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);
}