Re: Question about display engine

[Eli Zaretskii]

> Date: Wed, 7 Aug 2019 17:32:20 +0200
> From: Ergus <address@hidden>
> Cc: address@hidden
> 
> After thinking on that a little bit more since yesterday; maybe it is
> possible to add another basic face for the rest of the line. That face
> will be merged with the previous face as in the example code, so if it
> specifies :underline then merging should work as specified; else, it
> will just use the :underline from the latest glyph.

Such a face will not be a fixed face, it will have to be recomputed
whenever the face of the text changes, right?  E.g., if the face of
the text specifies some color, you'd want this additional face to have
the same colors, right?

So it doesn't seem to be a face that can be customized in the usual
sense.  We could let the users specify face attributes they don't want
to see in face extension, though.