It’s astounding to me that in Linux, in 2025, I can’t just simply output a custom resolution. You are probably typing a response right now with some xrandr nonsense and I PROMISE you, it won’t do it. I can’t even scale my screen within a normal resolution to make it fit within a boundary. But I can do this in windows with an nvidis gpu. Crazy
> You are probably typing a response right now with some xrandr nonsense and I PROMISE you, it won’t do it.
Skill issue. You probably held your keyboard wrong or something. Simple xrandr commands work fine like they have for decades. (Of course if you've moved to Wayland then who knows).
You don't have to use xrandr to create a custom framebuffer with scaling and/or centering, although it is capable of doing so. You can also use Gamescope (https://wiki.archlinux.org/title/Gamescope), which works on both X11 and Wayland, and with any GPU.
Traditionally it's used to launch a full-screen application, usually a game, but you can launch your window manager through it, if you want your desktop session to use a custom resolution with custom scaling and/or letterboxing.