AdjacentVertexIterator

#include <vtkAdjacentVertexIterator.h>
#include <vtkDataSetAttributes.h>
#include <vtkGraphLayoutView.h>
#include <vtkLookupTable.h>
#include <vtkMutableDirectedGraph.h>
#include <vtkNamedColors.h>
#include <vtkNew.h>
#include <vtkRenderWindow.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkTree.h>
#include <vtkUnsignedCharArray.h>
#include <vtkViewTheme.h>

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

int main(int, char*[])
{
  vtkNew<vtkNamedColors> colors;

  vtkNew<vtkMutableDirectedGraph> g;

  // Create 4 vertices.
  vtkIdType v0 = g->AddVertex();
  vtkIdType v1 = g->AddVertex();
  vtkIdType v2 = g->AddVertex();
  vtkIdType v3 = g->AddVertex();

  // Add the edges.
  g->AddEdge(v0, v1);
  g->AddEdge(v0, v2);
  g->AddEdge(v2, v3);

  vtkNew<vtkTree> tree;
  bool success = tree->CheckedShallowCopy(g);
  std::cout << "Is it a tree? " << std::boolalpha << success << std::endl;

  // Create the color array.
  vtkNew<vtkUnsignedCharArray> vertexColors;
  vertexColors->SetNumberOfComponents(1);
  vertexColors->SetName("Color");

  vtkNew<vtkLookupTable> lookupTable;
  lookupTable->SetNumberOfTableValues(3);
  // Origin
  lookupTable->SetTableValue(0, colors->GetColor4d("Red").GetData());
  // Unconnected vertices
  lookupTable->SetTableValue(1, colors->GetColor4d("Blue").GetData());
  // Connected vertices
  lookupTable->SetTableValue(2, colors->GetColor4d("Green").GetData());
  lookupTable->Build();

  // Setup the colors.
  vertexColors->InsertNextValue(0);
  vertexColors->InsertNextValue(1);
  // vertexColors->InsertNextValue(2);
  // vertexColors->InsertNextValue(3);

  vtkNew<vtkAdjacentVertexIterator> iterator;
  tree->GetAdjacentVertices(0, iterator);

  auto i = 2;
  while (iterator->HasNext())
  {
    vtkIdType nextVertex = iterator->Next();
    std::cout << "Next adjacent vertex: " << nextVertex << std::endl;
    vertexColors->InsertNextValue(i);
    ++i;
  }

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

  vtkNew<vtkGraphLayoutView> graphLayoutView;
  graphLayoutView->AddRepresentationFromInput(tree);
  graphLayoutView->SetLayoutStrategyToTree();
  graphLayoutView->SetVertexColorArrayName("Color");
  graphLayoutView->ColorVerticesOn();

  vtkNew<vtkViewTheme> theme;
  theme->SetPointLookupTable(lookupTable);
  theme->ScalePointLookupTableOff();
  graphLayoutView->ApplyViewTheme(theme);

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

  return EXIT_SUCCESS;
}

cmake_minimum_required(VERSION 3.12 FATAL_ERROR)

project(AdjacentVertexIterator)

find_package(VTK COMPONENTS 
  CommonColor
  CommonCore
  CommonDataModel
  InteractionStyle
  RenderingContextOpenGL2
  RenderingCore
  RenderingFreeType
  RenderingGL2PSOpenGL2
  RenderingOpenGL2
  ViewsCore
  ViewsInfovis
)

if (NOT VTK_FOUND)
  message(FATAL_ERROR "AdjacentVertexIterator: Unable to find the VTK build folder.")
endif()

# Prevent a "command line is too long" failure in Windows.
set(CMAKE_NINJA_FORCE_RESPONSE_FILE "ON" CACHE BOOL "Force Ninja to use response files.")
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}
)

cd AdjacentVertexIterator/build

cmake ..

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

make

./AdjacentVertexIterator