# NOVCAGraph

VTKExamples/Cxx/Graphs/NOVCAGraph

### Description

- This example shows how to construct a graph to visualize it in ParaView/VisIt using the VTK output file testVertex.vtu.

- Contributed by Sanjaya Gajurel, Case Western Reserve University

### Code

NOVCAGraph.cxx

    #include <vtkVersion.h>
    #include <vtkCellArray.h>
    #include <vtkPoints.h>
    #include <vtkPolyLine.h>
    #include <vtkTriangle.h>
    #include <vtkXMLPolyDataWriter.h>
    #include <vtkPolyData.h>
    #include <vtkUnstructuredGrid.h>
    #include <vtkXMLUnstructuredGridWriter.h>
    #include <vtkSmartPointer.h>

    int main ( int, char *[] )
    {
      // Create 8 Vertices.
      vtkSmartPointer<vtkPoints> points =
        vtkSmartPointer<vtkPoints>::New();

      for ( unsigned int i = 0; i < 2; ++i )
         for ( unsigned int j = 0; j < 4; ++j )
              points->InsertNextPoint( i, j, 0);

       //Create Edges
        vtkSmartPointer<vtkPolyLine> line =
        vtkSmartPointer<vtkPolyLine>::New();
        line->GetPointIds()->SetNumberOfIds(8);
      for ( unsigned int i = 0; i < 8; ++i )
          line->GetPointIds()->SetId(i,i);

       vtkSmartPointer<vtkCellArray> cellArray =
        vtkSmartPointer<vtkCellArray>::New();
       cellArray->InsertNextCell(line);

      // Create a Graph with Vertices and Edges.
      vtkSmartPointer<vtkUnstructuredGrid> grid =
        vtkSmartPointer<vtkUnstructuredGrid>::New();
      grid->SetPoints(points);
      grid->SetCells(VTK_POLY_LINE,cellArray);

      // Write the file
      vtkSmartPointer<vtkXMLUnstructuredGridWriter> writer =
        vtkSmartPointer<vtkXMLUnstructuredGridWriter>::New();
      writer->SetFileName("testVertex.vtu");
    #if VTK_MAJOR_VERSION <= 5
      writer->SetInput(grid);
    #else
      writer->SetInputData(grid);
    #endif

      writer->Write();

      return EXIT_SUCCESS;
    }

### CMakeLists.txt

    cmake_minimum_required(VERSION 2.8)

    PROJECT(NOVCAGraph)

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

    add_executable(NOVCAGraph MACOSX_BUNDLE NOVCAGraph.cxx )

    target_link_libraries(NOVCAGraph ${VTK_LIBRARIES})

### Download and Build NOVCAGraph

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

    cd NOVCAGraph/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:

    ./NOVCAGraph

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.