How to set the default/main display

[Zoddo]

With Budgie 10.10, the default display (where the taskbar is displayed) always seems to be the leftmost screen.

wdisplays don't have any settings to specify which screen is the default screen.

Is there a hidden setting to set the main display?

[fossfreedom]

Ad you can gather wayland doesn't have the concept of primary display.

In wdisplays you can hint at the main display by moving the display top-left so that the position is at a 0,0 coordinate. Other monitors can then go around that. But wayland compositors can have their own view of things and this doesn't always work.

[Zoddo]

I see. So let's say I have 3 screens, and my main display is supposed to be the middle screen, there is currently no way to put the taskbar on that middle screen?

Currently, I've found that disconnecting/reconnecting the left screen after starting the session works as a workaround for this limitation, as the taskbar gets moved to the middle screen and isn't moved back to the left screen when reconnecting it.

I will probably try to script turning off/on that left screen if there are no plans to define on which screen the taskbar should appear for now :)

[fossfreedom]

As I mentioned - there is no concept of "primary" in wayland. So any implementation needs to define that with some logic and all areas of the code needs to use that concept of primary.

At the moment looking at the code-base the panel-manager and run-dialog uses the Gdk "primary_monitor" function. So at a minimum these areas need addressing.

We do have a static "WaylandClient" library that has Screen and Monitor logic. We could beef this area up and call stuff from Panel Manager and Run Dialog to say something like "what is the primary monitor" and possibly logic like "oops the primary monitor has changed because the user or some-other event such as the display been disconnected".

Think this will need more thought.

Then there is the "How to define the primary monitor". Logically this should have all been done in the budgie-configurator app which interfaces with budgie-display-services .... but that is now a budgie-11 matter and what we are looking for is a least risk solution for just 10.10.x. I'm interested in a least risk solution since we (ubuntu budgie) are well past feature freeze and asking for multiple components to be updated at the same time is not something I want to even attempt.

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Possible implementation.

1. Have a primary monitor list gsettings array in the budgie-wm schema. The idea here is to define what the primary is ... and any fallbacks. The idea would be - for example - a user who moves a laptop around and maybe connected to multiple different monitors on their travels.
2. Beef up WaylandClient to get a primary monitor ... validate if it exists ... if it doesnt rinse and repeat through the list of fallbacks until there is a valid primary found. And if no valid primary found then just default to something - just a question of what that something is I suppose.
3. Have some-sort of GUI (budgie desktop settings) that allows the user to "click a button" on a list of monitors to set the primary. Save what the user chooses.

I remember Josh mentioned when developing budgie-desktop-services that all "monitors are not equal" - so displaying monitors should have extra info displayed next to each monitor in the list. Given we have "remembered" possible fallbacks - thinking about it, we would need to somehow cache those details somewhere because obtaining extra details for a monitor that is not actually connected is kind of difficult...

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TL;DR; not simple - not beyond the wit of man to plug something together

[fossfreedom]

Currently in git main which will form 10.10.3 in due course I have created an implementation along the lines as discussed.

We will refine this as more eyes see it, so feel free to try out your unstable repo or when 10.10.3 is released. Do feedback

Cheers