@phaserjs/phaser/geom/ellipse/GetEllipseCircumference.js

Phaser 4

/**
 * @author       Richard Davey <rich@photonstorm.com>
 * @copyright    2020 Photon Storm Ltd.
 * @license      {@link https://opensource.org/licenses/MIT|MIT License}
 */
export function GetEllipseCircumference(ellipse) {
  const rx = ellipse.width / 2;
  const ry = ellipse.height / 2;
  const h = Math.pow(rx - ry, 2) / Math.pow(rx + ry, 2);
  return Math.PI * (rx + ry) * (1 + 3 * h / (10 + Math.sqrt(4 - 3 * h)));
}