qt QPainter实现24小时时间轴 ，并且可以移动，鼠标按下后可以左右任意移动并且时间也会随之改变，24小时是固定的但是日期不是固定的

以下是一个简单的实现示例，其中使用了QPainter绘制时间轴，并在QWidget上实现了鼠标按下事件来实现拖动：

#include <QtWidgets>

class TimeAxis : public QWidget {
public:
    explicit TimeAxis(QWidget *parent = nullptr)
        : QWidget(parent)
    {
        setFixedSize(600, 50);
        m_startTime = QDateTime::currentDateTime();
        m_endTime = m_startTime.addDays(1);
    }

    void paintEvent(QPaintEvent *) override
    {
        QPainter painter(this);
        painter.setRenderHint(QPainter::Antialiasing);

        // 绘制背景
        painter.fillRect(rect(), Qt::white);

        // 绘制时间刻度
        const int hourWidth = width() / 24;
        for (int hour = 0; hour <= 24; ++hour) {
            const QPoint p1(hour * hourWidth, 0);
            const QPoint p2(hour * hourWidth, height());
            painter.drawLine(p1, p2);

            if (hour == 0 || hour == 24) continue;

            const QString text = QString::number(hour);
            const QRect textRect(hour * hourWidth - 10, height() / 2 - 10, 20, 20);
            painter.drawText(textRect, Qt::AlignCenter, text);
        }

        // 绘制起始时间和结束时间
        const QRect rectStart(0, 0, hourWidth, height());
        const QRect rectEnd(width() - hourWidth, 0, hourWidth, height());
        painter.drawText(rectStart, Qt::AlignCenter, m_startTime.toString("hh:mm"));
        painter.drawText(rectEnd, Qt::AlignCenter, m_endTime.toString("hh:mm"));
    }

    void mousePressEvent(QMouseEvent *event) override
    {
        m_dragging = true;
        m_dragStart = event->globalPos();
        m_startTimeDrag = m_startTime;
        m_endTimeDrag = m_endTime;
    }

    void mouseReleaseEvent(QMouseEvent *) override
    {
        m_dragging = false;
    }

    void mouseMoveEvent(QMouseEvent *event) override
    {
        if (!m_dragging) return;

        const int dx = event->globalX() - m_dragStart.x();

        // 计算拖动后的时间
        const int duration = m_endTimeDrag.toSecsSinceEpoch() - m_startTimeDrag.toSecsSinceEpoch();
        const QDateTime newStartTime = m_startTimeDrag.addSecs(dx * 3600 / width() * 3600);
        const QDateTime newEndTime = newStartTime.addSecs(duration);

        // 检查时间是否超过范围
        if (newStartTime < QDateTime::currentDateTime()) {
            m_startTime = QDateTime::currentDateTime();
            m_endTime = m_startTime.addSecs(duration);
        } else if (newEndTime > QDateTime::currentDateTime().addDays(1)) {
            m_endTime = QDateTime::currentDateTime().addDays(1);
            m_startTime = m_endTime.addSecs(-duration);
        } else {
            m_startTime = newStartTime;
            m_endTime = newEndTime;
        }

        update();
    }

private:
    QDateTime m_startTime;
    QDateTime m_endTime;

    bool m_dragging;
    QPoint m_dragStart;
    QDateTime m_startTimeDrag;
    QDateTime m_endTimeDrag;
};

int main(int argc, char *argv[])
{
    QApplication app(argc, argv);

    TimeAxis widget;
    widget.show();

    return app.exec();
}

在这个示例中，我们使用QDateTime来处理时间变化，并使用QPainter绘制时间轴。在鼠标按下、移动和释放事件中，我们计算拖动后的时间范围，并更新绘制。