List<BoxShadow> lerpList(List<BoxShadow> a, List<BoxShadow> b, double t)

Linearly interpolate between two lists of box shadows.

If the lists differ in length, excess items are lerped with null.

Source 

static List<BoxShadow> lerpList(List<BoxShadow> a, List<BoxShadow> b, double t) {
  if (a == null && b == null)
    return null;
  if (a == null)
    a = new List<BoxShadow>();
  if (b == null)
    b = new List<BoxShadow>();
  List<BoxShadow> result = new List<BoxShadow>();
  int commonLength = math.min(a.length, b.length);
  for (int i = 0; i < commonLength; ++i)
    result.add(BoxShadow.lerp(a[i], b[i], t));
  for (int i = commonLength; i < a.length; ++i)
    result.add(a[i].scale(1.0 - t));
  for (int i = commonLength; i < b.length; ++i)
    result.add(b[i].scale(t));
  return result;
}