Re: [Gimp-developer] Gegl gaussian blur gamma error

[Øyvind Kolås <pippin gimp org>]

On Mon, Aug 6, 2012 at 7:35 PM, Elle Stone <l elle stone gmail com> wrote:
> On 8/5/12, Øyvind Kolås <pippin gimp org> wrote:
> I don't think I understand what the preceeding sentence says. I think
> it says that ultimately, when all changeover to gegl/babl is complete,
> Gimp should *not* allow the user the option of assigning one or
> another ICC color space profile to an image, and *not* allow the user
> to convert an image from one ICC profile to another. But that can't be
> right, can it?

I'll try to explain the desired situation in the end differently:

Files coming into GIMP and going out of GIMP might have assigned ICC
profiles, this is for import and export. There is no such things as a
working space in GEGL buffers flowing between operations in the graph
have defined color spaces and each node/operation have their own logic
for preferred working space and the raster data is converted before
processing. ICC conversion should only happen on import, to a well
defined babl supported color space, and on export to whatever
preferred color space the user has. The babl color spaces used by GEGL
have unbounded gamuts, and the conversions in use are precise
conversions rather than conversions implemented using interpolated 3d
lookup tables. The consequence of this is that all blending,
resampling (scale/rotate), blurring etc. should happen with linear
gamma.

There should be ways to change the colors in a buffer to correct for a
wrong profile. As well as deciding that you want to export images from
the composition with a different profile from the input.

/Øyvind K.
-- 
«The future is already here. It's just not very evenly distributed»
                                                 -- William Gibson