Version 5.0 The LEDA User Manual

14.12 Rational Rays ( rat ray )
1. Definition
An instance r of the data type rat ray is a directed straight ray defined by two points
with rational coordinates in the two-dimensional plane.
#include < LEDA/geo/rat ray.h >
2. Types
rat ray :: coord type
rat ray :: point type
rat ray :: float type
the coordinate type (rational).
the point type (rat point).
the corresponding floatin-point type (ray).
3. Creation
rat ray r(const rat point& p, const rat point& q);
rat ray r(const rat segment& s);
introduces a variable r of type rat ray. r is initialized to the
ray starting at point p and passing through point q.
Precondition: p ≠ q.
introduces a variable r of type rat ray. r is initialized to the
(rat ray(s.source(), s.target()).
Precondition: s is nontrivial.
rat ray r(const rat point& p, const rat vector& v);
introduces a variable r of type rat ray.
rat r ay(p, p + v).
r is initialized to
rat ray r;
introduces a variable r of type rat ray.
rat ray r(const ray& r1 , int prec = rat point :: default precision);
introduces a variable r of type rat ray. r is initialized to the
ray obtained by approximating the two defining points of r 1 .
4. Operations
ray r.to float( ) returns a floating point approximation of r.
void r.normalize( ) simplifies the homogenous representation
by calling point1 ( ).normalize( ) and
point2 ( ).normlize( ).