# VisualizeGraph

VTKExamples/Cxx/Graphs/VisualizeGraph

### Description

This example shows how to construct a graph and visualize it. You can select edges and vertices with the mouse.

Other Languages

See (Python), (Java)

### Code

VisualizeGraph.cxx

    #include <vtkSmartPointer.h>

    #include <vtkGraphLayoutStrategy.h>
    #include <vtkGraphLayoutView.h>
    #include <vtkGraphWriter.h>
    #include <vtkMutableUndirectedGraph.h>
    #include <vtkRenderWindowInteractor.h>
    #include <vtkSimple2DLayoutStrategy.h>

    int main(int, char *[])
    {
      vtkSmartPointer<vtkMutableUndirectedGraph> g =
        vtkSmartPointer<vtkMutableUndirectedGraph>::New();

      vtkIdType v1 = g->AddVertex();
      vtkIdType v2 = g->AddVertex();

      g->AddEdge(v1, v2);
      g->AddEdge(v1, v2);

      vtkSmartPointer<vtkGraphLayoutView> graphLayoutView =
        vtkSmartPointer<vtkGraphLayoutView>::New();
      graphLayoutView->AddRepresentationFromInput(g);
      graphLayoutView->SetLayoutStrategy("Simple 2D");
      graphLayoutView->ResetCamera();
      graphLayoutView->Render();

      vtkSimple2DLayoutStrategy::SafeDownCast(graphLayoutView->GetLayoutStrategy())->SetRandomSeed(0);
      graphLayoutView->GetInteractor()->Start();

      return EXIT_SUCCESS;
    }

### CMakeLists.txt

    cmake_minimum_required(VERSION 3.3 FATAL_ERROR)

    project(VisualizeGraph)

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

### Download and Build VisualizeGraph

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

    cd VisualizeGraph/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:

    ./VisualizeGraph

WINDOWS USERS

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