NAME
rlequant - variance based color quantization
for RLE images
SYNOPSIS
rlequant [ -b bits ] [ -c ] [ -d ] [ -f ] [ -m ] [ -n colors ] [ -o
outfile ] [ infile ]
DESCRIPTION
This program quantizes the colors in an RLE
image using a variance-based method. See
colorquant(3) for more details on the method.
-b bits
The colors in the input image will be
"prequantized" to this many bits before
applying the variance-based method. Two
internal tables of size 2^(3*bits) are
allocated, so values of bits greater
than 6 are likely to cause thrashing or
may prevent the program from running at
all. The default value of bits is 5.
It must be less than or equal to 8 and
greater than 0.
-c Only the color map will be output; the
image will not be digitized. The output
file will be a 0x0 RLE file with a color
map, suitable for input to rleldmap(1)
or rledither(1).
-d Floyd Steinberg dithering is performed
on the output. This is very helpful for
images being quantized to a small number
of colors.
-f If this option is specified, a faster
approximation will be used. In most
cases, the error so introduced will be
barely noticeable.
-m Computes a single color map suitable for
quantizing all the input images. This
is useful when the quantized images will
be used as a "movie" (e.g., with the -m
flag of getx11(1)). The input may not
come from a pipe when this option is
specified, unless -c is also specified.
-n colors
The output image will be quantized to at
most colors colors. It might have fewer
if the input image has only a few colors
itself. The default value of colors is
256. It must be less than or equal to
256.
-o outfile
The output will be written to the file
outfile. If not specified, or if
outfile is "-", the output will be
written to the standard output stream.
infile
This file contains one or more
concatenated RLE images. Each will be
processed in turn. A separate
quantization map will be constructed for
each image. If not specified, or if
infile is "-", the image(s) will be read
from the standard input stream.
SEE ALSO
mcut(1), rledither(1), urt(1), colorquant(3),
RLE(5).
AUTHOR
Spencer W. Thomas
Craig Kolb (Yale University) wrote the color
quantization code.
Rod Bogart wrote the dithering code.
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