Re: Question about display engine

[Eli Zaretskii]

> Date: Wed, 28 Aug 2019 18:31:42 +0200
> From: Ergus <address@hidden>
> Cc: Eli Zaretskii <address@hidden>, address@hidden
> 
> Any way my question comes from 2 frequent use cases I don't know what's
> the expected behavior:
> 
> 1) Base face sets background and extend; and face sets only background.

The background of the base face will be extended.

> 2) Base face sets extend but not background; and face sets both.

The background of the face will be extended.

> in what condition the :extend attribute goes to the merged face? Always?
> when in base_face? When in face?

The :extend attribute determines whether the background color of the
face with that attribute does or doesn't get merged into the "merged
face" to be used by the iterator.