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


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


       ppmshift shift [ppmfile]


       This program is part of Netpbm(1).

       ppmshift reads a PPM image 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.

       This  is another one of those effects I intended to use for MPEG tests.
       Unfortunately, this program will not help me here - it creates too ran-
       dom patterns to be used for animations.  Still, it might give interest-
       ing results on still images.


       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
            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.


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


       Copyright (C) 1993 by Frank Neumann

netpbm documentation           16 November 1993        Ppmshift User Manual(0)

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