LineIntersector.h

/**********************************************************************
 *
 * GEOS - Geometry Engine Open Source
 * http://geos.osgeo.org
 *
 * Copyright (C) 2005-2006 Refractions Research Inc.
 * Copyright (C) 2001-2002 Vivid Solutions Inc.
 *
 * This is free software; you can redistribute and/or modify it under
 * the terms of the GNU Lesser General Public Licence as published
 * by the Free Software Foundation.
 * See the COPYING file for more information.
 *
 **********************************************************************
 *
 * Last port: algorithm/RobustLineIntersector.java r785 (JTS-1.13+)
 *
 **********************************************************************/
 
#pragma once
 
#include <geos/export.h>
#include <geos/algorithm/Intersection.h>
#include <geos/geom/Coordinate.h>
#include <geos/geom/Envelope.h>
 
#include <string>
 
// Forward declarations
namespace geos {
namespace geom {
class PrecisionModel;
}
}
 
namespace geos {
namespace algorithm { // geos::algorithm
 
class GEOS_DLL LineIntersector {
public:
 
    static double interpolateZ(const geom::Coordinate& p, const geom::Coordinate& p0, const geom::Coordinate& p1);
 
 
    static double computeEdgeDistance(const geom::Coordinate& p, const geom::Coordinate& p0, const geom::Coordinate& p1);
 
    static double nonRobustComputeEdgeDistance(const geom::Coordinate& p, const geom::Coordinate& p1,
            const geom::Coordinate& p2);
 
    explicit LineIntersector(const geom::PrecisionModel* initialPrecisionModel = nullptr)
        :
        precisionModel(initialPrecisionModel),
        result(0),
        inputLines(),
        isProperVar(false)
    {}
 
    ~LineIntersector() = default;
 
    bool isInteriorIntersection()
    {
        if(isInteriorIntersection(0)) {
            return true;
        }
        if(isInteriorIntersection(1)) {
            return true;
        }
        return false;
    };
 
    bool isInteriorIntersection(std::size_t inputLineIndex)
    {
        for(std::size_t i = 0; i < result; ++i) {
            if(!(intPt[i].equals2D(*inputLines[inputLineIndex][0])
                 || intPt[i].equals2D(*inputLines[inputLineIndex][1]))) {
                return true;
            }
        }
        return false;
    };
 
    void
    setPrecisionModel(const geom::PrecisionModel* newPM)
    {
        precisionModel = newPM;
    }
 
    void computeIntersection(const geom::Coordinate& p, const geom::Coordinate& p1, const geom::Coordinate& p2);
 
    static bool hasIntersection(const geom::Coordinate& p, const geom::Coordinate& p1, const geom::Coordinate& p2);
 
    enum intersection_type : uint8_t {
        NO_INTERSECTION = 0,
 
        POINT_INTERSECTION = 1,
 
        COLLINEAR_INTERSECTION = 2
    };
 
    void computeIntersection(const geom::Coordinate& p1, const geom::Coordinate& p2,
                             const geom::Coordinate& p3, const geom::Coordinate& p4);
 
    std::string toString() const;
 
    bool
    hasIntersection() const
    {
        return result != NO_INTERSECTION;
    }
 
 
    const geom::Coordinate*
    getEndpoint(std::size_t segmentIndex, std::size_t ptIndex) const
    {
        return inputLines[segmentIndex][ptIndex];
    }
 
    size_t
    getIntersectionNum() const
    {
        return result;
    }
 
 
    const geom::Coordinate&
    getIntersection(std::size_t intIndex) const
    {
        return intPt[intIndex];
    }
 
    static bool isSameSignAndNonZero(double a, double b);
 
    bool isIntersection(const geom::Coordinate& pt) const
    {
        for(std::size_t i = 0; i < result; ++i) {
            if(intPt[i].equals2D(pt)) {
                return true;
            }
        }
        return false;
    };
 
    bool
    isProper() const
    {
        return hasIntersection() && isProperVar;
    }
 
    const geom::Coordinate& getIntersectionAlongSegment(std::size_t segmentIndex, std::size_t intIndex);
 
    std::size_t getIndexAlongSegment(std::size_t segmentIndex, std::size_t intIndex);
 
    double getEdgeDistance(std::size_t geomIndex, std::size_t intIndex) const;
 
private:
 
    const geom::PrecisionModel* precisionModel;
 
    std::size_t result;
 
    const geom::Coordinate* inputLines[2][2];
 
    geom::Coordinate intPt[2];
 
    std::size_t intLineIndex[2][2];
 
    bool isProperVar;
    //Coordinate &pa;
    //Coordinate &pb;
 
    bool
    isCollinear() const
    {
        return result == COLLINEAR_INTERSECTION;
    }
 
    uint8_t computeIntersect(const geom::Coordinate& p1, const geom::Coordinate& p2,
                             const geom::Coordinate& q1, const geom::Coordinate& q2);
 
    bool
    isEndPoint() const
    {
        return hasIntersection() && !isProperVar;
    }
 
    void computeIntLineIndex();
 
    void computeIntLineIndex(std::size_t segmentIndex);
 
    uint8_t computeCollinearIntersection(const geom::Coordinate& p1, const geom::Coordinate& p2,
                                         const geom::Coordinate& q1, const geom::Coordinate& q2);
 
    geom::Coordinate intersection(const geom::Coordinate& p1,
                                  const geom::Coordinate& p2,
                                  const geom::Coordinate& q1,
                                  const geom::Coordinate& q2) const;
 
    bool isInSegmentEnvelopes(const geom::Coordinate& pt) const
    {
        geom::Envelope env0(*inputLines[0][0], *inputLines[0][1]);
        geom::Envelope env1(*inputLines[1][0], *inputLines[1][1]);
        return env0.contains(pt) && env1.contains(pt);
    };
 
    geom::Coordinate intersectionSafe(const geom::Coordinate& p1, const geom::Coordinate& p2,
                                      const geom::Coordinate& q1, const geom::Coordinate& q2) const
    {
        geom::Coordinate ptInt = Intersection::intersection(p1, p2, q1, q2);
        if (ptInt.isNull()) {
            ptInt = nearestEndpoint(p1, p2, q1, q2);
        }
        return ptInt;
    };
 
    static geom::Coordinate nearestEndpoint(const geom::Coordinate& p1,
                                            const geom::Coordinate& p2,
                                            const geom::Coordinate& q1,
                                            const geom::Coordinate& q2);
 
    static double zGet(
        const geom::Coordinate& p,
        const geom::Coordinate& q)
    {
        double z = p.z;
        if ( std::isnan(z) ) {
            z = q.z; // may be NaN
        }
        return z;
    };
 
    static double zGetOrInterpolate(
        const geom::Coordinate& p,
        const geom::Coordinate& p1,
        const geom::Coordinate& p2)
    {
        double z = p.z;
        if (! std::isnan(z) ) return z;
        return zInterpolate(p, p1, p2); // may be NaN
    };
 
    static geom::Coordinate zGetOrInterpolateCopy(
        const geom::Coordinate& p,
        const geom::Coordinate& p1,
        const geom::Coordinate& p2)
    {
        geom::Coordinate pCopy = p;
        double z = zGetOrInterpolate(p, p1, p2);
        pCopy.z = z;
        return pCopy;
    };
 
    static double zInterpolate(const geom::Coordinate& p,
                               const geom::Coordinate& p0,
                               const geom::Coordinate& p1);
 
    static double zInterpolate(const geom::Coordinate& p,
                               const geom::Coordinate& p1,
                               const geom::Coordinate& p2,
                               const geom::Coordinate& q1,
                               const geom::Coordinate& q2);
 
};
 
 
} // namespace geos::algorithm
} // namespace geos