[FreeNX-kNX] Performance with KDE 4.8 + Qt 4.8

Frédéric COIFFIER fcoiffie at gmail.com
Mon Jan 16 14:41:05 UTC 2012

Since first versions of Qt 4, the performance of this toolkit through 
NX/FreeNX has decreased (compared to Qt3) : it slows to refresh and there are 
many glitches.
Moreover, Qt 4 can supports different graphic backend :
 - native which uses X11
 - raster which makes many operations on an internal graphic buffer without 
using X11.

On a local machine, raster performs well but it is really slow with a remote 
X11 or NX/FreeNX.

It seems that the next version of KDE 4.8 (associated with Qt 4.8) will select 
raster by default.
I have found a workaround to keep raster on a local connection and to select 
native with FreeNX (ugly hack) :

/usr/bin/nxnode :
          [ "$EXPORT_SESSIONID" = "1" ] && export NXSESSIONID="$sess_id"
+         export QT_GRAPHICSSYSTEM=native


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