xenial (1) ra_rgbe.1.gz

NAME

       ra_rgbe - convert between different RADIANCE picture types

SYNOPSIS

       ra_rgbe [ -r ][ -e +/-stops ][ -f ][ -n frameno ] [ input [ outspec ] ]

DESCRIPTION

       Ra_rgbe  converts  between  RADIANCE  run-length  encoded  and  flat  formats, and separates concatanated
       animation frames produced by rpict(1).  The -e option  specifies  an  exposure  compensation  in  f-stops
       (powers  of  two).   Only integer stops are allowed, for efficiency.  By default, ra_rgbe produces a flat
       RADIANCE picture file from any type of RADIANCE input picture.  The -r option causes ra_rgbe to produce a
       run-length encoded file instead.

       If  the input file consists of multiple animation frames as produced by rpict with the -S option, ra_rgbe
       will read each frame and write it to the output  file  created  by  calling  printf(3)  with  the  output
       specification and frame number as arguments.  If the output specification begins with an exclamation mark
       ('!'), then this interpreted as a command spec., which is also run through printf with the  frame  number
       to  get  the  final  command.  This command must accept a Radiance picture on its standard input, and may
       write results either to a file or to the standard output.  The -n option may be used to select a specific
       frame  for  output, and other frames in the input will be skipped.  Normally, all frames will be read and
       written.

       Ra_rgbe will report an error and exit if the target output file already exists, unless the -f  option  is
       given.   If the output file is missing, the standard output is used.  If the input file is missing or set
       to '-', the standard input is used.

NOTES

       The file format for RADIANCE pictures was changed between release 1.4 and release 2.0.  The older  format
       can  still  be read by all the programs, but only the newer format is produced.  This newer format cannot
       be read by RADIANCE software prior to release 2.0.

       Ra_rgbe provides some downward compatibility by producing files  that  can  be  read  by  older  RADIANCE
       software.   The  resultant  files are also easier to manipulate with programs designed to read raw raster
       data.

       The other use for ra_rgbe is as a quicker way to adjust the exposure of a RADIANCE picture than pfilt(1),
       since  ra_rgbe  only  allows  integer  f-stop  changes.  In this mode, ra_rgbe should be used with the -r
       option.

AUTHOR

       Greg Ward

ACKNOWLEDGEMENT

       Work on this program was initiated and sponsored by the LESO group at EPFL in Switzerland.

SEE ALSO

       pfilt(1), printf(1), ra_xyze(1), rpict(1)