Bug 499861

Yeah, we removed it at some point in the past. I don't recall the reasons though.

Indeed, this would be very helpful. Even for the same physical setup, it is useful to change between different screen arrangement layouts. As a lecturer, I am regularly working on different sites with slightly differing work desk setups even though they are equipped with monitors of the same type. In the teaching rooms, the setup also changes from site to site (e.g. one or two projections and differing standard resolution, e.g. 1920 x 1080 and 1920 x 1200). To properly exploit the infrastructure with two projections, I use in addition a third external portable USB-C screen attached to my laptop. Depending on the teaching situation, I set the projections up as mirrors of the laptop screen and the USB-C screen or as independent screens (especially when presenting slides). For proper mirroring, I have to manually change the resolution of the laptop screen and USB-C screen from native 1920 x 1200 to 1920 x 1080. Unfortunately, this resolution change is conserved even when moving to a different monitor setup. Therefore, I have to constantly fiddle with the settings in kcm_screen. 

It would be really helpful to be able to explicitly create distinct configurations for a certain monitor setup, which can ideally quickly switched using some configurable hotkey and maybe some CLI interface/DBUS message (to facilitate control from a shell or a streamdeck).

Output position is remembered per setup.

As for why the "remember per setup" option was removed, it caused a huge amount of problems. It was one of the biggest sources of bug reports and reasons that people had to manually fiddle with display settings all the time.

A more specific option for the actually useful parts (which seems to be scale and nothing else?) would be fine.

(In reply to Zamundaaa from comment #3)
> Output position is remembered per setup.
> 
> As for why the "remember per setup" option was removed, it caused a huge
> amount of problems. It was one of the biggest sources of bug reports and
> reasons that people had to manually fiddle with display settings all the
> time.
> 
> A more specific option for the actually useful parts (which seems to be
> scale and nothing else?) would be fine.

As I explained in my comment from 2025-03-06, there are use cases where it is handy if not only the scale but also the screen resolution is saved along with the layout of the different connected screens. As a lecturer, I don't mind to have to set screen layout, resolution, and scale once per room in which I teach. However, it becomes somewhat if the resolution needs to be adjusted over and over again to match the resolution of the external screen.

Maybe, it would help if it were possible to explicitly specify which screen should be the mirror of another screen? This seems to be the way how the screen configuration dialogues in macOS and Windows approached this problem.

I would also like to note that there are use cases where one would like to keep the screens separated, e.g., when presenting slides with a program, which offers a presentation console for the lecturer in addition to the full screen display of the slides. However, once one wants to show something in a web browser or another application, usually the screen layout needs to be adjusted to mirror the screen with the application.

(In reply to Torsten Maehne from comment #4)
> However, it becomes somewhat if the resolution needs to be
> adjusted over and over again to match the resolution of the external screen.
> 
> Maybe, it would help if it were possible to explicitly specify which screen
> should be the mirror of another screen? This seems to be the way how the
> screen configuration dialogues in macOS and Windows approached this problem.
You can explicitly specify which screen should mirror another screen, with the "replica of" combobox in the display settings.
It doesn't require resolutions to match, and while it still has some issues, those should be fixed soon. You can follow bug 481222 about that.

(original reporter)
I insist that I do not need only scale and resolution to be remembered for each setup, but also relative display positions.

Also I share Torsten's concerns as I also give lectures, with possibly different setups. Usually it's just one screen which I keep at its native resolution and scale, since I just use Okular in presentation mode and Okular handles the scale; but one of my amphitheaters has 2 projection screens, which can be nice to project different things at the same time, for instance, my slides, along with a code editor.

And of course, Zamundaa (who posted at the same time as my last comment) is right, which screen is clone of which can now be set from the UI (there was a time when it wasn't available anymore). Alas, this setting too will not be remembered either, as far as I can tell (but I cannot test it now).

Positions, enable/disable, primary/not and replication source are all per setup, they wouldn't make too much sense as a globally saved value.