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Added an example of Cartesian_converter specialization for Lazy_alpha_NT 

Needed due to the weird point type that Projection traits use
This commit is contained in:
Mael Rouxel-Labbé 2017-06-14 16:48:25 +02:00
parent 68d3a3eabf
commit 7f44271325
1 changed files with 40 additions and 4 deletions
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44
Alpha_shapes_2/test/Alpha_shapes_2/test_alpha_projection_traits.cpp
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@ -1,6 +1,12 @@
#include <CGAL/Simple_cartesian.h> #include <CGAL/Simple_cartesian.h>
#include <CGAL/Filtered_kernel.h> #include <CGAL/Filtered_kernel.h>
#include <CGAL/Cartesian_converter.h>
#include <CGAL/Delaunay_triangulation_2.h>
#include <CGAL/Projection_traits_xy_3.h>
#include <CGAL/algorithm.h> #include <CGAL/algorithm.h>
#include <cstdio> #include <cstdio>
#include <cstring> #include <cstring>
#include <iostream> #include <iostream>
@ -8,10 +14,6 @@
#include <vector> #include <vector>
#include <list> #include <list>
#include <CGAL/Delaunay_triangulation_2.h>
#include <CGAL/Alpha_shape_2.h>
#include <CGAL/Projection_traits_xy_3.h>
typedef double coord_type; typedef double coord_type;
typedef CGAL::Simple_cartesian<coord_type> SC; typedef CGAL::Simple_cartesian<coord_type> SC;
@ -21,6 +23,40 @@ typedef CGAL::Projection_traits_xy_3<FK> K;
typedef K::Point_2 Point; typedef K::Point_2 Point;
typedef K::Segment_2 Segment; typedef K::Segment_2 Segment;
// -------------------------------------------------------------------
// Since K::Point_2 is here in fact CGAL::Point_3<FK>, the basic Cartesian_converter
// cannot be used (and thus ExactAlphaComparisonTag can't be set to 'true') because
// it does not know how to convert from CGAL::Point_3<FK> to CGAL::Point_2<EK>.
// Thus, we must provide a specialization for our case
namespace CGAL {
template < class K2, class C >
class Cartesian_converter<FK, K2, C>
{
public:
typedef CGAL::Projection_traits_xy_3<FK> Source_kernel;
typedef K2 Target_kernel;
typedef C Number_type_converter;
typedef typename Source_kernel::Point_2 SP2;
typedef typename Target_kernel::Point_2 TP2;
TP2 operator()(const SP2& p) const
{
return TP2(c(p.x()), c(p.y()));
}
private:
C c;
};
} // namespace CGAL
// The include is only here because the partial specialization above must be before
#include <CGAL/Alpha_shape_2.h>
//ExactAlphaComparisonTag is false //ExactAlphaComparisonTag is false
typedef K Gt; typedef K Gt;
typedef CGAL::Alpha_shape_vertex_base_2<Gt> Vb; typedef CGAL::Alpha_shape_vertex_base_2<Gt> Vb;