# SelectedVerticesAndEdges

VTKExamples/Cxx/Graphs/SelectedVerticesAndEdges

### Description

- Thanks to Eric Monson

### Code

SelectedVerticesAndEdges.cxx

    #include <vtkSmartPointer.h>
    #include <vtkAnnotationLink.h>
    #include <vtkRenderedGraphRepresentation.h>
    #include <vtkRenderer.h>
    #include <vtkHardwareSelector.h>
    #include <vtkDoubleArray.h>
    #include <vtkSelectionNode.h>
    #include <vtkIdTypeArray.h>
    #include <vtkSelection.h>
    #include <vtkRenderWindow.h>
    #include <vtkUnsignedCharArray.h>
    #include <vtkObjectFactory.h>
    #include <vtkGraphLayoutStrategy.h>
    #include <vtkGraphLayoutView.h>
    #include <vtkGraphWriter.h>
    #include <vtkMutableUndirectedGraph.h>
    #include <vtkRenderWindowInteractor.h>
    #include <vtkSimple2DLayoutStrategy.h>
    #include <vtkInteractorStyleRubberBand2D.h>

    class RubberBandStyle : public vtkInteractorStyleRubberBand2D
    {
      public:
        static RubberBandStyle* New();
        vtkTypeMacro(RubberBandStyle, vtkInteractorStyleRubberBand2D);

      virtual void OnLeftButtonUp()
      {
        // Forward events
        vtkInteractorStyleRubberBand2D::OnLeftButtonUp();

        vtkSelection* selection = this->View->GetRepresentation()->GetAnnotationLink()->GetCurrentSelection();
        vtkSelectionNode* vertices;
        vtkSelectionNode* edges;
        if(selection->GetNode(0)->GetFieldType() == vtkSelectionNode::VERTEX)
        {
          vertices = selection->GetNode(0);
        }
        else if(selection->GetNode(0)->GetFieldType() == vtkSelectionNode::EDGE)
        {
          edges = selection->GetNode(0);
        }

        if(selection->GetNode(1)->GetFieldType() == vtkSelectionNode::VERTEX)
        {
          vertices = selection->GetNode(1);
        }
        else if(selection->GetNode(1)->GetFieldType() == vtkSelectionNode::EDGE)
        {
          edges = selection->GetNode(1);
        }

        vtkIdTypeArray* vertexList = vtkIdTypeArray::SafeDownCast(vertices->GetSelectionList());
        std::cout << "There are " << vertexList->GetNumberOfTuples() << " vertices selected." << std::endl;

        if(vertexList->GetNumberOfTuples() > 0)
        {
          std::cout << "Vertex Ids: ";
        }
        for(vtkIdType i = 0; i < vertexList->GetNumberOfTuples(); i++)
        {
          std::cout << vertexList->GetValue(i) << " ";
        }

        std::cout << std::endl;
        vtkIdTypeArray* edgeList = vtkIdTypeArray::SafeDownCast(edges->GetSelectionList());
        std::cout << "There are " << edgeList->GetNumberOfTuples() << " edges selected." << std::endl;
        if(edgeList->GetNumberOfTuples() > 0)
        {
          std::cout << "Edge Ids: ";
        }

        for(vtkIdType i = 0; i < edgeList->GetNumberOfTuples(); i++)
        {
          std::cout << edgeList->GetValue(i) << " ";
        }
        std::cout << std::endl;
      }

      vtkGraphLayoutView* View;
    };
    vtkStandardNewMacro(RubberBandStyle);

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

      vtkSmartPointer<RubberBandStyle> style =
        vtkSmartPointer<RubberBandStyle>::New();
      style->View = view;
      view->SetInteractorStyle(style);

      view->ResetCamera();
      view->Render();

      view->GetInteractor()->Start();

      return EXIT_SUCCESS;
    }

### CMakeLists.txt

    cmake_minimum_required(VERSION 2.8)

    PROJECT(SelectedVerticesAndEdges)

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

    add_executable(SelectedVerticesAndEdges MACOSX_BUNDLE SelectedVerticesAndEdges.cxx )

    target_link_libraries(SelectedVerticesAndEdges ${VTK_LIBRARIES})

### Download and Build SelectedVerticesAndEdges

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

    cd SelectedVerticesAndEdges/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:

    ./SelectedVerticesAndEdges

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.