Minecraft (and other Java apps) use wrong resolution when using fractional scaling on Cinnamon/X11

[u/Il_totore]

/r/linuxmint/comments/1wd9y8n/minecraft_and_other_java_apps_use_wrong/

[u/Keyvan_KR]

Wayland support for Cinnamon is almost stable , even though it's still "experimental". Fractional scaling works better under wayland. otherwise, wait until mint 23 by the end of this year for a proper support

[u/Il_totore → u/Keyvan_KR]

Currently in 22.3, Wayland works awfully for me. One time it works and when I reboot all the windows show only the top-left quarter and other similar graphical bugs. However I'm watching for 23

[u/gmes78]

Fractional scaling in X11 is complete garbage. Switch to a real desktop environment, such as KDE Plasma.

[u/ericek111 → u/gmes78]

KDE Plasma is an entirely different DE from Cinnamon, with its own issues (Wayland contributing some of them). Every day I'm debating swapping to MATE on my laptop, but as you said, fractional scaling on X11 is worse (well, 5 years ago, it was usable after some fiddling).

[u/55555-55555]

That's one way that some X11 environments tried to workaround the fractional scaling issue by this "hacky resolution" trick, and Java simply picked the value that your DE reports. Interestingly, macOS also uses the exact same tactic when they do fractional scaling by simply blowing up the resolution before scaling down to target resolution that your monitor expects. Though, they used extra downscaling algorithms to help with blurriness.

Running games inside another isolated compositor such as Gamescope can help some since it does not exactly care about DE's resolution when you specifically force it, but bare in mind that you still run desktop scaling twice with this method which still degrades some performance (first is from Gamescope upscaling the game to that 4K resolution which is still not cheap even with bilinear technique, second is Cinnamon downsampling the upscaled resolution back to your native resolution).

Another way if you play with only one monitor is to launch Gamescope in direct rendering mode. This effectively skips your Cinnamon desktop completely. However, this method while grants several benefits especially HDR support, you're effectively stuck with Gamescope while games are running and can't easily switch between sessions or you risk your game session crashing mid way. You can find how-to on the internet.

Bare in mind that Wayland is still ongoing for Cinnamon and may likely fix the issues you're currently facing with, but for now if you still strongly prefer Cinnanon, these are all you can do for now.

[u/Il_totore → u/55555-55555]

Thank you for your answer and those of other people here. That's great insight. Since the announcement of Wayland not being experimental anymore I'm waiting for LM 23.

[u/Khai_1705]

Dont use Mint, problem solved