CGAL 5.5.1 - 2D Straight Skeleton and Polygon Offsetting
StraightSkeletonHalfedge_2 Concept Reference

## Definition

Refines:
HalfedgeDSHalfedge

The concept StraightSkeletonHalfedge_2 describes the requirements for the halfedge type of the StraightSkeleton_2 concept. It is a refinement of the HalfedgeDSHalfedge concept.

The StraightSkeletonHalfedge_2 concept requires no geometric embedding at all. The only geometric embedding used by the Straight Skeleton Data Structure are the 2D points in the contour and skeleton vertices. However, for any halfedge, there is a 2D segment implicitly given by its source and target vertices.

Has Models:
CGAL::Straight_skeleton_halfedge_base_2
StraightSkeleton_2
StraightSkeletonHalfedge_2
CGAL::Straight_skeleton_vertex_base_2<Refs,Point,FT>
CGAL::Straight_skeleton_halfedge_base_2<Refs>

## Creation

StraightSkeletonHalfedge_2 ()
Default Constructor.

StraightSkeletonHalfedge_2 (int id)
constructs a halfedge with ID id. More...

## Access Functions

Halfedge_handle defining_contour_edge ()

Halfedge_const_handle defining_contour_edge () const
If this is a bisector halfedge, returns a handle to the inward-facing (non-border) contour halfedge corresponding to the defining contour edge which is to its left; if this is a contour halfedge, returns a handle to itself if is_border() is false, or to its opposite if it is true.

## Queries

bool is_bisector () const
returns true iff this is a bisector (or skeleton) halfedge (i.e. is not a contour halfedge).

bool is_inner_bisector () const
returns true iff this is a bisector and is inner (i.e. is not incident upon a contour vertex).

## ◆ StraightSkeletonHalfedge_2()

 StraightSkeletonHalfedge_2::StraightSkeletonHalfedge_2 ( int id )

constructs a halfedge with ID id.

It is the links to other halfedges that determines if this is a contour edge, a contour-skeleton edge, or an inner-skeleton edge.