/**
* Given (i, j) coordinates that may be out of bounds, normalize them by
* returning the corresponding neighbor cell on an adjacent face.
*/
private static function fromFaceIJWrap($face, $i, $j)
{
// Convert i and j to the coordinates of a leaf cell just beyond the
// boundary of this face. This prevents 32-bit overflow in the case
// of finding the neighbors of a face cell, and also means that we
// don't need to worry about the distinction between (s,t) and (u,v).
$i = max(-1, min(self::MAX_SIZE, $i));
$j = max(-1, min(self::MAX_SIZE, $j));
// Find the (s,t) coordinates corresponding to (i,j). At least one
// of these coordinates will be just outside the range [0, 1].
$kScale = 1.0 / self::MAX_SIZE;
$s = $kScale * (($i << 1) + 1 - self::MAX_SIZE);
$t = $kScale * (($j << 1) + 1 - self::MAX_SIZE);
// Find the leaf cell coordinates on the adjacent face, and convert
// them to a cell id at the appropriate level.
$p = S2Projections::faceUvToXyz($face, $s, $t);
$face = S2Projections::xyzToFace($p);
$st = S2Projections::validFaceXyzToUv($face, $p);
return self::fromFaceIJ($face, self::stToIJ($st->x()), self::stToIJ($st->y()));
}
