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tiffmedian - apply the median cut algorithm
to data in a TIFF
file
tiffmedian [ options ] input.tif output.tif
tiffmedian applys 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.
- -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.
This program is derived from Paul Heckbert's median program.
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.
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