HullTriangulation.h

/**********************************************************************
 *
 * GEOS - Geometry Engine Open Source
 * http://geos.osgeo.org
 *
 * Copyright (C) 2021 Paul Ramsey <pramsey@cleverelephant.ca>
 *
 * 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.
 *
 **********************************************************************/
 
#pragma once
 
#include <geos/algorithm/hull/HullTri.h>
#include <geos/triangulate/tri/TriList.h>
#include <geos/triangulate/quadedge/TriangleVisitor.h>
 
 
namespace geos {
namespace geom {
class Geometry;
class GeometryFactory;
class Coordinate;
}
namespace triangulate {
namespace quadedge {
class QuadEdge;
class QuadEdgeSubdivision;
}
}
}
 
namespace geos {
namespace algorithm { // geos::algorithm
namespace hull {      // geos::algorithm::hull
 
 
class HullTriangulation
{
    using Geometry = geos::geom::Geometry;
    using GeometryFactory = geos::geom::GeometryFactory;
    using Coordinate = geos::geom::Coordinate;
    template<typename TriType>
    using TriList = geos::triangulate::tri::TriList<TriType>;
    using QuadEdge = geos::triangulate::quadedge::QuadEdge;
    using QuadEdgeSubdivision = geos::triangulate::quadedge::QuadEdgeSubdivision;
    using TriangleVisitor = geos::triangulate::quadedge::TriangleVisitor;
 
private:
 
    static void toTris(
        QuadEdgeSubdivision& subdiv,
        TriList<HullTri>& triList);

    static geom::CoordinateSequence traceBoundary(
        TriList<HullTri>& triList);
 
    static HullTri* findBorderTri(
        TriList<HullTri>& triList);
 
 
 
public:
 
    HullTriangulation() {};
 
    static void createDelaunayTriangulation(
        const Geometry* geom,
        TriList<HullTri>& triList);

    static std::unique_ptr<Geometry> traceBoundaryPolygon(
        TriList<HullTri>& triList,
        const GeometryFactory* factory);
 
    static HullTri* nextBorderTri(HullTri* triStart);

    static std::unique_ptr<Geometry> geomunion(
        TriList<HullTri>& triList,
        const GeometryFactory* factory);
 
 
    class HullTriVisitor : public TriangleVisitor
    {
 
        private:
 
            TriList<HullTri>& triList;
 
        public:
 
            HullTriVisitor(TriList<HullTri>& p_triList)
                : triList(p_triList)
                {};
 
            void visit(std::array<QuadEdge*, 3>& triEdges) override;
 
    }; // HullTriVisitor
 
 
}; // HullTriangulation
 
 
 
} // geos::algorithm::hull
} // geos::algorithm
} // geos