OffsetSegmentString.h

/**********************************************************************
 *
 * GEOS - Geometry Engine Open Source
 * http://geos.osgeo.org
 *
 * Copyright (C) 2011 Sandro Santilli <strk@kbt.io>
 * Copyright (C) 2007 Refractions Research 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: operation/buffer/OffsetSegmentString.java r378 (JTS-1.12)
 *
 **********************************************************************/
 
#pragma once
 
#include <geos/geom/Coordinate.h> // for inlines
#include <geos/geom/CoordinateSequence.h> // for inlines
#include <geos/geom/PrecisionModel.h> // for inlines
 
#include <vector>
#include <memory>
#include <cassert>
 
namespace geos {
namespace operation { // geos.operation
namespace buffer { // geos.operation.buffer
 
class OffsetSegmentString {
 
private:
 
    geom::CoordinateSequence* ptList;
 
    const geom::PrecisionModel* precisionModel;
 
    double minimumVertexDistance;
 
    bool
    isRedundant(const geom::Coordinate& pt) const
    {
        if(ptList->size() < 1) {
            return false;
        }
        const geom::Coordinate& lastPt = ptList->back();
        double ptDist = pt.distance(lastPt);
        if(ptDist < minimumVertexDistance) {
            return true;
        }
        return false;
    }
 
    OffsetSegmentString(const OffsetSegmentString&) = delete;
    OffsetSegmentString& operator=(const OffsetSegmentString&) = delete;
 
public:
 
    friend std::ostream& operator<< (std::ostream& os, const OffsetSegmentString& node);
 
    OffsetSegmentString()
        :
        ptList(new geom::CoordinateSequence()),
        precisionModel(nullptr),
        minimumVertexDistance(0.0)
    {
    }
 
    ~OffsetSegmentString()
    {
        delete ptList;
    }
 
    void
    reset()
    {
        if(ptList) {
            ptList->clear();
        }
        else {
            ptList = new geom::CoordinateSequence();
        }
 
        precisionModel = nullptr;
        minimumVertexDistance = 0.0;
    }
 
    void
    setPrecisionModel(const geom::PrecisionModel* nPrecisionModel)
    {
        precisionModel = nPrecisionModel;
    }
 
    void
    setMinimumVertexDistance(double nMinVertexDistance)
    {
        minimumVertexDistance = nMinVertexDistance;
    }
 
    void
    addPt(const geom::Coordinate& pt)
    {
        assert(precisionModel);
 
        geom::Coordinate bufPt = pt;
        precisionModel->makePrecise(bufPt);
        // don't add duplicate (or near-duplicate) points
        if(isRedundant(bufPt)) {
            return;
        }
        // we ask to allow repeated as we checked this ourself
        // (JTS uses a vector for ptList, not a CoordinateSequence,
        // we should do the same)
        ptList->add(bufPt, true);
    }
 
    void
    addPts(const geom::CoordinateSequence& pts, bool isForward)
    {
        if(isForward) {
            for(std::size_t i = 0, n = pts.size(); i < n; ++i) {
                addPt(pts[i]);
            }
        }
        else {
            for(std::size_t i = pts.size(); i > 0; --i) {
                addPt(pts[i - 1]);
            }
        }
    }
 
    void
    closeRing()
    {
        if(ptList->size() < 1) {
            return;
        }
        const geom::Coordinate& startPt = ptList->front();
        const geom::Coordinate& lastPt = ptList->back();
        if(startPt.equals(lastPt)) {
            return;
        }
        // we ask to allow repeated as we checked this ourself
        ptList->add(startPt, true);
    }
 
    geom::CoordinateSequence*
    getCoordinates()
    {
        closeRing();
        geom::CoordinateSequence* ret = ptList;
        ptList = nullptr;
        return ret;
    }
 
    inline size_t
    size() const
    {
        return ptList ? ptList->size() : 0 ;
    }
 
};
 
inline std::ostream&
operator<< (std::ostream& os,
            const OffsetSegmentString& lst)
{
    if(lst.ptList) {
        os << *(lst.ptList);
    }
    else {
        os << "empty (consumed?)";
    }
    return os;
}
 
} // namespace geos.operation.buffer
} // namespace geos.operation
} // namespace geos