Re: [Groff] groescp update

[Werner LEMBERG]

> > Please give more information on available fonts.
> 
> It's a bit baroque: [...]

Our mails have crossed each other...

> Early printers have a few selectable typefaces.  For example "EPSON
> FX" or "IBM #1" or "IBM #2".  Both are US-ASCII plus some extra
> chars (the FX charset is extended, possibly CP 437, the IBM set is
> italic if the high bit is set IIRC, or it may be a proprinter
> charset--it's not documented, unfortunately).

It is, I think.  Using google I found the complete ESC/P reference on
a Russian service host from Epson which shows all the nasty details
for all printers manufactured.

> As a complication, various national characters (£, ¤, ë, é, ø,
> etc.) are selectable too.  These /replace/ various US-ASCII
> characters (e.g. '#' -> '£' if the UK is selected) which is
> horrible--you could easily want to use both at once.

According to the documentation you can change this with escapes at any
time, so this is no problem.

> More modern (ESC/P2) printers have "proper" character set selection,
> where you can actually specify an encoding e.g. CP437, CP850,
> ISO-8859-1 etc.  However, this is a minority of printers, and no one
> encoding is supported by all printers.  CP437 is most common,
> however.  ISO-8859-1 is very rare, and UTF-8/UCS is unheard of.

Again, the documentation says something different.  See my other mail.

> IMHO, it will be tricky to support.  I only currently have 3 models
> of dot matrix printer to test with, so it will be very difficult to
> do in a general way, not just geared towards the few models I have
> access to.  Given that it seems both non-standard and rather
> complex, I think I'll pass on implementing it for now.

I now think it is easier than expected.  The only thing I don't
understand is the strange `italic character set'...

> I've set the physical paper dimensions with "res", "hor" and "vert"
> in the DESC file.

No.  None of them gives the paper dimensions.  Please see the
groff_font man page.

> But, these are not paper dimensions but the printable area?  If I
> adjust these to specify an 8i by 10i area, that should do the trick?

Use the `papersize' keyword and translate the result to proper ESC/P
command sequences.

> [Not strictly needed now, but what if the printable area is a
> function of the physical size e.g. paperlength - 1.5i and paperwidth
> - 1i?]

(Virtual) paper dimensions used in GNU troff and real paper dimensions
of the output device are not related.


    Werner