SphereWidget

#include <vtkCallbackCommand.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 SphereCallback : public vtkCallbackCommand
{
public:
  static SphereCallback* New()
  {
    return new SphereCallback;
  }
  SphereCallback()
  {
  }

  virtual void Execute(vtkObject* caller, unsigned long, void*)
  {

    vtkSphereWidget* sphereWidget = reinterpret_cast<vtkSphereWidget*>(caller);

    double center[3];
    sphereWidget->GetCenter(center);
    std::cout << "Center: " << center[0] << " " << center[1] << " " << center[2]
              << std::endl;
  }
};
} // namespace

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

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

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

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

  vtkNew<vtkSphereWidget> sphereWidget;
  sphereWidget->SetInteractor(renderWindowInteractor);
  sphereWidget->SetRepresentationToSurface();
  sphereWidget->GetSphereProperty()->SetColor(
      colors->GetColor3d("BurlyWood").GetData());

  vtkNew<SphereCallback> sphereCallback;

  sphereWidget->AddObserver(vtkCommand::InteractionEvent, sphereCallback);

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

  return EXIT_SUCCESS;
}

cmake_minimum_required(VERSION 3.12 FATAL_ERROR)

project(SphereWidget)

find_package(VTK COMPONENTS 
  CommonColor
  CommonCore
  InteractionStyle
  InteractionWidgets
  RenderingContextOpenGL2
  RenderingCore
  RenderingFreeType
  RenderingGL2PSOpenGL2
  RenderingOpenGL2
)

if (NOT VTK_FOUND)
  message(FATAL_ERROR "SphereWidget: 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(SphereWidget MACOSX_BUNDLE SphereWidget.cxx )
  target_link_libraries(SphereWidget PRIVATE ${VTK_LIBRARIES}
)
# vtk_module_autoinit is needed
vtk_module_autoinit(
  TARGETS SphereWidget
  MODULES ${VTK_LIBRARIES}
)

cd SphereWidget/build

cmake ..

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

make

./SphereWidget