Pgmtopbm User Manual(1) General Commands Manual Pgmtopbm User Manual(1)
NAME
pgmtopbm - convert a PGM image to PBM
SYNOPSIS
pgmtopbm
[-floyd | -fs | -threshold | -hilbert | -dither8 | -d8 | -cluster3 |
-c3 | -cluster4 | -c4 | -cluster8 | -c8]
[-value val]
[-clump size]
[-randomseed integer]
[pgmfile]
DESCRIPTION
This program is part of Netpbm(1).
This program is almost entirely obsolete since Netpbm 10.23 (July
2004). Use pamditherbw(1) to do what this program used to do.
pgmtopbm never was the simple converter it appeared to be. It was a
dithering program. Unfortunately, it didn't do the dithering properly
because it treated the PGM input samples as if they were directly pro-
portional to light intensity, but they are actually gamma-adjusted.
pamditherbw is backward compatible with pgmtopbm except that it
• does the correct gamma adjustments.
• produces PAM output instead of PBM. (Modern Netpbm programs
that accept PBM input also accept PAM input, but if you need ac-
tual PBM, you can use pamtopnm with pamditherbw).
So use the manual for pamditherbw for pgmtopbm, except ignore
anything that says it was added after Netpbm Release 10.23 and
ignore any options that are not shown in the synopsis above.
Although pgmtopbm is mostly obsolete, the simple threshold method
(specified by -threshold) is an exception. Unlike the other conversion
methods, gamma-adjustment is not an issue with simple thresholding and
pgmtopbm can produce PBM output directly. Note that even in this basic
mode of operation pgmtopbm may produce output which is slightly differ-
ent from what pamditherbw does because of differences in internal cal-
culation.
If you just want to convert a PGM image with maxval 1 to PBM, use pam-
topnm(1).
SEE ALSO
pamditherbw(1), pamtopnm(1), pbmtopgm(1), pamthreshold(1), pbmre-
duce(1), pgm(1), pbm(1)
AUTHOR
Copyright (C) 1989 by Jef Poskanzer.
DOCUMENT SOURCE
This manual page was generated by the Netpbm tool 'makeman' from HTML
source. The master documentation is at
http://netpbm.sourceforge.net/doc/pgmtopbm.html
netpbm documentation 17 July 2020 Pgmtopbm User Manual(1)
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