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_double_interval.h"

class QwtScaleTransformation;

class QWT_EXPORT QwtScaleArithmetic
{
public:
    static int compareEps(
        double value1, double value2, double intervalSize);

    static double ceilEps(double value, double intervalSize);
    static double floorEps(double value, double intervalSize);

    static double divideEps(double interval, double steps);

    static double ceil125(double x);
    static double floor125(double x);
};

class QWT_EXPORT QwtScaleEngine
{
public:
    enum Attribute
    {
        NoAttribute = 0,
        IncludeReference = 1, 
        Symmetric = 2, 
        Floating = 4,
        Inverted = 8 
    };

    explicit QwtScaleEngine();
    virtual ~QwtScaleEngine();

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

    void setAttributes(int);
    int 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 maxMajSteps, int maxMinSteps, 
        double stepSize = 0.0) const = 0;

    virtual QwtScaleTransformation *transformation() const = 0;

protected:
    bool contains(const QwtDoubleInterval &, double val) const;
    QwtValueList strip(const QwtValueList&, const QwtDoubleInterval &) const;
    double divideInterval(double interval, int numSteps) const;

    QwtDoubleInterval buildInterval(double v) const;

private:
    class PrivateData;
    PrivateData *d_data;
};

class QWT_EXPORT QwtLinearScaleEngine: public QwtScaleEngine
{
public:
    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;

    virtual QwtScaleTransformation *transformation() const;

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

private:
    void buildTicks(
        const QwtDoubleInterval &, double stepSize, int maxMinSteps,
        QwtValueList ticks[QwtScaleDiv::NTickTypes]) const;

    void buildMinorTicks(
        const QwtValueList& majorTicks,
        int maxMinMark, double step,
        QwtValueList &, QwtValueList &) const;

    QwtValueList buildMajorTicks(
        const QwtDoubleInterval &interval, double stepSize) const;
};

class QWT_EXPORT QwtLog10ScaleEngine: public QwtScaleEngine
{
public:
    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;

    virtual QwtScaleTransformation *transformation() const;

protected:
    QwtDoubleInterval log10(const QwtDoubleInterval&) const;
    QwtDoubleInterval pow10(const QwtDoubleInterval&) const;

private:
    QwtDoubleInterval align(const QwtDoubleInterval&,
        double stepSize) const;

    void buildTicks(
        const QwtDoubleInterval &, double stepSize, int maxMinSteps,
        QwtValueList ticks[QwtScaleDiv::NTickTypes]) const;

    QwtValueList buildMinorTicks(
        const QwtValueList& majorTicks,
        int maxMinMark, double step) const;

    QwtValueList buildMajorTicks(
        const QwtDoubleInterval &interval, double stepSize) const;
};

#endif