bug#50660: 28.0.50; Text artifacting when the cursor moves over text under mouse face that originally displayed a box

[Eli Zaretskii]

> From: Po Lu <luangruo@yahoo.com>
> Cc: larsi@gnus.org,  50660@debbugs.gnu.org
> Date: Sat, 16 Oct 2021 14:16:12 +0800
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> > I don't think I follow: what is "the original font" in this context?
> > And when you say "shouldn't s->font be", do you mean what it should be
> > before or after the processing in fill_glyph_string?
> 
> I meant what it should be after the processing, and by "the original
> font", I meant the font of the original face, that was used to calculate
> the metrics of the glyphs.

FACE_FOR_CHAR will get you the face with the correct font, and calling
get_glyph_face_and_encoding after that will produce the glyph codes
from that font.  So that's exactly why I commented why your additional
code must be before the loop that produces the glyph codes (inside
get_glyph_face_and_encoding).