Draw circle on IplImage when cvSetMouseCallback event occures

Question

4.00/5 (1 vote)

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VS2010

Iam trying to draw circles on points where the user clicks on the image..below is my code..it doesn't draws the circle when clicked on the image.But when i add

cvCircle(shape,cvPoint(100,100),10,CV_RGB(0,255,0),-1);

inside main function it just draws the circle...(here i have given the x,y coordinates manually)

C++

IplImage* shape;

void mouseHandler(int event, int x, int y, int flags, void* param)
  {
    switch(event){
      case CV_EVENT_LBUTTONDOWN:
          printf("Left button clicked %i\ %i \n",x,y);
           cvCircle(shape,cvPoint(x,y),10,CV_RGB(0,255,0),-1);

          break;

      case CV_EVENT_RBUTTONDOWN:
        printf("Right BUTTON Clicked\n");
        break;

    }
}

int _tmain(int argc, _TCHAR* argv[])
{
   
    cvNamedWindow("Shapes",CV_WINDOW_AUTOSIZE);
     
    shape=cvLoadImage("bb.jpg");
    
      cvSetMouseCallback("Shapes",mouseHandler,0);

     
    cvShowImage("Shapes",shape);
    
    cvWaitKey(0);
   
    cvReleaseImage(&shape);
    cvDestroyAllWindows();

    return 0;
}

Does anyone know the reason?
Thankyou

Posted 25-Feb-13 4:24am

Dilan Shaminda

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Dilan Shaminda · Accepted Answer · 2013-03-02T04:14:00

i have found the solution myself..Hope this will help....

C#

int xC,yC;
int *Xvalues = new int[15];
int *Yvalues = new int[15];
int count = 0;
bool drawing_circle = false;

<pr>

C++

void draw_circle(IplImage* img, int x,int y)
  {
         cvCircle(img,cvPoint(x,y),1,CV_RGB(0,255,0),-1);
	 Xvalues[count] = x;
	 Yvalues[count] = y;
	 count++;

    }
}

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

	switch( event ){

		case CV_EVENT_LBUTTONDOWN:
			drawing_circle = true;
			xC = x;
			yC = y;
			break;
	}
}

C++

int _tmain(int argc, _TCHAR* argv[])
{

    cvNamedWindow("Shapes",CV_WINDOW_AUTOSIZE);

    shape=cvLoadImage("bb.jpg");

    cvSetMouseCallback( name, my_mouse_callback, (void*) image);


    cvShowImage("Shapes",shape);
    
      while( 1 ){
		
		if( drawing_box ) 
		{
			draw_circle( image, xC,yC );
			
		}
    cvWaitKey(0);

    cvReleaseImage(&shape);
    cvDestroyAllWindows();

    return 0;
}