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 color-mapped, 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.
Anthony Dekker provided the code for neural network color quantization
pfilt(1), ra_bmp(1), ra_bn(1), ra_ppm(1), ra_pr(1), ra_pr24(1), ra_t8(1), ra_t16(1), ra_tiff(1), ximage(1)