Re: alpha support for colors

[Stephen J. Turnbull]

Eli Zaretskii writes:

 > What do you mean by "composition of all the faces"?  Why "all"?

I suspect aaditya is thinking in terms of bitmap composition
operations on graphics layers, not Emacs faces.

So he'd like to put an overlay on some text, give that overlay a 'face
property of '(+ red), and turn all the blue text in the overlay to
violet (the RGB sum of #F00 and #00F == #F0F).