Re: Debian installer and braille

[Samuel Thibault <samuel.thibault@ens-lyon.org>]

(Cc-ing Dave Mielke)

Frans Pop, le Sat 31 May 2008 13:48:32 +0200, a écrit :
> Hmm. Just noticed these in my logcheck mail:

These just come from the fake XWindow driver.

> brltty[11186]: Could not load a braille font for charset ISO8859-1
> brltty[11186]: Could not load a braille font for charset JISX0208.1983-0
> brltty[11186]: Could not load a braille font for charset KSC5601.1987-0
> brltty[11186]: Could not load a braille font for charset GB2312.1980-0
> brltty[11186]: Could not load a braille font for charset JISX0201.1976-0

Well, actually these are spurious: a braille font doesn't need to cover
something else than U+2800-U+28FF, which these charset don't cover

> brltty[11186]: Could not load a unicode font for charset KSC5601.1987-0
> brltty[11186]: Could not load a unicode font for charset GB2312.1980-0

And these aren't really a problem since the XWindow fake braille driver
doesn't support wide characters.

I'll try to seem how to filter them out properly.

> Do we need to add something in the installer to support languages
> other than English? Could CJK languages (Chinese, Japanese, Korean) be
> supported as well in theory?

That question is actually not related to what is above :)

There are ways to support CJK on bare linux text console by using
specialized fonts, but it is quite oddly done (brltty needs to be
explicitely configured for this since there is no real proper way to
autodetect it, etc.).  Currently, the debian installer uses bterm
instead, but that is not accessible, see

http://lists.debian.org/debian-boot/2006/03/msg01035.html

Nothing happened about it.  I hadn't pushed more pressure because proper
Unicode support for CJK only happened recently in brltty.  But actually
we now have it in 3.10, so maybe we can think about it again.  Trying to
sum it up:

- brltty currently only works with a bare linux console, that's why
  brltty-udeb currently automatically disables the framebuffer.
- yes, we could implement a frontend that directly talks to the braille
  device, but we shouldn't do that unless it is synchronized with a
  frontend shown on the real screen, since blind people also need to
  work with sighted people, and having two different non-synced views
  would be a mess.
- we could define a /dev file which looks much like /dev/vcs*, except
  that it provides a unicode view instead of the VGA-crippled view of
  /dev/vcs*.  That, however, is not restricted to Debian, of course.

Samuel