Sub-pixel positioning

Adrian Page adrian at
Wed Mar 17 00:17:20 CET 2004

On Tuesday 16 March 2004 8:02 pm, Roger Larsson wrote:
> > Using valgrind to profile KisToolBrush::mouseMove() with a pipe brush,
> > about 80-90% of the time is spent in computeDab(), and around 10% in
> > compositeCopy() and compositeOver(). The compositing code also has plenty
> > of room for improvement, part of which would be using premultiplied alpha
> > for the RGBA buffers. We can also replace division by shifts and optimise
> > for each channel depth we support.
> Yea but how much time is spent in X because of what Krita does?
> (I had 60%...)
> Please try with my patch (for brushes).

I tried your patch, but on my system the lag it introduces makes it feel 
worse. Perhaps that's why I don't get as much time spent in X when profiling, 
as for me, X is less of a bottleneck?


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