Weston: DIfferent background image on each output

[Pekka Paalanen]

On Fri, 16 Apr 2021 13:29:59 +0000
"Sebert, Holger.ext" <Holger.Sebert.ext at karlstorz.com> wrote:

> Hi,
> 
> in another thread I asked if it is possible to selectively enable or
> disable different connectors (HDMI, DisplayPort, etc.) in Weston. Since
> this is not possible (thanks for the answers, though!), I am thinking of 
> another solution. --
> 
> Suppose there are multiple monitors connected and Weston configures an
> independent desktop for each. Note that it may also happen that the
> user connects one and the same monitor on multiple connectors (e.g.
> both HDMI and DisplayPort). I need to avoid showing an empty desktop to
> the user.
> 
> So, my first question is: How do I decide or control on which desktop
> my application will pop up? (It's a Qt application that is started
> in /etc/init.d on boot).

Hi,

programmatically from the app? I do not recall there being any Wayland
protocol extension for that.

Weston (desktop-shell plugin, really) picks a position (random),
possibly on the output which contains the pointer (if you have a
pointer).

> I would like to show a message (for example in the form of a
> background-image) on all desktops on which my application is NOT shown
> telling the user to check or switch monitor inputs.
> 
> I am thinking of scanning /sys/class/drm for connected outputs and
> creating a suitable weston.ini in a start-up script. For this, however,
> Weston needs to support different background images on different
> outputs.

Different backgrounds feature is not implemented at this time.

> Is this possible? Does it make sense?

It feels very much like you are trying to bend Weston into doing
something that was never implemented yet, then trying to work around
that by hitting more features that were never implemented.

Weston is a very unfriendly compositor for normal desktop use, lacking
almost all the configurability and UI that one could expect from a
desktop. Maybe a different Wayland compositor would suit you better?
The wlroots-based Sway perhaps?

Or, you could explain what you are *actually* trying to achieve in the
first place, and people might be able to recommend something.

If you need particular behaviour like you have asked for, with Weston
you would have to modify the code to implement them. For example, the
output enabling logic and configuration is in the frontend right now,
in compositor/main.c.


Thanks,
pq
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