Bug 423553 - No smooth scrolling in small scales after Windows 10 2004 update
Summary: No smooth scrolling in small scales after Windows 10 2004 update
Status: RESOLVED NOT A BUG
Alias: None
Product: okular
Classification: Applications
Component: PDF backend (show other bugs)
Version: 1.10.1
Platform: Windows CE Microsoft Windows
: NOR minor
Target Milestone: ---
Assignee: Okular developers
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2020-06-26 16:32 UTC by savilov.tm
Modified: 2020-11-24 18:26 UTC (History)
0 users

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


Attachments

Note You need to log in before you can comment on or make changes to this bug.
Description savilov.tm 2020-06-26 16:32:11 UTC
SUMMARY

Scrolling after zoom is not smooth after Windows 10 2004 update.

STEPS TO REPRODUCE
1. Set up Windows 10 2004 update
2. Open PDF file
3. Zoom in text
4. Try to scroll

OBSERVED RESULT

Scrolling is smooth before zoom, but after zoom, it isn't.

EXPECTED RESULT

Always smooth scrolling.

SOFTWARE/OS VERSIONS

Windows 10 ver. 2004
Comment 1 Laura David Hurka 2020-11-06 17:40:36 UTC
I don’t understand how to reproduce this. (Possible that this has been fixed already.)

If this is still reproducible, can you try to explain it more precisely? E. g.: Which exact zoom scales did you use? Which kind of input did you use to scroll?
Comment 2 savilov.tm 2020-11-09 21:06:07 UTC
Unfortunately, this bug still exists. I use my laptop Lenovo Ideapad 720s-15. Therefore, the input device is the touchpad. I don't see this effect with a zoom scale of 150% and less. But at zoom scale 200% and higher scrolling became uneven. Sorry for a hazy explanation in June, I was preparing for my exam and didn't have a lot of time.
Comment 3 Bug Janitor Service 2020-11-24 04:33:58 UTC
Dear Bug Submitter,

This bug has been in NEEDSINFO status with no change for at least
15 days. Please provide the requested information as soon as
possible and set the bug status as REPORTED. Due to regular bug
tracker maintenance, if the bug is still in NEEDSINFO status with
no change in 30 days the bug will be closed as RESOLVED > WORKSFORME
due to lack of needed information.

For more information about our bug triaging procedures please read the
wiki located here:
https://community.kde.org/Guidelines_and_HOWTOs/Bug_triaging

If you have already provided the requested information, please
mark the bug as REPORTED so that the KDE team knows that the bug is
ready to be confirmed.

Thank you for helping us make KDE software even better for everyone!
Comment 4 savilov.tm 2020-11-24 11:10:31 UTC
I forgot to change the status.  See my previous comment.
Comment 5 Laura David Hurka 2020-11-24 12:34:59 UTC
Sorry, it is still unclear to me.

I understand that you use your touchpad for scrolling. Therefore, you should have pixel-wise scrolling. What we call “smooth scrolling” in Okular (since release 1.10 / 20.04), is not applied to pixel-wise scrolling with a touchpad. Smooth scrolling means to us that the content moves stepwise (like when you press the arrow keys), but with an animated transition.

(Apparently you have a 141dpi screen, so I estimate between 150% and 200% your Okular turns on tiled rendering.) Is the problem that the content briefly disappears when you scroll at high zoom scales?

(Another theory is that your Okular does not turn on tiled rendering for some reason, and so operates with too big pixmaps.) Is the problem that the performance is bad when you scroll at high zoom scales, so the content moves at irregular large steps instead of pixel-wise?
Comment 6 savilov.tm 2020-11-24 18:26:08 UTC
OK, I think this bug or not a bug is insignificant and both of us shouldn't spend time on it. Thank you!