pnm - Netpbm superformat
The PNM format is just an abstraction of the PBM, PGM, and PPM formats. I.e. the
name "PNM" refers collectively to PBM, PGM, and PPM.
The name "PNM" is an acronym derived from "Portable Any
Map." This derivation makes more sense if you consider it in the context
of the other Netpbm format names: PBM, PGM, and PPM.
The more general term "Netpbm format" refers to the PNM formats plus
PAM.
PNM is principally used with
Netpbm(1).
Note that besides being names of formats, PBM, PGM, PPM, and PNM are also
classes of programs. A PNM program can take PBM, PGM, or PPM input. That's
nothing special -- a PPM program can too. But a PNM program can often produce
multiple output formats as well, and a PNM program can see the difference
between PBM, PGM, and PPM input and respond to each differently whereas a PPM
program sees everything as if it were PPM. This is discussed more in
the description of the netpbm programs" (1).
"pnm" also appears in the names of the most general
Netpbm library
routines(1), some of which aren't even related to the PNM format.
No Internet Media Type (aka MIME type, content type) for PNM has been registered
with the IANA, but the value image/x-portable-anymap is conventional.
Note that there are also conventional Internet Media Types for each of the PNM
subformats. The recommended practice is to use those in preference to the PNM
code when it is convenient to do so.
There are no requirements on the name of a PNM file, but the convention is to
use the suffix "pbm", "pgm", or "ppm", depending
on the particular subformat, or "pnm" if it is not convenient to
distinguish the subformats.
ppm(1),
pgm(1),
pbm(1),
pam(1),
programs that
process PNM(1),
libnetpbm(1)
This manual page was generated by the Netpbm tool 'makeman' from HTML source.
The master documentation is at
- http://netpbm.sourceforge.net/doc/pnm.html