# HighlightSelectedPoints

VTKExamples/Cxx/Picking/HighlightSelectedPoints

### Description

This example demonstrates how to select and highlight points using a rubber band. Press 'r' to enter selection mode. Selected points are shown in red. The ids of the selected points are output.

### Code

HighlightSelectedPoints.cxx

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

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

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

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

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

          vtkSmartPointer<vtkExtractGeometry> extractGeometry =
            vtkSmartPointer<vtkExtractGeometry>::New();
          extractGeometry->SetImplicitFunction(frustum);
          extractGeometry->SetInputData(this->Points);
          extractGeometry->Update();

          vtkSmartPointer<vtkVertexGlyphFilter> glyphFilter =
            vtkSmartPointer<vtkVertexGlyphFilter>::New();
          glyphFilter->SetInputConnection(extractGeometry->GetOutputPort());
          glyphFilter->Update();

          vtkPolyData* selected = glyphFilter->GetOutput();
          std::cout << "Selected " << selected->GetNumberOfPoints() << " points." << std::endl;
          std::cout << "Selected " << selected->GetNumberOfCells() << " cells." << std::endl;
          this->SelectedMapper->SetInputData(selected);
          this->SelectedMapper->ScalarVisibilityOff();

          vtkIdTypeArray* ids = vtkIdTypeArray::SafeDownCast(selected->GetPointData()->GetArray("OriginalIds"));
          for(vtkIdType i = 0; i < ids->GetNumberOfTuples(); i++)
          {
            std::cout << "Id " << i << " : " << ids->GetValue(i) << std::endl;
          }

          this->SelectedActor->GetProperty()->SetColor(1.0, 0.0, 0.0); //(R,G,B)
          this->SelectedActor->GetProperty()->SetPointSize(3);

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

        void SetPoints(vtkSmartPointer<vtkPolyData> points) {this->Points = points;}
      private:
        vtkSmartPointer<vtkPolyData> Points;
        vtkSmartPointer<vtkActor> SelectedActor;
        vtkSmartPointer<vtkDataSetMapper> SelectedMapper;

    };
    vtkStandardNewMacro(InteractorStyle);

    int main (int, char *[])
    {
      vtkSmartPointer<vtkPointSource> pointSource =
        vtkSmartPointer<vtkPointSource>::New();
      pointSource->SetNumberOfPoints(20);
      pointSource->Update();

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

      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->SetInputData(input);
      mapper->ScalarVisibilityOff();

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

      // 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<InteractorStyle> style =
        vtkSmartPointer<InteractorStyle>::New();
      style->SetPoints(input);
      renderWindowInteractor->SetInteractorStyle( style );

      renderWindowInteractor->Start();

      return EXIT_SUCCESS;
    }

### CMakeLists.txt

    cmake_minimum_required(VERSION 2.8)

    PROJECT(HighlightSelectedPoints)

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

    add_executable(HighlightSelectedPoints MACOSX_BUNDLE HighlightSelectedPoints.cxx )

    target_link_libraries(HighlightSelectedPoints ${VTK_LIBRARIES})

### Download and Build HighlightSelectedPoints

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

    cd HighlightSelectedPoints/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:

    ./HighlightSelectedPoints

WINDOWS USERS

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