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// Copyright (c) 2006-2008 Fernando Luis Cacciola Carballal. All rights reserved.
//
// This file is part of CGAL (www.cgal.org).
//
// $URL: https://github.com/CGAL/cgal/blob/v6.1.1/Straight_skeleton_2/include/CGAL/create_offset_polygons_2.h $
// $Id: include/CGAL/create_offset_polygons_2.h 08b27d3db14 $
// SPDX-License-Identifier: GPL-3.0-or-later OR LicenseRef-Commercial
//
// Author(s) : Fernando Cacciola <fernando_cacciola@ciudad.com.ar>
//
#ifndef CGAL_CREATE_OFFSET_POLYGONS_2_H
#define CGAL_CREATE_OFFSET_POLYGONS_2_H
#include <CGAL/license/Straight_skeleton_2.h>
#include <CGAL/Straight_skeleton_2/Straight_skeleton_aux.h>
#include <CGAL/create_straight_skeleton_2.h>
#include <CGAL/compute_outer_frame_margin.h>
#include <CGAL/Polygon_offset_builder_2.h>
#include <CGAL/Straight_skeleton_converter_2.h>
#include <CGAL/Straight_skeleton_builder_2.h>
#include <CGAL/Straight_skeleton_2/Polygon_iterators.h>
#include <CGAL/assertions.h>
#include <CGAL/Cartesian_converter.h>
#include <CGAL/Default.h>
#include <CGAL/Kernel_traits.h>
#include <CGAL/tags.h>
#include <optional>
#include <boost/range/value_type.hpp>
#include <memory>
#include <algorithm>
#include <iostream>
#include <iterator>
#include <type_traits>
#include <vector>
namespace CGAL {
namespace CGAL_SS_i {
template<class FT, class PointIterator, class HoleIterator, class K>
std::shared_ptr< Straight_skeleton_2<K> >
create_partial_interior_straight_skeleton_2 ( FT const& aMaxTime
, PointIterator aOuterContour_VerticesBegin
, PointIterator aOuterContour_VerticesEnd
, HoleIterator aHolesBegin
, HoleIterator aHolesEnd
, K const& // aka 'SK'
)
{
CGAL_precondition( aMaxTime > static_cast<FT>(0) ) ;
typedef Straight_skeleton_2<K> Ss ;
typedef Straight_skeleton_builder_traits_2<K> SsBuilderTraits;
typedef Straight_skeleton_builder_2<SsBuilderTraits,Ss> SsBuilder;
typedef typename K::FT KFT ;
typedef typename std::iterator_traits<PointIterator>::value_type InputPoint ;
typedef typename Kernel_traits<InputPoint>::Kernel InputKernel ;
Cartesian_converter<InputKernel, K> conv ;
typename InputKernel::FT lMaxTime = aMaxTime;
std::optional<KFT> lOptMaxTime(conv(lMaxTime)) ;
SsBuilder ssb( lOptMaxTime ) ;
ssb.enter_contour( aOuterContour_VerticesBegin, aOuterContour_VerticesEnd, conv ) ;
for ( HoleIterator hi = aHolesBegin ; hi != aHolesEnd ; ++ hi )
ssb.enter_contour( CGAL_SS_i::vertices_begin(*hi), CGAL_SS_i::vertices_end(*hi), conv ) ;
return ssb.construct_skeleton();
}
template<class FT, class PointIterator, class K>
std::shared_ptr< Straight_skeleton_2<K> >
create_partial_exterior_straight_skeleton_2 ( FT const& aMaxOffset
, PointIterator aVerticesBegin
, PointIterator aVerticesEnd
, K const& k // aka 'SK'
)
{
CGAL_precondition( aMaxOffset > 0 ) ;
typedef typename std::iterator_traits<PointIterator>::value_type Point_2;
typedef typename Kernel_traits<Point_2>::Kernel IK;
typedef typename IK::FT IFT;
std::shared_ptr<Straight_skeleton_2<K> > rSkeleton;
// That's because we might not have FT == IK::FT (e.g. `double` and `Core`)
// Note that we can also have IK != K (e.g. `Simple_cartesian<Core>` and `EPICK`)
IFT lOffset = aMaxOffset;
// @todo This likely should be done in the kernel K rather than the input kernel (i.e. the same
// converter stuff that is done in `create_partial_exterior_straight_skeleton_2`?).
std::optional<IFT> margin = compute_outer_frame_margin(aVerticesBegin,
aVerticesEnd,
lOffset);
if ( margin )
{
const IFT lm = *margin;
const Bbox_2 bbox = bbox_2(aVerticesBegin, aVerticesEnd);
const IFT fxmin = IFT(bbox.xmin()) - lm ;
const IFT fxmax = IFT(bbox.xmax()) + lm ;
const IFT fymin = IFT(bbox.ymin()) - lm ;
const IFT fymax = IFT(bbox.ymax()) + lm ;
Point_2 frame[4] ;
frame[0] = Point_2(fxmin,fymin) ;
frame[1] = Point_2(fxmax,fymin) ;
frame[2] = Point_2(fxmax,fymax) ;
frame[3] = Point_2(fxmin,fymax) ;
typedef std::vector<Point_2> Hole ;
Hole lPoly(aVerticesBegin, aVerticesEnd);
std::reverse(lPoly.begin(), lPoly.end());
std::vector<Hole> holes ;
holes.push_back(lPoly) ;
rSkeleton = create_partial_interior_straight_skeleton_2(aMaxOffset, frame, frame+4, holes.begin(), holes.end(), k ) ;
}
return rSkeleton ;
}
//
// Kernel != Skeleton::kernel. The skeleton is converted to Straight_skeleton_2<Kernel>
//
template<class OutPolygon, class FT, class Skeleton, class K>
std::vector< std::shared_ptr<OutPolygon> >
create_offset_polygons_2 ( FT const& aOffset, Skeleton const& aSs, K const& , Tag_false )
{
static_assert(!(std::is_same<OutPolygon, CGAL::Default>::value));
typedef std::shared_ptr<OutPolygon> OutPolygonPtr ;
typedef std::vector<OutPolygonPtr> OutPolygonPtrVector ;
typedef Straight_skeleton_2<K> OfSkeleton ;
typedef Polygon_offset_builder_traits_2<K> OffsetBuilderTraits;
typedef Polygon_offset_builder_2<OfSkeleton,OffsetBuilderTraits,OutPolygon> OffsetBuilder;
OutPolygonPtrVector rR ;
std::shared_ptr<OfSkeleton> lConvertedSs = convert_straight_skeleton_2<OfSkeleton>(aSs);
OffsetBuilder ob( *lConvertedSs );
ob.construct_offset_contours(aOffset, std::back_inserter(rR) ) ;
return rR ;
}
//
// Kernel == Skeleton::kernel, no conversion
//
template<class OutPolygon, class FT, class Skeleton, class K>
std::vector< std::shared_ptr<OutPolygon> >
create_offset_polygons_2 ( FT const& aOffset, Skeleton const& aSs, K const& /*k*/, Tag_true )
{
static_assert(!(std::is_same<OutPolygon, CGAL::Default>::value));
typedef std::shared_ptr<OutPolygon> OutPolygonPtr ;
typedef std::vector<OutPolygonPtr> OutPolygonPtrVector ;
typedef Polygon_offset_builder_traits_2<K> OffsetBuilderTraits;
typedef Polygon_offset_builder_2<Skeleton,OffsetBuilderTraits,OutPolygon> OffsetBuilder;
OffsetBuilder ob(aSs);
typename K::FT lOffset = aOffset;
OutPolygonPtrVector rR ;
ob.construct_offset_contours(lOffset, std::back_inserter(rR) ) ;
return rR ;
}
// Allow failure due to invalid straight skeletons to go through the users
template<class Skeleton>
Skeleton const& dereference ( std::shared_ptr<Skeleton> const& ss )
{
CGAL_precondition(ss.get() != 0);
return *ss;
}
} // namespace CGAL_SS_i
template<class OutPolygon, class FT, class Skeleton,
class K = Exact_predicates_inexact_constructions_kernel>
std::vector<std::shared_ptr<OutPolygon> >
inline
create_offset_polygons_2(const FT& aOffset,
const Skeleton& aSs,
const K& k = K())
{
typename CGAL_SS_i::Is_same_type<K, typename Skeleton::Traits>::type same_kernel;
return CGAL_SS_i::create_offset_polygons_2<OutPolygon>(aOffset, aSs, k, same_kernel);
}
////////////////////////////////////////////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////////////////////////////////////////////
/// INTERIOR
template <class OutPolygon_ = CGAL::Default,
class FT, class APolygon, class HoleIterator,
class OfK = Exact_predicates_inexact_constructions_kernel,
class SsK = Exact_predicates_inexact_constructions_kernel>
std::vector<std::shared_ptr<CGAL_SS_i::Polygon_return_type<OutPolygon_, APolygon, OfK> > >
inline
create_interior_skeleton_and_offset_polygons_2(const FT& aOffset,
const APolygon& aOuterBoundary,
HoleIterator aHolesBegin,
HoleIterator aHolesEnd,
const OfK& ofk = OfK(),
const SsK& ssk = SsK(),
std::enable_if_t<CGAL::is_iterator<HoleIterator>::value>* = 0)
{
using OutPolygon = CGAL_SS_i::Polygon_return_type<OutPolygon_, APolygon, OfK>;
return create_offset_polygons_2<OutPolygon>(
aOffset,
CGAL_SS_i::dereference(
CGAL_SS_i::create_partial_interior_straight_skeleton_2(
aOffset,
CGAL_SS_i::vertices_begin(aOuterBoundary),
CGAL_SS_i::vertices_end (aOuterBoundary),
aHolesBegin,
aHolesEnd,
ssk)),
ofk);
}
// Overload where APolygon is a simple polygon (no holes)
template <class OutPolygon_ = CGAL::Default,
class FT, class APolygon,
class OfK = Exact_predicates_inexact_constructions_kernel,
class SsK = Exact_predicates_inexact_constructions_kernel>
std::vector<std::shared_ptr<CGAL_SS_i::Polygon_return_type<OutPolygon_, APolygon, OfK> > >
inline
create_interior_skeleton_and_offset_polygons_2(const FT& aOffset,
const APolygon& aPoly,
const OfK& ofk = OfK(),
const SsK& ssk = SsK(),
std::enable_if_t<
! CGAL_SS_i::has_Hole_const_iterator<APolygon>::value>* = nullptr)
{
using OutPolygon = CGAL_SS_i::Polygon_return_type<OutPolygon_, APolygon, OfK>;
std::vector<APolygon> no_holes;
return create_interior_skeleton_and_offset_polygons_2<OutPolygon>(aOffset, aPoly,
no_holes.begin(), no_holes.end(),
ofk, ssk);
}
////////////////////////////////////////////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////////////////////////////////////////////
/// EXTERIOR
/*! create_exterior_skeleton_and_offset_polygons_2 (no sorting of the result) */
// Overload where Polygon actually is a simple polygon (no holes)
template <class OutPolygon_ = CGAL::Default,
class FT, class APolygon,
class OfK = Exact_predicates_inexact_constructions_kernel,
class SsK = Exact_predicates_inexact_constructions_kernel>
std::vector<std::shared_ptr<CGAL_SS_i::Polygon_return_type<OutPolygon_, APolygon, OfK> > >
inline
create_exterior_skeleton_and_offset_polygons_2(const FT& aOffset,
const APolygon& aPoly,
const OfK& ofk = OfK(),
const SsK& ssk = SsK(),
std::enable_if_t<
! CGAL_SS_i::has_Hole_const_iterator<APolygon>::value>* = nullptr)
{
using OutPolygon = CGAL_SS_i::Polygon_return_type<OutPolygon_, APolygon, OfK>;
return create_offset_polygons_2<OutPolygon>(
aOffset,
CGAL_SS_i::dereference(
CGAL_SS_i::create_partial_exterior_straight_skeleton_2(
aOffset,
CGAL_SS_i::vertices_begin(aPoly),
CGAL_SS_i::vertices_end (aPoly),
ssk)),
ofk);
}
} // namespace CGAL
#endif // CGAL_CREATE_OFFSET_POLYGONS_2_H
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