Bug 512844

Summary:	Ability to manually scale entire screen on Wayland, like xrandr --scale
Product:	[Plasma] kwin	Reporter:	forestbeasts <forestbeasts>
Component:	wayland-generic	Assignee:	KWin default assignee <kwin-bugs-null>
Status:	RESOLVED NOT A BUG
Severity:	wishlist	CC:	ilikefoss, kde
Priority:	NOR
Version First Reported In:	unspecified
Target Milestone:	---
Platform:	Other
OS:	Linux
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:

Description forestbeasts 2025-12-01 19:02:32 UTC

SUMMARY
On X11, you can scale your entire screen by doing `xrandr --output Whatever --scale NxN`. For instance, 2x2 gives you 2x SSAA, and 0.5x0.5 with --filter nearest (...I think? it's been a while) lets you do integer scaling, e.g. 1080p to a 4K screen with no upscale blurring (like the screen itself would do if you sent it a 1080p signal).

In addition to just being useful if you want to run your desktop at 1080p on a 4K TV or make games run better/get SSAA by pretending you have a smaller/bigger screen (gamescope can handle game usage pretty well honestly), pretending you have a bigger screen than you've got can also be helpful for taking screenshots of really big things like long comment threads that don't fit on your screen.

It's also great if you've got a 640x480 monitor (our CRT can get 120Hz if we push it that low) and want to run a 1280x960 desktop! The display scaling doesn't go _below_ 1.

STEPS TO REPRODUCE
1. Attempt to scale screen.

OBSERVED RESULT
There's no way to scale the entire display output, between rendering the desktop and outputting it to the display. (Unless I'm mistaken and this is already implemented.)

EXPECTED RESULT
There's some way of doing scaling, whether that be a setting or a terminal command (even just a terminal command would give us parity with X11).

SOFTWARE/OS VERSIONS
Operating System: Debian GNU/Linux 13 (actually forky/testing, not trixie)
KDE Plasma Version: 6.5.3
KDE Frameworks Version: 6.20.0
Qt Version: 6.9.2
Kernel Version: 6.17.8+deb14-amd64 (64-bit)
Graphics Platform: X11
Processors: 12 × AMD Ryzen 5 3600 6-Core Processor
Memory: 16 GiB of RAM (15.5 GiB usable)
Graphics Processor: AMD Radeon RX 6600

ADDITIONAL INFORMATION
On X11, I think this is actually a subset of a general display transform mechanic. That's a pretty cool feature to have, and it would be cool if KWin implemented it, but it also might be overkill!

-- Frost

Comment 1 David Redondo 2025-12-02 10:36:17 UTC

On wayland you can select a scale for each output, it can be greater or lower (or equal) to one.

Comment 2 forestbeasts 2025-12-02 18:56:39 UTC

Uh, that looks like it's the widget toolkit scaling. That's not what I'm talking about, I'm talking about actual _output_ scaling.

(That does look like it handles the "taking huge screenshots" case, but nothing else.)

Comment 3 forestbeasts 2025-12-02 19:04:38 UTC

Okay, it also works for "desktop on a low resolution screen" case, and I tried a game and it seems to have picked up the scaling and allowed 4K on a 1080p screen! Though I have no idea what native Wayland games would do.

So this is much less pressing. Still would be nice, though. Especially to get nearest-neighbor upscaling on a 4K screen.

Comment 4 John 2025-12-03 22:04:45 UTC

I would like something like this also for the case when no screen (monitor or TV) is on or is not connected at all to the computer so I can use it with Sunshine server to give me 2K or 4K resolution or whatever is closest to what I have on the computer where I'm running the Moonlight client.
Since the source doesn't have any screen turned on or connected at all, it shouldn't matter the size of the resolution I'm requesting.
But I guess something like this need be fixed first:
https://bugs.kde.org/show_bug.cgi?id=511130

And with WINE-Wayland getting more and more fixes and probably being pretty in a pretty good shape when WINE 11 is released next year, it might be good for that too.