ppmshift(1)ppmshift(1)NAMEppmshift - shift lines of a portable pixmap left or right
by a random amount
SYNOPSISppmshift 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 anima
tions. 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 ALSOppm(5), pnmcut(1), pnmflip(1), ppmdim(1), pnmcat(1)AUTHOR
Copyright (C) 1993 by Frank Neumann
16 November 1993 ppmshift(1)
