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
       proportional 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 actual 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 different from what pamditherbw does because of
       differences in internal calculation.

       If you just want to convert a PGM image with maxval 1 to PBM, use pamtopnm(1).

SEE ALSO

       pamditherbw(1), pamtopnm(1), pbmtopgm(1), pamthreshold(1), pbmreduce(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)