UI.OrbitCenter
luastra/uiUI.OrbitCenter(input: Input): Node
Creates the non-interactive identity at the center of a constellation from a required title and optional description. The host preserves it in both spatial and list presentations.
Mental model
This is a declarative node: app.render describes it again from current state, while the host matches its stable id to the existing view.
Before you use it
Add luastra/ui to this module's dependencies in luastra.json, then import it with require("luastra/ui"). The project must declare the ui.render capability. app.render must return one UI.Screen root; place this node inside that tree rather than invoking it for a hidden side effect.
How it fits
The constructor validates its fields immediately and returns a UI.Node. After app.render returns, the host reconciles that node by stable id with the current semantic DOM-based interface. Current desktop and mobile hosts package the same web artifact; native adapters are used at capability boundaries.
When to use it
Use UI.OrbitCenter exactly once in each UI.Constellation to name the current semantic space. Do not use it as an action or encode application coordinates in its content.
Shared parameter groups
Parameters
| Parameter | Type / values | Description |
|---|---|---|
| id | lowercase path, required | Unique center ID. |
| title | string 1…160 bytes, required | Current constellation identity. |
| description | string ≤ 320 bytes? | Optional supporting summary. |
| padding | none | xs | sm | md | lg | xl | responsive | All-side inner spacing; responsive is supported only by padding. Group: Layout and surfaces. |
| margin | none | xs | sm | md | lg | xl | All-side outer spacing. Group: Layout and surfaces. |
| paddingX / paddingY | none | xs | sm | md | lg | xl | Axis-specific inner spacing. Group: Layout and surfaces. |
| paddingTop / paddingBottom / paddingStart / paddingEnd | none | xs | sm | md | lg | xl | Logical side-specific inner spacing. Group: Layout and surfaces. |
| marginX / marginY | none | xs | sm | md | lg | xl | Axis-specific outer spacing. Group: Layout and surfaces. |
| marginTop / marginBottom / marginStart / marginEnd | none | xs | sm | md | lg | xl | Logical side-specific outer spacing. Group: Layout and surfaces. |
| surface | plain | card | elevated | accent | Background, border, and elevation. Group: Layout and surfaces. |
| width | full | content | wide | Available width, 720 px maximum, or 1180 px maximum. Group: Layout and surfaces. |
| className | safe string ≤ 256 bytes | Additional admitted class tokens. Group: Layout and surfaces. |
| hidden | boolean | Visibility state. Group: State and semantics. |
Children and layout
This component does not accept arbitrary child nodes; named parameters provide its content.
Accessibility and keyboard
A stable id, logical render-tree order, and visible labels preserve predictable keyboard and screen-reader navigation.
Common mistakes
- Using a duplicate id or an uppercase path segment.
- Passing a shared-group parameter that is not listed on this component page.
Returns
Node — a validated declarative UI node that becomes part of the next host-neutral render tree.
What happens next
A validated declarative node appears after it is returned as part of the current render tree.
Failures and fixes
Invalid fields, duplicate IDs, unsupported child combinations, or a missing ui.render capability fail during check, render-tree validation, or host startup.
Availability
Experimental Constellation Orbit API in 0.5.0-alpha. Verify it against the selected SDK before depending on its shape.
Focused example
UI.OrbitCenter {
id = "map/root/center",
title = "My app",
description = "Choose a direction.",
}Continue with a complete recipe
This checked recipe uses UI.OrbitCenter inside complete authored files with the required manifest, test, and run steps.
Open build a small Constellation Orbit recipe