QPainter::drawGlyphs() paints nothing with YAxis rotation transform

#include <QtGui>

class TestWidget : public QWidget
{
    Q_OBJECT
public:
    TestWidget(QWidget* parent = 0)
        : QWidget(parent)
    {
        resize(400, 400);
    }

    virtual void paintEvent(QPaintEvent*)
    {
        QPainter painter(this);

        QTransform transform;
        transform.translate(100, 100);
        transform.rotate(50, Qt::YAxis);
        painter.setTransform(transform);

        // Reference drawText() in black.
        painter.setPen(Qt::black);
        painter.drawText(QPointF(0, 0), "There should be red text below.");

        // Failing drawGlyphs() in red.
        QTextLayout layout("There should be black text above.");
        layout.beginLayout();
        QTextLine line = layout.createLine();
        layout.endLayout();

        QList<QGlyphs> g = layout.glyphs();
        painter.setPen(Qt::red);
        painter.drawGlyphs(QPointF(0, 0), g.at(0));
    }
};

int main(int c, char** v)
{
    QApplication a(c, v);

    TestWidget tw;
    tw.show();

    return a.exec();
}

#include "test.moc"