Painting on selections and selection masks

[Boudewijn Rempt]

On Saturday 29 October 2011 Oct, Cyrille Berger Skott wrote:
> On Saturday 29 October 2011, Boudewijn Rempt wrote:
> > On Saturday 29 October 2011 Oct, Cyrille Berger Skott wrote:
> > > There is no problem for Krita to handle pre-multiplied colorspaces, 
> > > since a premultiplied RGBA, is actually defined as (a*R, a*G, a*B, a).
> > > And if there is such an assumption, it is a bug ;) It would mean that
> > > somewhere Krita makes assumption about the color data.
> > 
> > It's either a bug, or a design decision that permeates all our code. Either
> > way, it's not feasible to refactor, redesign or fix for 2.4.
> 
> Do we even have any attempt at a premultiplied color space ? That is the first 
> time I hear it... If so, can I have a look at the code ?

No, but in fact, the gray-without alpha colorspace could be seen as a colorspace with pre-multiplied alpha. But there's no way it's going to work.

> 
> > * we are talking about a 2 year old critical bug
> > * we are one month away from the final release
> > * we have tried the following solutions:
> > 	* fix the gray colorspace
> > 	* fix he alpha colorspace
> > 	* special case dab creation
> > 	* patch over the difference in design assumptions inside KisSelection
> > * everything failed except the last attempt, which has its disadvantages
> > * we cannot do a big refactoring of pigment or all of Krita in time for the
> > release.

> Sure... So what did you expect from your email ? Do you need help fixing the 
> patches ?

No, I can do that myself, the changes are pretty simple, with the only tricky bit being the extent calculation of KisPixelSelection after changing it from alpha to gray + alpha.

What I had hoped for was that people would have tried to a) understand what I was trying to do instead of immediately just opposing it b) see whether there is any other way of solving the issue.

To me, it is clear that there is no other solution: we cannot realistically fix pigment to use multi-channel colorspaces as masks and we cannot fix krita to work with colorspaces without an alpha channel.

And I still want to be able to release Krita 2.4 this year -- although I heard noises from Boemann that Words might be holding up the release because of some deep style management issues.

-- 
Boudewijn Rempt
http://www.valdyas.org, http://www.krita.org, http://www.boudewijnrempt.nl