SphereWidgetEvents

#include <vtkCallbackCommand.h>
#include <vtkCommand.h>
#include <vtkNamedColors.h>
#include <vtkNew.h>
#include <vtkProperty.h>
#include <vtkRenderWindow.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkRenderer.h>
#include <vtkSmartPointer.h>
#include <vtkSphereWidget.h>

#include <iostream>
#include <string>

namespace {

class MySphereWidget : public vtkSphereWidget
{
public:
  static MySphereWidget* New();
  vtkTypeMacro(MySphereWidget, vtkSphereWidget);

  // Handles the events
  static void ProcessEvents(vtkObject* object, unsigned long event,
                            void* clientdata, void* calldata);

protected:
  MySphereWidget();

  // Create a new callback command rather than using the one defined in
  // vtkSphereWidget. This prevents problems with unexpected behavior due
  // to the AbortFlag being manipulated.
  vtkSmartPointer<vtkCallbackCommand> MyEventCallbackCommand;
};

MySphereWidget::MySphereWidget()
{

  this->MyEventCallbackCommand = vtkSmartPointer<vtkCallbackCommand>::New();

  // Connect our own callback command to our own ProcessEvents function.
  // This way we do not have to deal with side effects of
  // SphereWidget::ProcessEvents.
  this->MyEventCallbackCommand->SetCallback(MySphereWidget::ProcessEvents);

  // Connect our callback function to a few events.
  this->AddObserver(vtkCommand::StartInteractionEvent,
                    this->MyEventCallbackCommand);

  this->AddObserver(vtkCommand::InteractionEvent, this->MyEventCallbackCommand);

  this->AddObserver(vtkCommand::EndInteractionEvent,
                    this->MyEventCallbackCommand);
}

void MySphereWidget::ProcessEvents(vtkObject* vtkNotUsed(object),
                                   unsigned long event,
                                   void* vtkNotUsed(clientdata),
                                   void* vtkNotUsed(calldata))
{
  switch (event)
  {
  case vtkCommand::StartInteractionEvent:
    std::cout << "StartInteractionEvent" << std::endl;
    break;
  case vtkCommand::EndInteractionEvent:
    std::cout << "EndInteractionEvent" << std::endl;
    break;
  case vtkCommand::InteractionEvent:
    std::cout << "InteractionEvent" << std::endl;
    break;
  }
}

vtkStandardNewMacro(MySphereWidget);
} // namespace

int main(int, char*[])
{
  vtkNew<vtkNamedColors> colors;

  // Create  a renderer and render window.
  vtkNew<vtkRenderer> renderer;
  renderer->SetBackground(colors->GetColor3d("MidnightBlue").GetData());

  vtkNew<vtkRenderWindow> renderWindow;
  renderWindow->AddRenderer(renderer);
  renderWindow->SetWindowName("SphereWidgetEvents");

  // Create an interactor.
  vtkNew<vtkRenderWindowInteractor> renderWindowInteractor;
  renderWindowInteractor->SetRenderWindow(renderWindow);

  vtkNew<MySphereWidget> sphereWidget;
  sphereWidget->SetInteractor(renderWindowInteractor);
  sphereWidget->SetRepresentationToSurface();
  sphereWidget->HandleVisibilityOn();

  renderWindow->Render();
  renderWindowInteractor->Initialize();
  renderWindow->Render();
  sphereWidget->On();
  renderWindowInteractor->Start();

  return EXIT_SUCCESS;
}

cmake_minimum_required(VERSION 3.12 FATAL_ERROR)

project(SphereWidgetEvents)

find_package(VTK COMPONENTS 
)

if (NOT VTK_FOUND)
  message(FATAL_ERROR "SphereWidgetEvents: Unable to find the VTK build folder.")
endif()

# Prevent a "command line is too long" failure in Windows.
set(CMAKE_NINJA_FORCE_RESPONSE_FILE "ON" CACHE BOOL "Force Ninja to use response files.")
add_executable(SphereWidgetEvents MACOSX_BUNDLE SphereWidgetEvents.cxx )
  target_link_libraries(SphereWidgetEvents PRIVATE ${VTK_LIBRARIES}
)
# vtk_module_autoinit is needed
vtk_module_autoinit(
  TARGETS SphereWidgetEvents
  MODULES ${VTK_LIBRARIES}
)

cd SphereWidgetEvents/build

cmake ..

cmake -DVTK_DIR:PATH=/home/me/vtk_build ..

make

./SphereWidgetEvents