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RASFILTER8TO1(1)            General Commands Manual           RASFILTER8TO1(1)



NAME
       rasfilter8to1  -  convert  an  8-bit  deep  rasterfile  to a 1-bit deep
       rasterfile

SYNOPSIS
       rasfilter8to1 [ -d ] [ -rgba threshold ]
            [ infile [ outfile ]]

DESCRIPTION
       rasfilter8to1 reads the 8-bit  deep  rasterfile  infile  (the  standard
       input  default)  and  converts  it to the 1-bit deep rasterfile outfile
       (standard output default) by thresholding or ordered dither.  The  out-
       put  format  is  Sun  standard  rasterfile format (see <&lt;rasterfile.h>&gt;).
       This command is useful for viewing 8-bit rasterfiles  on  devices  that
       can only display monochrome images.

OPTIONS
       -d     Use  ordered dither to convert the input file instead of thresh-
              olding.

       -rgba threshold
              Set the threshold for the red, green, blue,  and  average  pixel
              color  values.   Pixels  whose  color values are greater than or
              equal to all of the thresholds are given a value of 0 (white) in
              the  output  rasterfile; other pixels are set to 1 (black).  The
              average threshold defaults to 128, the individual thresholds  to
              zero.

EXAMPLE
       The command

              example%  screendump -f  /dev/cgtwo | rasfilter8to1 | lpr -Pver-
              satec -v

       prints a monochromatic representation of the /dev/cgtwo frame buffer on
       the  printer  named versatec using the v output filter (see /etc/print-
       cap).  The printer must support an appropriate imaging  model  such  as
       PostScript in order to print the image.

FILES
       /usr/lib/rasfilters/*
                           filters for non-standard rasterfile formats

SEE ALSO
       lpr(1), rastrepl(1), screendump(1), screenload(1)

                               8 September 1988               RASFILTER8TO1(1)