digraph G {
    /*全局设定*/
    graph [label=".dot图例-元素约定",
        labeljust="l",labelloc="t",center=1,
        ranksep=0.2,ratio=compress,
        rankdir=TB,
        ];

    node[fontsize=10.0,
        height=0.1,
        style=filled,fillcolor=snow,
        color=darkolivegreen,fontcolor=darkolivegreen,
        shape=plaintext,
        ];

    edge [fontsize=9.0,fontcolor=yellowgreen,
        color=gray30,
        ];

    /*图元声明*/
    start       [label="流程开始/结束",shape=point];
    end         [label="",shape=doublecircle,fillcolor=red];

    box         [label="实体/对象",shape=box];
    ellipse     [label="行动/节点",shape=ellipse];
    egg         [label="用户/人物",shape=egg];
    plaintext   [label="状态/属性",shape=plaintext,fillcolor=whitesmoke];
    diamond     [label="判别",shape=diamond];
    note        [label="注释",shape=note];
    tab         [label="目录/模块",shape=tab];
    db          [label="数据库",shape=box3d];
    component   [label="主机/组件",shape=component];
    
    /*图例关系*/
}