[vtkusers] vtkSliderWidget subclassing

[minjun]

hello, 

i want to show mouse cursor(VTK_CURSOR_HAND) at hovering vtkSliderWidget

below shows what I want to do. // vtkButtonWidget.cxx

void vtkButtonWidget::MoveAction(vtkAbstractWidget *w)
{
  vtkButtonWidget *self = reinterpret_cast<vtkButtonWidget*>(w);

  int X = self->Interactor->GetEventPosition()[0];
  int Y = self->Interactor->GetEventPosition()[1];

  // Motion while selecting is ignored
  if ( self->WidgetState == vtkButtonWidget::Selecting )
  {
    self->EventCallbackCommand->SetAbortFlag(1);
    return;
  }

  // Get the new state and compare it to the old
  int renderRequired = 0;
  int state = self->WidgetRep->ComputeInteractionState(X, Y);
  if ( self->WidgetState == vtkButtonWidget::Hovering )
  {
    if ( state == vtkButtonRepresentation::Outside )
    {
      renderRequired = 1;
      if ( self->ManagesCursor )
      {
        self->RequestCursorShape(VTK_CURSOR_DEFAULT);
      }
      self->WidgetRep->Highlight(vtkButtonRepresentation::HighlightNormal);
      self->WidgetState = vtkButtonWidget::Start;
    }
  }
  else //state is Start
  {
    if ( state == vtkButtonRepresentation::Inside )
    {
      renderRequired = 1;
      if ( self->ManagesCursor )
      {
        self->RequestCursorShape(VTK_CURSOR_HAND);
      }
     
self->WidgetRep->Highlight(vtkButtonRepresentation::HighlightHovering);
      self->WidgetState = vtkButtonWidget::Hovering;
      self->EventCallbackCommand->SetAbortFlag(1);
    }
  }

  if ( renderRequired )
  {
    self->Render();
  }
}

I got an idea here, 

I want to show the mouse cursor by modifying below code(vtkSliderWidet.cxx)

void vtkSliderWidget::MoveAction(vtkAbstractWidget *w)
{
  vtkSliderWidget *self = reinterpret_cast<vtkSliderWidget*>(w);

  // See whether we're active
  if ( self->WidgetState == vtkSliderWidget::Start ||
       self->WidgetState == vtkSliderWidget::Animating )
  {
    return;
  }

  // Definitely moving the slider, get the updated position
  double eventPos[2];
  eventPos[0] = self->Interactor->GetEventPosition()[0];
  eventPos[1] = self->Interactor->GetEventPosition()[1];
  self->WidgetRep->WidgetInteraction(eventPos);

  // Interact, if desired
  self->EventCallbackCommand->SetAbortFlag(1);
  self->InvokeEvent(vtkCommand::InteractionEvent,NULL);
  self->Render();
}

To use modified code, I think I should use subclassing.

But after modifying the code, I don't know how to apply it.

//vtkSliderWidget.cxx
vtkSliderWidget::vtkSliderWidget()
{
  // Set the initial state
  this->WidgetState = vtkSliderWidget::Start;

  // Assign initial values
  this->AnimationMode = vtkSliderWidget::Jump;
  this->NumberOfAnimationSteps = 24;

  // Okay, define the events
  this->CallbackMapper->SetCallbackMethod(vtkCommand::LeftButtonPressEvent,
                                          vtkWidgetEvent::Select,
                                          this,
vtkSliderWidget::SelectAction);
  this->CallbackMapper->SetCallbackMethod(vtkCommand::MouseMoveEvent,
                                          vtkWidgetEvent::Move,
                                          this,
vtkSliderWidget::MoveAction);
 
this->CallbackMapper->SetCallbackMethod(vtkCommand::LeftButtonReleaseEvent,
                                          vtkWidgetEvent::EndSelect,
                                          this,
vtkSliderWidget::EndSelectAction);
}

i'm now use callback event as below

vtkSmartPointer<vtkSliderCallback> callback =
vtkSmartPointer<vtkSliderCallback>::New();
AddObserver(vtkCommand::InteractionEvent, callback);

But I want to know how to call the modified moveAction event.

If you have an idea about this issue, I would like help.

Thanks for reading. :)




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