#!/usr/bin/perl
#
# color_lookup  colorname...
#
# Locate the RGB table (dbm or ascii)
# Order here if from lowest to highest preference
foreach $dir ( "/usr/openwin/lib",    "/usr/lib/X11",
              "/usr/X11R6/lib/X11", "/usr/X11R6.1/lib/X11" ) {
   $RGB  = "$dir/rgb"       if -f "$dir/rgb.dir";
   $RGBT = "$dir/rgb.txt"   if -f "$dir/rgb.txt";
}
#
# what environment variable should this be? I have not found one.
# $RGB = $ENV{'?????'}
#         if  defined  $ENV{'?????'} && -f $ENV{'?????'};
#

die("RGB database not found!\n")   unless $RGB || $RGBT;

# this only should be done once in a program
if ( defined $RGB ) {
  dbmopen(%RGB, $RGB, undef) || die "Unable to open RGB database\n";
} else {
  open(RGB, $RGBT)
    or die "Unable to open RGB text database, \"$RGBT\"\n";
}

COLOR:
while( $color = shift ) {

  if ( defined $RGB ) {
    $color_rgb  = $RGB{ "\L$color" };

    if ( defined $color_rgb ) {
      # $color_rgb  = join('', unpack( "H12", $color_rgb));       # 16 bits/chan
        $color_rgb  = join('', unpack( "H2xH2xH2x", $color_rgb)); # 8
        printf "Color %-20s --> #%s\n", "\"$color\"", $color_rgb;
        exec( qw{ display -size 100x100 }, "xc:#$color", '&' )
          if $ENV{DISPLAY};
        next COLOR;
    }
  } else {
    seek(RGB, 0, 0);   # rewind RGB text file
    while( <RGB> ) {
      next   if /^!/;   # ignore rgb.txt comments
      s/^\s+//;         # remove start spaces (if present)
      s/\s+$//;         # remove end of line junk
      ($r,$g,$b,$c) = split(/\s+/,$_,4);
      if ( lc($color) eq lc($c) ) {
        printf "Color %-20s --> #%02x%02x%02x  or  %3d %3d %3d\n",
                 "\"$color\"", $r, $g, $b, $r, $g, $b;
        exec( qw{ display -size 100x100 },
                sprintf("xc:#%02x%02x%02x",$r, $g, $b), '&' )
          if $ENV{DISPLAY};
        next COLOR;
      }
    }
  }
  print "No such Color \"$color\" found\n";
}