term% cat index.txt QUANTIZE(9.1) QUANTIZE(9.1)
NAME
3to1, mcut, improve, quantize, dither - picture color compression
SYNOPSIS
fb/3to1 [ -e ] colormap [ input ]
fb/mcut [ input ]
fb/improve colormap [ input ]
fb/quantize [ input ]
fb/dither [ input ]
DESCRIPTION
3to1 approximates the full color (3 bytes per pixel) or mapped (1 byte
per pixel, possibly with a colormap) input picture file in one byte per
pixel using the given colormap. If no input file is named, the picture
is read from standard input. The -e option suppresses the default er‐
ror-diffusion dither.
Mcut writes a color map, suitable for use by 3to1 on its standard out‐
put. The color map is computed using the median-cut algorithm and rep‐
resents reasonably well, but not necessarily optimally, the colors of
the input picture.
Improve reads a color map and a picture and writes on standard output a
new color map that better represents the colors of the picture. Multi‐
ple passes of improve may produce better and better color maps.
Quantize is an rc script that packages all of the above to compress the
full-color input image to one byte per pixel.
Dither likewise compresses full-color images to one byte per pixel. It
uses a fixed color map that allows a speedy algorithm; quantize instead
runs slower but gives better results.
SOURCE
/sys/src/fb/3to1.c
/sys/src/fb/mcut.c
/sys/src/fb/improve.c
/sys/src/fb/quantize.r
/sys/src/fb/dither.c
SEE ALSO
picfile(9.6), cmap(9.6)
QUANTIZE(9.1)