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TIFFMEDIAN(1)          DragonFly General Commands Manual         TIFFMEDIAN(1)


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)

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