public static PolyChains Sort(IList <Point2d> points, bool robust = true, double epsilon = MathUtils.EPSILON)
{
PolyChains pchains = new PolyChains(points);
// NOTE: it is not necessary to find the leftmost point. It is enough with finding the start of a chain.
int leftMost = FindLeftMost(points, epsilon);
pchains.LeftMost = leftMost;
IPolyEnumerator <Point2d> eFirst = NewEnumerator(points, leftMost, robust, epsilon);
IPolyEnumerator <Point2d> e = eFirst.Clone();
IPolyEnumerator <Point2d> eNext = e.Clone();
eNext.Next();
if (eNext.Equals(eFirst))
{
}
IPolyEnumerator <Point2d> first = e.Clone();
bool? leftRight = null;
bool? bottomTop = null;
List <int> inflectionYPoints = new List <int>();
do
{
Point2d p = e.Point;
Point2d pNext = eNext.Point;
{
bool?nextBT = null;
if (pNext.Y.EpsilonG(p.Y))
{
nextBT = true;
}
else if (pNext.Y.EpsilonL(p.Y))
{
nextBT = false;
}
if (bottomTop == null)
{
bottomTop = nextBT;
}
else
{
if ((nextBT != null) && (bottomTop != nextBT))
{
inflectionYPoints.Add(e.Index);
}
}
}
{
bool?nextLR = null;
if (pNext.X.EpsilonG(p.X))
{
nextLR = true;
}
else if (pNext.X.EpsilonL(p.X))
{
nextLR = false;
}
if (leftRight == null)
{
leftRight = nextLR;
}
else
{
if ((nextLR != null) && (leftRight != nextLR))
{
pchains.AddChain((bool)leftRight, first, e, inflectionYPoints);
first = e.Clone();
leftRight = null;
bottomTop = null;
inflectionYPoints.Clear();
}
}
}
e.Next();
eNext.Next();
}while (!e.Equals(eFirst));
if (!first.Equals(e))
{
pchains.AddChain((leftRight ?? true), first, e, inflectionYPoints);
}
return(pchains);
/*for (int i = 1; i < points.Count + 1; i++)
* {
* Point2d pprev = points[(leftMost + i - 1) % points.Count];
* Point2d p = points[(leftMost + i) % points.Count];
*
* {
* bool? nextBT = null;
* if (p.Y.EpsilonG(pprev.Y))
* {
* nextBT = true;
* }
* else if (p.Y.EpsilonL(pprev.Y))
* {
* nextBT = false;
* }
*
* if (bottomTop == null)
* {
* bottomTop = nextBT;
* }
* else
* {
* if ((nextBT != null) && (bottomTop != nextBT))
* {
* inflectionYPoints.Add(leftMost + i);
* }
* }
* }
*
* {
* bool? nextLR = null;
* if (p.X.EpsilonG(pprev.X))
* {
* nextLR = true;
* }
* else if (p.X.EpsilonL(pprev.X))
* {
* nextLR = false;
* }
*
* if (leftRight == null)
* {
* leftRight = nextLR;
* }
* else
* {
* if ((nextLR != null) && (leftRight != nextLR))
* {
* pchains.AddChain((bool)leftRight, first, (leftMost + i) - first, inflectionYPoints);
*
* // Rollback
* i--;
*
* first = leftMost + i;
* leftRight = null;
* bottomTop = null;
* inflectionYPoints.Clear();
* }
* }
* }
* }
*
* int c = (leftMost + points.Count + 1) - first;
* if (c > 1)
* {
* pchains.AddChain((leftRight ?? true), first, c, inflectionYPoints);
* }
* return pchains;*/
}
public static IList <IList <Point2d> > Sort2(IList <Point2d> points)
{
PolyChains pchains = Sort(points);
return(pchains.GetMonotoneChains());
}