NAME

       tiffmedian - apply the median cut algorithm to data in a TIFF file

SYNOPSIS

       tiffmedian [ options ] input.tif output.tif

DESCRIPTION

       tiffmedian applies the median cut algorithm to an RGB image in input.tif to generate a palette image that
       is  written  to  output.tif.   The  generated  colormap  has, by default, 256 entries.  The image data is
       quantized by mapping each pixel to the closest color values in the colormap.

OPTIONS

       -c     Specify the compression to use for data written to the  output  file:  none  for  no  compression,
              packbits  for  PackBits  compression,  lzw for Lempel-Ziv & Welch compression, and zip for Deflate
              compression.  By default tiffmedian will compress data according to the value of  the  Compression
              tag found in the source file.

              LZW  compression  can be specified together with a predictor value.  A predictor value of 2 causes
              each scanline of the output image to undergo horizontal differencing before it is encoded; a value
              of 1 forces each scanline to be encoded without differencing.  LZW-specific options are  specified
              by appending a ``:''-separated list to the ``lzw'' option; e.g.  -c lzw:2 for LZW compression with
              horizontal differencing.

       -C     Specify the number of entries to use in the generated colormap.  By default all 256 entries/colors
              are used.

       -f     Apply Floyd-Steinberg dithering before selecting a colormap entry.

       -r     Specify  the  number  of  rows  (scanlines)  in each strip of data written to the output file.  By
              default, tiffmedian attempts to set the rows/strip that no more than 8 kilobytes of data appear in
              a strip.

NOTES

       This program is derived from Paul Heckbert's median program.

SEE ALSO

       pal2rgb(1), tiffinfo(1), tiffcp(1), tiffcmp(1), libtiff(3TIFF)

       Color Image Quantization for Frame  Buffer  Display,  Paul  Heckbert,  SIGGRAPH  proceedings,  1982,  pp.
       297-307.

       Libtiff library home page: http://www.simplesystems.org/libtiff/

libtiff                                         November 2, 2005                                   TIFFMEDIAN(1)