590 lines
19 KiB
C++
590 lines
19 KiB
C++
// Copyright (c) 1997
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// Utrecht University (The Netherlands),
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// ETH Zurich (Switzerland),
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// INRIA Sophia-Antipolis (France),
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// Max-Planck-Institute Saarbruecken (Germany),
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// and Tel-Aviv University (Israel). All rights reserved.
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//
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// This file is part of CGAL (www.cgal.org)
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//
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// $URL: https://github.com/CGAL/cgal/blob/v5.1/Polygon/include/CGAL/Polygon_2.h $
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// $Id: Polygon_2.h 0779373 2020-03-26T13:31:46+01:00 Sébastien Loriot
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// SPDX-License-Identifier: LGPL-3.0-or-later OR LicenseRef-Commercial
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//
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//
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// Author(s) : Geert-Jan Giezeman <geert@cs.uu.nl>
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// Wieger Wesselink
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/*!
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\file Polygon_2.h
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*/
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#ifndef CGAL_POLYGON_2_H
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#define CGAL_POLYGON_2_H
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#include <CGAL/config.h>
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#include <vector>
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#include <list>
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#include <iterator>
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#include <CGAL/algorithm.h>
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#include <CGAL/circulator.h>
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#include <CGAL/enum.h>
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#include <CGAL/Aff_transformation_2.h>
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#include <CGAL/Polygon_2_algorithms.h>
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#include <CGAL/Polygon_2/Polygon_2_vertex_circulator.h>
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#include <CGAL/Polygon_2/Polygon_2_edge_iterator.h>
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#include <CGAL/Polygon_2/Polygon_2_edge_circulator.h>
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namespace CGAL {
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/// \ingroup PkgPolygon2Ref
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/// The class Polygon_2 implements polygons. The Polygon_2 is
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/// parameterized by a traits class and a container class. The latter
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/// can be any class that fulfills the requirements for an STL
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/// container, and has a function `resize()` that takes an std::size_t as argument
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/// . It defaults to the std::vector class.
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///
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/// \cgalHeading{Implementation}
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///
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/// The methods `is_simple()`, `is_convex()`, `orientation()`,
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/// `oriented_side()`, `bounded_side()`, `bbox()`, `area()`, `left_vertex()`,
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/// `right_vertex()`, `top_vertex()` and `bottom_vertex()` are all
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/// implemented using the algorithms on sequences of 2D points. See
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/// the corresponding global functions for information about which
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/// algorithms were used and what complexity they have.
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///
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template <class Traits_P, class Container_P
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= std::vector<typename Traits_P::Point_2> >
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class Polygon_2 {
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public:
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/// \name Types
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/// @{
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/// The traits type.
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typedef Traits_P Traits;
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/// The container type.
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typedef Container_P Container;
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/// The number type of the coordinates of the points of the polygon.
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typedef typename Traits_P::FT FT;
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/// The point type of the polygon.
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typedef typename Traits_P::Point_2 Point_2;
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/// The type of a segment between two points of the polygon.
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typedef typename Traits_P::Segment_2 Segment_2;
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/// @}
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typedef typename Container_P::difference_type difference_type;
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typedef typename Container_P::value_type value_type;
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typedef typename Container_P::pointer pointer;
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typedef typename Container_P::reference reference;
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typedef typename Container_P::const_reference const_reference;
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//-------------------------------------------------------//
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// this intermediary step is required by Sun C++ 4.1
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typedef typename Container_P::iterator iterator;
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typedef typename Container_P::const_iterator const_iterator;
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//-------------------------------------------------------//
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typedef typename Container::iterator Vertex_const_iterator;
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typedef Polygon_circulator<Container_P> Vertex_const_circulator;
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/// \name Iterators
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///
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/// The following types denote iterators that allow to traverse
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/// the vertices and edges of a polygon. Since
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/// a polygon can be viewed as a circular as well as a
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/// linear data structure both circulators and iterators are
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/// defined.
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///
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/// \note At least conceptually, the circulators and iterators are
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/// non-mutable. The enforcement depends on preprocessor flags.
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///
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/// \note The iterator category is in all cases bidirectional, except
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/// for Vertex_iterator, which has the same iterator category as
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/// `Container::iterator`. In fact all of them should have
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/// the same iterator category as `Container::iterator`. However,
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/// due to compiler problems this is currently not possible.
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///
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/// @{
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/// vertex iterator type
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typedef typename Container::iterator Vertex_iterator;
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//typedef typename Container::const_iterator Vertex_const_iterator; ??
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#ifdef DOXYGEN_RUNNING
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/// vertex circulator type
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typedef unspecified_type Vertex_circulator;
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/// edge circulator type
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typedef unspecified_type Edge_const_iterator;
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/// edge circular type
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typedef unspecified_type Edge_const_circulator;
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#else
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typedef Vertex_const_circulator Vertex_circulator;
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typedef Polygon_2_edge_iterator<Traits_P,Container_P> Edge_const_iterator;
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typedef Polygon_2_const_edge_circulator<Traits_P,
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Container_P> Edge_const_circulator;
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#endif // DOXYGEN_RUNNING
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/// @}
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/// \name Creation
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/// @{
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/// Creates an empty polygon.
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Polygon_2() : traits() {}
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/// Creates an empty polygon.
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Polygon_2(const Traits & p_traits) : traits(p_traits) {}
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/// Copy constructor.
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Polygon_2(const Polygon_2<Traits_P,Container_P>& polygon)
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: d_container(polygon.d_container), traits(polygon.traits) {}
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/// Creates a polygon with vertices from the sequence
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/// defined by the range \c [first,last).
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/// The value type of \c InputIterator must be \c Point_2.
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template <class InputIterator>
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Polygon_2(InputIterator first, InputIterator last,
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Traits p_traits = Traits())
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: d_container(), traits(p_traits)
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{
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// Sun STL switches off member templates for binary backward compat.
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std::copy(first, last, std::back_inserter(d_container));
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}
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#ifndef DOXYGEN_RUNNING
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Polygon_2& operator=(const Polygon_2&)=default;
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#endif
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/// @}
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/// \name Modifiers
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/// @{
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/// Acts as `*i = q`, except that that would be illegal because
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/// the iterator is not mutable.
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void set(Vertex_iterator i, const Point_2& q)
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{ *i = q; }
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/// \cond
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void set(Polygon_circulator<Container>const &i, const Point_2& q)
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{
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*i.mod_iterator() = q;
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}
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/// \endcond
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/// Inserts the vertex `q` before `i`. The return value points to
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/// the inserted vertex.
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Vertex_iterator insert(Vertex_iterator i, const Point_2& q)
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{
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return d_container.insert(i,q);
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}
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/// Inserts the vertex `q` before `i`. The return value points to
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/// the inserted vertex.
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Vertex_iterator insert(Vertex_circulator i, const Point_2& q)
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{
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return d_container.insert(i.mod_iterator(),q);
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}
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/// Inserts the vertices in the range `[first, last)`
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/// before `i`. The value type of points in the range
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/// `[first,last)` must be `Point_2`.
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template <class InputIterator>
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void insert(Vertex_iterator i,
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InputIterator first,
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InputIterator last)
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{ d_container.insert(i, first, last); }
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/// Inserts the vertices in the range `[first, last)`
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/// before `i`. The value type of points in the range
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/// `[first,last)` must be `Point_2`.
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template <class InputIterator>
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void insert(Vertex_circulator i,
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InputIterator first,
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InputIterator last)
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{ d_container.insert(i.mod_iterator(), first, last); }
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/// Has the same semantics as `p.insert(p.vertices_end(), q)`.
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void push_back(const Point_2& x)
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{ d_container.insert(d_container.end(), x); }
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/// Erases the vertex pointed to by `i`.
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Vertex_iterator erase(Vertex_iterator i)
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{
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return d_container.erase(i);
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}
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/// Erases the vertex pointed to by `i`.
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Vertex_circulator erase(Vertex_circulator i)
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{
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return Vertex_circulator(&d_container,
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d_container.erase(i.mod_iterator()));
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}
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/// Erases the vertices in the range `[first, last)`.
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Vertex_iterator erase(Vertex_iterator first, Vertex_iterator last)
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{
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return d_container.erase(first, last);
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}
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/// Erases the vertices in the range `[first, last)`.
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void clear()
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{
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d_container.clear();
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}
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/// Reverses the orientation of the polygon. The vertex pointed to
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/// by `p.vertices_begin()` remains the same.
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void reverse_orientation()
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{
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if (size() <= 1)
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return;
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typename Container_P::iterator i = d_container.begin();
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std::reverse(++i, d_container.end());
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}
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/// @}
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/// \name Access Functions
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/// The following methods of the class Polygon_2
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/// return circulators and iterators that allow to traverse the
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/// vertices and edges.
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/// @{
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/// Returns a constant iterator that allows to traverse the
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/// vertices of the polygon.
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Vertex_const_iterator vertices_begin() const
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{ return const_cast<Polygon_2&>(*this).d_container.begin(); }
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/// Returns the corresponding past-the-end iterator.
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Vertex_const_iterator vertices_end() const
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{ return const_cast<Polygon_2&>(*this).d_container.end(); }
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// Vertex_const_circulator vertices_circulator() const
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// { return Vertex_const_circulator(&d_container, d_container.begin()); }
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/// Returns a mutable circulator that allows to traverse the
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/// vertices of the polygon.
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Vertex_const_circulator vertices_circulator() const
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{
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Polygon_2& self = const_cast<Polygon_2&>(*this);
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return Vertex_const_circulator(&self.d_container,
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self.d_container.begin());
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}
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/// Returns a non-mutable iterator that allows to traverse the
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/// edges of the polygon.
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Edge_const_iterator edges_begin() const
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{ return Edge_const_iterator(&d_container, d_container.begin()); }
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/// Returns the corresponding past-the-end iterator.
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Edge_const_iterator edges_end() const
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{ return Edge_const_iterator(&d_container, d_container.end()); }
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/// Returns a non-mutable circulator that allows to traverse the
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/// edges of the polygon.
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Edge_const_circulator edges_circulator() const
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{ return Edge_const_circulator(vertices_circulator()); }
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/// @}
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/// \name Predicates
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/// @{
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/// Returns whether this is a simple polygon.
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bool is_simple() const
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{
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return is_simple_2(d_container.begin(),d_container.end(), traits);
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}
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/// Returns whether this is convex.
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bool is_convex() const
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{
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return is_convex_2(d_container.begin(),d_container.end(), traits);
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}
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/// Returns the orientation. If the number of vertices
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/// `p.size() < 3` then \c COLLINEAR is returned.
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/// \pre `p.is_simple()`.
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Orientation orientation() const
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{
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return orientation_2(d_container.begin(), d_container.end(), traits);
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}
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/// Returns `ON_POSITIVE_SIDE`, or `ON_NEGATIVE_SIDE`,
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/// or `ON_ORIENTED_BOUNDARY`, depending on where point
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/// `q` is.
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/// \pre `p.is_simple()`.
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Oriented_side oriented_side(const Point_2& value) const
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{
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return oriented_side_2(d_container.begin(), d_container.end(),
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value, traits);
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}
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/// Returns the symbolic constant `ON_BOUNDED_SIDE`,
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/// `ON_BOUNDARY` or `ON_UNBOUNDED_SIDE`,
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/// depending on where point `q` is. \pre
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/// `p.is_simple()`.
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Bounded_side bounded_side(const Point_2& value) const
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{
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CGAL_polygon_precondition(is_simple());
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return bounded_side_2(d_container.begin(), d_container.end(),
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value, traits);
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}
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/// Returns the smallest bounding box containing this polygon.
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Bbox_2 bbox() const
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{
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return bbox_2(d_container.begin(), d_container.end());
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}
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/// Returns the signed area of the polygon. This means that the
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/// area is positive for counter clockwise polygons and negative
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/// for clockwise polygons.
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FT area() const
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{
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return polygon_area_2(d_container.begin(), d_container.end(), traits);
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}
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/// Returns the leftmost vertex of the polygon with the smallest
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/// `x`-coordinate.
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Vertex_const_iterator left_vertex() const
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{
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Polygon_2 &self = const_cast<Polygon_2&>(*this);
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return left_vertex_2(self.d_container.begin(),
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self.d_container.end(), traits);
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}
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/// Returns the rightmost vertex of the polygon with the largest
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/// `x`-coordinate.
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Vertex_const_iterator right_vertex() const
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{
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Polygon_2 &self = const_cast<Polygon_2&>(*this);
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return right_vertex_2(self.d_container.begin(),
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self.d_container.end(), traits);
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}
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/// Returns topmost vertex of the polygon with the largest
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/// `y`-coordinate.
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Vertex_const_iterator top_vertex() const
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{
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Polygon_2 &self = const_cast<Polygon_2&>(*this);
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return top_vertex_2(self.d_container.begin(),
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self.d_container.end(), traits);
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}
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/// Returns the bottommost vertex of the polygon with the
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/// smallest `y`-coordinate.
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Vertex_const_iterator bottom_vertex() const
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{
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Polygon_2 &self = const_cast<Polygon_2&>(*this);
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return bottom_vertex_2(self.d_container.begin(),
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self.d_container.end(), traits);
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}
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/// @}
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/// \name Convenience Orientation Functions
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/// For convenience we provide the following Boolean functions:
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/// @{
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/// returns `orientation() == COUNTERCLOCKWISE`
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bool is_counterclockwise_oriented() const
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{ return orientation() == COUNTERCLOCKWISE; }
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/// returns `orientation() == CLOCKWISE`
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bool is_clockwise_oriented() const
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{ return orientation() == CLOCKWISE; }
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/// returns `orientation() == COLLINEAR`
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bool is_collinear_oriented() const
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{ return orientation() == COLLINEAR; }
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/// returns `oriented_side(q) == ON_POSITIVE_SIDE`
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bool has_on_positive_side(const Point_2& q) const
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{ return oriented_side(q) == ON_POSITIVE_SIDE; }
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/// returns `oriented_side(q) == ON_NEGATIVE_SIDE`
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bool has_on_negative_side(const Point_2& q) const
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{ return oriented_side(q) == ON_NEGATIVE_SIDE; }
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/// returns `bounded_side(q) == ON_BOUNDARY`
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bool has_on_boundary(const Point_2& q) const
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{ return bounded_side(q) == ON_BOUNDARY; }
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/// returns `bounded_side(q) == ON_BOUNDED_SIDE`
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bool has_on_bounded_side(const Point_2& q) const
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{ return bounded_side(q) == ON_BOUNDED_SIDE; }
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/// returns `bounded_side(q) == ON_UNBOUNDED_SIDE`
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bool has_on_unbounded_side(const Point_2& q) const
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{ return bounded_side(q) == ON_UNBOUNDED_SIDE; }
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/// @}
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/// \name Random Access Methods
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/// @{
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/// Returns a (const) reference to the `i`-th vertex.
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const Point_2& vertex(std::size_t i) const
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{
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CGAL_precondition( i < d_container.size() );
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return *(std::next(d_container.begin(), i));
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}
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/// Returns a (const) reference to the `i`-th vertex.
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const Point_2& operator[](std::size_t i) const
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{ return vertex(i); }
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/// Returns a reference to the `i`-th vertex.
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Point_2& vertex(std::size_t i)
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{
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CGAL_precondition( i < d_container.size() );
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return *(std::next(d_container.begin(), i));
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}
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/// Returns a reference to the `i`-th vertex.
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Point_2& operator[](std::size_t i)
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{ return vertex(i); }
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/// Returns the `i`-th edge.
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Segment_2 edge(std::size_t i) const
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{ return *(std::next(edges_begin(), i)); }
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/// @}
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/// \name Miscellaneous
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/// @{
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/// Returns the number of vertices of the polygon.
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std::size_t size() const
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{ return d_container.size(); }
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/// Returns `size() == 0`.
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bool is_empty() const
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{ return d_container.empty(); }
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/// Returns a const reference to the sequence of vertices of the polygon.
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const Container_P& container() const
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{ return d_container; }
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/// Returns a reference to the sequence of vertices of the polygon.
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Container_P& container()
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{ return d_container; }
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/// Returns an iterator to the first vertex of the polygon.
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typename Container_P::iterator begin()
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{
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return container().begin();
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}
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/// Returns an iterator to the element after the last vertex of the polygon.
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typename Container_P::iterator end()
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{
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return container().end();
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}
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/// Returns a const iterator to the first vertex of the polygon.
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const typename Container_P::const_iterator begin() const
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{
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return container().begin();
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}
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/// Returns a const iterator to the element after the last vertex of the polygon.
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const typename Container_P::const_iterator end() const
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{
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return container().end();
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}
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/// Resizes the container. Calls `container().resize(s)`.
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void resize(std::size_t s)
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{
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container().resize(s);
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}
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/// @}
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bool identical(const Polygon_2<Traits_P,Container_P> &q) const
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{ return this == &q; }
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Traits_P const &traits_member() const { return traits;}
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private:
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Container_P d_container;
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Traits_P traits;
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};
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/// \name Global Operators
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/// @{
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/// Test for equality: two polygons are equal iff there exists a
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/// cyclic permutation of the vertices of `p2` such that they are
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/// equal to the vertices of `p1`. Note that the template argument
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/// `%Container` of `p1` and `p2` may be different.
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/// \memberof Polygon_2
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template <class Traits_P, class Container1_P, class Container2_P>
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bool operator==( const Polygon_2<Traits_P,Container1_P> &p1,
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const Polygon_2<Traits_P,Container2_P> &p2 );
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/// Test for inequality.
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/// \memberof Polygon_2
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template <class Traits_P, class Container1_P, class Container2_P>
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inline
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bool
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operator!=(const Polygon_2<Traits_P,Container1_P> &p1,
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const Polygon_2<Traits_P,Container2_P> &p2);
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/// Returns the image of the polygon \c p under the transformation \c t.
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/// \memberof Polygon_2
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template <class Transformation, class Traits_P, class Container_P>
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Polygon_2<Traits_P,Container_P>
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transform(const Transformation& t, const Polygon_2<Traits_P,Container_P>& p);
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/// @} // global operators
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/// \name I/O
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|
/// The information output in the `std::iostream` is the number of points
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/// followed by the output of the coordinates of the vertices.
|
|
/// @{
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/// Reads a polygon from stream `is` and assigns it to `p`.
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/// \pre The extract operator must be defined for `Point_2`.
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/// \memberof Polygon_2
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|
template <class Traits_P, class Container_P>
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std::istream &operator>>(std::istream &is, Polygon_2<Traits_P,Container_P>& p);
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/// Inserts the polygon `p` into the stream `os`.
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|
/// \pre The insert operator must be defined for `Point_2`.
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|
/// \memberof Polygon_2
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|
template <class Traits_P, class Container_P>
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std::ostream &operator<<(std::ostream &os, const Polygon_2<Traits_P,Container_P>& p);
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|
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/// @} // IO
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|
|
} //namespace CGAL
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|
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//-----------------------------------------------------------------------//
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|
// implementation
|
|
//-----------------------------------------------------------------------//
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|
|
#include <CGAL/Polygon_2/Polygon_2_impl.h>
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|
|
|
namespace CGAL {
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|
|
|
template <class Traits_P, class Container1_P, class Container2_P>
|
|
inline
|
|
bool
|
|
operator!=(const Polygon_2<Traits_P,Container1_P> &x,
|
|
const Polygon_2<Traits_P,Container2_P> &y)
|
|
{
|
|
return !(x==y);
|
|
}
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|
|
|
} //namespace CGAL
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|
#endif
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