qwt_plot_canvas_zoomer.h

/******************************************************************************
 * Qwt Widget Library
 * Copyright (C) 2024   ChenZongYan <czy.t@163.com>
 *****************************************************************************/
#ifndef QWT_PLOT_CANVAS_ZOOMER_H
#define QWT_PLOT_CANVAS_ZOOMER_H
#include "qwt_global.h"
#include "qwt_canvas_picker.h"
#include "qwt_axis_id.h"
#include "qwt_interval.h"
#include <QPointer>
// Qt
class QSizeF;
template< typename T >
class QStack;
// Qwt
class QwtPlot;
 
struct QWT_EXPORT QwtPlotCanvasZoomState
{
public:
    QwtPlotCanvasZoomState();
    QwtPlotCanvasZoomState(QwtPlot* p,
                           const QwtInterval& yLeft,
                           const QwtInterval& yRight,
                           const QwtInterval& xBottom,
                           const QwtInterval& xTop);
    // 从plot获取当前所有坐标轴的状态
    static QwtPlotCanvasZoomState fromPlot(QwtPlot* plot);
 
    // 将状态应用到plot
    void apply() const;
 
    // 判断两个状态是否相等
    bool operator==(const QwtPlotCanvasZoomState& other) const;
    bool operator!=(const QwtPlotCanvasZoomState& other) const;
 
    // 检查状态是否有效
    bool isValid() const;
 
public:
    QPointer< QwtPlot > plot;
    QwtInterval axisInterval[ QwtAxis::AxisPositions ];
};
Q_DECLARE_METATYPE(QwtPlotCanvasZoomState)
 
 
class QWT_EXPORT QwtPlotCanvasZoomer : public QwtCanvasPicker
{
    Q_OBJECT
    QWT_DECLARE_PRIVATE(QwtPlotCanvasZoomer)
public:
    explicit QwtPlotCanvasZoomer(QWidget* canvas, bool doReplot = true);
    virtual ~QwtPlotCanvasZoomer();
 
    // 设置缩放基准状态（当前所有坐标轴的范围），最小缩放范围会基于此基准进行计算
    virtual void setZoomBase(bool doReplot = true);
 
    // 设置是否自动replot,默认为true
    void setAutoReplot(bool on = true);
    bool isAutoReplot() const;
    // 获取基准缩放状态
    QList< QwtPlotCanvasZoomState > zoomBase() const;
    // 获取当前缩放状态
    QList< QwtPlotCanvasZoomState > zoomState() const;
    // zoomer记录的最大的缩放次数，如果超过这个次数，不会再让缩放,-1为不限制次数
    void setMaxStackDepth(int);
    int maxStackDepth() const;
    // 缩放栈
    const QStack< QList< QwtPlotCanvasZoomState > >& zoomStack() const;
 
    uint zoomStateIndex() const;
 
public Q_SLOTS:
    // 通过索引在缩放栈中导航
    virtual void zoom(int offset);
    virtual void appendZoom(const QList< QwtPlotCanvasZoomState >& rect);
Q_SIGNALS:
    void zoomed(const QList< QwtPlotCanvasZoomState >& state);
 
protected:
    virtual void rescale();
 
    virtual void widgetMouseReleaseEvent(QMouseEvent*) QWT_OVERRIDE;
    virtual void widgetKeyPressEvent(QKeyEvent*) QWT_OVERRIDE;
 
    virtual void begin() QWT_OVERRIDE;
    virtual bool end(bool ok = true) QWT_OVERRIDE;
    virtual bool accept(QPolygon&) const QWT_OVERRIDE;
 
private:
    void init(bool doReplot);
 
    // 将画布上的像素矩形转换为四个坐标轴的缩放状态
    QList< QwtPlotCanvasZoomState > canvasRectToZoomStateList(const QRect& pixelRect) const;
    // 将画布上的像素矩形转换为四个坐标轴的缩放状态
    QwtPlotCanvasZoomState canvasRectToZoomState(QwtPlot* plt, const QRect& pixelRect) const;
    // 移动当前缩放状态
    void moveCurrentState(double dx, double dy);
};
 
#endif  // QWTCANVASZOOMER_H