pnmflip - perform one or more flip operations on a portable anymap
pnmflip [-leftright|-lr] [-topbottom|-tb]
[-transpose|-xy] [-rotate90|-r90|-ccw ]
[-rotate270|-r270|-cw ] [-rotate180|-r180]
Reads a portable anymap as input. Performs one or more flip operations, in the
order specified, and writes out a portable anymap.
The flip operations available are: left for right (-leftright or
-lr); top for bottom (-topbottom or -tb); and
transposition (-transpose or -xy). In addition, some canned
concatenations are available: -rotate90 or -ccw is equivalent to
-transpose -topbottom; -rotate270 or -cw is
equivalent to -transpose -leftright; and -rotate180 is
equivalent to -leftright -topbottom.
All flags can be abbreviated to their shortest unique prefix.
Copyright (C) 1989 by Jef Poskanzer.