Ability to set Monitor GPU scaling mode

[matejdro]

Describe the feature

On X11 I can force a monitor to display provided resolution without scaling (just centering) or by only scaling to aspect ration (and letterboxing):

xrandr --output DisplayPort-1 --set "scaling mode" "Center"
xrandr --output DisplayPort-1 --set "scaling mode" "Full aspect"

(https://drmdb.emersion.fr/properties/3233857728/scaling%20mode)

Why would it be beneficial

This property is useful when mirroring to a display that has a different aspect ratio than your main display, for example while giving a presentation or connecting to a TV. But from what I can see, there is no way to do this in Hyprland.

[vaxerski]

would first require support in aquamarine

[Szwagi]

Letterboxing is useful for gaming as well.

I played some competitive games for thousands of hours on a 24.5" 1080p display and it's very difficult to adjust to a 27" display.
For this reason, some monitors come with a built in 24.5" mode that runs letterboxed at 2368x1332.

Currently the best option for this is gamescope, but I couldn't figure out how to make gamescope tear (only in the SDL backend, which is not usable).

I have tried making the game a centered floating window with no borders, but it doesn't tear even if it's the only window on the workspace.