undo method

Future<void> undo()

Implementation

Future<void> undo() async {
  if (points.isEmpty) return;
  final int index = points.length - 1;
  points.removeLast();
  await controller.removeNode("p$index");
  if (index > 0) {
    await controller.removeNode("l${index - 1}");
    await controller.untrack("m${index - 1}");
  }
  if (points.isEmpty) {
    await controller.removeNode("preview");
    _previewReady = false;
  }
  await _updateClosing();
  _notify();
}