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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
       error-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)