qwt_plot_rescaler.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_PLOT_RESCALER_H
#define QWT_PLOT_RESCALER_H
 
#include "qwt_global.h"
#include "qwt_plot.h"
 
#include <qobject.h>
 
class QwtPlot;
class QwtInterval;
class QResizeEvent;
 
class QWT_EXPORT QwtPlotRescaler : public QObject
{
    Q_OBJECT
 
public:
    enum RescalePolicy
    {
        Fixed,
 
        Expanding,
 
        Fitting
    };
 
    enum ExpandingDirection
    {
        ExpandUp,
 
        ExpandDown,
 
        ExpandBoth
    };
 
    // Constructs a rescaler for the given canvas with specified reference axis and policy
    explicit QwtPlotRescaler(QWidget* canvas, QwtAxisId referenceAxis = QwtAxis::XBottom, RescalePolicy = Expanding);
 
    // Destructs the rescaler
    ~QwtPlotRescaler() override;
 
    // Enable or disable the rescaler
    void setEnabled(bool);
    // Check if the rescaler is enabled
    bool isEnabled() const;
 
    // Set the rescale policy
    void setRescalePolicy(RescalePolicy);
    // Get the rescale policy
    RescalePolicy rescalePolicy() const;
 
    // Set the expanding direction for all axes
    void setExpandingDirection(ExpandingDirection);
    // Set the expanding direction for a specific axis
    void setExpandingDirection(QwtAxisId, ExpandingDirection);
    // Get the expanding direction for a specific axis
    ExpandingDirection expandingDirection(QwtAxisId) const;
 
    // Set the reference axis
    void setReferenceAxis(QwtAxisId);
    // Get the reference axis
    QwtAxisId referenceAxis() const;
 
    // Set the aspect ratio for all axes
    void setAspectRatio(double ratio);
    // Set the aspect ratio for a specific axis
    void setAspectRatio(QwtAxisId, double ratio);
    // Get the aspect ratio for a specific axis
    double aspectRatio(QwtAxisId) const;
 
    // Set the interval hint for a specific axis
    void setIntervalHint(QwtAxisId, const QwtInterval&);
    // Get the interval hint for a specific axis
    QwtInterval intervalHint(QwtAxisId) const;
 
    // Get the canvas widget
    QWidget* canvas();
    // Get the canvas widget (const version)
    const QWidget* canvas() const;
 
    // Get the plot widget
    QwtPlot* plot();
    // Get the plot widget (const version)
    const QwtPlot* plot() const;
 
    // Event filter for the plot canvas
    virtual bool eventFilter(QObject*, QEvent*) override;
 
    // Rescale the plot axes
    void rescale() const;
 
protected:
    // Handle canvas resize events
    virtual void canvasResizeEvent(QResizeEvent*);
 
    // Rescale the axes with old and new sizes
    virtual void rescale(const QSize& oldSize, const QSize& newSize) const;
    // Expand a scale interval
    virtual QwtInterval expandScale(QwtAxisId, const QSize& oldSize, const QSize& newSize) const;
 
    // Sync a scale to the reference axis
    virtual QwtInterval syncScale(QwtAxisId, const QwtInterval& reference, const QSize& size) const;
 
    // Update the axes scales
    virtual void updateScales(QwtInterval intervals[ QwtAxis::AxisPositions ]) const;
 
    // Get the orientation of an axis
    Qt::Orientation orientation(QwtAxisId) const;
    // Get the normalized interval of an axis
    QwtInterval interval(QwtAxisId) const;
    // Expand an interval by the specified width
    QwtInterval expandInterval(const QwtInterval&, double width, ExpandingDirection) const;
 
private:
    // Calculate the pixel distance for an axis
    double pixelDist(QwtAxisId, const QSize&) const;
 
    class AxisData;
    QWT_DECLARE_PRIVATE(QwtPlotRescaler)
};
 
#endif