# ColorVerticesLookupTable

VTKExamples/Cxx/Graphs/ColorVerticesLookupTable

### Code

ColorVerticesLookupTable.cxx

    #include <vtkSmartPointer.h>
    #include <vtkPoints.h>
    #include <vtkDataSetAttributes.h>
    #include <vtkGraphLayoutView.h>
    #include <vtkIntArray.h>
    #include <vtkLookupTable.h>
    #include <vtkMutableDirectedGraph.h>
    #include <vtkRenderWindow.h>
    #include <vtkRenderWindowInteractor.h>
    #include <vtkViewTheme.h>
    #include <vtkRenderer.h>
    #include <vtkCamera.h>

    int main(int, char *[])
    {
      // Create a graph
      vtkSmartPointer<vtkMutableDirectedGraph> graph =
        vtkSmartPointer<vtkMutableDirectedGraph>::New();

      vtkIdType v1 = graph->AddVertex();
      vtkIdType v2 = graph->AddVertex();
      vtkIdType v3 = graph->AddVertex();
      graph->AddEdge(v1,v2);
      graph->AddEdge(v2,v3);

      // Manually set the position of the vertices
      vtkSmartPointer<vtkPoints> points =
        vtkSmartPointer<vtkPoints>::New();
      points->InsertNextPoint(0,0,0);
      points->InsertNextPoint(1,0,0);
      points->InsertNextPoint(2,0,0);

      graph->SetPoints(points);

      // Create the color array
      vtkSmartPointer<vtkIntArray> vertexColors =
        vtkSmartPointer<vtkIntArray>::New();
      vertexColors->SetNumberOfComponents(1);
      vertexColors->SetName("Color");

      vtkSmartPointer<vtkLookupTable> lookupTable =
        vtkSmartPointer<vtkLookupTable>::New();
      lookupTable->SetNumberOfTableValues(3);
      lookupTable->SetTableValue(0, 1.0, 0.0, 0.0); // red
      lookupTable->SetTableValue(1, 1.0, 1.0, 1.0); // white
      lookupTable->SetTableValue(2, 0.0, 1.0, 0.0); // green
      lookupTable->Build();

      vertexColors->InsertNextValue(0);
      vertexColors->InsertNextValue(1);
      vertexColors->InsertNextValue(2);

      // Add the color array to the graph
      graph->GetVertexData()->AddArray(vertexColors);

      // Visualize
      vtkSmartPointer<vtkGraphLayoutView> graphLayoutView =
        vtkSmartPointer<vtkGraphLayoutView>::New();
      graphLayoutView->AddRepresentationFromInput(graph);
      graphLayoutView->SetLayoutStrategyToPassThrough();
      graphLayoutView->SetVertexColorArrayName("Color");
      graphLayoutView->ColorVerticesOn();

      vtkSmartPointer<vtkViewTheme> theme =
        vtkSmartPointer<vtkViewTheme>::New();
      theme->SetPointLookupTable(lookupTable);

      graphLayoutView->ApplyViewTheme(theme);
      graphLayoutView->ResetCamera();
      graphLayoutView->GetInteractor()->Initialize();
      graphLayoutView->GetRenderer()->GetActiveCamera()->Zoom(0.8);
      graphLayoutView->GetInteractor()->Start();

      return EXIT_SUCCESS;
    }

### CMakeLists.txt

    cmake_minimum_required(VERSION 2.8)

    PROJECT(ColorVerticesLookupTable)

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

    add_executable(ColorVerticesLookupTable MACOSX_BUNDLE ColorVerticesLookupTable.cxx)

    target_link_libraries(ColorVerticesLookupTable ${VTK_LIBRARIES})

### Download and Build ColorVerticesLookupTable

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

    cd ColorVerticesLookupTable/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:

    ./ColorVerticesLookupTable

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.