Real Rays ( real_ray )

Definition

An instance r of the data type real_ray is a directed straight ray in the two-dimensional plane.

#include < LEDA/geo/real_ray.h >

Types

real_ray::coord_type	the coordinate type (real).
real_ray::point_type	the point type (real_point).

Creation

real_ray	r(const real_point& p, const real_point& q)
		introduces a variable r of type real_ray. r is initialized to the ray starting at point p and passing through point q.
real_ray	r(const real_segment& s)	introduces a variable r of type real_ray. r is initialized to real_ray(s.source(),s.target()).
real_ray	r(const real_point& p, const real_vector& v)
		introduces a variable r of type real_ray. r is initialized to real_ray(p,p+v).
real_ray	r	introduces a variable r of type real_ray. r is initialized to the ray starting at the origin with direction 0.
real_ray	r(const ray& r1, int prec = 0)
		introduces a variable r of type real_ray initialized to the ray r1. (The second argument is for compatibility with rat_ray.)
real_ray	r(const rat_ray& r1)	introduces a variable r of type real_ray initialized to the ray r1.

Operations

real_point	r.source()	returns the source of r.
real_point	r.point1()	returns the source of r.
real_point	r.point2()	returns a point on r different from r.source().
bool	r.is_vertical()	returns true iff r is vertical.
bool	r.is_horizontal()	returns true iff r is horizontal.
real	r.slope()	returns the slope of the straight line underlying r. Precondition r is not vertical.
bool	r.intersection(const real_ray& s, real_point& inter)
		if r and s intersect in a single point this point is assigned to inter and the result is true, otherwise the result is false.
bool	r.intersection(const real_segment& s, real_point& inter)
		if r and s intersect in a single point this point is assigned to inter and the result is true, otherwise the result is false.
real_ray	r.translate(real dx, real dy)
		returns r translated by vector (dx, dy).
real_ray	r.translate(const real_vector& v)
		returns r translated by vector v Precondition v.dim() = 2.
real_ray	r + const real_vector& v	returns r translated by vector v.
real_ray	r - const real_vector& v	returns r translated by vector - v.
real_ray	r.rotate90(const real_point& q, int i=1)
		returns r rotated about q by an angle of i x 90 degrees. If i > 0 the rotation is counter-clockwise otherwise it is clockwise.
real_ray	r.reflect(const real_point& p, const real_point& q)
		returns r reflected across the straight line passing through p and q.
real_ray	r.reflect(const real_point& p)
		returns r reflected across point p.
real_ray	r.reverse()	returns r reversed.
bool	r.contains(const real_point& )
		decides whether r contains p.
bool	r.contains(const real_segment& )
		decides whether r contains s.

Non-Member Functions

int	orientation(const real_ray& r, const real_point& p)
		computes orientation(a, b, p) (see the manual page of real_point), where a $\not=$b and a and b appear in this order on ray r.
int	cmp_slopes(const real_ray& r1, const real_ray& r2)
		returns compare(slope(r1), slope(r2)) where slope(ri) denotes the slope of the straight line underlying ri.