undo method

void undo()

Undo the last image action

Implementation

void undo() {
  if (_history[_currentPage]?.isNotEmpty == true) {
    var lastAction = _history[_currentPage]!.removeLast();
    _undoStack[_currentPage]!.add(lastAction);

    if (lastAction.isAdd) {
      _imageBoxes[_currentPage]?.remove(lastAction.imageBox);
    } else {
      _imageBoxes[_currentPage]?.add(lastAction.imageBox);
    }
    notifyListeners();
  }
}