undo method

Future<void> undo()

Implementation

Future<void> undo() async {
  final UPdfEdit? edit = _edit;
  if (edit == null || _undoStack.isEmpty) return;
  final int number = _undoStack.removeLast();
  for (int page = 0; page < viewer.pageCount; page++) {
    final List<UPdfAnnotationInfo> list = await edit.annotations(page);
    if (list.any((UPdfAnnotationInfo info) => info.objectNumber == number)) {
      await edit.removeAnnotation(page, number);
      viewer.invalidatePage(page);
      break;
    }
  }
  notifyListeners();
}