Re: [Linuxwacom-discuss] Wacom pen lagging when editing images

[Alexia D. <ale...@gm...>]

On Wednesday, July 28, 2010 22:13:23 Favux ... wrote:
> Hi Alexia,
> 
> I've been meaning to ask you about this for a while.  Several of us
> are noticing pronounced lag in Gimp with the stylus.  So it's a known
> issue due to refresh and an underpowered CPU?  That makes sense, my
> desktop CPU is old.  I'll have to see if that's true of the others.

Yes, its a known issue. 2.6 series already contains some code that should 
mitigate the issue, but at high zoom outs its effect is canceled out. A filter 
was installed, so that events more than 2x below both image and screen 
resolution are dropped early. the 2.7 series contains an optimization the 
brush outline side of things that limits the outline draw rate and stops 
drawing it completely if resources are needed for painting. There is also a 
patch that is incomplete, that should address this on the projection refresh 
side. With both patches applied, I can use full 1000px vector brush on A3 
canvas with my tablet *near* realtime. With just the outline fix, the limit 
remains around 600px brush. And this is with the new interpolation code, so no 
more ugly polygons when moving fast.  In 2.6 series on my hardware the limit 
is around 250px.


> xsetwacom set "Wacom Cintiq 21UX2 stylus" RawSample "4"  # default is 4,
> 1-100
> 
> Anything else we can try Alexia?
Nope. This is exactly what characterizes the bug. The application is 
overwhelmed by the events. Raising sample rate cuts the flow of events.