Re: "Final" version of tty child frames

[Eli Zaretskii]

> From: Gerd Möllmann <gerd.moellmann@gmail.com>
> Cc: rudalics@gmx.at,  jared@finder.org,  emacs-devel@gnu.org
> Date: Fri, 17 Jan 2025 09:50:40 +0100
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> >> From: Gerd Möllmann <gerd.moellmann@gmail.com>
> >> Cc: rudalics@gmx.at,  jared@finder.org,  emacs-devel@gnu.org
> >> Date: Fri, 17 Jan 2025 08:50:58 +0100
> >> 
> >> There might be another problem. Feng Shu, the author of Posframe,
> >> reported a problem with child frames over Chinese text at some point:
> >> 
> >>   https://yhetil.org/emacs-devel/m25xpji82g.fsf@gmail.com/
> >> 
> >> In short, this handles the case that a child frame overlaps a
> >> double-width character, in the sense that one half of the displayed
> >> character is outside of the child frame, and the other half is under the
> >> child frame.
> >
> > Didn't you already fix that problem in the past, when child frames on
> > TTYs were first introduced?
> >
> > What should happen in this case is that we don't show the double-width
> > character at all.
> 
> Yes it's fixed, and the fix is the problem. It modifies the root's
> current matrix outside of the area that a child occupies, by changing
> glyphs to padding glyphs.

I guess the child's matrix should save and restore mote that it
overwrites?