Bug 438912 - No output from KMagnifier on Wayland
Summary: No output from KMagnifier on Wayland
Status: REOPENED
Alias: None
Product: kmag
Classification: Applications
Component: general (other bugs)
Version First Reported In: 21.04.2
Platform: Manjaro Linux
: HI normal
Target Milestone: ---
Assignee: sarang
URL:
Keywords: wayland-only
: 468885 472320 472437 485291 492727 500706 504820 507039 (view as bug list)
Depends on:
Blocks:
 
Reported: 2021-06-19 13:36 UTC by Dominik Adrian Grzywak
Modified: 2025-11-20 14:41 UTC (History)
23 users (show)

See Also:
Latest Commit:
Version Fixed/Implemented In:
Sentry Crash Report:


Attachments
(Screenshot) KMag on Wayland has no output but a window frame (350.73 KB, image/png)
2021-06-19 13:36 UTC, Dominik Adrian Grzywak
Details

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Description Dominik Adrian Grzywak 2021-06-19 13:36:21 UTC
Created attachment 139515 [details]
(Screenshot) KMag on Wayland has no output but a window frame

SUMMARY
Since no one reported this long-standing bug here yet, i will.
KMag has no output while running on Wayland – in the place where the output should be, it just shows a window frame (see attachment).
I also tried another modes, but they also don't work.

STEPS TO REPRODUCE
1. Be running on KDE Wayland session (probably not just on KDE Plasma, but didn't test the others)
2. Run Kmag
3. Here's the bug, you can also test another modes, but they also don't work.

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: Manjaro Linux (Unstable branch)
(available in About System)
KDE Plasma Version: 5.22.1
KDE Frameworks Version: 5.83.0
Qt Version: 5.15.2
Comment 1 indecisiveautomator 2021-10-27 16:40:03 UTC
Still a bug, affecting me on Arch Linux with Plasma 5.23.2. It's not an application I use very often but it is annoying when I need to use it.

Possibly related to issues surrounding global cursor positioning being unavailable under Wayland (see #430781), which there is no real solution for it seems like.
Comment 2 skierpage 2022-03-09 21:38:45 UTC
At least someone should update the README, TODO (20 years old!), and https://apps.kde.org/kmag/ to say "kmag does not work on Wayland yet".

I couldn't find an alternative. The gnome-mag binary seems unavailable, I think it became a Gnome shell service. There's a System Settings > Desktop Effects > Magnifier effect, but I couldn't get it to work in Wayland.

One workaround is to take a screenshot with Spectacle. Maybe there's a way to use something like OBS to capture your screen and monitor a zoomed-in portion of it.
Comment 3 skierpage 2022-11-16 23:59:17 UTC
KMagnifier (I'm using full word here otherwise you can't find this bug) is still broken under Frameworks 5.99.0, Qt 5.15.6 on Wayland.
Comment 4 daf 2023-10-01 12:16:01 UTC
*** Bug 472320 has been marked as a duplicate of this bug. ***
Comment 5 daf 2023-10-01 12:16:18 UTC
*** Bug 472437 has been marked as a duplicate of this bug. ***
Comment 6 daf 2023-10-01 12:30:18 UTC
I'm still staying on X11 to use this accessibility tools, but it's not even listed on https://community.kde.org/Plasma/Wayland_Showstoppers .

Has this tool been replaced by something else already on Wayland? If not, is accessibility not being considered when migrating to Wayland by default?
Comment 7 Henning 2023-10-12 21:32:02 UTC
Just wanted to comment that for accessibility having this not work is a dealbreaker for many people. If KMag was ever a project people took seriously, than until it works on Wayland at least X11 has to be supported on all Distros etc...
Comment 8 Nicolas Fella 2023-10-12 21:50:34 UTC
What exactly do you use/need from KMag? There's a native Zoom functionality in KWin (Systems Settings > Desktop Effects > Accessibility > Zoom) that works on Wayland
Comment 9 Henning 2023-10-12 22:08:26 UTC
Thanks for the heads up, I forgot about this setting!

This is fixed for now then. KMag itself seems useless in this case, I will file a bug for Kinoite to remove it.

The two zoom options are perfect (If I imagine what I would want from such an app)
Comment 10 Nicolas Fella 2023-10-12 22:15:30 UTC
I'm still interested to know whether there are relevant use cases that KMag covers that the native KWin feature doesn't.

Making the existing KMag code work on Wayland would likely be difficult at best, so the better path forward would most likely be to amend the KWin functionality instead
Comment 11 Jaak Ristioja 2023-10-13 08:37:09 UTC
I have regularly used KWin to inspect individual pixels, e.g. for GUI and web design, when things need to be pixel-perfect. The KWin zoom functionality is insufficient for this because it blurs the pixels, making it difficult to inspect individual pixels and their boundaries. I think KMag also drew a hairline grid between the different pixels when zoomed in.
Comment 12 Rafael Linux User 2023-10-13 10:29:49 UTC
(In reply to Jaak Ristioja from comment #11)
> I have regularly used KWin to inspect individual pixels, e.g. for GUI and
> web design, when things need to be pixel-perfect. The KWin zoom
> functionality is insufficient for this because it blurs the pixels, making
> it difficult to inspect individual pixels and their boundaries. I think KMag
> also drew a hairline grid between the different pixels when zoomed in.

I agree. In fact, this feature of Plasma even zoom all other connected monitors. I use Kmag with applications (like Java based or Wine launched executables)  that shows all text 1/5 my desktop size, being impossible to read without magnifying locally.
Comment 13 Henning 2023-10-13 19:51:24 UTC
okay in this case i think it should be reopened.

missing features currently: pixel perfect zooming and a hairline
Comment 14 rosswzyang 2024-02-04 14:35:36 UTC
(In reply to Henning from comment #13)
> okay in this case i think it should be reopened.
> 
> missing features currently: pixel perfect zooming and a hairline

still exists on plasma 6 currently
Comment 15 bugsie 2024-04-10 17:55:06 UTC
*** Bug 468885 has been marked as a duplicate of this bug. ***
Comment 16 bugsie 2024-04-10 17:59:37 UTC
*** Bug 485291 has been marked as a duplicate of this bug. ***
Comment 17 Rafael Linux User 2024-04-10 19:38:05 UTC
> still exists on plasma 6 currently

Still doing nothing in Plasma 6
Comment 18 Ahmed Faisal 2024-05-02 19:47:01 UTC
Ignored, as always. All accessibility related bugs / feature requests in this decade!
"Importance normal". Ok, this maybe right for you. For us, visually impaired, it renders the whole system useless.
Microsoft Windows is still on my system, not for Adobe software, not for office, not for games. It's a simple feature that wasn't by the way supported on their system last year(!!): the zooming in their magnifier wasn't following typing in editors, but now it follows.
I reported that in Linux's best magnifying tool: the gnome zoom. The output? They just kept asking me for proofs and steps to reproduce (I've even been asked for a video screencast for a problem that exists in every gnome installation!!!).
This is terribly off-topic. I know.
But here in Kmagnifier I confirm this bug. It's in every kmag that runs on any Wayland desktop (e.g. hyprland) on any distro.
Comment 19 Nicolas Fella 2024-05-02 20:09:32 UTC
It was not ignored. It was pointed out that we already have a fully functional screen magnification tool on Plasma Wayland, so accessibility use cases are already covered
Comment 20 Ahmed Faisal 2024-05-02 22:16:07 UTC
(In reply to Nicolas Fella from comment #19)
> It was not ignored. It was pointed out that we already have a fully
> functional screen magnification tool on Plasma Wayland, so accessibility use
> cases are already covered

No, it was not.
To elaborate my point, I would like to point to two famous applications for desktop magnification. the Gnome's and Cinnamon's. Those two examples by name has two types of zooming:
1- Full screen zooming: the same one applied in KDE Plasma -that you mean by "got covered", and xFce, and Compiz and probably others that I forget about or did not know of.
2- Projected zooming: I don't know if that was the precise term for it, because I made that up. 
The projected zooming is found only in Gnome, Cinnamon, Kmag and Xmag. Where zoomed image is displayed on a side window (Kmag, Xmag and Windows Magnifier) or a part of screen, make that top half, bottom half, right half or left half. as seen in Gnome and Cinnamon. not counting W.Magnifier as this feature still very crappy after all those years.

Conclusion: KDE Plasma gives full screen zooming. KMagnifier gives projected zooming. Meaning that you are able to see zoomed image and zoomed object in real size, so you can easily find your location in full view beside your zoomed view.
you can try it yourself in Cinnamon by writing anything in full screen zooming (here you will realize the importance of zooming-follow-typing feature) than make that right half where you can see the whole page you write in left half and the exact line you edit in right half (if you have 2 monitors this can be your whole right monitor!).

I hope I did put the matter the right, sufficient way. Greetings
Comment 21 Henning 2024-05-09 20:05:27 UTC
no they are not talking about this. 


Search for "zoom" in the plasma search and it will redirect you to KWin effects. Here you can select many different variants of partial screen magnification.

KMag is an X11 application and fundamentally incompatible with Wayland. This is because it is a standalone app, that, like very other X11 app can capture any area of the screen. It scales this area itself, by just increasing its size.

The correct way to do this on wayland is through the compositor, and this is what KWin effects do. They allow all and more what KMag could do.

I think a blog post about this is really much needed. The KWin effects work well and I heard from a blind gamedev that they are the best on Linux.
Comment 22 Henning 2024-05-09 20:12:56 UTC
So I think there may be some functionalities missing, not sure how important they are

- it seems on Plasma6 there only is a single type of "loupe" kwin effect? Not 3 variants of moving the area anymore, which is not good. Especially the "push zoom area edges to move" is important as it doesnt cause nausea.
- there may be a feature missing to split the screen in half, and have the normal display on the left, and the zoomed on the right
Comment 23 Unknown 2024-06-28 09:53:18 UTC
I agree with the fact, this is not a priority. But it is still a usable feature though. 

Kwin's Magnifier is somewhat say functional. Most people, like using Magnifier on Separate window that doesn't affect their workflow. So, This should be worked out.
Comment 24 Antonio Rojas 2024-09-06 20:09:41 UTC
*** Bug 492727 has been marked as a duplicate of this bug. ***
Comment 25 Antonio Rojas 2025-02-25 07:40:14 UTC
*** Bug 500706 has been marked as a duplicate of this bug. ***
Comment 26 Antonio Rojas 2025-05-26 15:23:41 UTC
*** Bug 504820 has been marked as a duplicate of this bug. ***
Comment 27 Ahmed Faisal 2025-05-27 15:30:09 UTC
(In reply to Ikel Atomig from comment #23)
> I agree with the fact, this is not a priority. But it is still a usable
> feature though. 
> 
> Kwin's Magnifier is somewhat say functional. Most people, like using
> Magnifier on Separate window that doesn't affect their workflow. So, This
> should be worked out.

This is how I use it. I have two monitors, always using one as a workspace and the other to magnify it. I do that in Window$ (I hate to admit, the best version out there for projected/full screen zooming, as it the only one actively supporting zoom-follow-typing in both applications and browser text boxes, that's another story.) and Wayland versions of Gnome and Cinnamon (both supports projecting zoom to a half on the screen which translate in my dual monitor setup to one of my screens) and that's it. nothing else supports projected zoom but KMag that we in threat of losing it after Wayland dominates. all other applications of zooming are full screen that doesn't even support zooming-follows-typing which -if combined with me not able to view original viewport beside zoomed one- renders it almost useless.
To put all that in straight-forward language:
- Wayland doesn't -and doesn't want- to support KMag, the best stand-alone projected zoom out there.
- Wayland only supports full screem zooming which is not suitable for practical and professional use.
- the only two forms of projected zooming in Wayland are not stand-alone apps, but either features in Gnome and Cinnamon.
Conclusion: 
The only usable desktops within Wayland-sphere for my use case and many other disabled computer users like myself are only Gnome and Cinnamon. that's leaves out KWin/KDE Plasma and all other window managers that doesn't supports projected zooming. all that forces us to either stick to Gnome and Cinnamon in Wayland or to just stay in the sinking ship of XOrg/X11.
No other choices out there.
I'll leave the status as is as it not evem my decision to take.
Comment 28 Ken Mankoff 2025-06-21 14:58:33 UTC
(In reply to Nicolas Fella from comment #10)
> I'm still interested to know whether there are relevant use cases that KMag
> covers that the native KWin feature doesn't.

KMag has a View > Color > Sub-menu that lets you simulate color deficiencies. I don't see that feature on the normal KWin option. This is an important feature.
Comment 29 Antonio Rojas 2025-07-14 18:32:07 UTC
*** Bug 507039 has been marked as a duplicate of this bug. ***
Comment 30 Roger Júnio 2025-07-15 04:07:59 UTC
Well, KWin does offer alternatives to KMag for zooming; however, I believe that for KWin to be a complete alternative to KMag, it would need to add a zoom mode precisely in the style of KMag: zooming through a window. For screen recordings for content creation purposes, the KMag-style zooming seems to be particularly convenient in some cases.
Comment 31 Antonio Orefice 2025-11-20 14:41:42 UTC
It is clear that Kmag under X11 has functionalities that wayland cannot offer on Plasma.
Still, I can't understand why this cannot or won't be fixed.

My workflow under X11 is working on monitor 1 and have on monitor 1 kmag opened while it "zooms" a screen part of monitor 2 while my hands are just coding shaders shown on monitor 2. ctrl-s triggers a shader compilation and instant on screen update.

Under wayland I've to stop using keyboard and move the mouse in the interested area, then hit the shortcut to activate the kwin effect.

To summarize:

1: The worklflow is slower
2: I lost te ability to see how the zoomed image changes in realtime ('ve to stop the magnifier, code, and activate it again)
3: I lost the ability to see pixel perfect image (not linear filtered) without a grid.