#! /usr/bin/gawk -f
# Last edited on 2018-06-16 23:47:12 by jstolfi
# Converts pixel coordinates copied from a chart image to points in proper units.

/^[ ]*([#]|$)/ { 
  # Comment/blank:
  print; 
  next; 
} 

/^[=]/ { 
  # Scale definition: 
  x0=$2; y0=$3; t0=$4; p0=$5; x1=$6; y1=$7; t1=$8; p1=$9;
  print; 
  next;
} 

// { 
  # Remove any previously mapped values: 
  gsub(/[ ]*[#][#].*$/, "", $0);
}

/^[*]/ { 
  t = xsc($2); p = ysc($3); 
  printf "%s ## %6.2f %6.2f\n", $0, t, p; 
  next; 
} 
/^[-]/ { 
  ta = xsc($2); pa = ysc($3); 
  tb = xsc($4); pb = ysc($5); 
  printf "%s ## %6.2f %6.2f %6.2f %6.2f\n", $0, ta, pa, tb, pb; 
  next; 
} 
//{ 
  # Duh?
  print "%s ## ** ERROR\n", $0;
  next;
}

function xsc(x) { return t0 + (x-x0)*(t1-t0)/(x1-x0); }
function ysc(y) { return p0 + (y-y0)*(p1-p0)/(y1-y0); }