tiffmedian - apply the median cut algorithm to data in a TIFF file
tiffmedian [
options ]
input.tif output.tif
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.
- -c
- Specify the compression to use for data written to the
output file: -c none for no compression, -c packbits for
PackBits compression, -c lzw for Lempel-Ziv & Welch
compression, -c 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),
tiff2cmp (1),
libtiff (3tiff),
"Color Image Quantization for Frame Buffer Display", Paul
Heckbert, SIGGRAPH proceedings, 1982, pp. 297-307.
LibTIFF contributors
1988-2023, LibTIFF contributors