private readonly int orientation_; // Hilbert curve orientation of this cell (see s2coords.h) #region Constructors // Construct an S2PaddedCell for the given cell id and padding. public S2PaddedCell(S2CellId id, double padding) { ij_lo_ = new int[2]; Id = id; Padding = padding; if (Id.IsFace()) { // Fast path for constructing a top-level face (the most common case). double limit = 1 + padding; Bound = new R2Rect(new R1Interval(-limit, limit), new R1Interval(-limit, limit)); middle_ = new R2Rect(new R1Interval(-padding, padding), new R1Interval(-padding, padding)); ij_lo_[0] = ij_lo_[1] = 0; orientation_ = (int)(Id.Face() & 1); Level = 0; } else { var ij = new int[2]; id.ToFaceIJOrientation(out ij[0], out ij[1], out orientation_, true); Level = id.Level(); Bound = S2CellId.IJLevelToBoundUV(ij, Level).Expanded(padding); int ij_size = S2CellId.SizeIJ(Level); ij_lo_[0] = ij[0] & -ij_size; ij_lo_[1] = ij[1] & -ij_size; } }