# [BRLTTY] Brltty and the latex-access project

Daniel Dalton d.dalton at iinet.net.au
Thu Jan 19 08:16:42 EST 2012

On Fri, Jan 13, 2012 at 09:43:39PM -0500, Dave Mielke wrote:
> >latex-access still a problem, i.e. cursor routing data? I believe
> >getting a translation which was the desired length i.e. the same length
> >as the Braille display in use was still a bit of a problem?
>
> I'd stopped at the point where we needed to settle on a protocol for passing
> data back and forth. It needs to support sending multiple values in both
> directions. What do you think about sending a set of lines, each in the form
> name=value, with a blank line at the end? So, for example, brltyt might send
> something like this to your software:
>
>    cursor=12
>    length=40

Hi,

Sorry for the delay, I've been out of town for a few days and not the
kind of thing I can really study through email via android :)

That sounds ok as far as I can tell.

How would the actual content be passed? i.e. the input line to the
latex-access translator and then of course output from the latex-access
translator to the display?

What data does my project need to send to brltty? I suppose the updated
cursor position once cursor routing works...
And brltty should tell latex-access the position of the cursor...?

Then would it be up to my project to provide brltty with a translation
of the desired length i.e. if the braille display is 40 cell then 40
Braille chars?

>    text=   utf-8 encoded characters which can be indented and contain blanks

I really don't know much about uf8 to be honest...

>
> Output from your software back to brltty would be the same, but, of course,
> with a different set of data. Is this approach okay?

Sounds pretty good to me.

> We'd need to decide how to deal with newlines in the input text, as well as
> with whatever braille dot combination looks like a newline in the output data.

MMMM. we didn't really have a translation for new line characters,
besides wouldn't this change across Braille codes, currently
latex-access is very stable with nemeth and relatively stable with ueb
though there are some fundimental  bugs.

> We could always have a way for the output to say that BRF characters are being
> used, which would support 6-dot braille and which wouldn't have a newline
> problem.

Wouldn't the output always be brf output though if it was coming through
latex-access?

To make what I'm saying clearer you can check out the code in svn at
https://latex-access.svn.sourceforge.net/svnroot/latex-access

The testscript in the root directory should demonstrate how the latex is
converted to Braille.

For instance you could do

y = 2\sin(\frac{\pi}{2}x)+1
or
x = \frac{-b\pm\sqrt{b^2-4ac}}{2a}

To get an idea of how the translation actually works.

Dan