# ColorVertexLabels

VTKExamples/Cxx/Graphs/ColorVertexLabels

### Code

ColorVertexLabels.cxx

    #include <vtkSmartPointer.h>
    #include <vtkIntArray.h>
    #include <vtkDataSetAttributes.h>
    #include <vtkGraphLayoutView.h>
    #include <vtkMutableDirectedGraph.h>
    #include <vtkRenderWindowInteractor.h>
    #include <vtkRenderWindow.h>
    #include <vtkRenderedGraphRepresentation.h>
    #include <vtkTextProperty.h>

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

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

      // Create an array for the vertex labels
      vtkSmartPointer<vtkIntArray> vertexIDs =
        vtkSmartPointer<vtkIntArray>::New();
      vertexIDs->SetNumberOfComponents(1);
      vertexIDs->SetName("VertexIDs");

      // Set the vertex labels
      vertexIDs->InsertNextValue(0);
      vertexIDs->InsertNextValue(1);

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

      vtkSmartPointer<vtkGraphLayoutView> graphLayoutView =
        vtkSmartPointer<vtkGraphLayoutView>::New();
      graphLayoutView->AddRepresentationFromInput(graph);
      graphLayoutView->SetVertexLabelVisibility(true);
      vtkRenderedGraphRepresentation::SafeDownCast(graphLayoutView->GetRepresentation())
                ->GetVertexLabelTextProperty()->SetColor(1,0,0);
      graphLayoutView->SetLayoutStrategyToSimple2D();
      graphLayoutView->SetVertexLabelArrayName("VertexIDs");
      graphLayoutView->ResetCamera();
      graphLayoutView->Render();
      graphLayoutView->GetInteractor()->Start();

      return EXIT_SUCCESS;
    }

### CMakeLists.txt

    cmake_minimum_required(VERSION 3.3 FATAL_ERROR)

    project(ColorVertexLabels)

    find_package(VTK COMPONENTS
      vtkCommonCore
      vtkCommonDataModel
      vtkInteractionStyle
      vtkRenderingCore
      vtkRenderingFreeType
      vtkRenderingOpenGL2
      vtkViewsInfovis QUIET)
    if (NOT VTK_FOUND)
      message("Skipping ColorVertexLabels: ${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(ColorVertexLabels MACOSX_BUNDLE ColorVertexLabels.cxx )
      target_link_libraries(ColorVertexLabels PRIVATE ${VTK_LIBRARIES})
    else ()
      # include all components
      add_executable(ColorVertexLabels MACOSX_BUNDLE ColorVertexLabels.cxx )
      target_link_libraries(ColorVertexLabels PRIVATE ${VTK_LIBRARIES})
      # vtk_module_autoinit is needed
      vtk_module_autoinit(
        TARGETS ColorVertexLabels
        MODULES ${VTK_LIBRARIES}
        )
    endif ()

### Download and Build ColorVertexLabels

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

    cd ColorVertexLabels/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:

    ./ColorVertexLabels

WINDOWS USERS

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