UML

V1 supports a strict xaligo UML profile for class, component, activity, state-machine, and sequence diagrams. Use this page as the authoring overview; see the UML examples for rendered sample sources.

Minimal shape

<uml> is a semantic component inside a frame. It contains exactly one diagram-kind child such as <class-diagram> or <sequence-diagram>.

<frame id="sequence" title="Checkout Sequence" version="2026.07" margin-top="48">
  <metadata align="right" width="156" key-width="56" font-size="12" />
  <uml id="checkout-sequence">
    <sequence-diagram>
      <participant id="customer" title="Customer" />
      <lifeline id="api" title="Ordering API" />
      <message src="customer" dst="api" order="1" title="checkout(cart)" />
      <return-message src="api" dst="customer" order="2" title="ok" />
    </sequence-diagram>
  </uml>
</frame>

The <uml> container does not render its own border or title. Put visible titles, versions, owners, and review state in the owning frame metadata.

Authoring rules

• Element IDs are frame-local connection references; UML relations use those local IDs directly.
• Exactly one diagram family is allowed inside each <uml> component.
• Every diagram family has a closed element/relation vocabulary.
• Relation endpoints must reference existing local UML element IDs.
• direction="right|down" selects layout direction; sequence diagrams default to horizontal.
• Component diagrams may use component, interface, port, and artifact elements with dependency, realization, association, assembly, and delegation relations.
• Component boxes automatically grow with their interface rows and incoming association fan-out. Set component-width="280" or component-height="180" on <component-diagram> for diagram defaults, and override one box with <component width="340" height="220">. Omitting both height attributes keeps compact automatic height enabled.
• Set interface-width="88" on a <component> to use that width for every interface-name box inside the component. Interface descriptions continue to use the remaining horizontal space.
• Activity diagrams may group elements in <partition id="..." title="..."> swimlanes and set lanes="vertical|horizontal" with theme="xaligo".
• Sequence messages require unique positive dot-separated order values such as 1, 2, and 1.1.
• Non-participant sequence sources must already be active before sending a message or return.

Where to go next

• UML Examples: compact visual gallery and sample index.
• Structured diagram design: product and implementation direction for tables, databases, and UML.