qwt_scale_map.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_MAP_H
#define QWT_SCALE_MAP_H
 
#include "qwtcore_global.h"
#include "qwt_transform.h"
 
class QPointF;
class QRectF;
 
class QWTCORE_EXPORT QwtScaleMap
{
public:
    QwtScaleMap();
    QwtScaleMap(const QwtScaleMap&);
    QwtScaleMap(QwtScaleMap&&);
 
    ~QwtScaleMap();
 
    QwtScaleMap& operator=(const QwtScaleMap&);
    QwtScaleMap& operator=(QwtScaleMap&&);
 
    void setTransformation(QwtTransform*);
    const QwtTransform* transformation() const;
 
    void setPaintInterval(double p1, double p2);
    void setScaleInterval(double s1, double s2);
 
    double transform(double s) const;
    double invTransform(double p) const;
 
    Q_DECL_CONSTEXPR double p1() const noexcept { return m_p1; }
    Q_DECL_CONSTEXPR double p2() const noexcept { return m_p2; }
 
    Q_DECL_CONSTEXPR double s1() const noexcept { return m_s1; }
    Q_DECL_CONSTEXPR double s2() const noexcept { return m_s2; }
 
    double pDist() const { return qAbs(m_p2 - m_p1); }
    double sDist() const { return qAbs(m_s2 - m_s1); }
 
    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&);
 
    static bool isLinerScale(const QwtScaleMap& sm);
 
    Q_DECL_CONSTEXPR bool isLinear() const noexcept { return m_transform == nullptr; }
 
    Q_DECL_CONSTEXPR bool isInverting() const noexcept { return ((m_p1 < m_p2) != (m_s1 < m_s2)); }
 
    Q_DECL_CONSTEXPR double cnv() const noexcept { return m_cnv; }
 
    Q_DECL_CONSTEXPR double ts1() const noexcept { return m_ts1; }
 
protected:
    void swap(QwtScaleMap& other) noexcept;  // helper
private:
    void updateFactor();
 
    double m_s1 { 0.0 }, m_s2 { 1.0 };  // scale interval boundaries
    double m_p1 { 0.0 }, m_p2 { 1.0 };  // paint device interval boundaries
 
    double m_cnv { 1.0 };  // conversion factor
    double m_ts1 { 0.0 };
 
    QwtTransform* m_transform { nullptr };
};
 
inline double QwtScaleMap::transform(double s) const
{
    if (m_transform)
        s = m_transform->transform(s);
 
    return m_p1 + (s - m_ts1) * m_cnv;
}
 
inline double QwtScaleMap::invTransform(double p) const
{
    double s = m_ts1 + (p - m_p1) / m_cnv;
    if (m_transform)
        s = m_transform->invTransform(s);
 
    return s;
}
 
#ifndef QT_NO_DEBUG_STREAM
QWTCORE_EXPORT QDebug operator<<(QDebug, const QwtScaleMap&);
#endif
 
#endif