",  );

     rect = cvRect( -, -, , );

     // 副本
     temp = cvCloneImage( img );
     original = cvCloneImage(img);

     cvNamedWindow("draw rect");
     cvSetMouseCallback("draw rect", my_mouse_callback, (void*)img);

     while()
     {
         cvCopyImage(img, temp);

         if(draw)
         {
             draw_rect( temp , rect );
         }

         cvShowImage( "draw rect", temp);

         if(cvWaitKey() == )
             break;
     }
     cvReleaseImage(&img);
     cvReleaseImage(&temp);
     cvReleaseImage(&original);
     cvDestroyAllWindows();

     return ;
 }

运行结果：