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ra_gif - convert RADIANCE picture to Compuserve GIF
ra_gif [ -b ][ -d ][ -c ncolors ][ -g gamma ][ -e +/-stops
][ -n sampfac ] input [ output ]
Ra_gif converts from RADIANCE to Compuserve GIF colormapped,
compressed image files. In the default mode, a
RADIANCE picture is converted to a color-mapped GIF file of
the same horizontal and vertical dimensions with 8-bits per
pixel. The -b option converts the image to black and white.
The -d option turns off dithering. The -c option allows
fewer than 256 colors (and fewer than 8 bits per pixel).
The -g option specifies the exponent used in gamma
correction; the default value is 2.2. An exponent of 1.0
turns gamma correction off. The -e option specifies an
exposure compensation in f-stops (powers of two). Only
integer stops are allowed, for efficiency. The -n option
specifies a sampling factor for neural network color
quantization. This value should be between 1 and 80, where
1 takes the longest and produces the best results in small
areas of the image. If no value is given, a faster median
cut algorithm is used. If the output file is missing, the
standard output is used.
Greg Ward
Paul Haeberli
David Rowley
Anthony Dekker provided the code for neural network color
quantization
pfilt(1), ra_bn(1), ra_ppm(1), ra_pr(1), ra_pr24(1),
ra_t8(1), ra_t16(1), ra_tiff(1), ximage(1)
Header and Footer
RA_GIF(1) RADIANCE (6/10/94) RA_GIF(1)
Page 1 (printed 7/17/96)
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