EVOLUTION-MANAGER

Edit File: GeometryPrecisionReducer.h

/**********************************************************************
 *
 * GEOS - Geometry Engine Open Source
 * http://geos.osgeo.org
 *
 * Copyright (C) 2012 Sandro Santilli <strk@keybit.net>
 *
 * 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: precision/GeometryPrecisionReducer.cpp rev. 1.10 (JTS-1.7)
 *
 **********************************************************************/

#ifndef GEOS_PRECISION_GEOMETRYPRECISIONREDUCER_H
#define GEOS_PRECISION_GEOMETRYPRECISIONREDUCER_H

#include <geos/export.h>
#include <memory> // for auto_ptr

// Forward declarations
namespace geos {
  namespace geom { 
    class PrecisionModel;
    class GeometryFactory;
    class Geometry;
  }
}

namespace geos {
namespace precision { // geos.precision

/** \brief
 * Reduces the precision of a {@link Geometry}
 * according to the supplied {@link PrecisionModel}, 
 * ensuring that the result is topologically valid.
 */
class GEOS_DLL GeometryPrecisionReducer {

private:

// Externally owned
  const geom::GeometryFactory *newFactory;

const geom::PrecisionModel &targetPM;

bool removeCollapsed;

bool isPointwise;

std::auto_ptr<geom::Geometry> reducePointwise( const geom::Geometry& geom );

std::auto_ptr<geom::Geometry> fixPolygonalTopology(
                                                 const geom::Geometry& geom );

std::auto_ptr<geom::GeometryFactory> createFactory(
                                          const geom::GeometryFactory& oldGF,
                                          const geom::PrecisionModel& newPM );

GeometryPrecisionReducer(GeometryPrecisionReducer const&); /*= delete*/
  GeometryPrecisionReducer& operator=(GeometryPrecisionReducer const&); /*= delete*/

public:

/**
   * Convenience method for doing precision reduction
   * on a single geometry,
   * with collapses removed
   * and keeping the geometry precision model the same,
   * and preserving polygonal topology.
   *
   * @param g the geometry to reduce
   * @param precModel the precision model to use
   * @return the reduced geometry
   */
  static std::auto_ptr<geom::Geometry> reduce(
                                const geom::Geometry &g,
                                const geom::PrecisionModel &precModel )
  {
    GeometryPrecisionReducer reducer(precModel);
    return reducer.reduce(g);
  }

/**
   * Convenience method for doing precision reduction
   * on a single geometry,
   * with collapses removed
   * and keeping the geometry precision model the same,
   * but NOT preserving valid polygonal topology.
   *
   * @param g the geometry to reduce
   * @param precModel the precision model to use
   * @return the reduced geometry
   */
  static std::auto_ptr<geom::Geometry> reducePointwise(
                                const geom::Geometry &g,
                                const geom::PrecisionModel &precModel )
  {
    GeometryPrecisionReducer reducer(precModel);
    reducer.setPointwise(true);
    return reducer.reduce(g);
  }

GeometryPrecisionReducer(const geom::PrecisionModel &pm)
      :
      newFactory(0),
      targetPM(pm),
      removeCollapsed(true),
      isPointwise(false)
  {}

/**
   * \brief
   * Create a reducer that will change the precision model of the
   * new reduced Geometry
   *
   * @param gf the factory for the created Geometry.
   *           Its PrecisionModel will be used for the reduction.
   *           NOTE: ownership left to caller must be kept alive for
   *           the whole lifetime of the returned Geometry.
   */
  GeometryPrecisionReducer(const geom::GeometryFactory &gf);

/**
   * Sets whether the reduction will result in collapsed components
   * being removed completely, or simply being collapsed to an (invalid)
   * Geometry of the same type.
   *
   * @param remove if <code>true</code> collapsed components will be removed
   */
  void setRemoveCollapsedComponents(bool remove) {
    removeCollapsed = remove;
  }

/** \brief
   * Sets whether the precision reduction will be done
   * in pointwise fashion only.
   *
   * Pointwise precision reduction reduces the precision
   * of the individual coordinates only, but does
   * not attempt to recreate valid topology.
   * This is only relevant for geometries containing polygonal components.
   *
   * @param pointwise if reduction should be done pointwise only
   */
  void setPointwise(bool pointwise)
  {
    isPointwise = pointwise;
  }

std::auto_ptr<geom::Geometry> reduce(const geom::Geometry& geom);

};

} // namespace geos.precision
} // namespace geos

#endif // GEOS_PRECISION_GEOMETRYPRECISIONREDUCER_H