1Ppmshift User Manual(0)                                Ppmshift User Manual(0)
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NAME

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

10       ppmshift shift [ppmfile]
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DESCRIPTION

14       This program is part of Netpbm(1).
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16       ppmshift reads a PPM image as input.  It shifts every row of image data
17       to the left or right by a random amount, within a range of  shift  pix‐
18       els.  The random distribution is uniform, centered at zero movement.
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20       The  randomness  in  the image is limited before Netpbm 10.37 (December
21       2006) -- if you run the program twice in the same second, you  may  get
22       identical output.
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24       This  is an effect the author intended to use for MPEG tests.  Unfortu‐
25       nately, this program is not useful for that -  it  creates  too  random
26       patterns  to  be used for animations.  Still, it might give interesting
27       results on still images.
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OPTIONS

31       There are no command line options defined  specifically  for  ppmshift,
32       but it recognizes the options common to all programs based on libnetpbm
33       (See
34        Common Options ⟨index.html#commonoptions⟩ .)
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EXAMPLE

38       Check this out: Save your favorite model's picture from something  like
39       alt.binaries.pictures.supermodels   (ok,  or  from  any  other  picture
40       source), convert it to ppm, and process it e.g. like this, assuming the
41       picture is 800x600 pixels:
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43            #take the upper half, and leave it like it is
44            pamcut -top=0 -width=800 -height=300 cs.ppm >upper.ppm
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46            #take the lower half, flip it upside down, dim it and distort it a little
47            pamcut -top=300 -width=800 -height=300 cs.ppm | \
48                pamflip -topbottom | \
49                ppmdim 0.7 | \
50                ppmshift 10 >lower.ppm
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52            #and concatenate the two pieces
53            pnmcat -topbottom upper.ppm lower.ppm >newpic.ppm
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56       The  resulting  picture looks like the image being reflected on a water
57       surface with slight ripples.
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SEE ALSO

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

66       Copyright (C) 1993 by Frank Neumann
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DOCUMENT SOURCE

69       This manual page was generated by the Netpbm tool 'makeman'  from  HTML
70       source.  The master documentation is at
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72              http://netpbm.sourceforge.net/doc/ppmshift.html
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74netpbm documentation           20 November 2008        Ppmshift User Manual(0)
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