On Fri, 31 Aug 2007 12:24:47 -0400, Robert L Krawitz <rlk@xxxxxxxxxxxx> wrote:> It sounds like what's happening is something like this:> > 1) Current JPEG quality setting is 85> 2) User selects "Use quality settings from original image if> original image is better"> 3) Original image has quality setting of 98> 4) User saves image> > 5) Now the current JPEG quality setting is changed to 98> > Is that correct? Almost. Step 2 currently happens automatically if the quality of theoriginal image is better than the defaults (because of the complaintsthat gimp was destroying the quality of some images without warning).But this may change, so step 2 could again require an explicit actionfrom the user. > If so, then (5) seems wrong to me. [...] Yes, this is exactly what I tried to explain in my previous messages.The problem is that the JPEG plug-in and most other file plug-ins willautomatically re-use all settings from the last file that was saved. > My own preference is to err on the side of caution; I'd rather make a> mistake of saving at too high of a quality (which loses less> information) than too low. If I accidentally save a thumbnail at> quality 98 or 100, all I've done is wasted a little disk space; if I> save a good image at 85, I've lost a lot of data. And this is what is currently implemented: if the quality level of theoriginal image is higher than the current default value, then thequality from the original image will be selected automatically. Butsince the JPEG plug-in shares the same behavior as the other fileplug-ins, this new value is automatically remembered for the next timeyou save an image. The combination of these two things (using the original quality if itis higher, and the automatic re-use of the last values instead ofusing the defaults) causes the problem reported by Jakub: if you loadand then re-save many images that were saved at different qualitylevels, you end up with the last image saved at the highest qualitylevel (maximum value from all images), which may be much higher thanthe default value or than the original quality of that image. This is a bug that should be fixed. But after discussing thisbriefly with Simon in #gimp, I think that it would be better topostpone the real fix to GIMP 2.6 because it would not be possible tofix all (or even most) file plug-ins for 2.4. And if only the JPEGplug-in (and maybe PNG) behaves differently than other plug-ins, thensome users will probably complain or at least be confused. It may bebetter to postpone the real fix until all plug-ins support a way toload and save defaults, and maybe support multiple presets. -Raphaël_______________________________________________Gimp-developer mailing listGimp-developer@xxxxxxxxxxxxxxxxxxxxxxxxxxx://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-developer
