The QImage inplace mirroring method, failed to handle the middle line
when mirroring both ways (rotate 180). In both other mirroring cases
the middle can be left untouched, but in this case it needs to be
mirrored half way.
To make the logic simpler, double mirroring will now mirror half the
lines instead of half of every line.
Change-Id: Iaa1f1e1c3f7dedfb78891fc93207f6d0c64bcafe
Reviewed-by: Konstantin Ritt <ritt.ks@gmail.com>
Reviewed-by: Gunnar Sletta <gunnar@sletta.org>
f657ecdc5d