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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)

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PIC2PS(9.1)															       PIC2PS(9.1)

NAME
pic2ps, pic2gif - convert picture files to other formats SYNOPSIS
fb/pic2ps [ -c ] [ -h height ] [ input ] fb/pic2gif [ -i ] [ -l ] [ -b depth ] [ input ] DESCRIPTION
Pic2ps converts its input image (default standard input) into encapsulated PostScript, writing the result to standard output. If the input image is full-color, its luminance is computed first, except under option -c, which produces output suitable for a color PostScript printer. Option -h sets the output image height in inches. The default height is 3", to match the default height of the .BP macro in troff -mpictures. Pic2gif converts its input image (default standard input) into a Compuserv GIF format file, writing the result to standard output. It con- verts only the first channel of the input image, which may yield wrong results -- use the -l flag or quantize(9.1) or some other dithering filter to reduce color images to a single channel. Option -i produces an interlaced output file. Option -b sets the number of bits per pixel in the output file. The default is 8, which is the maximum. Option -l makes pic2gif compute the NTSC luminance of its input. If pic2gif's input contains no color map, it assumes that it is a 256 grey shade monochrome image. SOURCE
/sys/src/fb/pic2ps.c /sys/src/fb/pic2gif.c SEE ALSO
mpictures(6), picfile(9.6), quantize(9.1), PIC2PS(9.1)
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