DrawFeedback

  void        
  TCanvasRectDragInteractor::DrawFeedback ()
  {
      unsigned long n = GetNumberOfPoints ();
      if ( n > 0 ) {
      
          MToolHandler* toolHandler = GetToolHandler ();
          MGraphic* oldFeedbackGraphic = toolHandler->OrphanFeedbackGraphic (true);
          TGrafBundle* bundle = NIL;
          if ( oldFeedbackGraphic ) 
              bundle = oldFeedbackGraphic->OrphanBundle ();
          else
              bundle = new TGrafBundle(new TColorPaint(TRGBColor(0.,0.,0.)),
                              TAttributeState::kFrame);
          delete oldFeedbackGraphic;
      
          TGRect r (GetFirstPoint(),GetLastPoint());
          r.OrderPoints ();
      
          TPolygon* newFeedbackGraphic = new TPolygon (r, bundle);
          TGRect bounds = newFeedbackGraphic->GetLooseFitBounds ();
          bounds.Inset (TGPoint(-1.,-1.));
          TGArea totalArea (bounds);
      
          toolHandler->AdoptFeedbackGraphic (newFeedbackGraphic, totalArea, totalArea);
          }
  }