Very Computer

(Cross-posted to comp.os.linux.misc to make sure enough Linux users see
it. - if you reply, please follow up only to comp.lang.postscript, or
wherever the Ghostscript discussion should be.)

I am running Linux, and am interested in arranging a generic printer
driver library, along similar lines to that provided by MS-Windows - the
calling program needs to know nothing about the printer involved, just the
paper size and resolution. Drivers for individual printers are to be in
separate executables (or dlls).

 I put together some plans for this over the vacation, although they're
now out of date. They're on the Web site listed below, though, because I
couldn't stand to just delete them.

 When I got back to College, I did some more research into the printing
mechanisms already available. What I found was this:

Extract from ghostscript-4.02/new-user.txt:

Quote:> ********
> ******** An overview of Ghostscript ********
> ********

> Ghostscript is the name of a set of software that provides:

>         - An interpreter for the PostScript (TM) language and the Adobe
> Portable Document Format (PDF -- sometimes confused with Acrobat, Adobe's
> PDF browser/editor product), and

>         - A set of C procedures (the Ghostscript library) that implement
> the graphics and filtering (data compression / decompression / conversion)
> capabilities that appear as primitive operations in the PostScript language
> and in PDF.

__Please__ could we have Ghostscript modified so that it's possible to
separate these two functions, leaving the graphics library as a
dynamically linked executable which can then be used by any program?

It would also be useful if the individual drivers didn't have to be
compiled in to the library. Couldn't they also be dynamically linked? So
all you have to do to use a new driver is build a small dll, and add it to
a configuration file. A lot simpler than fetching and compiling the whole
GS source tree. Especially if you have a slow machine, a small hard drive
and/or a slow connection.

Linux needs this kind of support library in order to encourage more
porting of commercial applications. Given that Ghostscript is already
doing almost what we want, _PLEASE_ can we have it separated to make it
usable by other applications.

Support for text modes of the printers also needs adding, so that printing
something like man pages can use the printer fonts and attributes like
(bold, italics, etc.) without resorting to printing graphics, which is
horribly slow in comparison. But let's get the basics available first,
shall we?

     ----      ------------------------------------------------      ----

        Robinson College,            WWW: http://dwmw2.robinson.cam.ac.uk

          CB3 9AN,                  Room: C9
           England.                  Tel: +44 (0) 976 658355
     ----      ------------------------------------------------      ----

Quote:>Ghostscript appears to contain exactly the functionality that we require,
>quite distinct from the interpreter. The only problem is that it's
>statically linked to the the interpreter.

If you are comparing with the printer drivers used in Windows and
Macintosh, this is very different. They interpret the same range of
calls used to paint on the screen (fill circle, write text, draw
line...) as well as bitmap calls.

You need more than bitmap printing support for most applications. For
instance, how are you to print text? This is also an inefficient way
to print simple pages.

It seems to me you might as well treat GhostScript as the universal
printer driver. Almost all UNIX applications already produce
PostScript, of greater or lesser quality.

If you want to complete with the Windows/Mac portable driver concept,
which in my opinion is a key part of what sets these systems apart
from UNIX in consumer terms. you have an uphill struggle.
----------------------------------------

Visit http://www.veryComputer.com/,
PSAlter, psalters, tea, and small * animals. And stuff.  

: (Cross-posted to comp.os.linux.misc to make sure enough Linux users see
: it. - if you reply, please follow up only to comp.lang.postscript, or
: wherever the Ghostscript discussion should be.)

: I am running Linux, and am interested in arranging a generic printer
: driver library, along similar lines to that provided by MS-Windows - the
: calling program needs to know nothing about the printer involved, just the
: paper size and resolution. Drivers for individual printers are to be in
: separate executables (or dlls).

I utterly fail to see why this is needed.  Ghostscript just needs to be
hooked into your lpr setup and it is already a very nice universal printer
driver.  Just open a pipe to lpr and feed out postscript.  Postscript
is a perfectly good printing API; in fact, it is probably the best
one in existance.  Why do a Microsoft and invent a new one ?

--randy

    RC> Why do a Microsoft and invent a new one ?

That's a good one - thank you for that!

Next time we'll use Netscape (-> its superfluous HTML extensions) instead.

    RC> --randy