HalfedgeGraph Concept Reference

Definition

The concept HalfedgeGraph is a refinement of the BGL concept IncidenceGraph and adds the notion of a halfedge: Each edge is associated with two opposite halfedges with source and target vertices swapped. Furthermore, halfedges have a successor and predecessor, and form cycles we call faces. However, this concept does not introduce a face type. A HalfedgeGraph is undirected and does not allow parallel edges.

Using the composition of the successor and opposite functions results in another cycle, namely the cycle of halfedges which are incident to the same vertex. We refer to Iterators and Circulators for a description of iterators and circulators for these halfedge cycles.

A partial specialization must be provided for CGAL::graph_has_property for each internal property map available.

Associated Types

boost::graph_traits<HalfedgeGraph>::vertex_descriptor	A vertex descriptor corresponds to a unique vertex in an abstract graph instance. A vertex descriptor must be DefaultConstructible, Assignable, EqualityComparable, and Hashable.
boost::graph_traits<HalfedgeGraph>::halfedge_descriptor	A halfedge descriptor corresponds to a unique halfedge in an abstract graph instance. A halfedge descriptor must be DefaultConstructible, Assignable, EqualityComparable, and Hashable.
boost::graph_traits<HalfedgeGraph>::edge_descriptor	An edge descriptor corresponds to a unique edge in an abstract graph instance. An edge descriptor must be DefaultConstructible, Assignable, EqualityComparable, and Hashable.

Refines

IncidenceGraph

PropertyGraph

A model of HalfedgeGraph must have the interior property vertex_point attached to its vertices.

Has models

See Boost Graph Traits Specializations

See also

Graph Concepts

Examples

BGL_polyhedron_3/normals.cpp.

Related Functions
(Note that these are not member functions.)
template<typename HalfedgeGraph >
boost::graph_traits< HalfedgeGraph >::edge_descriptor	edge (boost::graph_traits< HalfedgeGraph >::halfedge_descriptor h, const HalfedgeGraph &g)
	returns the edge corresponding to halfedges h and opposite(h,g), with the following invariant halfedge(edge(h,g),g)==h.
template<typename HalfedgeGraph >
boost::graph_traits< HalfedgeGraph >::halfedge_descriptor	halfedge (boost::graph_traits< HalfedgeGraph >::edge_descriptor f, const HalfedgeGraph &g)
	returns one of the halfedges corresponding to e.
template<typename HalfedgeGraph >
boost::graph_traits< HalfedgeGraph >::halfedge_descriptor	halfedge (boost::graph_traits< HalfedgeGraph >::vertex_descriptor v, const HalfedgeGraph &g)
	returns a halfedge with target v.
template<typename HalfedgeGraph >
std::pair< boost::graph_traits< HalfedgeGraph >::halfedge_descriptor, bool >	halfedge (boost::graph_traits< HalfedgeGraph >::vertex_descriptor u, boost::graph_traits< HalfedgeGraph >::vertex_descriptor v, const HalfedgeGraph &g)
	returns the halfedge with source u and target v.
template<typename HalfedgeGraph >
boost::graph_traits< HalfedgeGraph >::halfedge_descriptor	opposite (boost::graph_traits< HalfedgeGraph >::halfedge_descriptor h, const HalfedgeGraph &g)
	returns the halfedge with source and target swapped.
template<typename HalfedgeGraph >
boost::graph_traits< HalfedgeGraph >::vertex_descriptor	source (boost::graph_traits< HalfedgeGraph >::halfedge_descriptor h, const HalfedgeGraph &g)
	returns the source vertex of h.
template<typename HalfedgeGraph >
boost::graph_traits< HalfedgeGraph >::vertex_descriptor	target (boost::graph_traits< HalfedgeGraph >::halfedge_descriptor h, const HalfedgeGraph &g)
	returns the target vertex of h.
template<typename HalfedgeGraph >
boost::graph_traits< HalfedgeGraph >::halfedge_descriptor	next (boost::graph_traits< HalfedgeGraph >::halfedge_descriptor h, const HalfedgeGraph &g)
	returns the next halfedge around its face.
template<typename HalfedgeGraph >
boost::graph_traits< HalfedgeGraph >::halfedge_descriptor	prev (boost::graph_traits< HalfedgeGraph >::halfedge_descriptor h, const HalfedgeGraph &g)
	returns the previous halfedge around its face.

Friends And Related Function Documentation

halfedge()

template<typename HalfedgeGraph >

std::pair< boost::graph_traits< HalfedgeGraph >::halfedge_descriptor, bool > halfedge ( boost::graph_traits< HalfedgeGraph >::vertex_descriptor  u, boost::graph_traits< HalfedgeGraph >::vertex_descriptor  v, const HalfedgeGraph &  g  )

related

returns the halfedge with source u and target v.

The Boolean is true, iff this halfedge exists.