[Interest] QGraphicsItemGroup with QObject features.

[Dmitrii Volosnykh]

Hello, everyone,

I'd like to have one similar to QGraphicsObject in order to make it
animatable by its properties. First I tried to inherit my group from
QGraphicsObject and QGraphicsItemGroup, but, as you might have
guessed, both of those classes are inherited from QGraphicsItem. So,
I've stuck with numerous ambiguity-related compiler errors. At first
glance, it seems that in both cases making inheritance from
QGraphicsItem virtual would be appropriate (probably, there are some
design feature that prevent from such inheritance).

For now I have obtained animatable group by inheriting it from QObject
instead of QGraphicsObject and trying to mimic implementation of
properties from QGraphicsObject, i.e. I added Q_PROPERTY macros. The
issue with this solution is that I can't make corresponding signals
(for example, scaleChanged() for scale property) be emitted while
animation is performed. I could not figure out how that is done for
QGraphicsObject.

Regards,
Dmitrii.