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// Copyright (c) 1999
// Utrecht University (The Netherlands),
// ETH Zurich (Switzerland),
// INRIA Sophia-Antipolis (France),
// Max-Planck-Institute Saarbruecken (Germany),
// and Tel-Aviv University (Israel). All rights reserved.
//
// This file is part of CGAL (www.cgal.org)
//
// $URL: https://github.com/CGAL/cgal/blob/v6.1/Homogeneous_kernel/include/CGAL/Homogeneous/VectorH2.h $
// $Id: include/CGAL/Homogeneous/VectorH2.h b26b07a1242 $
// SPDX-License-Identifier: LGPL-3.0-or-later OR LicenseRef-Commercial
//
//
// Author(s) : Stefan Schirra
#ifndef CGAL_HOMOGENEOUS_VECTOR_2_h
#define CGAL_HOMOGENEOUS_VECTOR_2_h
#include <CGAL/Origin.h>
#include <CGAL/array.h>
#include <CGAL/Kernel_d/Cartesian_const_iterator_d.h>
#include <CGAL/Handle_for.h>
namespace CGAL {
template < class R_ >
class VectorH2
{
typedef VectorH2<R_> Self;
typedef typename R_::FT FT;
typedef typename R_::RT RT;
typedef typename R_::Point_2 Point_2;
typedef typename R_::Segment_2 Segment_2;
typedef typename R_::Ray_2 Ray_2;
typedef typename R_::Line_2 Line_2;
typedef typename R_::Direction_2 Direction_2;
typedef typename R_::Vector_2 Vector_2;
typedef std::array<RT, 3> Rep;
typedef typename R_::template Handle<Rep>::type Base;
typedef Rational_traits<FT> Rat_traits;
Base base;
public:
typedef const FT Cartesian_coordinate_type;
typedef const RT& Homogeneous_coordinate_type;
typedef Cartesian_const_iterator_d<typename Rep::const_iterator> Cartesian_const_iterator;
typedef R_ R;
VectorH2() {}
template < typename Tx, typename Ty >
VectorH2(const Tx & x, const Ty & y,
std::enable_if_t<std::is_convertible_v<Tx, RT> &&
std::is_convertible_v<Ty, RT>>* = 0)
: base(CGAL::make_array<RT>(x, y, RT(1))) {}
VectorH2(const FT& x, const FT& y)
: base(CGAL::make_array<RT>(
Rat_traits().numerator(x) * Rat_traits().denominator(y),
Rat_traits().numerator(y) * Rat_traits().denominator(x),
Rat_traits().denominator(x) * Rat_traits().denominator(y)))
{
CGAL_kernel_assertion(hw() > 0);
}
VectorH2(const RT& x, const RT& y, const RT& w )
: base( w >= RT(0) ? CGAL::make_array( x, y, w)
: CGAL::make_array<RT>(-x, -y, -w) ) {}
const Self&
rep() const
{
return static_cast<const Self& >(*this);
}
typename R::Boolean operator==( const VectorH2<R>& v) const;
typename R::Boolean operator!=( const VectorH2<R>& v) const;
typename R::Boolean operator==( const Null_vector&) const;
typename R::Boolean operator!=( const Null_vector& v) const;
const RT & hx() const { return CGAL::get_pointee_or_identity(base)[0]; };
const RT & hy() const { return CGAL::get_pointee_or_identity(base)[1]; };
const RT & hw() const { return CGAL::get_pointee_or_identity(base)[2]; };
FT x() const { return FT(hx()) / FT(hw()); };
FT y() const { return FT(hy()) / FT(hw()); };
FT cartesian(int i) const;
const RT & homogeneous(int i) const;
FT operator[](int i) const;
Cartesian_const_iterator cartesian_begin() const
{
return make_cartesian_const_iterator_begin(CGAL::get_pointee_or_identity(base).begin(),
std::prev(CGAL::get_pointee_or_identity(base).end()));
}
Cartesian_const_iterator cartesian_end() const
{
return make_cartesian_const_iterator_end(std::prev(CGAL::get_pointee_or_identity(base).end()));
}
int dimension() const;
Direction_2 direction() const;
Vector_2 perpendicular(const Orientation& o ) const;
// Vector_2 operator+(const VectorH2 &v) const;
Vector_2 operator-(const VectorH2 &v) const;
Vector_2 operator-() const;
Vector_2 opposite() const;
FT squared_length() const;
// Vector_2 operator/(const RT &f) const;
//Vector_2 operator/(const FT &f) const;
// undocumented:
VectorH2(const Direction_2 & dir)
: base ( dir) {}
VectorH2(const Point_2 & p)
: base ( p) {}
};
template < class R >
inline
typename R::Boolean
VectorH2<R>::operator==( const Null_vector&) const
{ return (hx() == RT(0)) && (hy() == RT(0)); }
template < class R >
inline
typename R::Boolean
VectorH2<R>::operator!=( const Null_vector& v) const
{ return !(*this == v); }
template < class R >
CGAL_KERNEL_INLINE
typename R::Boolean
VectorH2<R>::operator==( const VectorH2<R>& v) const
{
return ( (hx() * v.hw() == v.hx() * hw() )
&&(hy() * v.hw() == v.hy() * hw() ) );
}
template < class R >
inline
typename R::Boolean
VectorH2<R>::operator!=( const VectorH2<R>& v) const
{ return !(*this == v); } /* XXX */
template < class R >
CGAL_KERNEL_INLINE
typename VectorH2<R>::FT
VectorH2<R>::cartesian(int i) const
{
CGAL_kernel_precondition( (i==0 || i==1) );
if (i==0)
return x();
return y();
}
template < class R >
CGAL_KERNEL_INLINE
const typename VectorH2<R>::RT &
VectorH2<R>::homogeneous(int i) const
{
CGAL_kernel_precondition( (i>=0) && (i<=2) );
return CGAL::get_pointee_or_identity(base)[i];
}
template < class R >
inline
typename VectorH2<R>::FT
VectorH2<R>::operator[](int i) const
{ return cartesian(i); }
template < class R >
inline
int
VectorH2<R>::dimension() const
{ return 2; }
template < class R >
CGAL_KERNEL_INLINE
typename VectorH2<R>::Direction_2
VectorH2<R>::direction() const
{ return Direction_2(hx(), hy()); }
template < class R >
inline
typename VectorH2<R>::Vector_2
VectorH2<R>::operator-() const
{ return VectorH2<R>(- hx(), - hy(), hw() ); }
template < class R >
inline
typename VectorH2<R>::Vector_2
VectorH2<R>::opposite() const
{ return VectorH2<R>(- hx(), - hy(), hw() ); }
template <class R>
CGAL_KERNEL_INLINE
typename VectorH2<R>::Vector_2
VectorH2<R>::operator-(const VectorH2<R>& v) const
{
return VectorH2<R>( hx()*v.hw() - v.hx()*hw(),
hy()*v.hw() - v.hy()*hw(),
hw()*v.hw() );
}
template <class R>
CGAL_KERNEL_INLINE
typename VectorH2<R>::FT
VectorH2<R>::squared_length() const
{
typedef typename R::FT FT;
return
FT( CGAL_NTS square(hx()) + CGAL_NTS square(hy()) ) /
FT( CGAL_NTS square(hw()) );
}
template < class R >
CGAL_KERNEL_INLINE
typename R::Vector_2
VectorH2<R>::perpendicular(const Orientation& o) const
{
CGAL_kernel_precondition(o != COLLINEAR);
if (o == COUNTERCLOCKWISE)
return typename R::Vector_2(-hy(), hx(), hw());
else
return typename R::Vector_2(hy(), -hx(), hw());
}
} //namespace CGAL
#endif // CGAL_HOMOGENEOUS_VECTOR_2_h
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