Re: no clipping between sibling widgets in GTK on Quartz

[Paul Davis <paul linuxaudiosystems com>]

On Thu, Jul 9, 2009 at 6:43 PM, Ken Cheetham<cheetham franz com> wrote:
>
> Hello -- I'm having a problem that's specific to GTK on Quartz for the
> Mac (GTK-OSX), in case anyone has knowledge of that port.

Your assessment is correct, and as far I understand it (which is
pretty far) it is not correctable in any sane way.

The documentation for NSWindow and NSView, the Cocoa/Quartz classes
make it clear that
the basic drawing model in Quartz does not support clipping like this.

> Our windowing system doesn't use GTK's preferred "packing" model, where
> sibling widgets are arranged side-by-side without overlapping each
> other.  Our system was designed long ago on the model where windows are
> placed explicitly at arbitrary positions, often with overlap between
> siblings.  So we use the GtkFixed class for our generic windows.  We
> also call gtk_fixed_set_has_window on each one, passing TRUE, which on X
> causes each GtkFixed widget to use a real X window, and I believe that
> it's the underlying X window system that's doing the clipping between
> the sibling X windows.

That is correct, and will never work on Quartz (at least not without a
huge amount of disgusting hackery). Apple specifically warn against
using this kind of design.

--p