LineBuilder.h

/**********************************************************************
 *
 * GEOS - Geometry Engine Open Source
 * http://geos.osgeo.org
 *
 * Copyright (C) 2020 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/export.h>
 
#include <geos/operation/overlayng/InputGeometry.h>
#include <geos/operation/overlayng/OverlayNG.h>
#include <geos/geom/Location.h>
#include <geos/geom/LineString.h>
 
#include <vector>
 
 
// Forward declarations
namespace geos {
namespace geom {
class GeometryFactory;
class LineString;
}
namespace operation {
namespace overlayng {
class OverlayEdge;
class OverlayGraph;
class OverlayLabel;
class InputGeometry;
}
}
}
 
namespace geos {      // geos.
namespace operation { // geos.operation
namespace overlayng { // geos.operation.overlayng
 
class GEOS_DLL LineBuilder {
 
private:
 
    // Members
    OverlayGraph* graph;
    int opCode;
    const geom::GeometryFactory* geometryFactory;
    bool hasResultArea;
    int8_t inputAreaIndex;
    std::vector<std::unique_ptr<geom::LineString>> lines;
 
    bool isAllowMixedResult = ! OverlayNG::STRICT_MODE_DEFAULT;
 
    bool isAllowCollapseLines = ! OverlayNG::STRICT_MODE_DEFAULT;
 
    void markResultLines();
 
    bool isResultLine(const OverlayLabel* lbl) const;
 
    static geom::Location effectiveLocation(const OverlayLabel* lbl, uint8_t geomIndex);
 
    void addResultLines();
    void addResultLinesMerged();
 
    std::unique_ptr<geom::LineString> toLine(OverlayEdge* edge) const;
 
    void addResultLinesForNodes();
 
    void addResultLinesRings();
 
    std::unique_ptr<geom::LineString> buildLine(OverlayEdge* node);
 
    /*
    * Finds the next edge around a node which forms
    * part of a result line.
    */
    static OverlayEdge* nextLineEdgeUnvisited(OverlayEdge* node) ;
 
    static int degreeOfLines(OverlayEdge* node) ;
 
 
 
public:
 
    LineBuilder(const InputGeometry* inputGeom, OverlayGraph* p_graph, bool p_hasResultArea, int p_opCode, const geom::GeometryFactory* geomFact)
        : graph(p_graph)
        , opCode(p_opCode)
        , geometryFactory(geomFact)
        , hasResultArea(p_hasResultArea)
        , inputAreaIndex((int8_t)inputGeom->getAreaIndex())
        , isAllowMixedResult(! OverlayNG::STRICT_MODE_DEFAULT)
        , isAllowCollapseLines(! OverlayNG::STRICT_MODE_DEFAULT)
        {}
 
    LineBuilder(const LineBuilder&) = delete;
    LineBuilder& operator=(const LineBuilder&) = delete;
 
    std::vector<std::unique_ptr<geom::LineString>> getLines();
 
    void setStrictMode(bool p_isStrictResultMode)
    {
        isAllowCollapseLines = ! p_isStrictResultMode;
        isAllowMixedResult = ! p_isStrictResultMode;
    }
 
};
 
 
} // namespace geos.operation.overlayng
} // namespace geos.operation
} // namespace geos