Data structure and algorithm visualization (2) – DOT usage | August more challenges

Digraph /graph/subgraph, node and edge are used to describe the diagram/flow chart in DOT, and the drawing is completed with the setting of some properties.

1. Basic usage of graphs

The basic syntax of DOT is as follows:

Digraph /graph/subgraph graphName{label=" example "; bgcolor="beige" ...... }Copy the code

Digraph /graph/subgraph represents an undirected graph, a directed graph, and a subgraph, respectively. GraphName is the name of an image.

• digraphUsed to describe directed graphs, used in relation->To describe the
• graphUsed to describe undirected graphs, used in relation--To describe the
• labelandbgcolorIs a defined image property
• graphNameDefine the name of the image
• Comments are similar to C,// 和 #Comment a single line,/ * * /Multi-line comments.
• DOT can be written with a semicolon at the end and no quotes at the property.

Common graph properties

2. Node (nodeThe use of the)

Digraph demo {label=" example "bgcolor="beige" // Define node default property node[color="grey"] // define node root[label=" root ", Shape ="box"] left[label=" left child ", shape="box"] node[color="#FF6347"] right[label=" right child ", Shape ="ellipse"] root -> {left,right}[label=" parent "] left -> subnode[label=" parent "] {rank=same; left, right} }Copy the code

• root,left,right,subnodeFor the node. Nodes can be defined in advance as followsRoot [label=" root ", shape="box"], can also be used directly when defining edge relationshipsLeft -> subnode[label=" parent "].
• Node is used to define the default properties of a node, scoped from this definition to the next. The default values are overridden by properties set for a particular node.
• []Properties that can be set for graphs, nodes, and edges.
• rankDefinition sets the effect of nodes on the same line to assist in rendering the image.

Common node attributes

Shape sample

digraph demo {
    bgcolor="floralwhite"
    "box"[shape=box]
    "polygon"[shape=polygon,sides=7] 
    "ellipse"[shape=ellipse]
    "circle"[shape=circle]
    "point"[shape=point]
    "triangle"[shape=triangle]
    "invtriangle"[shape=invtriangle]
    "plaintext"[shape=plaintext]
    "diamond"[shape=diamond]
}
Copy the code

3, The use of edge

Digraph demo {label=" example "bgcolor="beige" // Define node default property node[color="grey"] // define node root[label=" root ", Shape ="box"] left[label=" left child ", shape="box"] node[color="#FF6347"] right[label=" right child ", Shape ="ellipse"] root -> {left,right}[label=" parent "] edge[color="#FF6347"] left -> subnode[label=" parent "]  {rank=same; left, right} }Copy the code

• Edge is used to define the default property of an edge. Similar to node, the scope is intercepted from one definition to the next. Properties set for a particular edge override the default values.

• Essentially, node and edge are also nodes, special nodes reserved to describe node attributes and edge attributes

• Undirected graph relations use — description, directed graph relations use -> description

Common edge attributes

Arrowhead sample

digraph demo { bgcolor="floralwhite" rankdir=LR "box"->"crow"[arrowhead=box] "crow"->"curve"[arrowhead=crow] "curve"->"diamond"[arrowhead=curve] "diamond"->"dot"[arrowhead=diamond] "dot"->"inv"[arrowhead=dot] "inv"->"none"[arrowhead=inv] "none"->"normal"[arrowhead=none] "normal"->"tee"[arrowhead=normal] [arrowhead=lcrowortee]} [arrowhead=lcrowortee]}Copy the code

4. Some examples

subgraph

A graph can contain multiple subgraphs, and subgraphs can also nest subgraphs. The subgraph name must be Cluster *, otherwise it will be rendered directly as a node.

digraph demo {
    bgcolor="beige"
    subgraph cluster_husband {
        node[color="grey"]
        {"Dad"."Mother"} - >"我"
    }
     subgraph cluster_wife {
         {"Father"."Mother-in-law"} - >"Wife"
     }
     "我" -> "Wife"[label="Husband and wife", dir="both"]
     {rank=same; "我"."Wife"}}Copy the code

Render as follows:

The list

digraph demo { bgcolor="beige" rankdir=LR; node [shape="record", Height = 0.1] node0 [label = "{< f1 > G | < f2 > next}"] node1 [label = "{< f1 > E | < f2 > next}"] node0: f2 - > node1: f1}Copy the code

• rankdir=LRDescribe the image as horizontal
• Separated by | served in mapped nodes show as a delimiter
• Strings enclosed in <> are called anchor points
• node0[label="{<f1> G | <f2> next}"], {} describes multiple segmentation bits and in the same noderankdirconsistent

B tree

digraph demo { bgcolor="beige" node [shape="record", height=.1] node0[label="<f1> A | <f2> B | <f3> C | <f4> "] node1[label="<f1> D | <f2> E | <f3> F"] node2[label="<f1> G |  <f2> H | <f3> I"] node0:f1 -> node1:f1 node0:f2 -> node2:f1 }Copy the code