/* -*- mode: C++ ; c-file-style: "stroustrup" -*- *****************************
 * Qwt Widget Library
 * Copyright (C) 1997   Josef Wilgen
 * Copyright (C) 2002   Uwe Rathmann
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the Qwt License, Version 1.0
 *****************************************************************************/

#ifndef QWT_WEEDING_CURVE_FITTER_H
#define QWT_WEEDING_CURVE_FITTER_H

#include "qwt_curve_fitter.h"

/*!
  \brief A curve fitter implementing Douglas and Peucker algorithm

  The purpose of the Douglas and Peucker algorithm is that given a 'curve'
  composed of line segments to find a curve not too dissimilar but that
  has fewer points. The algorithm defines 'too dissimilar' based on the
  maximum distance (tolerance) between the original curve and the
  smoothed curve.

  The runtime of the algorithm increases non linear ( worst case O( n*n ) )
  and might be very slow for huge polygons. To avoid performance issues
  it might be useful to split the polygon ( setChunkSize() ) and to run the algorithm
  for these smaller parts. The disadvantage of having no interpolation
  at the borders is for most use cases irrelevant.

  The smoothed curve consists of a subset of the points that defined the
  original curve.

  In opposite to QwtSplineCurveFitter the Douglas and Peucker algorithm reduces
  the number of points. By adjusting the tolerance parameter according to the
  axis scales QwtSplineCurveFitter can be used to implement different
  level of details to speed up painting of curves of many points.
*/
class QWT_EXPORT QwtWeedingCurveFitter: public QwtCurveFitter
{
public:
    explicit QwtWeedingCurveFitter( double tolerance = 1.0 );
    virtual ~QwtWeedingCurveFitter();

    void setTolerance( double );
    double tolerance() const;

    void setChunkSize( uint );
    uint chunkSize() const;

    virtual QPolygonF fitCurve( const QPolygonF & ) const;
    virtual QPainterPath fitCurvePath( const QPolygonF & ) const;

private:
    virtual QPolygonF simplify( const QPolygonF & ) const;

    class Line;

    class PrivateData;
    PrivateData *d_data;
};

#endif
