Re: VIM-6 - rightleft redisplay

["David Harrison Jr." <david at motionrealityinc dot com>]

Nadim Shaikli wrote:

> On Fri, 07 Dec 2001 08:40:03 -0500
> "David Harrison Jr." <david at motionrealityinc dot com> wrote:
>
> > Nadim Shaikli wrote:
> >
> > > Well, I would suggest downloading our work-in-progress code,
> > >
> > >  http://www.arabeyes.org/cgi-bin/cvsweb/arabeyes/vim
> > > -or-
> > >  http://www.arabeyes.org/~nadim/vim/vim-shaping.tar.gz
> > Ok.  I've used it awhile now.  Lots of screen refresh problems when
> > you are in an ISO-8859-x type of setup.
>
> Actually seems like the refresh is there irrespective of which mode or
> setting you are in (ie. screen_line seems to redisplay with each new
> character even in "default" english).
>
> > The Arabic input is interesting.  I press 'q','w' which show a slightly 
> > different set of characters than typing 'q', ' ', 'w'.  I press CTRL-L 
> > and the "combined" 'q''w' sequence is indeed drawn differently.
> >
> > Hmmm,  I'll take a closer look...
>
> I've solved most of the known problems, shaping is pretty functional
> in the various different settings (including CTRL-L).  As of now, there
> are no known issues regarding shaping stand-alone (note - "as of now" :-)
>
> Here's what's left (as I see it) regarding Arabic Shaping and support:
...

> 2. Fix the screen_line (in screen.c) to redisplay characters from
>    right-to-left in rightleft mode.

This has me thinking that other languages could benefit from a 
generalization of this part of the code.  Certain Asian texts are shown 
vertically, thus we may (eventually) have a set of options that allow us 
to have the main flow of text be either vertical or horizontal.   Within 
each of these two modes the text could be shown one way, or the other 
"reversed" way (i.e. top-to-bottom or bottom-to-top).

I can't even imagine how frustrating it must be for a Vim user that 
reads vertical text to be forced to read in a horizontal direction (from 
within Vim).  Maybe rotating the screen 90 degrees would be the easiest 
thing to do... problem solved!  :-)

> Please note that the links noted above (in previous post) have been
> updated and I highly recommend and encourage re-syncing.

I re-synced.  The main redraw problems are now gone.
I notice that when I switch back and forth between rightleft and 
norightleft mode, different Arabic "shaped words" will be displayed 
(they are the same word, but displayed differently).  I assume that they 
are only correct when in rightleft mode.

> Thanks for your help and interest.

I don't think I was of any help, but I'm definitely interested in 
generalizing Vim's code to handle new languages.

--David H. Jr.