CGAL::Ray_2< Kernel > Class Template Reference

#include <CGAL/Ray_2.h>

Definition

template<typename Kernel>
class CGAL::Ray_2< Kernel >

An object r of the data type Ray_2 is a directed straight ray in the two-dimensional Euclidean plane \( \E^2\).

It starts in a point called the source of r and goes to infinity.

Is model of

Kernel::Ray_2

Creation
	Ray_2 (const Point_2< Kernel > &p, const Point_2< Kernel > &q)
	introduces a ray r with source p and passing through point q.
	Ray_2 (const Point_2< Kernel > &p, const Direction_2< Kernel > &d)
	introduces a ray r starting at source p with direction d.
	Ray_2 (const Point_2< Kernel > &p, const Vector_2< Kernel > &v)
	introduces a ray r starting at source p with the direction of v.
	Ray_2 (const Point_2< Kernel > &p, const Line_2< Kernel > &l)
	introduces a ray r starting at source p with the same direction as l.

Operations
bool	operator== (const Ray_2< Kernel > &h) const
	Test for equality: two rays are equal, iff they have the same source and the same direction.
bool	operator!= (const Ray_2< Kernel > &h) const
	Test for inequality.
Point_2< Kernel >	source () const
	returns the source of r.
Point_2< Kernel >	point (const Kernel::FT i) const
	returns a point on r.
Direction_2< Kernel >	direction () const
	returns the direction of r.
Vector_2< Kernel >	to_vector () const
	returns a vector giving the direction of r.
Line_2< Kernel >	supporting_line () const
	returns the line supporting r which has the same direction.
Ray_2< Kernel >	opposite () const
	returns the ray with the same source and the opposite direction.

Predicates
bool	is_degenerate () const
	ray r is degenerate, if the source and the second defining point fall together (that is if the direction is degenerate).
bool	is_horizontal () const
bool	is_vertical () const
bool	has_on (const Point_2< Kernel > &p) const
	A point is on r, iff it is equal to the source of r, or if it is in the interior of r.
bool	collinear_has_on (const Point_2< Kernel > &p) const
	checks if point p is on r.

Miscellaneous
Ray_2< Kernel >	transform (const Aff_transformation_2< Kernel > &t) const
	returns the ray obtained by applying t on the source and on the direction of r.

Constructor & Destructor Documentation

Ray_2()

template<typename Kernel >

CGAL::Ray_2< Kernel >::Ray_2	(	const Point_2< Kernel > &	p,
		const Point_2< Kernel > &	q
	)

introduces a ray r with source p and passing through point q.

Exactness

This construction is trivial and therefore always exact in Exact_predicates_inexact_constructions_kernel.

Member Function Documentation

collinear_has_on()

template<typename Kernel >

bool CGAL::Ray_2< Kernel >::collinear_has_on

(

const Point_2< Kernel > &

p

)

const

checks if point p is on r.

This function is faster than function has_on() if the precondition checking is disabled.

Precondition

p is on the supporting line of r.

point()

template<typename Kernel >

Point_2< Kernel > CGAL::Ray_2< Kernel >::point

(

const Kernel::FT

i

)

const

returns a point on r.

point(0) is the source, point(i), with i>0, is different from the source.

Precondition

i >= 0.

source()

template<typename Kernel >

Point_2< Kernel > CGAL::Ray_2< Kernel >::source

(

)

const

returns the source of r.

Exactness

This construction is trivial and therefore always exact in Exact_predicates_inexact_constructions_kernel.