OverlapUnion.h

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/**********************************************************************
 *
 * GEOS - Geometry Engine Open Source
 * http://trac.osgeo.org/geos
 *
 * Copyright (C) 2011 Sandro Santilli <strk@kbt.io>
 *
 * 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: ORIGINAL WORK, generalization of CascadedPolygonUnion
 *
 **********************************************************************/

#ifndef GEOS_OP_UNION_OVERLAPUNION_H
#define GEOS_OP_UNION_OVERLAPUNION_H

#include <geos/export.h>

#include <vector>
#include <algorithm>
#include <unordered_set>

#include <geos/geom/Geometry.h>
#include <geos/operation/union/UnionStrategy.h>
#include <geos/operation/union/CascadedPolygonUnion.h>

// Forward declarations
namespace geos {
namespace geom {
class Envelope;
class LineSegment;
}
}

namespace geos {
namespace operation { // geos::operation
namespace geounion {  // geos::operation::geounion

class GEOS_DLL OverlapUnion {

public:

    OverlapUnion(const geom::Geometry* p_g0, const geom::Geometry* p_g1, geounion::UnionStrategy* unionFun)
        : g0(p_g0)
        , g1(p_g1)
        , unionFunction(unionFun)
        , geomFactory(p_g0->getFactory())
        , isUnionSafe(false)
        {};

    OverlapUnion(const geom::Geometry* p_g0, const geom::Geometry* p_g1)
        : OverlapUnion(p_g0, p_g1, &defaultUnionFunction)
        {};


    std::unique_ptr<geom::Geometry> doUnion();

private:

    const geom::Geometry* g0;
    const geom::Geometry* g1;
    geounion::UnionStrategy* unionFunction;
    const geom::GeometryFactory* geomFactory;
    bool isUnionSafe;

    geounion::ClassicUnionStrategy defaultUnionFunction;

    geom::Envelope overlapEnvelope(const geom::Geometry* geom0, const geom::Geometry* geom1);
    std::unique_ptr<geom::Geometry> extractByEnvelope(const geom::Envelope& env, const geom::Geometry* geom, std::vector<std::unique_ptr<geom::Geometry>>& disjointGeoms);
    std::unique_ptr<geom::Geometry> combine(std::unique_ptr<geom::Geometry>& unionGeom, std::vector<std::unique_ptr<geom::Geometry>>& disjointPolys);
    std::unique_ptr<geom::Geometry> unionFull(const geom::Geometry* geom0, const geom::Geometry* geom1);
    std::unique_ptr<geom::Geometry> unionBuffer(const geom::Geometry* geom0, const geom::Geometry* geom1);
    bool isBorderSegmentsSame(const geom::Geometry* result, const geom::Envelope& env);
    bool isEqual(std::vector<geom::LineSegment>& segs0, std::vector<geom::LineSegment>& segs1);
    std::vector<geom::LineSegment> extractBorderSegments(const geom::Geometry* geom0, const geom::Geometry* geom1, const geom::Envelope& env);
    void extractBorderSegments(const geom::Geometry* geom, const geom::Envelope& penv, std::vector<geom::LineSegment>& psegs);

};

} // namespace geos::operation::union
} // namespace geos::operation
} // namespace geos

#endif