Bug 226765

Summary: Panning with arrow keys in preview mode is slow
Product: [Applications] digikam Reporter: Julien Narboux <Julien>
Component: Preview-ImageAssignee: Digikam Developers <digikam-bugs-null>
Status: RESOLVED FIXED    
Severity: normal CC: caulier.gilles
Priority: NOR    
Version: 1.2.0   
Target Milestone: ---   
Platform: unspecified   
OS: Linux   
Latest Commit: Version Fixed In: 2.0.0

Description Julien Narboux 2010-02-14 09:27:47 UTC 
Version:           1.2.0svn (using KDE 4.3.5)
OS:                Linux

When panning using arrow keys in preview mode in DigiKam the label "Reduced Size Preview" is flickering and the whole process is very slow compared to mouse wheel scrolling.

Julien
Comment 1 caulier.gilles 2010-02-14 11:47:22 UTC 
Yes, it's slow because of these line :

http://lxr.kde.org/source/extragear/graphics/digikam/libs/widgets/common/previewwidget.cpp#839

...which call repaint() on viewport. I don't have found a good solution.

In fact the problem is that Qt4 catch keyboard _release_ event in case of key are not yet released ! I think to use a timer here to prevent this call if  keyReleaseEvent is called too shortly. 

Do you understand the problem ?

Gilles
Comment 2 Marcel Wiesweg 2010-02-14 14:41:07 UTC 
So the problem is that many events are sent in a short time?
1) What's the indication to use repaint()? Is update() not possible?
2) Yes, use a timer.
Comment 3 Andi Clemens 2011-07-24 12:47:32 UTC 
Is this issue fixed? I can not see any slowdown or flickering...
Comment 4 Marcel Wiesweg 2011-07-24 13:23:10 UTC 
Code is completely rewritten since then, so I guess we can close.