Verticality and future of display engine and lines (bis) [Was: Re: RTL lines]

[Alexandre Garreau]

I just coincidentally ended on a webpage with a vertical script (which 
surprisingly to me displayed correctly under firefox):

https://fr.wikipedia.org/wiki/Sakhaline

However copypasting that into emacs, or viewing the page with Eww makes 
that text incorrectly LTR.  Hence I suppose emacs doesn’t yet support 
viewing and editing TTB/BBT text as such…

Have there been an attempt at that? Anyway, what would a such change 
require and how much would it overturn the current display engine? would a 
solution to that problem possibly cover up with the problem I raised in 
the other almost-homonym thread?

Le lundi 18 octobre 2021, 14:40:42 CEST Alexandre Garreau a écrit :
> Is there a var to make any line whose first either rtl or ltr char is
> RTL be displayed RTL (so for instance an org-mode definition list (with
> ::) would be displayed RTL with the bullets at right, if the defining
> terms (at the beginning, just after the */+/-/etc.) are in
> arabic/hebrew/etc.)?
> 
> Another idea I have is is there a way to do that per-paragraph (for
> instance for a defun that would use a such language)?
> 
> and arbitrarily (for direction-agnostic languages such as some extreme-
> oriental ones)?
> 
> and does emacs support TTB/BTT (top to bottom, bottom to top), because I
> feel that would be a better use of human peripheral vision and physical
> ergonomical limit of line-length?