Version 5.0 The LEDA User Manual

14.4 Straight Lines ( line )
1. Definition
An instance l of the data type line is a directed straight line in the two-dimensional plane.
The angle between a right oriented horizontal line and l is called the direction of l.
#include < LEDA/geo/line.h >
2. Types
line :: coord type
line :: point type
the coordinate type (double).
the point type (point).
3. Creation
line l(const point& p, const point& q);
introduces a variable l of type line. l is initialized to the line
passing through points p and q directed form p to q.
line l(const segment& s); introduces a variable l of type line. l is initialized to the line
supporting segment s.
line l(const ray& r);
introduces a variable l of type line. l is initialized to the line
supporting ray r.
line l(const point& p, const vector& v);
line l(const point& p, double alpha);
introduces a variable l of type line. l is initialized to the line
passing through points p and p + v.
introduces a variable l of type line. l is initialized to the line
passing through point p with direction alpha.
line l;
introduces a variable l of type line. l is initialized to the line
passing through the origin with direction 0.
4. Operations
point l.point1( ) returns a point on l.
point l.point2( ) returns a second point on l.
segment l.seg( ) returns a segment on l.
double l.angle(const line& g) returns the angle between l and g, i.e.,
g.direction() − l.direction().