Hi,

this is a request for comments on some changes I am considering to work on.

Concretely I'd like to change the way softproofing and gamut checking 
(SP/GC) is handled on the GUI side and in the pixelpipe as at the moment 
they are not very convenient IMHO. And being at that I'd also like to 
change the way how the display profile and display intent can be 
selected by the user.

With the current status I see the following issues:

A) SP/GC can only be activated by keyboard shortcuts (you need to 
remember those).

B) Only if the GUI of the "output profile" module is in focus you can 
see if SP/GC are active.

C) Selecting the softproofing profile is a per-image setting. You either 
need to select the profile individually for each image or you need to 
generate a preset/style which is automatically applied to images - 
inconvenient if you want to quickly test different profiles or different 
images.

D) As SP/GC are part of the "output profile" module, both actions happen 
late in the pixelpipe but not at the end - there are some modules after 
that (namely the channel mixer) which can render both actions useless.

E) SP/GC are done on Lab data. Very often the Lab values of dark shadows 
tend to be unbounded. The gamut checking functionality of lcms2 is very 
fussy and will mark those areas as out-of-gamut although in fact those 
values are not of a big concern once converted to RGB and clamped to the 
permissible range - the sheer level of false alarms tends to hide the 
real problems.

F) For the display profile and the display intent the same issues apply 
as under (C).



My idea is to do the following:

1) Find a way to activate SP/GC in a way similar as we do with 
over-/underexposure, i.e. we should have an activation button at the 
lower edge of the image pane (this addresses A and B). The button should 
allow to toggle the three display features 
(normal/softproof/gamut-check) and change its appearance accordingly, like

[ ] .. [S] .. [G]


2) Right clicking the button should open a menu to select the 
softproofing profile as well as the display profile and display intent 
(this should address C and F). One of the combobox options for display 
profile and display intent could be "image settings" to keep 
compatibility with legacy history stacks (similar to what we do in the 
"export selected" panel). It's understood that on systems with a proper 
color management setup, manually changing the display profile is 
normally not needed.

3) SP/GC functionality in the pixelpipe should be moved into a separate 
hidden module very much at the end of the pixelpipe. We would deal with 
this in a similar  way as we handle over-/underexposure. We would apply 
SP/GC on the final output RGB data rather than the intermediate Lab 
color space (this addresses D and E).

That's the idea. Any comments, concerns and proposals?

Best wishes

Ulrich


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