CGAL 5.1.2 - 2D Arrangements
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#include <CGAL/Arrangement_2.h>
Halfedge.
An object \( e\) of the class Halfedge
represents a halfedge in the arrangement.
A halfedge is directed from its source vertex to its target vertex, and has an incident face lying to its left. Each halfedge has a twin halfedge directed in the opposite direction, where the pair of twin halfedges form together an arrangement edge, that is - a \( 1\)-dimensional cell, associated with planar \( x\)-monotone curve.
Halfedges are stored in doubly-connected lists and form chains. These chains define the inner and outer boundaries of connected components.
Creation | |
Halfedge () | |
default constructor. | |
Access Functions | |
All non-const methods listed below also have | |
bool | is_fictitious () const |
returns whether the halfedge is fictitious (i.e., connects two vertices at infinity and is not associated with a valid curve). | |
Vertex_handle | source () |
returns a handle for the source vertex of e . | |
Vertex_handle | target () |
returns a handle for the target vertex of e . | |
Arr_halfedge_direction | direction () const |
returns the direction of the halfedge: ARR_LEFT_TO_RIGHT if e 's source vertex is lexicographically smaller than it target (so the halfedge is directed from left to right), and ARR_RIGHT_TO_LEFT if it is lexicographically larger than the target (so the halfedge is directed from right to left). | |
Face_handle | face () |
returns the face that e is incident to (The face lies to the left of e ). | |
Halfedge_handle | twin () |
returns the twin halfedge. | |
Halfedge_handle | prev () |
returns e 's predecessor in the connected component it belongs to. | |
Halfedge_handle | next () |
returns e 's successor in the connected component it belongs to. | |
Ccb_halfedge_circulator | ccb () |
returns a circulator that allows traversing the halfedges of the connected component boundary (CCB) that contains e . More... | |
const Traits::X_monotone_curve_2 & | curve () const |
returns the \( x\)-monotone curve associated with e . More... | |
Ccb_halfedge_circulator CGAL::Arrangement_2< Traits, Dcel >::Halfedge::ccb | ( | ) |
returns a circulator that allows traversing the halfedges of the connected component boundary (CCB) that contains e
.
The circulator is initialized to point to e
.
const Traits::X_monotone_curve_2& CGAL::Arrangement_2< Traits, Dcel >::Halfedge::curve | ( | ) | const |
returns the \( x\)-monotone curve associated with e
.
e
is not a fictitious halfedge.