Radiance 3.5 User Manual

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ra_pr (1)


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)
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