Version 5.0 The LEDA User Manual

4. Operations
point s.start( ) returns the source point of segment s.
point s.end( ) returns the target point of segment s.
double s.xcoord1( ) returns the x-coordinate of s.source().
double s.xcoord2( ) returns the x-coordinate of s.target().
double s.ycoord1( ) returns the y-coordinate of s.source().
double s.ycoord2( ) returns the y-coordinate of s.target().
double s.dx( ) returns the xcoord2 − xcoord1.
double s.dy( ) returns the ycoord2 − ycoord1.
double s.slope( ) returns the slope of s.
Precondition: s is not vertical.
double s.sqr length( ) returns the square of the length of s.
double s.length( ) returns the length of s.
vector s.to vector( ) returns the vector s.target( ) − s.source( ).
double s.direction( ) returns the direction of s as an angle in the intervall [0, 2π).
double s.angle( ) returns s.direction().
double s.angle(const segment& t)
bool s.is trivial( ) returns true if s is trivial.
bool s.is vertical( ) returns true iff s is vertical.
returns the angle between s and t, i.e., t.direction() -
s.direction().
bool s.is horizontal( ) returns true iff s is horizontal.
int s.orientation(const point& p)
computes orientation(s.source(), s.target(), p) (see below).
double s.x proj(double y) returns p.xcoord(), where p ∈ line(s) with p.ycoord() = y.
Precondition: s is not horizontal.
double s.y proj(double x) returns p.ycoord(), where p ∈ line(s) with p.xcoord() = x.
Precondition: s is not vertical.
double s.y abs( ) returns the y-abscissa of line(s), i.e., s.y proj(0).
Precondition: s is not vertical.