Re: [Gimp-developer] Overlay Mode - fix.

[Michael Natterer <mitch gimp org>]

On Wed, 2012-11-14 at 11:57 +0400, Paul Geraskin wrote:
> Hi again.
> 
> I talked to Krita developer "Boud"  by IRC and he said many interesting 
> things about linear RGB.
> He said that there is no need to convert to Linear RGB. Krita does not 
> convert anything. It only mixes layers.

I suggest you trust what the gimp developers say about what needs
and needs not to be done in gimp code.

> So everything is simplier. You just need to implement my patch and make 
> "New Overlay"/"Legacy Overlay"
> for new/old XCF formats.

No, it is exactly as i said.

--mitch

> Entire talk:
> [11:36]<boud> mifth: yes
> [11:38]<mifth> i have a tlkt to gimp devs about Overlay mode. There is a 
> question: do you convert to Linear RGB layers before mixing and then to 
> sRGB/RGB16 after mixing?
> [11:38]<mifth> talk*
> [11:39]<boud> no -- krita users can create their images in linear rgb 
> and work in that mode if they want, but otherwise, everything is done in 
> the current colorspace
> [11:39]<mifth> i mean in Krita of course
> [11:40]<boud> this is different from gegl, which, afaik, always works 
> with 32 bit floating point linear rgb
> [11:41]==thorwil[~thorwil@79.251.116.204] has joined#krita
> [11:42]<mifth> For eaxmple i created an image RGB8 in Krita. Then i did 
> some layers with different modes. Does Krita convert RGB8 to Liner RGB 
> to mix layers?
> [11:43]<boud> no -- if you have layers in different color models, krita 
> will convert those layers to the image model before composition
> [11:45]<mifth> Gimp devs say that they should convert to liner RGB 
> before mixing layers? Are they right?
> [11:45]<mifth> i'll post some their posts now
> [11:45]<boud> I'm on the mailing list :-0)
> [11:45]==LukasT[~zil00064@213.95.68.61] has joined#krita
> [11:45]<mifth> aha cool
> [11:46]<mifth> what do you think about that talk?
> [11:46]<boud> it's something that one can debate... the thing is, that 
> yets, there are advantages. But artists often don't want the way linear 
> rgb works, it confuses them
> [11:46]<boud> it affects the way layers are blended together, and they 
> are used to the non-linear system
> [11:46]<boud> so krita gives people a choice: choose to work in linear 
> rgb, or not
> [11:48]==home[~home@unaffiliated/home] has joined#krita
> [11:48]<mifth> interesting..
> [11:48]<boud> it also means you can easily experiment with the 
> differences in krita :-)
> [11:49]<mifth> where can be switching to linear in Krita?
> [11:49]<Bugsbane> I've just updated Krita.org to the latest version of 
> Joomla and it's plugins. It should all work fine, but if anyone comes 
> across anything weird, I'd appreciate hearing about it!
> [11:49]==MrBeast[~foo pD9508D90 dip0 t-ipconnect de] has quit [Read 
> error: Connection reset by peer]
> [11:50]<boud> Bugsbane: ok!
> [11:50]<boud> mifth: image/convert image type, select an scRGB profile.
> [11:50]<mifth> boud: other question: Is it ok to mix layers with 
> different modes without convertion to linear RGB?
> [11:51]<boud> yes, in krita it is
> [11:51]<mifth> cool
> [11:51]<boud> but afaik, krita is the only application that allows you 
> to have layers of different color models
> [11:51]<mifth> thank you for talking
> [11:51]<mifth> i'll post it to Gimp mailing list
> [11:52]<boud> you're welcome
> [11:52]<boud> oyvind kolas (pippin) knows how krita works, btw, but he 
> thinks we're doing it wrong by allowing the user that flexibility
> 
> 
> 
> On 13.11.2012 21:37, Michael Natterer wrote:
> > The problem is much bigger. Almost *all* of our layer modes
> > will be "Legacy", and the new modes will operate in linear
> > light. Just adding a hack for overlay is not going to
> > fix the root problem.
> >
> > --mitch
> >
> 
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