QFontMetrics::boundingRect(const QString &) to narrow with certain characters in the string

#include <QApplication>
#include <QFontMetrics>
#include <QPainter>
#include <QWidget>

class TestWidget : public QWidget {
public:
    using QWidget::QWidget;

protected:
    void paintEvent(QPaintEvent *event)
    {
        QString text = "🏡☕";
        QPainter painter{ this };
        QFontMetrics metric{ painter.font(), this };
        QRect box = metric.boundingRect(text);
        painter.fillRect(100 + box.x(), 100 + box.y(),
                         box.width(), box.height(),
                         QColor{ "lightgreen" });
        painter.drawText(100, 100, text);
    }
};

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    TestWidget widget;
    widget.show();
    return a.exec();
}