bug#57607: Feature request: Use the character cell on bottom-right corner of a terminal

[Akib Azmain Turja via "Bug reports for GNU Emacs, the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>]

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Gerd Möllmann <gerd.moellmann@gmail.com> writes:

> Akib Azmain Turja <akib@disroot.org> writes:
>
>> Gerd Möllmann <gerd.moellmann@gmail.com> writes:
>>
>> I mean, what files to change in order to do this?  I think it's
>> tty_write_glyphs and tty_write_glyphs_with_face in term.c.
>
> Are you interested in implementing something?  You could re-open this
> bug then, no problem.  Or are you maybe just evaluating if you'd like to
> do it?  Please give a hint.

Yes, I'm interested, because I think it would help me understand how
Emacs renders text in terminal, which would help me to implement child
frame in terminal.  But I don't have the time to do it right now.  I
hope I can start doing this by late October.

>
> The places you mention sound right.  It's probably all in term.c.  But
> I'd like to add, that in principle all places writing to the terminal
> have to be checked at least.
>
> And corner cases have to be taken into consideration :-).  Pulling
> something out of thin air: What happens if we write RGRG to the
> bottom-right corner, where R is one red char, and G is 1 green char,
> say.

I think you meant the following in Bash:

--8<---------------cut here---------------start------------->8---
printf "%$((COLUMNS - 4))s\e[31mr\e[32mg\e7\e[32mg\e8\e[@\e[31mr\e[m" "" ; sleep 1 ; printf '\n'
--8<---------------cut here---------------end--------------->8---

And it works on St, Kitty, Coterm, Term, etc.

>
> And maybe we have to check for characters that are more than 1 column
> wide?  I don't remember something like that from when I last worked in
> this area, but I'd check what the situation is nowadays.
>
> That's all I can say without studying the code more in detail, which I'm
> trying to avoid :-).
>

-- 
Akib Azmain Turja

Find me on Mastodon at @akib@hostux.social.

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