RubberBand2DObserver

#include <vtkSmartPointer.h>
#include <vtkPolyDataMapper.h>
#include <vtkActor.h>
#include <vtkRenderWindow.h>
#include <vtkRenderer.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkPolyData.h>
#include <vtkSphereSource.h>
#include <vtkInteractorStyleRubberBand2D.h>
#include <vtkCallbackCommand.h>

void SelectionChangedCallbackFunction( vtkObject* caller, 
  long unsigned int eventId, void* clientData, void* callData );

int main(int, char *[])
{
  vtkSmartPointer<vtkSphereSource> sphereSource = 
    vtkSmartPointer<vtkSphereSource>::New();

  // Create a mapper and actor
  vtkSmartPointer<vtkPolyDataMapper> mapper = 
    vtkSmartPointer<vtkPolyDataMapper>::New();
  mapper->SetInputConnection(sphereSource->GetOutputPort());

  vtkSmartPointer<vtkActor> actor = 
    vtkSmartPointer<vtkActor>::New();
  actor->SetMapper(mapper);

  // A renderer and render window
  vtkSmartPointer<vtkRenderer> renderer = 
    vtkSmartPointer<vtkRenderer>::New();
  vtkSmartPointer<vtkRenderWindow> renderWindow = 
    vtkSmartPointer<vtkRenderWindow>::New();
  renderWindow->AddRenderer(renderer);

  // An interactor
  vtkSmartPointer<vtkRenderWindowInteractor> renderWindowInteractor = 
    vtkSmartPointer<vtkRenderWindowInteractor>::New();
  renderWindowInteractor->SetRenderWindow(renderWindow);

  // Add the actors to the scene
  renderer->AddActor(actor);
  renderer->SetBackground(1,1,1); // Background color white
  renderWindow->Render();

  vtkSmartPointer<vtkCallbackCommand> selectionChangedCallback = 
    vtkSmartPointer<vtkCallbackCommand>::New();
  selectionChangedCallback->SetCallback ( SelectionChangedCallbackFunction );

  vtkSmartPointer<vtkInteractorStyleRubberBand2D> style = 
    vtkSmartPointer<vtkInteractorStyleRubberBand2D>::New();
  style->AddObserver ( vtkCommand::SelectionChangedEvent, selectionChangedCallback );
  renderWindowInteractor->SetInteractorStyle( style );

  // Begin mouse interaction
  renderWindowInteractor->Start();

  return EXIT_SUCCESS;
}


void SelectionChangedCallbackFunction ( vtkObject* vtkNotUsed(caller), 
  long unsigned int vtkNotUsed(eventId), void* vtkNotUsed(clientData), void* callData )
{
  std::cout << "SelectionChanged callback" << std::endl;

  unsigned int* rect = reinterpret_cast<unsigned int*> ( callData );
  unsigned int pos1X = rect[0];
  unsigned int pos1Y = rect[1];
  unsigned int pos2X = rect[2];
  unsigned int pos2Y = rect[3];

  std::cout << "Start x: " << pos1X << " Start y: " << pos1Y 
            << " End x: " << pos2X << " End y: " << pos2Y << std::endl;
}

cmake_minimum_required(VERSION 3.3 FATAL_ERROR)

project(RubberBand2DObserver)

find_package(VTK COMPONENTS 
  vtkvtkCommonCore
  vtkvtkCommonDataModel
  vtkvtkFiltersSources
  vtkvtkInteractionStyle
  vtkvtkRenderingContextOpenGL2
  vtkvtkRenderingCore
  vtkvtkRenderingFreeType
  vtkvtkRenderingGL2PSOpenGL2
  vtkvtkRenderingOpenGL2 QUIET)
if (NOT VTK_FOUND)
  message("Skipping RubberBand2DObserver: ${VTK_NOT_FOUND_MESSAGE}")
  return ()
endif()
message (STATUS "VTK_VERSION: ${VTK_VERSION}")
if (VTK_VERSION VERSION_LESS "8.90.0")
  # old system
  include(${VTK_USE_FILE})
  add_executable(RubberBand2DObserver MACOSX_BUNDLE RubberBand2DObserver.cxx )
  target_link_libraries(RubberBand2DObserver PRIVATE ${VTK_LIBRARIES})
else ()
  # include all components
  add_executable(RubberBand2DObserver MACOSX_BUNDLE RubberBand2DObserver.cxx )
  target_link_libraries(RubberBand2DObserver PRIVATE ${VTK_LIBRARIES})
  # vtk_module_autoinit is needed
  vtk_module_autoinit(
    TARGETS RubberBand2DObserver
    MODULES ${VTK_LIBRARIES}
    )
endif ()

cd RubberBand2DObserver/build

cmake ..

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

make

./RubberBand2DObserver