ArrangementDcelFace Concept Reference

Definition

A face record in a DCEL data structure. A face represents a region, which may have outer and inner boundaries. A boundary conists of a chain of incident halfedges, referred to as a Connected Component of the Boundary (CCB). A face may be unbounded. Otherwise, it has one or more outer CCBs. A face may also be bounded by inner CCBs, and it may contain isolated vertices in its interior. A planar face may have only one outer CCBs and its inner CCBs are referred to as holes.

See also

ArrangementDcel

ArrangementDcelVertex

ArrangementDcelHalfedge

Types
The non-mutable iterators Outer_ccb_const_iterator, Inner_ccb_const_iterator, Hole_const_iterator, and Isolated_vertex_const_iterator are also defined.
typedef unspecified_type	Vertex
	the corresponding DCEL vertex type.
typedef unspecified_type	Halfedge
	the corresponding DCEL halfedge type.
typedef unspecified_type	Outer_ccb_iterator
	a bidirectional iterator over the outer CCBs of the face.
typedef unspecified_type	Inner_ccb_iterator
	a bidirectional iterator over the inner CCBs of the face.
typedef unspecified_type	Hole_iterator
	a bidirectional iterator over the holes (i.e., inner CCBs) of the face.
typedef unspecified_type	Isolated_vertex_iterator
	a bidirectional iterator over the isolated vertices in inside the face.

Creation
	Arr_dcel_face ()
	default constructor.
void	assign (const Self &other)
	assigns f with the contents of the other face.

Access Functions
All functions below also have const counterparts, returning non-mutable pointers or iterators:
bool	is_unbounded () const
	determines whether the face is unbounded.
Halfedge *	halfedge ()
	obtains an incident halfedge along the outer boundaries of the face.
size_t	number_of_outer_ccbs () const
	obtains the number of outer CCBs of f.
Outer_ccb_iterator	outer_ccbs_begin ()
	obtains a begin iterator for the outer CCBs of f.
Outer_ccb_iterator	outer_ccbs_end ()
	obtains a past-the-end iterator for the outer CCBs of f.
size_t	number_of_inner_ccbs () const
	obtains the number of inner CCBs of f.
Inner_ccb_iterator	inner_ccbs_begin ()
	obtains a begin iterator for the inner CCBs of f.
Inner_ccb_iterator	inner_ccbs_end ()
	obtains a past-the-end iterator for the inner CCBs of f.
size_t	number_of_holes () const
	obtains the number of holes (i.e., inner CCBs) inside f.
Hole_iterator	holes_begin ()
	obtains a begin-iterator for the holes (i.e., inner CCBs) of f.
Hole_iterator	holes_end ()
	obtains a past-the-end iterator for the holes (i.e., inner CCBs) of f.
size_t	number_of_isolated_vertices () const
	obtains the number of isolated vertices inside f.
Isolated_vertex_iterator	isolated_vertices_begin ()
	obtains a begin-iterator for the isolated vertices inside f.
Isolated_vertex_iterator	isolated_vertices_end ()
	obtains a past-the-end iterator for the isolated vertices inside f.

Modifiers
void	set_unbounded (bool flag)
	sets the face as unbounded (if flag is true), or as a bounded face (if it is false).
void	set_halfedge (Halfedge *e)
	sets the incident halfedge.
void	add_outer_ccb (Halfedge *e)
	adds e as an outer CCB of f.
void	erase_outer_ccb (Outer_ccb_iterator it)
	removes the outer CCB that it points to from f.
void	add_inner_ccb (Halfedge *e)
	adds e as an inner CCB of f.
void	erase_inner_ccb (Inner_ccb_iterator it)
	removes the inner CCB that it points to from f.
void	add_hole (Halfedge *e)
	adds e as a hole (i.e., inner CCB) of f.
void	erase_hole (Hole_iterator it)
	removes the hole (i.e., inner CCB) that it points to from f.
void	add_isolated_vertex (Vertex *v)
	adds v as an isolated vertex inside f.
void	erase_isolated_vertex (Isolated_vertex_iterator it)
	removes the isolated vertex that it points to from inside f.

Member Typedef Documentation

Hole_iterator

typedef unspecified_type ArrangementDcelFace::Hole_iterator

a bidirectional iterator over the holes (i.e., inner CCBs) of the face.

Its value-type is Halfedge*.

Inner_ccb_iterator

typedef unspecified_type ArrangementDcelFace::Inner_ccb_iterator

a bidirectional iterator over the inner CCBs of the face.

Its value-type is Halfedge*.

Isolated_vertex_iterator

typedef unspecified_type ArrangementDcelFace::Isolated_vertex_iterator

a bidirectional iterator over the isolated vertices in inside the face.

Its value-type is Vertex*.

Outer_ccb_iterator

typedef unspecified_type ArrangementDcelFace::Outer_ccb_iterator

a bidirectional iterator over the outer CCBs of the face.

Its value-type is Halfedge*.

Member Function Documentation

halfedge()

Halfedge * ArrangementDcelFace::halfedge

(

)

obtains an incident halfedge along the outer boundaries of the face.

If f has no outer boundary, the function returns nullptr.

number_of_outer_ccbs()

size_t ArrangementDcelFace::number_of_outer_ccbs

(

)

const

obtains the number of outer CCBs of f.

In case of planar arrangement this is either 0 or 1.