DYT/Tool/OpenSceneGraph-3.6.5/include/geos/linearref/LengthLocationMap.h

/**********************************************************************
 *
 * GEOS - Geometry Engine Open Source
 * http://geos.osgeo.org
 *
 * Copyright (C) 2011 Sandro Santilli <strk@kbt.io>
 * Copyright (C) 2005-2006 Refractions Research Inc.
 * Copyright (C) 2001-2002 Vivid Solutions 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: linearref/LengthLocationMap.java r463
 *
 **********************************************************************/

#pragma once

#include <geos/geom/Coordinate.h>
#include <geos/geom/Geometry.h>
#include <geos/linearref/LinearLocation.h>

namespace geos {
namespace linearref { // geos::linearref

/** \brief
 * Computes the LinearLocation for a given length along a linear
 * [Geometry](@ref geom::Geometry).
 *
 * Negative lengths are measured in reverse from end of the linear geometry.
 * Out-of-range values are clamped.
 */
class LengthLocationMap {


private:
    const geom::Geometry* linearGeom;

    LinearLocation getLocationForward(double length) const;

    LinearLocation resolveHigher(const LinearLocation& loc) const;

public:

    // TODO: cache computed cumulative length for each vertex
    // TODO: support user-defined measures
    // TODO: support measure index for fast mapping to a location

    /**
     * \brief
     * Computes the LinearLocation for a
     * given length along a linear [Geometry](@ref geom::Geometry).
     *
     * @param linearGeom the linear geometry to use
     * @param length the length index of the location
     * @return the LinearLocation for the length
     */
    static LinearLocation
    getLocation(const geom::Geometry* linearGeom, double length)
    {
        LengthLocationMap locater(linearGeom);
        return locater.getLocation(length);
    }

    /**
     * \brief
     * Computes the LinearLocation for a
     * given length along a linear [Geometry].
     *
     * @param linearGeom the linear geometry to use
     * @param length the length index of the location
     * @param resolveLower if `true` lengths are resolved to the
     *                     lowest possible index
     * @return the LinearLocation for the length
     */
    static LinearLocation
    getLocation(const geom::Geometry* linearGeom, double length, bool resolveLower)
    {
        LengthLocationMap locater(linearGeom);
        return locater.getLocation(length, resolveLower);
    }

    /**
     * Computes the length for a given LinearLocation
     * on a linear [Geometry](@ref geom::Geometry).
     *
     * @param linearGeom the linear geometry to use
     * @param loc the LinearLocation index of the location
     * @return the length for the LinearLocation
     */
    static double getLength(const geom::Geometry* linearGeom, const LinearLocation& loc);

    LengthLocationMap(const geom::Geometry* linearGeom);

    /**
     * \brief
     * Compute the LinearLocation corresponding to a length.
     *
     * Negative lengths are measured in reverse from end of the linear geometry.
     * Out-of-range values are clamped.
     * Ambiguous indexes are resolved to the lowest possible location value,
     * depending on the value of `resolveLower`.
     *
     * @param length the length index
     * @param resolveLower if `true` lengths are resolved to the
     *                     lowest possible index
     * @return the corresponding LinearLocation
     */
    LinearLocation getLocation(double length, bool resolveLower) const;

    /**
     * \brief
     * Compute the LinearLocation corresponding to a length.
     *
     * Negative lengths are measured in reverse from end of the linear geometry.
     * Out-of-range values are clamped.
     * Ambiguous indexes are resolved to the lowest possible location value.
     *
     * @param length the length index
     * @return the corresponding LinearLocation
     */
    LinearLocation getLocation(double length) const;

    double getLength(const LinearLocation& loc) const;

};

} // geos.linearref
} // geos