zitadel/internal/ui/login/static/resources/scripts/avatar.js

const avatars = document.getElementsByClassName('lgn-avatar');
for (let i = 0; i < avatars.length; i++) {
  const displayName = avatars[i].getAttribute('loginname');
  if (displayName) {
    const username = displayName.split('@')[0];
    let separator = '_';
    if (username.includes('-')) {
      separator = '-';
    }
    if (username.includes('.')) {
      separator = '.';
    }
    const split = username.split(separator);
    const initials = split[0].charAt(0) + (split[1] ? split[1].charAt(0) : '');
    avatars[i].getElementsByClassName('initials')[0].innerHTML = initials;

    avatars[i].style.background = this.getColor(displayName);
    // set default white text instead of contrast text mode
    avatars[i].style.color = '#ffffff';
  }
}

function getColor(userName) {
  const colors = [
    'linear-gradient(40deg, #B44D51 30%, rgb(241,138,138))',
    'linear-gradient(40deg, #B75073 30%, rgb(234,96,143))',
    'linear-gradient(40deg, #84498E 30%, rgb(214,116,230))',
    'linear-gradient(40deg, #705998 30%, rgb(163,131,220))',
    'linear-gradient(40deg, #5C6598 30%, rgb(135,148,222))',
    'linear-gradient(40deg, #7F90D3 30%, rgb(181,196,247))',
    'linear-gradient(40deg, #3E93B9 30%, rgb(150,215,245))',
    'linear-gradient(40deg, #3494A0 30%, rgb(71,205,222))',
    'linear-gradient(40deg, #25716A 30%, rgb(58,185,173))',
    'linear-gradient(40deg, #427E41 30%, rgb(97,185,96))',
    'linear-gradient(40deg, #89A568 30%, rgb(176,212,133))',
    'linear-gradient(40deg, #90924D 30%, rgb(187,189,98))',
    'linear-gradient(40deg, #E2B032 30%, rgb(245,203,99))',
    'linear-gradient(40deg, #C97358 30%, rgb(245,148,118))',
    'linear-gradient(40deg, #6D5B54 30%, rgb(152,121,108))',
    'linear-gradient(40deg, #6B7980 30%, rgb(134,163,177))',
  ];

  let hash = 0;
  if (userName.length === 0) {
    return colors[hash];
  }

  hash = this.hashCode(userName);
  return colors[hash % colors.length];
}

function hashCode(str, seed = 0) {
  let h1 = 0xdeadbeef ^ seed, h2 = 0x41c6ce57 ^ seed;
  for (let i = 0, ch; i < str.length; i++) {
    ch = str.charCodeAt(i);
    h1 = Math.imul(h1 ^ ch, 2654435761);
    h2 = Math.imul(h2 ^ ch, 1597334677);
  }
  h1 = Math.imul(h1 ^ (h1 >>> 16), 2246822507) ^ Math.imul(h2 ^ (h2 >>> 13), 3266489909);
  h2 = Math.imul(h2 ^ (h2 >>> 16), 2246822507) ^ Math.imul(h1 ^ (h1 >>> 13), 3266489909);
  return 4294967296 * (2097151 & h2) + (h1 >>> 0);
}