undo method

void undo()

Undo Last Change

Implementation

void undo() {
  int count = 0;
  while (true) {
    //print('TransState=$canUndo');
    if (canUndo == false) {
      break;
    }
    count++;
    final change = _history.removeLast();
    //print('TransState=${change.transState}');
    change.undoExecute();
    _redos.addFirst(change);
    //lastChanged = change;
    if (change.transState == TransState.none || change.transState == TransState.start) {
      if (count > 1 && change.mid.isNotEmpty) {
        //print('undo endTrans call save ----------------------');
        saveManagerHolder!.pushChanged(change.mid, 'undo endTrans');
      }
      break;
    }
  }
}