TIFF to PostScript <>

[Wes Chalfant]

In article <1991May31.181617.16503 at towers.uucp> robert at towers.uucp (Robert Hoquim) writes:
>
>I am in need of a way to take a Postscript file and convert it to a tiff
>file for transmission over a fax modem.  The software for the fax is the
>DigiFax software by DigiBoard Inc., which should have no effect on the
>conversion software, just thought I would throw it in.  If anyone has any
>information about such a utility that can go one way or both please let me
>know.  The OS of choice is ISC, but anything in source or even DOS (vpix?)
>would sure be of help.

	Depending on what you want to buy and what you want to port,
there are a couple of alternatives.

	The GNU Ghostscript program does a very nice job of composing a
bitmap image of postscript input.  You would probably want to write
your own ghostscript "driver"; for what you want to do, that is really
quite easy.  Your driver would tell the Ghostscript kernel what
resolution to use (you would probably use either standard or "fine"
FAX modes, which are approx. 200x100 and 200x200 pixels per inch,
respectively) and what to do with the bitmap after it was composed in
memory (probably to write it out as a TIFF file).  Ghostscript is
available either directly from the Free Software Foundation or through
an archive site for GNU software (e.g. uunet).

	Depending on what the DigiFax software supports (I'm not that
familiar with it, but have talked to them a little), you could write
the bitmap out either as a "raw" TIFF image (no compression, very
easy) or as a group 3 compressed image (harder, but doable in s/w if
you're not in a big hurry).  For dealing with TIFF files in general, I
recommend that you look at the libtiff software developed by Sam
Leffler <sam at okeeffe.berkeley.edu>.  You can get this via FTP from
ucbvax.berkeley.edu (pub/tiff/*.tar.Z) or uunet.uu.net
(graphics/tiff.tar.Z); you can also get this from uunet via modem
(either as a subscriber to uunet or via their "anonymous UUCP" 900
numbers).

	For some higher end FAX applications, people use hardware
interfaces to high speed scanners and printers that do
compression/decompression on the fly; that is where Kofax comes in.
For the type of application that you describe (FAX only), such solutions
may be overkill.  If you are integrating document image processing
into your system in general, though, you might look at some of these
hardware solutions as well.

	All of the above should work with ISC UNIX very well.