NAME

       ppmshift - shift lines of a PPM image left or right by a random amount

SYNOPSIS

       ppmshift shift [ppmfile]

DESCRIPTION

       This program is part of Netpbm(1).

       ppmshift  reads  a  PPM  image as input.  It shifts every row of image data to the left or
       right by a random amount, within a range of shift  pixels.   The  random  distribution  is
       uniform, centered at zero movement.

       The  randomness  in the image is limited before Netpbm 10.37 (December 2006) -- if you run
       the program twice in the same second, you may get identical output.

       This is an effect the author intended to use for MPEG tests.  Unfortunately, this  program
       is not useful for that - it creates too random patterns to be used for animations.  Still,
       it might give interesting results on still images.

OPTIONS

       There are no command line options defined specifically for ppmshift, but it recognizes the
       options common to all programs based on libnetpbm (See
        Common Options ⟨index.html#commonoptions⟩ .)

EXAMPLE

       Check   this   out:   Save   your   favorite   model's   picture   from   something   like
       alt.binaries.pictures.supermodels (ok, or from any other picture source),  convert  it  to
       ppm, and process it e.g. like this, assuming the picture is 800x600 pixels:

            #take the upper half, and leave it like it is
            pamcut -top=0 -width=800 -height=300 cs.ppm >upper.ppm

            #take the lower half, flip it upside down, dim it and distort it a little
            pamcut -top=300 -width=800 -height=300 cs.ppm | \
                pamflip -topbottom | \
                ppmdim 0.7 | \
                ppmshift 10 >lower.ppm

            #and concatenate the two pieces
            pnmcat -topbottom upper.ppm lower.ppm >newpic.ppm

       The  resulting picture looks like the image being reflected on a water surface with slight
       ripples.

SEE ALSO

       ppm(1), pamcut(1), pamflip(1), ppmdim(1), pnmcat(1)

AUTHOR

       Copyright (C) 1993 by Frank Neumann

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/ppmshift.html