QML显示界面帧率（FPS）的方法

头文件：fpslabel.h

#ifndef FPSLABEL_H
#define FPSLABEL_H

#include <QQuickPaintedItem>

class FPSLabel : public QQuickPaintedItem
{
   
    Q_OBJECT
    Q_PROPERTY(int value READ value NOTIFY valueChanged)
public:
    explicit FPSLabel(QQuickItem *parent = 0);

    int value() const;

    void paint(QPainter *);

signals:
    void valueChanged(int);

private:
    void refreshFPS();
    int m_value = -1;
    int m_cacheCount = 0;
    QVector<qint64> m_frames;
};

#endif // FPSLABEL_H

源文件：fpslabel.cpp

#include "fpslabel.h"
#include <QPainter>