Setting the stretch property of a QFont may produce non-linear results

Setting the stretch property of a QFont may produce non-linear results. For example, on X11 and with the Nimbus Sans L font, a string is painted considerably shorter with a stretch of 87 than with a stretch of 88, the difference seems much more than 1%. The difference between a stretch of 100 (normal) and 99 is much less, and seems to correctly correspond to 1%.