[BRLTTY] FYI: HandyTech Modular Evolution 88 and Linux console size (88x42)

[Mario Lang]

Sebastian Humenda <shumenda at gmx.de> writes:

> Mario Lang <mlang at delysid.org> wrote on Di, Mai 04, 2010 at 12:56:36 +0200:
>>I recently managed to configure my Linux console to have 88 columns
>>(and 42 lines).  Since the display is continuous, you can then use
>>all the width of your display during your work on the console.
> [...]
>>The trick is to set a framebuffer resolution and a certain font size
>>which results in the number of columns you desire.  In my case, I
>>used 800x600 as a starting-point with fbset, and then issued

> How do you find out which resolution is the fitting one?

As explained above, you will have to do some simple math and experimentation.
First of all, the typical console font widths available are 8, 10, 12,
14 and 16 pixels.  If you have a specific target line width,
like in my case 88, you will have to find the best match between
the font widths (in pixles) above and the typical screen resolutions.
Just as an example, if I used 1600x1200 as framebuffer resolution,
I would need a 18-pixel wide font to achieve 88 text columns
per line.  There are (to my knowledge) no such fonts, so they
would need to be constructed first.  Experiment
with the modes your framebuffer driver/card supports well.
For this it can be helpful to have sighted assistance because
in some corner cases, the display might end up being scrambled which
you may not notice.  If you aim for a configuration which is also
usable by sighted coworkers (I always do) these initial tests
will help you to narrow down your options.

> Are changes after a reboot gone,

fbset and manually loaded fonts are gone after a reboot, you will
have to make them persist by editing some files in /etc once you
experimentally found a configuration which you like.

> do I need this as a kernel parameter?

Depending on your framebuffer driver, you can configure some
aspects of the framebuffer resolution via a kernel parameter.
I did not do this, I use fbset directly during the boot process.

> Which modes are available?

/etc/fb.modes is a list of some well-known modes.
The actual available modes will depend on the combination
of your graphics card and your monitor I guess.

>>"fbset -xres 704" which results in 704 pixel width which
>>divided by 8 (font width) results in 88 characters per line.
>>After loading a 14x8 console font, I have 88x42 text mode, which
>>works very nicely with this 88 cell display.

> How do I load such a font?

On my Debian system, I put

FONT="Lat15-Terminus14.psf.gz brl-14.psf.gz"

into the file /etc/default/console-setup.

I also installed the packages console-terminus and console-braille
which make the mentioned font files available in /usr/share/consolefonts/.

Note that the brl-14.psf.gz entry is not strictly necessary, but
very nice to have since it makes Unicode braille characters display
correctly in braille and on screen.

>>Unfortunately, to achieve this (as far as I know) you
>>have to load a framebuffer driver for your graphics card.  In my
> # cat /proc/fb
> 0 inteldrmfb
> So the framebuffer is no problem, but currently I have 170 characters, 160
> would be nicer (or even 120).

I personally dislike consoles with much more than 100 characters
because the point of a >40 cell display is to make
horizontal scrolling unnecessary.  With 160 column
consoles, I have to do that again and kind of loose most
of the benefit of a big display.

> How do I find out how to achieve this?

What are you exactly trying to achieve? :-)  What size does
your braille display have?

-- 
CYa,
  ⡍⠁⠗⠊⠕