Version 5.0 The LEDA User Manual

14.22 Real Triangles ( real triangle )
1. Definition
An instance t of the data type real triangle is an oriented triangle in the two-dimensional
plane. A triangle splits the plane into one bounded and one unbounded region. If the
triangle is positively oriented, the bounded region is to the left of it, if it is negatively
oriented, the unbounded region is to the left of it. A triangle t is called degenerate, if the
3 vertices of t are collinear.
#include < LEDA/geo/real triangle.h >
2. Types
real triangle :: coord type
real triangle :: point type
the coordinate type (real).
the point type (real point).
3. Creation
real triangle t;
introduces a variable t of type real triangle. t is initialized to
the empty triangle.
real triangle t(const real point& p, const real point& q, const real point& r);
introduces a variable t of type real triangle. t is initialized to
the triangle [p, q, r].
real triangle t(real x1 , real y1 , real x2 , real y2 , real x3 , real y3 );
real triangle t(const triangle& t1 , int prec = 0);
real triangle t(const rat triangle& t1 );
introduces a variable t of type real triangle. t is initialized to
the triangle [(x1, y1), (x2, y2), (x3, y3)].
introduces a variable t of type real triangle initialized to the
triangle t 1 . (The second argument is for compatibility with
rat triangle.)
introduces a variable t of type real triangle initialized to the
triangle t 1 .
4. Operations
real point t.point1( ) returns the first vertex of triangle t.
real point t.point2( ) returns the second vertex of triangle t.