[ This is the original README from the Unix PBMPlus.  I only deleted the ]
[ Installation and Contents parts.  See the amiga.readme file for more   ]
[ information, especially on the Support and Copyrights parts.      Ingo ]

                  Extended Portable Bitmap Toolkit
                      Distribution of 10dec91
                   Previous distribution 30oct91


PBMPLUS is a toolkit for converting various image formats to and from
portable formats, and therefore to and from each other.  The idea is,
if you want to convert among N image formats, you only need 2*N
conversion filters, instead of the N^2 you would need if you wrote each
one separately.

In addition to the converters, the package includes some simple tools
for manipulating the portable formats.

The package is broken up into four parts.  First is PBM, for bitmaps (1
bit per pixel).  Then there is PGM, for grayscale images.  Next is PPM,
for full-color images.  Last, there is PNM, which does content-independent
manipulations on any of the three internal formats, and also handles
external formats that have multiple types.

The parts are upwards compatible: PGM reads both PGM and PBM files and
writes PGM; PPM reads all three and writes PPM; and PNM reads all three
and writes, usually, the same type as it read.  Whenever PNM makes an
exception and "promotes" a file to a higher format, it lets you know.


SUPPORT

I've tested this stuff under SysV and BSD, on Sun 3's 4's and 386's and
Sequents and Vaxen and HPs, with cc and gcc.  Nevertheless, I'm sure bugs
remain, and portability to systems like Amigas and IBM compatibles is
an interesting question.  Feedback is welcome; send bug reports,
enhancements, etc. to this address:

    jef@well.sf.ca.us
    apple!well!jef

When sending bug reports, always include the output from running any
PBMPLUS program with the -version flag.  Also include the type of
system you are on, what compiler you used, and whether you are using
Makefiles or Imakefiles.  I try to respond to bug reports and enhancements
promptly; say, within a week.

Also, if there is a new format or feature you would like to have added
to the package, feel free to drop me a line.  If it's a format, include
whatever documentation you have, and if possible a uuencoded sample.
My response time will depend on how busy I am, and how easy the job
looks.  If you need it right away, or it's a complicated job, you might
consider paying me; lately, that's how a lot of work on the package has
gotten done.

Finally, if you have access to Usenet, there's a newsgroup called
alt.graphics.pixutils which is specifically for discussion of image
conversion and editing packages such as PBMPLUS.  Posting stuff there
is even better than mailing it to me, since it lets other people help
out with the answers.


HOW TO FIND THE RIGHT CONVERTER

Some people get confused by all the different names.  If you want to
convert a pbm file to a Sun raster file, is it pbmtorast, pgmtorast,
ppmtorast, or pnmtorast?  In this case some of the confusion might be
because previous versions of the package did in fact have both
pbmtorast and ppmtorast.  But mostly it's just too many different
things to hold in your short term memory.  Fine, so don't even try to
remember what's what.  That's what computers are for.  Unix, at least
BSD Unix, has this great indexing feature on the "man" program.  You
say "man -k <keyword>" and it gives you all the one-line descriptions
with that keyword in them.  All the PBMPLUS man pages have nice useful
one-line descriptions, that mention all the relevant keywords.  Try it,
you'll like it.


COPYRIGHTS

All the software in this package, whether by me or by a contributer,
has a copyright similar to this one:

    Permission to use, copy, modify, and distribute this software and its
    documentation for any purpose and without fee is hereby granted, provided
    that the above copyright notice appear in all copies and that both that
    copyright notice and this permission notice appear in supporting
    documentation.  This software is provided "as is" without express or
    implied warranty.

Many people get confused by this legalese, especially the part about
"without fee".  Does this mean you can't charge for any product that
uses PBMPLUS?  No.  All it means is that you don't have to pay me.
You can do what you want with this software.  Build it into your
package, steal code from it, whatever.  Just be sure to let people
know where it came from.

[ Remember that this copyright only applies to the PBMPlus SOURCES, not  ]
[ the Amiga binaries from my port.  In fact, there are some heavy dis-   ]
[ tribution restrictions on them.  Read the file `amiga.readme' in the   ]
[ texts archive for more information on this subject.               Ingo ]