[gs-devel] Ghostscript Driver for a Braille Printer

[Ralph Giles]

On Tue, Nov 23, 2004 at 10:32:54PM +0000, Matthew T. Atkinson wrote:

> I've been on this list for a while but have not posted yet.  I am a 4th
> year Computer Science student at Loughborough University in the UK.  My
> final year project is concerned with making lecture notes accessible to
> blind students in the department.  Part of this work involves writing a
> driver for the Braille embosser we have (a ``Tiger Advantage'', created
> by ViewPlus Technologies) that will run on UNIX-like OSes.

Cool!

> Firstly, I would like to know if this is the type of thing you'd be
> willing to include in the mainstream (GPL) Ghostscript distribution. 
> We're hoping that this is the case, so that we can ensure that all
> lecturers will easily be able to print their notes to the Braille
> printer (as GPL Ghostscript is included in most distributions of
> UNIX/Linux).

In theory yes. We are trying to keep the number of device drivers
to a minimum, but we're also interested in supporting accessibility
and the academic market, and this sounds like something not covered
by the normal driver suites.

> The back-end would be similar to many others.  It is primarily going to
> be used for printing input generated from LaTeX documents that have been
> processed to use a braille font.  Later on, I hope to experiment with
> other formats such as converting LaTeX to XML (in an effort to make the
> maths more accessible).

Ok, if you're using a braille font then you can use raster output, and
don't need high-level access to the text being printed? If so, you have
more options.

> One potential issue I can see you as Ghostscript developers having with
> this project is that the core driver for the printer is, alas, binary
> only.  I am hoping to create a GPL wrapper (and stub library, perhaps)
> that could be included in Ghostscript but would only function fully if
> the core library was replaced by the one that can be downloaded (which
> I'm in the process of porting to PPC from x86).

Ah, this is too bad. Have you considered writing your wrapper as an
ijs server? Then it could be distributed separately from Ghostscript,
use other rips, etc. This only works if you can accept raster data,
though.

Note that any distribution of GPL Ghostscript bundled with non-GPL
code runs counter to the Artifex GPL iterpretation. Artifex might
well grant you an exemption, but it's something you need to worry
about while you're tied to someone else's non-free driver.

> I think I've gone on for long enough.  I hope that I'll be able to
> contribute to Ghostscript -- it would make a huge difference to all of
> the students who currently can't access LaTeX-based lecture notes.

Sure. Sounds like an interesting project!

 -r