Box.h

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/*
 * This file is part of sphgeom.
 *
 * Developed for the LSST Data Management System.
 * This product includes software developed by the LSST Project
 * (http://www.lsst.org).
 * See the COPYRIGHT file at the top-level directory of this distribution
 * for details of code ownership.
 *
 * This software is dual licensed under the GNU General Public License and also
 * under a 3-clause BSD license. Recipients may choose which of these licenses
 * to use; please see the files gpl-3.0.txt and/or bsd_license.txt,
 * respectively.  If you choose the GPL option then the following text applies
 * (but note that there is still no warranty even if you opt for BSD instead):
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
#ifndef LSST_SPHGEOM_BOX_H_
#define LSST_SPHGEOM_BOX_H_

 
#include <iosfwd>
#include <cstdint>
 
#include "AngleInterval.h"
#include "LonLat.h"
#include "NormalizedAngleInterval.h"
#include "Region.h"
#include "UnitVector3d.h"
 
 
namespace lsst {
namespace sphgeom {

class Box : public Region {
public:
    static constexpr std::uint8_t TYPE_CODE = 'b';
 
    // Factory functions
    static Box fromDegrees(double lon1, double lat1, double lon2, double lat2) {
        return Box(NormalizedAngleInterval::fromDegrees(lon1, lon2),
                   AngleInterval::fromDegrees(lat1, lat2));
    }
 
    static Box fromRadians(double lon1, double lat1, double lon2, double lat2) {
        return Box(NormalizedAngleInterval::fromRadians(lon1, lon2),
                   AngleInterval::fromRadians(lat1, lat2));
    }
 
    static Box empty() { return Box(); }
 
    static Box full() { return Box(allLongitudes(), allLatitudes()); }

    static NormalizedAngle halfWidthForCircle(Angle r, Angle lat);

    static NormalizedAngleInterval allLongitudes() {
        return NormalizedAngleInterval::full();
    }

    static AngleInterval allLatitudes() {
        return AngleInterval(Angle(-0.5 * PI), Angle(0.5 * PI));
    }

    Box() {}

    explicit Box(LonLat const & p) :
        _lon(p.getLon()),
        _lat(p.getLat())
    {
        _enforceInvariants();
    }

    Box(LonLat const & p1, LonLat const & p2) :
        _lon(p1.getLon(), p2.getLon()),
        _lat(p1.getLat(), p2.getLat())
    {
        _enforceInvariants();
    }

    Box(LonLat const & p, Angle w, Angle h) :
        _lon(NormalizedAngleInterval(p.getLon()).dilatedBy(w)),
        _lat(AngleInterval(p.getLat()).dilatedBy(h))
    {
        _enforceInvariants();
    }

    Box(NormalizedAngleInterval const & lon, AngleInterval const & lat) :
        _lon(lon),
        _lat(lat)
    {
        _enforceInvariants();
    }

    bool operator==(Box const & b) const {
        return _lon == b._lon && _lat == b._lat;
    }
 
    bool operator!=(Box const & b) const { return !(*this == b); }

    bool operator==(LonLat const & p) const {
        return _lat == p.getLat() && _lon == p.getLon();
    }
 
    bool operator!=(LonLat const & p) const { return !(*this == p); }

    NormalizedAngleInterval const & getLon() const { return _lon; }

    AngleInterval const & getLat() const { return _lat; }

    bool isEmpty() const override { return _lat.isEmpty(); }

    bool isFull() const { return _lon.isFull() && _lat == allLatitudes(); }

    LonLat getCenter() const {
        return LonLat(_lon.getCenter(), _lat.getCenter());
    }

    NormalizedAngle getWidth() const { return _lon.getSize(); }

    Angle getHeight() const { return _lat.getSize(); }

    bool contains(LonLat const & x) const {
        return _lat.contains(x.getLat()) && _lon.contains(x.getLon());
    }
 
    bool contains(Box const & x) const {
        return _lat.contains(x._lat) && _lon.contains(x._lon);
    }

    bool isDisjointFrom(LonLat const & x) const { return !intersects(x); }
 
    bool isDisjointFrom(Box const & x) const { return !intersects(x); }

    bool intersects(LonLat const & x) const {
        return _lat.intersects(x.getLat()) && _lon.intersects(x.getLon());
    }
 
    bool intersects(Box const & x) const {
        return _lat.intersects(x._lat) && _lon.intersects(x._lon);
    }

    bool isWithin(LonLat const & x) const {
        return _lat.isWithin(x.getLat()) && _lon.isWithin(x.getLon());
    }
 
    bool isWithin(Box const & x) const {
        return _lat.isWithin(x._lat) && _lon.isWithin(x._lon);
    }

    Box & clipTo(LonLat const & x) {
        _lon.clipTo(x.getLon());
        _lat.clipTo(x.getLat());
        _enforceInvariants();
        return *this;
    }

    Box & clipTo(Box const & x) {
        _lon.clipTo(x.getLon());
        _lat.clipTo(x.getLat());
        _enforceInvariants();
        return *this;
    }

    Box clippedTo(LonLat const & x) const { return Box(*this).clipTo(x); }

    Box clippedTo(Box const & x) const { return Box(*this).clipTo(x); }

    Box & expandTo(LonLat const & x) {
        _lon.expandTo(x.getLon());
        _lat.expandTo(x.getLat());
        return *this;
    }
 
    Box & expandTo(Box const & x) {
        _lon.expandTo(x.getLon());
        _lat.expandTo(x.getLat());
        return *this;
    }

    Box expandedTo(LonLat const & x) const { return Box(*this).expandTo(x); }
    Box expandedTo(Box const & x) const { return Box(*this).expandTo(x); }

    Box & dilateBy(Angle r);
    Box dilatedBy(Angle r) const { return Box(*this).dilateBy(r); }

    Box & dilateBy(Angle w, Angle h);
    Box dilatedBy(Angle w, Angle h) const { return Box(*this).dilateBy(w, h); }
    Box & erodeBy(Angle r) { return dilateBy(-r); }
    Box & erodeBy(Angle w, Angle h) { return dilateBy(-w, -h); }
    Box erodedBy(Angle r) const { return dilatedBy(-r);  }
    Box erodedBy(Angle w, Angle h) const { return dilatedBy(-w, -h);  }
 
    Relationship relate(LonLat const & p) const { return relate(Box(p)); }

    double getArea() const;
 
    // Region interface
    std::unique_ptr<Region> clone() const override {
        return std::unique_ptr<Box>(new Box(*this));
    }
 
    Box getBoundingBox() const override { return *this; }
    Box3d getBoundingBox3d() const override;
    Circle getBoundingCircle() const override;
 
    bool contains(UnitVector3d const & v) const override {
        return contains(LonLat(v));
    }
 
    using Region::contains;
 
    Relationship relate(Region const & r) const override {
        // Dispatch on the type of r.
        return invert(r.relate(*this));
    }
 
    Relationship relate(Box const & b) const override {
        Relationship r1 = _lon.relate(b._lon);
        Relationship r2 = _lat.relate(b._lat);
        // If the box longitude or latitude intervals are disjoint, then the
        // boxes are disjoint. The other spatial relationships must hold for
        // both the longitude and latitude intervals in order to hold for the
        // boxes.
        return ((r1 & r2) & (CONTAINS | WITHIN)) | ((r1 | r2) & DISJOINT);
    }
 
    Relationship relate(Circle const &) const override;
    Relationship relate(ConvexPolygon const &) const override;
    Relationship relate(Ellipse const &) const override;
 
    TriState overlaps(Region const& other) const override {
        return other.overlaps(*this);
    }
    TriState overlaps(Box const &) const override;
    TriState overlaps(Circle const &) const override;
    TriState overlaps(ConvexPolygon const &) const override;
    TriState overlaps(Ellipse const &) const override;
 
    std::vector<std::uint8_t> encode() const override;

    static std::unique_ptr<Box> decode(std::vector<std::uint8_t> const & s) {
        return decode(s.data(), s.size());
    }
    static std::unique_ptr<Box> decode(std::uint8_t const * buffer, size_t n);
 
private:
    static constexpr size_t ENCODED_SIZE = 33;
 
    void _enforceInvariants() {
        // Make sure that _lat ⊆ [-π/2, π/2].
        _lat.clipTo(allLatitudes());
        // Make sure that both longitude and latitude intervals are
        // empty, or neither is. This simplifies the implementation
        // of the spatial relation tests.
        if (_lat.isEmpty()) {
            _lon = NormalizedAngleInterval();
        } else if (_lon.isEmpty()) {
            _lat = AngleInterval();
        }
    }
 
    NormalizedAngleInterval _lon;
    AngleInterval _lat;
};
 
std::ostream & operator<<(std::ostream &, Box const &);
 
}} // namespace lsst::sphgeom
 
#endif // LSST_SPHGEOM_BOX_H_