我最近开始使用Graphviz。

我正在处理带有标签的图形，但是它们没有出现。我的子组也没有被矩形包围。

这是我的代码：

digraph system {

    subgraph Machine_001 {
        label = "Machine_001";

        subgraph Machine_001_Service_001 {
            label = "Service_001 on Machine_001";
            node [shape=record];

            Machine_001_PORT_10 [label = "Port 10"];
            Machine_001_PORT_11 [label = "Port 11"];
            Machine_001_PORT_12 [label = "Port 12"];
            Machine_001_PORT_13 [label = "Port 13"];

            {rank=same Machine_001_PORT_10 Machine_001_PORT_11 Machine_001_PORT_12 Machine_001_PORT_13}
            Machine_001_PORT_10 -> Machine_001_PORT_11;
            Machine_001_PORT_12;
            Machine_001_PORT_13;
        }
    }

    subgraph Machine_002 {
        label = "Machine_002";

        subgraph Machine_002_Service_001 {
            label = "Service_001 on Machine_002";
            node [shape=record];

            Machine_002_PORT_50  [label = "Port 50"];

            Machine_001_PORT_11 -> Machine_002_PORT_50;
        }
    }
}

我希望使用Roc来呈现它，但标签不会显示。

另一方面，这样的示例确实显示了标签和一个环绕的矩形：

digraph D {

  subgraph cluster_p {
    label = "Parent";

    subgraph cluster_c1 {
      label = "Child one";
      a;

      subgraph cluster_gc_1 {
        label = "Grand-Child one";
         b;
      }
      subgraph cluster_gc_2 {
        label = "Grand-Child two";
          c;
          d;
      }

    }

    subgraph cluster_c2 {
      label = "Child two";
      e;
    }
  }
}

坦白说，我看不出问题所在。我给它贴了标签，然后将其嵌套。工作示例正是这样做的。

我想念什么？