Pamendian User Manual(0) Pamendian User Manual(0)NAMEpamendian - reverse endianness of a Netpbm image
SYNOPSISpamendianDESCRIPTION
This program is part of Netpbm(1)
All Netpbm formats that have samples in pure binary format with multi‐
ple bytes are defined to have them in big endian (most significant byte
first) order. However, there exist variations on these formats, pri‐
marily 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 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 pro‐
grams 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 cre‐
ate 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 ALSOpamdepth(1) , rawtopgm(1) , rawtoppm(1) , pnm(1)netpbm documentation 16 March 2002 Pamendian User Manual(0)
