VTK/Examples/Cxx/Graphs/OutEdgeIterator

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;
    }
  }
  
}

Please try the new VTKExamples website.

CMakeLists.txt

cmake_minimum_required(VERSION 2.8)

PROJECT(OutEdgeIterator)

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

add_executable(OutEdgeIterator MACOSX_BUNDLE OutEdgeIterator.cxx)

if(VTK_LIBRARIES)
  target_link_libraries(OutEdgeIterator ${VTK_LIBRARIES})
else()
  target_link_libraries(OutEdgeIterator vtkHybrid vtkWidgets)
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 PLEASE NOTE: Be sure to add the VTK bin directory to your path. This will resolve the VTK dll's at run time.