netpbm - version 1mar1994
                           N E T P B M

Netpbm is a toolkit for conversion of images between a variety of
different formats, as well as to allow a few basic image operations.

Netpbm is based on the widely spread Pbmplus package (release: 10 Dec 91).
On top of that, a lot of improvements and additions have been made. After
the latest release of Pbmplus, a lot of additional filters have been
circulating on the net. The aim of Netpbm was, to collect these and to turn
them into a package. This work has been performed by a group of program-
mers all over the world.

Below this line follows the original README file from Pbmplus.

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                  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.