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.remotesensing.org/libtiff/