Re: [Gimp-developer] Why the endless background conversions between linear and regular sRGB TRC?

["Guillermo Espertino (Gez)" <gespertino gmail com>]

El 31/08/12 14:05, Simon Budig escribió:
> With your "elimination" of the conversion in util.h you probably have 
> introduced visually different results for these kind of operations 
> (because e.g. the "addition" mode now adds up in a linear fashion, 
> while it earlier worked in Gamma mode). Of course it is debatable how 
> certain layer modes are supposed to work, but we also need to maintain 
> some backwards compatibility, so that old XCF files in a new Gimp look 
> the same as always.

I can only speak as a user, and I'm not sure about how other users feel 
about this, but even after 6 years of GIMP as my main and only bitmap 
manipulation software, I wonder how much of a big deal would be to ditch 
legacy appearance.
Of course several of my old files will look different, but if I think of 
it as a compromise to get a better GIMP, I'm all for it.
If I had to modify old files to make them look right in linear blending, 
it wouldn't be very difficult, and for those cases when getting the same 
results is critical, I still could use GIMP 2.8
Keeping legacy seems like an anchor for any program, and I wonder if 
keeping a legacy version as a separate product wouldn't make more sense 
than leashing the power of GIMP could have and squeezing dev's brains 
and time to get legacy co-existing with the new core.
I also wonder how much of GIMP's userbase uses it for complex composites 
with lots of layers and blending modes. Judging by the forums and 
tutorials out there, probably most of the users wouldn't notice if sRGB 
blending is replaced by linear.

There is a special case, though, that I wanted to leave for the end: 
Using GIMP for web mockups. Web browsers still use gamma blending for 
compositing RGBA images (a png with transparent background, for instance).
It's true that creating mockups in linear space would give different 
results, but that could be solved by adding a special variant of the 
"normal" blending (simple porter-duff alpha-over op) that gamma-corrects 
both inputs, composites them and then linearizes the result.
And maybe it doesn't have to be a special blending mode but a preview 
mode ("web preview" or something like that") that creates a projection 
with every alpha-over done in gamma-corrected space.

Anyway, that seems to be something that can be addressed later.

I'm curious to know how other users feel about this. I'd even suggest to 
comment everything legacy out in 2.10 and see how user community reacts.
If it's too bad for the majority of the users out there, GIMP 2.8 would 
be still an option (I mean, if there are users who chose to stick with 
2.6 because of the save/export thing, they can stick with 2.8 because of 
legacy looks). If nobody cares, happy-happy, joy-joy. :-)

Gez.