// The implementation is approximate but conservative; it always returns
// "false" if the cell is not contained by the buffered region, but it may
// also return false in some cases where "cell" is in fact contained.
public bool Contains(S2Cell cell)
{
// Return true if the buffered region is guaranteed to cover whole globe.
if (radius_successor_ > S1ChordAngle.Straight)
{
return(true);
}
// To implement this method perfectly would require computing the directed
// Hausdorff distance, which is expensive (and not currently implemented).
// However the following heuristic is almost as good in practice and much
// cheaper to compute.
// Return true if the unbuffered region contains this cell.
if (Index().MakeS2ShapeIndexRegion().Contains(cell))
{
return(true);
}
// Otherwise approximate the cell by its bounding cap.
//
// NOTE(ericv): It would be slightly more accurate to first find the closest
// point in the indexed geometry to the cell, and then measure the actual
// maximum distance from that point to the cell (a poor man's Hausdorff
// distance). But based on actual tests this is not worthwhile.
S2Cap cap = cell.GetCapBound();
if (Radius < cap.Radius)
{
return(false);
}
// Return true if the distance to the cell center plus the radius of the
// cell's bounding cap is less than or equal to "radius_".
var target = new S2ClosestEdgeQuery.PointTarget(cell.Center());
return(query_.IsDistanceLess(target, radius_successor_ - cap.Radius));
}
private static Result TestFindClosestEdges(Target target, S2ClosestEdgeQuery query)
{
List <Result> expected = new(), actual = new();
query.Options_.UseBruteForce = (true);
GetClosestEdges(target, query, expected);
query.Options_.UseBruteForce = (false);
GetClosestEdges(target, query, actual);
Assert.True(TestingDistance.CheckDistanceResults(ConvertResults(expected),
ConvertResults(actual),
query.Options_.MaxResults,
query.Options_.MaxDistance,
query.Options_.MaxError));
if (!expected.Any())
{
return(new Result());
}
// Note that when options.max_error() > 0, expected[0].distance() may not
// be the minimum distance. It is never larger by more than max_error(),
// but the actual value also depends on max_results().
//
// Here we verify that GetDistance() and IsDistanceLess() return results
// that are consistent with the max_error() setting.
var max_error = query.Options_.MaxError;
var min_distance = expected[0].Distance;
Assert.True(query.GetDistance(target) <= min_distance + max_error);
// Test IsDistanceLess().
Assert.False(query.IsDistanceLess(target, min_distance - max_error));
Assert.True(query.IsConservativeDistanceLessOrEqual(target, min_distance));
// Return the closest edge result so that we can also test Project.
return(expected[0]);
}