UISurface

Defined in: ui/src/UISurface.ts:38

Mounts a UI tree on an entity: entity.add(new UISurface({...})). Owns the tree’s root UIPanel element (exposed as root) and provides builder methods (.text(), .button(), .panel()) for constructing it. Layout is driven by UILayoutSystem each frame.

Extends

• Component

Constructors

Constructor

new UISurface(opts?): UISurface

Defined in: ui/src/UISurface.ts:53

Parameters

opts?

UISurfaceOptions

Returns

UISurface

Overrides

Component.constructor

Properties

_anchor

readonly _anchor: Anchor | undefined

Defined in: ui/src/UISurface.ts:46

Internal

---

_layer

readonly _layer: string | undefined

Defined in: ui/src/UISurface.ts:48

Internal

---

_offset

readonly _offset: object

Defined in: ui/src/UISurface.ts:47

Internal

x

x: number

y

y: number

---

_positioning

readonly _positioning: "anchor" | "transform"

Defined in: ui/src/UISurface.ts:49

Internal

---

entity

entity: Entity

Defined in: core/dist/index.d.ts:4116

Back-reference to the owning entity. Set by the engine when the component is added to an entity. Do not set manually.

Inherited from

Component.entity

---

root

readonly root: UIPanel

Defined in: ui/src/UISurface.ts:45

Root element of the mounted UI tree — a UIPanel created with this component and destroyed by it in onDestroy. Same instance for the component’s whole lifetime; after onDestroy it is destroyed (its destroy() is idempotent) and must not be re-added elsewhere.

---

inspectExclude?

static optional inspectExclude?: readonly string[]

Defined in: core/dist/index.d.ts:4338

Own fields and getters the Inspector leaves out of this component’s reflected state. Use it for bulk data that is not worth a diagnostic copy — a parsed tilemap, a large lookup table. Lists merge down the class chain, so a subclass adds to its base class’s exclusions.

class TilemapComponent extends VisualComponent {
  static inspectExclude = ["data"];
}

Inherited from

Component.inspectExclude

---

updatePriority?

static optional updatePriority?: number

Defined in: core/dist/index.d.ts:4325

Class-level default for updatePriority: every instance runs at this priority unless its own updatePriority is written. Undeclared = 0. Subclasses inherit their base class’s value unless they declare their own. Declare it on a component whose behavior depends on running after (or before) a sibling, so the entity that adds it does not have to control the add order.

class BoundsClamp extends Component {
  static updatePriority = 10; // after the follow that moves the camera
}

Inherited from

Component.updatePriority

Accessors

container

Get Signature

get container(): DisplayContainer

Defined in: ui/src/UISurface.ts:92

The PixiJS Container of the root panel.

Returns

DisplayContainer

---

context

Get Signature

get context(): EngineContext

Defined in: core/dist/index.d.ts:4171

Access the EngineContext from the entity’s scene. Throws if the entity is not in a scene.

Returns

EngineContext

Inherited from

Component.context

---

effectiveEnabled

Get Signature

get effectiveEnabled(): boolean

Defined in: core/dist/index.d.ts:4141

Whether the component is actually running: enabled, on an active entity, and past onAdd. This is the state onEnable and onDisable track — read it when a method has to behave one way live and another way dormant.

Returns

boolean

Inherited from

Component.effectiveEnabled

---

enabled

Get Signature

get enabled(): boolean

Defined in: core/dist/index.d.ts:4133

Whether this component runs. Disabled components are skipped by ComponentUpdateSystem.

Writing this fires onEnable / onDisable when the effective state changes — enabled && entity.isActive. A component disabled here stays disabled through a setActive(false) / setActive(true) cycle on its entity.

Returns

boolean

Set Signature

set enabled(value): void

Defined in: core/dist/index.d.ts:4134

Parameters

value

boolean

Returns

void

Inherited from

Component.enabled

---

focusScope

Get Signature

get focusScope(): UIFocusScope | null

Defined in: ui/src/UISurface.ts:101

The scope UISurfaceOptions.focus asks for, or null when the surface carries none. It is the root panel’s scope: surface.root.focusScope is the same object.

Returns

UIFocusScope | null

---

offset

Get Signature

get offset(): Readonly<{ x: number; y: number; }>

Defined in: ui/src/UISurface.ts:87

The offset the tree is drawn at.

Returns

Readonly<{ x: number; y: number; }>

---

scene

Get Signature

get scene(): Scene

Defined in: core/dist/index.d.ts:4166

Access the entity’s scene. Throws if the entity is not in a scene. Prefer this over threading through this.entity.scene in component code.

Returns

Scene

Inherited from

Component.scene

---

updatePriority

Get Signature

get updatePriority(): number

Defined in: core/dist/index.d.ts:4159

Where this component runs among its siblings. ComponentUpdateSystem calls update / fixedUpdate on an entity’s components in ascending priority; equal priorities run in add order. Undeclared = 0, so a negative value runs before siblings that keep the default and a positive value runs after them. Writable at any time, before or after add(). Defaults to the class’s static updatePriority.

class Player extends Entity {
  setup() {
    this.add(new Mover());
    this.add(new Brain()).updatePriority = -1; // decides before Mover moves
  }
}

Returns

number

Set Signature

set updatePriority(value): void

Defined in: core/dist/index.d.ts:4160

Parameters

value

number

Returns

void

Inherited from

Component.updatePriority

---

visible

Get Signature

get visible(): boolean

Defined in: ui/src/UISurface.ts:169

Whether the mounted UI tree is visible. Reads back what you set, even while the entity is dormant and the tree is hidden.

Returns

boolean

Set Signature

set visible(v): void

Defined in: ui/src/UISurface.ts:173

Parameters

v

boolean

Returns

void

Methods

_applyEnabled()

_applyEnabled(effective): void

Defined in: core/dist/index.d.ts:4273

Internal

Force an effective-enabled transition, firing the hook on a flip. Used by Entity for teardown, where enabled and the entity’s activeness both still read true.

Parameters

effective

boolean

Returns

void

Inherited from

Component._applyEnabled

---

_isTornDown()

_isTornDown(): boolean

Defined in: core/dist/index.d.ts:4254

Internal

Internal: true once this component has been removed or its entity destroyed. Components are terminal — Entity.add uses this to reject re-attaching an instance whose cleanups and onDestroy already ran.

Returns

boolean

Inherited from

Component._isTornDown

---

_markTornDown()

_markTornDown(): void

Defined in: core/dist/index.d.ts:4260

Internal

Internal: mark this component torn down. Called by Entity.remove() and Entity._performDestroy() after onDestroy runs.

Returns

void

Inherited from

Component._markTornDown

---

_refreshEnabled()

_refreshEnabled(): void

Defined in: core/dist/index.d.ts:4266

Internal

Recompute effective enabled-ness from enabled and the entity’s activeness, firing the hook on a flip.

Returns

void

Inherited from

Component._refreshEnabled

---

_runCleanups()

_runCleanups(onError?): void

Defined in: core/dist/index.d.ts:4241

Internal

Run and clear all registered cleanups. Called by Entity.remove() and Entity._performDestroy() before onDestroy.

Parameters

onError?

(error) => void

Returns

void

Inherited from

Component._runCleanups

---

addCleanup()

protected addCleanup(fn): void

Defined in: core/dist/index.d.ts:4229

Register a cleanup function to run when this component is removed or destroyed, before onDestroy. Use it for what listen, listenScene and listenBus do not cover, such as an unsubscribe from a custom emitter.

Parameters

fn

() => void

Returns

void

Inherited from

Component.addCleanup

---

addElement()

addElement(child): void

Defined in: ui/src/UISurface.ts:148

Append an arbitrary UIElement (e.g. UIImage, UIProgressBar, UICheckbox) as the last child. Prefer the .text(), .button(), and .panel() builders for those element types — they’re shorter.

Parameters

child

UIElement

Returns

void

---

button()

button(label, opts): UIButton

Defined in: ui/src/UISurface.ts:129

Add a button element.

Parameters

label

string

opts

Omit<UIButtonProps, "children">

Returns

UIButton

---

destroy()

destroy(): void

Defined in: core/dist/index.d.ts:4247

End this component’s life on its own — the same as entity.remove(SomeClass), without having to name its own class from inside itself, which breaks under subclassing.

Returns

void

Inherited from

Component.destroy

---

fixedUpdate()?

optional fixedUpdate(dt): void

Defined in: core/dist/index.d.ts:4310

Called every fixed timestep by the built-in ComponentUpdateSystem.

Parameters

dt

number

Fixed timestep in seconds, scaled by scene and entity timeScale.

Returns

void

Inherited from

Component.fixedUpdate

---

insertElementBefore()

insertElementBefore(child, before): void

Defined in: ui/src/UISurface.ts:161

Insert child immediately before before in the root panel’s child list. Falls back to append if before isn’t a current child.

Parameters

child

UIElement

before

UIElement

Returns

void

---

listen()

protected listen<T>(source, token, handler): void

Defined in: core/dist/index.d.ts:4211

Subscribe to events from an entity or a state machine, auto-unsubscribe on removal.

this.listen(this.entity, Hurt, ({ dir }) => this.knockback(dir));
this.listen(brain.mode, brain.mode.events.entered, ({ state }) =>
  this.anim.play(state),
);

Type Parameters

T

T

Parameters

source

EventSource

token

EventToken<T>

handler

(data) => void

Returns

void

Inherited from

Component.listen

---

listenBus()

protected listenBus<K>(event, handler): void

Defined in: core/dist/index.d.ts:4222

Subscribe to an engine EventBus event, auto-unsubscribe on removal. Throws when the entity is not in a scene, like listenScene.

Type Parameters

K

K extends keyof EngineEvents

Parameters

event

K

handler

(data) => void

Returns

void

Inherited from

Component.listenBus

---

listenScene()

protected listenScene<T>(token, handler): void

Defined in: core/dist/index.d.ts:4217

Subscribe to scene-level events, auto-unsubscribe on removal. Handlers fire for bubbled entity events (entity = source) and scene.emit events (entity = undefined).

Type Parameters

T

T

Parameters

token

EventToken<T>

handler

(data, entity?) => void

Returns

void

Inherited from

Component.listenScene

---

onAdd()

onAdd(): void

Defined in: ui/src/UISurface.ts:186

Called when the component is added to an entity. Validate dependencies here — a service, a sibling component, a render layer — and throw when one is missing. The throw is attributed to this component, recorded in Inspector.getErrors().callbackErrors, and rethrown, so it reaches the caller of entity.add() unchanged.

Returns

void

Overrides

Component.onAdd

---

onDestroy()

onDestroy(): void

Defined in: ui/src/UISurface.ts:231

Called when the component is destroyed (entity destroyed or component removed).

Returns

void

Overrides

Component.onDestroy

---

onDisable()

onDisable(): void

Defined in: ui/src/UISurface.ts:182

Called when the component stops being effectively enabled — enabled went false, the entity (or an ancestor) was deactivated, or the component is being removed or destroyed. Put live resources to sleep here; the component is reused afterwards, so do not free anything onEnable cannot rebuild.

Returns

void

Overrides

Component.onDisable

---

onEnable()

onEnable(): void

Defined in: ui/src/UISurface.ts:178

Called when the component becomes effectively enabled — enabled is true and the entity is active. Fires right after onAdd() for a component added to an active entity, and again on every later flip. Bring live resources back online here (unpause a sound, show a display object, re-enable a physics body). Game-state reset does not belong here: the hook sees whatever state the component held while dormant.

Returns

void

Overrides

Component.onEnable

---

panel()

panel(opts?): UIPanel

Defined in: ui/src/UISurface.ts:134

Add a nested child panel.

Parameters

opts?

UIPanelProps

Returns

UIPanel

---

removeElement()

removeElement(child): void

Defined in: ui/src/UISurface.ts:153

Remove a previously added element. No-op if the element isn’t a child.

Parameters

child

UIElement

Returns

void

---

scrollView()

scrollView(opts?): UIScrollView

Defined in: ui/src/UISurface.ts:139

Add a nested scrollable viewport.

Parameters

opts?

UIScrollViewProps

Returns

UIScrollView

---

service()

protected service<T>(key): T

Defined in: core/dist/index.d.ts:4188

Lazy proxy-based service resolution. Can be used at field-declaration time:

readonly input = this.service(InputManagerKey);

The actual resolution is deferred until first property access.

Type Parameters

T

T extends object

Parameters

key

ServiceKey<T>

Returns

T

Inherited from

Component.service

---

setOffset()

setOffset(x, y): void

Defined in: ui/src/UISurface.ts:79

Move the whole tree by a screen-space offset, on top of whatever its anchor or transform positioning resolves to. Animating a sliding panel is a setOffset per frame.

Parameters

x

number

y

number

Returns

void

---

setPointerHandlers()

setPointerHandlers(handlers): void

Defined in: ui/src/UISurface.ts:115

Set the root panel’s pointer / hover handlers (onHover, onPointerOver, onPointerOut) after construction — forwarded to root. (update() can’t double as the prop setter here: on a Component it’s the per-frame lifecycle hook the engine calls.) Like the element update, a present key replaces that handler and an absent key leaves it intact, so a partial setPointerHandlers({ onHover }) won’t drop the others. Handy for wiring attachTooltip: surface.setPointerHandlers({ onHover: tip.setActive }).

Parameters

handlers

PointerEventProps

Returns

void

---

sibling()

protected sibling<C>(cls): C

Defined in: core/dist/index.d.ts:4199

Lazy proxy-based sibling component resolution. Can be used at field-declaration time:

readonly anim = this.sibling(AnimatedSpriteComponent);

The actual resolution is deferred until first property access. The reference passes instanceof cls before it resolves, so an engine API that checks the type of what it is handed (camera.follow(this.transform)) accepts it.

Type Parameters

C

C extends Component

Parameters

cls

ComponentClass<C>

Returns

C

Inherited from

Component.sibling

---

stateMachine()

protected stateMachine<S>(states, initial, options?): StateMachine<S>

Defined in: core/dist/index.d.ts:4235

Create a state machine whose hooks and event handlers are attributed to this component when they throw. The machine can be declared as a field because service lookup waits until a hook runs.

Type Parameters

S

S extends string

Parameters

states

StateDefinitions<S>

initial

NoInfer<S>

options?

StateMachineOptions

Returns

StateMachine<S>

Inherited from

Component.stateMachine

---

text()

text(content, style?, opts?): UIText

Defined in: ui/src/UISurface.ts:120

Add a text element. See UIPanel.text for opts.

Parameters

content

string

style?

Partial<TextStyleOptions>

opts?

UITextBuilderProps

Returns

UIText

---

update()?

optional update(dt): void

Defined in: core/dist/index.d.ts:4305

Called every frame by the built-in ComponentUpdateSystem.

Parameters

dt

number

Frame delta in seconds, scaled by scene and entity timeScale.

Returns

void

Inherited from

Component.update

---

use()

protected use<T>(key): T

Defined in: core/dist/index.d.ts:4179

Resolve a service by key, cached after first lookup. Scene-scoped values (registered via scene._registerScoped) take precedence over engine scope. A key declared with scope: "scene" that falls back to engine scope emits a one-shot dev warning — almost always signals a missed beforeEnter hook.

Type Parameters

T

T

Parameters

key

ServiceKey<T>

Returns

T

Inherited from

Component.use