ForwardIterator first,
ForwardIterator last,
Traits traits)
Computes the signed area of the polygon defined by the range of points
first ... last.
The sign is positive for counterclockwise polygons, negative for
clockwise polygons. If the polygon is not simple, the area is not well defined.
Requirements
Traits is a model of the concept
PolygonTraits_2
.
Only the following members of this traits class are used:
Compute_area_2 : Computes the signed area of the
oriented triangle defined by 3 Point_2 passed as arguments.
FT
compute_area_2_object
ForwardIterator::value_type should be Traits::Point_2,