cups braille dependencies [Was: Please release the cups-filters 1.4.0-2 Debian package]

[Samuel Thibault <sthibault@debian.org>]

Giving some background for people who haven't had the whole story.

I've recently played with embossers, and written drivers for CUPS, so
that they can be used in a very standard way just like any printer.  It
happens that they already got integrated to cups-filters, and already
got uploaded to Debian.  The drivers are split in two parts:

- device-dependent drivers, which are basically simple shell scripts or
C files, which don't depend on anything beyond bash and libc

- device-independent filters, which are able to convert documents to
braille.  This part can make more or less use of liblouis, imagemagick,
antiword, etc. to be able to turn documents into nice braille printing.

So the device-dependent drivers should really not pose disk size
problem, but the second part may: there is no real end here as to what
could be implemented/integrated, etc. so we somehow have to define
what is "reasonable" to install always / by default / as suggestion /
optionally, etc.

The scripts that were added to cups-filters are able to make use of
imagemagick to turn images into braille, liblouisutdml to reformat text
into braille, poppler-utils to extract text from PDF files and render it
as text, and liblouisutdml + antiword/docx2txt to reformat .doc/.docx
documents into braille.  These all add disk usage (about 10MiB, mostly
composed of the braille tables for various languages), and apparently
this is already perhaps considered too much: bug #808057 was immediately
filed:

Michael Biebl wrote:
> Since I don't use any Braille drivers, it would be great if those
> dependencies could be demoted to suggests or recommends

Personnally, I see a lot of stuff on my disk which I won't ever use
because I'll never have the hardware, which takes much more than 10MiB,
but well.

> or pulled in via other means (e.g. via a task).

Well, the task would then be task-print-server, which I guess you have
installed?

I agree that we don't want to see this size increase too much.  For
instance, I don't plan to pull the natbraille dependency by default,
even if it'd allow some nice tex to braille translation and similar,
because natbraille would pull a whole pile of java libraries.  But can't
we agree on a reasonable set of package, to at least have basic support
for printing braille by default?  Having to look for specific drivers
for such basic things is always a pain.

Samuel