1、概述
源码放在文章末尾

该项目实现了可以显示帧率的控件，项目demo演示如下所示：

、
项目部分代码如下所示：

#ifndef FPSITEM_H
#define FPSITEM_H

#include <QQuickItem>

class FpsItem : public QQuickItem
{
    Q_OBJECT

    Q_PROPERTY(int fps READ fps NOTIFY fpsChanged)

public:
    FpsItem(QQuickItem *parent = nullptr);

    int fps() const;

signals:
    void fpsChanged();

private:
    int m_fps = 0;
    int m_frameCount = 0;
};

#endif // FPSITEM_H

#include "fpsitem.h"

#include <QQuickWindow>
#include <QTimer>

FpsItem::FpsItem(QQuickItem *parent)
    : QQuickItem(parent)
{
    QTimer *timer = new QTimer(this);
    connect(timer, &QTimer::timeout, this, [this]{ m_fps = m_frameCount; m_frameCount = 0; emit fpsChanged(); });
    connect(this, &QQuickItem::windowChanged, this, [this]{
        if (window())
            connect(window(), &QQuickWindow::afterRendering, this
                    , [this]{ m_frameCount++; }, Qt::DirectConnection);
    });
    timer->start(1000);
}

int FpsItem::fps() const
{
    return m_fps;
}

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