Re: alpha support for colors

[joakim@verona.se]

aaditya sood <aaditya@sood.net.in> writes:

> Chong Yidong <cyd <at> gnu.org> writes:
>
>> 
>> aaditya sood <aaditya <at> sood.net.in> writes:
>> 
>> > Does emacs support alpha blending on colors on faces? In particular 
>> > can I specify colors in ARGB format?
>> 
>> No.
>
> Ok, I guess my googling wasn't in vain. 
>
> Are people interested in this capability? I'm interested in working on this 
> feature, with (hopefully) some guidance from emacs developers.
>
> If I wanted to start work on it:
>
> 1. Where should I begin?

What would the interface be? So, lets say you want an alpha component
for the foreground. try adding that somewhere in the face descriptor,
just temporarily in your own experimental branch. Then, how do you
propose to add the faces together? Let's say you add a function
blend-faces, that adds the colours together, taking in consideration the
alpha value, and creates a new face. Then you use this function to do
what you want.

(I'm just guessing what you want to do, so my advice is probably pretty lame)

> 2. Is it even do-able in terms of complexity, or will it touch the fabled and 
>     scary redisplay engine?

Maybe, but it's not THAT scary. It's actually pretty cool when you get
to understand it a little bit.

>
> What do people think?
>
> I've have some experience with C and elisp, but mostly an emacs user 
> till date. Perhaps my chance to contribute back.

My suggestion is to make a separate branch where you hack a bit to try
to gauge the complexity.

> regards
> --
> aaditya
>
>
>

-- 
Joakim Verona