Ho to check for left button single click event vs click and drag event

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6

Not sure about what’s available from Kitware’s C# VTK. If you’re doing it without extending the interactor style, it is best to listen to the interactor for events and then forward the event to the interactor style.

Here’s an example in C++, it should apply to Python and C# assuming VTK C# exposes the enums from vtkCommand and functions from interactor style.

void OnLeftButtonDown(....)
{
   // ...
   // switch style could be a special case, so just to be safe, let's handle it.
   auto* style = vtkInteractorStyle::SafeDownCast(interactor->GetInteractorStyle());
   if (auto* switchableStyle = vtkInteractorStyleSwitch::SafeDownCast(style))
   {
      switchableStyle->GetCurrentStyle()->OnLeftButtonDown();
   }
   else
   {
      style->OnLeftButtonDown();
   }
}

void OnLeftButtonUp(....)
{
   // ...
   // switch style could be a special case, so just to be safe, let's handle it.
   auto* style = vtkInteractorStyle::SafeDownCast(interactor->GetInteractorStyle());
   if (auto* switchableStyle = vtkInteractorStyleSwitch::SafeDownCast(style))
   {
      switchableStyle->GetCurrentStyle()->OnLeftButtonUp();
   }
   else
   {
      style->OnLeftButtonUp();
   }
}
interactor->AddObserver(vtkCommand::LeftButtonPressEvent, OnLeftButtonDown);
interactor->AddObserver(vtkCommand::LeftButtonReleaseEvent, OnLeftButtonUp);