// Copyright (c) 1999 Utrecht University (The Netherlands),
// ETH Zurich (Switzerland), Freie Universitaet Berlin (Germany),
// INRIA Sophia-Antipolis (France), Martin-Luther-University Halle-Wittenberg
// (Germany), Max-Planck-Institute Saarbruecken (Germany), RISC Linz (Austria),
// and Tel-Aviv University (Israel). 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 Lesser General Public License as
// published by the Free Software Foundation; version 2.1 of the License.
// See the file LICENSE.LGPL distributed with CGAL.
//
// 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.
//
// $Source: /CVSROOT/CGAL/Packages/H2/include/CGAL/Homogeneous/CircleH2.h,v $
// $Revision: 1.17 $ $Date: 2004/06/20 18:09:03 $
// $Name: $
//
// Author(s) : Sven Schoenherr
// Stefan Schirra
#ifndef CGAL_CIRCLEH2_H
#define CGAL_CIRCLEH2_H
#include <CGAL/utility.h>
#include <CGAL/Interval_arithmetic.h>
CGAL_BEGIN_NAMESPACE
template <class R_>
class CircleH2
{
typedef typename R_::FT FT;
typedef typename R_::RT RT;
typedef typename R_::Point_2 Point_2;
typedef typename R_::Aff_transformation_2 Aff_transformation_2;
typedef Triple<Point_2, FT, Orientation> Rep;
typedef typename R_::template Handle<Rep>::type Base;
Base base;
public:
typedef R_ R;
CircleH2() {}
CircleH2(const Point_2& p, const Point_2& q, const Point_2& r)
{
Orientation o = CGAL::orientation( p, q, r);
CGAL_kernel_precondition( o != COLLINEAR);
Point_2 cp = circumcenter( p, q, r);
FT sq_r = squared_distance( p, cp);
base = Rep(cp, sq_r, o);
}
CircleH2(const Point_2& p, const Point_2& q, const Orientation& o)
{
CGAL_kernel_precondition( o != COLLINEAR);
if ( p != q)
{
Point_2 cp = midpoint( p, q);
FT sq_r = squared_distance( cp, p);
base = Rep(cp, sq_r, o);
}
else
base = Rep(p, FT( 0), o);
}
CircleH2(const Point_2& cp, const FT& squared_radius,
const Orientation& o)
{
CGAL_precondition( ( ! CGAL_NTS is_negative( squared_radius)) &&
( o != COLLINEAR ) );
base = Rep(cp, squared_radius, o);
}
Bbox_2
bbox() const;
CircleH2<R>
orthogonal_transform(const Aff_transformation_2&) const;
const Point_2 &
center() const;
Orientation
orientation() const;
const FT &
squared_radius() const;
CircleH2<R>
opposite() const;
Oriented_side
oriented_side(const Point_2& ) const;
Bounded_side
bounded_side(const Point_2& ) const;
bool operator==( const CircleH2<R>& ) const;
bool operator!=( const CircleH2<R>& ) const;
bool has_on_positive_side(const Point_2& ) const;
bool has_on_negative_side(const Point_2& ) const;
bool has_on_boundary( const Point_2& ) const;
bool has_on_bounded_side( const Point_2& ) const;
bool has_on_unbounded_side(const Point_2&) const;
bool is_degenerate() const;
// bool oriented_equal( const CircleH2<R>& ) const;
// bool unoriented_equal( const CircleH2<R>& ) const;
};
template <class R>
inline
const typename CircleH2<R>::Point_2 &
CircleH2<R>::center() const
{ return get(base).first; }
template <class R>
inline
const typename CircleH2<R>::FT &
CircleH2<R>::squared_radius() const
{ return get(base).second; }
template <class R>
CGAL_KERNEL_INLINE
CircleH2<R>
CircleH2<R>::opposite() const
{
return CircleH2<R>( center(),
squared_radius(),
CGAL::opposite( orientation() ) );
}
template <class R>
inline
Orientation
CircleH2<R>::orientation() const
{ return get(base).third; }
template <class R>
CGAL_KERNEL_INLINE
Oriented_side
CircleH2<R>::oriented_side( const typename CircleH2<R>::Point_2& p) const
{
FT sq_dist = squared_distance( p, center() );
FT sq_rad = squared_radius();
Comparison_result vgl = CGAL_NTS compare( sq_dist, sq_rad );
Oriented_side rel_pos = (vgl == LARGER ) ?
ON_NEGATIVE_SIDE :
( (vgl == SMALLER ) ?
ON_POSITIVE_SIDE :
ON_ORIENTED_BOUNDARY);
if (orientation() == POSITIVE)
{ return rel_pos; }
else // NEGATIVE
{ return CGAL::opposite( rel_pos ); }
}
template <class R>
CGAL_KERNEL_INLINE
bool
CircleH2<R>::has_on_positive_side(const typename CircleH2<R>::Point_2& p) const
{
if ( orientation() == POSITIVE )
{ return (has_on_bounded_side(p) ); }
else
{ return (has_on_unbounded_side(p) ); }
}
template <class R>
CGAL_KERNEL_INLINE
bool
CircleH2<R>::has_on_boundary(const typename CircleH2<R>::Point_2& p) const
{
FT sq_dist = squared_distance( p, center() );
FT sq_rad = squared_radius();
return ( sq_dist == sq_rad );
}
template <class R>
CGAL_KERNEL_INLINE
bool
CircleH2<R>::has_on_negative_side( const typename CircleH2<R>::Point_2&p) const
{
if ( orientation() == NEGATIVE )
{
return (has_on_bounded_side(p) );
}
else
{
return (has_on_unbounded_side(p) );
}
}
template <class R>
CGAL_KERNEL_INLINE
Bounded_side
CircleH2<R>::bounded_side(const typename CircleH2<R>::Point_2& p) const
{
FT sq_dist = squared_distance( p, center() );
FT sq_rad = squared_radius();
Comparison_result vgl = CGAL_NTS compare( sq_dist, sq_rad );
return (vgl == LARGER ) ? ON_UNBOUNDED_SIDE :
( (vgl == SMALLER ) ?
ON_BOUNDED_SIDE :
ON_BOUNDARY);
}
template <class R>
CGAL_KERNEL_INLINE
bool
CircleH2<R>::has_on_bounded_side(const typename CircleH2<R>::Point_2& p) const
{
FT sq_dist = squared_distance( p, center() );
FT sq_rad = squared_radius();
return ( sq_dist < sq_rad );
}
template <class R>
CGAL_KERNEL_INLINE
bool
CircleH2<R>::has_on_unbounded_side(const typename CircleH2<R>::Point_2&p) const
{
FT sq_dist = squared_distance( p, center() );
FT sq_rad = squared_radius();
return ( sq_rad < sq_dist );
}
template <class R>
inline
bool
CircleH2<R>::is_degenerate() const
{ return ( squared_radius() == FT(0) ); }
template <class R>
CGAL_KERNEL_MEDIUM_INLINE
Bbox_2
CircleH2<R>::bbox() const
{
Bbox_2 b = center().bbox();
Interval_nt<> x (b.xmin(), b.xmax());
Interval_nt<> y (b.ymin(), b.ymax());
Interval_nt<> sqr = CGAL_NTS to_interval(squared_radius());
Interval_nt<> r = CGAL::sqrt(sqr);
Interval_nt<> minx = x-r;
Interval_nt<> maxx = x+r;
Interval_nt<> miny = y-r;
Interval_nt<> maxy = y+r;
return Bbox_2(minx.inf(), miny.inf(), maxx.sup(), maxy.sup());
}
template <class R>
CGAL_KERNEL_INLINE
CircleH2<R>
CircleH2<R>::
orthogonal_transform(const typename CircleH2<R>::Aff_transformation_2& t) const
{
typename R::Vector_2 vec( RT(1), RT(0) ); // unit vector
vec = vec.transform(t); // transformed
FT sq_scale = FT( vec*vec ); // squared scaling factor
if ( t.is_even() )
{
return CircleH2<R>(t.transform(center() ),
sq_scale * squared_radius(),
orientation() );
}
else
{
return CircleH2<R>(t.transform(center() ),
sq_scale * squared_radius(),
CGAL::opposite( orientation()) );
}
}
template <class R>
CGAL_KERNEL_INLINE
bool
CircleH2<R>::operator==(const CircleH2<R>& c) const
{
return ( center() == c.center() )
&&( squared_radius() == c.squared_radius() )
&&( orientation() == c.orientation() );
}
template <class R>
inline
bool
CircleH2<R>::operator!=(const CircleH2<R>& c) const
{ return !(*this == c); }
#ifndef CGAL_NO_OSTREAM_INSERT_CIRCLEH2
template < class R >
std::ostream &operator<<(std::ostream &os, const CircleH2<R> &c)
{
switch(os.iword(IO::mode))
{
case IO::ASCII :
os << c.center() << ' ' << c.squared_radius() << ' '
<< static_cast<int>(c.orientation());
break;
case IO::BINARY :
os << c.center();
write(os, c.squared_radius());
write(os, static_cast<int>(c.orientation()));
break;
default:
os << "CircleH2(" << c.center() << ", " << c.squared_radius() ;
if (c.orientation() == CLOCKWISE) {
os << ", clockwise)";
} else if (c.orientation() == COUNTERCLOCKWISE) {
os << ", counterclockwise)";
} else {
os << ", collinear)";
}
break;
}
return os;
}
#endif // CGAL_NO_OSTREAM_INSERT_CIRCLEH2
#ifndef CGAL_NO_ISTREAM_EXTRACT_CIRCLEH2
template < class R >
std::istream& operator>>(std::istream &is, CircleH2<R> &c)
{
typename R::Point_2 center;
typename R::FT squared_radius;
int o;
switch(is.iword(IO::mode))
{
case IO::ASCII :
is >> center >> squared_radius >> o;
break;
case IO::BINARY :
is >> center;
read(is, squared_radius);
is >> o;
break;
default:
std::cerr << "" << std::endl;
std::cerr << "Stream must be in ascii or binary mode" << std::endl;
break;
}
c = CircleH2<R>(center, squared_radius, static_cast<Orientation>(o));
return is;
}
#endif // CGAL_NO_ISTREAM_EXTRACT_CIRCLEH2
CGAL_END_NAMESPACE
#endif // CGAL_CIRCLEH2_H
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