1Ppmcolormask User Manual(0)                        Ppmcolormask User Manual(0)
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NAME

6       ppmcolormask - produce mask of areas of a certain color in a PPM file
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SYNOPSIS

10       ppmcolormask -color=color_list [ppmfile]
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12       ppmcolormask color [ppmfile]
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EXAMPLES

16           ppmcolormask -color red testimg.ppm >redmask.pbm
17           pamcomp background.ppm testimg.ppm -alpha=redmask.pbm >test.ppm
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19           ppmcolormask -color=red,pink,salmon testimg.ppm >reddishmask.pbm
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21           ppmcolormask -color=bk:red,bk:orange,bk:yellow testimg.ppm >firemask.pbm
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DESCRIPTION

26       This program is part of Netpbm(1).
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28       ppmcolormask reads a PPM file as input and produces a PBM (bitmap) file
29       as output.  The output file is the same dimensions as  the  input  file
30       and is black in all places where the input file is a color indicated by
31       the -color option, and white everywhere else.
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33       The output of ppmcolormask is useful as a transparency  mask  input  to
34       pamcomp.   Note that you don't need ppmcolormask and pamcomp if you are
35       ultimately converting to PNG with  pnmtopng  because  the  -transparent
36       option on pnmtopng does the same thing.
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38       ppmfile  is the input file.  If you don't specify ppmfile, the input is
39       from Standard Input.
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41       The output goes to Standard Output.
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43       In the obsolete alternative syntax, specifying the color names a single
44       exact color to be masked.
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46       ppmchange does a similar thing: it modifies an image by changing colors
47       you specify to other colors you specify.  The  two  programs  give  you
48       somewhat different means of specifying colors in the input image.
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50       To make a mask of an image's background, without having to tell it what
51       color it is, use pambackground.
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OPTIONS

55       -color=color_list
56              This mandatory option specifies the colors that are to be masked
57              (where the image is one of these colors, the output mask will be
58              black).
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60              Examples:
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64       ·      -color=red
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66       ·      -color=red,pink,salmon
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68       ·      -color=rgb:80/80/ff
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70       ·      -color=bk:red,bk:orange,bk:yellow
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73              color_list is a list of colors separated by commas.  Each  color
74              is  either  an exact color name as described for the argument of
75              the          pnm_parsecolor()          library           routine
76              ⟨libnetpbm_image.html#colorname⟩  or one of the Berlin-Kay color
77              names ⟨libppm.html#berlinkay⟩ .  In the latter case, all  colors
78              that are better described by that Berlin-Kay color name than any
79              other are in the mask set.
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81              The algorithm ppmcolormask uses to determine to which  colors  a
82              Berlin-Kay  color  name  applies is based on a Sugeno-type fuzzy
83              inference system developed by  Kenan  Kalajdzic  in  2006.   The
84              fuzzy  model  consists  of partially linear membership functions
85              defined in the HSV color space.   Although  more  complex  algo‐
86              rithms  for fuzzy color matching exist, this algorithm is inten‐
87              tionally simplified to achieve a satisfactory speed using  rela‐
88              tively compact code.
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90              This  option  was new in Netpbm 10.34 (June 2006).  Before that,
91              you must use the color argument and cannot specify a  Berlin-Kay
92              color.
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SEE ALSO

98       pamfind(1),  pambackground(1),  ppmchange(1),  pgmtoppm(1), pamcomp(1),
99       pbmmask(1), pnmtopng(1), ppm(1)
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DOCUMENT SOURCE

102       This manual page was generated by the Netpbm tool 'makeman'  from  HTML
103       source.  The master documentation is at
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105              http://netpbm.sourceforge.net/doc/ppmcolormask.html
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107netpbm documentation              1 May 2006       Ppmcolormask User Manual(0)