1Ppmdither User Manual(0)                              Ppmdither User Manual(0)
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NAME

6       ppmdither - ordered dither for color images
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SYNOPSIS

10       ppmdither
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12       [-dim=power]
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14       [-red=n]
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16       [-green=n]
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18       [-blue=n]
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20       [netpbmfile]
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22       All  options  can  be abbreviated to their shortest unique prefix.  You
23       may use two hyphens instead of one to designate an option.  You may use
24       either  white  space  or  an equals sign between an option name and its
25       value.
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DESCRIPTION

30       This program is part of Netpbm(1).
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32       ppmdither reads a Netpbm image as input, and applies dithering to it to
33       reduce the number of colors used down to the specified number of shades
34       for each primary.  It produces a PPM image as output.
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36       The default number of shades is 5 red, 9 green, and 5 blue, for a total
37       of  225  colors.   To convert the image to a binary rgb format suitable
38       for primitive color printers, use -red=2 -green=2 -blue=2.
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40       You can do another kind of dither -- Floyd-Steinberg --  with  pnmquant
41       or pnmremap.
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OPTIONS

45       -dim power
46               The  size  of  the dithering matrix.  The dithering matrix is a
47              square whose dimension is a power of 2.  power is that power  of
48              2.  The default is 4, for a 16 by 16 matrix.
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51       -red=n The number of red shades to be used, including black; minimum of
52              2.
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54              Default is 5.
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57       -green n
58              The number of green shades to be used, including black;  minimum
59              of 2.
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61              Default is 9.
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64       -blue n
65              The  number  of blue shades to be used, including black; minimum
66              of 2.
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68              Default is 5.
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SEE ALSO

73       pamditherbw(1), pamdepth(1), pnmquant(1), pnmremap(1), ppm(1)
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AUTHOR

77       Copyright (C) 1991 by Christos Zoulas.
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81netpbm documentation           16 December 2009       Ppmdither User Manual(0)