The future of selections and masks in Krita

[Casper Boemann]

Hi

Now that our personas are done it's time for the next step in usability for 
Krita 2.0, and what's pressing is the future of selections and masks.

We have had some discussion as to what we shall do, and the way to solve this 
is to do some usability work.

The question we need to ask ourselves first is: What does the user want to do?

On a tripod Arthur took 3 pictures of the same target with different exposures 
and now he wants to blend them together, by taking the best parts of each 
photo. He wants to do this blending in a non-destructive manner so he can 
experiment. He needs fine control over where the blending occours and by how 
much, so access to modifying alphas for blending on a per pixel basis is very 
important.

Arthur uses selections to paint a selection around an item and want to reuse 
that selection on different layers to create the different types of blending. 
Comparing that to todays functionality of a selection per layer, we conclude 
that todays functionality might be too complex. Arthur wants the concept of 
selection to be easy understandable, as he doesn't care to learn 
unconventional things even if in the end they might turn out to be more 
powerfull. Ben and Claire might be a bit more willing in this regard, but for 
all users it's a question of pro and con. How much do you gain by a 
functionality that confuses you. So I think it's safe to say they all want it 
to be easy to understand and use.

Another use case against per-layer selection is when the user has created a 
selection on the wrong layer (which happens quite often). It will be very 
nice to be able to just switch layer and have the selection following along.

Arthur and Ben definitely want to be able to move a selection around without 
affecting the underlying image. We even have a bug report for that.

Arthur and Ben want to be able to select something, copy, move, and transform 
the selection, and then to do that all over again. Sometimes Arthur and Ben 
want to modify some pixels in between.

The solution Bart, Cyrille, Thomas and I have come up with is to have:
  - a single global selection
  - display masks per layer
  - abillity to convert selection to mask and back
  - ability to edit the mask (it's just an alpha colorspace after all)

-- 
best regards / venlig hilsen
Casper Boemann