Bug 435492

Summary:	comic: wayland: popout mode: touchpad scrolling almost doesn't
Product:	[Plasma] kwin	Reporter:	Duncan <1i5t5.duncan>
Component:	input	Assignee:	KWin default assignee <kwin-bugs-null>
Status:	RESOLVED UNMAINTAINED
Severity:	normal	CC:	nate, plasma-bugs-null
Priority:	NOR
Version First Reported In:	5.21.4
Target Milestone:	---
Platform:	Gentoo Packages
OS:	Linux
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:

Description Duncan 2021-04-08 04:55:07 UTC

In popout mode with an oversize comic, touchpad scrolling is glaaaccciaaall.

Today's xkcd comic is huuggee, in popout mode it scrolls both ways on my 4k TV-screen monitor (firefox says the image at the png URL below is 4332x4838)! It appears Randall Monroe (author) forgot his usual downscale or something as the content isn't really beyond normal -- some of his comics squeeze a lot more content into rather more normal sized images.

Assuming he hasn't fixed it by the time this bug is checked it's #2447:

https://xkcd.com/2447/
https://imgs.xkcd.com/comics/hammer_incident.png

Attempting to scroll the huge comic demonstrates a bug. With a touchpad and the comic in popout mode (on wayland if it matters), attempting to scroll... almost doesn't! Movement is glacial (during an ice-age, not global-warming!). This is with scrolling speed adjusted for normal usage in the rest of kde/plasma.

Since various bits of kde have historically had the opposite problem, touchpad scrolling way too fast until fixed (which they generally are by now), at a guess the problem /might/ be that a fix for /that/ problem is being applied twice, thereby making it way slow instead of way fast. Maybe plasmashell itself has a general fix that got applied after a comic-strip-specific fix was already in place, without the comic-strip-specific one being removed?

Version is live-git plasma/frameworks (using the gentoo/kde overlay live-git packages). There's no version for that in the dropdown so I left it as unspecified. qt 5.15.2+ of course. kdeplasma-addons @ 39047eddf, updated today, altho IIRC I noticed this some time ago as well (perhaps when I was switching to wayland and encountering too many bugs to bother with all but the show-stoppers) so it's likely been happening for awhile, possibly forever.

Comment 1 Duncan 2021-04-08 05:12:08 UTC

Restarted plasma in X mode (using the libinput driver for the touchpad) and the problem does not occur there.  So it's wayland-specific.

Back on wayland again, I noticed something else funny with the scrolling too.  If I scroll all the way to image-right, it pops back to image-left! =:^(  From memory of the previous time a comic was big enough to trigger scrolling (IIRC that one was on a questionable content comic), it does the same thing vertically, popping back to the top from the bottom, tho I didn't bother forever-scrolling to the bottom to find out on this one.  (If you'd like I can file that as a different bug.)

Comment 2 Marco Martin 2021-04-08 17:56:08 UTC

related to libInput then

Comment 3 Duncan 2021-04-09 05:01:12 UTC

(In reply to Duncan from comment #0)
> Assuming he hasn't fixed it by the time this bug is checked it's #2447:
> https://imgs.xkcd.com/comics/hammer_incident.png

Looks like he resized it.

Comment 4 Nate Graham 2021-04-09 21:05:17 UTC

What do you mean by popout mode exactly? I don't see any scroll behavior at all on the applet's view on Wayland. Maybe that's the bug. :)

Comment 5 Duncan 2021-04-10 02:09:26 UTC

(In reply to Nate Graham from comment #4)
> What do you mean by popout mode exactly? I don't see any scroll behavior at
> all on the applet's view on Wayland. Maybe that's the bug. :)

I was wondering what to call it and popout mode is the best I came up with, hoping the meaning would be self-evident given it was specified (as opposed to normal display mode which there'd be no need to specify), but "self-evident" it obviously wasn't.

What I mean is the center-click/center-button-click mode where it pops out the comic by itself (well, with a drop-shadow) into the center of the screen at original comic resolution (the config checkbox label says "Middle-click on comic to display at original size", but doesn't mention that it pops out into a separate window in the middle of the screen).  Fine when the comic resolution is below that of the screen.  When it's not, scrolling is supposed to be possible, and it works on X, but on wayland, at least with a touchpad, not so much.

(If it matters the touchpad is an original Logitech t650 (wireless rechargable, using the same USB unifying receiver as my Logitech wireless keyboard), which wikipedia says came out in 2012, matching my feeling that I'd been using it nearly a decade.  (I don't have a traditional desk so there's no place for a traditional mouse to roam.))

Comment 6 Nate Graham 2021-04-13 22:10:33 UTC

Okay, I got the pop-out, and touchpad scrolling works fine for me.

Comment 7 David Edmundson 2023-09-06 10:38:54 UTC

This bug was reported against an outdated version of KWin. We have made many changes since the. 
If the issue persists in newer versions can you reopen the bug report updating the version number.