xenial (1) ra_t8.1.gz

NAME

       ra_t8 - convert RADIANCE picture to/from Targa 8-bit image file

SYNOPSIS

       ra_t8 [ -d ][ -b ][ -c ncolors ][ -g gamma ][ -e +/-stops ][ -n sampfac ] input [ output ]
       ra_t8 -r [ -g gamma ][ -e +/-stops ] [ input [ output ] ]

DESCRIPTION

       Ra_t8   converts  between  RADIANCE  and  Targa  8-bit  color-mapped  image  files  (type  1  in  Targa's
       documentation).  In the default mode, a RADIANCE picture is converted to a color-mapped Targa file 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.  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 -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.  The -r  option  invokes  a  reverse
       conversion,  from an 8-bit Targa file to a RADIANCE picture.  If the output file is missing, the standard
       output is used.

AUTHORS

       Greg Ward
       Anthony Dekker provided the code for neural network color quantization

BUGS

       Run-length encoded files can be read but not written with this program.

SEE ALSO

       pfilt(1), ra_bmp(1), ra_bn(1), ra_ppm(1), ra_pr(1), ra_pr24(1), ra_t16(1), ra_tiff(1), ximage(1)