wavy-canvas/src/offsetParent.js

Create a wave animation on the canvas

/**
 * @param {HTMLElement} parent
 * @param {HTMLElement} child
 * @returns {{x: number, y: number}}
 */
export default function offsetParent(parent, child) {
  var pRect = parent.getBoundingClientRect();
  var cRect = child.getBoundingClientRect();

  return {
    x: -(pRect.left - cRect.left - cRect.width / 2),
    y: -(pRect.top - cRect.top - cRect.height / 2)
  };
}