.\"	$Header: /usr/people/sam/tiff/contrib/fax2ps/RCS/fax2ps.1,v 1.3 92/02/10 19:07:43 sam Exp $
.\"
.\" Copyright (c) 1991, 1992 by Sam Leffler.
.\" All rights reserved.
.\"
.\" This file is provided for unrestricted use provided that this
.\" legend is included on all tape media and as a part of the
.\" software program in whole or part.  Users may copy, modify or
.\" distribute this file at will.
.\"
.TH FAX2PS 1 "April 29, 1991"
.SH NAME
fax2ps \- convert a
.SM TIFF
facsimile to compressed PostScript\(tm
.SH SYNOPSIS
.B fax2ps
[
.B \-a
] [
.B \-p
.IR pagenumber
] [
.B \-s
] [
.IR file ...
]
.SH DESCRIPTION
.I Fax2ps
reads one or more
.SM TIFF
facsimile image files and prints a compressed form of
PostScript on the standard output that is suitable for printing.
Each page is scaled to fill an 8.5" by 11" page.
.PP
By default
.I fax2ps
generates PostScript for all pages in the file.
The
.B \-p
option can be used to select one or more pages from
a multi-page document.
.PP
.I Fax2ps
generates a compressed form of PostScript that is
optimized for sending pages of text to a PostScript
printer attached to a host through a low-speed link (such
as a serial line).
Each output page is filled with white and then only
the black areas are drawn.
The PostScript specification of the black drawing operations
is optimized by using a per-page dictionary of the most
common horizontal move-draw operations required to fill
the black regions on the page.
This compression scheme typically results in a substantially
reduced PostScript description, relative to the straightforward
imaging of the page with a PostScript
.I image
operator.
This algorithm can, however, be ineffective
for continuous-tone and white-on-black images.
For these images, it sometimes is more efficient to send
the raster bitmap image directly.
.PP
The compressed PostScript description uses codes made
up from an extended alphabet of 
.I "safe characters"
(i.e. those characters whose concatentation are unlikely
to be interpreted as a PostScript operator or name).
By default, this alphabet is comprised of
upper-case alphabetics as well as some other
printable characters.
To restrict the alphabet to only upper-case alphabetics, the
.B \-a
option may be used.
To force 
.I fax2ps
to include statistics about the effectiveness of the generated
code dictionary in the output PostScript file, the
.B \-s
option may be specified.
(The statistics are included as PostScript comments.)
the facsimile decoding on the standard output.
.SH DIAGNOSTICS
Some messages about malformed 
.SM TIFF
images come from the
.SM TIFF
library.
.PP
Various messages about badly formatted facsimile images
may be generated due to transmission errors in received
facsimile.
.I Fax2ps
attempts to recover from such data errors by resynchronizing
decoding at the end of the current scanline.
This can result in long horizontal black lines in the resultant
PostScript.
.SH BUGS
Should probably figure out when it is doing a poor
job of compressing the output and just generate 
PostScript to image the bitmap raster instead.
.SH "SEE ALSO"
.IR libtiff (3)