NAME

       ppmshift - shift lines of a portable pixmap left or right by a random amount

SYNOPSIS

       ppmshift shift [ppmfile]

DESCRIPTION

       Reads a portable pixmap as input. Shifts every row of image data to the left or right by a
       certain amount. The 'shift' parameter determines by how many pixels a row is to be shifted
       at most.

       Another  one  of  those  effects  I  intended  to use for MPEG tests.  Unfortunately, this
       program will not help me here - it creates too random patterns to be used for  animations.
       Still, it might give interesting results on still images.

EXAMPLE

       Check   this   out:   Save   your   favourite   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
         pnmcut 0 0 800 300 cs.ppm >upper.ppm

         # take the lower half, flip it upside down, dim it and distort it a little
         pnmcut 0 300 800 300 cs.ppm | pnmflip -tb | ppmdim 0.7 |
            ppmshift 10 >lower.ppm

         # and concatenate the two pieces
         pnmcat -tb 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(5), pnmcut(1), pnmflip(1), ppmdim(1), pnmcat(1)

AUTHOR

       Copyright (C) 1993 by Frank Neumann

                                         16 November 1993                             ppmshift(1)