Handling of 4K displays in Jammy?

Development Discussion
#1

I've been using "small"4K UHD TVs an computer displays since Ubuntu-Mate 16.04. To me proper scaling means an 18 "point" font should be 0.25" tall (18/72) on the screen. Basically this has meant just setting my dpi in the Appearance->Fonts to something like 3840/36" = ~106 dpi and then adding 3 or 4 points to all the default font sizes because I'm old, and like to sit a bit further from the screen than most folks seem to do, especially with smaller screens.

I've noticed in Jammy Desktop daily build from Mar 26 installed to a new build with i9-12900 and my old Nvidia GTX-970 that the default picked up the 4K screen but scaled everything so the large 4K screen was scaled so it looked like 1920x1080 laptop screen meaning a terminal window was ~4X larger than in pixel dimensions in 4K that it would be in 1080p. This is clearly not what I want, I want things scaled so I could effectively display four 1080p screens as a "quad", my UHD TV effectively is the same number of pixels and x-y dimensions as four 17" laptop displays would be as a 2x2 array.

To get the previous behavior I needed to change the scaling in Nvidia Settings from auto to 100%. Is this a bug or a feature?

#2

Hi,

Different people will have a different view on suitable scaling. By default most OS's will default to 150% or even 200% when presented with a 4k display.

So bring up the default Mate monitor preferences app and set scaling to 100%.

You can then play about with font sizes etc elsewhere in the system.

I do not believe it is a bug - just the way the Linux community has gone with scaling.

Hope this helped and I stand ready to be corrected by more experienced Mate users. Just returned here after a long time away.

Regards Zeb...

3 Likes
#3

Unfortunately scaling is still semi broken in Jamm Mate. I use straight forward 2x scaling and upon re-login the window buttons are rendered unscaled. Disable/enable HiDPI fixes it until the next login. Its hugely frustrating so I had to move to Cinnamon which handles 2x scaling perfectly.

#4

I want 100% scaling for my 4K display so I get the equivalent of four 17" laptop 1080p screens in a "quad".

Seems Linux is starting to emulate Windows behavior -- 200% scaling is what my wife's Win10 laptop did when hooked to her 4K display while she was working from home during Covid -- looked exactly like her laptop screen only bigger! I can't see how this is useful unless you are using the 4K screen for a presentation and everyone is 4-8' away from the screen. YMMV.

Edit: I'm beginning to think HiDPI has become a mostly meaningless term that only leads to confusion, My 4K screen is about 110 dpi, an old 17" CRT might have been 72 dpi, so I wouldn't call my 4K "HiDPI".

When I think of "HiDPI" I think of dinky Apple iPhone "retina" displays with 300 dpi in like a 4" screen. The pixels are largely wasted in invisibility unless you make everything 2-4X larger so you end up viewing effectively 150 or 75 dpi. Unless the screen is being "projected", I just don't see the practical benefits. Its not like with a laser printer where 300 or 600 dpi is the minimum to get a decent color gamut to print "Sunday Supplement", if you remember them! :slight_smile: image quality.

#5

Yeah that's a common discussion. But that doesn't mean that such obvious bugs shouldn't be fixed.

Simple integer scaling is a common use case whether people think it makes sense or not.

I read a lot of text on the screen and even an upscaled 4k screen resulting in a large 1080p panel gives a vastly superior result in terms of crispness and clarity. Why do I say so? Because I tried to downgrade back to 1080p screens several times due to the sad state of display scaling in Linux.