private static bool Param1RightOfParam2(OutRec outRec1, OutRec outRec2)
{
Contract.Requires(outRec1 != null);
do
{
outRec1 = outRec1.FirstLeft;
if (outRec1 == outRec2)
return true;
} while (outRec1 != null);
return false;
}
private static void UpdateOutPtIdxs(OutRec outRec)
{
Contract.Requires(outRec != null);
Contract.Requires(outRec.Pts != null);
var op = outRec.Pts;
do
{
op = op.Prev;
} while (op != outRec.Pts);
}
private static void FixupOutPolygon(OutRec outRec)
{
Contract.Requires(outRec != null);
Contract.Requires(outRec.Pts != null);
//FixupOutPolygon() - removes duplicate points and simplifies consecutive
//parallel edges by removing the middle vertex.
OutPt lastOk = null;
outRec.BottomPt = null;
var pp = outRec.Pts;
for (;;)
{
if (pp.Prev == pp || pp.Prev == pp.Next)
{
DisposeOutPts(pp);
outRec.Pts = null;
return;
}
//test for duplicate points and for same slope (cross-product) ...
if (pp.Pt.Equals(pp.Next.Pt) || InternalHelpers.SlopesEqual(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 static OutRec GetLowermostRec(OutRec outRec1, OutRec outRec2)
{
Contract.Requires(outRec2 != null);
Contract.Requires(outRec1 != null);
//work out which polygon fragment has the correct hole state ...
if (outRec1.BottomPt == null)
outRec1.BottomPt = outRec1.Pts.GetBottomPt();
if (outRec2.BottomPt == null)
outRec2.BottomPt = outRec2.Pts.GetBottomPt();
var bPt1 = outRec1.BottomPt;
var 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 (InternalHelpers.FirstIsBottomPt(bPt1, bPt2))
return outRec1;
else
return outRec2;
}
private static void FixHoleLinkage(OutRec outRec)
{
Contract.Requires(outRec != null);
//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;
var orfl = outRec.FirstLeft;
while (orfl != null && ((orfl.IsHole == outRec.IsHole) || orfl.Pts == null))
orfl = orfl.FirstLeft;
outRec.FirstLeft = orfl;
}
private void SetHoleState(TEdge e, OutRec outRec)
{
Contract.Requires(e != null);
var isHole = false;
var e2 = e.PrevInAEL;
while (e2 != null)
{
if (e2.OutIdx >= 0)
{
isHole = !isHole;
if (outRec.FirstLeft == null)
outRec.FirstLeft = _polyOuts[e2.OutIdx];
}
e2 = e2.PrevInAEL;
}
if (isHole)
outRec.IsHole = true;
}
private void FixupFirstLefts2(OutRec oldOutRec, OutRec newOutRec)
{
foreach (var outRec in _polyOuts.Where(outRec => outRec.FirstLeft == oldOutRec))
outRec.FirstLeft = newOutRec;
}
private void FixupFirstLefts1(OutRec oldOutRec, OutRec newOutRec)
{
foreach (var outRec in _polyOuts.Where(outRec => outRec.Pts != null && outRec.FirstLeft == oldOutRec && Poly2ContainsPoly1(outRec.Pts, newOutRec.Pts)))
outRec.FirstLeft = newOutRec;
}
private OutRec CreateOutRec()
{
var result = new OutRec {
Idx = -1,
IsHole = false,
FirstLeft = null,
Pts = null,
BottomPt = null,
PolyNode = null
};
_polyOuts.Add(result);
result.Idx = _polyOuts.Count - 1;
return result;
}