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List:       koffice-devel
Subject:    Re: inheritance in Pigment
From:       Cyrille Berger <cberger () cberger ! net>
Date:       2006-09-06 8:23:11
Message-ID: 200609061023.11581.cberger () cberger ! net
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> > Yes I know :) That's not a problem if KoColorSpace isn't pure virtual,
> > the more I think about it, the more I wonder if the fallback (to QColor
> > or lab) shouldn't be available in KoColorSpace.
>
> As long as it doesn't depend on lcms, that's possible.
hum, it would, why is it a problem ? Not directly, it would require to have 
access to KisRGBColorSpace (or the LAB one) and use it

> > if you can convert to rgb, you can convert to lab ;) if you can't convert
> > to RGB you can't display, so I assume that all colorspaces can convert to
> > LAB.
>
> That would be an extra step for no gain: if you go to 8 bit rgb, then to
> lab, then back to rgb then back to the original, you'll lose more than if
> you were to use just rgb.
On the other hand some colorspaces will loose more when fallingback to rgb 
than to lab, so I suggest to let the choice to non lcms colorspaces. Not that 
having a fallback to rgb32, means that the rgb32 colorspace have to be 
available in the library along with lab.

> > > Of course, even wet now inherits from
> > > KoLabColorSpaceTrait and ycbr doesn't, but doesn't compile either
> > > because of that.
> >
> > YCbCr is a bastard between a lcms colorspace and a non lcms colorspace.
> > Mainly because the only YCbCr profile I know are those of SUN, and as
> > long as krita is not a java application, we can't use them ;) I wanted to
> > create a "standard" YCbCr profiles using lcms, it should be easy, but the
> > 'advanced" part of lcms is a little bit hard to figure out ;)
>
> We could ask on openicc for a profile, or write the YCbCr colorspace in
> Jambi :-).
Having a function to create profiles for YCbCr would be even better, 
conversion from/to rgb is dependent on three parameters, most of the time the 
default value is used, but we never now.

-- 
--- Cyrille Berger ---
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