Version 5.0 The LEDA User Manual

POLYGON
POLYGON
P (const list& pl,
CHECK TYPE check = POLYGON :: WEAKLY SIMPLE,
RESPECT TYPE respect orientation =
POLYGON :: RESPECT ORIENTATION );
introduces a variable P of type POLYGON . P is initialized
to the polygon with vertex sequence pl. If respect orientation
is DISREGARD ORIENTATION, the positive orientation is
chosen.
Precondition: If check is SIMPLE, pl must define a simple
polygon, and if check is WEAKLY SIMPLE, pl must define
a weakly simple polygon. If no test is to performed, the second
argument has to be set to NO CHECK. The constants
NO CHECK, SIMPLE, and WEAKLY SIMPLE are part of
a local enumeration type CHECK TYPE.
P (const polygon& Q, int prec = rat point :: default precision);
introduces a variable P of type POLYGON . P is initialized
to a rational approximation of the (floating point) polygon Q
of coordinates with denominator at most prec. If prec is zero,
the implementation chooses prec large enough such that there
is no loss of precision in the conversion.
4. Operations
polygon P.to float( ) returns a floating point approximation of P .
void P.normalize( ) simplifies the homogenous representation by
calling p.normalize( ) for every vertex p of
P .
bool P.is simple( ) tests whether P is simple or not.
bool P.is weakly simple( ) tests whether P is weakly simple or not.
bool P.is weakly simple(list& L)
POLYGON :: CHECK TYPE P.check simplicity( )
as above, returns all proper points of intersection
in L.
returns the CHECK TYPE of P . The result
can be SIMPLE, WEAKLY SIMPLE or
NOT WEAKLY SIMPLE.
bool P.is convex( ) returns true if P is convex, false otherwise.
const list& P.vertices( )
returns the sequence of vertices of P in counterclockwise
ordering.