RenderLayer code

[Lars Knoll]

> Quoting Lars Knoll <lars@trolltech.com>:
> > At the same time we have a performance problem with the layer code I have
> > to
> > look into. Our painting got slower by a factor of about 5 (just
> > estimated).
> > I'll check with the new layer code, but one problem might be that you
> > construct and flatten the ztree on every paint call.
>
> You hadn't integrated the phase checks in paint methods, so everything was
> getting drawn (at least) thrice.

Oopps, thanks for fixing it.

Lars