1\ 2.\" This man page was generated by the Netpbm tool 'makeman' from HTML source. 3.\" Do not hand-hack it! If you have bug fixes or improvements, please find 4.\" the corresponding HTML page on the Netpbm website, generate a patch 5.\" against that, and send it to the Netpbm maintainer. 6.TH "Pamendian User Manual" 0 "16 March 2002" "netpbm documentation" 7 8.SH NAME 9 10pamendian - reverse endianness of a Netpbm image 11 12.UN synopsis 13.SH SYNOPSIS 14 15\fBpamendian\fP 16 17.UN description 18.SH DESCRIPTION 19.PP 20This program is part of 21.BR "Netpbm" (1)\c 22\&. 23.PP 24All Netpbm formats that have samples in pure binary format with multiple 25bytes are defined to have them in big endian (most significant byte first) 26order. However, there exist variations on these formats, primarily developed 27before official multibyte Netpbm formats existed, that are identical to 28Netpbm formats in every respect except that samples are in little endian 29(least significant byte first) order. 30.PP 31\fBpamendian\fP reverses the byte order of the sample to convert 32between the two formats. If the input is true PAM, PGM, or PPM, the 33output is the little endian variation on that format, and vice versa. 34.PP 35The X Window System viewer \fBxv\fP expects the little endian variation 36of PGM and PPM. 37.PP 38Programs that come with the Independent Jpeg Group's JPEG library 39are known to use the little endian variation of PGM and PPM. 40.PP 41The reason some programs use this variant is that at one time 42during Netpbm's 43.BR "dark age" (1)\c 44\&, there 45was a version of Netpbm around that used it. But it was never 46formally specified. 47.PP 48This program takes input only on Standard Input. Its output is 49always on Standard Output. 50.PP 51You should never have to use this program with images generated by 52programs in the Netpbm package or programs that use the Netpbm 53libraries. If you do, that probably means something needs to be fixed 54in those programs. The Netpbm converter for any graphics format that 55represents numbers in little endian form should properly reverse the 56bytes to create correct Netpbm output. 57.PP 58If you create a Netpbm image from a generic stream of samples, 59using \fBrawtopgm\fP or \fBrawtoppm\fP, use options on those 60programs to declare the endianness of your input, thus creating 61correct endianness in your PGM or PPM output. 62 63.UN seealso 64.SH SEE ALSO 65.BR "pamdepth" (1)\c 66\&, 67.BR "rawtopgm" (1)\c 68\&, 69.BR "rawtoppm" (1)\c 70\&, 71.BR "pnm" (5)\c 72\& 73.SH DOCUMENT SOURCE 74This manual page was generated by the Netpbm tool 'makeman' from HTML 75source. The master documentation is at 76.IP 77.B http://netpbm.sourceforge.net/doc/pamendian.html 78.PP