161 lines
6.3 KiB
C++
161 lines
6.3 KiB
C++
// Copyright (c) 2006 Tel-Aviv University (Israel).
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// 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/Minkowski_sum_2/include/CGAL/offset_polygon_2.h $
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// $Id: offset_polygon_2.h 254d60f 2019-10-19T15:23:19+02:00 Sébastien Loriot
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// SPDX-License-Identifier: GPL-3.0-or-later OR LicenseRef-Commercial
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//
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// Author(s) : Ron Wein <wein_r@yahoo.com>
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#ifndef CGAL_OFFSET_POLYGON_H
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#define CGAL_OFFSET_POLYGON_H
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#include <CGAL/license/Minkowski_sum_2.h>
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#include <CGAL/Minkowski_sum_2/Exact_offset_base_2.h>
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#include <CGAL/Minkowski_sum_2/Offset_conv_2.h>
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#include <CGAL/Minkowski_sum_2/Offset_decomp_2.h>
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namespace CGAL {
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/*!
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* Compute the offset of a given simple polygon by a given radius,
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* using the convolution method.
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* Note that as the input polygon may not be convex, its offset may not be
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* simply connected. The result is therefore represented as a polygon with
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* holes.
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* \param pgn The polygon.
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* \param r The offset radius.
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* \return The offset polygon.
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*/
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template <class ConicTraits, class Container>
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typename Gps_traits_2<ConicTraits>::Polygon_with_holes_2
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offset_polygon_2 (const Polygon_2<typename ConicTraits::Rat_kernel,
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Container>& pgn,
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const typename ConicTraits::Rat_kernel::FT& r,
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const ConicTraits& )
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{
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typedef Exact_offset_base_2<ConicTraits, Container> Base;
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typedef Offset_by_convolution_2<Base> Exact_offset_2;
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typedef typename Exact_offset_2::Offset_polygon_2 Offset_polygon_2;
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Base base;
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Exact_offset_2 exact_offset (base);
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Offset_polygon_2 offset_bound;
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std::list<Offset_polygon_2> offset_holes;
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exact_offset (pgn, r,
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offset_bound, std::back_inserter(offset_holes));
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return (typename Gps_traits_2<ConicTraits>::Polygon_with_holes_2
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(offset_bound, offset_holes.begin(), offset_holes.end()));
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}
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/*!
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* Compute the offset of a given polygon with holes by a given radius,
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* using the convolution method.
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* The result is represented as a polygon with holes whose edges are line
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* segments and circular arcs.
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* \param pwh The polygon with holes.
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* \param r The offset radius.
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* \pre The polygon is bounded (has a valid outer boundary).
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* \return The offset polygon.
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*/
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template <class ConicTraits, class Container>
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typename Gps_traits_2<ConicTraits>::Polygon_with_holes_2
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offset_polygon_2 (const Polygon_with_holes_2<typename ConicTraits::Rat_kernel,
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Container>& pwh,
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const typename ConicTraits::Rat_kernel::FT& r,
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const ConicTraits& )
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{
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typedef Exact_offset_base_2<ConicTraits, Container> Base;
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typedef Offset_by_convolution_2<Base> Exact_offset_2;
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typedef typename Exact_offset_2::Offset_polygon_2 Offset_polygon_2;
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Base base;
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Exact_offset_2 exact_offset (base);
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Offset_polygon_2 offset_bound;
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std::list<Offset_polygon_2> offset_holes;
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exact_offset (pwh, r,
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offset_bound, std::back_inserter(offset_holes));
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return (typename Gps_traits_2<ConicTraits>::Polygon_with_holes_2
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(offset_bound, offset_holes.begin(), offset_holes.end()));
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}
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/*!
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* Compute the offset of a given simple polygon by a given radius,
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* by decomposing it to convex sub-polygons and computing the union of their
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* offsets.
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* Note that as the input polygon may not be convex, its offset may not be
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* simply connected. The result is therefore represented as a polygon with
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* holes.
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* \param pgn The polygon.
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* \param r The offset radius.
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* \param decomp A functor for decomposing polygons.
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* \return The offset polygon.
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*/
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template <class ConicTraits, class Container, class DecompositionStrategy>
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typename Gps_traits_2<ConicTraits>::Polygon_with_holes_2
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offset_polygon_2 (const Polygon_2<typename ConicTraits::Rat_kernel,
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Container>& pgn,
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const typename ConicTraits::Rat_kernel::FT& r,
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const DecompositionStrategy&,
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const ConicTraits& )
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{
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typedef Exact_offset_base_2<ConicTraits, Container> Base;
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typedef Offset_by_decomposition_2<Base, DecompositionStrategy>
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Exact_offset_2;
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typedef typename Exact_offset_2::Offset_polygon_2 Offset_polygon_2;
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Base base;
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Exact_offset_2 exact_offset (base);
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Offset_polygon_2 offset_bound;
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std::list<Offset_polygon_2> offset_holes;
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exact_offset (pgn, r,
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offset_bound, std::back_inserter(offset_holes));
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return (typename Gps_traits_2<ConicTraits>::Polygon_with_holes_2
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(offset_bound, offset_holes.begin(), offset_holes.end()));
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}
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/*!
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* Compute the inset of a given simple polygon by a given radius, using the
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* convolution method.
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* Note that as the input polygon may not be convex, its inset may not be
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* simply connected. The result is therefore represented as a set of polygons.
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* \param pgn The polygon.
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* \param r The inset radius.
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* \param oi An output iterator for the inset polygons.
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* Its value-type must be Gps_traits_2<ConicTraits>::Polygon_2.
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* \return A past-the-end iterator for the inset polygons.
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*/
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template <class ConicTraits, class Container, class OutputIterator>
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OutputIterator
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inset_polygon_2 (const Polygon_2<typename ConicTraits::Rat_kernel,
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Container>& pgn,
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const typename ConicTraits::Rat_kernel::FT& r,
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const ConicTraits& ,
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OutputIterator oi)
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{
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typedef Exact_offset_base_2<ConicTraits, Container> Base;
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typedef Offset_by_convolution_2<Base> Exact_offset_2;
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Base base;
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Exact_offset_2 exact_offset (base);
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oi = exact_offset.inset (pgn, r,
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oi);
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return (oi);
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}
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} //namespace CGAL
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#endif
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