Cyrille Berger wrote:
> On Tuesday 22 September 2009, Matthew Woehlke wrote:
>> Cyrille Berger wrote:
>>> On Tuesday 22 September 2009, Sven Langkamp wrote:
>>>> What would a 'color space change' mask be? Is there a case were it's
>>>> needed to convert the colorspace manually with a mask?
>>> Yes. Two cases actually, tone-mapping and raw. For raw, some of the
>>> algorithms can be applied on a raw colorspace (well curves), some other
>>> would need to be applied on a RGB one.
>> I thought we'd said we wouldn't have a "RAW" colorspace, just va16¹?
> That's not what the wiki says [1].

Really?

"Another option is to ignore the problem, accept that filters will not
work correctly on bayer data, and import RAW directly into a 16-bit
single channel (i.e. 'grayscale') layer. /At time of writing, this
seemed to be the preferred option/ [...]" (emphasis added)

...and I certainly seem to recall that was the preferred solution. Much
less special-casing, for one.

> [1]
> http://wiki.koffice.org/index.php?title=Krita/Direct_RAW_Editing#A_Dedicated_Colorspace

>> You
>> can't debayer as a mask² anyway, it's a specialized convolution filter.
> Why not ?

You conveniently snipped that part of my previous message:

>> (² at least I think not; wouldn't a cs-conversion mask normally be
>> necessarily 1:1?)

So... can a mask¹ implement a convolution filter, or a filter with
configurable parameters? (Bayer -> other cs is not a 1:1 filter like
most cs conversions, it is a convolution filter³, and there are multiple
choices of algorithm (and maybe even parameters?).)

(³ ...and not even a 'straight' convolution filter. Even disregarding
that you use different formulae depending on what channel the pixel
represents, you have different formulae for the edges as well.)

(¹ Maybe the problem is I don't understand what a "mask" is in krita
internals. When I hear "mask" I think an extra alpha channel that is
used to control what parts of a layer are blended, i.e. same as how it
is used in svg terminology. Clearly the "mask" you are talking about is
something completely different. It sounds more like a filter that...
well, ignores masks. Which is confusing.)