ppmshift(1) - phpMan

Ppmshift User Manual(0)                                                   Ppmshift User Manual(0)



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 uni-
       form, 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.


EXAMPLE
       Check this out: Save your favorite model's picture from something  like  alt.binaries.pic-
       tures.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

netpbm documentation                     20 November 2008                 Ppmshift User Manual(0)

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