graphviz - 在 Graphviz 中的子图下添加标签

Question

我使用以下代码在 Graphviz 中使用点生成图形。我手动包含了节点的坐标，因为我需要四个不相交的子图彼此相邻放置，如图所示。


我想在每个子图下添加标签:$G_0$、$G_1$ 等。在子图下添加标签会创建一个框并忽略我的坐标对齐。有没有其他方法，比如在指定坐标处放置任意文本？我使用“dot -Teps -Kfdp -n tree -o t.eps”进行编译。

digraph Trees {
node [shape=circle, style="filled", fixedsize=true,width=0.6];  0; 1;2; 3;4; 5;6; 7; 8;9;10;11;12;13;14;15;
0[pos = "0,1!"]
1[fillcolor=red, pos = "-1,2!"]
2[pos = "1,2!"]
3 [pos = "0,-0.5!"]
5[label=1, fillcolor=red, pos = "2,2!"]
4[label=0, fillcolor=red, pos = "3,1!"]
6[label=2, pos = "4,2!"]
7[label=3, pos = "3, -0.5!"]
9[label=1, fillcolor=red, pos = "5,2!"]
8[label=0, fillcolor=red, pos = "6,1!"]
10[label=2, pos = "7,2!"]
11[label=3, fillcolor=red, pos = "6, -0.5!"]
12[label=1, fillcolor=red, pos = "8,2!"]
13[label=0, fillcolor=green, pos = "9,1!"]
14[label=2, pos = "10, 2!"]
15[label=3, fillcolor=green, pos = "9, -0.5!"]

overlap=false;
fontsize=10;

subgraph 1{
  edge [dir=none] 1->0 2->0 3->0;
}

subgraph 2{
  edge [color=red] 5->4;
  edge[color=black, dir=none] 6->4 7->4;
}

subgraph 3{
  edge [color=red] 9->8 8->11;
  edge [color=black, dir=none] 8->10;
}

subgraph 4{
  edge [color=green] 12->13; 13->15;
  edge [color=black, dir=none] 13->14;
}
}

Answer 1

可以使用集群和点布局引擎使子图不相交。同样的方法也将允许引入集群标签。它们可以根据需要放置在集群的底部，而无需创建虚拟节点。

这样就不需要绝对位置，而且即使添加了其他节点也会自动生成布局。节点的确切位置发生了变化，但图的拓扑结构保持不变。

digraph Trees { node [shape = circle, style = "filled", fixedsize = true, width=0.4]; 
    edge [dir = none];
    layout = dot; overlap = false; fontsize = 10;
    graph [labelloc = "b", penwidth = 0];
    {   node [fillcolor = "red"];
        1; 5 [label = 1]; 4 [label = 0]; 9 [label = 1]; 
        8 [label = 0]; 11 [label = 3]; 12 [label = 1]; 
    }

    2; 0; 3; 6 [label = 2]; 7 [label = 3];
    10 [label = 2]; 14 [label = 2]; 
    {   node [fillcolor = "green"];
        13 [label = 0]; 15 [label = 3];
    }
    subgraph cluster1{ 
        label = "Subgraph 1"; 
        { 1; 2; } -> 0 -> 3; 
    }
    subgraph cluster2{ 
        label = "Subgraph 2"; 
        5 -> 4 [color = red, dir = fwd]; 
        6 -> 4 -> 7; 
    }
    subgraph cluster3{ 
        label = "Subgraph 3"; 
        9 -> 8-> 11 [color=red, dir = fwd]; 
        10 -> 8 [color=black]; 
    }
    subgraph cluster4{ 
        label = "Subgraph 4"; 
        12 -> 13 -> 15 [color=green, dir = fwd]; 
        14-> 13; 
    } 
}