NETPBM


THIS IS THE PRIMARY DOCUMENTATION DISTRIBUTED WITH NETPBM.  SEE THE doc
DIRECTORY IN THE SOURCE TREE FOR OTHER INFORMATION, SUCH AS INSTALLATION
INSTRUCTIONS, AND SEE <http://netpbm.sourceforge.net>.

Netpbm is a toolkit for manipulation of graphic images, including
conversion of images between a variety of different formats.  There
are over 300 separate tools in the package including converters for
about 100 graphics formats.  Examples of the sort of image
manipulation we're talking about are: Shrinking an image by 10%;
Cutting the top half off of an image; Making a mirror image; Creating
a sequence of images that fade from one image to another;

For more information on what the package does, see
<http://netpbm.sourceforge.net/doc>.

The package is intended to be portable to many platforms. It has, at
least at one time, been tested under various Unix-based systems,
Windows, Mac OS X, VMS and Amiga OS.  The maintainer uses and builds
it on a platform that consists (in relevant part) mainly of GNU
software (you probably know this kind of system by the name "Linux").

The goal of Netpbm is to be a single source for all the primitive
graphics utilities, especially converters, one might need.  So if you
know of some freely redistributable software in this vein which is not
in the package yet, you should bring it to the attention of the Netpbm
maintainer so it can be included in the next release.

Netpbm does not contain interactive tools and doesn't have a graphical
interface.

Netpbm replaces the widely spread Pbmplus package (last released
December 10, 1991).  A lot of improvements and additions have been
made.  After the latest release of Pbmplus, a lot of additional
filters began circulating on the net, which was a fairly novel state
of affairs at the time.  The aim of Netpbm was to collect these and to
turn them into a package, hence the name "Netpbm."  This work has been
performed by programmers all over the world.  If _you_ have some code
to add, please contact the Netpbm maintainer.


USING NETPBM IN A WEBSITE
-------------------------

Many people use Netpbm to perform graphics functions in a web site.  They
have CGI scripts that invoke Netpbm programs to process images for display
on a web page.  Gallery and 4Images are two web site software packages
that rely on Netpbm for graphics manipulation.

Installing Netpbm requires different skills and system access than 
installing most other web site software.  You must be able to compile
C code for the web server machine and have a basic understanding of 
how files are organized and programs run on the web server.  Diagnosing
inevitable problems usually requires shell access to the web server.

Netpbm is basic graphics software that ought to be supplied by any
web hosting service.  If it isn't on your web server already, you should
request that the system administrator add it.

The Gallery project provides an easy install package for the parts of
Netpbm that Gallery needs, and provides technical support at:

    http://gallery.sourceforge.net/forums.php


DISTRIBUTION
------------

You'll find the latest release of Netpbm source code at
<http://prdownloads.sourceforge.net/netpbm/>.

The user manual is not in the source code package.  It is available online
at <http://netpbm.sourceforge.net/doc> and you can download it from there.
See the file doc/USERDOC for details.

A list of prebuilt Netpbm distributions is on the Netpbm
website, <http://netpbm.sourceforge.net>.


PREREQUISITES
-------------

If you have trouble getting, building, or installing the
prerequisites, the Netpbm maintainer wants to know.  Since he uses
them himself, he can help you.  And if there is a problem with a
prerequisite package that its own maintainer cannot fix, it may be
possible to ship a fix with Netpbm.

To build and install Netpbm, you need GNU Make and a Perl interpreter.
You can get GNU Make from <http://www.gnu.org/software> and Perl from 
<http://www.cpan.org>.  It's possible to get around the Perl requirement
by running some of the steps on a different machine that has Perl and
doing others manually.  There is no practical substitute for GNU Make.

The Netpbm package as a whole uses over half a dozen external
libraries, but you don't necessarily need to install them all in order
to build Netpbm.  Each library is used by a few Netpbm programs, and
if you don't have the library, the Netpbm build will automatically
skip building those parts.  See
<http://netpbm.sourceforge.net/prereq.html>.

Pstopnm (the Postscript to PNM image converter) requires Ghostscript
(installed with the name 'gs' in your command search path).  And it 
requires in particular that Ghostscript be built with the relevant 
PNM device drivers.  See <http://www.ghostscript.com/doc/GPL/>.

You generally need a compiler other than Gcc 2.96.  Gcc 2.96 has a bug
in its inlining optimization.  It generates incorrect code.  Netpbm
source code takes advantage of inlining and you normally build Netpbm
with inlining enabled.  Therefore, if you use Gcc 2.96 you will get
broken Netpbm programs.  The usual symptom is bogus syntax error
messages when you run the program.  You can avoid this compiler bug by
using a -O0 compile option instead of the usual -O3.  The automatic
configuration program will usually detect that you need this and set
it up for you.  This will make some programs noticeably slower,
though.

Netpbm requires about 6 MiB of disk space, not including documentation.
The documentation is 2 MiB, but you don't necessarily have to install
it; you can just access the public copy.


INSTALLATION
------------

See doc/INSTALL.


SUPPORT
-------

The maintainer of Netpbm, since September 1999, is Bryan Henderson:

  bryanh@giraffe-data.com.  

Bryan actively maintains the package and wants to know about any bugs
or problems people have with Netpbm or suggestions for improvement.

There is no bug reporting database or mailing list.  These would not
be very useful with Netpbm because Bryan personally responds to all
bug reports and requests for help immediately.  All known bugs in the
"latest" release are listed in its release notes on Sourceforge
(updated as the bugs are reported) and the "stable" release is
generally maintained so as not to have known bugs for more than a few
days.  The doc/HISTORY file in the package may be useful if you want
to find out whether upgrading to the current release would solve your
problem.  The information in that file, on a per-release basis, is 
also in the change histories on Sourceforge.



MORE INFORMATION, DOCUMENTATION
-------------------------------

For more information about Netpbm, see <http://netpbm.sourceforge.net/doc>.

The 'doc' directory in the source tree has more information.

A good place to start for information about the wide world of computer
graphics is <http://www.faqs.org/faqs/graphics/> .