#! /bin/gawk -f
# Last edited on 2003-04-07 12:55:42 by stolfi

BEGIN {
  usage = ( \
    "draw-gridpoints \\\n" \
    "  [ -v scale=NUM ] \\\n" \
    "  < image.grpts > image.pcmds" \
  );
  
  # Outputs a string of commands, suitable as the "-draw" option
  # of "convert", that draws circles around the reference points
  # Assumes that it will be used on a copy of the image that has been
  # scaled by {scale}.

  abort = -1;
}

(abort >= 0) { exit abort; }

($6 ~ /^grid[0-9][0-9]/) {
  if (($5 + 0) != 0) { data_error(("bad Z = \"" $5 "\"")); }
  h = int(scale*$1);
  v = int(scale*$2);
  x = $3;
  y = $4;
  z = $5;
  printf "circle %d,%d %d,%d text %d,%d \"%d,%d\"\n", 
    h,v, h+2,v, h+4,v+3, int(x/10 + 0.5), int(y/10 + 0.5);
}

END {
  if (abort >= 0) { exit abort; }
}

function data_error(msg)
{ printf "%d: **%s\n", FNR, msg > "/dev/stderr"; 
  abort = 1; exit abort;
}

function arg_error(msg)
{ printf "**%s\n", msg > "/dev/stderr"; 
  abort = 1; exit abort;
}