ilios/frontend

//Code from https://www.sitepoint.com/javascript-generate-lighter-darker-color/
export default function colorChange(hex, lum) {
  // validate hex string
  hex = String(hex).replace(/[^0-9a-f]/gi, '');
  if (hex.length < 6) {
    hex = hex[0] + hex[0] + hex[1] + hex[1] + hex[2] + hex[2];
  }
  lum = lum || 0;
  // convert to decimal and change luminosity
  let rgb = '#';
  for (let i = 0; i < 3; i++) {
    let c = parseInt(hex.substr(i * 2, 2), 16);
    c = Math.round(Math.min(Math.max(0, c + c * lum), 255)).toString(16);
    rgb += ('00' + c).substr(c.length);
  }

  return rgb;
}