Documentation / @ripl/canvas / CanvasContext

Class: CanvasContext

Defined in: canvas/src/context.ts:115

Canvas 2D rendering context implementation, mapping the unified API to CanvasRenderingContext2D.

Extends

• DOMContext<HTMLCanvasElement>

Constructors

Constructor

new CanvasContext(target, options?): CanvasContext

Defined in: canvas/src/context.ts:318

Parameters

Parameter	Type
target	string | HTMLElement
options?	ContextOptions<Record<string, unknown>>

Returns

CanvasContext

Overrides

DOMContext.constructor

Properties

Property	Modifier	Type	Default value	Description	Inherited from	Defined in
buffer	public	boolean	false	Whether drawing is buffered rather than committed to the surface immediately.	DOMContext.buffer	core/src/context/context.ts:121
context	protected	CanvasRenderingContext2D	undefined	-	-	canvas/src/context.ts:117
currentState	protected	BaseState	undefined	-	DOMContext.currentState	core/src/context/context.ts:144
element	readonly	HTMLCanvasElement	undefined	The underlying DOM element the context renders into.	DOMContext.element	core/src/context/context.ts:116
height	public	number	undefined	Current height, in pixels, of the rendering surface.	DOMContext.height	core/src/context/context.ts:131
hitTestHonoursTransform	public	boolean	false	Whether this context's hit testing natively accounts for element and ancestor group transforms (as SVG does, via the DOM). When false (e.g. canvas), callers map the hit point into the element's local space before testing. See getWorldTransform.	DOMContext.hitTestHonoursTransform	core/src/context/context.ts:127
meta	readonly	TMeta	undefined	Arbitrary metadata attached to the context.	DOMContext.meta	core/src/context/context.ts:118
parent?	public	EventBus<ContextEventMap>	undefined	The parent event bus that emitted events bubble up to, if any.	DOMContext.parent	core/src/core/event-bus.ts:89
renderDepth	protected	number	0	-	DOMContext.renderDepth	core/src/context/context.ts:145
renderedElements	public	RenderElement[]	undefined	Elements rendered during the current pass, used for hit testing.	DOMContext.renderedElements	core/src/context/context.ts:141
renderElement?	public	RenderElement	undefined	The element currently being rendered, if any.	DOMContext.renderElement	core/src/context/context.ts:139
root	readonly	HTMLElement	undefined	The host DOM element that the context's rendering surface is mounted into.	DOMContext.root	dom/src/context.ts:45
saveDepth	protected	number	0	-	DOMContext.saveDepth	core/src/context/context.ts:146
scaleDPR	public	Scale<number, number>	undefined	Scale mapping logical pixels to device pixels using the device pixel ratio.	DOMContext.scaleDPR	core/src/context/context.ts:137
scaleX	public	Scale<number, number>	undefined	Scale mapping domain x coordinates to surface x coordinates.	DOMContext.scaleX	core/src/context/context.ts:133
scaleY	public	Scale<number, number>	undefined	Scale mapping domain y coordinates to surface y coordinates.	DOMContext.scaleY	core/src/context/context.ts:135
states	protected	BaseState[]	undefined	-	DOMContext.states	core/src/context/context.ts:143
type	readonly	string	undefined	The context type identifier (e.g. canvas, svg).	DOMContext.type	core/src/context/context.ts:114
width	public	number	undefined	Current width, in pixels, of the rendering surface.	DOMContext.width	core/src/context/context.ts:129
defaultKey	readonly	typeof defaultKey	undefined	The key under which resources are retained when no explicit key is provided.	DOMContext.defaultKey	core/src/core/disposer.ts:11

Accessors

currentRenderElement

Get Signature

get currentRenderElement(): RenderElement | undefined

Defined in: core/src/context/context.ts:150

The element currently being rendered; setting a non-abstract element also records it in Context.renderedElements.

Returns

RenderElement | undefined

Set Signature

set currentRenderElement(element): void

Defined in: core/src/context/context.ts:154

Parameters

Parameter	Type
element	RenderElement | undefined

Returns

void

Inherited from

DOMContext.currentRenderElement

---

direction

Get Signature

get direction(): Direction

Defined in: canvas/src/context.ts:149

The current text direction.

Returns

Direction

Set Signature

set direction(value): void

Defined in: canvas/src/context.ts:153

Directionality used when rendering text.

Parameters

Parameter	Type
value	Direction

Returns

void

Directionality used when rendering text.

Overrides

DOMContext.direction

---

fill

Get Signature

get fill(): string

Defined in: canvas/src/context.ts:122

The current fill style — a colour or CSS gradient string.

Returns

string

Set Signature

set fill(value): void

Defined in: canvas/src/context.ts:126

Fill style (CSS colour, gradient, or pattern) used to paint filled regions.

Parameters

Parameter	Type
value	string

Returns

void

Fill style (CSS colour, gradient, or pattern) used to paint filled regions.

Overrides

DOMContext.fill

---

filter

Get Signature

get filter(): string

Defined in: canvas/src/context.ts:140

The current filter applied to drawing operations.

Returns

string

Set Signature

set filter(value): void

Defined in: canvas/src/context.ts:144

CSS filter string applied to subsequent drawing operations (e.g. blur(4px)).

Parameters

Parameter	Type
value	string

Returns

void

CSS filter string applied to subsequent drawing operations (e.g. blur(4px)).

Overrides

DOMContext.filter

---

font

Get Signature

get font(): string

Defined in: canvas/src/context.ts:158

The current font used for text rendering.

Returns

string

Set Signature

set font(value): void

Defined in: canvas/src/context.ts:162

CSS font shorthand used when rendering text.

Parameters

Parameter	Type
value	string

Returns

void

CSS font shorthand used when rendering text.

Overrides

DOMContext.font

---

fontKerning

Get Signature

get fontKerning(): FontKerning

Defined in: canvas/src/context.ts:167

The current font kerning mode.

Returns

FontKerning

Set Signature

set fontKerning(value): void

Defined in: canvas/src/context.ts:171

Whether font kerning is applied when rendering text.

Parameters

Parameter	Type
value	FontKerning

Returns

void

Whether font kerning is applied when rendering text.

Overrides

DOMContext.fontKerning

---

globalCompositeOperation

Get Signature

get globalCompositeOperation(): unknown

Defined in: canvas/src/context.ts:185

The current compositing operation used when drawing.

Returns

unknown

Set Signature

set globalCompositeOperation(value): void

Defined in: canvas/src/context.ts:189

Compositing operation controlling how new drawing is blended with existing content.

Parameters

Parameter	Type
value	unknown

Returns

void

Compositing operation controlling how new drawing is blended with existing content.

Overrides

DOMContext.globalCompositeOperation

---

lineCap

Get Signature

get lineCap(): LineCap

Defined in: canvas/src/context.ts:194

The current line cap style for stroke endpoints.

Returns

LineCap

Set Signature

set lineCap(value): void

Defined in: canvas/src/context.ts:198

Cap style drawn at the endpoints of stroked lines.

Parameters

Parameter	Type
value	LineCap

Returns

void

Cap style drawn at the endpoints of stroked lines.

Overrides

DOMContext.lineCap

---

lineDash

Get Signature

get lineDash(): number[]

Defined in: canvas/src/context.ts:203

The current line dash pattern.

Returns

number[]

Set Signature

set lineDash(value): void

Defined in: canvas/src/context.ts:207

Dash pattern as alternating stroke and gap lengths; empty for a solid line.

Parameters

Parameter	Type
value	number[]

Returns

void

Dash pattern as alternating stroke and gap lengths; empty for a solid line.

Overrides

DOMContext.lineDash

---

lineDashOffset

Get Signature

get lineDashOffset(): number

Defined in: canvas/src/context.ts:212

The current offset into the line dash pattern.

Returns

number

Set Signature

set lineDashOffset(value): void

Defined in: canvas/src/context.ts:216

Distance into the line dash pattern at which dashing begins.

Parameters

Parameter	Type
value	number

Returns

void

Distance into the line dash pattern at which dashing begins.

Overrides

DOMContext.lineDashOffset

---

lineJoin

Get Signature

get lineJoin(): LineJoin

Defined in: canvas/src/context.ts:221

The current line join style for stroke corners.

Returns

LineJoin

Set Signature

set lineJoin(value): void

Defined in: canvas/src/context.ts:225

Join style drawn where two stroked segments meet.

Parameters

Parameter	Type
value	LineJoin

Returns

void

Join style drawn where two stroked segments meet.

Overrides

DOMContext.lineJoin

---

lineWidth

Get Signature

get lineWidth(): number

Defined in: canvas/src/context.ts:230

The current stroke width, in pixels.

Returns

number

Set Signature

set lineWidth(value): void

Defined in: canvas/src/context.ts:234

Width, in pixels, of stroked lines.

Parameters

Parameter	Type
value	number

Returns

void

Width, in pixels, of stroked lines.

Overrides

DOMContext.lineWidth

---

miterLimit

Get Signature

get miterLimit(): number

Defined in: canvas/src/context.ts:239

The current miter limit for stroke joins.

Returns

number

Set Signature

set miterLimit(value): void

Defined in: canvas/src/context.ts:243

Miter length limit ratio applied to miter line joins.

Parameters

Parameter	Type
value	number

Returns

void

Miter length limit ratio applied to miter line joins.

Overrides

DOMContext.miterLimit

---

opacity

Get Signature

get opacity(): number

Defined in: canvas/src/context.ts:176

The current global opacity applied to drawing operations.

Returns

number

Set Signature

set opacity(value): void

Defined in: canvas/src/context.ts:180

Global alpha applied to everything drawn, from 0 to 1.

Parameters

Parameter	Type
value	number

Returns

void

Global alpha applied to everything drawn, from 0 to 1.

Overrides

DOMContext.opacity

---

rotation

Get Signature

get rotation(): Rotation

Defined in: core/src/context/context.ts:388

Rotation applied to the element's transform, as radians or a deg/rad string.

Returns

Rotation

Set Signature

set rotation(value): void

Defined in: core/src/context/context.ts:392

Rotation applied to the element's transform, as radians or a deg/rad string.

Parameters

Parameter	Type
value	Rotation

Returns

void

Rotation applied to the element's transform, as radians or a deg/rad string.

Inherited from

DOMContext.rotation

---

shadowBlur

Get Signature

get shadowBlur(): number

Defined in: canvas/src/context.ts:248

The current shadow blur radius.

Returns

number

Set Signature

set shadowBlur(value): void

Defined in: canvas/src/context.ts:252

Gaussian blur radius applied to drawn shadows.

Parameters

Parameter	Type
value	number

Returns

void

Gaussian blur radius applied to drawn shadows.

Overrides

DOMContext.shadowBlur

---

shadowColor

Get Signature

get shadowColor(): string

Defined in: canvas/src/context.ts:257

The current shadow colour.

Returns

string

Set Signature

set shadowColor(value): void

Defined in: canvas/src/context.ts:261

Colour of drawn shadows.

Parameters

Parameter	Type
value	string

Returns

void

Colour of drawn shadows.

Overrides

DOMContext.shadowColor

---

shadowOffsetX

Get Signature

get shadowOffsetX(): number

Defined in: canvas/src/context.ts:266

The current horizontal shadow offset.

Returns

number

Set Signature

set shadowOffsetX(value): void

Defined in: canvas/src/context.ts:270

Horizontal offset, in pixels, of drawn shadows.

Parameters

Parameter	Type
value	number

Returns

void

Horizontal offset, in pixels, of drawn shadows.

Overrides

DOMContext.shadowOffsetX

---

shadowOffsetY

Get Signature

get shadowOffsetY(): number

Defined in: canvas/src/context.ts:275

The current vertical shadow offset.

Returns

number

Set Signature

set shadowOffsetY(value): void

Defined in: canvas/src/context.ts:279

Vertical offset, in pixels, of drawn shadows.

Parameters

Parameter	Type
value	number

Returns

void

Vertical offset, in pixels, of drawn shadows.

Overrides

DOMContext.shadowOffsetY

---

stroke

Get Signature

get stroke(): string

Defined in: canvas/src/context.ts:284

The current stroke style — a colour or CSS gradient string.

Returns

string

Set Signature

set stroke(value): void

Defined in: canvas/src/context.ts:288

Stroke style (CSS colour, gradient, or pattern) used to paint outlines.

Parameters

Parameter	Type
value	string

Returns

void

Stroke style (CSS colour, gradient, or pattern) used to paint outlines.

Overrides

DOMContext.stroke

---

textAlign

Get Signature

get textAlign(): TextAlignment

Defined in: canvas/src/context.ts:301

The current horizontal text alignment.

Returns

TextAlignment

Set Signature

set textAlign(value): void

Defined in: canvas/src/context.ts:305

Horizontal alignment of text relative to the drawing position.

Parameters

Parameter	Type
value	TextAlignment

Returns

void

Horizontal alignment of text relative to the drawing position.

Overrides

DOMContext.textAlign

---

textBaseline

Get Signature

get textBaseline(): TextBaseline

Defined in: canvas/src/context.ts:310

The current vertical text baseline.

Returns

TextBaseline

Set Signature

set textBaseline(value): void

Defined in: canvas/src/context.ts:314

Vertical baseline used when positioning text.

Parameters

Parameter	Type
value	TextBaseline

Returns

void

Vertical baseline used when positioning text.

Overrides

DOMContext.textBaseline

---

transformOriginX

Get Signature

get transformOriginX(): TransformOrigin

Defined in: core/src/context/context.ts:397

Horizontal origin about which rotation and scaling are applied.

Returns

TransformOrigin

Set Signature

set transformOriginX(value): void

Defined in: core/src/context/context.ts:401

Horizontal origin about which rotation and scaling are applied.

Parameters

Parameter	Type
value	TransformOrigin

Returns

void

Horizontal origin about which rotation and scaling are applied.

Inherited from

DOMContext.transformOriginX

---

transformOriginY

Get Signature

get transformOriginY(): TransformOrigin

Defined in: core/src/context/context.ts:406

Vertical origin about which rotation and scaling are applied.

Returns

TransformOrigin

Set Signature

set transformOriginY(value): void

Defined in: core/src/context/context.ts:410

Vertical origin about which rotation and scaling are applied.

Parameters

Parameter	Type
value	TransformOrigin

Returns

void

Vertical origin about which rotation and scaling are applied.

Inherited from

DOMContext.transformOriginY

---

transformScaleX

Get Signature

get transformScaleX(): number

Defined in: core/src/context/context.ts:370

Horizontal scale factor applied to the element's transform.

Returns

number

Set Signature

set transformScaleX(value): void

Defined in: core/src/context/context.ts:374

Horizontal scale factor applied to the element's transform.

Parameters

Parameter	Type
value	number

Returns

void

Horizontal scale factor applied to the element's transform.

Inherited from

DOMContext.transformScaleX

---

transformScaleY

Get Signature

get transformScaleY(): number

Defined in: core/src/context/context.ts:379

Vertical scale factor applied to the element's transform.

Returns

number

Set Signature

set transformScaleY(value): void

Defined in: core/src/context/context.ts:383

Vertical scale factor applied to the element's transform.

Parameters

Parameter	Type
value	number

Returns

void

Vertical scale factor applied to the element's transform.

Inherited from

DOMContext.transformScaleY

---

translateX

Get Signature

get translateX(): number

Defined in: core/src/context/context.ts:352

Horizontal translation, in pixels, applied to the element's transform.

Returns

number

Set Signature

set translateX(value): void

Defined in: core/src/context/context.ts:356

Horizontal translation, in pixels, applied to the element's transform.

Parameters

Parameter	Type
value	number

Returns

void

Horizontal translation, in pixels, applied to the element's transform.

Inherited from

DOMContext.translateX

---

translateY

Get Signature

get translateY(): number

Defined in: core/src/context/context.ts:361

Vertical translation, in pixels, applied to the element's transform.

Returns

number

Set Signature

set translateY(value): void

Defined in: core/src/context/context.ts:365

Vertical translation, in pixels, applied to the element's transform.

Parameters

Parameter	Type
value	number

Returns

void

Vertical translation, in pixels, applied to the element's transform.

Inherited from

DOMContext.translateY

---

zIndex

Get Signature

get zIndex(): number

Defined in: core/src/context/context.ts:343

Stacking order used to sort elements during rendering; higher values draw on top.

Returns

number

Set Signature

set zIndex(value): void

Defined in: core/src/context/context.ts:347

Stacking order used to sort elements during rendering; higher values draw on top.

Parameters

Parameter	Type
value	number

Returns

void

Stacking order used to sort elements during rendering; higher values draw on top.

Inherited from

DOMContext.zIndex

Methods

applyClip()

applyClip(path, fillRule?): void

Defined in: canvas/src/context.ts:413

Clips subsequent drawing operations to the given path.

Parameters

Parameter	Type
path	CanvasPath
fillRule?	FillRule

Returns

void

Overrides

DOMContext.applyClip

---

applyFill()

applyFill(element, fillRule?): void

Defined in: canvas/src/context.ts:423

Fills the given path or text element using the current fill style.

Parameters

Parameter	Type
element	ContextText | CanvasPath
fillRule?	FillRule

Returns

void

Overrides

DOMContext.applyFill

---

applyGroupPaint()

protected applyGroupPaint(group): void

Defined in: core/src/context/context.ts:558

Applies a group's own inherited paint (fill, stroke, font, line, shadow, text) to the context so descendants pick it up from the copied state. Transforms are applied separately and opacity is composited at the boundary, so both are skipped here.

Parameters

Parameter	Type
group	Element

Returns

void

Inherited from

DOMContext.applyGroupPaint

---

applyStroke()

applyStroke(element): void

Defined in: canvas/src/context.ts:428

Strokes the given path or text element using the current stroke style.

Parameters

Parameter	Type
element	ContextText | CanvasPath

Returns

void

Overrides

DOMContext.applyStroke

---

batch()

batch<TResult>(body): TResult

Defined in: core/src/context/context.ts:514

Clears the rendering surface and brackets the callback in markRenderStart/markRenderEnd, returning the callback's result.

Type Parameters

Type Parameter	Default type
TResult	void

Parameters

Parameter	Type
body	() => TResult

Returns

TResult

Inherited from

DOMContext.batch

---

clear()

clear(): void

Defined in: canvas/src/context.ts:366

Clears the entire canvas surface.

Returns

void

Overrides

DOMContext.clear

---

createPath()

createPath(id?): CanvasPath

Defined in: canvas/src/context.ts:408

Creates a new CanvasPath, optionally reusing an id for diffing efficiency.

Parameters

Parameter	Type
id?	string

Returns

CanvasPath

Overrides

DOMContext.createPath

---

createText()

createText(options): ContextText

Defined in: core/src/context/context.ts:640

Creates a new text element from the given options.

Parameters

Parameter	Type
options	TextOptions

Returns

ContextText

Inherited from

DOMContext.createText

---

destroy()

destroy(): void

Defined in: dom/src/context.ts:304

Destroys the context, removing the DOM element and disposing all resources.

Returns

void

Inherited from

DOMContext.destroy

---

disableInteraction()

disableInteraction(): void

Defined in: dom/src/context.ts:292

Disables DOM interaction events and clears the active element set.

Returns

void

Inherited from

DOMContext.disableInteraction

---

dispose()

protected dispose(key?): void

Defined in: core/src/core/disposer.ts:25

Disposes all resources under the given key, or all resources if no key is provided.

Parameters

Parameter	Type
key?	PropertyKey

Returns

void

Inherited from

DOMContext.dispose

---

drawImage()

drawImage(image, x, y, width?, height?): void

Defined in: canvas/src/context.ts:418

Draws an image onto the canvas at the given position and optional size.

Parameters

Parameter	Type
image	CanvasImageSource
x	number
y	number
width?	number
height?	number

Returns

void

Overrides

DOMContext.drawImage

---

emit()

Call Signature

emit<TEvent>(event): TEvent

Defined in: core/src/core/event-bus.ts:137

Emits an event, invoking all matching handlers and bubbling to the parent if applicable.

Type Parameters

Type Parameter	Default type
TEvent extends Event<undefined>	Event<undefined>

Parameters

Parameter	Type
event	TEvent

Returns

TEvent

Inherited from

DOMContext.emit

Call Signature

emit<TEvent>(type, data): Event<ContextEventMap[TEvent]>

Defined in: core/src/core/event-bus.ts:138

Emits an event, invoking all matching handlers and bubbling to the parent if applicable.

Type Parameters

Type Parameter
TEvent extends keyof ContextEventMap

Parameters

Parameter	Type
type	TEvent
data	ContextEventMap[TEvent]

Returns

Event<ContextEventMap[TEvent]>

Inherited from

DOMContext.emit

---

enableInteraction()

enableInteraction(): void

Defined in: dom/src/context.ts:264

Enables DOM interaction events (mouse enter, leave, move, click, drag) with element hit testing.

Returns

void

Inherited from

DOMContext.enableInteraction

---

export()

export(): ContextExport

Defined in: canvas/src/context.ts:443

Captures a snapshot of the canvas and returns format-specific exporters (see ContextExport).

Returns

ContextExport

Overrides

DOMContext.export

---

getDefaultState()

protected getDefaultState(): BaseState

Defined in: core/src/context/context.ts:444

Returns

BaseState

Inherited from

DOMContext.getDefaultState

---

has()

has(type): boolean

Defined in: core/src/core/event-bus.ts:94

Returns whether there are any listeners registered for the given event type.

Parameters

Parameter	Type
type	keyof ContextEventMap

Returns

boolean

Inherited from

DOMContext.has

---

hitTest()

protected hitTest(events, x, y): RenderElement[]

Defined in: core/src/context/context.ts:679

Tests which rendered elements intersect the given point for the given event types, returning them sorted by zIndex (highest first).

Parameters

Parameter	Type
events	string[]
x	number
y	number

Returns

RenderElement[]

Inherited from

DOMContext.hitTest

---

init()

protected init(): void

Defined in: dom/src/context.ts:81

Returns

void

Inherited from

DOMContext.init

---

invalidateTrackedElements()

invalidateTrackedElements(event?): void

Defined in: core/src/context/context.ts:491

Clears the cached list of tracked elements for interaction, forcing a rebuild on the next hit test.

Parameters

Parameter	Type
event?	string

Returns

void

Inherited from

DOMContext.invalidateTrackedElements

---

isPointInPath()

isPointInPath(path, x, y, fillRule?): boolean

Defined in: canvas/src/context.ts:433

Tests whether a point lies inside the filled region of a path.

Parameters

Parameter	Type
path	CanvasPath
x	number
y	number
fillRule?	FillRule

Returns

boolean

Overrides

DOMContext.isPointInPath

---

isPointInStroke()

isPointInStroke(path, x, y): boolean

Defined in: canvas/src/context.ts:438

Tests whether a point lies on the stroked outline of a path.

Parameters

Parameter	Type
path	CanvasPath
x	number
y	number

Returns

boolean

Overrides

DOMContext.isPointInStroke

---

layer()

layer<TResult>(body): TResult

Defined in: core/src/context/context.ts:470

Executes a callback within a save/restore pair, returning the callback's result.

Type Parameters

Type Parameter	Default type
TResult	void

Parameters

Parameter	Type
body	() => TResult

Returns

TResult

Inherited from

DOMContext.layer

---

markRenderEnd()

markRenderEnd(): void

Defined in: core/src/context/context.ts:509

Signals the end of a render pass.

Returns

void

Inherited from

DOMContext.markRenderEnd

---

markRenderStart()

markRenderStart(): void

Defined in: core/src/context/context.ts:500

Signals the start of a render pass; resets the rendered-elements list at depth 0.

Returns

void

Inherited from

DOMContext.markRenderStart

---

measureText()

measureText(text, font?): TextMetrics

Defined in: canvas/src/context.ts:403

Measures text dimensions using the canvas context's current font or an optional override.

Parameters

Parameter	Type
text	string
font?	string

Returns

TextMetrics

Overrides

DOMContext.measureText

---

off()

off<TEvent>(type, handler): void

Defined in: core/src/core/event-bus.ts:112

Removes a previously registered handler for the given event type.

Type Parameters

Type Parameter
TEvent extends keyof ContextEventMap

Parameters

Parameter	Type
type	TEvent
handler	EventHandler<ContextEventMap[TEvent]>

Returns

void

Inherited from

DOMContext.off

---

on()

on<TEvent>(type, handler, options?): Disposable

Defined in: core/src/core/event-bus.ts:99

Subscribes a handler to the given event type and returns a disposable for cleanup.

Type Parameters

Type Parameter
TEvent extends keyof ContextEventMap

Parameters

Parameter	Type
type	TEvent
handler	EventHandler<ContextEventMap[TEvent]>
options?	EventSubscriptionOptions

Returns

Disposable

Inherited from

DOMContext.on

---

once()

once<TEvent>(type, handler, options?): Disposable

Defined in: core/src/core/event-bus.ts:127

Subscribes a handler that is automatically removed after it fires once.

Type Parameters

Type Parameter
TEvent extends keyof ContextEventMap

Parameters

Parameter	Type
type	TEvent
handler	EventHandler<ContextEventMap[TEvent]>
options?	EventSubscriptionOptions

Returns

Disposable

Inherited from

DOMContext.once

---

popGroup()

popGroup(): void

Defined in: core/src/context/context.ts:578

Closes the most recently opened group boundary, unwinding the state stack back to the depth captured at Context.pushGroup. This absorbs any dangling save() left by a group-scoped clip (which deliberately skips its own restore so the clip persists to later siblings), confining the clip to the group rather than leaking it to the scene.

Returns

void

Inherited from

DOMContext.popGroup

---

pushGroup()

pushGroup(group): void

Defined in: core/src/context/context.ts:538

Opens a group boundary: saves the current drawing state and applies the group's own transform, inherited paint, and opacity, so that descendant elements render within the group's coordinate system, inherit its paint through the copied state (the render-tree cascade), and composite under its opacity. Any group-scoped clip is confined to the group. Every Context.pushGroup must be balanced by a matching Context.popGroup. Backends that render hierarchy structurally (such as SVG) override this to nest descendants under a group node.

Parameters

Parameter	Type	Description
group	Element	The group element whose boundary is being entered.

Returns

void

Inherited from

DOMContext.pushGroup

---

rescale()

protected rescale(width, height): void

Defined in: canvas/src/context.ts:336

Parameters

Parameter	Type
width	number
height	number

Returns

void

Overrides

DOMContext.rescale

---

reset()

reset(): void

Defined in: canvas/src/context.ts:371

Resets the canvas context to its default state.

Returns

void

Overrides

DOMContext.reset

---

restore()

restore(): void

Defined in: canvas/src/context.ts:356

Restores the most recently saved drawing state from the stack.

Returns

void

Overrides

DOMContext.restore

---

retain()

protected retain(value, key?): void

Defined in: core/src/core/disposer.ts:14

Registers a disposable resource under an optional key for later cleanup.

Parameters

Parameter	Type	Default value
value	Disposable	undefined
key	PropertyKey	Disposer.defaultKey

Returns

void

Inherited from

DOMContext.retain

---

rotate()

rotate(angle): void

Defined in: canvas/src/context.ts:376

Applies a rotation transformation, in radians.

Parameters

Parameter	Type
angle	number

Returns

void

Overrides

DOMContext.rotate

---

save()

save(): void

Defined in: canvas/src/context.ts:350

Saves the current drawing state onto the state stack.

Returns

void

Overrides

DOMContext.save

---

scale()

scale(x, y): void

Defined in: canvas/src/context.ts:381

Applies a scale transformation.

Parameters

Parameter	Type
x	number
y	number

Returns

void

Overrides

DOMContext.scale

---

setTransform()

setTransform(a, b, c, d, e, f): void

Defined in: canvas/src/context.ts:392

Replaces the current transformation matrix with the given values.

Parameters

Parameter	Type
a	number
b	number
c	number
d	number
e	number
f	number

Returns

void

Overrides

DOMContext.setTransform

---

transform()

transform(a, b, c, d, e, f): void

Defined in: canvas/src/context.ts:398

Multiplies the current transformation matrix by the given values.

Parameters

Parameter	Type
a	number
b	number
c	number
d	number
e	number
f	number

Returns

void

Overrides

DOMContext.transform

---

translate()

translate(x, y): void

Defined in: canvas/src/context.ts:386

Applies a translation transformation.

Parameters

Parameter	Type
x	number
y	number

Returns

void

Overrides

DOMContext.translate