NAME

       pamtopnm - convert PAM image to PBM, PGM, or PPM

SYNOPSIS

       pamtopnm

       [-assume]

       [pnmfile]

       Minimum  unique  abbreviation of option is acceptable.  You may use double hyphens instead
       of single hyphen to denote options.  You may use white space in place of the  equals  sign
       to separate an option name from its value.

DESCRIPTION

       This program is part of Netpbm(1).

       pamtopnm reads a PAM image as input and produces an equivalent PBM, PGM, or PPM (i.e. PNM)
       image, whichever is most appropriate, as output.

       pamtopnm assumes the PAM image represents the information required for a PBM, PGM, or  PPM
       image if its tuple type is "BLACKANDWHITE", "GRAYSCALE", or "RGB" and its depth and maxval
       are appropriate.  If this is not the case, pamtopnm fails.

       However, you can override the tuple type requirement with the -assume option.

       pamtopnm produces a PPM image if the input PAM has depth 3 or 4; it produces PGM or PBM if
       the  input  PAM has depth 1 or 2.  Whether it produced PGM or PBM depends upon the maxval:
       PBM for 1, PGM for anything higher.  The tuple type does not play a  role  in  determining
       the output type.  You can use Netpbm programs such as pgmtopgm to generate a different PNM
       output, but remember that Netpbm program that expects PGM input will take PBM and so on.

       Note that it's possible for an image which is formally  color  to  in  fact  contain  only
       shades  of  gray  and  for  an image which is formally grayscale to contain only black and
       white.  This program pays no attention to that; an RGB input image produces a  PPM  output
       image even if all the pixels are gray.  But you can use ppmtopgm to convert a PPM that you
       know is grayscale to the equivalent PGM, and you can use pamthreshold  to  convert  a  PGM
       image  you know is black and white to a black and white PAM image and then use pamtopnm to
       convert that to PBM.

       As with any Netpbm program that reads PAM images, pamtopnm also reads  PNM  images  as  if
       they  were PAM.  In that case, pamtopnm's functions reduces to simply copying the input to
       the output.  But this can be useful in a program that doesn't know whether  its  input  is
       PAM or PNM but needs to feed it to a program that only recognizes PNM.

OPTIONS

       In addition to the options common to all programs based on libnetpbm (most notably -quiet,
       see
        Common Options ⟨index.html#commonoptions⟩ ), pamtopnm recognizes  the  following  command
       line option:

       -assume
              When  you specify -assume, you tell pamtopnm that you personally vouch for the fact
              that the tuples contain the same data as belongs in the channels of a PBM, PGM,  or
              PPM  file.   The  depth must still conform, though, so to truly force a conversion,
              you may have to run the input  through  pamchannel  first.   But  be  careful  with
              -assume.  When you -assume, you make an -ass of u and me.

SEE ALSO

       pbmtopgm(1),  pamditherbw(1),  pgmtoppm(1),  ppmtopgm(1), pamthreshold(1), pam(1), pnm(1),
       pbm(1), pgm(1), ppm(1)

HISTORY

       pamtopnm was new, along with the PAM format, in Netpbm 9.7 (August 2000).

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/pamtopnm.html