Re: Unexpected visual effect under GNOME Shell

[Michael Thayer <michael thayer oracle com>]

We created a test case application for Olivier and he decided it is a
different case after all.  xprop says that the black window is
WM_NAME-ed "mutter guard window".

Regards
Michael

08.02.2018 07:58, Michael Thayer wrote:
> Hello Jonas,
>
> Thank you, that does look like it.  I will tag onto that bug and see
> what comes of it.
>
> Regards
> Michael
>
> 07.02.2018 04:21, Jonas Ådahl wrote:
> > The flashing black rectangle you are seeing could possibly be
> > https://bugzilla.gnome.org/show_bug.cgi?id=767212.
> >
> >
> > Jonas
> >
> > On Tue, Feb 06, 2018 at 04:16:51PM +0100, Michael Thayer wrote:
> > > Hello,
> > >
> > > Wondering if anyone can help us with the following question.  In
> > > VirtualBox we need for various reasons to know what the usable area of
> > > each screen is - that translates as the largest rectangle which fits on
> > > that screen without obscuring any panels or similar.  We find that out
> > > by mapping a maximised window on each screen at start-up and checking
> > > its position and dimensions.  To prevent disturbance to the user we
> > > create the window fully translucent, or if the X server does not support
> > > that we use XShape and leave only a single pixel visible.  On GNOME
> > > Shell Wayland edition (what is the right way to say that?) this
> > > unfortunately flashes a black rectangle up on the screen in the area
> > > which should be translucent.  I assume this is Xwayland-related, but is
> > > there any way to prevent it?
> > >
> > > For a bit of background, creating a maximised window as we do was the
> > > best way we found of getting the information we need.  Qt does not
> > > provide it directly, _NET_WORKAREA is not quite the right thing either
> > > and not all window managers provide usable strut information as some of
> > > them composite panels directly rather than creating windows for them.
> > > We use the area found for a number of things, in particular: adjusting
> > > the size and position of windows restored from previous sessions if the
> > > old positions no longer fit the current layout (especially to prevent
> > > windows appearing off-screen) and correctly placing the toolbar windows
> > > which we use in seamless mode, which we want to span the bottom
> > > (usually) of a given screen, but above any window manager toolbars or
> > > panels.  Of course, the problem is finding something which works, if not
> > > in all window managers, at least for as many popular ones as possible.
> > >
> > > Thanks!
> > > Regards
> > > Michael
> > > -- 
> > > Michael Thayer | VirtualBox engineer
> > > ORACLE Deutschland B.V. & Co. KG | Werkstr. 24 | D-71384 Weinstadt
> > >
> > > ORACLE Deutschland B.V. & Co. KG
> > > Hauptverwaltung: Riesstraße 25, D-80992 München
> > > Registergericht: Amtsgericht München, HRA 95603
> > >
> > > Komplementärin: ORACLE Deutschland Verwaltung B.V.
> > > Hertogswetering 163/167, 3543 AS Utrecht, Niederlande Handelsregister
> > > der Handelskammer Midden-Nederland, Nr. 30143697
> > > Geschäftsführer: Alexander van der Ven, Jan Schultheiss, Val Maher
> > > _______________________________________________
> > > gnome-shell-list mailing list
> > > gnome-shell-list gnome org
> > > https://mail.gnome.org/mailman/listinfo/gnome-shell-list

-- 
Michael Thayer | VirtualBox engineer
ORACLE Deutschland B.V. & Co. KG | Werkstr. 24 | D-71384 Weinstadt

ORACLE Deutschland B.V. & Co. KG
Hauptverwaltung: Riesstraße 25, D-80992 München
Registergericht: Amtsgericht München, HRA 95603

Komplementärin: ORACLE Deutschland Verwaltung B.V.
Hertogswetering 163/167, 3543 AS Utrecht, Niederlande Handelsregister
der Handelskammer Midden-Nederland, Nr. 30143697
Geschäftsführer: Alexander van der Ven, Jan Schultheiss, Val Maher