#!/usr/bin/perl
# -*- perl -*-
# Copyright 2001 DJ Delorie <dj@delorie.com>

if ($ARGV[0] eq "show-source") {
  print "Content-type: text/plain\n\n";
  print `cat chord-radius.cgi`;
  exit;
}

require "./woodlib.pl";

print "Content-type: text/html\n\n";
print `header Chord/Radius Calculations`;

$chord = $in{'chord'};
$div = $in{'div'};
$offset = $in{'offset'};

$chord = &unfrac($chord);
$offset = &unfrac($offset);

if ($chord <= 0 || ($div != 1 && $div != 2) || $offset <= 0) {
    print "<pre>Invalid chord ($chord) divisor ($div) or offset ($offset)\n";
    exit 1;
}

$chord /= $div;

print "<pre>\n";
printf "Chord: %s end-center\n", &frac($chord);
printf "       %s end-end\n\n", &frac($chord * 2);
printf "Offset: %s\n\n", &frac($offset);

$radius = ($chord * $chord + $offset * $offset) / (2 * $offset);

printf "Radius: %s  (%s)\n", &frac($radius), $radius;

printf "Chord to center: %s  (%s)\n", &frac($radius - $offset), $radius - $offset;

print "</pre>\n";

print `trailer`;