OutEdgeIterator

VTKEx/Cxx/Graphs/OutEdgeIterator

Question

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Code

OutEdgeIterator.cxx

#include <vtkMutableUndirectedGraph.h>
#include <vtkMutableDirectedGraph.h>
#include <vtkSmartPointer.h>
#include <vtkOutEdgeIterator.h>

static void Undirected();
static void Directed();

int main(int, char *[])
{
  Undirected();
  Directed();

  return EXIT_SUCCESS;
}

void Undirected()
{
  vtkSmartPointer<vtkMutableUndirectedGraph> g =
    vtkSmartPointer<vtkMutableUndirectedGraph>::New();

  // Create a graph
  vtkIdType v0 = g->AddVertex();
  vtkIdType v1 = g->AddVertex();
  vtkIdType v2 = g->AddVertex();

  g->AddEdge(v0, v1);
  g->AddEdge(v1, v2);
  g->AddEdge(v0, v2);

  // Find all outgoing edges connected to a vertex
  vtkSmartPointer<vtkOutEdgeIterator> it =
    vtkSmartPointer<vtkOutEdgeIterator>::New();
  g->GetOutEdges(0, it); // Get the edges connected to vertex 0

  while(it->HasNext())
  {
    vtkOutEdgeType edge = it->Next();
    std::cout << "Edge id: " << edge.Id << " Target: " << edge.Target << std::endl;
  }
}

void Directed()
{
  vtkSmartPointer<vtkMutableDirectedGraph> g =
    vtkSmartPointer<vtkMutableDirectedGraph>::New();

  // Create a graph
  vtkIdType v0 = g->AddVertex();
  vtkIdType v1 = g->AddVertex();
  vtkIdType v2 = g->AddVertex();

  g->AddEdge(v1, v0);
  g->AddEdge(v2, v0);

  {
  std::cout << "Finding edges connected to vertex 0" << std::endl;
  vtkSmartPointer<vtkOutEdgeIterator> it =
    vtkSmartPointer<vtkOutEdgeIterator>::New();
  g->GetOutEdges(0, it);

  while(it->HasNext())
  {
    vtkOutEdgeType edge = it->Next();
    std::cout << "Edge id: " << edge.Id << " Target: " << edge.Target << std::endl;
  }

  std::cout << "Nothing should be output, vertex 0 has no outgoing edges!" << std::endl;
  }

  {
  std::cout << "Finding edges connected to vertex 1" << std::endl;
  vtkSmartPointer<vtkOutEdgeIterator> it =
    vtkSmartPointer<vtkOutEdgeIterator>::New();
  g->GetOutEdges(1, it);

  while(it->HasNext())
  {
    vtkOutEdgeType edge = it->Next();
    std::cout << "Edge id: " << edge.Id << " Target: " << edge.Target << std::endl;
  }
  }

}

CMakeLists.txt

cmake_minimum_required(VERSION 3.3 FATAL_ERROR)

project(OutEdgeIterator)

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

Download and Build OutEdgeIterator

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

cd OutEdgeIterator/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:

./OutEdgeIterator

WINDOWS USERS

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