qwt_scale_engine.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_ENGINE_H
#define QWT_SCALE_ENGINE_H

#include "qwt_global.h"
#include "qwt_scale_div.h"
#include "qwt_interval.h"

class QwtTransform;

class QWT_EXPORT QwtScaleArithmetic
{
public:
    static double ceilEps( double value, double intervalSize );
    static double floorEps( double value, double intervalSize );

    static double divideEps( double interval, double steps );

    static double divideInterval( double interval, 
        int numSteps, uint base );
};

class QWT_EXPORT QwtScaleEngine
{
public:
    enum Attribute
    {
        NoAttribute = 0x00,

        IncludeReference = 0x01,

        Symmetric = 0x02,

        Floating = 0x04,

        Inverted = 0x08
    };

    typedef QFlags<Attribute> Attributes;

    explicit QwtScaleEngine( uint base = 10 );
    virtual ~QwtScaleEngine();

    void setBase( uint base );
    uint base() const;

    void setAttribute( Attribute, bool on = true );
    bool testAttribute( Attribute ) const;

    void setAttributes( Attributes );
    Attributes attributes() const;

    void setReference( double reference );
    double reference() const;

    void setMargins( double lower, double upper );
    double lowerMargin() const;
    double upperMargin() const;

    virtual void autoScale( int maxNumSteps,
        double &x1, double &x2, double &stepSize ) const = 0;

    virtual QwtScaleDiv divideScale( double x1, double x2,
        int maxMajorSteps, int maxMinorSteps,
        double stepSize = 0.0 ) const = 0;

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

protected:
    bool contains( const QwtInterval &, double val ) const;
    QList<double> strip( const QList<double>&, const QwtInterval & ) const;

    double divideInterval( double interval, int numSteps ) const;

    QwtInterval buildInterval( double v ) const;

private:
    class PrivateData;
    PrivateData *d_data;
};

class QWT_EXPORT QwtLinearScaleEngine: public QwtScaleEngine
{
public:
    QwtLinearScaleEngine( uint base = 10 );
    virtual ~QwtLinearScaleEngine();

    virtual void autoScale( int maxSteps,
        double &x1, double &x2, double &stepSize ) const;

    virtual QwtScaleDiv divideScale( double x1, double x2,
        int numMajorSteps, int numMinorSteps,
                                     double stepSize = 0.0 ) const;


protected:
    QwtInterval align( const QwtInterval&, double stepSize ) const;

    void buildTicks(
        const QwtInterval &, double stepSize, int maxMinSteps,
        QList<double> ticks[QwtScaleDiv::NTickTypes] ) const;

    QList<double> buildMajorTicks(
        const QwtInterval &interval, double stepSize ) const;

    void buildMinorTicks( const QList<double>& majorTicks,
        int maxMinorSteps, double stepSize,
        QList<double> &minorTicks, QList<double> &mediumTicks ) const;
};

class QWT_EXPORT QwtLogScaleEngine: public QwtScaleEngine
{
public:
    QwtLogScaleEngine( uint base = 10 );
    virtual ~QwtLogScaleEngine();

    virtual void autoScale( int maxSteps,
        double &x1, double &x2, double &stepSize ) const;

    virtual QwtScaleDiv divideScale( double x1, double x2,
        int numMajorSteps, int numMinorSteps,
        double stepSize = 0.0 ) const;

protected:
    QwtInterval align( const QwtInterval&, double stepSize ) const;

    void buildTicks(
        const QwtInterval &, double stepSize, int maxMinSteps,
        QList<double> ticks[QwtScaleDiv::NTickTypes] ) const;

    QList<double> buildMajorTicks(
        const QwtInterval &interval, double stepSize ) const;

    void buildMinorTicks( const QList<double>& majorTicks,
        int maxMinorSteps, double stepSize,
        QList<double> &minorTicks, QList<double> &mediumTicks ) const;
};

Q_DECLARE_OPERATORS_FOR_FLAGS( QwtScaleEngine::Attributes )

#endif