Re: [Gimp-user] Scaling in Gimp 2.6 is much slower than in Gimp 2.4
Hi, On Mon, 2008-10-27 at 04:01 -0700, Claus Berghammer wrote: 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) Your analysis is wrong. There's a discussion about the problems and the solution in bug #464466 (and several other bug reports linked from there). This has also been extensively discussed on the gimp-developer mailing-list. Fact is also that scaling is not much slower in general. There are some cases where it became faster. Other cases became slower, but the results are of much better quality. Sven ___ Gimp-user mailing list Gimp-user@lists.XCF.Berkeley.EDU https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-user
Re: [Gimp-user] Scaling in Gimp 2.6 is much slower than in Gimp 2.4
Hello... @Eric P: Upscaling image: 500px - 5000px (bicubic): Gimp 2.6.1: 35,21 sec Gimp 2.4.7: 6,9 sec Downscaling layer: Image is 5000x5000 px, 2 white layers Scaling top layer to 2500x2500px (bicubic): Gimp 2.6.1: 7,85 sec Gimp 2.4.7: 4,78 sec @Sven Neumann: Thanks for your hint on the related bugthread. I will read it carefully to better understand the whole thing. Claus Eric P wrote: 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 ;-) http://bugzilla.gnome.org/show_bug.cgi?id=557950 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 Gimp-user@lists.XCF.Berkeley.EDU https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-user -- View this message in context: http://www.nabble.com/Scaling-in-Gimp-2.6-is-much-slower-than-in-Gimp-2.4-tp20185528p20202924.html Sent from the Gimp User mailing list archive at Nabble.com. ___ Gimp-user mailing list Gimp-user@lists.XCF.Berkeley.EDU https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-user
Re: [Gimp-user] Scaling in Gimp 2.6 is much slower than in Gimp 2.4
Hi, On Mon, 2008-10-27 at 04:01 -0700, Claus Berghammer wrote: http://bugzilla.gnome.org/show_bug.cgi?id=557950 I have done some more tests and I tend to agree that the multi-pass scaling doesn't improve the quality when upscaling. It's a very simple change to get upscaling perform more similar to what GIMP 2.4 has done. Could we perhaps move this discussion to the gimp-developer list? There your mail would have a chance to reach the developer who wrote the new scaling code. Thanks. Sven ___ Gimp-user mailing list Gimp-user@lists.XCF.Berkeley.EDU https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-user
[Gimp-user] Scaling in Gimp 2.6 is much slower than in Gimp 2.4
Hello Gimp Users and Developers, This is a follow up of Bug 557950 (which in fact isn't a bug, according to Sven Neumann ;-) http://bugzilla.gnome.org/show_bug.cgi?id=557950 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 -- View this message in context: http://www.nabble.com/Scaling-in-Gimp-2.6-is-much-slower-than-in-Gimp-2.4-tp20185528p20185528.html Sent from the Gimp User mailing list archive at Nabble.com. ___ Gimp-user mailing list Gimp-user@lists.XCF.Berkeley.EDU https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-user
Re: [Gimp-user] Scaling in Gimp 2.6 is much slower than in Gimp 2.4
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 ;-) http://bugzilla.gnome.org/show_bug.cgi?id=557950 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 Gimp-user@lists.XCF.Berkeley.EDU https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-user
