A 180° rotation results in a TxScale QTransform with negative scaling
factors (x=-1.0 y=-1.0). This is not properly handled by blitter paint
engine yet, so use software rendering fallback in this case.
This rendering issue can be seen when using "-webkit-transform" CSS
property in WebKit with DirectFB QPA platform.
Change-Id: Iee496b6bf0c90ffe36c4235ceaa2c80f296b2ca4
Reviewed-by: Samuel Rødal <samuel.rodal@digia.com>
07ea3cf0b3