TIFFMEDIAN(1)							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  compres-
	      sion,  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 out-
	      put image to  undergo  horizontal	 differencing  before  it  is
	      encoded;	a value of 1 forces each scanline to be encoded with-
	      out  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(3)

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



			       October 15, 1995			TIFFMEDIAN(1)

UNIX/Linux commands referenced on this page:

1. cut
2. zip
3. strip
4. more