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quantize(9) [plan9 man page]

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 output.  The color map is computed using the median-cut algorithm and
       represents 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.
       Multiple 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)

Check Out this Related Man Page

PCP(9.1)																  PCP(9.1)

NAME

       pcp - copy pictures

SYNOPSIS

       fb/pcp [ -wx0 y0 x1 y1 ] [ -ox y ] [ -ttype ] [ -cchannels ] [ -Cchannels ] [ -mcolormap ] [ -M ] [ input [ output ] ]

DESCRIPTION

       Pcp  copies  the  input	picture (default standard input) to the output file (default standard output).	Options control the attributes and
       content of the output picture.

       -w x0 y0 x1 y1
	      causes only the given window of the input picture to be copied.  By default the whole picture is copied.

       -o x y causes the output picture's WINDOW= attribute to be translated by adding (x,y) to the input window coordinates.

       -t type
	      sets the TYPE= attribute of the output file.  The default is to use the input file's type.

       -c channels
	      causes only the given channels of the input picture to be copied.  The default is to copy all channels.  If channels not present	in
	      the  input  picture  are specified, they are computed in the ``most plausible'' way.  For example, a missing alpha channel is set to
	      255, and an m channel will be synthesized from rgb channels by computing NTSC luminance.	A 0 in channels causes a zero  channel	to
	      be written.

       -C channels
	      sets the output CHAN= attribute.	Channels must be the same length as the selected channels of the input picture.

       -m colormap
	      attaches the given color map to the output.

       -M     elides the color map from the output.

SOURCE

       /sys/src/fb/pcp.c

SEE ALSO

       picfile(9.6), cmap(9.6)

																	  PCP(9.1)
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