// Copyright (C) 2010, Guy Barrand. All rights reserved.
// See the file tools.license for terms.

#ifndef tools_clist_contour
#define tools_clist_contour

// G.Barrand : inline version of the one found in Lib of OSC 16.11.
//             This code is not mine and I keep it "as it is".

// Inheritance :
#include "ccontour"

#include <list>
#include <ostream>
#include <iomanip> //std::setprecision

namespace tools {

// a list of point index referring to the secondary grid
// Let i the index of a point,
typedef std::list<unsigned int> cline_strip;
typedef std::list<cline_strip*> cline_strip_list;
typedef std::vector<cline_strip_list> cline_strip_list_vector;

class clist_contour : public ccontour
{
public: //ccontour
	// Adding segment to line strips
	// See ccontour::ExportLine for further details
	virtual void ExportLine(int iPlane,int x1, int y1, int x2, int y2);

public:
	clist_contour();
	virtual ~clist_contour(){CleanMemory();}
protected: //G.Barrand
        clist_contour(const clist_contour& a_from):ccontour(a_from){}
private: //G.Barrand
        clist_contour& operator=(const clist_contour&){return *this;}
public:
	// retreiving list of line strip for the i-th contour
	cline_strip_list* get_lines(unsigned int iPlane);
	// Basic algorithm to concatanate line strip. Not optimized at all !
	bool compact_strips ();
	// generate contour strips
	virtual void generate();
protected: //G.Barrand

	// Initializing memory
	virtual void InitMemory();
	// Cleaning memory and line strips
	virtual void CleanMemory();

	/// debuggin
	void DumpPlane(unsigned int iPlane) const;

	// Area given by this function can be positive or negative depending on the winding direction of the contour.
	double Area(cline_strip* Line);

	double EdgeWeight(cline_strip* pLine, double R);
	//bool   PrintContour(std::ostream& a_out);
protected:
	// Merges pStrip1 with pStrip2 if they have a common end point
	bool MergeStrips(cline_strip* pStrip1, cline_strip* pStrip2);
	// Merges the two strips with a welding threshold.
	bool ForceMerge(cline_strip* pStrip1, cline_strip* pStrip2,double);
	// returns true if contour is touching boundary
	bool OnBoundary(cline_strip* pStrip);
        // L.Garnier : check specials case for CompactStrip
        bool SpecialCompactStripCase(double,double,double,double,double);

private:
	// array of line strips
	cline_strip_list_vector m_vStripLists;
        typedef unsigned int UINT;

private:
        static const char* _TT(const char* what) {return what;}

        static void _TRACE_(const char* /*a_fmt*/,...) {
        }
        static void _PROBLEM_(const char* what) {::printf("%s",what);}

	static bool _ASSERT_RET_(bool what,const char* cmt) {
          if(!(what)) {
            ::printf("debug : ListContour : assert failure in %s\n",cmt);
            return false;
          }
          return true;
	}

	static bool _ASSERT_MERGE_RET_(bool what,const char* cmt,cline_strip* pStrip2) {
          if(!(what)) {
            ::printf("debug : ListContour : assert failure in %s\n",cmt);
            pStrip2->clear();
            return false;
          }
          return true;
        }
};


// implementation :
inline clist_contour::clist_contour()
: ccontour()
{
}

inline void clist_contour::generate()
{
	// generate line strips
	ccontour::generate();
	// compact strips
	compact_strips ();
}

inline void clist_contour::InitMemory()
{
	ccontour::InitMemory();

	cline_strip_list::iterator pos;
	cline_strip* pStrip;

	if (!m_vStripLists.empty())
	{
		UINT i;
		// reseting lists
		_ASSERT_(m_vStripLists.size() == get_number_of_planes(),"clist_contour::InitMemory::0");
		for (i=0;i<get_number_of_planes();i++)
		{
			for (pos = m_vStripLists[i].begin(); pos!=m_vStripLists[i].end() ; pos++)
			{
				pStrip=(*pos);
				_ASSERTP_(pStrip,"clist_contour::InitMemory::1");

				pStrip->clear();
				delete pStrip;
			}
			m_vStripLists[i].clear();
		}
	}
	else
		m_vStripLists.resize(get_number_of_planes());
}

inline void clist_contour::CleanMemory()
{
	ccontour::CleanMemory();

	cline_strip_list::iterator pos;
	cline_strip* pStrip;
	UINT i;

	// reseting lists
	for (i=0;i<m_vStripLists.size();i++) //G.Barrand
	{
		for (pos=m_vStripLists[i].begin(); pos!=m_vStripLists[i].end();pos++)
		{
			pStrip=(*pos);
			_ASSERTP_(pStrip,"clist_contour::CleanMemory");
			pStrip->clear();
			delete pStrip;
		}
		m_vStripLists[i].clear();
	}
}

inline void clist_contour::ExportLine(int iPlane,int x1, int y1, int x2, int y2)
{
	_ASSERT_(iPlane>=0,"clist_contour::ExportLine::0");
	_ASSERT_(iPlane<(int)get_number_of_planes(),"clist_contour::ExportLine::1");

	// check that the two points are not at the beginning or end of the  some line strip
	UINT i1=y1*(m_iColSec+1)+x1;
	UINT i2=y2*(m_iColSec+1)+x2;

	cline_strip* pStrip;

	cline_strip_list::iterator pos;
	bool added = false;
	for(pos=m_vStripLists[iPlane].begin(); pos!=m_vStripLists[iPlane].end() && !added; pos++)
	{
		pStrip=(*pos);
		_ASSERTP_(pStrip,"clist_contour::ExportLine::2");
		// check if points are appendable to this strip
		if (i1==pStrip->front())
		{
			pStrip->insert(pStrip->begin(),i2);
			return;
		}
		if (i1==pStrip->back())
		{
			pStrip->insert(pStrip->end(),i2);
			return;
		}
		if (i2==pStrip->front())
		{
			pStrip->insert(pStrip->begin(),i1);
			return;
		}
		if (i2==pStrip->back())
		{
			pStrip->insert(pStrip->end(),i1);
			return;
		}
	}

	// segment was not part of any line strip, creating new one
	pStrip=new cline_strip;
	pStrip->insert(pStrip->begin(),i1);
	pStrip->insert(pStrip->end(),i2);
	m_vStripLists[iPlane].insert(m_vStripLists[iPlane].begin(),pStrip);
}

inline bool clist_contour::ForceMerge(cline_strip* pStrip1, cline_strip* pStrip2,double aHeight)
{

	cline_strip::iterator pos;
	cline_strip::reverse_iterator rpos;

	if (pStrip2->empty())
		return false;

	double x[4], y[4], weldDist;
	int index;
	index = pStrip1->front();
	x[0] = get_xi(index);
	y[0] = get_yi(index);
	index = pStrip1->back();
	x[1] = get_xi(index);
	y[1] = get_yi(index);
	index = pStrip2->front();
	x[2] = get_xi(index);
	y[2] = get_yi(index);
	index = pStrip2->back();
	x[3] = get_xi(index);
	y[3] = get_yi(index);

	weldDist = 10*(m_dDx*m_dDx+m_dDy*m_dDy);

	if (((x[1]-x[2])*(x[1]-x[2])+(y[1]-y[2])*(y[1]-y[2])< weldDist)
            || SpecialCompactStripCase(x[1],x[2],y[1],y[2],aHeight)) // L.Garnier

    {
		for (pos=pStrip2->begin(); pos!=pStrip2->end();pos++)
		{
			index=(*pos);
			if(!_ASSERT_RET_(index>=0,"clist_contour::ForceMerge::0")) return false;
			pStrip1->insert(pStrip1->end(),index);
		}
		pStrip2->clear();
		return true;
    }

	if (((x[3]-x[0])*(x[3]-x[0])+(y[3]-y[0])*(y[3]-y[0])< weldDist)
            || SpecialCompactStripCase(x[3],x[0],y[3],y[0],aHeight)) // L.Garnier
    {
		for (rpos=pStrip2->rbegin(); rpos!=pStrip2->rend();rpos++)
		{
			index=(*rpos);
			if(!_ASSERT_RET_(index>=0,"clist_contour::ForceMerge::1")) return false;
			pStrip1->insert(pStrip1->begin(),index);
		}
		pStrip2->clear();
		return true;
    }

	if (((x[1]-x[3])*(x[1]-x[3])+(y[1]-y[3])*(y[1]-y[3])< weldDist)
            || SpecialCompactStripCase(x[1],x[3],y[1],y[3],aHeight)) // L.Garnier
    {
		for (rpos=pStrip2->rbegin(); rpos!=pStrip2->rend();rpos++)
		{
			index=(*rpos);
			if(!_ASSERT_RET_(index>=0,"clist_contour::ForceMerge::2")) return false;
			pStrip1->insert(pStrip1->end(),index);
		}
		pStrip2->clear();
		return true;
    }

	if (((x[0]-x[2])*(x[0]-x[2])+(y[0]-y[2])*(y[0]-y[2])< weldDist)
            || SpecialCompactStripCase(x[0],x[2],y[0],y[2],aHeight)) // L.Garnier
    {
		for (pos=pStrip2->begin(); pos!=pStrip2->end();pos++)
		{
			index=(*pos);
			if(!_ASSERT_RET_(index>=0,"clist_contour::ForceMerge::3")) return false;
			pStrip1->insert(pStrip1->begin(),index);
		}
		pStrip2->clear();
		return true;
    }

	return false;
}

inline bool clist_contour::MergeStrips(cline_strip* pStrip1, cline_strip* pStrip2)
{
	cline_strip::iterator pos;
	cline_strip::reverse_iterator rpos;
	if (pStrip2->empty())
		return false;

	int index;

	// debugging stuff
	if (pStrip2->front()==pStrip1->front())
    {
		// retreiving first element
		pStrip2->pop_front();
		// adding the rest to strip1
		for (pos=pStrip2->begin(); pos!=pStrip2->end();pos++)
		{
			index=(*pos);
			if(!_ASSERT_MERGE_RET_(index>=0,"clist_contour::MergeStrips::0",pStrip2)) return false;
			pStrip1->insert(pStrip1->begin(),index);
		}
		pStrip2->clear();
		return true;
    }

	if (pStrip2->front()==pStrip1->back())
    {
		pStrip2->pop_front();
		// adding the rest to strip1
		for (pos=pStrip2->begin(); pos!=pStrip2->end();pos++)
		{
			index=(*pos);
			if(!_ASSERT_MERGE_RET_(index>=0,"clist_contour::MergeStrips::1",pStrip2)) return false;
			pStrip1->insert(pStrip1->end(),index);
		}
		pStrip2->clear();
		return true;
    }

	if (pStrip2->back()==pStrip1->front())
    {
		pStrip2->pop_back();
		// adding the rest to strip1
		for (rpos=pStrip2->rbegin(); rpos!=pStrip2->rend();rpos++)
		{
			index=(*rpos);
			if(!_ASSERT_MERGE_RET_(index>=0,"clist_contour::MergeStrips::2",pStrip2)) return false;
			pStrip1->insert(pStrip1->begin(),index);
		}
		pStrip2->clear();
		return true;
    }

	if (pStrip2->back()==pStrip1->back())
    {
		pStrip2->pop_back();
		// adding the rest to strip1
		for (rpos=pStrip2->rbegin(); rpos!=pStrip2->rend();rpos++)
		{
			index=(*rpos);
			if(!_ASSERT_MERGE_RET_(index>=0,"clist_contour::MergeStrips::3",pStrip2)) return false;
			pStrip1->insert(pStrip1->end(),index);
		}
		pStrip2->clear();
		return true;
    }

	return false;
}

inline bool clist_contour::compact_strips ()
{
	cline_strip* pStrip;
	cline_strip* pStripBase = 0;
	UINT i;
	cline_strip_list::iterator pos,pos2;
	cline_strip_list newList;
	bool again, changed;

	const double weldDist = 10*(m_dDx*m_dDx+m_dDy*m_dDy);

	if(!_ASSERT_RET_(m_vStripLists.size() == get_number_of_planes(),"clist_contour::compact_strips ::0")) return false;
	for (i=0;i<get_number_of_planes();i++)
	{
		double planeHeight = get_plane(i);
		again=true;
		while(again)
		{
			// REPEAT COMPACT PROCESS UNTILL LAST PROCESS MAKES NO CHANGE

			again=false;
			// building compacted list
			if(!_ASSERT_RET_(newList.empty(),"clist_contour::compact_strips ::1")) return false;
			for (pos=m_vStripLists[i].begin(); pos!=m_vStripLists[i].end();pos++)
			{
				pStrip=(*pos);
				for (pos2=newList.begin(); pos2!=newList.end();pos2++)
				{
					pStripBase=(*pos2);
					changed=MergeStrips(pStripBase,pStrip);
					if (changed)
						again=true;
					if (pStrip->empty())
						break;
				}
				if (pStrip->empty())
					delete pStrip;
				else
					newList.insert(newList.begin(),pStrip);
			}


			// deleting old list
			m_vStripLists[i].clear();
			cline_strip* pStrip2;
			// Copying all
			for (pos2=newList.begin(); pos2 != newList.end(); pos2++)
			{
				pStrip2=(*pos2);
				cline_strip::iterator pos1 = pStrip2->begin(),pos3;
				while (pos1!=pStrip2->end())
				{
					pos3 = pos1;
					pos3++;
					if (pos3==pStrip2->end()) break; //G.Barrand
					if ( (*pos1) == (*pos3))
					{
					  /*G.Barrand : we can't compare with pStrip2->end() content.
						if ( (*pos3) != (*pStrip2->end()))
							pStrip2->erase(pos3);
						else
						{
							pStrip2->erase(pos3);
							break;
						}
					  */
   					  pStrip2->erase(pos3); //G.Barrand.
					}
					else
						pos1++;
				}

				if (pStrip2->size()!=1) 
					m_vStripLists[i].insert(m_vStripLists[i].begin(),pStrip2 );
				else
					delete pStrip2;
			}
			// emptying temp list
			newList.clear();

		} // OF WHILE(AGAIN) (LAST COMPACT PROCESS MADE NO CHANGES)


		if (m_vStripLists[i].empty())
			continue;
		///////////////////////////////////////////////////////////////////////
		// compact more
		int index,count;
		size_t Nstrip,j;

		Nstrip = m_vStripLists[i].size();
		std::vector<bool> closed(Nstrip);
		double x,y;

		// First let's find the open and closed lists in m_vStripLists
		for(pos2 = m_vStripLists[i].begin(), j=0, count=0; pos2 != m_vStripLists[i].end(); pos2++, j++)
		{
			pStrip = (*pos2);

			// is it open ?
			if (pStrip->front() != pStrip->back())
			{
				index = pStrip->front();
				x = get_xi(index); y = get_yi(index);
				index = pStrip->back();
				x -= get_xi(index); y -= get_yi(index);

				// is it "almost closed" ?
				if ((x*x+y*y < weldDist) ||
                                    SpecialCompactStripCase(get_xi(pStrip->front()), // L.Garnier
                                                            get_xi(pStrip->back()),
                                                            get_yi(pStrip->front()),
                                                            get_yi(pStrip->back()),
                                                            planeHeight))
                                {
                                        closed[j] = true;
                                        // close it !!! Added by L.Garnier
                                        pStrip->push_back(pStrip->front());
                                        //
                                }
				else
				{
					closed[j] = false;
					// updating not closed counter...
					count ++;
				}
			}
			else
				closed[j] = true;
		}

		// is there any open strip ?
		if (count > 1)
		{
			// Merge the open strips into NewList
			pos = m_vStripLists[i].begin();
			for(j=0;j<Nstrip;j++)
			{
				if (closed[j] == false )
				{
					pStrip = (*pos);
					newList.insert(newList.begin(),pStrip);
					pos = m_vStripLists[i].erase(pos);
				}
				else
					pos ++;
			}

			// are they open strips to process ?
			while(newList.size()>1)
			{
				pStripBase = newList.front();

				// merge the rest to pStripBase
				again = true;
				while (again)
				{
					again = false;
					pos = newList.begin();
					for(pos++; pos!=newList.end();)
					{
						pStrip = (*pos);
						changed = ForceMerge(pStripBase,pStrip,planeHeight);
						if (changed)
						{
							again = true;
							delete pStrip;
							pos = newList.erase(pos);
						}
						else
							pos ++;
					}
				} // while(again)

				index = pStripBase->front();
				x = get_xi(index); y = get_yi(index);
				index = pStripBase->back();
				x -= get_xi(index); y -= get_yi(index);
				// if pStripBase is closed or not

				if ((x*x+y*y < weldDist) ||
                                    SpecialCompactStripCase(get_xi(pStripBase->front()), // L.Garnier
                                                            get_xi(pStripBase->back()),
                                                            get_yi(pStripBase->front()),
                                                            get_yi(pStripBase->back()),
                                                            planeHeight))
                                {

                                  // close it !!! Added by L.Garnier
                                  if ((x!=0) || (y!=0)) {
                                    pStripBase->push_back(pStripBase->front());
                                  }
                                  //
                                  m_vStripLists[i].insert(m_vStripLists[i].begin(),pStripBase);
                                  newList.pop_front();
				}
				else
				{
					if (OnBoundary(pStripBase))
					{
						_TRACE_(_TT("# open strip ends on boundary, continue.\n"));
						m_vStripLists[i].insert(m_vStripLists[i].begin(),pStripBase);
						newList.pop_front();
					}
					else
					{
						_PROBLEM_(_TT("unpaird open strip at 1!\n"));
						//exit(0);
						return false;
					}
				}
			} // while(newList.size()>1);


			if (newList.size() ==1)
			{
				pStripBase = newList.front();
				index = pStripBase->front(); // L.Garnier
				x = get_xi(index); y = get_yi(index); // L.Garnier
				index = pStripBase->back(); // L.Garnier
				x -= get_xi(index); y -= get_yi(index); // L.Garnier

				// is it "almost closed", give last chance...5*weldDist
				if (x*x+y*y < 3*weldDist) // L.Garnier
				{
					m_vStripLists[i].insert(m_vStripLists[i].begin(),pStripBase);
					newList.pop_front();
				}
				else if (OnBoundary(pStripBase))
				{
					_TRACE_(_TT("# open strip ends on boundary, continue.\n"));
					m_vStripLists[i].insert(m_vStripLists[i].begin(),pStripBase);
					newList.pop_front();
				}
				else
				{
					_PROBLEM_(_TT("unpaird open strip at 2!\n"));
					DumpPlane(i);
					//exit(0);
					return false;
				}
			}

			newList.clear();

		}
		else if (count == 1)
		{
			pos = m_vStripLists[i].begin();
			for(j=0;j<Nstrip;j++)
			{
				if (closed[j] == false )
				{
					pStripBase = (*pos);
					break;
				}
				pos ++;
			}
			index = pStripBase->front(); // L.Garnier
			x = get_xi(index); y = get_yi(index); // L.Garnier
			index = pStripBase->back(); // L.Garnier
			x -= get_xi(index); y -= get_yi(index); // L.Garnier
       
			// is it "almost closed", give last chance...5*weldDist
			if (x*x+y*y < 2*weldDist) // L.Garnier
			{
			  //close it!!
			  pStripBase->push_back(pStripBase->front()); // L.Garnier
			}
			else if (OnBoundary(pStripBase))
			{
				_TRACE_(_TT("# open strip ends on boundary, continue.\n"));
				pStripBase->push_back(pStripBase->front()); // L.Garnier
			}
			else
			{
				_TRACE_(_TT("unpaird open strip at 3!"));
				DumpPlane(i);
				return false;  // L.Garnier
				//exit(0);
			}
			newList.clear();  // L.Garnier
		}
	}
        return true;
}


inline bool clist_contour::OnBoundary(cline_strip* pStrip)
{
	bool e1,e2;

	int index = pStrip->front();
	double x = get_xi(index), y = get_yi(index);
	if (x==m_pLimits[0] || x == m_pLimits[1] ||
		y == m_pLimits[2] || y == m_pLimits[3])
		e1 = true;
	else
		e1 = false;

	index = pStrip->back();
	x = get_xi(index); y = get_yi(index);
	if (x==m_pLimits[0] || x == m_pLimits[1] ||
		y == m_pLimits[2] || y == m_pLimits[3])
		e2 = true;
	else
		e2 = false;

	return (e1 && e2);
}

inline void clist_contour::DumpPlane(UINT iPlane) const
{
	cline_strip_list::const_iterator pos;
	UINT i;
	cline_strip* pStrip;

	/*_ASSERT_(iPlane>=0,"clist_contour::DumpPlane");*/
	_ASSERT_(iPlane<get_number_of_planes(),"clist_contour::DumpPlane::0");
	_TRACE_(_TT("Level : %d"),get_plane(iPlane));

	_TRACE_(_TT("Number of strips : %d\r\n"),m_vStripLists[iPlane].size());
	_TRACE_(_TT("i np start end xstart ystart xend yend\r\n"));
	for (pos = m_vStripLists[iPlane].begin(), i=0; pos != m_vStripLists[iPlane].end(); pos++, i++)
	{
		pStrip=*pos;
		_ASSERTP_(pStrip,"clist_contour::DumpPlane::1");
		_TRACE_(_TT("%d %d %d %d %g %g %g %g\r\n"),i,pStrip->size(),pStrip->front(),pStrip->back(),
			get_xi(pStrip->front()),get_yi(pStrip->front()),
			get_xi(pStrip->back()),get_yi(pStrip->back()) );
	}
}

inline double clist_contour::Area(cline_strip* Line)
{
	// if Line is not closed, return 0;

	double Ar = 0, x, y, x0,y0,x1, y1;
	int index;

	cline_strip::iterator pos;
	pos = Line->begin();
	index = (*pos);
	x0 = x =  get_xi(index);
	y0 = y =  get_yi(index);

	pos ++;

	for(;pos!=Line->end();pos++)
	{
		index = (*pos);
		x1 = get_xi(index);
		y1 = get_yi(index);
		// Ar += (x1-x)*(y1+y);
		Ar += (y1-y)*(x1+x)-(x1-x)*(y1+y);
		x = x1;
		y = y1;

	}


	//Ar += (x0-x)*(y0+y);
	Ar += (y0-y)*(x0+x)-(x0-x)*(y0+y);
	// if not closed curve, return 0;
	if ((x0-x)*(x0-x) + (y0-y)*(y0-y)>20*(m_dDx*m_dDx+m_dDy*m_dDy))
	{
		Ar = 0;
		_TRACE_(_TT("# open curve!\n"));
	}
	//else   Ar /= -2;
	else Ar/=4;
	// result is \int ydex/2 alone the implicit direction.
	return Ar;
}

inline double clist_contour:: EdgeWeight(cline_strip* pLine, double R)
{
	cline_strip::iterator pos;
	int count = 0,index;
	double x,y;
	for(pos = pLine->begin(); pos!=pLine->end(); pos++)
	{
		index = (*pos);
		x = get_xi(index);
		y = get_yi(index);
		if (fabs(x) > R || fabs(y) > R)
			count ++;
	}
	return (double)count/pLine->size();
}

//G.Barrand : from .h to .cxx to avoid _ASSERT_ in .h
inline cline_strip_list* clist_contour::get_lines(unsigned int iPlane)	{
  /*_ASSERT_(iPlane>=0);*/
  _ASSERT_(iPlane<get_number_of_planes(),"clist_contour::get_lines");
  return &m_vStripLists[iPlane];
}

// Added by L.Garnier
inline bool clist_contour::SpecialCompactStripCase(double aXfront,double aXback,double aYfront,double aYback,double actualHeight)
{
  // To solve the case of a list of strips
  // which appeared to be open but should correspond to a closed
  // contour.
  //  With the today generate() algorithm, it appears that we fall
  // on this case when the begin and end points
  // are on a horizontal or vertical line.
  // (case where front()->x == back()->x or front()->y == back()->y).
  //  We try to detect in this method this situation and decide to close
  // or not the line. To do that we check the heigth of intermediate
  // points to see if there are on the same contour; if so we close
  // the line (and return true), if not we do nothing (and return false).

  // check if we could realy close it
  float marge = 1; // *m_dDy or *m_dDx. 1 seems to be good and normal, but why
                   // not 2 in certain cases???

  double distToNext =0;
  // try to get the correct hight
  if (get_plane(0)>= actualHeight) {
    return false;
  }
  if (get_number_of_planes() >1){
    distToNext = get_plane(1)-get_plane(0);
  } else {
    return false;
  }

  if ((aYback-aYfront) == 0) {
    double temp;
    double av;
    double eg;
    double ap;

    if (aXfront==m_pLimits[0] && aXback == m_pLimits[1]) return false;
    if (aXfront==m_pLimits[1] && aXback == m_pLimits[0]) return false;

    if (aXfront > aXback ) {
      temp = aXfront;
      aXfront = aXback;
      aXback = temp;
    }
    for(double check=aXfront+m_dDx;
        check<aXback;
        check+=m_dDx) {
      av = ((*m_pFieldFcn)(check,aYback-marge*m_dDy,m_pFieldFcnData)-actualHeight);
      eg = ((*m_pFieldFcn)(check,aYback,m_pFieldFcnData)-actualHeight);
      ap = ((*m_pFieldFcn)(check,aYback+marge*m_dDy,m_pFieldFcnData)-actualHeight);

      if ((av>distToNext) && (ap>distToNext) && (eg>distToNext)) {
        return false;
      } else if ((av<0) && (ap<0) && (eg<0)) {
        return false;
      }
    }
    return true;
  } else if ((aXback-aXfront) == 0) {
    double temp;
    double av;
    double eg;
    double ap;
    if (aYfront==m_pLimits[3] && aYback == m_pLimits[2]) return false;
    if (aYfront==m_pLimits[2] && aYback == m_pLimits[3]) return false;

    if (aYfront > aYback ) {
      temp = aYfront;
      aYfront = aYback;
      aYback = temp;
    }

    for(double check=aYfront+m_dDy;
        check<aYback;
        check+=m_dDy) {
      av = ((*m_pFieldFcn)(aXback-marge*m_dDx,check,m_pFieldFcnData)-actualHeight);
      eg = ((*m_pFieldFcn)(aXback,check,m_pFieldFcnData)-actualHeight);
      ap = ((*m_pFieldFcn)(aXback+marge*m_dDx,check,m_pFieldFcnData)-actualHeight);
      if ((av>distToNext) && (ap>distToNext) && (eg>distToNext)) {
        return false;
      } else if ((av<0) && (ap<0) && (eg<0)) {
        return false;
      }
    }
    return true;
  }
  return false;
}

}

#endif
