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

[Paul Geraskin <paul_geraskin mail ru>]

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


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