private void Redraw(IGameHandler handler)
 {
     handler.Clear();
     foreach (var cell in _cells.AsEnumerable())
     {
         int i = cell.Key.Item1 - _players[0].ViewportLeft;
         int j = cell.Key.Item2 - _players[0].ViewportTop;
         if (0 > i || i >= CellsCount || 0 > j || j >= CellsCount)
         {
             continue;
         }
         if (cell.Value == CellType.X)
         {
             handler.DrawX(i, j);
         }
         else
         {
             handler.DrawZero(i, j);
         }
     }
 }