Diagrams¶

Diagrams help to communicate complex relationships and interconnections between different technical components, and are a great addition to project documentation. Material for MkDocs integrates with Mermaid.js, a very popular and flexible solution for drawing diagrams.

Configuration¶

SuperFences¶

Source · Experimental · Insiders only

The SuperFences extension, which is part of Python Markdown Extensions, allows for adding custom fences, which can be used to render Mermaid.js diagrams with zero effort:

markdown_extensions:
  - pymdownx.superfences:
      custom_fences:
        - name: mermaid
          class: mermaid
          format: !!python/name:pymdownx.superfences.fence_code_format

No further configuration is necessary. Material for MkDocs will automatically load and initialize the Mermaid.js runtime when a page includes a fenced mermaid block. Furthermore:

• Works with instant loading without any additional effort
• Diagrams automatically use fonts and colors defined in mkdocs.yml¹
• Fonts and colors can be customized with additional stylesheets
• Support for both, light and dark color schemes

While it's also possible to integrate Mermaid.js using existing third-party plugins², the new native integration is recommended as it ensures interoperability with all Material for MkDocs features.

Usage¶

Mermaid diagrams are written as code blocks with the help of the SuperFences extension. They must be enclosed with two separate lines containing three backticks.

Using flowcharts¶

Flowcharts are diagrams that represent workflows or processes. The steps are rendered as nodes of various kinds and are connected by edges, describing the necessary order of steps.

Example:

``` mermaid
graph LR
  A[Start] --> B{Error?};
  B -->|Yes| C[Hmm...];
  C --> D[Debug];
  D --> B;
  B ---->|No| E[Yay!];
```

Result:

graph LR
  A[Start] --> B{Error?};
  B -->|Yes| C[Hmm...];
  C --> D[Debug];
  D --> B;
  B ---->|No| E[Yay!];

Using sequence diagrams¶

Sequence diagrams describe a specific scenario as sequential interactions between multiple objects or actors, including the messages that are exchanged between those actors.

Example:

``` mermaid
sequenceDiagram
  Alice->>John: Hello John, how are you?
  loop Healthcheck
      John->>John: Fight against hypochondria
  end
  Note right of John: Rational thoughts!
  John-->>Alice: Great!
  John->>Bob: How about you?
  Bob-->>John: Jolly good!
```

Result:

sequenceDiagram
  Alice->>John: Hello John, how are you?
  loop Healthcheck
      John->>John: Fight against hypochondria
  end
  Note right of John: Rational thoughts!
  John-->>Alice: Great!
  John->>Bob: How about you?
  Bob-->>John: Jolly good!

Using state diagrams¶

State diagrams are a great tool to describe the behavior of a system, decomposing it into a finite number of states, and transitions between those states.

Example:

``` mermaid
stateDiagram-v2
  [*] --> Active

  state Active {
    [*] --> NumLockOff
    NumLockOff --> NumLockOn : EvNumLockPressed
    NumLockOn --> NumLockOff : EvNumLockPressed
    --
    [*] --> CapsLockOff
    CapsLockOff --> CapsLockOn : EvCapsLockPressed
    CapsLockOn --> CapsLockOff : EvCapsLockPressed
    --
    [*] --> ScrollLockOff
    ScrollLockOff --> ScrollLockOn : EvScrollLockPressed
    ScrollLockOn --> ScrollLockOff : EvScrollLockPressed
  }
```

Result:

stateDiagram-v2
  [*] --> Active

  state Active {
    [*] --> NumLockOff
    NumLockOff --> NumLockOn : EvNumLockPressed
    NumLockOn --> NumLockOff : EvNumLockPressed
    --
    [*] --> CapsLockOff
    CapsLockOff --> CapsLockOn : EvCapsLockPressed
    CapsLockOn --> CapsLockOff : EvCapsLockPressed
    --
    [*] --> ScrollLockOff
    ScrollLockOff --> ScrollLockOn : EvScrollLockPressed
    ScrollLockOn --> ScrollLockOff : EvScrollLockPressed
  }

Using class diagrams¶

Class diagrams are central to object oriented programing, describing the structure of a system by modelling entities as classes and relationships between them.

Example:

``` mermaid
classDiagram
  Person <|-- Student
  Person <|-- Professor
  Person : +String name
  Person : +String phoneNumber
  Person : +String emailAddress
  Person: +purchaseParkingPass()
  Address "1" <-- "0..1" Person:lives at
  class Student{
    +int studentNumber
    +int averageMark
    +isEligibleToEnrol()
    +getSeminarsTaken()
  }
  class Professor{
    +int salary
  }
  class Address{
    +String street
    +String city
    +String state
    +int postalCode
    +String country
    -validate()
    +outputAsLabel()  
  }
```

Result:

classDiagram
  Person <|-- Student
  Person <|-- Professor
  Person : +String name
  Person : +String phoneNumber
  Person : +String emailAddress
  Person: +purchaseParkingPass()
  Address "1" <-- "0..1" Person:lives at
  class Student{
    +int studentNumber
    +int averageMark
    +isEligibleToEnrol()
    +getSeminarsTaken()
  }
  class Professor{
    +int salary
  }
  class Address{
    +String street
    +String city
    +String state
    +int postalCode
    +String country
    -validate()
    +outputAsLabel()  
  }

Using entity-relationship diagrams¶

An entity-relationship diagram is composed of entity types and specifies relationships that exist between entities. It describes inter-related things in a specific domain of knowledge.

Example:

``` mermaid
erDiagram
  CUSTOMER ||--o{ ORDER : places
  ORDER ||--|{ LINE-ITEM : contains
  CUSTOMER }|..|{ DELIVERY-ADDRESS : uses
```

Result:

erDiagram
  CUSTOMER ||--o{ ORDER : places
  ORDER ||--|{ LINE-ITEM : contains
  CUSTOMER }|..|{ DELIVERY-ADDRESS : uses