cgal/Packages/Cartesian_kernel/include/CGAL/Cartesian/Ray_2.h

// ======================================================================
//
// Copyright (c) 2000 The CGAL Consortium
//
// This software and related documentation is part of an INTERNAL release
// of the Computational Geometry Algorithms Library (CGAL). It is not
// intended for general use.
//
// ----------------------------------------------------------------------
//
// release       :
// release_date  :
//
// file          : include/CGAL/Cartesian/Ray_2.h
// revision      : $Revision$
// revision_date : $Date$
// author(s)     : Andreas Fabri, Herve Bronnimann
// coordinator   : INRIA Sophia-Antipolis (Mariette.Yvinec@sophia.inria.fr)
//
// ======================================================================

#ifndef CGAL_CARTESIAN_RAY_2_H
#define CGAL_CARTESIAN_RAY_2_H

#include <CGAL/Cartesian/redefine_names_2.h>

CGAL_BEGIN_NAMESPACE

template < class R_ >
class RayC2 CGAL_ADVANCED_KERNEL_PARTIAL_SPEC
  : public R_::Ray_handle_2
{
public:
  typedef R_                                    R;
  typedef typename R::FT                        FT;
  typedef typename R::RT                        RT;

  typedef typename R::Ray_handle_2              Ray_handle_2_;
  typedef typename Ray_handle_2_::element_type   Ray_ref_2;

#ifndef CGAL_CFG_NO_ADVANCED_KERNEL
  typedef RayC2<R,Cartesian_tag>                Self;
  typedef typename R::Point_2                   Point_2;
  typedef typename R::Vector_2                  Vector_2;
  typedef typename R::Direction_2               Direction_2;
  typedef typename R::Line_2                    Line_2;
  typedef typename R::Triangle_2                Triangle_2;
  typedef typename R::Segment_2                 Segment_2;
  typedef typename R::Iso_rectangle_2           Iso_rectangle_2;
  typedef typename R::Aff_transformation_2      Aff_transformation_2;
  typedef typename R::Circle_2                  Circle_2;
#else
  typedef RayC2<R>                              Self;
  typedef typename R::Point_2_base              Point_2;
  typedef typename R::Vector_2_base             Vector_2;
  typedef typename R::Direction_2_base          Direction_2;
  typedef typename R::Line_2_base               Line_2;
  typedef typename R::Triangle_2_base           Triangle_2;
  typedef typename R::Segment_2_base            Segment_2;
  typedef typename R::Iso_rectangle_2_base      Iso_rectangle_2;
  typedef typename R::Aff_transformation_2_base Aff_transformation_2;
  typedef typename R::Circle_2_base             Circle_2;
#endif

  RayC2()
    : Ray_handle_2_(Ray_ref_2()) {}

  RayC2(const Point_2 &sp, const Point_2 &secondp)
    : Ray_handle_2_(Ray_ref_2(sp, secondp)) {}

  RayC2(const Point_2 &sp, const Direction_2 &d)
    : Ray_handle_2_(Ray_ref_2(sp, sp + d.to_vector())){}

  bool        operator==(const Self &r) const;
  bool        operator!=(const Self &r) const;

  const Point_2 &     start() const;
  const Point_2 &     source() const
  {
      return Ptr()->e0;
  }
  Point_2     point(int i) const;
  const Point_2 &     second_point() const
  {
      return Ptr()->e1;
  }

  Direction_2 direction() const;
  Line_2      supporting_line() const;
  Self        opposite() const;

  Self        transform(const Aff_transformation_2 &t) const
  {
    return Self(t.transform(source()), t.transform(second_point()));
  }

  bool        is_horizontal() const;
  bool        is_vertical() const;
  bool        is_degenerate() const;
  bool        has_on(const Point_2 &p) const;
  bool        collinear_has_on(const Point_2 &p) const;
};

#ifdef CGAL_CFG_TYPENAME_BUG
#define typename
#endif

template < class R >
CGAL_KERNEL_INLINE
bool
RayC2<R CGAL_CTAG>::operator==(const RayC2<R CGAL_CTAG> &r) const
{
  if (identical(r))
      return true;
  return source() == r.source() && direction() == r.direction();
}

template < class R >
inline
bool
RayC2<R CGAL_CTAG>::operator!=(const RayC2<R CGAL_CTAG> &r) const
{
  return !(*this == r);
}

template < class R >
inline
const typename RayC2<R CGAL_CTAG>::Point_2 &
RayC2<R CGAL_CTAG>::start() const
{
  return source();
}

template < class R >
CGAL_KERNEL_INLINE
typename RayC2<R CGAL_CTAG>::Point_2
RayC2<R CGAL_CTAG>::point(int i) const
{
  CGAL_kernel_precondition( i >= 0 );
  if (i == 0) return source();
  if (i == 1) return second_point();
  return source() + (second_point() - source()) * FT(i);
}

template < class R >
inline
typename RayC2<R CGAL_CTAG>::Direction_2
RayC2<R CGAL_CTAG>::direction() const
{
  return Direction_2( second_point() - source() );
}

template < class R >
inline
typename RayC2<R CGAL_CTAG>::Line_2
RayC2<R CGAL_CTAG>::supporting_line() const
{
  return Line_2(*this);
}

template < class R >
inline
RayC2<R CGAL_CTAG>
RayC2<R CGAL_CTAG>::opposite() const
{
  return RayC2<R CGAL_CTAG>( source(), - direction() );
}

template < class R >
CGAL_KERNEL_INLINE
bool RayC2<R CGAL_CTAG>::is_horizontal() const
{
  return y_equal(source(), second_point());
}

template < class R >
CGAL_KERNEL_INLINE
bool RayC2<R CGAL_CTAG>::is_vertical() const
{
  return x_equal(source(), second_point());
}

template < class R >
CGAL_KERNEL_INLINE
bool RayC2<R CGAL_CTAG>::is_degenerate() const
{
  return source() == second_point();
}

template < class R >
CGAL_KERNEL_INLINE
bool
RayC2<R CGAL_CTAG>::has_on(const typename RayC2<R CGAL_CTAG>::Point_2 &p) const
{
  return p == source()
      || collinear(source(), p, second_point())
      && Direction_2(p - source()) == direction();
}

template < class R >
CGAL_KERNEL_MEDIUM_INLINE
bool
RayC2<R CGAL_CTAG>::
collinear_has_on(const typename RayC2<R CGAL_CTAG>::Point_2 &p) const
{
    switch(compare_x(source(), second_point())){
    case SMALLER:
        return compare_x(source(), p) != LARGER;
    case LARGER:
        return compare_x(p, source()) != LARGER;
    default:
        switch(compare_y(source(), second_point())){
        case SMALLER:
            return compare_y(source(), p) != LARGER;
        case LARGER:
            return compare_y(p, source()) != LARGER;
        default:
            return true; // p == source()
        }
    }
}

#ifndef CGAL_NO_OSTREAM_INSERT_RAYC2
template < class R >
std::ostream &
operator<<(std::ostream &os, const RayC2<R CGAL_CTAG> &r)
{
    switch(os.iword(IO::mode)) {
    case IO::ASCII :
        return os << r.source() << ' ' << r.direction();
    case IO::BINARY :
        return os << r.source() << r.direction();
    default:
        return os << "RayC2(" << r.source() <<  ", " << r.direction() << ")";
    }
}
#endif // CGAL_NO_OSTREAM_INSERT_RAYC2

#ifndef CGAL_NO_ISTREAM_EXTRACT_RAYC2
template < class R >
std::istream &
operator>>(std::istream &is, RayC2<R CGAL_CTAG> &r)
{
    typename RayC2<R CGAL_CTAG>::Point_2 p;
    typename RayC2<R CGAL_CTAG>::Direction_2 d;

    is >> p >> d;

    if (is)
	r = RayC2<R CGAL_CTAG>(p, d);
    return is;
}
#endif // CGAL_NO_ISTREAM_EXTRACT_RAYC2

#ifdef CGAL_CFG_TYPENAME_BUG
#undef typename
#endif

CGAL_END_NAMESPACE

#endif // CGAL_CARTESIAN_RAY_2_H