Claus Berghammer wrote:
> Hello Gimp Users and Developers,
> This is a follow up of Bug 557950 (which in fact isn't a bug, according to
> Sven Neumann ;-)
> As described in the “Bug”, scaling in Gimp 2.6 series is far slower, than it
> was in 2.4. Sven Neumann commented:
> “We have completely changed the scaling implementation. The new algorithm is
> slower for some cases, but that is not a bug.”
> Since there is no explanation WHY the algorithm was rewritten, I guess 2
> possible reasons:
>       1.)The old code did something wrong in some cases
>       2.)The new code was necessary due to GEGL integration
> For the first point, I compared scaling results from 2.4 and 2.6, and they
> are (ignoring some harmless alignment issues) 100% identical (using
> difference blend mode). I also cannot remember, that in the past years, the
> scaling routine in Gimp produced noticeable wrong results. (Beside the
> lanczos interpolation, that didn't work right, when it was introduced)
> So my question is, isn't it possible, to have both algorithms in Gimp, and
> let the user decide which one he wants to use? (Option in Scale Dialog) 
> If it was due to point 2, the GEGL integration, than can we expect a faster
> version of the new scaling routine? Or will it be automatically faster, when
> GEGL is integrated more/better?
> The current situation draws some users (not myself) to not use Gimp 2.6, and
> stick with 2.4 instead, because the difference in speed is so dramatically.
> Sincerely, Claus Berghammer

I'd be curious to see some benchmarks comparing 2.4 and 2.6 in this regard so 
that we know just how dramatically
different the speed is.

Eric P.
Gimp-user mailing list

Reply via email to