Re: Question about display engine

[Eli Zaretskii]

> Cc: address@hidden
> From: martin rudalics <address@hidden>
> Date: Tue, 3 Sep 2019 10:45:18 +0200
> 
>  > I don't think I understand why you are talking about face pointers.
>  > The iterator doesn't keep any face pointers, it keeps face IDs (which
>  > allow to obtain the face pointer, when needed, by using FACE_FROM_ID).
>  >
>  > So all you need is to have another face ID member in the iterator, to
>  > be used for extending past EOL; depending on how the :extend bits are
>  > set, that face ID may or may not be identical to the "normal" face ID,
>  > the one we have now and use for buffer text.
> 
> But a face ID is only available after realizing a face.  With a lazy
> approach there might be no realized face yet and the iterator would
> realize that face on the fly.

What do you call "realize a face", exactly, and why do you think it is
so expensive as to justify doing that lazily?