qwt_scale_engine.h

/******************************************************************************
 * 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
 *
 * Modified by ChenZongYan in 2024 <czy.t@163.com>
 *   Summary of major modifications (see ChangeLog.md for full history):
 *   1. CMake build system & C++11 throughout.
 *   2. Core panner/ zoomer refactored:
 *        - QwtPanner → QwtCachePanner (pixmap-cache version)
 *        - New real-time QwtPlotPanner derived from QwtPicker.
 *   3. Zoomer supports multi-axis.
 *   4. Parasite-plot framework:
 *        - QwtFigure, QwtPlotParasiteLayout, QwtPlotTransparentCanvas,
 *        - QwtPlotScaleEventDispatcher, built-in pan/zoom on axis.
 *   5. New picker: QwtPlotSeriesDataPicker (works with date axis).
 *   6. Raster & color-map extensions:
 *        - QwtGridRasterData (2-D table + interpolation)
 *        - QwtLinearColorMap::stopColors(), stopPos() API rename.
 *   7. Bar-chart: expose pen/brush control.
 *   8. Amalgamated build: single QwtPlot.h / QwtPlot.cpp pair in src-amalgamate.
 *****************************************************************************/
 
#ifndef QWT_SCALE_ENGINE_H
#define QWT_SCALE_ENGINE_H
 
#include "qwtcore_global.h"
#include "qwt_scale_div.h"
 
class QwtInterval;
class QwtTransform;
 
class QWTCORE_EXPORT QwtScaleArithmetic
{
public:
    static double ceilEps(double value, double intervalSize);
    static double floorEps(double value, double intervalSize);
 
    static double divideEps(double intervalSize, double numSteps);
 
    static double divideInterval(double intervalSize, int numSteps, uint base);
};
 
class QWTCORE_EXPORT QwtScaleEngine
{
public:
    enum Attribute
    {
        NoAttribute = 0x00,
 
        IncludeReference = 0x01,
 
        Symmetric = 0x02,
 
        Floating = 0x04,
 
        Inverted = 0x08
    };
 
    Q_DECLARE_FLAGS(Attributes, Attribute)
 
    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);
    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 value) const;
    QList< double > strip(const QList< double >&, const QwtInterval&) const;
 
    double divideInterval(double intervalSize, int numSteps) const;
 
    QwtInterval buildInterval(double value) const;
 
private:
    QwtScaleEngine(const QwtScaleEngine&)            = delete;
    QwtScaleEngine& operator=(const QwtScaleEngine&) = delete;
 
    QWT_DECLARE_PRIVATE(QwtScaleEngine)
};
 
class QWTCORE_EXPORT QwtLinearScaleEngine : public QwtScaleEngine
{
public:
    explicit QwtLinearScaleEngine(uint base = 10);
    ~QwtLinearScaleEngine() override;
 
    virtual void autoScale(int maxNumSteps, double& x1, double& x2, double& stepSize) const override;
 
    virtual QwtScaleDiv
    divideScale(double x1, double x2, int maxMajorSteps, int maxMinorSteps, double stepSize = 0.0) const override;
 
protected:
    QwtInterval align(const QwtInterval&, double stepSize) const;
 
    void buildTicks(const QwtInterval&, double stepSize, int maxMinorSteps, 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 QWTCORE_EXPORT QwtLogScaleEngine : public QwtScaleEngine
{
public:
    explicit QwtLogScaleEngine(uint base = 10);
    ~QwtLogScaleEngine() override;
 
    virtual void autoScale(int maxNumSteps, double& x1, double& x2, double& stepSize) const override;
 
    virtual QwtScaleDiv
    divideScale(double x1, double x2, int maxMajorSteps, int maxMinorSteps, double stepSize = 0.0) const override;
 
protected:
    QwtInterval align(const QwtInterval&, double stepSize) const;
 
    void buildTicks(const QwtInterval&, double stepSize, int maxMinorSteps, 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