Re: "Final" version of tty child frames

[Eli Zaretskii]

> Date: Tue, 14 Jan 2025 18:33:01 +0100
> Cc: gerd.moellmann@gmail.com, jared@finder.org, emacs-devel@gnu.org
> From: martin rudalics <rudalics@gmx.at>
> 
> I'm in a base (underlying, normal) frame which is partially covered by a
> child frame.  With 'line-beginning-position' 686 and 'line-end-position'
> 759 and point at 724 I try to move point to position 725 which is the
> first position on that row covered by the child frame.
> 
> In set_cursor_from_row at
> 
>    if (!((row->reversed_p ? glyph > glyphs_end : glyph < glyphs_end)
>       && BUFFERP (glyph->object) && glyph->charpos == pt_old)
>        && !(bpos_max <= pt_old && pt_old <= bpos_covered))
> 
> I have x = 39 which is the expected value 725 - 686 and I would like it.
> But that check fails (or better "succeeds") because of

If set_cursor_from_row wasn't taught about child frames on TTY, all
hell will break loose, because that function doesn't check that the
glyphs belong to the same window/frame.  The 'struct glyph' now
includes the pointer to the frame from which the glyph came, so these
tests should be augmented to have the loop stop when it bumps into a
glyph from another frame.