# ColorDisconnectedRegions

VTKExamples/Cxx/PolyData/ColorDisconnectedRegions

### Code

ColorDisconnectedRegions.cxx

    #include <vtkSmartPointer.h>
    #include <vtkPointData.h>
    #include <vtkSphereSource.h>
    #include <vtkPolyDataConnectivityFilter.h>
    #include <vtkPolyDataMapper.h>
    #include <vtkActor.h>
    #include <vtkProperty.h>
    #include <vtkRenderer.h>
    #include <vtkRenderWindow.h>
    #include <vtkRenderWindowInteractor.h>
    #include <vtkAppendPolyData.h>

    int main(int, char*[])
    {
      // Create some spheres
      vtkSmartPointer<vtkSphereSource> sphereSource1 =
        vtkSmartPointer<vtkSphereSource>::New();
      sphereSource1->Update();

      vtkSmartPointer<vtkSphereSource> sphereSource2 =
        vtkSmartPointer<vtkSphereSource>::New();
      sphereSource2->SetCenter(5,0,0);
      sphereSource2->Update();

      vtkSmartPointer<vtkSphereSource> sphereSource3 =
        vtkSmartPointer<vtkSphereSource>::New();
      sphereSource3->SetCenter(10,0,0);
      sphereSource3->Update();

      vtkSmartPointer<vtkAppendPolyData> appendFilter =
        vtkSmartPointer<vtkAppendPolyData>::New();
      appendFilter->AddInputConnection(sphereSource1->GetOutputPort());
      appendFilter->AddInputConnection(sphereSource2->GetOutputPort());
      appendFilter->AddInputConnection(sphereSource3->GetOutputPort());
      appendFilter->Update();

      vtkSmartPointer<vtkPolyDataConnectivityFilter> connectivityFilter =
        vtkSmartPointer<vtkPolyDataConnectivityFilter>::New();
      connectivityFilter->SetInputConnection(appendFilter->GetOutputPort());
      connectivityFilter->SetExtractionModeToAllRegions();
      connectivityFilter->ColorRegionsOn();
      connectivityFilter->Update();

      // Visualize
      vtkSmartPointer<vtkPolyDataMapper> mapper =
        vtkSmartPointer<vtkPolyDataMapper>::New();
      mapper->SetInputConnection(connectivityFilter->GetOutputPort());
      mapper->SetScalarRange(connectivityFilter->GetOutput()->GetPointData()->GetArray("RegionId")->GetRange());
      mapper->Update();

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

      vtkSmartPointer<vtkRenderer> renderer =
        vtkSmartPointer<vtkRenderer>::New();
      renderer->AddActor(actor);

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

      vtkSmartPointer<vtkRenderWindowInteractor> interactor =
        vtkSmartPointer<vtkRenderWindowInteractor>::New();
      interactor->SetRenderWindow(renderWindow);
      interactor->Initialize();
      interactor->Start();

      return EXIT_SUCCESS;
    }

### CMakeLists.txt

    cmake_minimum_required(VERSION 2.8)

    PROJECT(ColorDisconnectedRegions)

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

    add_executable(ColorDisconnectedRegions MACOSX_BUNDLE ColorDisconnectedRegions.cxx )

    target_link_libraries(ColorDisconnectedRegions ${VTK_LIBRARIES})

### Download and Build ColorDisconnectedRegions

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

    cd ColorDisconnectedRegions/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:

    ./ColorDisconnectedRegions

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.