When creating a QImage, then QPainter(&image), setting painter.setLayoutDirection(Qt::RightToLeft) isn't taken into account (even if painter.layoutDirection then returns Qt::RightToLeft) because when calling painter.drawText, the direction is still left to right.

I'm not sure if it exists any restriction that would explain why it doesn't work in my case, but the documentation doesn't mention anything special (unless I missed something).