OffscreenCanvas

class OffscreenCanvas extends EventTarget

Annotations: @Native.new("OffscreenCanvas")

Inheritance

Object → EventTarget → OffscreenCanvas

Constructors

OffscreenCanvas() factory

factory OffscreenCanvas(int width, int height)

Implementation

factory OffscreenCanvas(int width, int height) {
  return OffscreenCanvas._create_1(width, height);
}

Properties

hashCode no setter inherited

int get hashCode

Inherited from Interceptor.

Implementation

int get hashCode => Primitives.objectHashCode(this);

height read / write

int? get height

Implementation

int? get height native;

set height(int? value) native;

on no setter inherited

Events get on

This is an ease-of-use accessor for event streams which should only be used when an explicit accessor is not available.

Inherited from EventTarget.

Implementation

Events get on => new Events(this);

runtimeType no setter inherited

Type get runtimeType

Inherited from Interceptor.

Implementation

Type get runtimeType =>
    getRuntimeTypeOfInterceptorNotArray(getInterceptor(this), this);

width read / write

int? get width

Implementation

int? get width native;

set width(int? value) native;

Methods

addEventListener() inherited

void addEventListener(
  String type,
  (dynamic Function(Event event))? listener, [
  bool? useCapture,
])

Inherited from EventTarget.

Implementation

void addEventListener(
  String type,
  EventListener? listener, [
  bool? useCapture,
]) {
  // TODO(leafp): This check is avoid a bug in our dispatch code when
  // listener is null.  The browser treats this call as a no-op in this
  // case, so it's fine to short-circuit it, but we should not have to.
  if (listener != null) {
    _addEventListener(type, listener, useCapture);
  }
}

convertToBlob()

Future<Blob> convertToBlob([Map<dynamic, dynamic>? options])

Implementation

Future<Blob> convertToBlob([Map? options]) {
  var options_dict = null;
  if (options != null) {
    options_dict = convertDartToNative_Dictionary(options);
  }
  return promiseToFuture<Blob>(
    JS("creates:Blob;", "#.convertToBlob(#)", this, options_dict),
  );
}

dispatchEvent() inherited

bool dispatchEvent(Event event)

Inherited from EventTarget.

Implementation

bool dispatchEvent(Event event) native;

getContext()

Object? getContext(String contextType, [Map<dynamic, dynamic>? attributes])

Implementation

Object? getContext(String contextType, [Map? attributes]) {
  if (attributes != null) {
    var attributes_1 = convertDartToNative_Dictionary(attributes);
    return _getContext_1(contextType, attributes_1);
  }
  return _getContext_2(contextType);
}

noSuchMethod() inherited

dynamic noSuchMethod(Invocation invocation)

Invoked when a nonexistent method or property is accessed.

A dynamic member invocation can attempt to call a member which doesn't exist on the receiving object. Example:

dynamic object = 1;
object.add(42); // Statically allowed, run-time error

This invalid code will invoke the noSuchMethod method of the integer 1 with an Invocation representing the .add(42) call and arguments (which then throws).

Classes can override noSuchMethod to provide custom behavior for such invalid dynamic invocations.

A class with a non-default noSuchMethod invocation can also omit implementations for members of its interface. Example:

class MockList<T> implements List<T> {
  noSuchMethod(Invocation invocation) {
    log(invocation);
    super.noSuchMethod(invocation); // Will throw.
  }
}
void main() {
  MockList().add(42);
}

This code has no compile-time warnings or errors even though the MockList class has no concrete implementation of any of the List interface methods. Calls to List methods are forwarded to noSuchMethod, so this code will log an invocation similar to Invocation.method(#add, [42]) and then throw.

If a value is returned from noSuchMethod, it becomes the result of the original invocation. If the value is not of a type that can be returned by the original invocation, a type error occurs at the invocation.

The default behavior is to throw a NoSuchMethodError.

Inherited from Interceptor.

Implementation

dynamic noSuchMethod(Invocation invocation) {
  throw NoSuchMethodError.withInvocation(this, invocation);
}

removeEventListener() inherited

void removeEventListener(
  String type,
  (dynamic Function(Event event))? listener, [
  bool? useCapture,
])

Inherited from EventTarget.

Implementation

void removeEventListener(
  String type,
  EventListener? listener, [
  bool? useCapture,
]) {
  // TODO(leafp): This check is avoid a bug in our dispatch code when
  // listener is null.  The browser treats this call as a no-op in this
  // case, so it's fine to short-circuit it, but we should not have to.
  if (listener != null) {
    _removeEventListener(type, listener, useCapture);
  }
}

toString() inherited

String toString()

A string representation of this object.

Some classes have a default textual representation, often paired with a static parse function (like int.parse). These classes will provide the textual representation as their string representation.

Other classes have no meaningful textual representation that a program will care about. Such classes will typically override toString to provide useful information when inspecting the object, mainly for debugging or logging.

Inherited from Interceptor.

Implementation

String toString() => Primitives.objectToHumanReadableString(this);

transferToImageBitmap()

ImageBitmap transferToImageBitmap()

Implementation

ImageBitmap transferToImageBitmap() native;

Operators

operator ==() inherited

bool operator ==(Object other)

The equality operator.

The default behavior for all Objects is to return true if and only if this object and other are the same object.

Override this method to specify a different equality relation on a class. The overriding method must still be an equivalence relation. That is, it must be:

• Total: It must return a boolean for all arguments. It should never throw.

• Reflexive: For all objects o, o == o must be true.

• Symmetric: For all objects o1 and o2, o1 == o2 and o2 == o1 must either both be true, or both be false.

• Transitive: For all objects o1, o2, and o3, if o1 == o2 and o2 == o3 are true, then o1 == o3 must be true.

The method should also be consistent over time, so whether two objects are equal should only change if at least one of the objects was modified.

If a subclass overrides the equality operator, it should override the hashCode method as well to maintain consistency.

Inherited from Interceptor.

Implementation

bool operator ==(Object other) => identical(this, other);