cgal/Arrangement_2/include/CGAL/Arr_trapezoid_ric_point_location.h

// Copyright (c) 2005  Tel-Aviv University (Israel).
// All rights reserved.
//
// This file is part of CGAL (www.cgal.org); you may redistribute it under
// the terms of the Q Public License version 1.0.
// See the file LICENSE.QPL 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.
//
// $URL$
// $Id$
// 
//
// Author(s)     : Idit Haran   <haranidi@post.tau.ac.il>
//                 (based on old version by Oren Nechushtan and Iddo Hanniel)

#ifndef CGAL_ARR_TRAPEZOID_RIC_POINT_LOCATION_H
#define CGAL_ARR_TRAPEZOID_RIC_POINT_LOCATION_H

/*! \file
 * Definition of the Arr_trapezoid_ric_point_location<Arrangement> template.
 */

#include <CGAL/Arrangement_2/Arr_traits_adaptor_2.h>
#include <CGAL/Arr_point_location/Trapezoidal_decomposition_2.h>
#include <CGAL/Arr_point_location/Td_traits.h>

CGAL_BEGIN_NAMESPACE

/*!
 * \class
 * Mapping of an x-monotone curve to the halfedge associated with it.
 */
template <class Arrangement_>
class PL_X_curve_plus: public Arrangement_::X_monotone_curve_2
{
public:

  typedef Arrangement_                                  Arrangement_2;
  typedef typename Arrangement_2::Traits_2              Traits_2;
  typedef typename Arrangement_2::Halfedge_handle       Halfedge_handle;
  typedef typename Arrangement_2::X_monotone_curve_2    X_monotone_curve_2;

protected:
  //Data members
  Halfedge_handle       parent;    // The halfedge associated with the curve.

public:

  /*! Default constructor. */
  PL_X_curve_plus() : 
    X_monotone_curve_2(),
    parent() 
  {}

  /*! Constructor from a curve and a halfedge. */
  PL_X_curve_plus (const X_monotone_curve_2& cv,
		   const Halfedge_handle& p) : 
    X_monotone_curve_2(cv), 
    parent(p) 
  {}

  /*! Constrtuctor from a halfedge only. */
  PL_X_curve_plus(const Halfedge_handle& p) : 
    X_monotone_curve_2(p->curve()),
    parent(p)
  {}

  /*! Constrtuctor from a curve only. */
  PL_X_curve_plus(const X_monotone_curve_2 &cv) : 
    X_monotone_curve_2(cv),
    parent() 
  {}

  /*! Get the parent halfedge. */
  Halfedge_handle get_parent() const
  {
    return (parent);
  }
};


/*! \class
 * A class that answers point-location and queries
 * on a planar arrangement using the trapezoid_ric algorithm.
 * The Arrangement parameter corresponds to an arrangement instantiation.
 */
template <class Arrangement_>
class Arr_trapezoid_ric_point_location : public Arr_observer <Arrangement_>
{
public:

  typedef Arrangement_                                  Arrangement_2;
  typedef typename Arrangement_2::Traits_2              Traits_2;

  typedef typename Arrangement_2::Vertex_const_handle   Vertex_const_handle;
  typedef typename Arrangement_2::Halfedge_const_handle Halfedge_const_handle;
  typedef typename Arrangement_2::Face_const_handle     Face_const_handle;
  typedef typename Arrangement_2::Vertex_handle		Vertex_handle;
  typedef typename Arrangement_2::Halfedge_handle	Halfedge_handle;
  typedef typename Arrangement_2::Face_handle		Face_handle;
  typedef typename Arrangement_2::Halfedge_iterator	Halfedge_iterator;

  typedef typename Arrangement_2::Vertex_const_iterator Vertex_const_iterator;
  typedef typename Arrangement_2::Edge_const_iterator   Edge_const_iterator;
  typedef typename Arrangement_2::Hole_const_iterator  Hole_const_iterator;
  typedef typename Arrangement_2::Halfedge_const_iterator  
                                       Halfedge_const_iterator;
  typedef typename Arrangement_2::Halfedge_around_vertex_const_circulator 
                                       Halfedge_around_vertex_const_circulator;
  typedef typename Arrangement_2::Ccb_halfedge_const_circulator 
                                       Ccb_halfedge_const_circulator;
  typedef typename Arrangement_2::Ccb_halfedge_circulator 
                                       Ccb_halfedge_circulator;
  typedef typename Arrangement_2::Isolated_vertex_const_iterator
                                       Isolated_vertex_const_iterator;

  typedef typename Traits_2::Point_2                      Point_2;
  typedef typename Traits_2::X_monotone_curve_2           X_monotone_curve_2;

  typedef std::list<Halfedge_const_handle>                Edge_list;
  typedef typename Edge_list::iterator                    Std_edge_iterator;

  typedef PL_X_curve_plus<Arrangement_2>                  X_curve_plus;

  typedef Arr_traits_basic_adaptor_2<Traits_2>            Traits_adaptor_2;
  typedef CGAL::Td_traits<Traits_adaptor_2, X_curve_plus> Td_traits;
  typedef Trapezoidal_decomposition_2<Td_traits>    Trapezoidal_decomposition;
  typedef std::vector<Halfedge_const_handle>        Halfedge_handle_container;
  typedef typename Halfedge_handle_container::iterator 
                                                    Halfedge_handle_iterator;
 
protected:

  typedef Trapezoidal_decomposition             TD;

  // Data members:
  const Traits_adaptor_2    *traits;  // Its associated traits object.

  TD                        td;       // instance of trapezoidal decomposition
  const Td_traits*          td_traits;// instance of the TD traits
                                  //for the notification functions
  X_monotone_curve_2        m_curve_before_split; 
  X_monotone_curve_2        m_curve_before_merge1;
  X_monotone_curve_2        m_curve_before_merge2;


public:

  /*! Default constructor. */
  Arr_trapezoid_ric_point_location (bool rebuild = true) : 
    traits (NULL),
    td_traits(NULL)
  {
    td.set_needs_update(rebuild);
  }

  /*! Constructor given an arrangement. */
  Arr_trapezoid_ric_point_location (const Arrangement_2& arr) :
    Arr_observer<Arrangement_2> (const_cast<Arrangement_2 &>(arr))
  {
    traits = static_cast<const Traits_adaptor_2*> (arr.get_traits());
    td_traits = new Td_traits(*traits);
    td.init_traits(td_traits);

    build_trapezoid_ric();
  }

  /*! Destructor. */
  ~Arr_trapezoid_ric_point_location () 
  {
    if (td_traits)
      delete (td_traits);
  }
 
  /*!
   * Locate the arrangement feature containing the given point.
   * \param p The query point.
   * \return An object representing the arrangement feature containing the
   *         query point. This object is either a Face_const_handle or a
   *         Halfedge_const_handle or a Vertex_const_handle.
   */
  Object locate (const Point_2& p) const;

  /*!
   * Locate the arrangement feature which a upward vertical ray emanating from
   * the given point hits.
   * \param p The query point.
   * \return An object representing the arrangement feature the ray hits.
   *         This object is either an empty object or a
   *         Halfedge_const_handle or a Vertex_const_handle.
   */
  Object ray_shoot_up (const Point_2& p) const
  {
    return (_vertical_ray_shoot (p, true));
  }

  /*!
   * Locate the arrangement feature which a downward vertical ray emanating
   * from the given point hits.
   * \param p The query point.
   * \return An object representing the arrangement feature the ray hits.
   *         This object is either an empty object or a
   *         Halfedge_const_handle or a Vertex_const_handle.
   */
  Object ray_shoot_down (const Point_2& p) const
  {
    return (_vertical_ray_shoot (p, false));
  }

  /// \name Notification functions, inherited and overloaded from the
  //        base observer.
  //@{

  virtual void before_assign (const Arrangement_2& arr)
  {
    clear_trapezoid_ric();
	  traits = static_cast<const Traits_adaptor_2*> (arr.get_traits());
  }

  virtual void after_assign ()
  { 
    build_trapezoid_ric();
  }

  virtual void before_clear ()
  {
    clear_trapezoid_ric ();
  }

  virtual void after_clear (Face_handle /* u */)
  {
    build_trapezoid_ric();
  }

  virtual void before_attach (const Arrangement_2& arr)
  {
    clear_trapezoid_ric();
	  traits = static_cast<const Traits_adaptor_2*> (arr.get_traits());
    td_traits = new Td_traits(*traits);
    td.init_traits(td_traits);
  }

  virtual void after_attach ()
  {
    build_trapezoid_ric();
  }

  virtual void before_detach ()
  {
    clear_trapezoid_ric();
  }

  virtual void after_create_edge (Halfedge_handle e)
  {
    // Postcondition: h->curve() with a reference back to h
    // is inserted into TD.
    td.insert(X_curve_plus(e));
  }

  //TODO IDIT OREN: what can be done in order to avoid the need 
  //to save the original curve is to find the common endpoint of the 
  //two new halfedges, locate it in the trapezoid in order to find the 
  //curve it lies on, which is the curve that was split, and then remove 
  //this curve.
  virtual void before_split_edge (Halfedge_handle e,
				  Vertex_handle /* v */,
                                  const X_monotone_curve_2& /* c1 */,
                                  const X_monotone_curve_2& /* c2 */)
  {
    //save this curve for the "after" function.
    m_curve_before_split = e->curve();
  }

  virtual void after_split_edge (Halfedge_handle e1,
                                 Halfedge_handle e2)
  {
    td.split_edge(X_curve_plus(m_curve_before_split),
                  X_curve_plus(e1),
                  X_curve_plus(e2));
  }

  //TODO IDIT OREN: create a merged X_curve_plus withput a halfedge,
  // and in the "after" function update the halfedge.
  // think ...
  virtual void before_merge_edge (Halfedge_handle e1,
                                  Halfedge_handle e2,
                                  const X_monotone_curve_2& /* c */)
  {
    //save the curves for the "after" function.
    m_curve_before_merge1 = e1->curve();
    m_curve_before_merge2 = e2->curve();
  }

  virtual void after_merge_edge (Halfedge_handle e)
  {
    td.merge_edge(X_curve_plus(m_curve_before_merge1),
                  X_curve_plus(m_curve_before_merge2),
                  X_curve_plus(e));
  }

  virtual void before_remove_edge (Halfedge_handle e)
  {
    //called before combinatoric deletion
    td.remove(X_curve_plus(e));
  }
  //@}

public:

#ifdef CGAL_TD_DEBUG
  void debug()
  {
    td.debug();
  }
#endif

protected:

  /*! Clear the trapezoidal decomposition. */
  inline void clear_trapezoid_ric ()
  { 
    td.clear();
  }

  /*! Construct the trapezoidal decomposition. */
  void build_trapezoid_ric ()
  {
    td.clear();

    Halfedge_handle_container c; 
    Edge_const_iterator         eit;
    Halfedge_const_handle    hh;
    Arrangement_2 *arr = this->arrangement();

    for (eit = arr->edges_begin(); eit != arr->edges_end(); ++eit)
    {
      hh = eit;
      c.push_back(hh);
    }

    // Random shuffle of the halfedges.
    std::random_shuffle (c.begin (), c.end ());

    Halfedge_handle_iterator cit;
    Halfedge_handle          he;

    for (cit = c.begin(); cit < c.end(); cit++)
    {
      hh = *cit;
      he = arr->non_const_handle(hh);
      td.insert(X_curve_plus(he));
    }

  }

  /*!
   * Locate the arrangement feature which a vertical ray emanating from the
   * given point hits, considering isolated vertices.
   * \param p The query point.
   * \param shoot_up Indicates whether the ray is directed upward or downward.
   * \return An object representing the arrangement feature the ray hits.
   *         This object is either a Halfedge_const_handle,
   *         a Vertex_const_handle or an empty object.
   */
  Object _vertical_ray_shoot (const Point_2& p, bool shoot_up) const;

  /*! In vertical ray shoot, when the closest halfedge is found
   * (or unbounded face)
   * we check the isolated vertices inside the face to check whether there
   * is an isolated vertex right above/below the query point.
   */ 
  Object _check_isolated_for_vertical_ray_shoot
                             (Halfedge_const_handle halfedge_found, 
                              const Point_2& p, bool shoot_up) const;
};

CGAL_END_NAMESPACE

// The member-function definitions can be found under:
#include <CGAL/Arr_point_location/Arr_trapezoid_ric_pl_functions.h>

#endif