CGAL 4.12  2D Alpha Shapes

The concept WeightedAlphaShapeTraits_2
describes the requirements for the geometric traits class of the underlying regular triangulation of a weighted alpha shape.
In addition to the requirements described in the concept RegularTriangulationTraits_2
, the geometric traits class of a regular triangulation plugged in a basic alpha shapes provides the following.
All models of Kernel
.
Projection traits such as CGAL::Projection_traits_xy_3<K>
.
CGAL::Exact_predicates_inexact_constructions_kernel
(recommended kernel) Types  
typedef unspecified_type  FT 
A coordinate type. More...  
Creation  
Only a default constructor is required. Note that further constructors can be provided.  
AlphaShapeTraits_2 ()  
A default constructor.  
Constructions by function objects  
Compute_squared_radius_smallest_orthogonal_circle_2  compute_squared_radius_smallest_orthogonal_circle_2_object () 
Returns an object, which has to be able to compute the squared radius of the orthogonal circle of the points p0, p1, p2 or the squared radius of the smallest orthogonal circle of the points p0, p1 , as FT .  
Predicate by function object  
Power_side_of_bounded_power_circle_2  power_side_of_bounded_power_circle_2_object () 
Returns an object, which has to be able to compute the relative position of the point test to the smallest orthogonal circle of the points p0, p1 .  
A coordinate type.
The type must provide a copy constructor, assignment, comparison operators, negation, multiplication, division and allow the declaration and initialization with a small integer constant (cf. requirements for number types). An obvious choice would be coordinate type of the point class.