[vtkusers] VtkSphereWidget unable to handle the right or left click...

[Dean Inglis]

Hi David,

>I believe it is because that event is simply not handled by the widget. If
>you look here:
>http://www.vtk.org/doc/nightly/html/classvtkSphereWidget.html#_details
>
>You will see InteractionEvent, but not LeftButton*
>
>I tried to subclass the sphere widget and catch the event:
>http://www.vtk.org/Wiki/VTK/Examples/Widgets/SphereWidgetEvents
>
>but it didn't work. Anyone know why?

this is because in the parent class, the constructor sets a specific static
(non-virtual) method:

vtkSphereWidget::vtkSphereWidget()
{
  this->State = vtkSphereWidget::Start;
  this->EventCallbackCommand->SetCallback(vtkSphereWidget::ProcessEvents);

MySphereWidget would need to implement the static method ProcessEvents:

void MySphereWidget::ProcessEvents(vtkObject* vtkNotUsed(object), 
                                    unsigned long event,
                                    void* clientdata, 
                                    void* vtkNotUsed(calldata))
{
  MySphereWidget* self = reinterpret_cast<MySphereWidget *>( clientdata );

and implement the constructor:

MySphereWidget::MySphereWidget()
{
  this->EventCallbackCommand->SetCallback(MySphereWidget::ProcessEvents);
}

Dean