Re: Question about display engine

[Eli Zaretskii]

> Cc: address@hidden, address@hidden
> From: martin rudalics <address@hidden>
> Date: Sat, 7 Sep 2019 08:52:56 +0200
> 
> When I set the :extend attribute of the default face, everything seems
> to work as expected.  The problem is that if, in the earlier mentioned,
> 
>        /* Update the faces id and extend.  */
>        it->face_id = new_face_id;
> 
>        if (FACE_EXTENSIBLE_P (new_face))
>          it->extend_face_id = new_face_id;
> 
> no extensible new face is found, the assignment fails and the old
> region background stays in place for the rest of the window.  So it
> seems that you have to make sure that _some_ default background is
> always assigned here in case no face applied has the :extend attribute
> set.

The default face should always be merged into the face used for line
extension, that goes without saying.