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// Copyright (c) 2003,2004,2005,2006 INRIA Sophia-Antipolis (France).
// All rights reserved.
//
// This file is part of CGAL (www.cgal.org).
// You can redistribute it and/or modify it under the terms of the GNU
// General Public License as published by the Free Software Foundation,
// either version 3 of the License, or (at your option) any later version.
//
// Licensees holding a valid commercial license may use this file in
// accordance with the commercial license agreement provided with the software.
//
// This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
// WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
//
// $URL$
// $Id$
// SPDX-License-Identifier: GPL-3.0+
//
//
// Author(s) : Menelaos Karavelas <mkaravel@iacm.forth.gr>
#ifndef CGAL_SEGMENT_DELAUNAY_GRAPH_2_ARE_PARALLEL_C2_H
#define CGAL_SEGMENT_DELAUNAY_GRAPH_2_ARE_PARALLEL_C2_H
#include <CGAL/license/Segment_Delaunay_graph_2.h>
#include <CGAL/Segment_Delaunay_graph_2/basic.h>
#include <CGAL/determinant.h>
namespace CGAL {
namespace SegmentDelaunayGraph_2 {
//-----------------------------------------------------------------------
// are parallel
//-----------------------------------------------------------------------
template< class K >
class Are_parallel_C2
{
public:
typedef typename K::Site_2 Site_2;
typedef typename K::Boolean Boolean;
typedef Boolean result_type;
typedef Site_2 argument_type;
private:
typedef typename K::Segment_2 Segment_2;
typedef typename K::FT FT;
private:
Boolean predicate(const Site_2& p, const Site_2& q) const {
CGAL_precondition( p.is_segment() && q.is_segment() );
Segment_2 s1 = p.segment();
Segment_2 s2 = q.segment();
FT x1 = s1.source().x(),
y1 = s1.source().y(),
x2 = s1.target().x(),
y2 = s1.target().y(),
x3 = s2.source().x(),
y3 = s2.source().y(),
x4 = s2.target().x(),
y4 = s2.target().y();
FT det = determinant<FT>(x2 - x1, x4 - x3,
y2 - y1, y4 - y3);
return ( CGAL::sign(det) == CGAL::ZERO );
}
public:
result_type operator()(const Site_2& p, const Site_2& q) const
{
return predicate(p, q);
}
};
} //namespace SegmentDelaunayGraph_2
} //namespace CGAL
#endif // CGAL_SEGMENT_DELAUNAY_GRAPH_2_ARE_PARALLEL_C2_H
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