Provided by: netpbm_11.01.00-2build1_amd64 bug

NAME

       pnmquant - quantize the colors in a Netpbm image to a smaller set

SYNOPSIS

       pnmquant        [-center|-meancolor|-meanpixel]        [-floyd|-fs]       [-nofloyd|-nofs]
       [-spreadbrightness|-spreadluminosity] {[-norandom]|[-randomseed=n]} ncolors [pnmfile]

       All options can be abbreviated to their shortest unique prefix.  You may use  two  hyphens
       instead  of  one  to  designate an option.  You may use either white space or equals signs
       between an option name and its value.

DESCRIPTION

       This program is part of Netpbm(1).

       pnmquant reads a PNM image as input.  It chooses ncolors  colors  to  best  represent  the
       image, maps the existing colors to the new ones, and writes a PNM image as output.

       This  program is simply a combination of pnmcolormap and pnmremap, where the colors of the
       input are remapped using a color map which is generated  from  the  colors  in  that  same
       input.   The  options have the same meaning as in those programs.  See their documentation
       to understand pnmquant.

       You may actually get fewer than ncolors colors in the output because
         the method pnmcolormap uses to choose the best set of colors for the
         image is not the same as the method pnmremap uses to determine the
         best color from the set to represent an individual color.  For example,
         pnmcolormap may include salmon in the color map as the best
         representative of a pink pixel in the input and include coral in the color
         map as the best representative of an actual coral pixel in the input.  But
         pnmremap is free to use any color in the color map to represent that
         pink pixel and would find coral is a closer match for pink than salmon and
         therefore use coral for pink.  pnmremap might not use salmon
         for any pixel.

       This waste of a slot in the color map is a consequence of the approximate
         method pnmcolormap uses in order to compute the color map with a
         practical amount of computation.

   Running pnmcolormap and pnmremap Separately
       It is much faster to call pnmcolormap and pnmremap directly than  to  run  pnmquant.   You
       save  the  overhead of the Perl interpreter and creating two extra processes.  pnmquant is
       just a convenience.

       Here is an example of the relationship between the programs:

       This:

           $ pnmquant 256 myimage.pnm >/tmp/colormap.pnm >myimage256.pnm

       does essentially this:

           $ pnmcolormap 256 myimage.pnm >/tmp/colormap.pnm
           $ pnmremap -mapfile=/tmp/colormap.pnm myimage.pnm >myimage256.pnm

OPTIONS

       In addition to the options common to all programs based on libnetpbm (most notably -quiet,
       see
        Common  Options  ⟨index.html#commonoptions⟩  ), pnmquant recognizes the following command
       line options:

   Options Passed to pnmcolormap
       These options control the selection of the palette.  They are options to pnmcolormap(1).

       -center

       -meancolor

       -meanpixel

       -spreadbrightness

       -spreadluminosity

   Options Passed to pnmremap
       These options control which color from the palette the program uses to
         replace a pixel of a certain color from the input.  They are options to pnmremap(1).

       -floyd

       -fs

       -nofloyd

       -nofs

       -norandom

       -randomseed

       -norandom

HISTORY

       pnmquant did not exist before Netpbm 9.21 (January 2001).  Before that, ppmquant  did  the
       same  thing, but only on PPM images.  ppmquant continues to exist, but is only a front end
       (for name compatibility) to pnmquant.

       -version did not exist before Netpbm 10.75 (June 2016).

       -norandom did not exist before Netpbm 10.82 (March 2018).

SEE ALSO

       pnmcolormap(1),  pnmremap(1),  ppmquantall(1),  pamdepth(1),  ppmdither(1),   ppmquant(1),
       pnm(1)

DOCUMENT SOURCE

       This  manual page was generated by the Netpbm tool 'makeman' from HTML source.  The master
       documentation is at

              http://netpbm.sourceforge.net/doc/pnmquant.html