GetNearestPoints Enumerate through nearest points in STRTree

NearestPointsNetTopologySuite.cs

    namespace Ex{
      class Example{
        public static IEnumerable<Point> GetNearestPoints(STRtree<Point> tree, Point p)
        {
            var returnedSet = new HashSet<Point>();
            returnedSet.Add(p);
            var dist = new FilteredItemDistance(returnedSet);
            while (true)
            {
                var nearest = tree.NearestNeighbour(p.Boundary.EnvelopeInternal, p, dist);
                if (returnedSet.Contains(nearest)) break;
                yield return nearest;
                returnedSet.Add(nearest);
            }
        }
      }
      public class FilteredItemDistance : IItemDistance<Envelope, Point>
      {
          private ISet<Point> ignorePoints;
          private IItemDistance<Envelope, IGeometry> D = new GeometryItemDistance();
  
          public FilteredItemDistance(ISet<Point> ignorePoints)
          {
              this.ignorePoints = ignorePoints;
          }
  
  
          public double Distance(IBoundable<Envelope, Point> item1, IBoundable<Envelope, Point> item2)
          {
              if (ignorePoints.Contains(item1.Item)) return double.MaxValue;
              return D.Distance(item1, item2);
          }
      }
    }