OffsetSegmentString.h

/**********************************************************************
 *
 * GEOS - Geometry Engine Open Source
 * http://geos.osgeo.org
 *
 * Copyright (C) 2011 Sandro Santilli <strk@keybit.net>
 * 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)
 *
 **********************************************************************/
 
#ifndef GEOS_OP_BUFFER_OFFSETSEGMENTSTRING_H
#define GEOS_OP_BUFFER_OFFSETSEGMENTSTRING_H
 
#include <geos/geom/Coordinate.h> // for inlines
#include <geos/geom/CoordinateSequence.h> // for inlines
#include <geos/geom/CoordinateArraySequence.h> // for composition
#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::CoordinateArraySequence* 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;
        }
        
 
public:
        
        friend std::ostream& operator<< (std::ostream& os, const OffsetSegmentString& node);
 
        OffsetSegmentString()
                :
                ptList(new geom::CoordinateArraySequence()),
                precisionModel(NULL),
                minimumVertexDistance (0.0)
        {
        }
 
        ~OffsetSegmentString()
        {
                delete ptList;
        }
 
        void reset()
        {
                if ( ptList ) ptList->clear(); 
                else ptList = new geom::CoordinateArraySequence();
 
                precisionModel = NULL;
                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 (size_t i=0, n=pts.size(); i<n; ++i) {
        addPt(pts[i]);
      }
    } else {
      for (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 = 0;
                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
 
 
#endif // ndef GEOS_OP_BUFFER_OFFSETSEGMENTSTRING_H