ppmshift(1)

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.   Unfor-
       tunately,  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)