graphviz

Question

也许我比我应该更努力地弯曲 graphviz，但是它会吗可以拉直箭头吗？我需要标签在箭头上方，而不是像 label/xlabel 那样在旁边；我使用盒子来保存本质上是标签文本的内容，因为在标签很长的时候在边缘使用标签似乎会导致古怪的行为。

digraph G {
    node [shape=rect style=filled
         fontcolor=white fontsize=12 fontname="Helvetica Bold"]
    edge [style=solid color="#777777"]

    // introduce nodes; set fill
    a1, a2, a3 [fillcolor="#438dd5"]
    c1         [fillcolor="#08427b"]

    b1, b2, b3 [fillcolor=white fontcolor=black fontname="Helvetica" shape=plain]

    a1 -> b1[dir=none]
    a2 -> b2[dir=none]
    a3 -> b3[dir=none]

    b1 -> c1
    b2 -> c1
    b3 -> c1

    { rankdir=LR  rank=same  a1 a2 a3  }
    { rankdir=LR  rank=same  b1 b2 b3 }
    { rankdir=LR  rank=same  c1 }
}

我得到的：

我想要的：

Answer 1

我通常使用 tables with no borders and white background instead of labels. You would probably also need to use headlabel or taillabel, because in this case you can precisely control their position with labeldistance and labelangle:

digraph G {
    node  [shape=rect style=filled
           fontcolor=white fontsize=12 fontname="Helvetica Bold"]
    graph [ranksep=1]
    edge  [style=solid color="#777777"]

    a1 [fillcolor="#438dd5"]
    a2 [fillcolor="#438dd5"]
    a3 [fillcolor="#438dd5"]
    c1 [fillcolor="#08427b"]

    a1 -> c1 [
        labeldistance=5
        labelangle=0
        headlabel=<
            <table bgcolor="white" border="0">
                <tr>
                    <td>b1</td>
                </tr>
            </table>
        >
    ]
    a2 -> c1 [
        labeldistance=4
        labelangle=0
        headlabel=<
            <table bgcolor="white" border="0">
                <tr>
                    <td>b2</td>
                </tr>
            </table>
        >
    ]
    a3 -> c1 [
        labeldistance=5
        labelangle=0
        headlabel=<
            <table bgcolor="white" border="0">
                <tr>
                    <td>b3</td>
                </tr>
            </table>
        >
    ]
}

结果：

graphviz - 如何在直箭头上创建标签

graphviz - how to create labels over straight arrows