Layer

Abstract base class for everything that can be added to a viewport.

A Layer owns a set of renderable objects and contributes them to the scene each frame. Subclasses (e.g. ImageLayer, VolumeLayer, LabelLayer) implement Layer.update to build or refresh those objects for the current view, and may override the attach/detach hooks to acquire and release resources when the layer joins or leaves a viewport.

Layers carry shared presentation state — Layer.opacity and blend mode — and expose a lifecycle LayerState (initialized → loading → ready) that observers can subscribe to. A layer instance may be attached to only one viewport at a time.

Extended by

• AxesLayer
• ImageLayer
• VolumeLayer
• LabelLayer

Constructor

new Layer(__namedParameters?): Layer;

Parameter	Type
__namedParameters	LayerProps

Types

LayerState

type LayerState = "initialized" | "loading" | "ready";

Properties

type

abstract readonly type: string;

blendMode

blendMode: BlendMode;

Accessors

opacity number

get opacity(): number;

set opacity(value): void;

Parameter	Type
value	number

coverageGroups ReadonlyMap<number | null, readonly RenderableObject[]>

get coverageGroups(): ReadonlyMap<number | null, readonly RenderableObject[]>;

state LayerState

get state(): LayerState;

Methods

update() void

abstract update(viewport?): void;

Parameter	Type
viewport?	Viewport

onEvent() void

onEvent(_): void;

Parameter	Type
_	EventContext

onAttached() void

onAttached(context): void;

Parameter	Type
context	IdetikContext

onDetached() void

onDetached(context): void;

Parameter	Type
context	IdetikContext

attach() void

protected attach(_context): void;

Parameter	Type
_context	IdetikContext

detach() void

protected detach(_context): void;

Parameter	Type
_context	IdetikContext

addStateChangeCallback() void

addStateChangeCallback(callback): void;

Parameter	Type
callback	StateChangeCallback

removeStateChangeCallback() void

removeStateChangeCallback(callback): void;

Parameter	Type
callback	StateChangeCallback

setState() void

protected setState(newState): void;

Parameter	Type
newState	LayerState

addObject() void

protected addObject(object, coverageGroup?): void;

Parameter	Type	Default value
object	RenderableObject	undefined
coverageGroup	number | null	null

clearObjects() void

protected clearObjects(): void;

getUniforms() Record<string, unknown>

Get uniforms for shader program. Override in derived classes that need custom uniforms.

getUniforms(): Record<string, unknown>;