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# SeedWidgetImage

VTKEx/Cxx/Widgets/SeedWidgetImage

Question

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### Code

SeedWidgetImage.cxx

    #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 <vtkRenderWindow.h>
    #include <vtkRenderWindowInteractor.h>
    #include <vtkRenderer.h>
    #include <vtkSeedRepresentation.h>
    #include <vtkSeedWidget.h>
    #include <vtkSmartPointer.h>
    #include <vtkSphereSource.h>

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

      vtkSeedImageCallback() = default;

      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 = nullptr;
      vtkSeedWidget* SeedWidget = nullptr;
    };

    int main(int /* argc */, char* /* argv */[])
    {
      // Create an image
      auto 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();

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

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

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

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

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

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

      auto 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;
    }

### CMakeLists.txt

    cmake_minimum_required(VERSION 3.3 FATAL_ERROR)

    project(SeedWidgetImage)

    find_package(VTK COMPONENTS
      vtkvtkCommonCore
      vtkvtkFiltersSources
      vtkvtkImagingSources
      vtkvtkInteractionStyle
      vtkvtkInteractionWidgets
      vtkvtkRenderingContextOpenGL2
      vtkvtkRenderingCore
      vtkvtkRenderingFreeType
      vtkvtkRenderingGL2PSOpenGL2
      vtkvtkRenderingOpenGL2 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 ()

### Download and Build SeedWidgetImage

Click here to download SeedWidgetImage and its CMakeLists.txt file. Once the tarball SeedWidgetImage.tar has been downloaded and extracted,

    cd SeedWidgetImage/build

If VTK is installed:

    cmake ..

If VTK is not installed but compiled on your system, you will need to specify the path to your VTK build:

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

Build the project:

    make

and run it:

    ./SeedWidgetImage

WINDOWS USERS

Be sure to add the VTK bin directory to your path. This will resolve the VTK dll's at run time.