SVG arc

arc.js

function arc(x, y, rx, ry, from, to) {
  var ar = from * Math.PI / 180;
  var ax = x + rx * Math.cos(ar);
  var ay = y + ry * Math.sin(ar);

  var br = to * Math.PI / 180;
  var bx = x + rx * Math.cos(br);
  var by = y + ry * Math.sin(br);

  var sweep = (to - from) > 180 ? 1 : 0;

  return (
    ' M ' + ax + ' ' + ay +
    ' A ' + rx + ' ' + ry + ' 0 ' + sweep +
    ' 1 ' + bx + ' ' + by);
}