SeedWidgetImage

#include <vtkActor.h>
#include <vtkCommand.h>
#include <vtkImageActor.h>
#include <vtkImageCanvasSource2D.h>
#include <vtkInteractorStyleImage.h>
#include <vtkPointHandleRepresentation2D.h>
#include <vtkPolyDataMapper.h>
#include <vtkProperty2D.h>
#include <vtkRenderer.h>
#include <vtkRenderWindow.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkSeedWidget.h>
#include <vtkSeedRepresentation.h>
#include <vtkSmartPointer.h>
#include <vtkSphereSource.h>

class vtkSeedImageCallback : public vtkCommand
{
  public:
    static vtkSeedImageCallback *New()
    {
      return new vtkSeedImageCallback;
    }

    vtkSeedImageCallback() {}

    virtual void Execute(vtkObject*, unsigned long event, void *calldata)
    {
      if (event == vtkCommand::PlacePointEvent)
        {
    std::cout << "Placing point..." << std::endl;
    std::cout << "There are now " << this->SeedRepresentation->GetNumberOfSeeds() << " seeds." << std::endl;
    for(unsigned int seedId = 0; static_cast<int>(seedId) < this->SeedRepresentation->GetNumberOfSeeds(); seedId++)
      {
      double pos[3];
      this->SeedRepresentation->GetSeedDisplayPosition(seedId, pos);
      std::cout << "Seed " << seedId << " : (" << pos[0] << " " << pos[1] << " " << pos[2] << ")" << std::endl;
      }
    return;
        }
      if (event == vtkCommand::InteractionEvent)
        {
    std::cout << "Interaction..." << std::endl;
        if (calldata)
          {
      double pos[3];
      this->SeedRepresentation->GetSeedDisplayPosition(0, pos);
      std::cout << "Moved to (" << pos[0] << " " << pos[1] << " " << pos[2] << ")" << std::endl;
          }
    return;
        }
    }

    void SetRepresentation(vtkSmartPointer<vtkSeedRepresentation> rep)
    {
      this->SeedRepresentation = rep;
    }
    void SetWidget(vtkSmartPointer<vtkSeedWidget> widget)
    {
      this->SeedWidget = widget;
    }

  private:
    vtkSeedRepresentation* SeedRepresentation;
    vtkSeedWidget* SeedWidget;
};

int main(int /* argc */, char * /* argv */ [])
{
  // Create an image
  vtkSmartPointer<vtkImageCanvasSource2D> drawing =
    vtkSmartPointer<vtkImageCanvasSource2D>::New();
  drawing->SetScalarTypeToUnsignedChar();
  drawing->SetNumberOfScalarComponents(3);
  drawing->SetExtent(0, 20, 0, 50, 0, 0);
  // Make a blue background
  drawing->SetDrawColor(0, 0, 255);
  drawing->FillBox(0,20,0,50);
  // Make a red circle
  drawing->SetDrawColor(255, 0, 0, 0);
  drawing->DrawCircle(9, 10, 5);
  drawing->Update();

  vtkSmartPointer<vtkImageActor> imageActor =
    vtkSmartPointer<vtkImageActor>::New();
  imageActor->SetInputData(drawing->GetOutput());

  // Create a renderer and render window
  vtkSmartPointer<vtkRenderer> renderer =
    vtkSmartPointer<vtkRenderer>::New();
  renderer->AddActor(imageActor);
  vtkSmartPointer<vtkRenderWindow> renderWindow =
    vtkSmartPointer<vtkRenderWindow>::New();
  renderWindow->AddRenderer(renderer);

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

  // Setup interactor style
  vtkSmartPointer<vtkInteractorStyleImage> interactorStyleImage =
    vtkSmartPointer<vtkInteractorStyleImage>::New();
  renderWindowInteractor->SetInteractorStyle(interactorStyleImage);

  // Create the representation
  vtkSmartPointer<vtkPointHandleRepresentation2D> handle =
    vtkSmartPointer<vtkPointHandleRepresentation2D>::New();
  handle->GetProperty()->SetColor(1,0,0);
  vtkSmartPointer<vtkSeedRepresentation> rep =
    vtkSmartPointer<vtkSeedRepresentation>::New();
  rep->SetHandleRepresentation(handle);

  // Seed widget
  vtkSmartPointer<vtkSeedWidget> seedWidget =
    vtkSmartPointer<vtkSeedWidget>::New();
  seedWidget->SetInteractor(renderWindowInteractor);
  seedWidget->SetRepresentation(rep);

  vtkSmartPointer<vtkSeedImageCallback> seedCallback =
    vtkSmartPointer<vtkSeedImageCallback>::New();
  seedCallback->SetRepresentation(rep);
  seedCallback->SetWidget(seedWidget);
  seedWidget->AddObserver(vtkCommand::PlacePointEvent,seedCallback);
  seedWidget->AddObserver(vtkCommand::InteractionEvent,seedCallback);

  renderWindow->Render();

  renderWindowInteractor->Initialize();
  renderWindow->Render();
  seedWidget->On();

  renderWindowInteractor->Start();

  return EXIT_SUCCESS;
}

cmake_minimum_required(VERSION 3.3 FATAL_ERROR)

project(SeedWidgetImage)

find_package(VTK COMPONENTS 
  vtkCommonCore
  vtkFiltersSources
  vtkImagingSources
  vtkInteractionStyle
  vtkInteractionWidgets
  vtkRenderingCore
  vtkRenderingFreeType
  vtkRenderingOpenGL2 QUIET)
if (NOT VTK_FOUND)
  message("Skipping SeedWidgetImage: ${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(SeedWidgetImage MACOSX_BUNDLE SeedWidgetImage.cxx )
  target_link_libraries(SeedWidgetImage PRIVATE ${VTK_LIBRARIES})
else ()
  # include all components
  add_executable(SeedWidgetImage MACOSX_BUNDLE SeedWidgetImage.cxx )
  target_link_libraries(SeedWidgetImage PRIVATE ${VTK_LIBRARIES})
  # vtk_module_autoinit is needed
  vtk_module_autoinit(
    TARGETS SeedWidgetImage
    MODULES ${VTK_LIBRARIES}
    )
endif () 

cd SeedWidgetImage/build 

cmake ..

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

make

./SeedWidgetImage