[Qgis-developer] rendering current line in Grass digitizer is very slow

[Maciej Sieczka]

Radim Blazek wrote:
> GRASS edit in 0.8 is using QgsRubberBand (XOR rendering
> does not work anymore IIRC) and it is probably slow because
> it is not designed for complex graphics.
> I dont know if it can be improved.

Guys,

I don't know how actuall Radim's comment is currently, but I want to
let all QGISers know that the main (if not the only) reason for the
slowdown I suffered from were Ubuntu Dapper's *default* XORG settings
for ATI cards. You can find a solution to the problem in my last post
in the https://svn.qgis.org/trac/ticket/295.

In short, if using the Dapper's default settings for ATI graphics,
which are driver 'radeon' and XAA accel mode, and suffering from
slow-downs in 2D graphics, you should add:

Option "XaaNoOffscreenPixmaps"

to your xorg.conf.

Without this tweak the performance of my X700 (and X600 on another
machine) ATI board was sluggish in 2D, but somehow bearable until I
noticed it in QGIS. That's why I blamed it on QGIS at first. Sorry for
the fuss. It seems QGIS has nothing to do with it.

Cheers,
Maciek