KDE Plasma 5.16 Will Stop Resetting Your HiDPI Scaling When Changing Displays

[R41N3R]

Wayland? That's probably broken subsurfaces support - at this point probably the biggest KWin/Wayland issue left.

Yes, that is the most annoying bug on Wayland and I really hope that it will be addressed with Plasma 5.16, but so far there seems to be no really activity.

[dos1]

Yes, that is the most annoying bug on Wayland and I really hope that it will be addressed with Plasma 5.16, but so far there seems to be no really activity.

I wouldn't count on 5.16 as it seems fixing it will require quite an architectural overhaul, but hopefully it gets tackled before 5.17.

[RussianNeuroMancer]

Wayland? That's probably broken subsurfaces support - at this point probably the biggest KWin/Wayland issue left.

Even after fixing this, Wayland session will remain unusable for most of users anyway due to this postoponed issue: https://phabricator.kde.org/T5196

By the way, is anyone working on KWin software rendering optimizations? Last time I checked KDE and Gnome Xorg-session perform much faster in virtual machines, so VDI deployments is also Xorg-only thing, at least for now.

[R41N3R]

I wouldn't count on 5.16 as it seems fixing it will require quite an architectural overhaul, but hopefully it gets tackled before 5.17.

Well, at least we have some nicer looking icons ;-)

Rendering issues are probably not worth to be addressed :-(

[Damnshock]

KDE does have working fractal scaling support. I used it for a couple of months before switching back to Gnome.

Not in Wayland AFAIK

[linuxgeex]

The Xfce desktop has a global DPI setting in Appearance/Fonts. You have resolution, refresh rate, rotation and reflection settings per display.

It basically follows gnome/GTK3 HiDPI behaviour, which is buggy but usable.

I was talking about display hotplug maintaining xrandr preferences though. AFAIK no DE does this if you have one of the following setups:

laptop hotplugging a dock with one display:
1) on attach, dock's display become primary and laptop display turn off
2) on attach, dock's display maps above the laptop's
3) on attach, dock's display maps left of the laptop's
4) on attach, dock's display maps right of the laptop's rotated 90 degrees counter-clockwise.
5) keeping the desktop layout when the dock's display is powered off.

laptop hotplugging a dock with two displays:
1) basically any combination other than mirroring the lowest common display resolution, ugh
2) keeping the desktop layout when the dock's displays are powered off.

ie when docked, my laptop sits behind my TV with its display powered off. 50"TV becomes primary with a 23" portrait display to its right (used mostly for shells and media controls.) Each has their their own panels. Xfce manages the panels brilliantly, adding the portrait panel on hotplug, but sadly not managing the resolution, scaling, and rotation, so I have to run a script to fix it.

GTK manages HiDPI by making a brain-dead assumption that a 4K display user always intends to double the configured DPI. Xfce thankfully overrides this insane behaviour by default, so my 50" 4k display doesn't end up with fonts twice the size of my 1050p portrait monitor sitting beside beside it, and so long as there's 0px overlap of the 2 displays GTK doesn't have an aneurysm and start spazzing when I drag apps between the two displays, lol.

DPI is a fundamentally flawed concept that should be discarded sooner rather than later... but sadly it won't because it's too deeply ingrained. What should it be replaced by? 3 values:

1) absolute display size (most display provide this)
2) absolute distance at which the user intends to view the display, so that display arc-radians projected onto the viewer retina can be calculated.
3) the target viewer's comfortable lines per radian acuity at the intended distance (assume 3580 for a person with healthy vision.)

That would allow the system to generate UI and font scaling which is proportional to the capability of the user to see it, for the device in question, and in a way that works regardless of the manufacturer's assumptions about the distance at which a user might use the display. Ie. I'm far-sighted 50-year-old so I have to hold my iphone at a minimum of 31cm from my face before I can comfortably focus on the display. Therefore I need larger fonts than a near-sighted 6-year-old who can still focus on the end of their own nose, lol.

DPI doesn't solve that problem. "HiDPI" systems which are based on the broken DPI premise can't solve it because they're based on a system which forces users to outright lie to get what they need... <sigh />

[darkbasic]

Isn't Plasma supposed to use a different scaling factor for each display on Wayland? How does this cope with the environment variable required by QT/GTK (which is obviously not per-monitor)?

[Vistaus]

To some extent I can do these things with XFCE4, which is supposed to be much less advanced than KDE.

Have you learned nothing from debianxfce ??? lol

[skeevy420]

You realize that your monitor setup is very rare and even nuclear plants have simpler monitor setups, f.ex all monitors are the same.

That nuclear power plant is also running Windows 7. From that we can just deduct that neither Debian nor Xfce are good enough to run critical infrastructure.

That's how I used to have my setup when my craptop alternated as my truck's media player and as my home media center. Take the laptop, plug in the VGA and USB cables, and now it's a TV media PC. The only difficult part was dealing with the 1366x768 laptop output and the 1080p the TV liked, programs wanting to auto-open on the laptop and not the desktop...

Eventually made a TV user that disabled the laptop screen when that user logged in. There was probably a more elegant solution, but back in 2005 with Gnome, that worked good enough.

[tildearrow]

That nuclear power plant is also running Windows 7.

That's actually Windows XP.