//constructor
public Clipper(int InitOptions = 0)
: base()
{
m_Scanbeam = null;
m_Maxima = null;
m_ActiveEdges = null;
m_SortedEdges = null;
m_IntersectList = new List<IntersectNode>();
m_IntersectNodeComparer = new MyIntersectNodeSort();
m_ExecuteLocked = false;
m_UsingPolyTree = false;
m_PolyOuts = new List<OutRec>();
m_Joins = new List<Join>();
m_GhostJoins = new List<Join>();
ReverseSolution = (ioReverseSolution & InitOptions) != 0;
StrictlySimple = (ioStrictlySimple & InitOptions) != 0;
PreserveCollinear = (ioPreserveCollinear & InitOptions) != 0;
#if use_xyz
ZFillFunction = null;
#endif
}
//------------------------------------------------------------------------------
private void ProcessEdgesAtTopOfScanbeam(int topY)
{
TEdge e = m_ActiveEdges;
while (e != null)
{
//1. process maxima, treating them as if they're 'bent' horizontal edges,
// but exclude maxima with horizontal edges. nb: e can't be a horizontal.
bool IsMaximaEdge = IsMaxima(e, topY);
if (IsMaximaEdge)
{
TEdge eMaxPair = GetMaximaPairEx(e);
IsMaximaEdge = (eMaxPair == null || !IsHorizontal(eMaxPair));
}
if (IsMaximaEdge)
{
if (StrictlySimple) InsertMaxima(e.Top.X);
TEdge ePrev = e.PrevInAEL;
DoMaxima(e);
if (ePrev == null) e = m_ActiveEdges;
else e = ePrev.NextInAEL;
}
else
{
//2. promote horizontal edges, otherwise update Curr.X and Curr.Y ...
if (IsIntermediate(e, topY) && IsHorizontal(e.NextInLML))
{
UpdateEdgeIntoAEL(ref e);
if (e.OutIdx >= 0)
AddOutPt(e, e.Bot);
AddEdgeToSEL(e);
}
else
{
e.Curr.X = TopX(e, topY);
e.Curr.Y = topY;
}
//When StrictlySimple and 'e' is being touched by another edge, then
//make sure both edges have a vertex here ...
if (StrictlySimple)
{
TEdge ePrev = e.PrevInAEL;
if ((e.OutIdx >= 0) && (e.WindDelta != 0) && ePrev != null &&
(ePrev.OutIdx >= 0) && (ePrev.Curr.X == e.Curr.X) &&
(ePrev.WindDelta != 0))
{
IntPoint ip = new IntPoint(e.Curr);
#if use_xyz
SetZ(ref ip, ePrev, e);
#endif
OutPt op = AddOutPt(ePrev, ip);
OutPt op2 = AddOutPt(e, ip);
AddJoin(op, op2, ip); //StrictlySimple (type-3) join
}
}
e = e.NextInAEL;
}
}
//3. Process horizontals at the Top of the scanbeam ...
ProcessHorizontals();
m_Maxima = null;
//4. Promote intermediate vertices ...
e = m_ActiveEdges;
while (e != null)
{
if (IsIntermediate(e, topY))
{
OutPt op = null;
if (e.OutIdx >= 0)
op = AddOutPt(e, e.Top);
UpdateEdgeIntoAEL(ref e);
//if output polygons share an edge, they'll need joining later ...
TEdge ePrev = e.PrevInAEL;
TEdge eNext = e.NextInAEL;
if (ePrev != null && ePrev.Curr.X == e.Bot.X &&
ePrev.Curr.Y == e.Bot.Y && op != null &&
ePrev.OutIdx >= 0 && ePrev.Curr.Y > ePrev.Top.Y &&
SlopesEqual(e.Curr, e.Top, ePrev.Curr, ePrev.Top, m_UseFullRange) &&
(e.WindDelta != 0) && (ePrev.WindDelta != 0))
{
OutPt op2 = AddOutPt(ePrev, e.Bot);
AddJoin(op, op2, e.Top);
}
else if (eNext != null && eNext.Curr.X == e.Bot.X &&
eNext.Curr.Y == e.Bot.Y && op != null &&
eNext.OutIdx >= 0 && eNext.Curr.Y > eNext.Top.Y &&
SlopesEqual(e.Curr, e.Top, eNext.Curr, eNext.Top, m_UseFullRange) &&
(e.WindDelta != 0) && (eNext.WindDelta != 0))
{
OutPt op2 = AddOutPt(eNext, e.Bot);
AddJoin(op, op2, e.Top);
}
}
e = e.NextInAEL;
}
}
//------------------------------------------------------------------------------
private bool ExecuteInternal()
{
try
{
Reset();
m_SortedEdges = null;
m_Maxima = null;
int botY, topY;
if (!PopScanbeam(out botY)) return false;
InsertLocalMinimaIntoAEL(botY);
while (PopScanbeam(out topY) || LocalMinimaPending())
{
ProcessHorizontals();
m_GhostJoins.Clear();
if (!ProcessIntersections(topY)) return false;
ProcessEdgesAtTopOfScanbeam(topY);
botY = topY;
InsertLocalMinimaIntoAEL(botY);
}
//fix orientations ...
foreach (OutRec outRec in m_PolyOuts)
{
if (outRec.Pts == null || outRec.IsOpen) continue;
if ((outRec.IsHole ^ ReverseSolution) == (Area(outRec) > 0))
ReversePolyPtLinks(outRec.Pts);
}
JoinCommonEdges();
foreach (OutRec outRec in m_PolyOuts)
{
if (outRec.Pts == null)
continue;
else if (outRec.IsOpen)
FixupOutPolyline(outRec);
else
FixupOutPolygon(outRec);
}
if (StrictlySimple) DoSimplePolygons();
return true;
}
//catch { return false; }
finally
{
m_Joins.Clear();
m_GhostJoins.Clear();
}
}
//------------------------------------------------------------------------------
private void InsertMaxima(int X)
{
//double-linked list: sorted ascending, ignoring dups.
Maxima newMax = new Maxima();
newMax.X = X;
if (m_Maxima == null)
{
m_Maxima = newMax;
m_Maxima.Next = null;
m_Maxima.Prev = null;
}
else if (X < m_Maxima.X)
{
newMax.Next = m_Maxima;
newMax.Prev = null;
m_Maxima = newMax;
}
else
{
Maxima m = m_Maxima;
while (m.Next != null && (X >= m.Next.X)) m = m.Next;
if (X == m.X) return; //ie ignores duplicates (& CG to clean up newMax)
//insert newMax between m and m.Next ...
newMax.Next = m.Next;
newMax.Prev = m;
if (m.Next != null) m.Next.Prev = newMax;
m.Next = newMax;
}
}
/// <summary>
/// Reset all fields to default values in preparation for object recycling
/// </summary>
public void PrepareForRecycle()
{
X = new cInt();
Next = Prev = null;
}