SFCGAL: Public C++ API

Classes
struct	SFCGAL::algorithm::NoValidityCheck
	Tag used for variants of algorithm that do not do validity check. More...

class	SFCGAL::Geometry
	OGC/SFA based Geometry abstract class. More...

class	SFCGAL::GeometryCollection
	A GeometryCollection in SFA. More...

class	SFCGAL::LineString
	A LineString in SFA. More...

class	SFCGAL::MultiLineString
	A MultiLineString in SFA. More...

class	SFCGAL::MultiPoint
	A MultiPoint in SFA. More...

class	SFCGAL::MultiPolygon
	A MultiPolygon in SFA. More...

class	SFCGAL::MultiSolid
	A MultiSolid. More...

class	SFCGAL::Point
	A point in SFA. More...

class	SFCGAL::Polygon
	A Polygon in SFA with holes. More...

class	SFCGAL::PolyhedralSurface
	A PolyhedralSurface in SFA modeled as a Polygon soup. More...

class	SFCGAL::Solid
	A Solid modeled with an exteriorShell and interiorShells materialized by PolyhedralSurface. More...

class	SFCGAL::Triangle
	[OGC/SFA]Triangle More...

class	SFCGAL::TriangulatedSurface
	A TriangulatedSurface in SFA modeled as a Triangle soup. More...

Enumerations
enum	SFCGAL::GeometryType { SFCGAL::TYPE_POINT = 1 , SFCGAL::TYPE_LINESTRING = 2 , SFCGAL::TYPE_POLYGON = 3 , SFCGAL::TYPE_MULTIPOINT = 4 , SFCGAL::TYPE_MULTILINESTRING = 5 , SFCGAL::TYPE_MULTIPOLYGON = 6 , SFCGAL::TYPE_GEOMETRYCOLLECTION = 7 , SFCGAL::TYPE_POLYHEDRALSURFACE = 15 , SFCGAL::TYPE_TRIANGULATEDSURFACE = 16 , SFCGAL::TYPE_TRIANGLE = 100 , SFCGAL::TYPE_SOLID = 101 , SFCGAL::TYPE_MULTISOLID = 102 }
	[OGC/SFA]8.2.3 "A common list of codes for geometric types" More...

enum	SFCGAL::CoordinateType { SFCGAL::COORDINATE_XY = 0 , SFCGAL::COORDINATE_XYZ = 1000 , SFCGAL::COORDINATE_XYM = 2000 , SFCGAL::COORDINATE_XYZM = 3000 }
	coordinate types (XY, XYZ, XYM, etc.) More...

Functions
auto	SFCGAL::algorithm::alphaShapes (const Geometry &g, double alpha=1, bool allow_holes=false) -> std::unique_ptr< Geometry >
	Compute the 2D alpha shapes for a geometry https://doc.cgal.org/latest/Alpha_shapes_2/index.html#Chapter_2D_Alpha_Shapes. More...

auto	SFCGAL::algorithm::optimal_alpha_shapes (const Geometry &g, bool allow_holes=false, size_t nb_components=1) -> std::unique_ptr< Geometry >
	Compute the optimal 2D alpha shapes for a geometry https://doc.cgal.org/latest/Alpha_shapes_2/index.html#Chapter_2D_Alpha_Shapes. More...

auto	SFCGAL::algorithm::area (const Geometry &g)
	Compute the 2D area for a Geometry. More...

auto	SFCGAL::algorithm::area3D (const Geometry &g)
	Returns 3D area for a Geometry. More...

auto	SFCGAL::algorithm::convexHull (const Geometry &g)
	Compute the 2D convex hull for a geometry. More...

auto	SFCGAL::algorithm::convexHull3D (const Geometry &g)
	Compute the 3D convex hull for a geometry. More...

auto	SFCGAL::algorithm::difference (const Geometry &ga, const Geometry &gb)
	Difference on 2D geometries. More...

auto	SFCGAL::algorithm::difference3D (const Geometry &ga, const Geometry &gb)
	Difference on 3D geometries. More...

auto	SFCGAL::algorithm::distance (const Geometry &gA, const Geometry &gB)
	Compute the distance between two Geometries. More...

auto	SFCGAL::algorithm::distance3D (const Geometry &gA, const Geometry &gB)
	dispatch distance between two Geometries More...

auto	SFCGAL::algorithm::extrude (const Geometry &g, Kernel::FT dx, Kernel::FT dy, Kernel::FT dz)
	Returns a Geometry equal to the specified Geometry, extruded by the specified displacement. More...

auto	SFCGAL::algorithm::intersection (const Geometry &ga, const Geometry &gb)
	Intersection on 2D geometries. More...

auto	SFCGAL::algorithm::intersection3D (const Geometry &ga, const Geometry &gb)
	Intersection on 3D geometries. More...

auto	SFCGAL::algorithm::intersects (const Geometry &ga, const Geometry &gb)
	Robust intersection test on 2D geometries. More...

auto	SFCGAL::algorithm::intersects3D (const Geometry &ga, const Geometry &gb)
	Robust intersection test on 3D geometries. More...

auto	SFCGAL::algorithm::isValid (const Geometry &g, const double &toleranceAbs=1e-9)
	Check validity of a geometry. More...

void	SFCGAL::algorithm::propagateValidityFlag (Geometry &g, bool valid)
	Sets the geometry flag on a geometry and propagate to every internal geometries. More...

auto	SFCGAL::algorithm::minkowskiSum (const Geometry &gA, const Polygon &gB)
	2D minkowski sum (p+q) More...

auto	SFCGAL::algorithm::offset (const Geometry &g, const double &r)
	[experimental]compute polygon offset More...

template<typename Kernel >
bool	SFCGAL::algorithm::hasPlane3D (const Polygon &polygon, CGAL::Point_3< Kernel > &a, CGAL::Point_3< Kernel > &b, CGAL::Point_3< Kernel > &c)
	Test if a 3D plane can be extracted from a Polygon. More...

auto	SFCGAL::algorithm::approximateMedialAxis (const Geometry &g)
	build an approximate medial axis for a Polygon More...

auto	SFCGAL::algorithm::straightSkeleton (const Geometry &g, bool autoOrientation=true, bool innerOnly=false, bool outputDistanceInM=false, const double &toleranceAbs=1e-8)
	build a 2D straight skeleton for a Polygon More...

auto	SFCGAL::algorithm::straightSkeleton (const Geometry &g, bool autoOrientation, NoValidityCheck, bool innerOnly=false, bool outputDistanceInM=false, const double &toleranceAbs=1e-8)
	build a 2D straight skeleton for a Polygon More...

auto	SFCGAL::algorithm::tesselate (const Geometry &)
	Tesselate a geometry: this will triangulate surfaces (including polyhedral and solid's surfaces) and keep untouched points, lines, etc. More...

auto	SFCGAL::algorithm::union_ (const Geometry &ga, const Geometry &gb)
	Union on 2D geometries. More...

auto	SFCGAL::algorithm::union3D (const Geometry &ga, const Geometry &gb)
	Union on 3D geometries. More...

auto	SFCGAL::algorithm::volume (const Geometry &g)
	Computes the volume of a geometry. More...

Detailed Description

Enumeration Type Documentation

◆ CoordinateType

enum SFCGAL::CoordinateType

coordinate types (XY, XYZ, XYM, etc.)

See also: SFA 2.8.3 LineStringZ = 1003 ( coordinateType + geometryType)

Enumerator
COORDINATE_XY
COORDINATE_XYZ
COORDINATE_XYM
COORDINATE_XYZM

◆ GeometryType

enum SFCGAL::GeometryType

[OGC/SFA]8.2.3 "A common list of codes for geometric types"

Todo:: solid and triangles as non OGC/SFA geometric types?

Warning: codes for abstract classes and unimplemented classes are hidden; code values have are important for WKB

Enumerator
TYPE_POINT
TYPE_LINESTRING
TYPE_POLYGON
TYPE_MULTIPOINT
TYPE_MULTILINESTRING
TYPE_MULTIPOLYGON
TYPE_GEOMETRYCOLLECTION
TYPE_POLYHEDRALSURFACE
TYPE_TRIANGULATEDSURFACE
TYPE_TRIANGLE
TYPE_SOLID
TYPE_MULTISOLID

Function Documentation

◆ alphaShapes()

SFCGAL_API auto SFCGAL::algorithm::alphaShapes	(	const Geometry &	g,
		double	alpha = `1`,
		bool	allow_holes = `false`
	)		-> std::unique_ptr< Geometry >

Compute the 2D alpha shapes for a geometry https://doc.cgal.org/latest/Alpha_shapes_2/index.html#Chapter_2D_Alpha_Shapes.

Since: 1.4.1

◆ approximateMedialAxis()

SFCGAL_API std::unique_ptr< MultiLineString > SFCGAL::algorithm::approximateMedialAxis ( const Geometry & g )

build an approximate medial axis for a Polygon

Parameters

g	input geometry

Precondition: g is a valid geometry

Exceptions

NotImplementedException If g is a Polygon with point touching rings.

◆ area()

SFCGAL_API double SFCGAL::algorithm::area ( const Geometry & g )

Compute the 2D area for a Geometry.

Warning: Z component is ignored, there is no 2D projection for 3D geometries

Precondition: g is a valid geometry

◆ area3D()

SFCGAL_API double SFCGAL::algorithm::area3D ( const Geometry & g )

Returns 3D area for a Geometry.

Warning: Solid area is set to 0 (might be defined as the area of the surface)

Precondition: g is a valid geometry

◆ convexHull()

SFCGAL_API std::unique_ptr< Geometry > SFCGAL::algorithm::convexHull ( const Geometry & g ) -> std::unique_ptr< Geometry >

Compute the 2D convex hull for a geometry.

◆ convexHull3D()

SFCGAL_API std::unique_ptr< Geometry > SFCGAL::algorithm::convexHull3D ( const Geometry & g )

Compute the 3D convex hull for a geometry.

Todo:: improve to handle collinear points and coplanar points

◆ difference()

SFCGAL_API std::unique_ptr< Geometry > SFCGAL::algorithm::difference	(	const Geometry &	ga,
		const Geometry &	gb
	)

Difference on 2D geometries.

Precondition: ga and gb are valid geometries

◆ difference3D()

SFCGAL_API std::unique_ptr< Geometry > SFCGAL::algorithm::difference3D	(	const Geometry &	ga,
		const Geometry &	gb
	)

Difference on 3D geometries.

Assume z = 0 if needed

Precondition: ga and gb are valid geometries

◆ distance()

SFCGAL_API double SFCGAL::algorithm::distance	(	const Geometry &	gA,
		const Geometry &	gB
	)

Compute the distance between two Geometries.

Precondition: gA is a valid geometry; gB is a valid geometry

◆ distance3D()

SFCGAL_API double SFCGAL::algorithm::distance3D	(	const Geometry &	gA,
		const Geometry &	gB
	)

dispatch distance between two Geometries

Todo:: complete with solid Compute distance between two 3D Geometries

Precondition: gA is a valid geometry; gB is a valid geometry

◆ extrude()

SFCGAL_API std::unique_ptr< Geometry > SFCGAL::algorithm::extrude	(	const Geometry &	g,
		Kernel::FT	dx,
		Kernel::FT	dy,
		Kernel::FT	dz
	)

Returns a Geometry equal to the specified Geometry, extruded by the specified displacement.

Parameters

g	The specified Geometry.
dx	The component of the specified displacement in the x-direction.
dy	The component of the specified displacement in the y-direction.
dz	The component of the specified displacement in the z-direction.

Returns: A Geometry equal to g extruded by the displacement vector {dx, dy, dz}.

Precondition: g must be a valid geometry.; dx, dy and dz must all be finite.

Note: If g is such that g.isMeasured() is true, then, since there is no common expectation of the values of the measures on the returned Geometry, all measures from the result are removed.

◆ hasPlane3D()

template<typename Kernel >

bool SFCGAL::algorithm::hasPlane3D	(	const Polygon &	polygon,
		CGAL::Point_3< Kernel > &	a,
		CGAL::Point_3< Kernel > &	b,
		CGAL::Point_3< Kernel > &	c
	)

Test if a 3D plane can be extracted from a Polygon.

◆ intersection()

SFCGAL_API std::unique_ptr< Geometry > SFCGAL::algorithm::intersection	(	const Geometry &	ga,
		const Geometry &	gb
	)

Intersection on 2D geometries.

Precondition: ga and gb are valid geometries

◆ intersection3D()

SFCGAL_API std::unique_ptr< Geometry > SFCGAL::algorithm::intersection3D	(	const Geometry &	ga,
		const Geometry &	gb
	)

Intersection on 3D geometries.

Assume z = 0 if needed

Precondition: ga and gb are valid geometries

◆ intersects()

SFCGAL_API bool SFCGAL::algorithm::intersects	(	const Geometry &	ga,
		const Geometry &	gb
	)

Robust intersection test on 2D geometries.

Force projection to z=0 if needed

Precondition: ga and gb are valid geometries

◆ intersects3D()

SFCGAL_API bool SFCGAL::algorithm::intersects3D	(	const Geometry &	ga,
		const Geometry &	gb
	)

Robust intersection test on 3D geometries.

Assume z = 0 if needed

Precondition: ga and gb are valid geometries

◆ isValid()

SFCGAL_API const Validity SFCGAL::algorithm::isValid	(	const Geometry &	g,
		const double &	toleranceAbs
	)		-> const Validity

Check validity of a geometry.

◆ minkowskiSum()

SFCGAL_API std::unique_ptr< Geometry > SFCGAL::algorithm::minkowskiSum	(	const Geometry &	gA,
		const Polygon &	gB
	)

2D minkowski sum (p+q)

Warning: If gA is a polygon, its orientation is taken into account. A "reversed" polygon (with a clockwise-oriented exterior ring) will involve a minkowski difference rather than a sum.

Todo:: missing cases (union)

Precondition: gA and gB are valid geometries

◆ offset()

SFCGAL_API std::unique_ptr< MultiPolygon > SFCGAL::algorithm::offset	(	const Geometry &	g,
		const double &	r
	)

[experimental]compute polygon offset

Warning: test in order to compare with minkowski sum

Precondition: g is a valid Geometry

◆ optimal_alpha_shapes()

SFCGAL_API auto SFCGAL::algorithm::optimal_alpha_shapes	(	const Geometry &	g,
		bool	allow_holes = `false`,
		size_t	nb_components = `1`
	)		-> std::unique_ptr< Geometry >

Compute the optimal 2D alpha shapes for a geometry https://doc.cgal.org/latest/Alpha_shapes_2/index.html#Chapter_2D_Alpha_Shapes.

Since: 1.4.1

◆ propagateValidityFlag()

SFCGAL_API void SFCGAL::algorithm::propagateValidityFlag	(	Geometry &	g,
		bool	valid
	)

Sets the geometry flag on a geometry and propagate to every internal geometries.

◆ straightSkeleton() [1/2]

SFCGAL_API std::unique_ptr< MultiLineString > SFCGAL::algorithm::straightSkeleton	(	const Geometry &	g,
		bool	autoOrientation,
		NoValidityCheck	,
		bool	innerOnly = `false`,
		bool	outputDistanceInM = `false`,
		const double &	toleranceAbs = `1e-8`
	)

build a 2D straight skeleton for a Polygon

Parameters

g	input geometry
autoOrientation	check and fix polygon orientation
outputM	whether to output the distance to border as M
toleranceAbs	Distance tolerance between returned points. A line must have a maximum distance of toleranceAbs.

Precondition: g is a valid geometry

Warning: No actual validity check is done

Exceptions

NotImplementedException If g is a Polygon with point touching rings.

◆ straightSkeleton() [2/2]

SFCGAL_API std::unique_ptr< MultiLineString > SFCGAL::algorithm::straightSkeleton	(	const Geometry &	g,
		bool	autoOrientation = `true`,
		bool	innerOnly = `false`,
		bool	outputDistanceInM = `false`,
		const double &	toleranceAbs = `1e-8`
	)

build a 2D straight skeleton for a Polygon

Todo:: add supports for TriangulatedSurface and PolyhedralSurface

Parameters

g	input geometry
autoOrientation	check and fix polygon orientation
outputM	whether to output the distance to border as M
toleranceAbs	Distance tolerance between returned points. A line must have a maximum distance of toleranceAbs.

Precondition: g is a valid geometry

Exceptions

NotImplementedException If g is a Polygon with point touching rings.

◆ tesselate()

SFCGAL_API std::unique_ptr< SFCGAL::Geometry > SFCGAL::algorithm::tesselate ( const Geometry & )

Tesselate a geometry: this will triangulate surfaces (including polyhedral and solid's surfaces) and keep untouched points, lines, etc.

Precondition: g is a valid geometry

◆ union3D()

SFCGAL_API std::unique_ptr< Geometry > SFCGAL::algorithm::union3D	(	const Geometry &	ga,
		const Geometry &	gb
	)

Union on 3D geometries.

Assume z = 0 if needed

Precondition: ga and gb are valid geometries

◆ union_()

SFCGAL_API std::unique_ptr< Geometry > SFCGAL::algorithm::union_	(	const Geometry &	ga,
		const Geometry &	gb
	)

Union on 2D geometries.

Precondition: ga and gb are valid geometries

◆ volume()

SFCGAL_API const Kernel::FT SFCGAL::algorithm::volume ( const Geometry & g )

Computes the volume of a geometry.

Precondition: g is a valid Geometry

Classes

Enumerations

Functions

Detailed Description

Enumeration Type Documentation

◆ CoordinateType

◆ GeometryType

Function Documentation

◆ alphaShapes()

◆ approximateMedialAxis()

◆ area()

◆ area3D()

◆ convexHull()

◆ convexHull3D()

◆ difference()

◆ difference3D()

◆ distance()

◆ distance3D()

◆ extrude()

◆ hasPlane3D()

◆ intersection()

◆ intersection3D()

◆ intersects()

◆ intersects3D()

◆ isValid()

◆ minkowskiSum()

◆ offset()

◆ optimal_alpha_shapes()

◆ propagateValidityFlag()

◆ straightSkeleton() [1/2]

◆ straightSkeleton() [2/2]

◆ tesselate()

◆ union3D()

◆ union_()

◆ volume()