Re: Print eight-bit-* characters with ps-print

[Kenichi Handa <handa@etl.go.jp>]

"Eli Zaretskii" <eliz@is.elta.co.il> writes:
> I use ps-print a lot, and it annoys me that it whines about
> eight-bit-control and eight-bit-graphic characters not having fonts to
> print them with.  (These charsets are Emacs's invention, so there's no
> chance anyone will ever have a font for them.)

> So I came up with the change below.  It doesn't really print the same
> glyphs you see on your screen--that's impossible without knowing what
> fonts are available to your printer or PostScript interpreter.  But at
> least the whining is gone, and for many cases, such as those \222
> characters and Latin-1 email messages sent as ``charset=US-ASCII'', it
> does DTRT.

We already have a function ps-control-character that
properly print control codes, eight-bit-control, and
eight-bit-graphic.

So, to just stop whining about eight-bit-*, what we need is
to delete eight-bit-control and eight-bit-graphic from
charsets in this code (in ps-mule-begin-job of ps-mule.el):

       ;; Initialize `ps-mule-charset-list'.  If some characters aren't
       ;; printable, warn it.
       (let ((charsets (find-charset-region from to)))
	 (setq charsets (delq 'ascii (delq 'unknown (delq nil charsets)))
	       ps-mule-charset-list charsets)

Please try to add more delq for eight-bit-* here, and set
ps-print-control-characters to `8-bit' (the default is
`8-bit-control').  Then all eight-bit-* should be printed in
octal form.  Isn't it what you want?

> (Btw, it looks like iso-safe can safely encode eight-bit-* characters.
> If that's true, I think we should update its doc string.  Handa-san,
> can you please comment on this?)

This is a difficult part.  Currently, as far as I remember
all coding-systems encode them as is.  They are treated as
special bytes that should be written out as is.  I'm not
sure whether or not we should make iso-safe as an exception.
Instead, how about documenting clearly that there's a super
rule that any coding system encodes eight-bit-* as is?

---
Ken'ichi HANDA
handa@etl.go.jp