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Pamendian User Manual(0)                              Pamendian User Manual(0)



NAME
       pamendian - reverse endianness of a Netpbm image


SYNOPSIS
       pamendian


DESCRIPTION
       This program is part of Netpbm(1).

       All  Netpbm formats that have samples in pure binary format with multiple bytes are defined to have them in big
       endian (most significant byte first) order.  However, there exist variations on these formats, primarily devel-
       oped  before  official  multibyte Netpbm formats existed, that are identical to Netpbm formats in every respect
       except that samples are in little endian (least signficant byte first) order.

       pamendian reverses the byte order of the sample to convert between the two formats.  If the input is true  PAM,
       PGM, or PPM, the output is the little endian variation on that format, and vice versa.

       The X Window System viewer xv expects the little endian variation of PGM and PPM.

       Programs  that come with the Independent Jpeg Group's JPEG library are known to use the little endian variation
       of PGM and PPM.

       The reason some programs use this variant is that at one time during Netpbm's darkage(1),there was a version of
       Netpbm around that used it.  But it was never formally specified.

       This program takes input only on Standard Input.  Its output is always on Standard Output.

       You  should  never have to use this program with images generated by programs in the Netpbm package or programs
       that use the Netpbm libraries.  If you do, that probably means something needs to be fixed in  those  programs.
       The  Netpbm  converter  for  any  graphics format that represents numbers in little endian form should properly
       reverse the bytes to create correct Netpbm output.

       If you create a Netpbm image from a generic stream of samples, using rawtopgm or rawtoppm, use options on those
       programs to declare the endianness of your input, thus creating correct endianness in your PGM or PPM output.


SEE ALSO
       pamdepth(1), rawtopgm(1), rawtoppm(1), pnm(1)



netpbm documentation             16 March 2002        Pamendian User Manual(0)