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2D Ray (CGAL_Ray_2)

Definition

An object r of the data type CGAL_Ray_2 is a directed straight ray in the two-dimensional Euclidean plane

E². It starts in a point called the source of r and goes to infinity.

#include <CGAL/Ray_2.h>

Creation

CGAL_Ray_2<R> r ( CGAL_Point_2<R> p, CGAL_Point_2<R> q);
introduces a ray r with source $p$ and passing through point $q$ .

CGAL_Ray_2<R> r ( CGAL_Point_2<R> p, CGAL_Direction_2<R> d);
introduces a ray r starting at source $p$ with direction $d$ .

Operations

bool r == h Test for equality: two rays are equal, iff they have the same source and the same direction.

bool r != h Test for inequality.

CGAL_Point_2<R> r.source () returns the source of r.

CGAL_Point_2<R> r.point ( int i) returns a point on r. point(0) is the source, point(i), with $i>0$ , is different from the source.
Precondition: $i >=0$ .

CGAL_Direction_2<R>
r.direction () returns the direction of r.

CGAL_Line_2<R> r.supporting_line ()
returns the line supporting r which has the same direction.

CGAL_Ray_2<R> r.opposite () returns the ray with the same source and the opposite direction.

Predicates

bool r.is_degenerate () ray r is degenerate, if the source and the second defining point fall together (that is if the direction is degenerate).

bool r.is_horizontal ()

bool r.is_vertical ()

bool r.has_on ( CGAL_Point_2<R> p)
A point is on r, iff it is equal to the source of r, or if it is in the interior of r.

bool r.collinear_has_on ( CGAL_Point_2<R> p)
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.

Miscellaneous

CGAL_Ray_2<R> r.transform ( CGAL_Aff_transformation_2<R> t)
returns the ray obtained by applying $t$ on the source and on the direction of r.

Next: Class declaration of CGAL_Segment_2<R>

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The CGAL Project. Wed, January 20, 1999.

CGAL_Ray_2<R> r ( CGAL_Point_2<R> p, CGAL_Point_2<R> q);
	introduces a ray r with source $p$ and passing through point $q$ .
CGAL_Ray_2<R> r ( CGAL_Point_2<R> p, CGAL_Direction_2<R> d);
	introduces a ray r starting at source $p$ with direction $d$ .

bool	r == h	Test for equality: two rays are equal, iff they have the same source and the same direction.
bool	r != h	Test for inequality.
CGAL_Point_2<R>	r.source ()	returns the source of r.
CGAL_Point_2<R>	r.point ( int i)	returns a point on r. point(0) is the source, point(i), with $i>0$ , is different from the source. Precondition: $i >=0$ .
CGAL_Direction_2<R>
	r.direction ()	returns the direction of r.
CGAL_Line_2<R>	r.supporting_line ()
		returns the line supporting r which has the same direction.
CGAL_Ray_2<R>	r.opposite ()	returns the ray with the same source and the opposite direction.

bool	r.is_degenerate ()	ray r is degenerate, if the source and the second defining point fall together (that is if the direction is degenerate).
bool	r.is_horizontal ()
bool	r.is_vertical ()
bool	r.has_on ( CGAL_Point_2<R> p)
		A point is on r, iff it is equal to the source of r, or if it is in the interior of r.
bool	r.collinear_has_on ( CGAL_Point_2<R> p)
		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.

CGAL_Ray_2<R>	r.transform ( CGAL_Aff_transformation_2<R> t)
		returns the ray obtained by applying $t$ on the source and on the direction of r.