qwt_transform.h

/* -*- 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_TRANSFORM_H
#define QWT_TRANSFORM_H

#include "qwt_global.h"

class QWT_EXPORT QwtTransform
{
public:
    QwtTransform();
    virtual ~QwtTransform();

    virtual double bounded( double value ) const;

    virtual double transform( double value ) const = 0;

    virtual double invTransform( double value ) const = 0;

    virtual QwtTransform *copy() const = 0;
};

class QWT_EXPORT QwtNullTransform: public QwtTransform
{
public:
    QwtNullTransform();
    virtual ~QwtNullTransform();

    virtual double transform( double value ) const;
    virtual double invTransform( double value ) const;

    virtual QwtTransform *copy() const;
};
class QWT_EXPORT QwtLogTransform: public QwtTransform
{   
public:
    QwtLogTransform();
    virtual ~QwtLogTransform();
    
    virtual double transform( double value ) const;
    virtual double invTransform( double value ) const;

    virtual double bounded( double value ) const;

    virtual QwtTransform *copy() const;

#if QT_VERSION >= 0x050400
    static const double LogMin;
    static const double LogMax;
#else
    QT_STATIC_CONST double LogMin;
    QT_STATIC_CONST double LogMax;
#endif
};

class QWT_EXPORT QwtPowerTransform: public QwtTransform
{
public:
    QwtPowerTransform( double exponent );
    virtual ~QwtPowerTransform();

    virtual double transform( double value ) const;
    virtual double invTransform( double value ) const;

    virtual QwtTransform *copy() const;

private:
    const double d_exponent;
};

#endif