//------------------------------------------------------------------------------
double Area(OutRec outRec)
{
OutPt op = outRec.Pts;
if (op == null) return 0;
double a = 0;
do {
a = a + (double)(op.Pt.X + op.Prev.Pt.X) * (double)(op.Prev.Pt.Y - op.Pt.Y);
op = op.Next;
} while (op != outRec.Pts);
return a/2;
}
//----------------------------------------------------------------------
private void FixupFirstLefts2(OutRec OldOutRec, OutRec NewOutRec)
{
foreach (OutRec outRec in m_PolyOuts)
if (outRec.FirstLeft == OldOutRec) outRec.FirstLeft = NewOutRec;
}
//------------------------------------------------------------------------------
private void UpdateOutPtIdxs(OutRec outrec)
{
OutPt op = outrec.Pts;
do
{
op.Idx = outrec.Idx;
op = op.Prev;
}
while(op != outrec.Pts);
}
//------------------------------------------------------------------------------
private void FixupOutPolygon(OutRec outRec)
{
//FixupOutPolygon() - removes duplicate points and simplifies consecutive
//parallel edges by removing the middle vertex.
OutPt lastOK = null;
outRec.BottomPt = null;
OutPt pp = outRec.Pts;
for (;;)
{
if (pp.Prev == pp || pp.Prev == pp.Next)
{
DisposeOutPts(pp);
outRec.Pts = null;
return;
}
//test for duplicate points and collinear edges ...
if ((pp.Pt == pp.Next.Pt) || (pp.Pt == pp.Prev.Pt) ||
(SlopesEqual(pp.Prev.Pt, pp.Pt, pp.Next.Pt, m_UseFullRange) &&
(!PreserveCollinear || !Pt2IsBetweenPt1AndPt3(pp.Prev.Pt, pp.Pt, pp.Next.Pt))))
{
lastOK = null;
pp.Prev.Next = pp.Next;
pp.Next.Prev = pp.Prev;
pp = pp.Prev;
}
else if (pp == lastOK) break;
else
{
if (lastOK == null) lastOK = pp;
pp = pp.Next;
}
}
outRec.Pts = pp;
}
//----------------------------------------------------------------------
private void FixupFirstLefts1(OutRec OldOutRec, OutRec NewOutRec)
{
for (int i = 0; i < m_PolyOuts.Count; i++)
{
OutRec outRec = m_PolyOuts[i];
if (outRec.Pts != null && outRec.FirstLeft == OldOutRec)
{
if (Poly2ContainsPoly1(outRec.Pts, NewOutRec.Pts, m_UseFullRange))
outRec.FirstLeft = NewOutRec;
}
}
}
//------------------------------------------------------------------------------
bool Param1RightOfParam2(OutRec outRec1, OutRec outRec2)
{
do
{
outRec1 = outRec1.FirstLeft;
if (outRec1 == outRec2) return true;
} while (outRec1 != null);
return false;
}
//------------------------------------------------------------------------------
private OutRec GetLowermostRec(OutRec outRec1, OutRec outRec2)
{
//work out which polygon fragment has the correct hole state ...
if (outRec1.BottomPt == null)
outRec1.BottomPt = GetBottomPt(outRec1.Pts);
if (outRec2.BottomPt == null)
outRec2.BottomPt = GetBottomPt(outRec2.Pts);
OutPt bPt1 = outRec1.BottomPt;
OutPt bPt2 = outRec2.BottomPt;
if (bPt1.Pt.Y > bPt2.Pt.Y) return outRec1;
else if (bPt1.Pt.Y < bPt2.Pt.Y) return outRec2;
else if (bPt1.Pt.X < bPt2.Pt.X) return outRec1;
else if (bPt1.Pt.X > bPt2.Pt.X) return outRec2;
else if (bPt1.Next == bPt1) return outRec2;
else if (bPt2.Next == bPt2) return outRec1;
else if (FirstIsBottomPt(bPt1, bPt2)) return outRec1;
else return outRec2;
}
//------------------------------------------------------------------------------
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 OutRec CreateOutRec()
{
OutRec result = new OutRec();
result.Idx = Unassigned;
result.IsHole = false;
result.IsOpen = false;
result.FirstLeft = null;
result.Pts = null;
result.BottomPt = null;
result.PolyNode = null;
m_PolyOuts.Add(result);
result.Idx = m_PolyOuts.Count - 1;
return result;
}
//------------------------------------------------------------------------------
internal void FixHoleLinkage(OutRec outRec)
{
//skip if an outermost polygon or
//already already points to the correct FirstLeft ...
if (outRec.FirstLeft == null ||
(outRec.IsHole != outRec.FirstLeft.IsHole &&
outRec.FirstLeft.Pts != null)) return;
OutRec orfl = outRec.FirstLeft;
while (orfl != null && ((orfl.IsHole == outRec.IsHole) || orfl.Pts == null))
orfl = orfl.FirstLeft;
outRec.FirstLeft = orfl;
}