/**
* Indica si el punto está en el borde del poligono.
*/
public static bool PointInEdge(IList <Point2d> points, Point2d p, bool robust = true, double epsilon = MathUtils.EPSILON)
{
double epsilon2 = epsilon * epsilon;
DistPointSegment2 dist = new DistPointSegment2();
dist.Point = p;
IPolyEnumerator <Point2d> eFirst = NewEnumerator(points, 0, robust, epsilon);
IPolyEnumerator <Point2d> e = eFirst.Clone();
IPolyEnumerator <Point2d> eNext = e.Clone();
eNext.Next();
if (eNext.Equals(eFirst))
{
return(false);
}
do
{
dist.Segment = new Segment2(e.Point, eNext.Point);
if (dist.CalcDistance2().EpsilonEquals(0, epsilon2))
{
return(true);
}
e.Next();
eNext.Next();
}while (!e.Equals(eFirst));
return(false);
}
/**
* Area del poligono con signo.
* <p>
* {@link http://paulbourke.net/geometry/polyarea/}
*
* @param points Puntos del poligono.
* @return Area (con signo).
*/
public static double SignedArea(IList <Point2d> points, bool robust = true, double epsilon = MathUtils.EPSILON)
{
if (points.Count < 3)
{
return(0);
}
double area = 0;
IPolyEnumerator <Point2d> eFirst = NewEnumerator(points, 0, robust, epsilon);
IPolyEnumerator <Point2d> e = eFirst.Clone();
IPolyEnumerator <Point2d> eNext = e.Clone();
eNext.Next();
if (eNext.Equals(eFirst))
{
return(0);
}
do
{
area += e.Point.X * eNext.Point.Y - e.Point.Y * eNext.Point.X;
e.Next();
eNext.Next();
}while (!e.Equals(eFirst));
return(area / 2);
}
public void AddChain(bool leftToRight, IPolyEnumerator <Point2d> startIndex, IPolyEnumerator <Point2d> endIndex, List <int> inflectionYPoints)
{
int count = endIndex.Index - startIndex.Index + 1;
if (count < 0)
{
count += this.Points.Count;
}
this.AddChain(leftToRight, startIndex.Index, count, inflectionYPoints);
}
/**
* This method tests the orientation of a simple polygon.
* <p>
* {@link http://geometryalgorithms.com/Archive/algorithm_0101/algorithm_0101.htm#orientation2D_polygon()}
* {@link http://geomalgorithms.com/a01-_area.html#orientation2D_polygon%28%29}
*/
public static Orientation TestOrientation(IList <Point2d> points, bool robust = true, double epsilon = MathUtils.EPSILON)
{
int n = points.Count;
if (n < 3)
{
return(Orientation.Degenerate);
}
// first find leftmost lowest vertex of the polygon
int index = FindLeftMost(points, epsilon);
IPolyEnumerator <Point2d> e = NewEnumerator(points, index, robust, epsilon);
// test orientation at leftmost vertex
// ccw <=> the edge leaving is left of the entering edge
IPolyEnumerator <Point2d> eNext = e.Clone();
eNext.Next();
if (eNext.Equals(e))
{
return(Orientation.Degenerate);
}
IPolyEnumerator <Point2d> ePrev = e.Clone();
ePrev.Prev();
if (ePrev.Equals(e))
{
return(Orientation.Degenerate);
}
switch (Point2d.WhichSide(ePrev.Point, e.Point, eNext.Point))
{
case LineSide.Middle:
return(Orientation.Degenerate);
case LineSide.Left:
return(Orientation.CCW);
case LineSide.Right:
return(Orientation.CW);
default:
throw new IndexOutOfRangeException();
}
// Another algorithms:
// http://www.easywms.com/easywms/?q=en/node/3602
// http://paulbourke.net/geometry/clockwise/
// http://paulbourke.net/geometry/polygonmesh/
//
// http://www.easywms.com/easywms/?q=en/node/3602
// http://paulbourke.net/geometry/clockwise/
// http://paulbourke.net/geometry/polygonmesh/
}
/**
* Evaluates the plane where all points are contained. If it does not exist, it returns {@code null}.
*/
public static Plane3d Plane(IList <Point3d> points, bool robust = true, double epsilon = MathUtils.EPSILON)
{
if (points.Count < 3)
{
// Poligono degenerado.
return(null);
}
IPolyEnumerator <Point3d> eFirst = NewEnumerator(points, 0, robust, epsilon);
IPolyEnumerator <Point3d> e1 = eFirst.Clone();
IPolyEnumerator <Point3d> e2 = e1.Clone();
e2.Next();
if (e2.Equals(eFirst))
{
// Poligono degenerado.
return(null);
}
IPolyEnumerator <Point3d> e3 = e2.Clone();
e3.Next();
while (!e3.Equals(eFirst) && AlignmentPoints(e1.Point, e2.Point, e3.Point))
{
e3.Next();
}
if (e3.Equals(eFirst))
{
// Poligono degenerado.
return(null);
}
Plane3d plane = Plane3d.NewOrthonormal(e1.Point, e2.Point, e3.Point);
IPolyEnumerator <Point3d> e4 = e3.Clone();
e4.Next();
while (!e4.Equals(eFirst))
{
if (plane.WhichSide(e4.Point) != PlaneSide.Middle)
{
// Se ha encontrado un punto que no esta en el plano.
return(null);
}
e4.Next();
}
// Se ha terminado correctamente.
return(plane);
}
public IPolyEnumerator <TPoint> Clone()
{
IPolyEnumerator <TPoint> copy = (IPolyEnumerator <TPoint>) this.MemberwiseClone();
return(copy);
}
public bool Equals(IPolyEnumerator <TPoint> other)
{
return(this.index == other.Index);
}
/**
* Indica si un poligo es convexo. Da problemas con poligonos que contengan vertices repetidos.
*/
public static bool IsConvex(IList <Point2d> points, bool robust = true, double epsilon = MathUtils.EPSILON)
{
if (points.Count < 3)
{
return(false);
}
// Indicadores de giro.
bool leftTurn = false, rightTurn = false;
IPolyEnumerator <Point2d> eFirst = NewEnumerator(points, 0, robust, epsilon);
IPolyEnumerator <Point2d> e1 = eFirst.Clone();
IPolyEnumerator <Point2d> e2 = e1.Clone();
e2.Next();
if (e2.Equals(eFirst))
{
return(false);
}
IPolyEnumerator <Point2d> e3 = e2.Clone();
e3.Next();
if (e3.Equals(eFirst))
{
return(false);
}
do
{
switch (Point2d.WhichSide(e1.Point, e2.Point, e3.Point))
{
case LineSide.Left:
leftTurn = true;
break;
case LineSide.Right:
rightTurn = true;
break;
}
// Si se ha girado a izquierda y derecha, no es convexo.
if (leftTurn && rightTurn)
{
return(false);
}
e1.Next();
e2.Next();
e3.Next();
}while (!e1.Equals(eFirst));
// Si no se ha encontrado giro, caso degenerado.
if (!leftTurn && !rightTurn)
{
return(false);
}
return(true);
}
/**
* Winding number test for a point in a polygon. http://geomalgorithms.com/a03-_inclusion.html
* <ul>
* <li>non extendedAlgorithm: Points on a right-side boundary edge being outside, and ones on a left-side edge being inside.</li>
* <li>extendedAlgorithm: This algorithm differenciates between inside/outside/on the polygon.<li>
* </ul>
*/
public static PointInPoly PointInPolyNonZero(IList <Point2d> points, Point2d p, bool extendedAlgorithm, bool robust = true, double epsilon = MathUtils.EPSILON)
{
// the winding number counter
int wn = 0;
IPolyEnumerator <Point2d> eFirst = NewEnumerator(points, 0, robust, epsilon);
IPolyEnumerator <Point2d> e = eFirst.Clone();
IPolyEnumerator <Point2d> eNext = e.Clone();
eNext.Next();
if (eNext.Equals(eFirst))
{
return(PointInPoly.Outside);
}
// loop through all edges of the polygon
do
{
// Segmento ab.
Point2d a = e.Point;
Point2d b = eNext.Point;
if (extendedAlgorithm)
{
// Horizontal line.
if (a.Y.EpsilonEquals(b.Y, epsilon))
{
if (p.Y.EpsilonEquals(a.Y, epsilon))
{
double min, max;
if (a.X < b.X)
{
min = a.X;
max = b.X;
}
else
{
min = b.X;
max = a.X;
}
if (p.X.EpsilonBetweenClosed(min, max, epsilon))
{
return(PointInPoly.On);
}
}
// No se cuenta.
continue;
}
}
if (p.Y.EpsilonGE(a.Y, epsilon))
{
// an upward crossing
if (p.Y.EpsilonL(b.Y, epsilon))
{
// P left of edge
switch (Point2d.WhichSide(a, b, p, epsilon))
{
case LineSide.Left:
// have a valid up intersect
wn++;
break;
case LineSide.Middle:
if (extendedAlgorithm)
{
return(PointInPoly.On);
}
break;
}
}
}
else // if (p.Y.EpsilonL(a.Y, epsilon))
{
// a downward crossing
if (p.Y.EpsilonGE(b.Y, epsilon))
{
// P right of edge
switch (Point2d.WhichSide(a, b, p, epsilon))
{
case LineSide.Right:
// have a valid down intersect
wn--;
break;
case LineSide.Middle:
if (extendedAlgorithm)
{
return(PointInPoly.On);
}
break;
}
}
}
e.Next();
eNext.Next();
}while (!e.Equals(eFirst));
// == 0 only if P is outside
return((wn != 0) ? PointInPoly.Inside : PointInPoly.Outside);
}
/**
* Crossing number test for a point in a polygon. http://geomalgorithms.com/a03-_inclusion.html
* <ul>
* <li>non extendedAlgorithm: Points on a right-side boundary edge being outside, and ones on a left-side edge being inside.</li>
* <li>extendedAlgorithm: This algorithm differenciates between inside/outside/on the polygon.<li>
* </ul>
*/
public static PointInPoly PointInPolyEvenOdd(IList <Point2d> points, Point2d p, bool extendedAlgorithm, bool robust = true, double epsilon = MathUtils.EPSILON)
{
// the crossing number counter
int cn = 0;
IPolyEnumerator <Point2d> eFirst = NewEnumerator(points, 0, robust, epsilon);
IPolyEnumerator <Point2d> e = eFirst.Clone();
IPolyEnumerator <Point2d> eNext = e.Clone();
eNext.Next();
if (eNext.Equals(eFirst))
{
return(PointInPoly.Outside);
}
// loop through all edges of the polygon
do
{
// Segmento ab.
Point2d a = e.Point;
Point2d b = eNext.Point;
if (extendedAlgorithm)
{
// Horizontal line.
if (a.Y.EpsilonEquals(b.Y, epsilon))
{
if (p.Y.EpsilonEquals(a.Y, epsilon))
{
double min, max;
if (a.X < b.X)
{
min = a.X;
max = b.X;
}
else
{
min = b.X;
max = a.X;
}
if (p.X.EpsilonBetweenClosed(min, max, epsilon))
{
return(PointInPoly.On);
}
}
// No se cuenta.
continue;
}
}
if ((p.Y.EpsilonGE(a.Y, epsilon))
? (p.Y.EpsilonL(b.Y, epsilon)) // an upward crossing
: (p.Y.EpsilonGE(b.Y, epsilon))) // a downward crossing
{
// compute the actual edge-ray intersect x-coordinate
double vt = (p.Y - a.Y) / (b.Y - a.Y);
double x = a.X + vt * (b.X - a.X);
if (p.X.EpsilonEquals(x, epsilon))
{
if (extendedAlgorithm)
{
return(PointInPoly.On);
}
}
else if (p.X.EpsilonL(x, epsilon))
{
// a valid crossing of y=P.Y right of P.X
cn++;
}
}
e.Next();
eNext.Next();
}while (!e.Equals(eFirst));
// 0 = outside, 1 = inside
// 0 if even (out), and 1 if odd (in)
return(((cn & 1) == 1) ? PointInPoly.Inside : PointInPoly.Outside);
}
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;*/
}
