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
    virtual ~QwtPlotRescaler();
 
    // 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;
    class PrivateData;
    PrivateData* m_data;
};
 
#endif