man > pamendian

Pamendian User Manual(1)               General Commands Manual              Pamendian User Manual(1)

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 developed before official multibyte Netpbm formats existed, that
       are identical to Netpbm formats in every respect except that samples  are  in  little  endian
       (least significant 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  dark  age(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 rep‐
       resents 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.


OPTIONS
       There  are  no command line options defined specifically for pamendian, but it recognizes the
       options common to all programs based on libnetpbm (See  Common Options .)


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

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/pamendian.html

netpbm documentation                        16 March 2002                   Pamendian User Manual(1)