OffscreenCanvasRenderingContext2D extension type

The OffscreenCanvasRenderingContext2D interface is a CanvasRenderingContext2D rendering context for drawing to the bitmap of an OffscreenCanvas object. It is similar to the CanvasRenderingContext2D object, with the following differences:

• there is no support for user-interface features (drawFocusIfNeeded, and scrollPathIntoView)
• its canvas attribute refers to an OffscreenCanvas object rather than a canvas element
• the bitmap for the placeholder canvas element belonging to the OffscreenCanvas object is updated during the rendering update of the Window or Worker that owns the OffscreenCanvas

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API documentation sourced from MDN Web Docs.

on

• JSObject

Implemented types

• JSObject

Available extensions

• JSAnyExtension
• JSAnyNullableExtension
• JSAnyOperatorExtension
• JSAnyUtilityExtension
• JSObjectExtension
• JSObjectUnsafeUtilExtension
• JSObjectWebExtension
• NullableUndefineableJSAnyExtension

Properties

asString → String

Available on JSAny, provided by the JSAnyExtension extension

no setter

asString → String?

Available on JSAny?, provided by the JSAnyNullableExtension extension

no setter

canvas → OffscreenCanvas

no setter

direction ↔ CanvasDirection

getter/setter pair

entries → Iterable<MapEntry<String, dynamic>>

Available on JSObject, provided by the JSObjectExtension extension

no setter

fillStyle ↔ JSAny

getter/setter pair

filter ↔ String

getter/setter pair

font ↔ String

getter/setter pair

fontKerning ↔ CanvasFontKerning

getter/setter pair

fontStretch ↔ CanvasFontStretch

getter/setter pair

fontVariantCaps ↔ CanvasFontVariantCaps

getter/setter pair

globalAlpha ↔ double

getter/setter pair

globalCompositeOperation ↔ String

getter/setter pair

hashCode → int

The hash code for this object.

no setter, inherited

imageSmoothingEnabled ↔ bool

getter/setter pair

imageSmoothingQuality ↔ ImageSmoothingQuality

getter/setter pair

isDefinedAndNotNull → bool

Available on JSAny?, provided by the NullableUndefineableJSAnyExtension extension

no setter

isElement → bool

Available on JSObject?, provided by the JSObjectWebExtension extension

no setter

isHTMLElement → bool

Available on JSObject?, provided by the JSObjectWebExtension extension

no setter

isNode → bool

Available on JSObject?, provided by the JSObjectWebExtension extension

no setter

isNull → bool

Available on JSAny?, provided by the NullableUndefineableJSAnyExtension extension

Whether this value corresponds to JavaScript null.

no setter

isTruthy → JSBoolean

Available on JSAny?, provided by the JSAnyOperatorExtension extension

The result of !!this in JavaScript.

no setter

isUndefined → bool

Available on JSAny?, provided by the NullableUndefineableJSAnyExtension extension

Whether this value corresponds to JavaScript undefined.

no setter

isUndefinedOrNull → bool

Available on JSAny?, provided by the NullableUndefineableJSAnyExtension extension

no setter

keys → Iterable<String>

Available on JSObject, provided by the JSObjectExtension extension

no setter

letterSpacing ↔ String

getter/setter pair

lineCap ↔ CanvasLineCap

getter/setter pair

lineDashOffset ↔ double

getter/setter pair

lineJoin ↔ CanvasLineJoin

getter/setter pair

lineWidth ↔ double

getter/setter pair

miterLimit ↔ double

getter/setter pair

not → JSBoolean

Available on JSAny?, provided by the JSAnyOperatorExtension extension

The result of !this in JavaScript.

no setter

runtimeType → Type

A representation of the runtime type of the object.

no setter, inherited

shadowBlur ↔ double

getter/setter pair

shadowColor ↔ String

getter/setter pair

shadowOffsetX ↔ double

getter/setter pair

shadowOffsetY ↔ double

getter/setter pair

strokeStyle ↔ JSAny

getter/setter pair

textAlign ↔ CanvasTextAlign

getter/setter pair

textBaseline ↔ CanvasTextBaseline

getter/setter pair

textRendering ↔ CanvasTextRendering

getter/setter pair

wordSpacing ↔ String

getter/setter pair

Methods

add(JSAny? any) → JSAny

Available on JSAny?, provided by the JSAnyOperatorExtension extension

The result of this + any in JavaScript.

and(JSAny? any) → JSAny?

Available on JSAny?, provided by the JSAnyOperatorExtension extension

The result of this && any in JavaScript.

arc(num x, num y, num radius, num startAngle, num endAngle, [bool counterclockwise]) → void

arcTo(num x1, num y1, num x2, num y2, num radius) → void

as<T extends JSObject>() → T?

Available on JSObject, provided by the JSObjectExtension extension

beginPath() → void

bezierCurveTo(num cp1x, num cp1y, num cp2x, num cp2y, num x, num y) → void

callMethod<R extends JSAny?>(JSAny method, [JSAny? arg1, JSAny? arg2, JSAny? arg3, JSAny? arg4]) → R

Available on JSObject, provided by the JSObjectUnsafeUtilExtension extension

Calls method on this JSObject with up to four arguments.

callMethodVarArgs<R extends JSAny?>(JSAny method, [List<JSAny?>? arguments]) → R

Available on JSObject, provided by the JSObjectUnsafeUtilExtension extension

Calls method on this JSObject with a variable number of arguments.

clearRect(num x, num y, num w, num h) → void

clip([JSAny fillRuleOrPath, CanvasFillRule fillRule]) → void

closePath() → void

createConicGradient(num startAngle, num x, num y) → CanvasGradient

createImageData(JSAny imagedataOrSw, [int sh, ImageDataSettings settings]) → ImageData

createLinearGradient(num x0, num y0, num x1, num y1) → CanvasGradient

createPattern(CanvasImageSource image, String repetition) → CanvasPattern?

createRadialGradient(num x0, num y0, num r0, num x1, num y1, num r1) → CanvasGradient

dartify() → Object?

Available on JSAny?, provided by the JSAnyUtilityExtension extension

Converts a JavaScript JSON-like value to the Dart equivalent if possible.

delete(JSAny property) → JSBoolean

Available on JSObject, provided by the JSObjectUnsafeUtilExtension extension

Deletes the property with key property from this JSObject.

divide(JSAny? any) → JSAny

Available on JSAny?, provided by the JSAnyOperatorExtension extension

The result of this / any in JavaScript.

drawImage(CanvasImageSource image, num dxOrSx, num dyOrSy, [num dwOrSw, num dhOrSh, num dx, num dy, num dw, num dh]) → void

ellipse(num x, num y, num radiusX, num radiusY, num rotation, num startAngle, num endAngle, [bool counterclockwise]) → void

equals(JSAny? any) → JSBoolean

Available on JSAny?, provided by the JSAnyOperatorExtension extension

The result of this == any in JavaScript.

exponentiate(JSAny? any) → JSAny

Available on JSAny?, provided by the JSAnyOperatorExtension extension

The result of this ** any in JavaScript.

fill([JSAny fillRuleOrPath, CanvasFillRule fillRule]) → void

fillRect(num x, num y, num w, num h) → void

fillText(String text, num x, num y, [num maxWidth]) → void

get(String key) → Object?

Available on JSObject, provided by the JSObjectExtension extension

getImageData(int sx, int sy, int sw, int sh, [ImageDataSettings settings]) → ImageData

getLineDash() → JSArray<JSNumber>

getProperty<R extends JSAny?>(JSAny property) → R

Available on JSObject, provided by the JSObjectUnsafeUtilExtension extension

The value of the property key property of this JSObject.

getTransform() → DOMMatrix

greaterThan(JSAny? any) → JSBoolean

Available on JSAny?, provided by the JSAnyOperatorExtension extension

The result of this > any in JavaScript.

greaterThanOrEqualTo(JSAny? any) → JSBoolean

Available on JSAny?, provided by the JSAnyOperatorExtension extension

The result of this >= any in JavaScript.

has(String property) → bool

Available on JSObject, provided by the JSObjectUnsafeUtilExtension extension

Shorthand helper for hasProperty to check whether this JSObject contains the property key property, but takes and returns a Dart value.

hasProperty(JSAny property) → JSBoolean

Available on JSObject, provided by the JSObjectUnsafeUtilExtension extension

Whether or not this JSObject contains the property key property.

instanceof(JSFunction constructor) → bool

Available on JSAny?, provided by the JSAnyUtilityExtension extension

Whether this JSAny? is an instanceof constructor.

instanceOfString(String constructorName) → bool

Available on JSAny?, provided by the JSAnyUtilityExtension extension

Whether this JSAny? is an instanceof the constructor that is defined by constructorName, which is looked up in the globalContext.

isA<T extends JSAny?>() → bool

Available on JSAny?, provided by the JSAnyUtilityExtension extension

Whether this JSAny? is an instance of the JavaScript type that is declared by T.

isContextLost() → bool

isPointInPath(JSAny pathOrX, num xOrY, [JSAny fillRuleOrY, CanvasFillRule fillRule]) → bool

isPointInStroke(JSAny pathOrX, num xOrY, [num y]) → bool

lessThan(JSAny? any) → JSBoolean

Available on JSAny?, provided by the JSAnyOperatorExtension extension

The result of this < any in JavaScript.

lessThanOrEqualTo(JSAny? any) → JSBoolean

Available on JSAny?, provided by the JSAnyOperatorExtension extension

The result of this <= any in JavaScript.

lineTo(num x, num y) → void

measureText(String text) → TextMetrics

modulo(JSAny? any) → JSAny

Available on JSAny?, provided by the JSAnyOperatorExtension extension

The result of this % any in JavaScript.

moveTo(num x, num y) → void

multiply(JSAny? any) → JSAny

Available on JSAny?, provided by the JSAnyOperatorExtension extension

The result of this * any in JavaScript.

noSuchMethod(Invocation invocation) → dynamic

Invoked when a nonexistent method or property is accessed.

inherited

notEquals(JSAny? any) → JSBoolean

Available on JSAny?, provided by the JSAnyOperatorExtension extension

The result of this != any in JavaScript.

or(JSAny? any) → JSAny?

Available on JSAny?, provided by the JSAnyOperatorExtension extension

The result of this || any in JavaScript.

put(Object key, Object? value) → void

Available on JSObject, provided by the JSObjectExtension extension

putImageData(ImageData imagedata, int dx, int dy, [int dirtyX, int dirtyY, int dirtyWidth, int dirtyHeight]) → void

quadraticCurveTo(num cpx, num cpy, num x, num y) → void

rect(num x, num y, num w, num h) → void

reset() → void

resetTransform() → void

restore() → void

rotate(num angle) → void

roundRect(num x, num y, num w, num h, [JSAny radii]) → void

save() → void

scale(num x, num y) → void

setLineDash(JSArray<JSNumber> segments) → void

setProperty(JSAny property, JSAny? value) → void

Available on JSObject, provided by the JSObjectUnsafeUtilExtension extension

Write the value of property key property of this JSObject.

setTransform([JSAny aOrTransform, num b, num c, num d, num e, num f]) → void

strictEquals(JSAny? any) → JSBoolean

Available on JSAny?, provided by the JSAnyOperatorExtension extension

The result of this === any in JavaScript.

strictNotEquals(JSAny? any) → JSBoolean

Available on JSAny?, provided by the JSAnyOperatorExtension extension

The result of this !== any in JavaScript.

stroke([Path2D path]) → void

strokeRect(num x, num y, num w, num h) → void

strokeText(String text, num x, num y, [num maxWidth]) → void

subtract(JSAny? any) → JSAny

Available on JSAny?, provided by the JSAnyOperatorExtension extension

The result of this - any in JavaScript.

toMap() → Map<String, dynamic>

Available on JSObject, provided by the JSObjectExtension extension

toString() → String

A string representation of this object.

inherited

transform(num a, num b, num c, num d, num e, num f) → void

translate(num x, num y) → void

typeofEquals(String typeString) → bool

Available on JSAny?, provided by the JSAnyUtilityExtension extension

Whether the result of typeof on this JSAny? is typeString.

unsignedRightShift(JSAny? any) → JSNumber

Available on JSAny?, provided by the JSAnyOperatorExtension extension

The result of this >>> any in JavaScript.

Operators

operator ==(Object other) → bool

The equality operator.

inherited

operator [](String property) → JSAny?

Available on JSObject, provided by the JSObjectUnsafeUtilExtension extension

Shorthand helper for getProperty to get the value of the property key property of this JSObject, but takes a Dart value.

operator []=(String property, JSAny? value) → void

Available on JSObject, provided by the JSObjectUnsafeUtilExtension extension

Shorthand helper for setProperty to write the value of the property key property of this JSObject, but takes a Dart value.