Maybe SolidColorType instead if RawColorType?

"Solid" would imply to me that there is no alpha, but an RGBA 4-tuple is valid there

BaseColorType?

The other option that occurs to me, though it is slightly more complicated, but perhaps in a useful way:

RGBColorType=str|tuple[float,float,float]RGBAColorType=str|tuple[float,float,float,float]|tuple[RGBColorType,float]|tuple[tuple[float,float,float,float],float]ColorType=RGBColorType|RGBAColorType

Not so happy about the last leg of RGBA needing to be added (not as clean as I would like, but nottoo bad.

Both need str, not only for named colors (which would actually almost exclusively be the RGB, not RGBA), but also for hex colors ("#RRGGBB(AA)") and while in some sense those are a different "type", we pass them as strings and don't have a good way of telling the typechecker the difference satisfactorily.

(The exception for named colors that have non-opaque alpha is"none", I'm pretty sure all others have no alpha component inherently)

(I wrote it out here with| notation, which is py3.10+ but more readable, would have to useUnion[..., ...] in this context since the type alias is actually potentially evaluated at runtime (not imported by default, but importable; unlike type annotations which are not directly evaluated))

There is no place where we actually use the RGB/RGBA specific types, but string is valid for either, so wecould specify if it were relevant.

Essentially I neededa name to organize the thought of "2-tuple of this type plus float alpha"

The original called it "RawColorType" but I didn't like that name and chose to go with something at least semantically meaningful as a distinction.