[Okular-devel] [Bug 247797] New: Middle Mouse Button zoom has jumpy behavior on second screen

Stephan Burkhardt oceanofsolaris at gmx.net
Sat Aug 14 01:10:06 CEST 2010


           Summary: Middle Mouse Button zoom has jumpy behavior on second
           Product: okular
           Version: 0.11
          Platform: Ubuntu Packages
        OS/Version: Linux
            Status: UNCONFIRMED
          Severity: normal
          Priority: NOR
         Component: general
        AssignedTo: okular-devel at kde.org
        ReportedBy: oceanofsolaris at gmx.net

Version:           0.11 (using KDE 4.5.0) 
OS:                Linux

When using the middle mouse button to zoom, okular "wraps" the upper and lower
screen border so that you can zoom seamless without beeing bound by your
screen. THIS is great!

On my second monitor however something odd occurs when traversing the screen
border: There is a huge jump (e.g. zoom factor jumps from 200% to 10%) with
only a tiny mouse movement. This is does not happen everytime, but only about
60% of the time. It seems to happen less often when okular is not maximized.

I assume that traversing the screen border is somehow counted twice, meaning
that the zoom jumps by the amount it would change when moving the mouse by
~1050 pixel. I had filed a similar bug for scrolling with the first mouse
button about 18 month ago, but this seems to be fixed now (was bug 167438 ).

Further info: Using Ubuntu 10.04, "kubuntu-ppa backport" packages of KDE SC
4.5.0. Window manager is Compiz, Desktop is Gnome (I will try this later with

This is obviously not a show-stopper, so it should be low priority. Furthermore
the first bug 167438 similar bug seemed to be caused by a qt bug  (QMouseEvent
is called twice for the same event), so it might be quite hard to fix it.

Reproducible: Sometimes

Steps to Reproduce:
Open a document with okular on your second screen, maximize the window.
Now hold the middle mouse button pressed to zoom in and out.
While doing so, cross the screen border several times.
Instead of zooming in and out smoothly, there will by a huge jump in zoom

Actual Results:  
Zoom factor jumps.

Expected Results:  
Zooming should work smoothly.

OS: Linux (x86_64) release 2.6.32-24-generic
Compiler: cc

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