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

[Alexandre Garreau]

Le jeudi 28 octobre 2021, 11:23:58 CEST Eli Zaretskii a écrit :
> > From: Alexandre Garreau <galex-713@galex-713.eu>
> > Cc: Eli Zaretskii <eliz@gnu.org>
> > Date: Thu, 28 Oct 2021 09:12:38 +0200
> > 
> > > I guess you are unaware, or perhaps forgot, that the display engine
> > > itself scrolls the window when it finds that necessary.
> > 
> > oh… but still that’s a few functions right…? I hope… like “scroll
> > down”
> > and “scroll up” calls that should be conditionally changed to “scroll
> > forward” and “scroll backward”
> 
> I guess you think that scrolling, in whatever direction, is a simple
> business.  It isn't; what those "few functions" do has a lot of
> implicit assumptions, most of them will be wrong with the change of
> direction.  Someone(TM) will have to come up with the necessary logic
> that doesn't exist, and make it support all the scroll-related
> features we have, like scroll-step, scroll-conservatively,
> scroll-up/down-aggressively, scroll-preserve-screen-position, etc.
> And then the low-level code which scrolls the screen by moving pixels
> will have to be rethought as well.
> 
> > > > Did you really look at the screenshots? don’t you see all the
> > > > blank
> > > > between the lines?
> > > 
> > > I'm talking about what I see in my Emacs session where I read your
> > > email.  If any Emacs session displays that as you describe, that's
> > > either a font configuration problem or some rendering bug that isn't
> > > present in my build of Emacs.
> > 
> > But did you look at the screenshots? doesn’t your gnus support simple
> > and direct display of mime attachments?
> 
> (I don't use Gnus.)

Sorry, in the absence of user-agent I wrongly assumed.

> Of course, I looked at them.  Why do you ask?
> they look like display bugs to me, as I said.

Oh ok I wanted to be sure, because I wasn’t (since to me it didn’t), now 
I’m sure they can look like bugs.

But about the mongolian script (you looked at that screenshot too right?), 
how would you imagine it to be displayed, ideally? did what firefox did 
look like a display bug too, to you?

> > > and I'm not even sure I understand why would you like to
> > > do something like that.
> > 
> > I already said it was to make reading more comfortable without having
> > to lump from one part of the text to another, read, and yet again go
> > there to resume reading, so the direction of reading is always
> > consistent (and ideally to have even less jumping, one would need to
> > use boustrophedon as a script direction, but afaik no existing
> > software supports that)
> I cannot imagine it will be easy to read an RTL text that wasn't
> reordered for display.  You'd have to read it one character at a time,
> something that is extremely slow.

Oh yes indeed because when we learn to learn fast we learn to recognize 
words instead of characters.

But I guess you can get used to that (and somewhat faster than learning 
each word twice), otherwise boustrophedon wouldn’t have been a practical 
script direction to be used at first with many scripts (for instance greek 
and other more ancient scripts, at times where the direction of writing of 
occidental languages wasn’t fixed yet).

Supporting that, I actually can read latin mirrored, because I initially 
learnt to write in that sense (now I’m much slower at that than with 
normal writing, because I’ve come to read a lot more than to write, but it 
may be that in a couple decades I’ve growed faster at reading that sense), 
and I wouldn’t mind getting again more accustomed to it.  But I guess as 
that can’t be done efficiently in elisp, emacs is not made for that, since 
that’s no more than an esoteric usecase (we could also argue about the 
esoterism of the inclusion of many extinct scripts in unicode, and that 
they shouldn’t be supported (although ancient boustrophedonian greek 
script is not included, while it’s more recent than certain extinct 
ancient scripts that are included))