//------------------------------------------------------------------------------
internal ClipperBase() //constructor (nb: no external instantiation)
{
m_MinimaList = null;
m_CurrentLM = null;
m_UseFullRange = false;
m_HasOpenPaths = false;
}
//------------------------------------------------------------------------------
internal virtual void Reset()
{
m_CurrentLM = m_MinimaList;
if (m_CurrentLM == null)
{
return; //ie nothing to process
}
//reset all edges ...
m_Scanbeam = null;
ClipperLocalMinima lm = m_MinimaList;
while (lm != null)
{
InsertScanbeam(lm.Y);
ClipperTEdge e = lm.LeftBound;
if (e != null)
{
e.Curr = e.Bot;
e.OutIdx = Unassigned;
}
e = lm.RightBound;
if (e != null)
{
e.Curr = e.Bot;
e.OutIdx = Unassigned;
}
lm = lm.Next;
}
m_ActiveEdges = null;
}
//------------------------------------------------------------------------------
internal bool PopLocalMinima(long Y, out ClipperLocalMinima current)
{
current = m_CurrentLM;
if (m_CurrentLM != null && m_CurrentLM.Y == Y)
{
m_CurrentLM = m_CurrentLM.Next;
return(true);
}
return(false);
}
//------------------------------------------------------------------------------
private void DisposeLocalMinimaList()
{
while (m_MinimaList != null)
{
ClipperLocalMinima tmpLm = m_MinimaList.Next;
m_MinimaList = null;
m_MinimaList = tmpLm;
}
m_CurrentLM = null;
}
//---------------------------------------------------------------------------
private void InsertLocalMinima(ClipperLocalMinima newLm)
{
if (m_MinimaList == null)
{
m_MinimaList = newLm;
}
else if (newLm.Y >= m_MinimaList.Y)
{
newLm.Next = m_MinimaList;
m_MinimaList = newLm;
}
else
{
ClipperLocalMinima tmpLm = m_MinimaList;
while (tmpLm.Next != null && (newLm.Y < tmpLm.Next.Y))
{
tmpLm = tmpLm.Next;
}
newLm.Next = tmpLm.Next;
tmpLm.Next = newLm;
}
}
//------------------------------------------------------------------------------
public bool AddPath(List <ClipperIntPoint> pg, ClipperPolyType polyType, bool Closed)
{
if (!Closed && polyType == ClipperPolyType.Clip)
{
throw new ClipperException("AddPath: Open paths must be subject.");
}
int highI = (int)pg.Count - 1;
if (Closed)
{
while (highI > 0 && (pg[highI] == pg[0]))
{
--highI;
}
}
while (highI > 0 && (pg[highI] == pg[highI - 1]))
{
--highI;
}
if ((Closed && highI < 2) || (!Closed && highI < 1))
{
return(false);
}
//create a new edge array ...
List <ClipperTEdge> edges = new List <ClipperTEdge>(highI + 1);
for (int i = 0; i <= highI; i++)
{
edges.Add(new ClipperTEdge());
}
bool IsFlat = true;
//1. Basic (first) edge initialization ...
edges[1].Curr = pg[1];
RangeTest(pg[0], ref m_UseFullRange);
RangeTest(pg[highI], ref m_UseFullRange);
InitEdge(edges[0], edges[1], edges[highI], pg[0]);
InitEdge(edges[highI], edges[0], edges[highI - 1], pg[highI]);
for (int i = highI - 1; i >= 1; --i)
{
RangeTest(pg[i], ref m_UseFullRange);
InitEdge(edges[i], edges[i + 1], edges[i - 1], pg[i]);
}
ClipperTEdge eStart = edges[0];
//2. Remove duplicate vertices, and (when closed) collinear edges ...
ClipperTEdge E = eStart, eLoopStop = eStart;
for (; ;)
{
//nb: allows matching start and end points when not Closed ...
if (E.Curr == E.Next.Curr && (Closed || E.Next != eStart))
{
if (E == E.Next)
{
break;
}
if (E == eStart)
{
eStart = E.Next;
}
E = RemoveEdge(E);
eLoopStop = E;
continue;
}
if (E.Prev == E.Next)
{
break; //only two vertices
}
else if (Closed &&
SlopesEqual(E.Prev.Curr, E.Curr, E.Next.Curr, m_UseFullRange) &&
(!PreserveCollinear ||
!Pt2IsBetweenPt1AndPt3(E.Prev.Curr, E.Curr, E.Next.Curr)))
{
//Collinear edges are allowed for open paths but in closed paths
//the default is to merge adjacent collinear edges into a single edge.
//However, if the PreserveCollinear property is enabled, only overlapping
//collinear edges (ie spikes) will be removed from closed paths.
if (E == eStart)
{
eStart = E.Next;
}
E = RemoveEdge(E);
E = E.Prev;
eLoopStop = E;
continue;
}
E = E.Next;
if ((E == eLoopStop) || (!Closed && E.Next == eStart))
{
break;
}
}
if ((!Closed && (E == E.Next)) || (Closed && (E.Prev == E.Next)))
{
return(false);
}
if (!Closed)
{
m_HasOpenPaths = true;
eStart.Prev.OutIdx = Skip;
}
//3. Do second stage of edge initialization ...
E = eStart;
do
{
InitEdge2(E, polyType);
E = E.Next;
if (IsFlat && E.Curr.Y != eStart.Curr.Y)
{
IsFlat = false;
}
}while (E != eStart);
//4. Finally, add edge bounds to LocalMinima list ...
//Totally flat paths must be handled differently when adding them
//to LocalMinima list to avoid endless loops etc ...
if (IsFlat)
{
if (Closed)
{
return(false);
}
E.Prev.OutIdx = Skip;
ClipperLocalMinima locMin = new ClipperLocalMinima
{
Next = null,
Y = E.Bot.Y,
LeftBound = null,
RightBound = E
};
locMin.RightBound.Side = ClipperEdgeSide.Right;
locMin.RightBound.WindDelta = 0;
for (; ;)
{
if (E.Bot.X != E.Prev.Top.X)
{
ReverseHorizontal(E);
}
if (E.Next.OutIdx == Skip)
{
break;
}
E.NextInLML = E.Next;
E = E.Next;
}
InsertLocalMinima(locMin);
m_edges.Add(edges);
return(true);
}
m_edges.Add(edges);
bool leftBoundIsForward;
ClipperTEdge EMin = null;
//workaround to avoid an endless loop in the while loop below when
//open paths have matching start and end points ...
if (E.Prev.Bot == E.Prev.Top)
{
E = E.Next;
}
for (; ;)
{
E = FindNextLocMin(E);
if (E == EMin)
{
break;
}
else if (EMin == null)
{
EMin = E;
}
//E and E.Prev now share a local minima (left aligned if horizontal).
//Compare their slopes to find which starts which bound ...
ClipperLocalMinima locMin = new ClipperLocalMinima
{
Next = null,
Y = E.Bot.Y
};
if (E.Dx < E.Prev.Dx)
{
locMin.LeftBound = E.Prev;
locMin.RightBound = E;
leftBoundIsForward = false; //Q.nextInLML = Q.prev
}
else
{
locMin.LeftBound = E;
locMin.RightBound = E.Prev;
leftBoundIsForward = true; //Q.nextInLML = Q.next
}
locMin.LeftBound.Side = ClipperEdgeSide.Left;
locMin.RightBound.Side = ClipperEdgeSide.Right;
if (!Closed)
{
locMin.LeftBound.WindDelta = 0;
}
else if (locMin.LeftBound.Next == locMin.RightBound)
{
locMin.LeftBound.WindDelta = -1;
}
else
{
locMin.LeftBound.WindDelta = 1;
}
locMin.RightBound.WindDelta = -locMin.LeftBound.WindDelta;
E = ProcessBound(locMin.LeftBound, leftBoundIsForward);
if (E.OutIdx == Skip)
{
E = ProcessBound(E, leftBoundIsForward);
}
ClipperTEdge E2 = ProcessBound(locMin.RightBound, !leftBoundIsForward);
if (E2.OutIdx == Skip)
{
E2 = ProcessBound(E2, !leftBoundIsForward);
}
if (locMin.LeftBound.OutIdx == Skip)
{
locMin.LeftBound = null;
}
else if (locMin.RightBound.OutIdx == Skip)
{
locMin.RightBound = null;
}
InsertLocalMinima(locMin);
if (!leftBoundIsForward)
{
E = E2;
}
}
return(true);
}
//------------------------------------------------------------------------------
private ClipperTEdge ProcessBound(ClipperTEdge E, bool LeftBoundIsForward)
{
ClipperTEdge EStart, Result = E;
ClipperTEdge Horz;
if (Result.OutIdx == Skip)
{
//check if there are edges beyond the skip edge in the bound and if so
//create another LocMin and calling ProcessBound once more ...
E = Result;
if (LeftBoundIsForward)
{
while (E.Top.Y == E.Next.Bot.Y)
{
E = E.Next;
}
while (E != Result && E.Dx == Horizontal)
{
E = E.Prev;
}
}
else
{
while (E.Top.Y == E.Prev.Bot.Y)
{
E = E.Prev;
}
while (E != Result && E.Dx == Horizontal)
{
E = E.Next;
}
}
if (E == Result)
{
if (LeftBoundIsForward)
{
Result = E.Next;
}
else
{
Result = E.Prev;
}
}
else
{
//there are more edges in the bound beyond result starting with E
if (LeftBoundIsForward)
{
E = Result.Next;
}
else
{
E = Result.Prev;
}
ClipperLocalMinima locMin = new ClipperLocalMinima
{
Next = null,
Y = E.Bot.Y,
LeftBound = null,
RightBound = E
};
E.WindDelta = 0;
Result = ProcessBound(E, LeftBoundIsForward);
InsertLocalMinima(locMin);
}
return(Result);
}
if (E.Dx == Horizontal)
{
//We need to be careful with open paths because this may not be a
//true local minima (ie E may be following a skip edge).
//Also, consecutive horz. edges may start heading left before going right.
if (LeftBoundIsForward)
{
EStart = E.Prev;
}
else
{
EStart = E.Next;
}
if (EStart.Dx == Horizontal) //ie an adjoining horizontal skip edge
{
if (EStart.Bot.X != E.Bot.X && EStart.Top.X != E.Bot.X)
{
ReverseHorizontal(E);
}
}
else if (EStart.Bot.X != E.Bot.X)
{
ReverseHorizontal(E);
}
}
EStart = E;
if (LeftBoundIsForward)
{
while (Result.Top.Y == Result.Next.Bot.Y && Result.Next.OutIdx != Skip)
{
Result = Result.Next;
}
if (Result.Dx == Horizontal && Result.Next.OutIdx != Skip)
{
//nb: at the top of a bound, horizontals are added to the bound
//only when the preceding edge attaches to the horizontal's left vertex
//unless a Skip edge is encountered when that becomes the top divide
Horz = Result;
while (Horz.Prev.Dx == Horizontal)
{
Horz = Horz.Prev;
}
if (Horz.Prev.Top.X > Result.Next.Top.X)
{
Result = Horz.Prev;
}
}
while (E != Result)
{
E.NextInLML = E.Next;
if (E.Dx == Horizontal && E != EStart && E.Bot.X != E.Prev.Top.X)
{
ReverseHorizontal(E);
}
E = E.Next;
}
if (E.Dx == Horizontal && E != EStart && E.Bot.X != E.Prev.Top.X)
{
ReverseHorizontal(E);
}
Result = Result.Next; //move to the edge just beyond current bound
}
else
{
while (Result.Top.Y == Result.Prev.Bot.Y && Result.Prev.OutIdx != Skip)
{
Result = Result.Prev;
}
if (Result.Dx == Horizontal && Result.Prev.OutIdx != Skip)
{
Horz = Result;
while (Horz.Next.Dx == Horizontal)
{
Horz = Horz.Next;
}
if (Horz.Next.Top.X == Result.Prev.Top.X ||
Horz.Next.Top.X > Result.Prev.Top.X)
{
Result = Horz.Next;
}
}
while (E != Result)
{
E.NextInLML = E.Prev;
if (E.Dx == Horizontal && E != EStart && E.Bot.X != E.Next.Top.X)
{
ReverseHorizontal(E);
}
E = E.Prev;
}
if (E.Dx == Horizontal && E != EStart && E.Bot.X != E.Next.Top.X)
{
ReverseHorizontal(E);
}
Result = Result.Prev; //move to the edge just beyond current bound
}
return(Result);
}
