118 lines
3.7 KiB
C
118 lines
3.7 KiB
C
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// Copyright (c) 2006-2008 Fernando Luis Cacciola Carballal. 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/Straight_skeleton_2/include/CGAL/compute_outer_frame_margin.h $
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// $Id: compute_outer_frame_margin.h 0779373 2020-03-26T13:31:46+01:00 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) : Fernando Cacciola <fernando_cacciola@ciudad.com.ar>
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//
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#ifndef CGAL_COMPUTE_OUTER_FRAME_MARGIN_H
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#define CGAL_COMPUTE_OUTER_FRAME_MARGIN_H
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#include <CGAL/license/Straight_skeleton_2.h>
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#include <vector>
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#include <algorithm>
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#include <boost/shared_ptr.hpp>
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#include <boost/optional/optional.hpp>
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#include <CGAL/algorithm.h>
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#include <CGAL/Polygon_offset_builder_traits_2.h>
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namespace CGAL {
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template<class ForwardPointIterator, class Traits>
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boost::optional< typename Traits::FT > compute_outer_frame_margin ( ForwardPointIterator aBegin
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, ForwardPointIterator aEnd
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, typename Traits::FT aOffset
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, Traits const& aTraits
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)
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{
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typedef typename Traits::Kernel Kernel ;
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typedef typename Traits::FT FT ;
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typedef typename Traits::Point_2 Point_2 ;
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typedef typename Traits::Segment_2 Segment_2 ;
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typedef typename Traits::Trisegment_2_ptr Trisegment_2_ptr ;
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Kernel kernel ;
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typename Kernel::Equal_2 equal = kernel.equal_2_object();
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typename Kernel::Collinear_2 collinear = kernel.collinear_2_object();
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typename Kernel::Compute_squared_distance_2 squared_distance = kernel.compute_squared_distance_2_object();
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typename Kernel::Construct_segment_2 construct_segment = kernel.construct_segment_2_object();
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typedef boost::optional<Point_2> OptionalPoint_2 ;
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FT lMaxSDist(0.0) ;
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ForwardPointIterator lLast = std::prev(aEnd) ;
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bool lOverflow = false ;
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for ( ForwardPointIterator lCurr = aBegin ; lCurr != aEnd ; ++ lCurr )
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{
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ForwardPointIterator lPrev = ( lCurr == aBegin ? lLast : std::prev (lCurr) ) ;
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ForwardPointIterator lNext = ( lCurr == lLast ? aBegin : std::next (lCurr) ) ;
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if ( !equal(*lPrev,*lCurr) && !equal(*lCurr,*lNext) && !collinear(*lPrev,*lCurr,*lNext) )
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{
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Segment_2 lLEdge = construct_segment(*lPrev,*lCurr);
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Segment_2 lREdge = construct_segment(*lCurr,*lNext);
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OptionalPoint_2 lP = Construct_offset_point_2(aTraits)(aOffset,lLEdge,lREdge, Trisegment_2_ptr() );
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if ( !lP )
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{
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lOverflow = true ;
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break ;
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}
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FT lSDist = squared_distance(*lCurr,*lP);
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if ( ! CGAL_NTS is_valid ( lSDist )
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|| ! CGAL_NTS is_finite( lSDist )
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)
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{
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lOverflow = true ;
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break ;
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}
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if ( lSDist > lMaxSDist )
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lMaxSDist = lSDist ;
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}
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}
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if ( ! lOverflow )
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{
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FT lDist = CGAL_SS_i::inexact_sqrt(lMaxSDist) ;
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return boost::optional<FT>( lDist + ( aOffset * FT(1.05) ) ) ; // Add a %5 gap
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}
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else
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return boost::optional<FT>();
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}
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template<class ForwardPointIterator, class FT>
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boost::optional<FT> compute_outer_frame_margin ( ForwardPointIterator aBegin, ForwardPointIterator aEnd, FT aOffset )
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{
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typedef typename std::iterator_traits<ForwardPointIterator>::value_type Point_2 ;
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typedef typename Kernel_traits<Point_2>::Kernel K;
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Polygon_offset_builder_traits_2<K> traits ;
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return compute_outer_frame_margin(aBegin,aEnd,aOffset,traits);
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}
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} // end namespace CGAL
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#endif // CGAL_COMPUTE_OUTER_FRAME_MARGIN_H //
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// EOF //
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