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 ppm_parsecolor() library routine ⟨libppm.html#colorname⟩  or
76              one  of the Berlin-Kay color names ⟨libppm.html#berlinkay⟩ .  In
77              the latter case, all colors that are better  described  by  that
78              Berlin-Kay color name than any other are in the mask set.
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80              The  algorithm  ppmcolormask uses to determine to which colors a
81              Berlin-Kay color name applies is based on  a  Sugeno-type  fuzzy
82              inference  system  developed  by  Kenan  Kalajdzic in 2006.  The
83              fuzzy model consists of partially  linear  membership  functions
84              defined  in  the  HSV  color space.  Although more complex algo‐
85              rithms for fuzzy color matching exist, this algorithm is  inten‐
86              tionally  simplified to achieve a satisfactory speed using rela‐
87              tively compact code.
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89              This option was new in Netpbm 10.34 (June 2006).   Before  that,
90              you  must use the color argument and cannot specify a Berlin-Kay
91              color.
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SEE ALSO

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

101       This  manual  page was generated by the Netpbm tool 'makeman' from HTML
102       source.  The master documentation is at
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104              http://netpbm.sourceforge.net/doc/ppmcolormask.html
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106netpbm documentation              1 May 2006       Ppmcolormask User Manual(0)