CGAL 5.2 - CGAL and the Boost Graph Library
CGAL and the Boost Graph Library Reference

Andreas Fabri, Fernando Cacciola, Philipp Moeller, and Ron Wein
This package provides a framework for interfacing CGAL data structures with the algorithms of the Boost Graph Library, or BGL for short. It allows to run graph algorithms directly on CGAL data structures which are model of the BGL graph concepts, for example the shortest path algorithm on a Delaunay triangulation in order to compute the Euclidean minimum spanning tree. Furthermore, it introduces several new graph concepts describing halfedge data structures.
Introduced in: CGAL 3.3
BibTeX: cgal:cfw-cbgl-20b
License: LGPL

Classified Reference Pages



CGAL Classes Adapted for the Graph API

A number of CGAL structures have been adapted as graphs for the Bgl. All adapted types are listed here. The pages document which concepts they model, the properties they support, and any possible caveats that a user might encounter.

Helper Classes

Helper Functions



Euler Operations


Conversion Functions

Graph Adaptors

Partitioning Methods

I/O Functions


 Specializations of boost::graph_traits
 The Bgl defines the class template boost::graph_traits as a uniform interface to the properties and types of graph types.
 Named Parameters
 The algorithms of the Boost Graph Library (Bgl) often have many parameters with default values that are appropriate for most cases.
 We extend the Boost Graph Library (Bgl for short) with a set of new concepts.
 The property tags model of the boost concept PropertyTag.
 Dynamic Properties
 The dynamic property tags enable to associate information to simplices of a FaceGraph on the fly.
 External Indices
 A number of BGL and CGAL algorithms require the graph to have (initialized) integer-like indices for its vertices, edges, or faces.
 Helper Functions
 Generic convenience functions for testing if an edge is a border edge, if a mesh is triangular, for conversion between models of different FaceGraph concepts, etc.
 Iterators and Circulators
 Several iterators and circulators are provided that enable, for example, to iterate through the halfedges incident to a given face or vertex.
 Selection Functions
 Several functions to enlarge or reduce a k-ring selection of vertices, edges, or faces.
 Graph Adaptors
 Graph adaptors are classes that build an interface over an existing graph to provide new functionalities.
 Euler Operations
 We call high level operations that maintain the validity of a halfedge graph Euler Operations.
 Partitioning Operations
 Methods to split a mesh into subdomains, using the library METIS or a graphcut implementation.
 I/O Functions
 Methods to read and write graphs.


file  partition.h
 Convenience header file including the headers for all the partitioning-related free functions of this package.
file  graph_traits_inheritance_macros.h
 Convenience header file defining the necessary specializations and overloads to make a class, inheriting from a model of a face graph concept, a model of that face graph concept itself.


template<typename Graph , typename Visitor , typename IsTerminal >
void CGAL::split_graph_into_polylines (const Graph &graph, Visitor &polyline_visitor, IsTerminal is_terminal)
 splits into polylines the graph g at vertices of degree greater than 2 and at vertices for which is_terminal(v,graph)==true. More...

Function Documentation

◆ split_graph_into_polylines()

template<typename Graph , typename Visitor , typename IsTerminal >
void CGAL::split_graph_into_polylines ( const Graph &  graph,
Visitor &  polyline_visitor,
IsTerminal  is_terminal 

#include <CGAL/boost/graph/split_graph_into_polylines.h>

splits into polylines the graph g at vertices of degree greater than 2 and at vertices for which is_terminal(v,graph)==true.

The polylines are reported using a visitor.

Template Parameters
Grapha model of the boost concepts VertexListGraph and EdgeListGraph.
Visitora class that provides:
  • void start_new_polyline() called when starting the description of a polyline.
  • void add_node(typename boost::graph_traits<Graph>::vertex_descriptor v) called for each vertex v of the polyline currently described. If the polyline is closed this function will be called twice for the first vertex of the cycle picked (once after calling start_new_polyline() and once before the call to end_polyline().
  • void end_polyline() called when the description of a polyline is finished.
IsTerminalA functor providing bool operator()(boost::graph_traits<Graph>::vertex_descriptor v, const Graph& g) const returning true if the vertex v of degree 2 is a polyline endpoint and false otherwise.

An overload without is_terminal is provided if no vertices but those of degree different from 2 are polyline endpoints.