Straight Skeleton Construction Functions

The following functions are used to construct the inward or outward straight skeleton of a polygon.

Functions
template<typename PointIterator, typename HoleIterator, typename SsK = CGAL::Exact_predicates_inexact_constructions_kernel>
std::shared_ptr< Straight_skeleton_2< SsK > >	CGAL::create_interior_straight_skeleton_2 (PointIterator outer_contour_vertices_begin, PointIterator outer_contour_vertices_end, HoleIterator holes_begin, HoleIterator holes_end, const SsK &k=SsK())
	creates a straight skeleton in the interior of the 2D polygon with holes.
template<typename PointIterator, typename SsK = CGAL::Exact_predicates_inexact_constructions_kernel>
std::shared_ptr< Straight_skeleton_2< SsK > >	CGAL::create_interior_straight_skeleton_2 (PointIterator outer_contour_vertices_begin, PointIterator outer_contour_vertices_end, const SsK &k=SsK())
	creates a straight skeleton in the interior of the 2D polygon.
template<typename Polygon, typename SsK = CGAL::Exact_predicates_inexact_constructions_kernel>
std::shared_ptr< Straight_skeleton_2< SsK > >	CGAL::create_interior_straight_skeleton_2 (const Polygon &polygon, const SsK &k=SsK())
	creates a straight skeleton in the interior of the 2D polygon polygon.
template<typename FT, typename PointIterator, typename SsK = CGAL::Exact_predicates_inexact_constructions_kernel>
std::shared_ptr< Straight_skeleton_2< SsK > >	CGAL::create_exterior_straight_skeleton_2 (const FT &max_offset, PointIterator vertices_begin, PointIterator vertices_end, const SsK &k=SsK())
	creates a straight skeleton in the exterior of a 2D polygon with holes.
template<typename FT, typename Polygon, typename SsK = CGAL::Exact_predicates_inexact_constructions_kernel>
std::shared_ptr< Straight_skeleton_2< SsK > >	CGAL::create_exterior_straight_skeleton_2 (const FT &max_offset, const Polygon &P, const SsK &k=SsK())
	creates a straight skeleton in the exterior of a 2D polygon with holes.

Function Documentation

create_exterior_straight_skeleton_2() [1/2]

template<typename FT, typename Polygon, typename SsK = CGAL::Exact_predicates_inexact_constructions_kernel>

std::shared_ptr< Straight_skeleton_2< SsK > > CGAL::create_exterior_straight_skeleton_2	(	const FT &	max_offset,
		const Polygon &	P,
		const SsK &	k = SsK() )

#include <CGAL/create_straight_skeleton_2.h>

creates a straight skeleton in the exterior of a 2D polygon with holes.

The function returns a straight skeleton in the limited exterior of the 2D polygon P. The skeleton in the limited exterior of P is the skeleton in the interior of a polygon Q with P as its hole and a rectangular frame F as outer boundary. The outer boundary F is constructed by enlarging the bounding box of P a distance d. d is a margin sufficiently large to allow an outer offset at distance max_offset to be obtained from this exterior skeleton, as computed by the function compute_outer_frame_margin().

Template Parameters

SsK	must be a model of Kernel.
FT	must be a model of FieldNumberType convertible to SsK::FT.
Polygon	must be a model of SequenceContainer with value type InK::Point_2 (e.g. Polygon_2<InK>) or a model of GeneralPolygonWithHoles_2 (e.g. Polygon_with_holes_2<InK>).

Note

Cartesian_converter is used to convert from InK::Point_2 to SsK::Point_2, if they differ.

Precondition

P is a weakly simple, counterclockwise polygon with clockwise oriented holes.

Holes neither intersect each other nor the outer boundary.

All the weights must be (strictly) positive.

max_offset is positive.

See also

CGAL::create_interior_straight_skeleton_2()

CGAL::Straight_skeleton_builder_2

create_exterior_straight_skeleton_2() [2/2]

template<typename FT, typename PointIterator, typename SsK = CGAL::Exact_predicates_inexact_constructions_kernel>

std::shared_ptr< Straight_skeleton_2< SsK > > CGAL::create_exterior_straight_skeleton_2	(	const FT &	max_offset,
		PointIterator	vertices_begin,
		PointIterator	vertices_end,
		const SsK &	k = SsK() )

#include <CGAL/create_straight_skeleton_2.h>

creates a straight skeleton in the exterior of a 2D polygon with holes.

The function returns a straight skeleton in the limited exterior of the 2D polygon P given by the point sequence [vertices_begin,vertices_end). The skeleton in the limited exterior of P is the skeleton in the interior of a polygon Q with P as its hole and a rectangular frame F as outer boundary. The outer boundary F is constructed by enlarging the bounding box of P a distance d. d is a margin sufficiently large to allow an outer offset at distance max_offset to be obtained from this exterior skeleton, as computed by the function compute_outer_frame_margin().

Template Parameters

SsK	must be a model of Kernel.
FT	must be a model of FieldNumberType convertible to SsK::FT.
PointIterator	must be a model of InputIterator with value type InK::Point_2.

Note

Cartesian_converter is used to convert from InK::Point_2 to SsK::Point_2, if they differ.

Precondition

vertices_begin and vertices_end describe a weakly simple polygon that is oriented counterclockwise.

See also

CGAL::create_interior_straight_skeleton_2()

CGAL::Straight_skeleton_builder_2

Examples

Straight_skeleton_2/create_straight_skeleton_2.cpp.

create_interior_straight_skeleton_2() [1/3]

template<typename Polygon, typename SsK = CGAL::Exact_predicates_inexact_constructions_kernel>

std::shared_ptr< Straight_skeleton_2< SsK > > CGAL::create_interior_straight_skeleton_2	(	const Polygon &	polygon,
		const SsK &	k = SsK() )

#include <CGAL/create_straight_skeleton_2.h>

creates a straight skeleton in the interior of the 2D polygon polygon.

Warning

Holes of the polygon are ignored. If you also need the exterior skeleton for the holes, you should call CGAL::create_interior_straight_skeleton_2() for each hole.

Template Parameters

Polygon	must be a model of SequenceContainer with value type InK::Point_2 (e.g. Polygon_2<InK>) or a model of GeneralPolygonWithHoles_2 (e.g. Polygon_with_holes_2<InK>).
SsK	must be a model of Kernel.

Note

Cartesian_converter is used to convert from InK::Point_2 to SsK::Point_2, if they differ.

Precondition

polygon is a weakly simple, counterclockwise polygon with clockwise oriented holes.

Holes neither intersect each other nor the outer boundary.

See also

CGAL::create_exterior_straight_skeleton_2()

CGAL::Straight_skeleton_builder_2

create_interior_straight_skeleton_2() [2/3]

template<typename PointIterator, typename SsK = CGAL::Exact_predicates_inexact_constructions_kernel>

std::shared_ptr< Straight_skeleton_2< SsK > > CGAL::create_interior_straight_skeleton_2	(	PointIterator	outer_contour_vertices_begin,
		PointIterator	outer_contour_vertices_end,
		const SsK &	k = SsK() )

#include <CGAL/create_straight_skeleton_2.h>

creates a straight skeleton in the interior of the 2D polygon.

The outer boundary of the polygon is given by the point sequence [outer_contour_vertices_begin,outer_contour_vertices_end).

Template Parameters

PointIterator	must be a model of InputIterator with value type InK::Point_2.
SsK	must be a model of Kernel.

Note

Cartesian_converter is used to convert from InK::Point_2 to SsK::Point_2, if they differ.

Precondition

the range [outer_contour_vertices_begin, outer_contour_vertices_end) describes a weakly simple polygon that is oriented counterclockwise.

See also

CGAL::create_exterior_straight_skeleton_2()

CGAL::Straight_skeleton_builder_2

create_interior_straight_skeleton_2() [3/3]

template<typename PointIterator, typename HoleIterator, typename SsK = CGAL::Exact_predicates_inexact_constructions_kernel>

std::shared_ptr< Straight_skeleton_2< SsK > > CGAL::create_interior_straight_skeleton_2	(	PointIterator	outer_contour_vertices_begin,
		PointIterator	outer_contour_vertices_end,
		HoleIterator	holes_begin,
		HoleIterator	holes_end,
		const SsK &	k = SsK() )

#include <CGAL/create_straight_skeleton_2.h>

creates a straight skeleton in the interior of the 2D polygon with holes.

The outer boundary of the polygon is given by the point sequence [outer_contour_vertices_begin,outer_contour_vertices_end) and its holes given by [holes_begin, holes_end).

Template Parameters

PointIterator	must be a model of InputIterator with value type InK::Point_2.
HoleIterator	must be a model of InputIterator with value_type a model of SequenceContainer with value type InK::Point_2.
SsK	must be a model of Kernel.

Note

Cartesian_converter is used to convert from InK::Point_2 to SsK::Point_2, if they differ.

Precondition

the range [outer_contour_vertices_begin, outer_contour_vertices_end) describes a weakly simple polygon that is oriented counterclockwise. \pre the range [holes_begin, holes_end) describes a sequence of weakly simple polygons that are oriented clockwise.

Holes neither intersect each other nor the outer boundary.

See also

CGAL::create_exterior_straight_skeleton_2()

CGAL::Straight_skeleton_builder_2

Examples

Straight_skeleton_2/create_offset_polygons_2.cpp, Straight_skeleton_2/create_straight_skeleton_2.cpp, Straight_skeleton_2/create_straight_skeleton_from_polygon_with_holes_2.cpp, and Straight_skeleton_2/show_straight_skeleton.cpp.