# CellEdges

VTKExamples/Cxx/Meshes/CellEdges

Other Languages

See (CSharp)

### Code

CellEdges.cxx

    #include <vtkSmartPointer.h>
    #include <vtkTriangle.h>
    #include <vtkCellArray.h>
    #include <vtkPolyData.h>
    #include <vtkIdList.h>

    int main(int, char *[])
    {
      vtkSmartPointer<vtkTriangle> triangle =
        vtkSmartPointer<vtkTriangle>::New();
      triangle->GetPoints()->SetPoint(0, 1.0, 0.0, 0.0);
      triangle->GetPoints()->SetPoint(1, 0.0, 0.0, 0.0);
      triangle->GetPoints()->SetPoint(2, 0.0, 1.0, 0.0);
      triangle->GetPointIds()->SetId ( 0, 0 );
      triangle->GetPointIds()->SetId ( 1, 1 );
      triangle->GetPointIds()->SetId ( 2, 2 );

      std::cout << "The cell has " << triangle->GetNumberOfEdges()
                << " edges." << std::endl;

      for(vtkIdType i = 0; i < triangle->GetNumberOfEdges(); i++)
      {
        vtkCell* edge = triangle->GetEdge(i);

        vtkIdList* pointIdList = edge->GetPointIds();
        std::cout << "Edge " << i << " has " << pointIdList->GetNumberOfIds()
                  << " points."  << std::endl;

        for(vtkIdType p = 0; p < pointIdList->GetNumberOfIds(); p++)
        {
          std::cout << "Edge " << i << " uses point " << pointIdList->GetId(p)
                    << std::endl;
        }

      }

      return EXIT_SUCCESS;
    }

### CMakeLists.txt

    cmake_minimum_required(VERSION 3.3 FATAL_ERROR)

    project(CellEdges)

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

### Download and Build CellEdges

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

    cd CellEdges/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:

    ./CellEdges

WINDOWS USERS

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