Version 5.0 The LEDA User Manual

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