AnnotatedRegionLayer<T extends Object> class

A composited layer which annotates its children with a value. Pushing this layer to the tree is the common way of adding an annotation.

An annotation is an optional object of any type that, when attached with a layer, can be retrieved using Layer.find or Layer.findAllAnnotations with a position. The search process is done recursively, controlled by a concept of being opaque to a type of annotation, explained in the document of Layer.findAnnotations.

When an annotation search arrives, this layer defers the same search to each of this layer's children, respecting their opacity. Then it adds this layer's annotation if all of the following restrictions are met:

  • The target type must be identical to the annotated type T.
  • If size is provided, the target position must be contained within the rectangle formed by size and offset.

This layer is opaque to a type of annotation if any child is also opaque, or if opaque is true and the layer's annotation is added.

Inheritance

Constructors

AnnotatedRegionLayer(T value, {Size? size, Offset? offset, bool opaque = false})
Creates a new layer that annotates its children with value.

Properties

alwaysNeedsAddToScene → bool
Subclasses may override this to true to disable retained rendering.
no setterinherited
attached → bool
Whether the layer tree containing this layer is attached to an owner.
no setterinherited
debugCreator ↔ Object?
The object responsible for creating this layer.
getter/setter pairinherited
debugDisposed → bool
If asserts are enabled, returns whether dispose has been called since the last time any retained resources were created.
no setterinherited
debugHandleCount → int
Returns the number of objects holding a LayerHandle to this layer.
no setterinherited
debugSubtreeNeedsAddToScene → bool?
Whether this or any descendant layer in the subtree needs addToScene.
no setterinherited
depth → int
The depth of this layer in the layer tree.
no setterinherited
engineLayer ↔ EngineLayer?
Stores the engine layer created for this layer in order to reuse engine resources across frames for better app performance.
getter/setter pairinherited
firstChild → Layer?
The first composited layer in this layer's child list.
no setterinherited
hasChildren → bool
Returns whether this layer has at least one child layer.
no setterinherited
hashCode → int
The hash code for this object.
no setterinherited
lastChild → Layer?
The last composited layer in this layer's child list.
no setterinherited
nextSibling → Layer?
This layer's next sibling in the parent layer's child list.
no setterinherited
offset → Offset
The position of the annotated object.
final
opaque → bool
Whether the annotation of this layer should be opaque during an annotation search of type T, preventing siblings visually behind it from being searched.
final
owner → Object?
The owner for this layer (null if unattached).
no setterinherited
parent → ContainerLayer?
This layer's parent in the layer tree.
no setterinherited
previousSibling → Layer?
This layer's previous sibling in the parent layer's child list.
no setterinherited
runtimeType → Type
A representation of the runtime type of the object.
no setterinherited
size → Size?
The size of the annotated object.
final
subtreeHasCompositionCallbacks → bool
Whether the subtree rooted at this layer has any composition callback observers.
no setterinherited
value → T
The annotated object, which is added to the result if all restrictions are met.
final

Methods

addChildrenToScene(SceneBuilder builder) → void
Uploads all of this layer's children to the engine.
inherited
addCompositionCallback(CompositionCallback callback) → VoidCallback
Adds a callback for when the layer tree that this layer is part of gets composited, or when it is detached and will not be rendered again.
inherited
addToScene(SceneBuilder builder) → void
Override this method to upload this layer to the engine.
inherited
append(Layer child) → void
Adds the given layer to the end of this layer's child list.
inherited
applyTransform(Layer? child, Matrix4 transform) → void
Applies the transform that would be applied when compositing the given child to the given matrix.
inherited
attach(covariant Object owner) → void
Mark this layer as attached to the given owner.
inherited
buildScene(SceneBuilder builder) → Scene
Consider this layer as the root and build a scene (a tree of layers) in the engine.
inherited
debugDescribeChildren() → List<DiagnosticsNode>
Returns a list of DiagnosticsNode objects describing this node's children.
inherited
debugFillProperties(DiagnosticPropertiesBuilder properties) → void
Add additional properties associated with the node.
override
debugMarkClean() → void
Mark that this layer is in sync with engine.
inherited
depthFirstIterateChildren() → List<Layer>
Returns the descendants of this layer in depth first order.
inherited
describeClipBounds() → Rect?
Describes the clip that would be applied to contents of this layer, if any.
inherited
detach() → void
Mark this layer as detached from its owner.
inherited
dispose() → void
Clears any retained resources that this layer holds.
inherited
find<S extends Object>(Offset localPosition) → S?
Search this layer and its subtree for the first annotation of type S under the point described by localPosition.
inherited
findAllAnnotations<S extends Object>(Offset localPosition) → AnnotationResult<S>
Search this layer and its subtree for all annotations of type S under the point described by localPosition.
inherited
findAnnotations<S extends Object>(AnnotationResult<S> result, Offset localPosition, {required bool onlyFirst}) → bool
Searches the subtree for annotations of type S at the location localPosition, then adds the annotation value if applicable.
override
markNeedsAddToScene() → void
Mark that this layer has changed and addToScene needs to be called.
inherited
noSuchMethod(Invocation invocation) → dynamic
Invoked when a nonexistent method or property is accessed.
inherited
redepthChild(Layer child) → void
Adjust the depth of the given child to be greater than this node's own depth.
inherited
redepthChildren() → void
Adjust the depth of this node's children, if any.
inherited
remove() → void
Removes this layer from its parent layer's child list.
inherited
removeAllChildren() → void
Removes all of this layer's children from its child list.
inherited
supportsRasterization() → bool
Whether or not this layer, or any child layers, can be rasterized with ui.Scene.toImage or ui.Scene.toImageSync.
inherited
toDiagnosticsNode({String? name, DiagnosticsTreeStyle? style}) → DiagnosticsNode
Returns a debug representation of the object that is used by debugging tools and by DiagnosticsNode.toStringDeep.
inherited
toString({DiagnosticLevel minLevel = DiagnosticLevel.info}) → String
A string representation of this object.
inherited
toStringDeep({String prefixLineOne = '', String? prefixOtherLines, DiagnosticLevel minLevel = DiagnosticLevel.debug, int wrapWidth = 65}) → String
Returns a string representation of this node and its descendants.
inherited
toStringShallow({String joiner = ', ', DiagnosticLevel minLevel = DiagnosticLevel.debug}) → String
Returns a one-line detailed description of the object.
inherited
toStringShort() → String
A brief description of this object, usually just the runtimeType and the hashCode.
inherited
updateSubtreeNeedsAddToScene() → void
Traverses the layer subtree starting from this layer and determines whether it needs addToScene.
inherited

Operators

operator ==(Object other) → bool
The equality operator.
inherited