/Sweep_line_2/include/CGAL/Sweep_line_2_algorithms.h

// Copyright (c) 2005,2006,2007,2009,2010,2011 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
// 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.
//
// $URL$
// $Id$
//
//
// Author(s): Baruch Zukerman <baruchzu@post.tau.ac.il>
//            Efi Fogel       <efif@post.tau.ac.il>
//            (based on old version by Tali Zvi)

#ifndef CGAL_SWEEP_LINE_2_ALGORITHMS_H
#define CGAL_SWEEP_LINE_2_ALGORITHMS_H

/*!
 * \file Definition of the sweep-line related functions.
 */

#include <CGAL/Sweep_line_2.h>
#include <CGAL/Sweep_line_2/Sweep_line_2_visitors.h>

#include <CGAL/Segment_2.h>
#include <CGAL/Arr_segment_traits_2.h>
#include <CGAL/Arr_polyline_traits_2.h>
#include <CGAL/Arr_conic_traits_2.h>
#include <CGAL/Arr_rational_function_traits_2.h>
#include <CGAL/Arr_circle_segment_traits_2.h>
#include <CGAL/Arr_linear_traits_2.h>
#include <CGAL/Arr_rat_arc/Rational_arc_d_1.h>

namespace CGAL {

template <typename Curve>
struct Default_arr_traits
{};

template <typename Kernel>
struct Default_arr_traits<CGAL::Segment_2<Kernel> >
{
  typedef CGAL::Arr_segment_traits_2<Kernel>                            Traits;
};

template <typename Kernel>
struct Default_arr_traits<CGAL::Arr_segment_2<Kernel> >
{
  typedef CGAL::Arr_segment_traits_2<Kernel>                            Traits;
};

template <typename SubcurveTraits>
struct Default_arr_traits<CGAL::internal::Polycurve_2
                          <SubcurveTraits, typename SubcurveTraits::Point_2> >
{
  typedef CGAL::Arr_polyline_traits_2<SubcurveTraits>                   Traits;
};

template <typename Rat_kernel_, class Alg_kernel_, class Nt_traits_>
struct Default_arr_traits<CGAL::_Conic_arc_2<Rat_kernel_, Alg_kernel_,
                                             Nt_traits_> >
{
  typedef CGAL::Arr_conic_traits_2<Rat_kernel_, Alg_kernel_, Nt_traits_>
                                                                        Traits;
};

template <typename Algebraic_kernel_>
struct Default_arr_traits<CGAL::Arr_rational_arc::Rational_arc_d_1<Algebraic_kernel_> >
{
  typedef CGAL::Arr_rational_function_traits_2<Algebraic_kernel_>       Traits;
};

template <typename Kernel_, bool Filter_>
struct Default_arr_traits<CGAL::_Circle_segment_2<Kernel_, Filter_> >
{
  typedef CGAL::Arr_circle_segment_traits_2<Kernel_, Filter_>           Traits;
};

template <typename Kernel>
struct Default_arr_traits<CGAL::Arr_linear_object_2<Kernel> >
{
  typedef CGAL::Arr_linear_traits_2<Kernel>                             Traits;
};

/*!
 * Compute all intersection points induced by a range of input curves.
 * The intersections are calculated using the sweep-line algorithm.
 * \param begin An input iterator for the first curve in the range.
 * \param end A input past-the-end iterator for the range.
 * \param points Output: An output iterator for the intersection points
 *                       induced by the input curves.
 * \param report_endpoints If (true), the end points of the curves are also
 *                         reported as intersection points.
 * \pre The value-type of CurveInputIterator is Traits::Curve_2, and the
 *      value-type of OutputIterator is Traits::Point_2.
 */
template <class CurveInputIterator, class OutputIterator, class Traits>
OutputIterator compute_intersection_points (CurveInputIterator curves_begin,
                                            CurveInputIterator curves_end,
                                            OutputIterator points,
                                            bool report_endpoints,
                                            Traits &tr)
{
  // Define the sweep-line types:
  typedef Sweep_line_points_visitor<Traits,OutputIterator>  Visitor;
  typedef Sweep_line_2< Traits,
                        Sweep_line_points_visitor<Traits, OutputIterator> >
                                                            Sweep_line;

  // Perform the sweep and obtain the intersection points.
  Visitor     visitor (points, report_endpoints);
  Sweep_line  sweep_line (&tr, &visitor);
  visitor.sweep(curves_begin, curves_end);

  return (visitor.output_iterator());
}

template <class CurveInputIterator, class OutputIterator>
OutputIterator compute_intersection_points (CurveInputIterator curves_begin,
                                            CurveInputIterator curves_end,
                                            OutputIterator points,
                                            bool report_endpoints = false)
{
  typedef typename std::iterator_traits<CurveInputIterator>::value_type  Curve;

  typename Default_arr_traits<Curve>::Traits   traits;

  return (compute_intersection_points(curves_begin, curves_end, points,
                                      report_endpoints, traits));
}

/*!
 * Compute all x-monotone subcurves that are disjoint in their interiors
 * induced by a range of input curves.
 * The subcurves are calculated using the sweep-line algorithm.
 * \param begin An input iterator for the first curve in the range.
 * \param end A input past-the-end iterator for the range.
 * \param points Output: An output iterator for the subcurve.
 * \param mult_overlaps If (true), the overlapping subcurve will be reported
 *                      multiple times.
 * \pre The value-type of CurveInputIterator is Traits::Curve_2, and the
 *      value-type of OutputIterator is Traits::X_monotone_curve_2.
 */
template <class CurveInputIterator, class OutputIterator, class Traits>
OutputIterator compute_subcurves (CurveInputIterator curves_begin,
                                  CurveInputIterator curves_end,
                                  OutputIterator subcurves,
                                  bool mult_overlaps, Traits &tr)
{
  // Define the sweep-line types:
  typedef Sweep_line_subcurves_visitor<Traits, OutputIterator>  Visitor;
  typedef Sweep_line_2<Traits,
                       Sweep_line_subcurves_visitor<Traits, OutputIterator> >
                                                                Sweep_line;

  // Perform the sweep and obtain the subcurves.
  Visitor     visitor (subcurves, mult_overlaps);
  Sweep_line  sweep_line (&tr, &visitor);
  visitor.sweep(curves_begin, curves_end);

  return (visitor.output_iterator());
}


template <class CurveInputIterator, class OutputIterator>
OutputIterator compute_subcurves (CurveInputIterator curves_begin,
                                  CurveInputIterator curves_end,
                                  OutputIterator subcurves,
                                  bool mult_overlaps = false)
{
  typedef typename std::iterator_traits<CurveInputIterator>::value_type  Curve;
  typename Default_arr_traits<Curve>::Traits   m_traits;
  return compute_subcurves(curves_begin, curves_end, subcurves, mult_overlaps,
                           m_traits);
}

/*!
 * Determine if there occurs an intersection between any pair of curves in
 * a given range.
 * \param begin An input iterator for the first curve in the range.
 * \param end A input past-the-end iterator for the range.
 * \return (true) if any pair of curves intersect; (false) otherwise.
 */
template <class CurveInputIterator, class Traits>
bool do_curves_intersect (CurveInputIterator curves_begin,
                          CurveInputIterator curves_end, Traits &tr)
{
  // Define the sweep-line types:
  typedef Sweep_line_do_curves_x_visitor<Traits>      Visitor;
  typedef Sweep_line_2<Traits, Sweep_line_do_curves_x_visitor<Traits> >
    Sweep_line;

  // Perform the sweep and obtain the subcurves.
  Visitor     visitor;
  Sweep_line  sweep_line (&tr, &visitor);
  visitor.sweep(curves_begin, curves_end);

  return (visitor.found_intersection());
}


template <class CurveInputIterator>
bool do_curves_intersect (CurveInputIterator curves_begin,
                          CurveInputIterator curves_end)
{
  typedef typename std::iterator_traits<CurveInputIterator>::value_type  Curve;

  typename Default_arr_traits<Curve>::Traits   m_traits;
  return do_curves_intersect (curves_begin, curves_end, m_traits);
}

} //namespace CGAL

#endif