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 ), 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

netpbm documentation                            02 February 2018                         Pamtopnm User Manual(1)