Let's make this bug report more general: The keyboard icons, the battery icon and the switch user icon look all blurry right now.

Cannot reproduce with git master. Can you post a screenshot of how it looks for you?

Created attachment 126633 [details]
Screenshot.

(In reply to Nate Graham from comment #2)
> Cannot reproduce with git master. Can you post a screenshot of how it looks
> for you?

Sure. At best look at a 100% crop.

Created attachment 126636 [details]
Looks fine for me

Thanks. I'm attaching how it looks for me. Can you try again with Plasma 5.18?

(In reply to Nate Graham from comment #4)
> Created attachment 126636 [details]
> Looks fine for me

Indeed. Mmm, let me report back when I receive the 5.18.X update. :)

(In reply to Nate Graham from comment #5)
> Thanks. I'm attaching how it looks for me. Can you try again with Plasma
> 5.18?

Still the case on :-( 

Operating System: Manjaro Linux 
KDE Plasma Version: 5.18.3
KDE Frameworks Version: 5.69.0
Qt Version: 5.14.1

SDDM's icons look fine by the way.

Strange.

I have the same result as Postix. (How could I screenshot the lock screen?) I have 1080p display with x1.5 scale (X11). I remember I reported it years ago but cannot find the old ticket.

And not only icons, but also avatars and cover arts of media player.

I saw Nate's screenshot has bigger fonts than Postix's. Maybe that is the reason that you got different results.

Operating System: openSUSE Tumbleweed 20200501
KDE Plasma Version: 5.18.4
KDE Frameworks Version: 5.69.0
Qt Version: 5.14.1
Kernel Version: 5.6.6-1-default
OS Type: 64-bit
Processors: 8 × Intel® Core™ i7-8550U CPU @ 1.80GHz
Memory: 31.1 GiB

I don't reproduce either with Plasma master SDDM from Kubuntu 20.04.

My hypothese is a missing environment variable not passed to sddm about HDIPI on arch/Marjaro, but ok on kubuntu/kde-neon.

(In reply to Méven Car from comment #11)
> I don't reproduce either with Plasma master SDDM from Kubuntu 20.04.
> 
> My hypothese is a missing environment variable not passed to sddm about
> HDIPI on arch/Marjaro, but ok on kubuntu/kde-neon.

The issue is about lock screen, not SDDM.

(In reply to Guo Yunhe from comment #12)
> (In reply to Méven Car from comment #11)
> > I don't reproduce either with Plasma master SDDM from Kubuntu 20.04.
> > 
> > My hypothese is a missing environment variable not passed to sddm about
> > HDIPI on arch/Marjaro, but ok on kubuntu/kde-neon.

Sorry I meant the lockscreen rather than SDDM.

> 
> The issue is about lock screen, not SDDM.
I checked again, and I do reproduce in the end with 1.5 scaling on a 1920*1080 screen on plasma near-master.

This is X only.

Is this one of the things that's fixed when setting PLASMA_USE_QT_SCALING=1? Can anyone who's affected check?

How to set PLASMA_USE_QT_SCALING=1? Do I need to compile plasma workspace/desktop with this parameter or is it a runtime environment variable?

(In reply to Nate Graham from comment #14)
> Is this one of the things that's fixed when setting PLASMA_USE_QT_SCALING=1?
> Can anyone who's affected check?

Can still reproduce it.

Runtime is fine. Run these commands in a terminal window:

```
export PLASMA_USE_QT_SCALING=1
rm ~/.cache/plasma*
plasmashell --replace
kwin_x11 --replace
```

...Then lock the screen and let me know if the problem is fixed.

@postix
Your original screenshot clearly shows the lock screen being rendered at 100% scale rather than 150% scale which would point to it being a lack-of-Qt-scaling issue. Does it look the same as it did before, or any different? If so can you attach a screenshot?

Created attachment 130374 [details]
Screenshot: PLASMA_USE_QT_SCALING=1, scaling 1.5

(In reply to Nate Graham from comment #18)
> @postix
> Your original screenshot clearly shows the lock screen being rendered at
> 100% scale rather than 150% scale which would point to it being a
> lack-of-Qt-scaling issue. Does it look the same as it did before, or any
> different? If so can you attach a screenshot?

1) Scaling 1.5
2) PLASMA_USE_QT_SCALING=1 in /etc/environment and /etc/sddm.conf section [x11] (necessary?)
3) reboot
4) Ctrl+L 

Are the steps fine? This way it looks blurry.

You're still getting an unscaled lock screen somehow, hmm. It's being shown at 100%, not 150% scaling.

Can you try doing it like I suggested in comment 17?

> /etc/sddm.conf section [x11] (necessary?)
Not necessary. You can remove that and then instead go to System Settings > Startup and Shut Down > SDDM > Advanced > Click the "Sync" button.

In fact, after doing that, can you reboot again, and check to see if SDDM and the lock screen look okay?

(In reply to Nate Graham from comment #20)
> You're still getting an unscaled lock screen somehow, hmm. It's being shown
> at 100%, not 150% scaling.

Yes, it's really weird.

> Can you try doing it like I suggested in comment 17?


> You can remove that and then instead go to System Settings >
> Startup and Shut Down > SDDM > Advanced > Click the "Sync" button.
> 
> In fact, after doing that, can you reboot again, and check to see if SDDM
> and the lock screen look okay?

I tried both, unfortunately without success. :-(

Created attachment 130375 [details]
Screenshot: PLASMA_USE_QT_SCALING=1, scaling 2.0

With scaling 2.0 and syncing SDDM, it looks fine (after a reboot).

Excellent.

However the fact that you had to sync your settings to SDDM to make it work is very weird to me, but we've gotten another report of that too, so I'll dupe it.

*** This bug has been marked as a duplicate of bug 423600 ***

(In reply to Nate Graham from comment #23)
> Excellent.
> 
> However the fact that you had to sync your settings to SDDM to make it work
> is very weird to me, but we've gotten another report of that too, so I'll
> dupe it.
> 
> *** This bug has been marked as a duplicate of bug 423600 ***

FWIW, it only works for scaling 2.0, for 1.5 the problem persists. 
Does syncing only update /etc/sddm.conf or does it also something else?

(In reply to Postix from comment #22)
> Created attachment 130375 [details]
> Screenshot: PLASMA_USE_QT_SCALING=1, scaling 2.0
> 
> With scaling 2.0 and syncing SDDM, it looks fine (after a reboot).

(In reply to Nate Graham from comment #23)
> Excellent.
> 
> However the fact that you had to sync your settings to SDDM to make it work
> is very weird to me, but we've gotten another report of that too, so I'll
> dupe it.

I'm happily testing.. ;) It's not a dupe. I went back to scaling 1.5, rebooted, then changed to scaling 2.0 (without syncing or rebooting) and locked the screen: Scales and looks like the 3rd attachment [1].


[1] https://bugs.kde.org/attachment.cgi?id=130375

Created attachment 130380 [details]
Screenshot: Screenshot: PLASMA_USE_QT_SCALING=1, scaling 1.5 (from scaling 2.0, no reboot)

Now I can do the same coming from scaling 2.0 and scale to 1.5 without syncing and rebooting and voilá, the locked screen displayes sharp crisp icons. However, once I reboot, they are blurry again!

Created attachment 130381 [details]
Animation: Scaling 1.5 (rebooted) vs 1.0 (no reboot, coming from 1.5)

I went back to scaling 1.5 (reboot) and scaled to 1.0 (no reboot, no syncing) and locked the screen: 

The icons become bigger and sharper for 1.0, besides the battery icon, which becomes smaller in fact. I made an animation for you to better see the difference ...

Summing up:

Integer scaling like 1.0 and 2.0 look as expected w/ or w/o a reboot/syncing.
Fractional scaling like 1.5 never looks fine on my side for the lock screen*.


*The login-in screen, despite beeing SDDM as well(?!) looks always fine.

Is this X or wayland?

Could you see if deleting the plasma cache makes a difference?

Relevant: https://invent.kde.org/frameworks/plasma-framework/-/merge_requests/50

Created attachment 130382 [details]
Animation: Scaling 1.0, 1.5 (always rebooted)

(In reply to David Edmundson from comment #29)
> Is this X or wayland?
> 
> Could you see if deleting the plasma cache makes a difference?

That's X11. rm -rf ~/.cache/plasma* before invoking Ctrl+L did not make any difference.

Created attachment 130383 [details]
Photograph: Wayland Lockscreen with Scaling 1.5

As I don't know how to take a screenshot of the lock screen at Wayland -- I used the delay function of spectacle at X -- I took a bad photograph.

Scaling 1.5 looks sharp here. Not sure if everything is as big as it should be though?

(In reply to Nate Graham from comment #17)
> Runtime is fine. Run these commands in a terminal window:
> 
> ```
> export PLASMA_USE_QT_SCALING=1
> rm ~/.cache/plasma*
> plasmashell --replace
> kwin_x11 --replace
> ```
> 
> ...Then lock the screen and let me know if the problem is fixed.


For me it is still blur. (But it fixed the size of context menu on panel and desktop).

Created attachment 130386 [details]
Even panel/launcher icons becomes blur after setting PLASMA_USE_QT_SCALING=1

(In reply to Guo Yunhe from comment #34)
> Created attachment 130386 [details]
> Even panel/launcher icons becomes blur after setting PLASMA_USE_QT_SCALING=1

Can you delete the plasma SVG cache and restart plasmashell? I have a sneaking suspicion that this is caused by Bug 424615.

(In reply to Nate Graham from comment #35)
> Can you delete the plasma SVG cache and restart plasmashell? I have a
> sneaking suspicion that this is caused by Bug 424615.

I did remove ~/.cache/* before running the commands but the lockscreen and panel are still blur.

Darn. Thanks for checking.

I have the same problem with 125% scaling. I thought only the avatar was blurry compared to SDDM. After seeing this bug I looked at the rest and all were blurry as mentioned.

Changing
/usr/share/plasma/look-and-feel/org.kde.breeze.desktop/contents/components/UserDelegate.qml
line 85
-sourceSize: Qt.size(faceSize, faceSize)
+sourceSize: Qt.size(faceSize * 1.25, faceSize * 1.25)
+width: faceSize

made the avatar as good as SDDM.

(In reply to Chandradeep Dey from comment #38)
> I have the same problem with 125% scaling. I thought only the avatar was
> blurry compared to SDDM. After seeing this bug I looked at the rest and all
> were blurry as mentioned.
> 
> Changing
> /usr/share/plasma/look-and-feel/org.kde.breeze.desktop/contents/components/
> UserDelegate.qml
> line 85
> -sourceSize: Qt.size(faceSize, faceSize)
> +sourceSize: Qt.size(faceSize * 1.25, faceSize * 1.25)
> +width: faceSize
> 
> made the avatar as good as SDDM.

Does :

 line 85
 -sourceSize: Qt.size(faceSize, faceSize)
 +sourceSize: Qt.size(faceSize * Screen.devicePixelRatio, faceSize * Screen.devicePixelRatio)

Work as well ?

This then could easily be adapted to a patch.

Yep.

Also, some observations:
1) SDDM's user account picture remains the same size even when the dpi changes. So it remains sharp.
2) The user manager KCM probably needs the same treatment.
3) The user picture is blurry on Wayland and adding the multiplication factor fixes it. But the switch user icon and battery icon are sharp by default on Wayland.

(In reply to Méven Car from comment #39)
> Does :
> 
>  line 85
>  -sourceSize: Qt.size(faceSize, faceSize)
>  +sourceSize: Qt.size(faceSize * Screen.devicePixelRatio, faceSize *
> Screen.devicePixelRatio)
> 
> Work as well ?
> 
> This then could easily be adapted to a patch.

Cool. Wanna send a merge request to https://invent.kde.org/plasma/plasma-workspace/-/merge_requests/?

A possibly relevant merge request was started @ https://invent.kde.org/plasma/plasma-workspace/-/merge_requests/686

Git commit 1c0c824cc51caf913faf0f6885a8cf6c2c9cc3b4 by Méven Car, on behalf of Chandradeep Dey.
Committed on 08/03/2021 at 06:42.
Pushed by meven into branch 'master'.

Use a bigger image for lock screen avatar

Lock screen avatar is blurry when using HiDPI scaling. This fixes that
by adding a multiplication factor to the size of the retrieved image.

M  +1    -1    lookandfeel/contents/components/UserDelegate.qml

https://invent.kde.org/plasma/plasma-workspace/commit/1c0c824cc51caf913faf0f6885a8cf6c2c9cc3b4

(In reply to Bug Janitor Service from comment #42)
> A possibly relevant merge request was started @
> https://invent.kde.org/plasma/plasma-workspace/-/merge_requests/686

This change introduced a regression, the fallback avatar in sddm is now a pixelated blur: https://openqa.opensuse.org/tests/1706054#step/start_wayland_plasma5/16

A possibly relevant merge request was started @ https://invent.kde.org/plasma/plasma-workspace/-/merge_requests/803

Git commit 2310fcb11173a166b357a453f3c727fe110f68f6 by David Redondo.
Committed on 20/04/2021 at 09:01.
Pushed by davidre into branch 'master'.

Import QtQuick.Window in UserDelegate

1c0c824cc51caf913faf0f6885a8cf6c2c9cc3b4 uses Screen but that is inside
in QtQuick.Window. This happens to work in the lockscreen (something else
importing it above it?) but breaks in the sddm theme, with the default image
being super pixelated because sourceSize defaults back to 22x22.

M  +1    -0    lookandfeel/contents/components/UserDelegate.qml

https://invent.kde.org/plasma/plasma-workspace/commit/2310fcb11173a166b357a453f3c727fe110f68f6

Reopening as the patches only fixed the user avatar. Battery and other icons remain blurry on X11.

There is no way to avoid blurriness when using HiDPI fractional Qt scaling with monochrome line-art icons. The icons are designed to be pixel- aligned at 100% scale, with the lines the thickness of one pixel exactly. But when you scale them by 150%, the lines get 150% thicker yet the pixels on your screen don't become 150% bigger. So the lines are no longer match the thickness of an individual pixel anymore, and hence, they become blurry. There is no way to fix this, sorry. It is simply something you need to live with when you use fractional scaling.

As a last remark, maybe you can explain to me why I still (Ferdora 34) don't see this issue on the login screen of SDDM with the Breeze theme, whose settings I have synchronized (in Systemsettings). 

All, really all icons are pretty much about the same size (measured by eye sight), but all are crisp.

What's the difference? Does SDDM use different kind if icons? :-)

And honestly, when I look sharply, the virtual keyboard icon now looks fine to me on the lockscreen(!), the only icons, which still do not look fine, are the battery status and visual hint icon in the password field.

So there has been some improvements and I wonder if those two icons left, couldn't be fixed as well?

SDDM doesn't use Qt scaling.

(In reply to Nate Graham from comment #51)
> SDDM doesn't use Qt scaling.

It's a Qt app, why doesn't use it Qt scaling? How does it scale then?

Why is the virtual keyboard icon now fine but the other not?

I am still very confused.

I also wonder, why the battery icon in the taskbar / systemtray, which is also about the same size, looks totally fine as well. Is it a different kind of icon? Different way of scaling?