问题:

This may be related to How to place edge labels ON edge in graphviz: I have the following graph, which I visualize using the command dot -Teps g.dot > g.eps:

graph triple {
    node [shape=box]; User; Object; Tag;
    node [shape=diamond,style=filled]; Triple;
    {
        User -- Triple [label = "1"];
        Object -- Triple [label = "1"];
    }
    {
        rank=same;
        User;
        Object;
    }
    Triple -- Tag [label="n"];
}

I would like the result to be more symmetric by putting the label between User and Triple on the left side of the graph.

回答1:

And here's the second workaround using splines=false and double edges:

graph {
splines=false;
node [shape=box]; User; Object; Tag;
node [shape=diamond,style=filled]; Triple;
    {
        User   -- Triple [label = "1"];
        User   -- Triple [label = ""];
        Object -- Triple [label = ""];
        Object -- Triple [label = "1"];
    }
    {
        rank=same;
        User;
        Object;
    }
    Triple -- Tag [label="n"];
}

Output:

回答2:

Manual placement of edge labels cannot be done with graphviz.

However, you could use the headlabel, labeldistance and labelangle attributes:

graph triple {
node [shape=box]; User; Object; Tag;
node [shape=diamond,style=filled]; Triple;
    {
        User   -- Triple [headlabel = "1", labeldistance=2.5, labelangle=20];
        Object -- Triple [headlabel = "1", labeldistance=2.5, labelangle=-20];
    }
    {
        rank=same;
        User;
        Object;
    }
    Triple -- Tag [label="n"];
}

Output: