feature request: Add ability to set individual custom dot size

[WD-J]

An idea for an implementation could be something similar to the customMask impl, where you'd set size as such:

customDotSize: (r, c) {
  return const [
    [5, 0, 1, 0, 5],
    [5, 1, 1, 1, 5],
    [5, 1, 1, 1, 5],
    [5, 1, 1, 1, 5],
    [5, 0, 1, 0, 5],
  ];
},