//------------------------------------------------------------------------------
private void AddLocalMaxPoly(TEdge e1, TEdge e2, IntPoint pt)
{
AddOutPt(e1, pt);
if (e1.outIdx == e2.outIdx)
{
e1.outIdx = -1;
e2.outIdx = -1;
}
else if (e1.outIdx < e2.outIdx)
AppendPolygon(e1, e2);
else
AppendPolygon(e2, e1);
}
//------------------------------------------------------------------------------
private void InitEdge(TEdge e, TEdge eNext,
TEdge ePrev, IntPoint pt, PolyType polyType)
{
e.next = eNext;
e.prev = ePrev;
e.xcurr = pt.X;
e.ycurr = pt.Y;
if (e.ycurr >= e.next.ycurr)
{
e.xbot = e.xcurr;
e.ybot = e.ycurr;
e.xtop = e.next.xcurr;
e.ytop = e.next.ycurr;
e.windDelta = 1;
}
else
{
e.xtop = e.xcurr;
e.ytop = e.ycurr;
e.xbot = e.next.xcurr;
e.ybot = e.next.ycurr;
e.windDelta = -1;
}
SetDx(e);
e.polyType = polyType;
e.outIdx = -1;
}
//---------------------------------------------------------------------------
TEdge AddBoundsToLML(TEdge e)
{
//Starting at the top of one bound we progress to the bottom where there's
//a local minima. We then go to the top of the next bound. These two bounds
//form the left and right (or right and left) bounds of the local minima.
e.nextInLML = null;
e = e.next;
for (; ; )
{
if (e.dx == horizontal)
{
//nb: proceed through horizontals when approaching from their right,
// but break on horizontal minima if approaching from their left.
// This ensures 'local minima' are always on the left of horizontals.
if (e.next.ytop < e.ytop && e.next.xbot > e.prev.xbot) break;
if (e.xtop != e.prev.xbot) SwapX(e);
e.nextInLML = e.prev;
}
else if (e.ycurr == e.prev.ycurr) break;
else e.nextInLML = e.prev;
e = e.next;
}
//e and e.prev are now at a local minima ...
LocalMinima newLm = new LocalMinima();
newLm.next = null;
newLm.Y = e.prev.ybot;
if (e.dx == horizontal) //horizontal edges never start a left bound
{
if (e.xbot != e.prev.xbot) SwapX(e);
newLm.leftBound = e.prev;
newLm.rightBound = e;
}
else if (e.dx < e.prev.dx)
{
newLm.leftBound = e.prev;
newLm.rightBound = e;
}
else
{
newLm.leftBound = e;
newLm.rightBound = e.prev;
}
newLm.leftBound.side = EdgeSide.esLeft;
newLm.rightBound.side = EdgeSide.esRight;
InsertLocalMinima(newLm);
for (; ; )
{
if (e.next.ytop == e.ytop && e.next.dx != horizontal) break;
e.nextInLML = e.next;
e = e.next;
if (e.dx == horizontal && e.xbot != e.prev.xtop) SwapX(e);
}
return e.next;
}
//------------------------------------------------------------------------------
private void InsertIntersectNode(TEdge e1, TEdge e2, IntPoint pt)
{
IntersectNode newNode = new IntersectNode();
newNode.edge1 = e1;
newNode.edge2 = e2;
newNode.pt = pt;
newNode.next = null;
if (m_IntersectNodes == null) m_IntersectNodes = newNode;
else if (newNode.pt.Y > m_IntersectNodes.pt.Y)
{
newNode.next = m_IntersectNodes;
m_IntersectNodes = newNode;
}
else
{
IntersectNode iNode = m_IntersectNodes;
while (iNode.next != null && newNode.pt.Y < iNode.next.pt.Y)
iNode = iNode.next;
newNode.next = iNode.next;
iNode.next = newNode;
}
}
//------------------------------------------------------------------------------
private void DoMaxima(TEdge e, Int64 topY)
{
TEdge eMaxPair = GetMaximaPair(e);
Int64 X = e.xtop;
TEdge eNext = e.nextInAEL;
while (eNext != eMaxPair)
{
if (eNext == null) throw new ClipperException("DoMaxima error");
IntersectEdges(e, eNext, new IntPoint(X, topY), Protects.ipBoth);
SwapPositionsInAEL(e, eNext);
eNext = e.nextInAEL;
}
if (e.outIdx < 0 && eMaxPair.outIdx < 0)
{
DeleteFromAEL(e);
DeleteFromAEL(eMaxPair);
}
else if (e.outIdx >= 0 && eMaxPair.outIdx >= 0)
{
IntersectEdges(e, eMaxPair, new IntPoint(X, topY), Protects.ipNone);
}
else throw new ClipperException("DoMaxima error");
}
//------------------------------------------------------------------------------
private TEdge GetMaximaPair(TEdge e)
{
if (!IsMaxima(e.next, e.ytop) || (e.next.xtop != e.xtop))
return e.prev;
else
return e.next;
}
//------------------------------------------------------------------------------
private void BuildIntersectList(Int64 botY, Int64 topY)
{
if (m_ActiveEdges == null) return;
//prepare for sorting ...
TEdge e = m_ActiveEdges;
m_SortedEdges = e;
while (e != null)
{
e.prevInSEL = e.prevInAEL;
e.nextInSEL = e.nextInAEL;
e.xcurr = TopX(e, topY);
e = e.nextInAEL;
}
//bubblesort ...
bool isModified = true;
while (isModified && m_SortedEdges != null)
{
isModified = false;
e = m_SortedEdges;
while (e.nextInSEL != null)
{
TEdge eNext = e.nextInSEL;
IntPoint pt = new IntPoint();
if (e.xcurr > eNext.xcurr)
{
if (!IntersectPoint(e, eNext, ref pt) && e.xcurr > eNext.xcurr + 1)
throw new ClipperException("Intersection error");
if (pt.Y > botY)
{
pt.Y = botY;
pt.X = TopX(e, pt.Y);
}
InsertIntersectNode(e, eNext, pt);
SwapPositionsInSEL(e, eNext);
isModified = true;
}
else
e = eNext;
}
if (e.prevInSEL != null) e.prevInSEL.nextInSEL = null;
else break;
}
m_SortedEdges = null;
}
//------------------------------------------------------------------------------
private static void SwapPolyIndexes(TEdge edge1, TEdge edge2)
{
int outIdx = edge1.outIdx;
edge1.outIdx = edge2.outIdx;
edge2.outIdx = outIdx;
}
//------------------------------------------------------------------------------
private void IntersectEdges(TEdge e1, TEdge e2, IntPoint pt, Protects protects)
{
//e1 will be to the left of e2 BELOW the intersection. Therefore e1 is before
//e2 in AEL except when e1 is being inserted at the intersection point ...
bool e1stops = (Protects.ipLeft & protects) == 0 && e1.nextInLML == null &&
e1.xtop == pt.X && e1.ytop == pt.Y;
bool e2stops = (Protects.ipRight & protects) == 0 && e2.nextInLML == null &&
e2.xtop == pt.X && e2.ytop == pt.Y;
bool e1Contributing = (e1.outIdx >= 0);
bool e2contributing = (e2.outIdx >= 0);
//update winding counts...
//assumes that e1 will be to the right of e2 ABOVE the intersection
if (e1.polyType == e2.polyType)
{
if (IsEvenOddFillType(e1))
{
int oldE1WindCnt = e1.windCnt;
e1.windCnt = e2.windCnt;
e2.windCnt = oldE1WindCnt;
}
else
{
if (e1.windCnt + e2.windDelta == 0) e1.windCnt = -e1.windCnt;
else e1.windCnt += e2.windDelta;
if (e2.windCnt - e1.windDelta == 0) e2.windCnt = -e2.windCnt;
else e2.windCnt -= e1.windDelta;
}
}
else
{
if (!IsEvenOddFillType(e2)) e1.windCnt2 += e2.windDelta;
else e1.windCnt2 = (e1.windCnt2 == 0) ? 1 : 0;
if (!IsEvenOddFillType(e1)) e2.windCnt2 -= e1.windDelta;
else e2.windCnt2 = (e2.windCnt2 == 0) ? 1 : 0;
}
PolyFillType e1FillType, e2FillType, e1FillType2, e2FillType2;
if (e1.polyType == PolyType.ptSubject)
{
e1FillType = m_SubjFillType;
e1FillType2 = m_ClipFillType;
}
else
{
e1FillType = m_ClipFillType;
e1FillType2 = m_SubjFillType;
}
if (e2.polyType == PolyType.ptSubject)
{
e2FillType = m_SubjFillType;
e2FillType2 = m_ClipFillType;
}
else
{
e2FillType = m_ClipFillType;
e2FillType2 = m_SubjFillType;
}
int e1Wc, e2Wc;
switch (e1FillType)
{
case PolyFillType.pftPositive: e1Wc = e1.windCnt; break;
case PolyFillType.pftNegative: e1Wc = -e1.windCnt; break;
default: e1Wc = Math.Abs(e1.windCnt); break;
}
switch (e2FillType)
{
case PolyFillType.pftPositive: e2Wc = e2.windCnt; break;
case PolyFillType.pftNegative: e2Wc = -e2.windCnt; break;
default: e2Wc = Math.Abs(e2.windCnt); break;
}
if (e1Contributing && e2contributing)
{
if (e1stops || e2stops ||
(e1Wc != 0 && e1Wc != 1) || (e2Wc != 0 && e2Wc != 1) ||
(e1.polyType != e2.polyType && m_ClipType != ClipType.ctXor))
AddLocalMaxPoly(e1, e2, pt);
else
{
AddOutPt(e1, pt);
AddOutPt(e2, pt);
SwapSides(e1, e2);
SwapPolyIndexes(e1, e2);
}
}
else if (e1Contributing)
{
if (e2Wc == 0 || e2Wc == 1)
{
AddOutPt(e1, pt);
SwapSides(e1, e2);
SwapPolyIndexes(e1, e2);
}
}
else if (e2contributing)
{
if (e1Wc == 0 || e1Wc == 1)
{
AddOutPt(e2, pt);
SwapSides(e1, e2);
SwapPolyIndexes(e1, e2);
}
}
else if ((e1Wc == 0 || e1Wc == 1) &&
(e2Wc == 0 || e2Wc == 1) && !e1stops && !e2stops)
{
//neither edge is currently contributing ...
Int64 e1Wc2, e2Wc2;
switch (e1FillType2)
{
case PolyFillType.pftPositive: e1Wc2 = e1.windCnt2; break;
case PolyFillType.pftNegative: e1Wc2 = -e1.windCnt2; break;
default: e1Wc2 = Math.Abs(e1.windCnt2); break;
}
switch (e2FillType2)
{
case PolyFillType.pftPositive: e2Wc2 = e2.windCnt2; break;
case PolyFillType.pftNegative: e2Wc2 = -e2.windCnt2; break;
default: e2Wc2 = Math.Abs(e2.windCnt2); break;
}
if (e1.polyType != e2.polyType)
AddLocalMinPoly(e1, e2, pt);
else if (e1Wc == 1 && e2Wc == 1)
switch (m_ClipType)
{
case ClipType.ctIntersection:
if (e1Wc2 > 0 && e2Wc2 > 0)
AddLocalMinPoly(e1, e2, pt);
break;
case ClipType.ctUnion:
if (e1Wc2 <= 0 && e2Wc2 <= 0)
AddLocalMinPoly(e1, e2, pt);
break;
case ClipType.ctDifference:
if (((e1.polyType == PolyType.ptClip) && (e1Wc2 > 0) && (e2Wc2 > 0)) ||
((e1.polyType == PolyType.ptSubject) && (e1Wc2 <= 0) && (e2Wc2 <= 0)))
AddLocalMinPoly(e1, e2, pt);
break;
case ClipType.ctXor:
AddLocalMinPoly(e1, e2, pt);
break;
}
else
SwapSides(e1, e2);
}
if ((e1stops != e2stops) &&
((e1stops && (e1.outIdx >= 0)) || (e2stops && (e2.outIdx >= 0))))
{
SwapSides(e1, e2);
SwapPolyIndexes(e1, e2);
}
//finally, delete any non-contributing maxima edges ...
if (e1stops) DeleteFromAEL(e1);
if (e2stops) DeleteFromAEL(e2);
}
//------------------------------------------------------------------------------
private void AppendPolygon(TEdge e1, TEdge e2)
{
//get the start and ends of both output polygons ...
OutRec outRec1 = m_PolyOuts[e1.outIdx];
OutRec outRec2 = m_PolyOuts[e2.outIdx];
OutRec holeStateRec;
if (Param1RightOfParam2(outRec1, outRec2))
holeStateRec = outRec2;
else if (Param1RightOfParam2(outRec2, outRec1))
holeStateRec = outRec1;
else
holeStateRec = GetLowermostRec(outRec1, outRec2);
OutPt p1_lft = outRec1.pts;
OutPt p1_rt = p1_lft.prev;
OutPt p2_lft = outRec2.pts;
OutPt p2_rt = p2_lft.prev;
EdgeSide side;
//join e2 poly onto e1 poly and delete pointers to e2 ...
if (e1.side == EdgeSide.esLeft)
{
if (e2.side == EdgeSide.esLeft)
{
//z y x a b c
ReversePolyPtLinks(p2_lft);
p2_lft.next = p1_lft;
p1_lft.prev = p2_lft;
p1_rt.next = p2_rt;
p2_rt.prev = p1_rt;
outRec1.pts = p2_rt;
}
else
{
//x y z a b c
p2_rt.next = p1_lft;
p1_lft.prev = p2_rt;
p2_lft.prev = p1_rt;
p1_rt.next = p2_lft;
outRec1.pts = p2_lft;
}
side = EdgeSide.esLeft;
}
else
{
if (e2.side == EdgeSide.esRight)
{
//a b c z y x
ReversePolyPtLinks(p2_lft);
p1_rt.next = p2_rt;
p2_rt.prev = p1_rt;
p2_lft.next = p1_lft;
p1_lft.prev = p2_lft;
}
else
{
//a b c x y z
p1_rt.next = p2_lft;
p2_lft.prev = p1_rt;
p1_lft.prev = p2_rt;
p2_rt.next = p1_lft;
}
side = EdgeSide.esRight;
}
outRec1.bottomPt = null;
if (holeStateRec == outRec2)
{
if (outRec2.FirstLeft != outRec1)
outRec1.FirstLeft = outRec2.FirstLeft;
outRec1.isHole = outRec2.isHole;
}
outRec2.pts = null;
outRec2.bottomPt = null;
outRec2.FirstLeft = outRec1;
int OKIdx = e1.outIdx;
int ObsoleteIdx = e2.outIdx;
e1.outIdx = -1; //nb: safe because we only get here via AddLocalMaxPoly
e2.outIdx = -1;
TEdge e = m_ActiveEdges;
while (e != null)
{
if (e.outIdx == ObsoleteIdx)
{
e.outIdx = OKIdx;
e.side = side;
break;
}
e = e.nextInAEL;
}
outRec2.idx = outRec1.idx;
}
//------------------------------------------------------------------------------
private static void SwapSides(TEdge edge1, TEdge edge2)
{
EdgeSide side = edge1.side;
edge1.side = edge2.side;
edge2.side = side;
}
//------------------------------------------------------------------------------
private void SetHoleState(TEdge e, OutRec outRec)
{
bool isHole = false;
TEdge e2 = e.prevInAEL;
while (e2 != null)
{
if (e2.outIdx >= 0)
{
isHole = !isHole;
if (outRec.FirstLeft == null)
outRec.FirstLeft = m_PolyOuts[e2.outIdx];
}
e2 = e2.prevInAEL;
}
if (isHole) outRec.isHole = true;
}
//------------------------------------------------------------------------------
private void AddOutPt(TEdge e, IntPoint pt)
{
bool ToFront = (e.side == EdgeSide.esLeft);
if (e.outIdx < 0)
{
OutRec outRec = CreateOutRec();
e.outIdx = outRec.idx;
OutPt op = new OutPt();
outRec.pts = op;
op.pt = pt;
op.idx = outRec.idx;
op.next = op;
op.prev = op;
SetHoleState(e, outRec);
}
else
{
OutRec outRec = m_PolyOuts[e.outIdx];
OutPt op = outRec.pts, op2;
if (ToFront && PointsEqual(pt, op.pt) ||
(!ToFront && PointsEqual(pt, op.prev.pt))) return;
op2 = new OutPt();
op2.pt = pt;
op2.idx = outRec.idx;
op2.next = op;
op2.prev = op.prev;
op2.prev.next = op2;
op.prev = op2;
if (ToFront) outRec.pts = op2;
}
}
//------------------------------------------------------------------------------
private void AddLocalMinPoly(TEdge e1, TEdge e2, IntPoint pt)
{
TEdge e, prevE;
if (e2.dx == horizontal || (e1.dx > e2.dx))
{
AddOutPt(e1, pt);
e2.outIdx = e1.outIdx;
e1.side = EdgeSide.esLeft;
e2.side = EdgeSide.esRight;
e = e1;
if (e.prevInAEL == e2)
prevE = e2.prevInAEL;
else
prevE = e.prevInAEL;
}
else
{
AddOutPt(e2, pt);
e1.outIdx = e2.outIdx;
e1.side = EdgeSide.esRight;
e2.side = EdgeSide.esLeft;
e = e2;
if (e.prevInAEL == e1)
prevE = e1.prevInAEL;
else
prevE = e.prevInAEL;
}
if (prevE != null && prevE.outIdx >= 0 &&
(TopX(prevE, pt.Y) == TopX(e, pt.Y)) &&
SlopesEqual(e, prevE, m_UseFullRange))
AddJoin(e, prevE, -1, -1);
}
//------------------------------------------------------------------------------
private bool IsMaxima(TEdge e, double Y)
{
return (e != null && e.ytop == Y && e.nextInLML == null);
}
//------------------------------------------------------------------------------
private void DeleteFromAEL(TEdge e)
{
TEdge AelPrev = e.prevInAEL;
TEdge AelNext = e.nextInAEL;
if (AelPrev == null && AelNext == null && (e != m_ActiveEdges))
return; //already deleted
if (AelPrev != null)
AelPrev.nextInAEL = AelNext;
else m_ActiveEdges = AelNext;
if (AelNext != null)
AelNext.prevInAEL = AelPrev;
e.nextInAEL = null;
e.prevInAEL = null;
}
//------------------------------------------------------------------------------
private bool IsIntermediate(TEdge e, double Y)
{
return (e.ytop == Y && e.nextInLML != null);
}
//------------------------------------------------------------------------------
private void DeleteFromSEL(TEdge e)
{
TEdge SelPrev = e.prevInSEL;
TEdge SelNext = e.nextInSEL;
if (SelPrev == null && SelNext == null && (e != m_SortedEdges))
return; //already deleted
if (SelPrev != null)
SelPrev.nextInSEL = SelNext;
else m_SortedEdges = SelNext;
if (SelNext != null)
SelNext.prevInSEL = SelPrev;
e.nextInSEL = null;
e.prevInSEL = null;
}
//------------------------------------------------------------------------------
private bool ProcessIntersections(Int64 botY, Int64 topY)
{
if (m_ActiveEdges == null) return true;
try
{
BuildIntersectList(botY, topY);
if (m_IntersectNodes == null) return true;
if (m_IntersectNodes.next == null || FixupIntersectionOrder())
ProcessIntersectList();
else
return false;
}
catch
{
m_SortedEdges = null;
DisposeIntersectNodes();
throw new ClipperException("ProcessIntersections error");
}
m_SortedEdges = null;
return true;
}
//------------------------------------------------------------------------------
private void UpdateEdgeIntoAEL(ref TEdge e)
{
if (e.nextInLML == null)
throw new ClipperException("UpdateEdgeIntoAEL: invalid call");
TEdge AelPrev = e.prevInAEL;
TEdge AelNext = e.nextInAEL;
e.nextInLML.outIdx = e.outIdx;
if (AelPrev != null)
AelPrev.nextInAEL = e.nextInLML;
else m_ActiveEdges = e.nextInLML;
if (AelNext != null)
AelNext.prevInAEL = e.nextInLML;
e.nextInLML.side = e.side;
e.nextInLML.windDelta = e.windDelta;
e.nextInLML.windCnt = e.windCnt;
e.nextInLML.windCnt2 = e.windCnt2;
e = e.nextInLML;
e.prevInAEL = AelPrev;
e.nextInAEL = AelNext;
if (e.dx != horizontal) InsertScanbeam(e.ytop);
}
//------------------------------------------------------------------------------
private static Int64 TopX(TEdge edge, Int64 currentY)
{
if (currentY == edge.ytop)
return edge.xtop;
return edge.xbot + Round(edge.dx * (currentY - edge.ybot));
}
//------------------------------------------------------------------------------
private void ProcessHorizontal(TEdge horzEdge)
{
Direction Direction;
Int64 horzLeft, horzRight;
if (horzEdge.xcurr < horzEdge.xtop)
{
horzLeft = horzEdge.xcurr;
horzRight = horzEdge.xtop;
Direction = Direction.dLeftToRight;
}
else
{
horzLeft = horzEdge.xtop;
horzRight = horzEdge.xcurr;
Direction = Direction.dRightToLeft;
}
TEdge eMaxPair;
if (horzEdge.nextInLML != null)
eMaxPair = null;
else
eMaxPair = GetMaximaPair(horzEdge);
TEdge e = GetNextInAEL(horzEdge, Direction);
while (e != null)
{
if (e.xcurr == horzEdge.xtop && eMaxPair == null)
{
if (SlopesEqual(e, horzEdge.nextInLML, m_UseFullRange))
{
//if output polygons share an edge, they'll need joining later ...
if (horzEdge.outIdx >= 0 && e.outIdx >= 0)
AddJoin(horzEdge.nextInLML, e, horzEdge.outIdx, -1);
break; //we've reached the end of the horizontal line
}
else if (e.dx < horzEdge.nextInLML.dx)
//we really have got to the end of the intermediate horz edge so quit.
//nb: More -ve slopes follow more +ve slopes ABOVE the horizontal.
break;
}
TEdge eNext = GetNextInAEL(e, Direction);
if (eMaxPair != null ||
((Direction == Direction.dLeftToRight) && (e.xcurr < horzRight)) ||
((Direction == Direction.dRightToLeft) && (e.xcurr > horzLeft)))
{
//so far we're still in range of the horizontal edge
if (e == eMaxPair)
{
//horzEdge is evidently a maxima horizontal and we've arrived at its end.
if (Direction == Direction.dLeftToRight)
IntersectEdges(horzEdge, e, new IntPoint(e.xcurr, horzEdge.ycurr), 0);
else
IntersectEdges(e, horzEdge, new IntPoint(e.xcurr, horzEdge.ycurr), 0);
if (eMaxPair.outIdx >= 0) throw new ClipperException("ProcessHorizontal error");
return;
}
else if (e.dx == horizontal && !IsMinima(e) && !(e.xcurr > e.xtop))
{
if (Direction == Direction.dLeftToRight)
IntersectEdges(horzEdge, e, new IntPoint(e.xcurr, horzEdge.ycurr),
(IsTopHorz(horzEdge, e.xcurr)) ? Protects.ipLeft : Protects.ipBoth);
else
IntersectEdges(e, horzEdge, new IntPoint(e.xcurr, horzEdge.ycurr),
(IsTopHorz(horzEdge, e.xcurr)) ? Protects.ipRight : Protects.ipBoth);
}
else if (Direction == Direction.dLeftToRight)
{
IntersectEdges(horzEdge, e, new IntPoint(e.xcurr, horzEdge.ycurr),
(IsTopHorz(horzEdge, e.xcurr)) ? Protects.ipLeft : Protects.ipBoth);
}
else
{
IntersectEdges(e, horzEdge, new IntPoint(e.xcurr, horzEdge.ycurr),
(IsTopHorz(horzEdge, e.xcurr)) ? Protects.ipRight : Protects.ipBoth);
}
SwapPositionsInAEL(horzEdge, e);
}
else if ((Direction == Direction.dLeftToRight && e.xcurr >= horzRight) ||
(Direction == Direction.dRightToLeft && e.xcurr <= horzLeft)) break;
e = eNext;
} //end while ( e )
if (horzEdge.nextInLML != null)
{
if (horzEdge.outIdx >= 0)
AddOutPt(horzEdge, new IntPoint(horzEdge.xtop, horzEdge.ytop));
UpdateEdgeIntoAEL(ref horzEdge);
}
else
{
if (horzEdge.outIdx >= 0)
IntersectEdges(horzEdge, eMaxPair,
new IntPoint(horzEdge.xtop, horzEdge.ycurr), Protects.ipBoth);
DeleteFromAEL(eMaxPair);
DeleteFromAEL(horzEdge);
}
}
//------------------------------------------------------------------------------
private bool IntersectPoint(TEdge edge1, TEdge edge2, ref IntPoint ip)
{
double b1, b2;
if (SlopesEqual(edge1, edge2, m_UseFullRange))
{
if (edge2.ybot > edge1.ybot)
ip.Y = edge2.ybot;
else
ip.Y = edge1.ybot;
return false;
}
else if (edge1.dx == 0)
{
ip.X = edge1.xbot;
if (edge2.dx == horizontal)
{
ip.Y = edge2.ybot;
}
else
{
b2 = edge2.ybot - (edge2.xbot / edge2.dx);
ip.Y = Round(ip.X / edge2.dx + b2);
}
}
else if (edge2.dx == 0)
{
ip.X = edge2.xbot;
if (edge1.dx == horizontal)
{
ip.Y = edge1.ybot;
}
else
{
b1 = edge1.ybot - (edge1.xbot / edge1.dx);
ip.Y = Round(ip.X / edge1.dx + b1);
}
}
else
{
b1 = edge1.xbot - edge1.ybot * edge1.dx;
b2 = edge2.xbot - edge2.ybot * edge2.dx;
double q = (b2 - b1) / (edge1.dx - edge2.dx);
ip.Y = Round(q);
if (Math.Abs(edge1.dx) < Math.Abs(edge2.dx))
ip.X = Round(edge1.dx * q + b1);
else
ip.X = Round(edge2.dx * q + b2);
}
if (ip.Y < edge1.ytop || ip.Y < edge2.ytop)
{
if (edge1.ytop > edge2.ytop)
{
ip.X = edge1.xtop;
ip.Y = edge1.ytop;
return TopX(edge2, edge1.ytop) < edge1.xtop;
}
else
{
ip.X = edge2.xtop;
ip.Y = edge2.ytop;
return TopX(edge1, edge2.ytop) > edge2.xtop;
}
}
else
return true;
}
//------------------------------------------------------------------------------
private bool IsTopHorz(TEdge horzEdge, double XPos)
{
TEdge e = m_SortedEdges;
while (e != null)
{
if ((XPos >= Math.Min(e.xcurr, e.xtop)) && (XPos <= Math.Max(e.xcurr, e.xtop)))
return false;
e = e.nextInSEL;
}
return true;
}
//------------------------------------------------------------------------------
internal static bool SlopesEqual(TEdge e1, TEdge e2, bool UseFullRange)
{
if (UseFullRange)
return Int128.Int128Mul(e1.deltaY, e2.deltaX) ==
Int128.Int128Mul(e1.deltaX, e2.deltaY);
else return (Int64)(e1.deltaY) * (e2.deltaX) ==
(Int64)(e1.deltaX) * (e2.deltaY);
}
//------------------------------------------------------------------------------
private TEdge GetNextInAEL(TEdge e, Direction Direction)
{
return Direction == Direction.dLeftToRight ? e.nextInAEL : e.prevInAEL;
}
//------------------------------------------------------------------------------
private void SetDx(TEdge e)
{
e.deltaX = (e.xtop - e.xbot);
e.deltaY = (e.ytop - e.ybot);
if (e.deltaY == 0) e.dx = horizontal;
else e.dx = (double)(e.deltaX) / (e.deltaY);
}
//------------------------------------------------------------------------------
private bool IsMinima(TEdge e)
{
return e != null && (e.prev.nextInLML != e) && (e.next.nextInLML != e);
}
//------------------------------------------------------------------------------
private void SwapX(TEdge e)
{
//swap horizontal edges' top and bottom x's so they follow the natural
//progression of the bounds - ie so their xbots will align with the
//adjoining lower edge. [Helpful in the ProcessHorizontal() method.]
e.xcurr = e.xtop;
e.xtop = e.xbot;
e.xbot = e.xcurr;
}
//------------------------------------------------------------------------------
private void SwapPositionsInSEL(TEdge edge1, TEdge edge2)
{
if (edge1.nextInSEL == null && edge1.prevInSEL == null)
return;
if (edge2.nextInSEL == null && edge2.prevInSEL == null)
return;
if (edge1.nextInSEL == edge2)
{
TEdge next = edge2.nextInSEL;
if (next != null)
next.prevInSEL = edge1;
TEdge prev = edge1.prevInSEL;
if (prev != null)
prev.nextInSEL = edge2;
edge2.prevInSEL = prev;
edge2.nextInSEL = edge1;
edge1.prevInSEL = edge2;
edge1.nextInSEL = next;
}
else if (edge2.nextInSEL == edge1)
{
TEdge next = edge1.nextInSEL;
if (next != null)
next.prevInSEL = edge2;
TEdge prev = edge2.prevInSEL;
if (prev != null)
prev.nextInSEL = edge1;
edge1.prevInSEL = prev;
edge1.nextInSEL = edge2;
edge2.prevInSEL = edge1;
edge2.nextInSEL = next;
}
else
{
TEdge next = edge1.nextInSEL;
TEdge prev = edge1.prevInSEL;
edge1.nextInSEL = edge2.nextInSEL;
if (edge1.nextInSEL != null)
edge1.nextInSEL.prevInSEL = edge1;
edge1.prevInSEL = edge2.prevInSEL;
if (edge1.prevInSEL != null)
edge1.prevInSEL.nextInSEL = edge1;
edge2.nextInSEL = next;
if (edge2.nextInSEL != null)
edge2.nextInSEL.prevInSEL = edge2;
edge2.prevInSEL = prev;
if (edge2.prevInSEL != null)
edge2.prevInSEL.nextInSEL = edge2;
}
if (edge1.prevInSEL == null)
m_SortedEdges = edge1;
else if (edge2.prevInSEL == null)
m_SortedEdges = edge2;
}