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TreeBFSIterator

vtk-examples/Cxx/Graphs/TreeBFSIterator

Question

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Code

TreeBFSIterator.cxx

#include <vtkMutableDirectedGraph.h>
#include <vtkNew.h>
#include <vtkTree.h>
#include <vtkTreeBFSIterator.h>

int main(int argc, char* argv[])
{
  // create a tree
  vtkNew<vtkMutableDirectedGraph> g;

  vtkIdType v1 = g->AddVertex();
  vtkIdType v2 = g->AddVertex();
  vtkIdType v3 = g->AddVertex();

  g->AddEdge(v1, v2);
  g->AddEdge(v1, v3);

  vtkNew<vtkTree> tree;
  tree->CheckedShallowCopy(g);

  // setup the iterator
  vtkIdType root = 0;

  vtkNew<vtkTreeBFSIterator> bfsIterator;
  bfsIterator->SetStartVertex(root);
  bfsIterator->SetTree(tree);

  // traverse the tree in a breadth first fashion
  while (bfsIterator->HasNext())
  {
    vtkIdType nextVertex = bfsIterator->Next();
    std::cout << "Next vertex: " << nextVertex << std::endl;
  }

  return EXIT_SUCCESS;
}

CMakeLists.txt

cmake_minimum_required(VERSION 3.12 FATAL_ERROR)

project(TreeBFSIterator)

find_package(VTK COMPONENTS 
  CommonCore
  CommonDataModel
  QUIET
)

if (NOT VTK_FOUND)
  message(FATAL_ERROR "TreeBFSIterator: 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(TreeBFSIterator MACOSX_BUNDLE TreeBFSIterator.cxx )
  target_link_libraries(TreeBFSIterator PRIVATE ${VTK_LIBRARIES}
)
# vtk_module_autoinit is needed
vtk_module_autoinit(
  TARGETS TreeBFSIterator
  MODULES ${VTK_LIBRARIES}
)

Download and Build TreeBFSIterator

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

cd TreeBFSIterator/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:

./TreeBFSIterator

WINDOWS USERS

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