Presentation

Presentation hints let the backend suggest a visualization without specifying pixels.

Purpose

Backend says "this is a gauge", not "fontSize: 28, padding: 12". The runtime owns layout.

UI inference (automatic)

Property semantics	Inferred component
number	Metric
number + min/max	Gauge
number + history	Trend
boolean read-only	Status
boolean writable	Switch
enum writable	Select
string	Text
location	Map

Presentation hints (explicit)

Number(view="slider")
Number(view="progress")
Boolean(view="alarm")
Enum(view="badge")
String(view="image" | "table" | "log")

All 16 supported views

Category	Views
READ	metric, gauge, trend, status, text, progress, alarm, badge, image, table, log, map
WRITE	switch, select, slider, input
ACTION	action button (stateless — not a property view)

Rules

• view overrides inference
• Hints are preferences, not contracts — the UI may adapt
• icon on Page/Action is a semantic token (chart, gauge, temperature), not a renderer icon name

Anti-pattern (what NOT to do)

{ "fontSize": 28, "padding": 12, "x": 100, "width": 240 }

This is pixel specification — forbidden. The runtime owns layout.

Also avoid renderer leakage: gap: 4px (use density: "compact") and icon: "bar-chart-outline" (use icon: "chart").

Common mistakes

• Using view="gauge" on a property without min/max → gauge still works with defaults
• Confusing view with user config — view is backend default, user can override locally
• Sending pixel/icon-library values instead of semantic tokens