qwt_plot_series_data_picker.h

/******************************************************************************
 * Qwt Widget Library
 * Copyright (C) 2024   ChenZongYan <czy.t@163.com>
 *****************************************************************************/
#ifndef QWT_PLOT_SERIES_DATA_PICKER_H
#define QWT_PLOT_SERIES_DATA_PICKER_H
#include <QList>
#include <QPointF>
#include "qwt_canvas_picker.h"
#include "qwt_text.h"
class QwtPlot;
class QwtPlotItem;
 
class QWT_EXPORT QwtPlotSeriesDataPicker : public QwtCanvasPicker
{
    Q_OBJECT
    QWT_DECLARE_PRIVATE(QwtPlotSeriesDataPicker)
public:
    enum PickSeriesMode
    {
        PickYValue,  
        PickNearestPoint  
    };
 
    enum TextPlacement
    {
        TextPlaceAuto,         
        TextFollowOnTop,       
        TextFollowOnBottom,    
        TextFollowMouse,       
        TextOnCanvasTopRight,  
        TextOnCanvasTopLeft,   
        TextOnCanvasBottomRight,  
        TextOnCanvasBottomLeft,   
        TextOnCanvasTopAuto,  
        TextOnCanvasBottomAuto  
    };
 
    enum InterpolationMode
    {
        NoInterpolation,     
        LinearInterpolation  
    };
 
    struct FeaturePoint
    {
        QwtPlotItem* item { nullptr };  
        QPointF feature { 0, 0 };       
        size_t index { 0 };             
    };
 
public:
    explicit QwtPlotSeriesDataPicker(QWidget* canvas);
    ~QwtPlotSeriesDataPicker();
 
    void setPickMode(PickSeriesMode mode);
    PickSeriesMode pickMode() const;
 
    void setTextArea(TextPlacement t);
    TextPlacement textArea() const;
 
    void setInterpolationMode(InterpolationMode mode);
    InterpolationMode interpolationMode() const;
    bool isInterpolation() const;
 
    void setNearestSearchWindowSize(int windowSize);
    int nearestSearchWindowSize() const;
 
    void setEnableDrawFeaturePoint(bool on = true);
    bool isEnableDrawFeaturePoint() const;
 
    void setDrawFeaturePointSize(int px);
    int drawFeaturePointSize() const;
 
    void setTextBackgroundBrush(const QBrush& br);
    QBrush textBackgroundBrush() const;
 
    void setTextAlignment(Qt::Alignment al);
    Qt::Alignment textAlignment() const;
 
    // 是否显示x值
    void setEnableShowXValue(bool on);
    bool isEnableShowXValue() const;
 
    // 设置trackerRect在TextFollowMouse模式下的偏移量
    void setTextTrackerOffset(const QPoint& offset);
    QPoint textTrackerOffset() const;
 
    // 顶部矩形文字
    QwtText trackerText(const QPoint& pos) const override;
 
    // 让矩形在最顶部
    QRect trackerRect(const QFont& f) const override;
 
    // 绘制rubberband
    virtual void drawRubberBand(QPainter* painter) const override;
 
    // 手动设置位置
    virtual void setTrackerPosition(const QPoint& pos) override;
 
protected:
    // 获取绘图区域屏幕坐标pos上，的所有可拾取的y值,返回获取的个数
    virtual int pickYValue(const QwtPlot* p, const QPoint& pos, bool interpolate = false);
    // 获取绘图区域屏幕坐标pos上，可拾取的最近的一个点，(基于窗口实现快速索引)
    virtual int pickNearestPoint(const QwtPlot* plot, const QPoint& pos, int windowSize = -5);
private Q_SLOTS:
    // item删除的槽，用于更新记录
    void onPlotItemDetached(QwtPlotItem* item, bool on);
    void onParasitePlotAttached(QwtPlot* parasiteplot, bool on);
 
protected:
    // 生成一个item的文字内容
    virtual QString valueString(const QList< FeaturePoint >& fps) const;
    // 绘制特征点
    virtual void drawFeaturePoint(QPainter* painter, const QwtPlot* plot, const QwtPlotItem* item, const QPointF& itemPoint) const;
    // 鼠标移动
    virtual void move(const QPoint& pos) override;
    // 格式化为坐标轴对应的内容，针对时间轴，value是一个大浮点数，用户需要看到的是2024-10-01这样的数字
    QString formatAxisValue(double value, int axisId, QwtPlot* plot) const;
 
private:
    // 绘制特征点，所谓特征点就是捕获到的点
    void drawAllFeaturePoints(QPainter* painter) const;
    // 更新特征点
    void updateFeaturePoint(const QPoint& pos);
    //
    QRect ensureRectInBounds(const QRect& rect, const QRect& bounds) const;
};
 
#endif  // QWT_PLOT_SERIES_DATA_PICKER_H