qwt_scale_map.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_SCALE_MAP_H
#define QWT_SCALE_MAP_H

#include "qwt_global.h"
#include "qwt_math.h"
#ifndef QT_NO_DEBUG_STREAM
#include <qdebug.h>
#endif

class QRectF;

class QWT_EXPORT QwtScaleTransformation
{
public:
    enum Type
    {
        Linear,

        Log10,

        Other
    };

    QwtScaleTransformation( Type type );
    virtual ~QwtScaleTransformation();

    virtual double xForm( double s, double s1, double s2,
        double p1, double p2 ) const;
    virtual double invXForm( double p, double p1, double p2,
        double s1, double s2 ) const;

    Type type() const;

    virtual QwtScaleTransformation *copy() const;

private:
    QwtScaleTransformation();
    QwtScaleTransformation &operator=( const QwtScaleTransformation );

    const Type d_type;
};

inline QwtScaleTransformation::Type QwtScaleTransformation::type() const
{
    return d_type;
}

class QWT_EXPORT QwtScaleMap
{
public:
    QwtScaleMap();
    QwtScaleMap( const QwtScaleMap& );

    ~QwtScaleMap();

    QwtScaleMap &operator=( const QwtScaleMap & );

    void setTransformation( QwtScaleTransformation * );
    const QwtScaleTransformation *transformation() const;

    void setPaintInterval( double p1, double p2 );
    void setScaleInterval( double s1, double s2 );

    double transform( double s ) const;
    double invTransform( double p ) const;

    double p1() const;
    double p2() const;

    double s1() const;
    double s2() const;

    double pDist() const;
    double sDist() const;

    QT_STATIC_CONST double LogMin;
    QT_STATIC_CONST double LogMax;

    static QRectF transform( const QwtScaleMap &,
        const QwtScaleMap &, const QRectF & );
    static QRectF invTransform( const QwtScaleMap &,
        const QwtScaleMap &, const QRectF & );

    static QPointF transform( const QwtScaleMap &,
        const QwtScaleMap &, const QPointF & );
    static QPointF invTransform( const QwtScaleMap &,
        const QwtScaleMap &, const QPointF & );

    bool isInverting() const;

private:
    void newFactor();

    double d_s1, d_s2;     // scale interval boundaries
    double d_p1, d_p2;     // paint device interval boundaries

    double d_cnv;       // conversion factor

    QwtScaleTransformation *d_transformation;
};

inline double QwtScaleMap::s1() const
{
    return d_s1;
}

inline double QwtScaleMap::s2() const
{
    return d_s2;
}

inline double QwtScaleMap::p1() const
{
    return d_p1;
}

inline double QwtScaleMap::p2() const
{
    return d_p2;
}

inline double QwtScaleMap::pDist() const
{
    return qAbs( d_p2 - d_p1 );
}

inline double QwtScaleMap::sDist() const
{
    return qAbs( d_s2 - d_s1 );
}

inline double QwtScaleMap::transform( double s ) const
{
    // try to inline code from QwtScaleTransformation

    if ( d_transformation->type() == QwtScaleTransformation::Linear )
        return d_p1 + ( s - d_s1 ) * d_cnv;

    if ( d_transformation->type() == QwtScaleTransformation::Log10 )
        return d_p1 + log( s / d_s1 ) * d_cnv;

    return d_transformation->xForm( s, d_s1, d_s2, d_p1, d_p2 );
}

inline double QwtScaleMap::invTransform( double p ) const
{
    return d_transformation->invXForm( p, d_p1, d_p2, d_s1, d_s2 );
}

inline bool QwtScaleMap::isInverting() const
{
    return ( ( d_p1 < d_p2 ) != ( d_s1 < d_s2 ) );
}

#ifndef QT_NO_DEBUG_STREAM
QWT_EXPORT QDebug operator<<( QDebug, const QwtScaleMap & );
#endif

#endif