GoToSocial/vendor/github.com/golang/geo/s2/region.go
Tobi Smethurst 98263a7de6
Grand test fixup (#138)
* start fixing up tests

* fix up tests + automate with drone

* fiddle with linting

* messing about with drone.yml

* some more fiddling

* hmmm

* add cache

* add vendor directory

* verbose

* ci updates

* update some little things

* update sig
2021-08-12 21:03:24 +02:00

72 lines
2.8 KiB
Go

// Copyright 2014 Google Inc. All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package s2
// A Region represents a two-dimensional region on the unit sphere.
//
// The purpose of this interface is to allow complex regions to be
// approximated as simpler regions. The interface is restricted to methods
// that are useful for computing approximations.
type Region interface {
// CapBound returns a bounding spherical cap. This is not guaranteed to be exact.
CapBound() Cap
// RectBound returns a bounding latitude-longitude rectangle that contains
// the region. The bounds are not guaranteed to be tight.
RectBound() Rect
// ContainsCell reports whether the region completely contains the given region.
// It returns false if containment could not be determined.
ContainsCell(c Cell) bool
// IntersectsCell reports whether the region intersects the given cell or
// if intersection could not be determined. It returns false if the region
// does not intersect.
IntersectsCell(c Cell) bool
// ContainsPoint reports whether the region contains the given point or not.
// The point should be unit length, although some implementations may relax
// this restriction.
ContainsPoint(p Point) bool
// CellUnionBound returns a small collection of CellIDs whose union covers
// the region. The cells are not sorted, may have redundancies (such as cells
// that contain other cells), and may cover much more area than necessary.
//
// This method is not intended for direct use by client code. Clients
// should typically use Covering, which has options to control the size and
// accuracy of the covering. Alternatively, if you want a fast covering and
// don't care about accuracy, consider calling FastCovering (which returns a
// cleaned-up version of the covering computed by this method).
//
// CellUnionBound implementations should attempt to return a small
// covering (ideally 4 cells or fewer) that covers the region and can be
// computed quickly. The result is used by RegionCoverer as a starting
// point for further refinement.
CellUnionBound() []CellID
}
// Enforce Region interface satisfaction.
var (
_ Region = Cap{}
_ Region = Cell{}
_ Region = (*CellUnion)(nil)
_ Region = (*Loop)(nil)
_ Region = Point{}
_ Region = (*Polygon)(nil)
_ Region = (*Polyline)(nil)
_ Region = Rect{}
)