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ra_pr - convert RADIANCE picture to/from pixrect rasterfile
ra_pr [ -d ][ -b ][ -c ncolors ][ -g gamma ][ -e +/-stops ]
input [ output ]
ra_pr -r [ -g gamma ][ -e +/-stops ] [ input [ output ] ]
Ra_pr converts between RADIANCE and pixrect rasterfile
formats. In the default mode, a RADIANCE picture is
converted to a pixrect rasterfile of the same horizontal and
vertical dimensions with 8-bits per pixel. The -d option
turns off dithering. The -b option converts the image to
black and white, for improved quality on greyscale monitors.
Only with this option can the input be taken from stdin.
The -c option allows fewer than 256 colors. 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 -r option invokes a reverse conversion,
from a pixrect rasterfile to a RADIANCE picture. If the
output file is missing, the standard output is used.
Greg Ward
Paul Heckbert provided the code for color quantization
Only standard 8-bit color rasterfiles are read or written.
pfilt(1), ra_bn(1), ra_ppm(1), ra_pr24(1), ra_t8(1),
ra_t16(1), ra_tiff(1), ximage(1)
Header and Footer
RA_PR(1) RADIANCE (11/15/93) RA_PR(1)
Page 1 (printed 7/17/96)
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