KeypressEvents

#include <vtkActor.h>
#include <vtkInteractorStyleTrackballCamera.h>
#include <vtkNamedColors.h>
#include <vtkNew.h>
#include <vtkPolyDataMapper.h>
#include <vtkProperty.h>
#include <vtkRenderWindow.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkRenderer.h>
#include <vtkSphereSource.h>

namespace {

// Define interaction style.
class KeyPressInteractorStyle : public vtkInteractorStyleTrackballCamera
{
public:
  static KeyPressInteractorStyle* New();
  vtkTypeMacro(KeyPressInteractorStyle, vtkInteractorStyleTrackballCamera);

  virtual void OnKeyPress() override
  {
    // Get the keypress.
    vtkRenderWindowInteractor* rwi = this->Interactor;
    std::string key = rwi->GetKeySym();

    // Output the key that was pressed.
    std::cout << "Pressed " << key << std::endl;

    // Handle an arrow key.
    if (key == "Up")
    {
      std::cout << "The up arrow was pressed." << std::endl;
    }

    // Handle a "normal" key.
    if (key == "a")
    {
      std::cout << "The a key was pressed." << std::endl;
    }

    // Forward events.
    vtkInteractorStyleTrackballCamera::OnKeyPress();
  }
};
vtkStandardNewMacro(KeyPressInteractorStyle);

} // namespace

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

  vtkNew<vtkSphereSource> sphereSource;
  sphereSource->SetCenter(0.0, 0.0, 0.0);
  sphereSource->SetRadius(5.0);
  sphereSource->Update();

  vtkNew<vtkPolyDataMapper> mapper;
  mapper->SetInputConnection(sphereSource->GetOutputPort());

  // Create an actor
  vtkNew<vtkActor> actor;
  actor->SetMapper(mapper);
  actor->GetProperty()->SetColor(colors->GetColor3d("MistyRose").GetData());

  // A renderer and render window.
  vtkNew<vtkRenderer> renderer;
  vtkNew<vtkRenderWindow> renderWindow;
  renderWindow->AddRenderer(renderer);
  renderWindow->SetWindowName("KeypressEvents");

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

  vtkNew<KeyPressInteractorStyle> style;
  renderWindowInteractor->SetInteractorStyle(style);
  style->SetCurrentRenderer(renderer);

  renderer->AddActor(actor);
  renderer->SetBackground(colors->GetColor3d("SlateGray").GetData());

  renderWindow->Render();

  renderWindowInteractor->Start();

  return EXIT_SUCCESS;
}

cmake_minimum_required(VERSION 3.12 FATAL_ERROR)

project(KeypressEvents)

find_package(VTK COMPONENTS 
)

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

cd KeypressEvents/build

cmake ..

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

make

./KeypressEvents