Re: [Lcms-user] Softproofing with parametric tonecurve

[Tobias E. <me...@ho...>]

On Monday 20 June 2016 23:55:24 Marti Maria wrote:
> Hi Tobias,

Hi, sorry for the late reply.

> could you explain a little bit more how you use this profile with
> softproofing?

I am creating a transform with

cmsCreateProofingTransform(Lab_profile, TYPE_LabA_FLT, output_profile, 
TYPE_RGBA_FLT, softproof_profile, out_intent, INTENT_RELATIVE_COLORIMETRIC, 
cmsFLAGS_SOFTPROOFING | cmsFLAGS_NOCACHE | cmsFLAGS_BLACKPOINTCOMPENSATION);

and use that later with cmsDoTransform()

> What result do you expect?

I expect that the image is shown as if it was exported to the softproofing 
intent first.

> What are you getting?

With the profile with a parametric tonecurve (sRGB in my example, but there are 
others, too) the use of softproofing doesn't affect the image at all. It still 
looks the same as when no softproofing is enabled. Other profiles used the same 
way work though.

> This would
> help to catch the bug if this is the case

It might very well a bug on my side.

> Thanks
> Marti

Tobias

> On Jun 20, 2016 12:19 PM, Tobias Ellinghaus <me...@ho...> wrote:
> > Hello,
> > 
> > I am currently struggling to use a profile with a parametric tone curve
> > for
> > softproofing. Is there a know limitation regarding that? When I use a
> > straight gamma it works. Alternatively I can dump the profile to disk or
> > memory and read it again to get something working.
> > 
> > The code to create the profile is here:
> > 
> > https://github.com/darktable-org/darktable/blob/master/src/common/colorspa
> > ces.c#L286-L297
> > 
> > and
> > 
> > https://github.com/darktable-org/darktable/blob/master/src/common/colorspa
> > ces.c#L238-L284
> > 
> > I would appreciate any hints about what is happening.
> > 
> > Thanks
> > Tobias
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