Screen jumps on touchpad scroll

[Alad Wenter]

Quoting from the original debian report:

https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=807115

   * What led up to the situation?
   When using vertical two finger scroll to scroll a PDF in qpdfview,
   the screen may jump half a page up. This happens randomly, but more
   often when the document area was not focused before.

   * What outcome did you expect instead?
   Scrolling via other means, such as the trackpoint, works as expected.
   The window manager in question is i3. Building 0.4.15 from source did
   not solve the problem.

I use XFCE4 and can reproduce it there, FWIW.

[Adam Reichold (adamreichold)]

Hello Alad,

I tried to reproduce this using a machine with a touch pad available to me running KDE 5 but with a Qt4-based qpdfview build but were unable to do so. As the Debian bug report indicates a Qt5-based build, could you check whether Qt4-based builds also show this? Could you also try to check if this is somehow related to the focus being on the page number or view mode combo boxes in the tool bars? The can trigger page navigation if they loose the focus.

Best regards, Adam.

[Alad Wenter (the-changing-side)]

Hi,

When moving the focus to the view mode, the page indeed moves up, but in this case I didn't have the focus there. I can reproduce it a bit easier when working in a different window for some time, then moving back to qpdfview.

I'll try with a Qt4 version as instructed.

Thanks for your interest,

Alad

[Alad Wenter (the-changing-side)]

As predicted, I haven't been able to reproduce this issue with a Qt4-based version of qpdfview 0.4.16. I've found a related Qt5 bug report:

https://bugreports.qt.io/browse/QTBUG-38274

And possibly:

https://bugreports.qt.io/browse/QTBUG-42415
https://bugreports.qt.io/browse/QTBUG-49294

Thanks,

Alad

[Adam Reichold (adamreichold)]

Hello again,

thank you for referencing the related Qt bug reports. As this seems to be based on the interaction of Qt5 and XInput2 and affect applications generally, I am closing this in qpdfview.

Best regards, Adam.