[u/mrichter/AliRoot.git] / MUON / AliMUONContourMaker.cxx

/**************************************************************************
* Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. *
*                                                                        *
* Author: The ALICE Off-line Project.                                    *
* Contributors are mentioned in the code where appropriate.              *
*                                                                        *
* Permission to use, copy, modify and distribute this software and its   *
* documentation strictly for non-commercial purposes is hereby granted   *
* without fee, provided that the above copyright notice appears in all   *
* copies and that both the copyright notice and this permission notice   *
* appear in the supporting documentation. The authors make no claims     *
* about the suitability of this software for any purpose. It is          *
* provided "as is" without express or implied warranty.                  *
**************************************************************************/

// $Id$

///
/// Maker/merger of contours. Can create contour from a set polygons or
/// merger a set of contours into a single one.
/// 
/// This is based on (one of the) algorithm found in 
/// Diane L. Souvaine and Iliana Bjorling-Sachs,
/// Proceedings of the IEEE, Vol. 80, No. 9, September 1992, p. 1449
///
/// Note that besides the AliMUON prefix, nothing is really MUON specific
/// in this class...
///
/// \author Laurent Aphecetche, Subatech
///

#include "AliMUONContourMaker.h"

#include "AliCodeTimer.h"
#include "AliLog.h"
#include "AliMUONContour.h"
#include "AliMUONPointWithRef.h"
#include "AliMUONPolygon.h"
#include "AliMUONSegment.h"
#include "AliMUONSegmentTree.h"
#include "Riostream.h"
#include "TArrayD.h"
#include "TMath.h"
#include <cassert>

/// \cond CLASSIMP
ClassImp(AliMUONContourMaker)
/// \endcond

namespace
{
  void PrintSegments(const TObjArray& array)
  {
    TIter next(&array);
    AliMUONSegment* s;
    Int_t i(0);
    while ( ( s = static_cast<AliMUONSegment*>(next()) ) )
    {
      cout << Form("i=%d %s",i,s->AsString()) << endl;
      ++i;
    }
  }
}

//_____________________________________________________________________________
AliMUONContourMaker::AliMUONContourMaker() 
{
}

//_____________________________________________________________________________
AliMUONContourMaker::~AliMUONContourMaker()
{
}

//_____________________________________________________________________________
AliMUONContour* 
AliMUONContourMaker::CreateContour(const TObjArray& polygons, const char* name) const
{
  /// Create the contour of the polygon array
  /// and get back the intermediate verticals and horizontal segments
  /// both arrays are arrays of AliMUONSegment objects.
  
  AliCodeTimerAuto("");
  
  if ( polygons.IsEmpty() ) return 0x0; // protection against user error...
  
  // Sanity check : insure that all polygons are oriented counter-clockwise
  TIter next(&polygons);
  AliMUONPolygon* pol;
  while ( ( pol = static_cast<AliMUONPolygon*>(next()) ) )
  {
    if ( !pol->IsCounterClockwiseOriented() )
    {
      AliError(Form("Got a clockwise oriented polygon in CreateContour(%s). That's not OK !",name));
      StdoutToAliError(polygons.Print());
      return 0x0;
    }
  }
  
  AliMUONContour* contour(0x0);
  
  if ( polygons.GetLast() == 0 ) 
  {
    AliCodeTimerAuto("Trivial case");
    contour = new AliMUONContour(name);
    pol = static_cast<const AliMUONPolygon*>(polygons.First());
    contour->Add(*pol);
    contour->AssertOrientation();
    return contour;
  }
  
  TObjArray polygonVerticalEdges; // arrray of AliMUONSegment objects  
  polygonVerticalEdges.SetOwner(kTRUE);
  // get vertical edges of input polygons
  GetVerticalEdges(polygons,polygonVerticalEdges);
  
  // sort them in ascending x order
  // if same x, insure that left edges are before right edges
  // within same x, order by increasing bottommost y (see AliMUONSegment::Compare method)
  polygonVerticalEdges.Sort();
  
  if ( polygonVerticalEdges.GetLast()+1 < 2 ) 
  {
    AliError(Form("Got too few edges here for createContour %s",name));
    polygons.Print();
    TObject* o(0x0);
    o->Print();
  }
  
  // Find the vertical edges of the merged contour. This is the meat of the algorithm...
  TObjArray contourVerticalEdges;
  contourVerticalEdges.SetOwner(kTRUE);
  Sweep(polygonVerticalEdges,contourVerticalEdges);
  
  TObjArray horizontals;
  horizontals.SetOwner(kTRUE);
  VerticalToHorizontal(contourVerticalEdges,horizontals);
  
  contour = FinalizeContour(contourVerticalEdges,horizontals);
  
  if ( contour && name ) contour->SetName(name);
  
  return contour;
}

//_____________________________________________________________________________
AliMUONContour* 
AliMUONContourMaker::FinalizeContour(const TObjArray& verticals,
                                     const TObjArray& horizontals) const
{  
  /// For a list of vertical and horizontal edges, we build the final
  /// contour object.
  
  AliCodeTimerAuto("");
  
  TObjArray all; // array of AliMUONSegment
  TObjArray inorder; // array of AliMUONSegment

  all.SetOwner(kFALSE);
  inorder.SetOwner(kFALSE);
    
  for ( Int_t i = 0; i <= verticals.GetLast(); ++i ) 
  {
    all.Add(verticals.UncheckedAt(i));
    all.Add(horizontals.UncheckedAt(i));
  }
  
  Int_t i(0);
  
  AliMUONContour* contour = new AliMUONContour;
  
  int total(0);
  
  while ( !all.IsEmpty() )
  {
    total++;
    
    if ( total > 1000 ) 
    {
      AliError("Total 1000 reached !!!!");
      return 0x0;
    }
    
    AliMUONSegment* si = static_cast<AliMUONSegment*>(all.UncheckedAt(i));
    inorder.Add(si);
    const AliMUONSegment* all0 = static_cast<const AliMUONSegment*>(all.First());
    if ( i != 0 && AliMUONSegment::AreEqual(si->EndX(),all0->StartX()) && AliMUONSegment::AreEqual(si->EndY(),all0->StartY()) )
    {
      Int_t n(-1);
      
      AliMUONPolygon polygon(inorder.GetLast()+2);

      // we got a cycle. Add it to the contour
      for ( Int_t j = 0; j <= inorder.GetLast(); ++j ) 
      {
        AliMUONSegment* s = static_cast<AliMUONSegment*>(inorder.UncheckedAt(j));
        polygon.SetVertex(++n,s->StartX(),s->StartY());
        all.Remove(s);
      }
      
      all.Compress();

      polygon.Close();
      
      contour->Add(polygon);
      
      if ( ! all.IsEmpty() )
      {
        i = 0;
        inorder.Clear();
      }
      continue;
    }
    
    for ( Int_t j = 0; j <= all.GetLast(); ++j) 
    {
      if ( j != i ) 
      {        
        const AliMUONSegment* sj = static_cast<const AliMUONSegment*>(all.UncheckedAt(j));
        if ( AliMUONSegment::AreEqual(si->EndX(),sj->StartX()) && AliMUONSegment::AreEqual(si->EndY(),sj->StartY()))
        {
          i = j;
          break;
        }
      }
    }    
  }
  
  contour->AssertOrientation(kTRUE);
  return contour;
}


//_____________________________________________________________________________
void 
AliMUONContourMaker::GetVerticalEdges(const TObjArray& polygons, TObjArray& polygonVerticalEdges) const
{
  /// From an array of polygons, extract the list of vertical edges.
  /// Output array polygonVerticalEdges should be empty before calling.
  
  AliCodeTimerAuto("");
  
  for ( Int_t i = 0; i <= polygons.GetLast(); ++i ) 
  {
    const AliMUONPolygon* g = static_cast<const AliMUONPolygon*>(polygons.UncheckedAt(i));
    for ( Int_t j = 0; j < g->NumberOfVertices()-1; ++j ) 
    {
      if ( AliMUONSegment::AreEqual(g->X(j),g->X(j+1)) ) // segment is vertical
      {
        polygonVerticalEdges.Add(new AliMUONSegment(g->X(j),g->Y(j),g->X(j+1),g->Y(j+1)));
      }
    }
  }
}


//_____________________________________________________________________________
void
AliMUONContourMaker::GetYPositions(const TObjArray& polygonVerticalEdges,
                                   TArrayD& yPositions) const
{
  /// Fill the array yPositions with the different y positions found in 
  /// polygonVerticalEdges
  
  AliCodeTimerAuto("");
  
  Double_t* y = new Double_t[polygonVerticalEdges.GetSize()*2];
  Int_t n(0);
  
  for ( Int_t i = 0; i < polygonVerticalEdges.GetLast(); ++i ) 
  {
    AliMUONSegment* s = static_cast<AliMUONSegment*>(polygonVerticalEdges.UncheckedAt(i));
    y[n] = s->StartY();
    y[n+1] = s->EndY();
    n += 2;
  }
  Int_t* ix = new Int_t[n+1];
  
  TMath::Sort(n,y,ix,kFALSE);
  
  yPositions.Set(n+1);
  
  Int_t u(0);
  Double_t x(FLT_MAX);
  
  for ( Int_t i = 0; i < n; ++i ) 
  {
    if ( y[ix[i]] != x )
    {
      yPositions[u] = y[ix[i]];
      x = y[ix[i]];
      ++u;
    }
  }

  yPositions.Set(u);
  
  delete[] ix;
  delete[] y;
  
}

//_____________________________________________________________________________
AliMUONContour* 
AliMUONContourMaker::MergeContour(const TObjArray& contours, const char* name) const
{
  /// Merge all the polygons of all contours into a single contour
  
  AliCodeTimerAuto("");
  
  TObjArray polygons;
  polygons.SetOwner(kTRUE);
  
  TIter next(&contours);
  AliMUONContour* contour;
  while ( ( contour = static_cast<AliMUONContour*>(next()) ) )
  {
    const TObjArray* contourPolygons = contour->Polygons();
    TIter nextPol(contourPolygons);
    AliMUONPolygon* pol;
    while ( ( pol = static_cast<AliMUONPolygon*>(nextPol()) ) )
    {
      polygons.Add(new AliMUONPolygon(*pol));
    }
  }
  
  if ( polygons.IsEmpty() ) return 0x0;
  
  contour = CreateContour(polygons,name);
  
  return contour;
}

//_____________________________________________________________________________
void 
AliMUONContourMaker::SortPoints(const TObjArray& polygonVerticalEdges, 
                                TObjArray& sortedPoints) const
{
  /// Sort the point of the vertical edges in ascending order, first on ordinate, 
  /// then on abcissa, and put them in output vector sortedPoints.
  /// Output array sortedPoints should be empty before calling this method.
  
  AliCodeTimerAuto("");
  
  for ( Int_t i = 0; i <= polygonVerticalEdges.GetLast(); ++i )
  {
    const AliMUONSegment* e = static_cast<const AliMUONSegment*>(polygonVerticalEdges.UncheckedAt(i));
    sortedPoints.Add(new AliMUONPointWithRef(e->StartX(),e->StartY(),i));
    sortedPoints.Add(new AliMUONPointWithRef(e->EndX(),e->EndY(),i));
    // note that we keep track of the original edge, which is used
    // later on to deduce orientation of horizontal edges.
  }
  
  sortedPoints.Sort(); 
}

//_____________________________________________________________________________
void 
AliMUONContourMaker::Sweep(const TObjArray& polygonVerticalEdges, 
                           TObjArray& contourVerticalEdges) const
{
  /// This is the meat of the algorithm of the contour merging...
  
  AliCodeTimerAuto("");
  
  TArrayD yPositions;
  GetYPositions(polygonVerticalEdges,yPositions);
  
  AliMUONSegmentTree segmentTree(yPositions);
  
  for ( Int_t i = 0; i <= polygonVerticalEdges.GetLast(); ++i )
  {
    const AliMUONSegment* edge = static_cast<const AliMUONSegment*>(polygonVerticalEdges.UncheckedAt(i));
    
    assert(edge!=0x0);
    
    if ( edge->IsLeftEdge() ) 
    {
      segmentTree.Contribution(edge->Bottom(),edge->Top());
      segmentTree.InsertInterval(edge->Bottom(),edge->Top());
    }
    else
    {
      segmentTree.DeleteInterval(edge->Bottom(),edge->Top());
      segmentTree.Contribution(edge->Bottom(),edge->Top());
    }
    
    AliMUONSegment e1(*edge);
    
    if ( i < polygonVerticalEdges.GetLast() ) 
    {
      const AliMUONSegment* next = static_cast<const AliMUONSegment*>(polygonVerticalEdges.UncheckedAt(i+1));
      e1 = *next;
    }

    if ( ( edge->IsLeftEdge() != e1.IsLeftEdge() ) ||
        ( !AliMUONSegment::AreEqual(edge->StartX(),e1.StartX() ) ) ||
        ( i == polygonVerticalEdges.GetLast() ) )
    {
      const TObjArray& stack = segmentTree.Stack();
      
      double x = edge->StartX();
      
      for ( Int_t j = 0; j <= stack.GetLast(); ++j )
      {
        AliMUONSegment* sj = static_cast<AliMUONSegment*>(stack.UncheckedAt(j));
        AliMUONSegment* s = new AliMUONSegment(x,sj->StartY(),x,sj->EndY());
        
        if  (s->IsAPoint()) 
        {
          delete s;
          continue;
        }
        
        if ( edge->IsLeftEdge() != s->IsLeftEdge() ) 
        {
          s->Set(x,sj->EndY(),x,sj->StartY());
        }
        contourVerticalEdges.Add(s);
      }
      segmentTree.ResetStack();
    }
  }
}

//_____________________________________________________________________________
void 
AliMUONContourMaker::VerticalToHorizontal(const TObjArray& polygonVerticalEdges,
                                          TObjArray& horizontalEdges) const
{
  /// Deduce the set of horizontal edges from the vertical edges
  /// Output array horizontalEdges should be empty before calling this method
  
  AliCodeTimerAuto("");
  
  TObjArray points; // array of AliMUONPointWithRef
  points.SetOwner(kTRUE);
  
  SortPoints(polygonVerticalEdges,points);
  
  for ( Int_t k = 0; k < (points.GetLast()+1)/2; ++k )
  {
    const AliMUONPointWithRef* p1 = static_cast<AliMUONPointWithRef*>(points.UncheckedAt(k*2));
    const AliMUONPointWithRef* p2 = static_cast<AliMUONPointWithRef*>(points.UncheckedAt(k*2+1));
    
    const AliMUONSegment* refEdge = static_cast<const AliMUONSegment*>(polygonVerticalEdges.UncheckedAt(p1->Ref()));
    
    // (p1,p2) is the horizontal edge.
    // refEdge is used to deduce the orientation of (p1,p2)
    
    if ( AliMUONSegment::AreEqual(p1->X(),refEdge->EndX()) && AliMUONSegment::AreEqual(p1->Y(),refEdge->EndY()) )
//    if ( AreEqual(p1,refEdge->End()) )
    {
      horizontalEdges.Add(new AliMUONSegment(p1->X(),p1->Y(),p2->X(),p2->Y()));
    }
    else
    {
      horizontalEdges.Add(new AliMUONSegment(p2->X(),p2->Y(),p1->X(),p1->Y()));
    }
  }
}
Commit	Line	Data
0b936dc0	1	/**************************************************************************
	2	* Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. *
	3	* *
	4	* Author: The ALICE Off-line Project. *
	5	* Contributors are mentioned in the code where appropriate. *
	6	* *
	7	* Permission to use, copy, modify and distribute this software and its *
	8	* documentation strictly for non-commercial purposes is hereby granted *
	9	* without fee, provided that the above copyright notice appears in all *
	10	* copies and that both the copyright notice and this permission notice *
	11	* appear in the supporting documentation. The authors make no claims *
	12	* about the suitability of this software for any purpose. It is *
	13	* provided "as is" without express or implied warranty. *
	14	**************************************************************************/
	15
	16	// $Id$
	17
	18	///
	19	/// Maker/merger of contours. Can create contour from a set polygons or
	20	/// merger a set of contours into a single one.
	21	///
	22	/// This is based on (one of the) algorithm found in
	23	/// Diane L. Souvaine and Iliana Bjorling-Sachs,
	24	/// Proceedings of the IEEE, Vol. 80, No. 9, September 1992, p. 1449
	25	///
	26	/// Note that besides the AliMUON prefix, nothing is really MUON specific
	27	/// in this class...
	28	///
	29	/// \author Laurent Aphecetche, Subatech
	30	///
	31
	32	#include "AliMUONContourMaker.h"
	33
	34	#include "AliCodeTimer.h"
	35	#include "AliLog.h"
	36	#include "AliMUONContour.h"
	37	#include "AliMUONPointWithRef.h"
	38	#include "AliMUONPolygon.h"
	39	#include "AliMUONSegment.h"
	40	#include "AliMUONSegmentTree.h"
	41	#include "Riostream.h"
	42	#include "TArrayD.h"
	43	#include "TMath.h"
	44	#include <cassert>
	45
	46	/// \cond CLASSIMP
	47	ClassImp(AliMUONContourMaker)
	48	/// \endcond
	49
	50	namespace
	51	{
	52	void PrintSegments(const TObjArray& array)
	53	{
	54	TIter next(&array);
	55	AliMUONSegment* s;
	56	Int_t i(0);
	57	while ( ( s = static_cast<AliMUONSegment*>(next()) ) )
	58	{
	59	cout << Form("i=%d %s",i,s->AsString()) << endl;
	60	++i;
	61	}
	62	}
	63	}
	64
65	//_____________________________________________________________________________
66	AliMUONContourMaker::AliMUONContourMaker()
67	{
68	}
69
70	//_____________________________________________________________________________
71	AliMUONContourMaker::~AliMUONContourMaker()
72	{
73	}
74
75	//_____________________________________________________________________________
76	AliMUONContour*
77	AliMUONContourMaker::CreateContour(const TObjArray& polygons, const char* name) const
78	{
79	/// Create the contour of the polygon array
80	/// and get back the intermediate verticals and horizontal segments
81	/// both arrays are arrays of AliMUONSegment objects.
82
83	AliCodeTimerAuto("");
84
85	if ( polygons.IsEmpty() ) return 0x0; // protection against user error...
86
87	// Sanity check : insure that all polygons are oriented counter-clockwise
88	TIter next(&polygons);
89	AliMUONPolygon* pol;
90	while ( ( pol = static_cast<AliMUONPolygon*>(next()) ) )
91	{
92	if ( !pol->IsCounterClockwiseOriented() )
93	{
94	AliError(Form("Got a clockwise oriented polygon in CreateContour(%s). That's not OK !",name));
95	StdoutToAliError(polygons.Print());
96	return 0x0;
97	}
98	}
99
100	AliMUONContour* contour(0x0);
101
102	if ( polygons.GetLast() == 0 )
103	{
104	AliCodeTimerAuto("Trivial case");
105	contour = new AliMUONContour(name);
106	pol = static_cast<const AliMUONPolygon*>(polygons.First());
107	contour->Add(*pol);
108	contour->AssertOrientation();
109	return contour;
110	}
111
112	TObjArray polygonVerticalEdges; // arrray of AliMUONSegment objects
113	polygonVerticalEdges.SetOwner(kTRUE);
114	// get vertical edges of input polygons
115	GetVerticalEdges(polygons,polygonVerticalEdges);
116
117	// sort them in ascending x order
118	// if same x, insure that left edges are before right edges
119	// within same x, order by increasing bottommost y (see AliMUONSegment::Compare method)
120	polygonVerticalEdges.Sort();
121
122	if ( polygonVerticalEdges.GetLast()+1 < 2 )
123	{
124	AliError(Form("Got too few edges here for createContour %s",name));
125	polygons.Print();
126	TObject* o(0x0);
127	o->Print();
128	}
129
130	// Find the vertical edges of the merged contour. This is the meat of the algorithm...
131	TObjArray contourVerticalEdges;
132	contourVerticalEdges.SetOwner(kTRUE);
133	Sweep(polygonVerticalEdges,contourVerticalEdges);
134
135	TObjArray horizontals;
136	horizontals.SetOwner(kTRUE);
137	VerticalToHorizontal(contourVerticalEdges,horizontals);
138
139	contour = FinalizeContour(contourVerticalEdges,horizontals);
140
141	if ( contour && name ) contour->SetName(name);
142
143	return contour;
144	}
145
146	//_____________________________________________________________________________
147	AliMUONContour*
148	AliMUONContourMaker::FinalizeContour(const TObjArray& verticals,
149	const TObjArray& horizontals) const
150	{
151	/// For a list of vertical and horizontal edges, we build the final
152	/// contour object.
153
154	AliCodeTimerAuto("");
155
156	TObjArray all; // array of AliMUONSegment
157	TObjArray inorder; // array of AliMUONSegment
158
159	all.SetOwner(kFALSE);
160	inorder.SetOwner(kFALSE);
161
162	for ( Int_t i = 0; i <= verticals.GetLast(); ++i )
163	{
164	all.Add(verticals.UncheckedAt(i));
165	all.Add(horizontals.UncheckedAt(i));
166	}
167
168	Int_t i(0);
169
170	AliMUONContour* contour = new AliMUONContour;
171
172	int total(0);
173
174	while ( !all.IsEmpty() )
175	{
176	total++;
177
178	if ( total > 1000 )
179	{
180	AliError("Total 1000 reached !!!!");
181	return 0x0;
182	}
183
184	AliMUONSegment* si = static_cast<AliMUONSegment*>(all.UncheckedAt(i));
185	inorder.Add(si);
186	const AliMUONSegment* all0 = static_cast<const AliMUONSegment*>(all.First());
187	if ( i != 0 && AliMUONSegment::AreEqual(si->EndX(),all0->StartX()) && AliMUONSegment::AreEqual(si->EndY(),all0->StartY()) )
188	{
189	Int_t n(-1);
190
191	AliMUONPolygon polygon(inorder.GetLast()+2);
192
193	// we got a cycle. Add it to the contour
194	for ( Int_t j = 0; j <= inorder.GetLast(); ++j )
195	{
196	AliMUONSegment* s = static_cast<AliMUONSegment*>(inorder.UncheckedAt(j));
197	polygon.SetVertex(++n,s->StartX(),s->StartY());
198	all.Remove(s);
199	}
200
201	all.Compress();
202
203	polygon.Close();
204
205	contour->Add(polygon);
206
207	if ( ! all.IsEmpty() )
208	{
209	i = 0;
210	inorder.Clear();
211	}
212	continue;
213	}
214
215	for ( Int_t j = 0; j <= all.GetLast(); ++j)
216	{
217	if ( j != i )
218	{
219	const AliMUONSegment* sj = static_cast<const AliMUONSegment*>(all.UncheckedAt(j));
220	if ( AliMUONSegment::AreEqual(si->EndX(),sj->StartX()) && AliMUONSegment::AreEqual(si->EndY(),sj->StartY()))
221	{
222	i = j;
223	break;
224	}
225	}
226	}
227	}
228
229	contour->AssertOrientation(kTRUE);
230	return contour;
231	}
232
233
234	//_____________________________________________________________________________
235	void
236	AliMUONContourMaker::GetVerticalEdges(const TObjArray& polygons, TObjArray& polygonVerticalEdges) const
237	{
238	/// From an array of polygons, extract the list of vertical edges.
239	/// Output array polygonVerticalEdges should be empty before calling.
240
241	AliCodeTimerAuto("");
242
243	for ( Int_t i = 0; i <= polygons.GetLast(); ++i )
244	{
245	const AliMUONPolygon* g = static_cast<const AliMUONPolygon*>(polygons.UncheckedAt(i));
246	for ( Int_t j = 0; j < g->NumberOfVertices()-1; ++j )
247	{
248	if ( AliMUONSegment::AreEqual(g->X(j),g->X(j+1)) ) // segment is vertical
249	{
250	polygonVerticalEdges.Add(new AliMUONSegment(g->X(j),g->Y(j),g->X(j+1),g->Y(j+1)));
251	}
252	}
253	}
254	}
255
256
257	//_____________________________________________________________________________
258	void
259	AliMUONContourMaker::GetYPositions(const TObjArray& polygonVerticalEdges,
260	TArrayD& yPositions) const
261	{
262	/// Fill the array yPositions with the different y positions found in
263	/// polygonVerticalEdges
264
265	AliCodeTimerAuto("");
266
267	Double_t* y = new Double_t[polygonVerticalEdges.GetSize()*2];
268	Int_t n(0);
269
270	for ( Int_t i = 0; i < polygonVerticalEdges.GetLast(); ++i )
271	{
272	AliMUONSegment* s = static_cast<AliMUONSegment*>(polygonVerticalEdges.UncheckedAt(i));
273	y[n] = s->StartY();
274	y[n+1] = s->EndY();
275	n += 2;
276	}
277	Int_t* ix = new Int_t[n+1];
278
279	TMath::Sort(n,y,ix,kFALSE);
280
281	yPositions.Set(n+1);
282
283	Int_t u(0);
284	Double_t x(FLT_MAX);
285
286	for ( Int_t i = 0; i < n; ++i )
287	{
288	if ( y[ix[i]] != x )
289	{
290	yPositions[u] = y[ix[i]];
291	x = y[ix[i]];
292	++u;
293	}
294	}
295
296	yPositions.Set(u);
297
298	delete[] ix;
299	delete[] y;
300
301	}
302
303	//_____________________________________________________________________________
304	AliMUONContour*
305	AliMUONContourMaker::MergeContour(const TObjArray& contours, const char* name) const
306	{
307	/// Merge all the polygons of all contours into a single contour
308
309	AliCodeTimerAuto("");
310
311	TObjArray polygons;
312	polygons.SetOwner(kTRUE);
313
314	TIter next(&contours);
315	AliMUONContour* contour;
316	while ( ( contour = static_cast<AliMUONContour*>(next()) ) )
317	{
318	const TObjArray* contourPolygons = contour->Polygons();
319	TIter nextPol(contourPolygons);
320	AliMUONPolygon* pol;
321	while ( ( pol = static_cast<AliMUONPolygon*>(nextPol()) ) )
322	{
323	polygons.Add(new AliMUONPolygon(*pol));
324	}
325	}
326
327	if ( polygons.IsEmpty() ) return 0x0;
328
329	contour = CreateContour(polygons,name);
330
331	return contour;
332	}
333
334	//_____________________________________________________________________________
335	void
336	AliMUONContourMaker::SortPoints(const TObjArray& polygonVerticalEdges,
337	TObjArray& sortedPoints) const
338	{
339	/// Sort the point of the vertical edges in ascending order, first on ordinate,
340	/// then on abcissa, and put them in output vector sortedPoints.
341	/// Output array sortedPoints should be empty before calling this method.
342
343	AliCodeTimerAuto("");
344
345	for ( Int_t i = 0; i <= polygonVerticalEdges.GetLast(); ++i )
346	{
347	const AliMUONSegment* e = static_cast<const AliMUONSegment*>(polygonVerticalEdges.UncheckedAt(i));
348	sortedPoints.Add(new AliMUONPointWithRef(e->StartX(),e->StartY(),i));
349	sortedPoints.Add(new AliMUONPointWithRef(e->EndX(),e->EndY(),i));
350	// note that we keep track of the original edge, which is used
351	// later on to deduce orientation of horizontal edges.
352	}
353
354	sortedPoints.Sort();
355	}
356
357	//_____________________________________________________________________________
358	void
359	AliMUONContourMaker::Sweep(const TObjArray& polygonVerticalEdges,
360	TObjArray& contourVerticalEdges) const
361	{
362	/// This is the meat of the algorithm of the contour merging...
363
364	AliCodeTimerAuto("");
365
366	TArrayD yPositions;
367	GetYPositions(polygonVerticalEdges,yPositions);
368
369	AliMUONSegmentTree segmentTree(yPositions);
370
371	for ( Int_t i = 0; i <= polygonVerticalEdges.GetLast(); ++i )
372	{
373	const AliMUONSegment* edge = static_cast<const AliMUONSegment*>(polygonVerticalEdges.UncheckedAt(i));
374
375	assert(edge!=0x0);
376
377	if ( edge->IsLeftEdge() )
378	{
379	segmentTree.Contribution(edge->Bottom(),edge->Top());
380	segmentTree.InsertInterval(edge->Bottom(),edge->Top());
381	}
382	else
383	{
384	segmentTree.DeleteInterval(edge->Bottom(),edge->Top());
385	segmentTree.Contribution(edge->Bottom(),edge->Top());
386	}
387
388	AliMUONSegment e1(*edge);
389
390	if ( i < polygonVerticalEdges.GetLast() )
391	{
392	const AliMUONSegment* next = static_cast<const AliMUONSegment*>(polygonVerticalEdges.UncheckedAt(i+1));
393	e1 = *next;
394	}
395
396	if ( ( edge->IsLeftEdge() != e1.IsLeftEdge() ) \|\|
397	( !AliMUONSegment::AreEqual(edge->StartX(),e1.StartX() ) ) \|\|
398	( i == polygonVerticalEdges.GetLast() ) )
399	{
400	const TObjArray& stack = segmentTree.Stack();
401
402	double x = edge->StartX();
403
404	for ( Int_t j = 0; j <= stack.GetLast(); ++j )
405	{
406	AliMUONSegment* sj = static_cast<AliMUONSegment*>(stack.UncheckedAt(j));
407	AliMUONSegment* s = new AliMUONSegment(x,sj->StartY(),x,sj->EndY());
408
409	if (s->IsAPoint())
410	{
411	delete s;
412	continue;
413	}
414
415	if ( edge->IsLeftEdge() != s->IsLeftEdge() )
416	{
417	s->Set(x,sj->EndY(),x,sj->StartY());
418	}
419	contourVerticalEdges.Add(s);
420	}
421	segmentTree.ResetStack();
422	}
423	}
424	}
425
426	//_____________________________________________________________________________
427	void
428	AliMUONContourMaker::VerticalToHorizontal(const TObjArray& polygonVerticalEdges,
429	TObjArray& horizontalEdges) const
430	{
431	/// Deduce the set of horizontal edges from the vertical edges
432	/// Output array horizontalEdges should be empty before calling this method
433
434	AliCodeTimerAuto("");
435
436	TObjArray points; // array of AliMUONPointWithRef
437	points.SetOwner(kTRUE);
438
439	SortPoints(polygonVerticalEdges,points);
440
441	for ( Int_t k = 0; k < (points.GetLast()+1)/2; ++k )
442	{
443	const AliMUONPointWithRef* p1 = static_cast<AliMUONPointWithRef>(points.UncheckedAt(k2));
444	const AliMUONPointWithRef* p2 = static_cast<AliMUONPointWithRef>(points.UncheckedAt(k2+1));
445
446	const AliMUONSegment* refEdge = static_cast<const AliMUONSegment*>(polygonVerticalEdges.UncheckedAt(p1->Ref()));
447
448	// (p1,p2) is the horizontal edge.
449	// refEdge is used to deduce the orientation of (p1,p2)
450
451	if ( AliMUONSegment::AreEqual(p1->X(),refEdge->EndX()) && AliMUONSegment::AreEqual(p1->Y(),refEdge->EndY()) )
452	// if ( AreEqual(p1,refEdge->End()) )
453	{
454	horizontalEdges.Add(new AliMUONSegment(p1->X(),p1->Y(),p2->X(),p2->Y()));
455	}
456	else
457	{
458	horizontalEdges.Add(new AliMUONSegment(p2->X(),p2->Y(),p1->X(),p1->Y()));
459	}
460	}
461	}
462