/// <summary>
        /// Returns the routes (multiple lines or part polygons) either inside or
        /// outside the polygons provided. These are based on the intersections
        /// of the 2 polygons e.g. the routes / part polygons of one inside or
        /// outside the other.
        /// </summary>
        /// <param name="Poly1">The first polygon.</param>
        /// <param name="bP1RoutesInside">True if routes inside the second polygon are
        /// required for the first polygon.</param>
        /// <param name="Poly2">The second polygon.</param>
        /// <param name="bP2RoutesInside">True if routes inside the first polygon are
        /// required for the second polygon.</param>
        /// <param name="Routes1">Output. Set of lines for the first polygon.</param>
        /// <param name="Routes2">Output. Set of lines for the second polygon.</param>
        public static void GetRoutes(C2DPolyBase Poly1, bool bP1RoutesInside,
                                     C2DPolyBase Poly2, bool bP2RoutesInside,
                                     C2DLineBaseSetSet Routes1, C2DLineBaseSetSet Routes2)
        {
            // Set up a collection of intersected points, and corresponding indexes.
            var IntPoints = new C2DPointSet();
            var Indexes1  = new List <int>();
            var Indexes2  = new List <int>();

            // Use the line collections in each shape to find the intersections between them.
            Poly1.Lines.GetIntersections(Poly2.Lines, IntPoints,
                                         Indexes1, Indexes2,
                                         Poly1.BoundingRect, Poly2.BoundingRect);
            // Make a copy of the point set because this will be sorted by line index in the
            // Get routes function later. We need an unsorted set for each polygon.
            var IntPointsCopy = new C2DPointSet();

            IntPointsCopy.MakeCopy(IntPoints);

            // Find out whether the first poly starts inside the second.
            bool bP1StartInside = Poly2.Contains(Poly1.Lines[0].GetPointFrom());
            // Find out if poly 2 starts inside poly 1.
            bool bP2StartInside = Poly1.Contains(Poly2.Lines[0].GetPointFrom());

            if (IntPoints.Count == 0 && !bP1StartInside && !bP2StartInside)
            {
                return; // No interaction between the 2.
            }
            // Get the routes of poly 1 inside / outside the other, passing the unsorted
            // intersection points and polygon1 intersection indexes.
            Poly1.GetRoutes(IntPoints, Indexes1, Routes1, bP1StartInside, bP1RoutesInside);
            // Do the same for poly 2 but pass it the unsorted copy of the intersection points
            // So that they correspond to the indexes.
            Poly2.GetRoutes(IntPointsCopy, Indexes2, Routes2, bP2StartInside, bP2RoutesInside);
        }
        /// <summary>
        /// Returns the routes (multiple lines or part polygons) either inside or
        /// outside the polygons provided. These are based on the intersections
        /// of the 2 polygons e.g. the routes / part polygons of one inside or
        /// outside the other.
        /// </summary>
        /// <param name="Poly1">The first polygon.</param> 
        /// <param name="bP1RoutesInside">True if routes inside the second polygon are 
        /// required for the first polygon.</param> 
        /// <param name="Poly2">The second polygon.</param> 
        /// <param name="bP2RoutesInside">True if routes inside the first polygon are 
        /// required for the second polygon.</param> 
        /// <param name="Routes1">Output. Set of lines for the first polygon.</param> 
        /// <param name="Routes2">Output. Set of lines for the second polygon.</param> 
	    public static void GetRoutes(C2DPolyBase Poly1, bool bP1RoutesInside, 
				    C2DPolyBase Poly2, bool bP2RoutesInside, 
				    C2DLineBaseSetSet Routes1, C2DLineBaseSetSet Routes2)
        {
            // Set up a collection of intersected points, and corresponding indexes.
            C2DPointSet IntPoints = new C2DPointSet();
            List<int> Indexes1 = new List<int>();
            List<int> Indexes2 = new List<int>();
            // Use the line collections in each shape to find the intersections between them.
            Poly1.Lines.GetIntersections(Poly2.Lines, IntPoints,
                                                Indexes1, Indexes2,
                                        Poly1.BoundingRect, Poly2.BoundingRect);
            // Make a copy of the point set because this will be sorted by line index in the 
            // Get routes function later. We need an unsorted set for each polygon.
            C2DPointSet IntPointsCopy = new C2DPointSet();
            IntPointsCopy.MakeCopy(IntPoints);

            // Find out whether the first poly starts inside the second.
            bool bP1StartInside = Poly2.Contains(Poly1.Lines[0].GetPointFrom());
            // Find out if poly 2 starts inside poly 1.
            bool bP2StartInside = Poly1.Contains(Poly2.Lines[0].GetPointFrom());

            if (IntPoints.Count == 0 && !bP1StartInside && !bP2StartInside)
                return;	// No interaction between the 2.

            // Get the routes of poly 1 inside / outside the other, passing the unsorted
            // intersection points and polygon1 intersection indexes.
            Poly1.GetRoutes(IntPoints, Indexes1, Routes1, bP1StartInside, bP1RoutesInside);
            // Do the same for poly 2 but pass it the unsorted copy of the intersection points
            // So that they correspond to the indexes.
            Poly2.GetRoutes(IntPointsCopy, Indexes2, Routes2, bP2StartInside, bP2RoutesInside);
        }
        /// <summary>
        /// Gets the boolean operation with the other. e.g. union / intersection.
        /// </summary>
        /// <param name="Other">The other polygon.</param>
        /// <param name="HoledPolys">The set to recieve the result.</param>
        /// <param name="bThisInside">The flag to indicate routes inside.</param>
        /// <param name="bOtherInside">The flag to indicate routes inside for the other.</param>
        /// <param name="grid">The degenerate settings.</param>
        public void GetBoolean(C2DPolyBase Other, List <C2DHoledPolyBase> HoledPolys,
                               bool bThisInside, bool bOtherInside,
                               CGrid grid)
        {
            if (BoundingRect.Overlaps(Other.BoundingRect))
            {
                switch (grid.DegenerateHandling)
                {
                case CGrid.eDegenerateHandling.None:
                {
                    var Routes1 = new C2DLineBaseSetSet();
                    var Routes2 = new C2DLineBaseSetSet();
                    C2DPolyBase.GetRoutes(this, bThisInside, Other, bOtherInside, Routes1, Routes2);
                    Routes1.ExtractAllOf(Routes2);

                    if (Routes1.Count > 0)
                    {
                        // Add all the joining routes together to form closed routes
                        Routes1.MergeJoining();
                        // Set up some temporary polygons.
                        var Polygons = new List <C2DPolyBase>();
                        // Turn the routes into polygons.
                        for (var i = Routes1.Count - 1; i >= 0; i--)
                        {
                            if (Routes1[i].IsClosed(true) && Routes1[i].Count > 2)
                            {
                                Polygons.Add(new C2DPolyBase());
                                Polygons[Polygons.Count - 1].CreateDirect(Routes1[i]);
                            }
                            else
                            {
                                //   Debug.Assert(false);
                                grid.LogDegenerateError();
                            }
                        }


                        // Set up some temporary holed polygons
                        var NewComPolys = new C2DHoledPolyBaseSet();
                        // Turn the set of polygons into holed polygons. Not needed for intersection.
                        if (!(bThisInside && bOtherInside))
                        {
                            C2DHoledPolyBase.PolygonsToHoledPolygons(NewComPolys, Polygons);
                            if (NewComPolys.Count != 1)
                            {
                                //   Debug.Assert(false);
                                grid.LogDegenerateError();
                            }
                        }
                        else
                        {
                            for (var i = 0; i < Polygons.Count; i++)
                            {
                                HoledPolys.Add(new C2DHoledPolyBase(Polygons[i]));
                            }
                        }

                        // Now add them all to the provided set.
                        for (var i = 0; i < NewComPolys.Count; i++)
                        {
                            HoledPolys.Add(NewComPolys[i]);
                        }
                    }
                }
                break;

                case CGrid.eDegenerateHandling.RandomPerturbation:
                {
                    var OtherCopy = new C2DPolyBase(Other);
                    OtherCopy.RandomPerturb();
                    grid.DegenerateHandling = CGrid.eDegenerateHandling.None;
                    GetBoolean(OtherCopy, HoledPolys, bThisInside, bOtherInside, grid);
                    grid.DegenerateHandling = CGrid.eDegenerateHandling.RandomPerturbation;
                }
                break;

                case CGrid.eDegenerateHandling.DynamicGrid:
                {
                    var Rect = new C2DRect();
                    if (this.BoundingRect.Overlaps(Other.BoundingRect, Rect))
                    {
                        var dOldGrid = grid.GridSize;
                        grid.SetToMinGridSize(Rect, false);
                        grid.DegenerateHandling = CGrid.eDegenerateHandling.PreDefinedGrid;
                        GetBoolean(Other, HoledPolys, bThisInside, bOtherInside, grid);
                        grid.DegenerateHandling = CGrid.eDegenerateHandling.DynamicGrid;
                    }
                }
                break;

                case CGrid.eDegenerateHandling.PreDefinedGrid:
                {
                    var P1 = new C2DPolyBase(this);
                    var P2 = new C2DPolyBase(Other);
                    P1.SnapToGrid(grid);
                    P2.SnapToGrid(grid);
                    var V1            = new C2DVector(P1.BoundingRect.TopLeft, P2.BoundingRect.TopLeft);
                    var dPerturbation = grid.GridSize;                     // ensure it snaps back to original grid positions.
                    if (V1.i > 0)
                    {
                        V1.i = dPerturbation;
                    }
                    else
                    {
                        V1.i = -dPerturbation;          // move away slightly if possible
                    }
                    if (V1.j > 0)
                    {
                        V1.j = dPerturbation;
                    }
                    else
                    {
                        V1.j = -dPerturbation;     // move away slightly if possible
                    }
                    V1.i *= 0.411923;              // ensure it snaps back to original grid positions.
                    V1.j *= 0.313131;              // ensure it snaps back to original grid positions.

                    P2.Move(V1);
                    grid.DegenerateHandling = CGrid.eDegenerateHandling.None;
                    P1.GetBoolean(P2, HoledPolys, bThisInside, bOtherInside, grid);

                    for (var i = 0; i < HoledPolys.Count; i++)
                    {
                        HoledPolys[i].SnapToGrid(grid);
                    }

                    grid.DegenerateHandling = CGrid.eDegenerateHandling.PreDefinedGrid;
                }
                break;

                case CGrid.eDegenerateHandling.PreDefinedGridPreSnapped:
                {
                    var P2            = new C2DPolyBase(Other);
                    var V1            = new C2DVector(this.BoundingRect.TopLeft, P2.BoundingRect.TopLeft);
                    var dPerturbation = grid.GridSize;                     // ensure it snaps back to original grid positions.
                    if (V1.i > 0)
                    {
                        V1.i = dPerturbation;
                    }
                    else
                    {
                        V1.i = -dPerturbation;     // move away slightly if possible
                    }
                    if (V1.j > 0)
                    {
                        V1.j = dPerturbation;
                    }
                    else
                    {
                        V1.j = -dPerturbation;     // move away slightly if possible
                    }
                    V1.i *= 0.411923;              // ensure it snaps back to original grid positions.
                    V1.j *= 0.313131;              // ensure it snaps back to original grid positions.

                    P2.Move(V1);
                    grid.DegenerateHandling = CGrid.eDegenerateHandling.None;
                    GetBoolean(P2, HoledPolys, bThisInside, bOtherInside, grid);

                    for (var i = 0; i < HoledPolys.Count; i++)
                    {
                        HoledPolys[i].SnapToGrid(grid);
                    }
                    grid.DegenerateHandling = CGrid.eDegenerateHandling.PreDefinedGridPreSnapped;
                }
                break;
                }
            }
        }
        /// <summary>
        /// Returns the routes (multiple lines or part polygons) either inside or
        /// outside the polygons provided. These are based on the intersections
        /// of the 2 polygons e.g. the routes / part polygons of one inside or
        /// outside the other.
        /// </summary>
        /// <param name="Poly1">The first polygon.</param>
        /// <param name="bP1RoutesInside">True if routes inside the second polygon are
        /// required for the first polygon.</param>
        /// <param name="Poly2">The second polygon.</param>
        /// <param name="bP2RoutesInside">True if routes inside the first polygon are
        /// required for the second polygon.</param>
        /// <param name="Routes1">Output. Set of lines for the first polygon.</param>
        /// <param name="Routes2">Output. Set of lines for the second polygon.</param>
        /// <param name="CompleteHoles1">Output. Complete holes for the first polygon.</param>
        /// <param name="CompleteHoles2">Output. Complete holes for the second polygon.</param>
        /// <param name="grid">Contains the degenerate handling settings.</param>
        public static void GetRoutes(C2DHoledPolyBase Poly1, bool bP1RoutesInside,
                                     C2DHoledPolyBase Poly2, bool bP2RoutesInside,
                                     C2DLineBaseSetSet Routes1, C2DLineBaseSetSet Routes2,
                                     List <C2DPolyBase> CompleteHoles1, List <C2DPolyBase> CompleteHoles2,
                                     CGrid grid)
        {
            if (Poly1.Rim.Lines.Count == 0 || Poly2.Rim.Lines.Count == 0)
            {
                Debug.Assert(false, "Polygon with no lines");
                return;
            }

            C2DPointSet IntPointsTemp = new C2DPointSet();
            C2DPointSet IntPointsRim1 = new C2DPointSet();
            C2DPointSet IntPointsRim2 = new C2DPointSet();
            List <int>  IndexesRim1   = new List <int>();
            List <int>  IndexesRim2   = new List <int>();


            List <C2DPointSet> IntPoints1AllHoles = new List <C2DPointSet>();
            List <C2DPointSet> IntPoints2AllHoles = new List <C2DPointSet>();
            List <List <int> > Indexes1AllHoles   = new List <List <int> >();
            List <List <int> > Indexes2AllHoles   = new List <List <int> >();
            //    std::vector<C2DPointSet* > IntPoints1AllHoles, IntPoints2AllHoles;
            //   std::vector<CIndexSet*> Indexes1AllHoles, Indexes2AllHoles;

            int usP1Holes = Poly1.HoleCount;
            int usP2Holes = Poly2.HoleCount;

            // *** Rim Rim Intersections
            Poly1.Rim.Lines.GetIntersections(Poly2.Rim.Lines,
                                             IntPointsTemp, IndexesRim1, IndexesRim2,
                                             Poly1.Rim.BoundingRect, Poly2.Rim.BoundingRect);

            IntPointsRim1.AddCopy(IntPointsTemp);
            IntPointsRim2.ExtractAllOf(IntPointsTemp);

            // *** Rim Hole Intersections
            for (int i = 0; i < usP2Holes; i++)
            {
                Debug.Assert(IntPointsTemp.Count == 0);

                IntPoints2AllHoles.Add(new C2DPointSet());
                Indexes2AllHoles.Add(new List <int>());

                if (Poly1.Rim.BoundingRect.Overlaps(Poly2.GetHole(i).BoundingRect))
                {
                    Poly1.Rim.Lines.GetIntersections(Poly2.GetHole(i).Lines,
                                                     IntPointsTemp, IndexesRim1, Indexes2AllHoles[i],
                                                     Poly1.Rim.BoundingRect, Poly2.GetHole(i).BoundingRect);

                    IntPointsRim1.AddCopy(IntPointsTemp);
                    IntPoints2AllHoles[i].ExtractAllOf(IntPointsTemp);
                }
            }
            // *** Rim Hole Intersections
            for (int j = 0; j < usP1Holes; j++)
            {
                Debug.Assert(IntPointsTemp.Count == 0);

                IntPoints1AllHoles.Add(new C2DPointSet());
                Indexes1AllHoles.Add(new List <int>());

                if (Poly2.Rim.BoundingRect.Overlaps(Poly1.GetHole(j).BoundingRect))
                {
                    Poly2.Rim.Lines.GetIntersections(Poly1.GetHole(j).Lines,
                                                     IntPointsTemp, IndexesRim2, Indexes1AllHoles[j],
                                                     Poly2.Rim.BoundingRect, Poly1.GetHole(j).BoundingRect);

                    IntPointsRim2.AddCopy(IntPointsTemp);
                    IntPoints1AllHoles[j].ExtractAllOf(IntPointsTemp);
                }
            }

            // *** Quick Escape
            bool bRim1StartInPoly2 = Poly2.Contains(Poly1.Rim.Lines[0].GetPointFrom());
            bool bRim2StartInPoly1 = Poly1.Contains(Poly2.Rim.Lines[0].GetPointFrom());

            if (IntPointsRim1.Count != 0 || IntPointsRim2.Count != 0 ||
                bRim1StartInPoly2 || bRim2StartInPoly1)
            // pos no interaction
            {
                // *** Rim Routes
                Poly1.Rim.GetRoutes(IntPointsRim1, IndexesRim1, Routes1,
                                    bRim1StartInPoly2, bP1RoutesInside);
                Poly2.Rim.GetRoutes(IntPointsRim2, IndexesRim2, Routes2,
                                    bRim2StartInPoly1, bP2RoutesInside);

                if (IntPointsRim1.Count % 2 != 0)               // Must be even
                {
                    grid.LogDegenerateError();
                    //  Debug.Assert(false);
                }

                if (IntPointsRim2.Count % 2 != 0)               // Must be even
                {
                    grid.LogDegenerateError();
                    //   Debug.Assert(false);
                }

                // *** Hole Hole Intersections
                for (int h = 0; h < usP1Holes; h++)
                {
                    for (int k = 0; k < usP2Holes; k++)
                    {
                        Debug.Assert(IntPointsTemp.Count == 0);
                        C2DPolyBase pHole1 = Poly1.GetHole(h);
                        C2DPolyBase pHole2 = Poly2.GetHole(k);

                        if (pHole1.BoundingRect.Overlaps(pHole2.BoundingRect))
                        {
                            pHole1.Lines.GetIntersections(pHole2.Lines,
                                                          IntPointsTemp, Indexes1AllHoles[h], Indexes2AllHoles[k],
                                                          pHole1.BoundingRect, pHole2.BoundingRect);

                            IntPoints1AllHoles[h].AddCopy(IntPointsTemp);
                            IntPoints2AllHoles[k].ExtractAllOf(IntPointsTemp);
                        }
                    }
                }


                // *** Hole Routes
                for (int a = 0; a < usP1Holes; a++)
                {
                    C2DPolyBase pHole = Poly1.GetHole(a);

                    if (IntPoints1AllHoles[a].Count % 2 != 0)                   // Must be even
                    {
                        grid.LogDegenerateError();
                        //   Debug.Assert(false);
                    }

                    if (pHole.Lines.Count != 0)
                    {
                        bool bHole1StartInside = Poly2.Contains(pHole.Lines[0].GetPointFrom());
                        if (IntPoints1AllHoles[a].Count == 0)
                        {
                            if (bHole1StartInside == bP1RoutesInside)
                            {
                                CompleteHoles1.Add(new C2DPolyBase(pHole));
                            }
                        }
                        else
                        {
                            pHole.GetRoutes(IntPoints1AllHoles[a], Indexes1AllHoles[a], Routes1,
                                            bHole1StartInside, bP1RoutesInside);
                        }
                    }
                }
                // *** Hole Routes
                for (int b = 0; b < usP2Holes; b++)
                {
                    C2DPolyBase pHole = Poly2.GetHole(b);

                    if (IntPoints2AllHoles[b].Count % 2 != 0)                   // Must be even
                    {
                        grid.LogDegenerateError();
                        //    Debug.Assert(false);
                    }

                    if (pHole.Lines.Count != 0)
                    {
                        bool bHole2StartInside = Poly1.Contains(pHole.Lines[0].GetPointFrom());
                        if (IntPoints2AllHoles[b].Count == 0)
                        {
                            if (bHole2StartInside == bP2RoutesInside)
                            {
                                CompleteHoles2.Add(new C2DPolyBase(pHole));
                            }
                        }
                        else
                        {
                            pHole.GetRoutes(IntPoints2AllHoles[b], Indexes2AllHoles[b], Routes2,
                                            bHole2StartInside, bP2RoutesInside);
                        }
                    }
                }
            }


            //for (unsigned int i = 0 ; i < IntPoints1AllHoles.size(); i++)
            //    delete IntPoints1AllHoles[i];
            //for (unsigned int i = 0 ; i < IntPoints2AllHoles.size(); i++)
            //    delete IntPoints2AllHoles[i];
            //for (unsigned int i = 0 ; i < Indexes1AllHoles.size(); i++)
            //    delete Indexes1AllHoles[i];
            //for (unsigned int i = 0 ; i < Indexes2AllHoles.size(); i++)
            //    delete Indexes2AllHoles[i];
        }