osrm-backend/Algorithms/DouglasPeucker.h

/*

Copyright (c) 2013, Project OSRM, Dennis Luxen, others
All rights reserved.

Redistribution and use in source and binary forms, with or without modification,
are permitted provided that the following conditions are met:

Redistributions of source code must retain the above copyright notice, this list
of conditions and the following disclaimer.
Redistributions in binary form must reproduce the above copyright notice, this
list of conditions and the following disclaimer in the documentation and/or
other materials provided with the distribution.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
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DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR
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(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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*/

#ifndef DOUGLASPEUCKER_H_
#define DOUGLASPEUCKER_H_

#include "../Util/SimpleLogger.h"

#include <osrm/Coordinate.h>

#include <boost/assert.hpp>
#include <boost/foreach.hpp>

#include <cmath>

#include <limits>
#include <stack>
#include <vector>

/* This class object computes the bitvector of indicating generalized input
 * points according to the (Ramer-)Douglas-Peucker algorithm.
 *
 * Input is vector of pairs. Each pair consists of the point information and a
 * bit indicating if the points is present in the generalization.
 * Note: points may also be pre-selected*/

struct SegmentInformation;

class DouglasPeucker {
private:
    typedef std::pair<std::size_t, std::size_t> PairOfPoints;
    //Stack to simulate the recursion
    std::stack<PairOfPoints> recursion_stack;

    double ComputeDistance(
        const FixedPointCoordinate& point,
        const FixedPointCoordinate& segA,
        const FixedPointCoordinate& segB
    ) const;
public:
    void Run(
        std::vector<SegmentInformation> & input_geometry,
        const unsigned zoom_level
    );

};

#endif /* DOUGLASPEUCKER_H_ */