color: Add enum definitions of code points
Enumerations for color primaries and transfer function as per discussion in wayland-protocols/!14.
The color primaries enum tries to use common names of color spaces, where they exist. It has no equivalent of the following H273 code points:
-
smpte_240m
(7) is a variant equal tontsc
(6). -
ebu3213
(22) is apparently revoked in a newer version of H273 (that I was not able to find): https://github.com/AOMediaCodec/libavif/issues/879, which results in a defined color space with no recognized name. Since it is not used anywhere it is not a useful color space. The real ebu3213 is equivalent topal
(5) and would not be included separately likesmpte_240m
.
A couple of color spaces could instead be reasonably named after ITU specs:
-
srgb
->bt709
-
pal_m
->bt407
-
pal
->bt601-652
-
ntsc
->bt601-525
The transfer function enumeration is mostly taken from !36 (closed). H273 references have been added.
Naming of the enumerations and related methods is probably worthy of a bike-shed. I didn't want to use cicp
given this isn't strictly H237, so the protocol now refers to these values as "named primaries" and "named transfer functions".