# ConstructTree

VTKExamples/Cxx/Graphs/ConstructTree

### Code

ConstructTree.cxx

    #include <vtkSmartPointer.h>

    #include <vtkGraphLayoutView.h>
    #include <vtkMutableDirectedGraph.h>
    #include <vtkRenderWindowInteractor.h>
    #include <vtkTree.h>

    int main (int, char *[] )
    {

      vtkSmartPointer<vtkMutableDirectedGraph> graph =
        vtkSmartPointer<vtkMutableDirectedGraph>::New();

      vtkIdType v1 = graph->AddVertex();
      vtkIdType v2 = graph->AddChild(v1);
      graph->AddChild(v1);
      graph->AddChild(v2);

      /*
      //equivalent to:

      vtkIdType V1 = g->AddVertex();
      vtkIdType V2 = g->AddVertex();
      vtkIdType V3 = g->AddVertex();
      vtkIdType V4 = g->AddVertex();

      g->AddEdge ( V1, V2 );
      g->AddEdge ( V1, V3 );
      g->AddEdge ( V2, V4 );
      */

      vtkSmartPointer<vtkTree> tree =
        vtkSmartPointer<vtkTree>::New();
      bool success = tree->CheckedShallowCopy(graph);
      std::cout << "Success? " << success << std::endl;

      vtkSmartPointer<vtkGraphLayoutView> treeLayoutView =
        vtkSmartPointer<vtkGraphLayoutView>::New();
      treeLayoutView->AddRepresentationFromInput(tree);
      treeLayoutView->SetLayoutStrategyToTree();
      treeLayoutView->ResetCamera();
      treeLayoutView->Render();
      treeLayoutView->GetInteractor()->Start();

      return EXIT_SUCCESS;
    }

### CMakeLists.txt

    cmake_minimum_required(VERSION 2.8)

    PROJECT(ConstructTree)

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

    add_executable(ConstructTree MACOSX_BUNDLE ConstructTree.cxx )

    target_link_libraries(ConstructTree ${VTK_LIBRARIES})

### Download and Build ConstructTree

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

    cd ConstructTree/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:

    ./ConstructTree

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.