BOGL bterm

[Edmund GRIMLEY EVANS <edmundo@rano.org>]

Here are the instructions for using bterm. I'd like to hear from anyone
who has time to try this, but I'm away from computers from April 8 till
April 15, so I won't reply during that period. I'll probably
unsubscribe debian-boot, so please copy relevant messages to me.

At present libutf8 isn't in CVS. Instead, get it from
http://www.rano.org/tmp/bogl-libutf8.tar.gz. And I haven't made the
file UTF-8-test; instead do echo -e "\304\211" to get a 'c' with hat,
for example.

And don't let this distract from getting potato ready!


System requirements

I don't know what the requirements are, but this is what I'm using:
kernel 2.2.14, which I compiled myself and configured to use the
framebuffer console. My /etc/lilo.conf contains the line "vga=771". I
have a cheap motherboard with a Cyrix "i686" processor and on-board
graphics using SiS 5597/8. When the system starts I get a penguin in
the top left of the screen and a text console with 100 columns. I don't
have the bandwidth to dist-upgrade, but I keep things like libc6 and
gcc up-to-date with potato. When I run BOGL I'm using the code in
bogl-pcfb.c with 8 bpp, I think.


The code

If you're not already familiar with boot-floppies, you probably
shouldn't be reading this, but the basic instructions are: install the
latest boot-floppies using apt-get, so that you get other required
packages too, then look in /usr/src/boot-floppies/README-CVS for
instructions on how to get the very latest version from CVS.


Fonts

Get Markus Kuhn's fixed-width BDF fonts with UCS encoding:

http://www.cl.cam.ac.uk/~mgk25/download/ucs-fonts.tar.gz
http://www.cl.cam.ac.uk/~mgk25/download/ucs-fonts-asian.tar.gz

These fonts are also useful for a UTF-8 xterm. I used 9x18.bdf and
18x18ja.bdf for testing.


Compiling

$ cd /usr/src/boot-floppies/utilities/libutf8
$ make
$ cd /usr/src/boot-floppies/utilities/bogl
$ make bdftobogl bterm
$ ./mergebdf .../9x18.bdf .../18x18ja.bdf > font.bdf
$ ./bdftobogl -b font.bdf > font.bgf

For screen-oriented programs you need a terminfo entry for bterm. Do
the following to check you don't already have an entry for bterm, then
make one in the user's ~/.terminfo/. Either make sure you run bterm as
the same user as you ran tic, or run tic as root to make a terminfo
entry in the system terminfo directory.

$ infocmp bterm
$ tic bterm.ti
$ infocmp bterm


Running

Go to a text console, as I don't know what effect this might have on X,
and:

$ cd /usr/src/boot-floppies/utilities/bogl
$ export LD_PRELOAD=/usr/src/boot-floppies/utilities/libutf8/libutf8_plug.so
$ export LC_CTYPE=eo.UTF-8
$ ldd bterm
$ ./bterm -f font.bgf

The ldd is to check that you didn't mistype the LD_PRELOAD bit; you
should see that bterm is linked with libutf8_plug.so. If it isn't it
won't work at all but the error won't be very helpful.

You should get a new text console with a disgusting black-on-white
colour scheme. You can check that UTF-8 works with:

$ cat UTF-8-test


Screen handling

Bterm understands a tiny subset of the control sequences that xterm
understands, but sufficient, I hope, for slang, curses and GNU
Readline. (If you want vt100 emulation, you can always run GNU Screen.)
You can test a program's ability to work in a bterm by running it in a
UTF-8 xterm with export TERM=bterm. If you notice any incompatibilites
between bterm and a UTF-8 xterm, please tell me.

For instructions on how to get a UTF-8 xterm, see:
ftp://ftp.ilog.fr/pub/Users/haible/utf8/Unicode-HOWTO.html


Slang and newt

I have patched slang and newt to (partially) work in UTF-8. Get the
code from:

http://www.rano.org/mutt/slang-1.4.0-ege5.diff 
http://www.rano.org/mutt/newt-0.50-5.3-ege1.diff 

Here's what to do (there's a fixed relative path to ../slang14 in
newt-0.50/Makefile; sorry about that):

$ bzcat /usr/local/src/slang/slang-1.4.0.tar.bz2 | tar xf -
$ mv -i slang-1.4.0 slang14
$ cd slang14
$ patch -p0 < ~/slang-1.4.0-ege5.diff
$ ./configure && make
$ cd ..

$ tar xzf newt_0.50.orig.tar.gz 
$ cd newt-0.50
$ zcat newt_0.50-5.3.diff.gz | patch -p1
$ patch -p1 < newt-0.50-5.3-ege1.diff
$ # Using a UTF-8 editor, change the messages in test.c and testgrid.c
  # to include lots of exotic characters.
$ ./configure && make testing testgrid

Now, in the bterm (or a UTF-8 xterm):

$ newt-0.25/testing
$ newt-0.25/testgrid


Internationalised boot-floppies

I haven't tried this yet, but I intend to: Convert the PO files to
UTF-8 using the command iconv in a script. Recompile dbootstrap with
language chooser against the patched slang and newt. Include bterm and
a suitable font in root.bin and modify /etc/init.d/ to run dbootstrap
in a bterm. Make sure the kernel on the rescue floppy has a
framebuffer. Et voila, maybe.

There are probably bugs in the patched slang and newt, because they're
not very much tested yet. If you can identify a bug, please send me
details.