an <code>AnimationController</code>.</p>
    </section>
    
    <section class="summary source-code" id="source">
      <h2><span>Implementation</span></h2>
      <pre class="language-dart"><code class="language-dart">static Color lerp(Color a, Color b, double t) {
  assert(t != null);
  if (a == null &amp;&amp; b == null)
    return null;
  if (a == null)
    return _scaleAlpha(b, t);
  if (b == null)
    return _scaleAlpha(a, 1.0 - t);
  return new Color.fromARGB(
    lerpDouble(a.alpha, b.alpha, t).toIn