AdjacentVertexIterator

#include <vtkMutableUndirectedGraph.h>
#include <vtkSmartPointer.h>
#include <vtkAdjacentVertexIterator.h>
#include <vtkUnsignedCharArray.h>
#include <vtkLookupTable.h>
#include <vtkMutableDirectedGraph.h>
#include <vtkRenderWindow.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkViewTheme.h>
#include <vtkDataSetAttributes.h>
#include <vtkGraphLayoutView.h>

// For compatibility with new VTK generic data arrays
#ifdef vtkGenericDataArray_h
#define InsertNextTupleValue InsertNextTypedTuple
#endif

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

  //create 3 vertices
  vtkIdType v0 = g->AddVertex();
  vtkIdType v1 = g->AddVertex();
  vtkIdType v2 = g->AddVertex();
  vtkIdType v3 = g->AddVertex();

  //add edges
  g->AddEdge(v0, v1);
  g->AddEdge(v0, v2);
  g->AddEdge(v2, v3);

  // Create the color array
  vtkSmartPointer<vtkUnsignedCharArray> vertexColors =
    vtkSmartPointer<vtkUnsignedCharArray>::New();
  vertexColors->SetNumberOfComponents(3);
  vertexColors->SetName("color");

  //setup colors
  unsigned char red[3] = {255, 0, 0};
  unsigned char green[3] = {0, 255, 0};
  unsigned char blue[3] = {0, 0, 255};

  for(unsigned int i = 0; i < 4; i++)
  {
    vertexColors->InsertNextTupleValue(blue);//not connected vertices
  }


  vtkSmartPointer<vtkAdjacentVertexIterator> iterator =
    vtkSmartPointer<vtkAdjacentVertexIterator>::New();
  g->GetAdjacentVertices(0, iterator);

  vertexColors->SetTupleValue(0, red);//origin

  while(iterator->HasNext())
  {
    vtkIdType nextVertex = iterator->Next();
    std::cout << "Next vertex: " << nextVertex << std::endl;
    vertexColors->SetTupleValue(nextVertex, green);//connected vertices
  }

  // Add the color array to the graph
  g->GetVertexData()->AddArray(vertexColors);

  vtkSmartPointer<vtkGraphLayoutView> graphLayoutView =
    vtkSmartPointer<vtkGraphLayoutView>::New();
  graphLayoutView->AddRepresentationFromInput(g);
  graphLayoutView->SetLayoutStrategyToTree();

  graphLayoutView->SetVertexColorArrayName("color");
  graphLayoutView->ColorVerticesOn();

  vtkSmartPointer<vtkViewTheme> theme =
    vtkSmartPointer<vtkViewTheme>::New();
  //theme->SetPointLookupTable(lookupTable);
  theme->ScalePointLookupTableOff();
  graphLayoutView->ApplyViewTheme(theme);


  graphLayoutView->ResetCamera();
  graphLayoutView->GetInteractor()->Initialize();
  graphLayoutView->GetInteractor()->Start();

  return EXIT_SUCCESS;
}

cmake_minimum_required(VERSION 3.3 FATAL_ERROR)

project(AdjacentVertexIterator)

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

cd AdjacentVertexIterator/build 

cmake ..

cmake -DVTK_DIR:PATH=/home/me/vtk_build ..

make

./AdjacentVertexIterator