cgal/Straight_skeleton_2/include/CGAL/Polygon_offset_builder_2.h

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// Copyright (c) 2005, 2006 Fernando Luis Cacciola Carballal. 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) : Fernando Cacciola <fernando_cacciola@ciudad.com.ar>
//
#ifndef CGAL_POLYGON_OFFSET_BUILDER_2_H
#define CGAL_POLYGON_OFFSET_BUILDER_2_H 1
#include <vector>
#include <algorithm>
#include <boost/shared_ptr.hpp>
#include <boost/optional/optional.hpp>
#include <CGAL/Straight_skeleton_2/Straight_skeleton_aux.h>
#include <CGAL/Polygon_offset_builder_traits_2.h>
CGAL_BEGIN_NAMESPACE
template<class Ss_, class Traits_, class Container_>
class Polygon_offset_builder_2
{
public :
typedef Ss_ Ss ;
typedef Traits_ Traits ;
typedef Container_ Container ;
typedef typename Traits::Kernel K ;
typedef typename Traits::FT FT ;
typedef typename Traits::Point_2 Point_2 ;
typedef boost::shared_ptr<Container> ContainerPtr ;
Polygon_offset_builder_2( Ss const& aSs, Traits const& aTraits = Traits() ) ;
template<class OutputIterator>
OutputIterator construct_offset_contours( FT aTime, OutputIterator aOut ) ;
private:
typedef typename Ss::Halfedge_const_handle Halfedge_const_handle ;
typedef typename Ss::Vertex_const_handle Vertex_const_handle ;
typedef std::vector<Halfedge_const_handle> Halfedge_vector ;
typedef typename Traits::Segment_2 Segment_2 ;
typedef typename Traits::Trisegment_2 Trisegment_2 ;
typedef typename Traits::Seeded_trisegment_2 Seeded_trisegment_2 ;
typedef CGAL_SS_i::Triedge<Halfedge_const_handle> Triedge ;
bool handled_assigned( Halfedge_const_handle aH ) const
{
const Halfedge_const_handle cNull ;
return aH != cNull ;
}
Halfedge_const_handle LocateHook( FT aTime, Halfedge_const_handle aBisector ) ;
void AddOffsetVertex( FT aTime, Halfedge_const_handle aHook, ContainerPtr aPoly ) ;
template<class OutputIterator>
OutputIterator TraceOffsetPolygon( FT aTime, Halfedge_const_handle aHook, OutputIterator aOut ) ;
Halfedge_const_handle LocateSeed( FT aTime ) ;
bool IsVisited( Halfedge_const_handle aBisector ) { return mVisitedBisectors[aBisector->id()] != 0 ; }
void Visit( Halfedge_const_handle aBisector ) { mVisitedBisectors[aBisector->id()] = 1 ; }
inline Segment_2 CreateSegment ( Halfedge_const_handle aH ) const
{
Point_2 s = aH->opposite()->vertex()->point() ;
Point_2 t = aH->vertex()->point() ;
return K().construct_segment_2_object()(s,t);
}
Triedge GetTriedge( Vertex_const_handle aSeed ) const
{
typedef typename Ss::Vertex Vertex ;
typedef typename Vertex::Defining_contour_halfedges_const_circulator circ ;
circ cb = aSeed->defining_contour_halfedges_begin() ;
circ c = cb ;
Halfedge_const_handle lE[3] ;
int d = 0 ;
do
{
lE[d++] = *c++;
}
while( d < 3 && c != cb ) ;
Triedge rTriedge(lE[0],lE[1],lE[2]);
CGAL_POLYOFFSET_TRACE(3,"Triedge for " << v2str(*aSeed) << ": (E" << lE[0]->id() << ", E" << lE[1]->id() << ", E" << lE[2]->id() << ")" ) ;
CGAL_postcondition(rTriedge.is_valid());
return rTriedge ;
}
Trisegment_2 CreateTrisegment ( Halfedge_const_handle aE0
, Halfedge_const_handle aE1
, Halfedge_const_handle aE2
) const
{
return *Construct_ss_trisegment_2(mTraits)(CreateSegment(aE0),CreateSegment(aE1),CreateSegment(aE2));
}
Trisegment_2 CreateTrisegment ( Triedge const& aTriedge ) const
{
return *Construct_ss_trisegment_2(mTraits)(CreateSegment(aTriedge.e0()),CreateSegment(aTriedge.e1()),CreateSegment(aTriedge.e2()));
}
Trisegment_2 CreateTrisegment ( Vertex_const_handle aSeed ) const
{
return aSeed->is_skeleton() ? CreateTrisegment(GetTriedge(aSeed)) : Trisegment_2::null() ;
}
Seeded_trisegment_2 CreateSeededTrisegment ( Halfedge_const_handle aE0
, Halfedge_const_handle aE1
, Halfedge_const_handle aE2
, Vertex_const_handle aLSeed
, Vertex_const_handle aRSeed
) const
{
return Construct_ss_seeded_trisegment_2(mTraits)(CreateTrisegment(aE0,aE1,aE2)
,CreateTrisegment(aLSeed)
,CreateTrisegment(aRSeed)
);
}
Seeded_trisegment_2 CreateSeededTrisegment ( Vertex_const_handle aNode
, Vertex_const_handle aLSeed
, Vertex_const_handle aRSeed
) const
{
return Construct_ss_seeded_trisegment_2(mTraits)(CreateTrisegment(aNode)
,CreateTrisegment(aLSeed)
,CreateTrisegment(aRSeed)
);
}
Comparison_result Compare_offset_against_event_time( FT aT, Halfedge_const_handle aBisector, Halfedge_const_handle aNextBisector ) const
{
CGAL_assertion(aBisector->is_bisector());
CGAL_assertion(handle_assigned(aBisector->opposite()));
CGAL_assertion(aBisector->opposite()->is_bisector());
CGAL_assertion(aNextBisector->is_bisector());
CGAL_assertion(handle_assigned(aNextBisector->opposite()));
CGAL_assertion(aNextBisector->opposite()->is_bisector());
Halfedge_const_handle lBorderA = aBisector->defining_contour_edge();
Halfedge_const_handle lBorderB = aBisector->opposite()->defining_contour_edge();
Halfedge_const_handle lBorderC = aNextBisector->opposite()->defining_contour_edge();
Vertex_const_handle lLSeed = aBisector->opposite()->vertex();
Vertex_const_handle lRSeed = aBisector->vertex();
CGAL_POLYOFFSET_TRACE(3,"Comparing offset " << aT << " against event [(E" << lBorderA->id() << ",E" << lBorderB->id() << ",E" << lBorderC->id() << ")(LS=" << v2str(*lLSeed) << ",RS=" << v2str(*lRSeed) << ")]");
return Compare_offset_against_event_time_2(mTraits)(aT,CreateSeededTrisegment(lBorderA,lBorderB,lBorderC,lLSeed,lRSeed));
}
boost::optional<Point_2> Construct_offset_point( FT aT, Halfedge_const_handle aBisector ) const
{
CGAL_assertion(aBisector->is_bisector());
CGAL_assertion(handle_assigned(aBisector->opposite()));
CGAL_assertion(aBisector->opposite()->is_bisector());
Halfedge_const_handle lBorderA = aBisector->defining_contour_edge();
Halfedge_const_handle lBorderB = aBisector->opposite()->defining_contour_edge();
// If aBisector is not a border bisector the offset point construction needs to get to the event
// that generated the node closer to the border. That event is lSrcEvent
// (relevant only for inner bisectors)
Seeded_trisegment_2 lSrcEvent ;
if ( aBisector->is_inner_bisector() )
{
// aBisector might be pointing toward or away from the border, so we need to determine which
// one of its endpoint nodes is closer to the border, that is, which one has the smaller event time.
Seeded_trisegment_2 lSrcEventS, lSrcEventT ;
Vertex_const_handle lNodeS = aBisector->opposite()->vertex();
Vertex_const_handle lNodeT = aBisector->vertex();
CGAL_assertion ( lNodeS->is_skeleton() ) ;
CGAL_assertion ( lNodeT->is_skeleton() ) ;
Vertex_const_handle lLSeedS = aBisector->prev()->opposite()->vertex();
Vertex_const_handle lRSeedS = aBisector->opposite()->next()->vertex();
lSrcEventS = CreateSeededTrisegment(lNodeS,lLSeedS,lRSeedS);
Vertex_const_handle lLSeedT = aBisector->opposite()->prev()->opposite()->vertex();
Vertex_const_handle lRSeedT = aBisector->next()->vertex();
lSrcEventT = CreateSeededTrisegment(lNodeT,lLSeedT,lRSeedT);
lSrcEvent = Compare_ss_event_times_2(mTraits)(lSrcEventS,lSrcEventT) != LARGER ? lSrcEventS : lSrcEventT ;
}
return Construct_offset_point_2(mTraits)(aT
,CreateSegment(lBorderA)
,CreateSegment(lBorderB)
,lSrcEvent
);
}
void ResetVisitedBisectorsMap();
Traits const& mTraits ;
std::vector<int> mVisitedBisectors;
Halfedge_vector mBorders ;
};
CGAL_END_NAMESPACE
#include <CGAL/Straight_skeleton_2/Polygon_offset_builder_2_impl.h>
#endif // CGAL_POLYGON_OFFSET_BUILDER_2_H //
// EOF //