internal static bool IsClockwiseRing(com.epl.geometry.MultiPathImpl polygon, int iring)
{
int high_point_index = polygon.GetHighestPointIndex(iring);
int path_start = polygon.GetPathStart(iring);
int path_end = polygon.GetPathEnd(iring);
com.epl.geometry.Point2D q = polygon.GetXY(high_point_index);
com.epl.geometry.Point2D p;
com.epl.geometry.Point2D r;
if (high_point_index == path_start)
{
p = polygon.GetXY(path_end - 1);
r = polygon.GetXY(path_start + 1);
}
else
{
if (high_point_index == path_end - 1)
{
p = polygon.GetXY(high_point_index - 1);
r = polygon.GetXY(path_start);
}
else
{
p = polygon.GetXY(high_point_index - 1);
r = polygon.GetXY(high_point_index + 1);
}
}
int orientation = com.epl.geometry.Point2D.OrientationRobust(p, q, r);
if (orientation == 0)
{
return(polygon.CalculateRingArea2D(iring) > 0.0);
}
return(orientation == -1);
}
public static int IsPointInAnyOuterRing(com.epl.geometry.Polygon inputPolygon, com.epl.geometry.Point2D inputPoint, double tolerance)
{
com.epl.geometry.Envelope2D env = new com.epl.geometry.Envelope2D();
inputPolygon.QueryLooseEnvelope(env);
env.Inflate(tolerance, tolerance);
if (!env.Contains(inputPoint))
{
return(0);
}
// Note:
// Wolfgang had noted that this could be optimized if the exterior rings
// have positive area:
// Only test the positive rings and bail out immediately when in a
// positive ring.
// The worst case complexity is still O(n), but on average for polygons
// with holes, that would be faster.
// However, that method would not work if polygon is reversed, while the
// one here works fine same as PointInPolygon.
bool bAltenate = false;
// use winding in this test
com.epl.geometry.PointInPolygonHelper helper = new com.epl.geometry.PointInPolygonHelper(bAltenate, inputPoint, tolerance);
com.epl.geometry.MultiPathImpl mpImpl = (com.epl.geometry.MultiPathImpl)inputPolygon._getImpl();
com.epl.geometry.SegmentIteratorImpl iter = mpImpl.QuerySegmentIterator();
while (iter.NextPath())
{
double ringArea = mpImpl.CalculateRingArea2D(iter.GetPathIndex());
bool bIsHole = ringArea < 0;
if (!bIsHole)
{
helper.m_windnum = 0;
while (iter.HasNextSegment())
{
com.epl.geometry.Segment segment = iter.NextSegment();
if (helper.ProcessSegment(segment))
{
return(-1);
}
}
// point on boundary
if (helper.m_windnum != 0)
{
return(1);
}
}
}
return(helper.Result());
}