qwt_spline_parametrization.h

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/* -*- 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_SPLINE_PARAMETRIZATION_H
#define QWT_SPLINE_PARAMETRIZATION_H 1

#include "qwt_global.h"
#include <qmath.h>
#include <qpoint.h>

class QWT_EXPORT QwtSplineParametrization
{
public:
    enum Type
    {
        ParameterX,

        ParameterY,

        ParameterUniform,

        ParameterChordal,

        ParameterCentripetal,


        ParameterManhattan
    };

    explicit QwtSplineParametrization( int type );
    virtual ~QwtSplineParametrization();

    int type() const;

    virtual double valueIncrement( const QPointF &, const QPointF & ) const;
    
    static double valueIncrementX( const QPointF &, const QPointF & );
    static double valueIncrementY( const QPointF &, const QPointF & );
    static double valueIncrementUniform( const QPointF &, const QPointF & );
    static double valueIncrementChordal( const QPointF &, const QPointF & );
    static double valueIncrementCentripetal( const QPointF &, const QPointF & );
    static double valueIncrementManhattan( const QPointF &, const QPointF & );

private:
    const int d_type;
};

inline double QwtSplineParametrization::valueIncrementX( 
    const QPointF &point1, const QPointF &point2 ) 
{
    return point2.x() - point1.x();
}

inline double QwtSplineParametrization::valueIncrementY(
    const QPointF &point1, const QPointF &point2 )
{
    return point2.y() - point1.y();
}

inline double QwtSplineParametrization::valueIncrementUniform(
    const QPointF &point1, const QPointF &point2 )
{
    Q_UNUSED( point1 )
    Q_UNUSED( point2 )

    return 1.0;
}

inline double QwtSplineParametrization::valueIncrementChordal( 
    const QPointF &point1, const QPointF &point2 ) 
{
    const double dx = point2.x() - point1.x();
    const double dy = point2.y() - point1.y();

    return qSqrt( dx * dx + dy * dy );
}

inline double QwtSplineParametrization::valueIncrementCentripetal(
    const QPointF &point1, const QPointF &point2 )
{
    return qSqrt( valueIncrementChordal( point1, point2 ) );
}

inline double QwtSplineParametrization::valueIncrementManhattan(
    const QPointF &point1, const QPointF &point2 )
{
    return qAbs( point2.x() - point1.x() ) + qAbs( point2.y() - point1.y() );
}

#endif