Re: [Gimp-developer] [Gegl-developer] babl roadmap

[Jon Nordby <jononor gmail com>]

On Oct 15, 2014 4:19 PM, "Elle Stone" <ellestone ninedegreesbelow com>
wrote:
> On 10/15/2014 08:30 AM, Øyvind Kolås wrote:
>
> > On Wed, Oct 15, 2014 at 2:11 PM, Elle Stone  wrote:

Hi, I fear you two are talking past eachother.

> I will ask again:
>
> For which specific RGB editing operations do you plan to convert the
image from fooRGB to unbounded sRGB before performing the operation?
> Either the answer is "None. For color-managed fooRGB images, all RGB
operations will be done on data encoded using fooRGB primaries."

The answer is (to best of my understanding): Typically none. When chosing
to work in myfavoriteRGB for one "scene" (can be a GIMP document), all
operations which specify that they work in any RGB color space, using
babl_format("scene:RGBA float") will operate on myfavoriteRGB data. So if
there is myfavoriteRGB image as input, and that also is the desired output,
there will be zero data conversions.

Supporting any RGB spaces should be the case for the vast majority of
operations dealing with RGB data, including multiply/invert and similar.
With respect to the roadmap, these operations are *currently wrongly
tagged* to only work in unbounded sRGB. This is only because we don't have
the new architecture implemented yet!

I say 'typically' because if some operation *does* specify
babl_format("RGBA float") to indicate that it just works with unbounded
sRGB, a conversion will happen. This should of course *only be used in some
cases*, when it actually just works with the specific format. I can't
immediably think of any usecase for this, but there probably are some.

I hope this addresses some of your concerns,
Regards Jon