Re: alpha support for colors

[aaditya sood]

Hi,

 <joakim <at> verona.se> writes:

> 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)

IMO you're spot on. We'd want to do a composition of all the faces
that exist for a particular character, taking into account things like
alpha values.

I think a good use case is things like flymake error faces. I want my
error lines to be more "reddish" while still retaining the original
font lock highlighting.

>> 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.

:)

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

That is my intent. However I'd like to discuss some of the design
issues, or where to start hacking beforehand. This is to reduce the
complexity of merging into trunk at a future date.

regards
--
aaditya