* Store scene linear to XYZ conversion matrix in each blend file, along
with the colorspace name. The matrix is the source of truth. The name
is currently only used for error logging about unknown color spaces.
* Add Working Space option in color management panel, to change the
working space for the entire blend file. Changing this will pop up
a dialog, with a default enabled option to convert all colors in
the blend file to the new working space. Note this is necessarily only
an approximation.
* Link and append automatically converts to the color space of the main
open blend file.
* There is builtin support for Rec.709, Rec.2020 and ACEScg working spaces,
in addition to the working space of custom OpenColorIO configs.
* Undo of working space for linked datablocks isn't quite correct when going
to a smaller gamut working space. This can be fixed by reloading the file
so the linked datablocks are reloaded.
Compatibility with blend files saved with a custom OpenColorIO config
is tricky, as we can not detect this.
* We assume that if the blend file has no information about the scene
linear color space, it is the default one from the active OCIO config.
And the same for any blend files linked or appended. This is effectively
the same behavior as before.
* Now that there is a warning when color spaces are missing, it is more
likely that a user will notice something is wrong and only save the
blend file with the correct config active.
* As no automatic working space conversion happens on file load, there is
an opportunity to correct things by changing the working space with
"Convert Colors" disabled. This can also be scripted for all blend files
in a project.
Ref #144911
Pull Request: https://projects.blender.org/blender/blender/pulls/145476
6a083a5464