QFontMetricsF::boundingRect(() always returns integer values

The following program prints twice the same line, even though one would expect a rect with floating coordinates from QFontMetricsF:

#include <QtGui>

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

QFont font;
font.setPointSizeF(12.231);
font.pixelSize();
QFontMetricsF fmf(font);
QFontMetrics fm(font);
qDebug() << fmf.boundingRect("ABC");
qDebug() << fm.boundingRect("ABC");

return 0;
}