EVOLUTION-MANAGER

Edit File: 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

/// A dynamic list of the vertices in a constructed offset curve.
//
/// Automatically removes close vertices
/// which are closer than a given tolerance.
///
/// @author Martin Davis
///
class OffsetSegmentString 
{

private:

geom::CoordinateArraySequence* ptList;

const geom::PrecisionModel* precisionModel;
  
	/** \brief
	 * The distance below which two adjacent points on the curve 
	 * are considered to be coincident.
	 *
	 * This is chosen to be a small fraction of the offset distance.
	 */
	double minimumVertexDistance;

/** \brief
	 * Tests whether the given point is redundant relative to the previous
	 * point in the list (up to tolerance)
	 * 
	 * @param pt
	 * @return true if the point is redundant
	 */
	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]);
      }
    }
  }
	
	/// Check that points are a ring
	//
	/// add the startpoint again if they are not
	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);
	}

/// Get coordinates by taking ownership of them
	//
	/// After this call, the coordinates reference in
	/// this object are dropped. Calling twice will
	/// segfault...
	///
	/// FIXME: refactor memory management of this
	///
	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