# HighlightSelection

VTKExamples/Cxx/Picking/HighlightSelection

### Description

This example demonstrates how to select and highlight cells using a rubber band. Press 'r' to enter selection mode.

### Code

HighlightSelection.cxx

    #include <vtkVersion.h>

    #include <vtkActor.h>
    #include <vtkAreaPicker.h>
    #include <vtkDataSetMapper.h>
    #include <vtkDataSetSurfaceFilter.h>
    #include <vtkExtractPolyDataGeometry.h>
    #include <vtkIdFilter.h>
    #include <vtkIdTypeArray.h>
    #include <vtkInteractorStyleRubberBandPick.h>
    #include <vtkObjectFactory.h>
    #include <vtkPlanes.h>
    #include <vtkPointData.h>
    #include <vtkPolyData.h>
    #include <vtkPolyDataMapper.h>
    #include <vtkProperty.h>
    #include <vtkRenderer.h>
    #include <vtkRendererCollection.h>
    #include <vtkRenderWindow.h>
    #include <vtkRenderWindowInteractor.h>
    #include <vtkSmartPointer.h>
    #include <vtkSphereSource.h>
    #include <vtkUnstructuredGrid.h>
    #include <vtkVersion.h>
    #include <vtkVertexGlyphFilter.h>

    #define VTKISRBP_ORIENT 0
    #define VTKISRBP_SELECT 1

    // Define interaction style
    class HighlightInteractorStyle : public vtkInteractorStyleRubberBandPick
    {
      public:
        static HighlightInteractorStyle* New();
        vtkTypeMacro(HighlightInteractorStyle,vtkInteractorStyleRubberBandPick);

        HighlightInteractorStyle() : vtkInteractorStyleRubberBandPick()
        {
          this->SelectedMapper = vtkSmartPointer<vtkDataSetMapper>::New();
          this->SelectedActor = vtkSmartPointer<vtkActor>::New();
          this->SelectedActor->SetMapper(SelectedMapper);
        }

        virtual void OnLeftButtonUp()
        {
          // Forward events
          vtkInteractorStyleRubberBandPick::OnLeftButtonUp();

          if(this->CurrentMode == VTKISRBP_SELECT)
          {
            vtkPlanes* frustum = static_cast<vtkAreaPicker*>(this->GetInteractor()->GetPicker())->GetFrustum();

            vtkSmartPointer<vtkExtractPolyDataGeometry> extractPolyDataGeometry =
              vtkSmartPointer<vtkExtractPolyDataGeometry>::New();
    #if VTK_MAJOR_VERSION <= 5
            extractPolyDataGeometry->SetInput(this->PolyData);
    #else
            extractPolyDataGeometry->SetInputData(this->PolyData);
    #endif
            extractPolyDataGeometry->SetImplicitFunction(frustum);
            extractPolyDataGeometry->Update();

            std::cout << "Extracted " << extractPolyDataGeometry->GetOutput()->GetNumberOfCells() << " cells." << std::endl;

    #if VTK_MAJOR_VERSION <= 5
            this->SelectedMapper->SetInputConnection(
              extractPolyDataGeometry->GetOutputPort());
    #else
            this->SelectedMapper->SetInputData(extractPolyDataGeometry->GetOutput());
    #endif
            this->SelectedMapper->ScalarVisibilityOff();

    //        vtkIdTypeArray* ids = vtkIdTypeArray::SafeDownCast(selected->GetPointData()->GetArray("OriginalIds"));

            this->SelectedActor->GetProperty()->SetColor(1.0, 0.0, 0.0); //(R,G,B)
            this->SelectedActor->GetProperty()->SetPointSize(5);

            this->GetInteractor()->GetRenderWindow()->GetRenderers()->GetFirstRenderer()->AddActor(SelectedActor);
            this->GetInteractor()->GetRenderWindow()->Render();
            this->HighlightProp(NULL);
          }
        }

        void SetPolyData(vtkSmartPointer<vtkPolyData> polyData) {this->PolyData = polyData;}
      private:
        vtkSmartPointer<vtkPolyData> PolyData;
        vtkSmartPointer<vtkActor> SelectedActor;
        vtkSmartPointer<vtkDataSetMapper> SelectedMapper;

    };
    vtkStandardNewMacro(HighlightInteractorStyle);

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

      vtkSmartPointer<vtkIdFilter> idFilter =
        vtkSmartPointer<vtkIdFilter>::New();
      idFilter->SetInputConnection(sphereSource->GetOutputPort());
      idFilter->SetIdsArrayName("OriginalIds");
      idFilter->Update();

      // This is needed to convert the ouput of vtkIdFilter (vtkDataSet) back to vtkPolyData
      vtkSmartPointer<vtkDataSetSurfaceFilter> surfaceFilter =
        vtkSmartPointer<vtkDataSetSurfaceFilter>::New();
      surfaceFilter->SetInputConnection(idFilter->GetOutputPort());
      surfaceFilter->Update();

      vtkPolyData* input = surfaceFilter->GetOutput();

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

      vtkSmartPointer<vtkActor> actor = vtkSmartPointer<vtkActor>::New();
      actor->SetMapper(mapper);
      actor->GetProperty()->SetPointSize(5);

      // Visualize
      vtkSmartPointer<vtkRenderer> renderer =
        vtkSmartPointer<vtkRenderer>::New();
      vtkSmartPointer<vtkRenderWindow> renderWindow =
        vtkSmartPointer<vtkRenderWindow>::New();
      renderWindow->AddRenderer(renderer);

      vtkSmartPointer<vtkAreaPicker> areaPicker =
        vtkSmartPointer<vtkAreaPicker>::New();
      vtkSmartPointer<vtkRenderWindowInteractor> renderWindowInteractor =
        vtkSmartPointer<vtkRenderWindowInteractor>::New();
      renderWindowInteractor->SetPicker(areaPicker);
      renderWindowInteractor->SetRenderWindow(renderWindow);

      renderer->AddActor(actor);
      //renderer->SetBackground(1,1,1); // Background color white

      renderWindow->Render();

      vtkSmartPointer<HighlightInteractorStyle> style =
        vtkSmartPointer<HighlightInteractorStyle>::New();
      style->SetPolyData(input);
      renderWindowInteractor->SetInteractorStyle( style );

      renderWindowInteractor->Start();

      return EXIT_SUCCESS;
    }

### CMakeLists.txt

    cmake_minimum_required(VERSION 2.8)

    PROJECT(HighlightSelection)

    find_package(VTK REQUIRED)
    include(${VTK_USE_FILE})

    add_executable(HighlightSelection MACOSX_BUNDLE HighlightSelection.cxx )

    target_link_libraries(HighlightSelection ${VTK_LIBRARIES})

### Download and Build HighlightSelection

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

    cd HighlightSelection/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:

    ./HighlightSelection

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