color profile aware color adjustment

[Bart Coppens]

(Mails arriving just before I go to bed, bah ;-)

On Friday 06 January 2006 02:50, Larry Marso wrote:
> Boudewijn and I discussed the potential utility of Krita to work on
> curves for the channels of LAB colorspace, once the color
> profile-aware color adjustment tool (temporarily out of CVS) is
> restored to the build sources.
Apparently, this is fixed already in SVN now.

> One thing I don't know is if you can resize the curves widget.
> Manipulations of curves in the A and B channels, in particular, often
> require considerable precision in a small area around the center
> point.  The ability to significantly enlarge the curves widget would
> have great value.
You can resize it, but since internally the code actually just draws the 
histogram on a pixmap, it will only scale the pixmap, which can lead to ugly 
looking drawings. This could probably be fixed, though, by giving a size for 
the histogram and then manually drawing bars.

> Boudewijn and I also discussed the Photoshop "color picker" tool which
> permits you to select a radius over which values are averaged.  In
I had a look at how to get this specific thing into 1.5, and it would be 
possible. There is one slight problem though: the colorspaces have a 
mixColors function, which I could use for it, but it requires that the sum of 
the weight of all pixels taken into consideration is 255. This means (quick 
calculation before bedtime, errors likely) a maximum radius of 9 (9.0270 it 
seems?, but we round down) pixels. Would this suffice?

> addition, Photoshop lets you click on multiple points with values
> you're focusing on for manipulation by curves.  You can click on and
> save multiple averages, which appear one atop another.  Then, when you
> manipulate the curves, a column appears alongside those saved
> averages, and you can watch how your curve manipulations change the
> average values.
I'm a bit puzzled by how this can be presented in a visually pleasing and nice 
way. Currently all I can think of looks bad, but that might be because I'm 
supposed to be fast asleep by now... ;-)

Bart Coppens