MorphAnchor class

The declarative layer on top of the engine: a morph as a function of state, in the spirit of SwiftUI's matchedGeometryEffect, adapted to Flutter's rules.

The anchor and the overlay are colocated in the tree (like MenuAnchor); the source of truth is isOpen owned by the state holder. Opening, closing, and interruption are just a bool flip: toggled mid-flight - the spring retargets with velocity carry-over. A scrim tap and Esc do not close the overlay themselves; they call onDismiss - state flows down, events flow up.

Identity is implicit: the State itself serves as the tag (analogous to a SwiftUI Namespace); no global string ids required.

MorphAnchor(
  isOpen: _sharing,
  onDismiss: () => setState(() => _sharing = false),
  target: MorphTargetSpec.sheet(),
  shape: const StadiumBorder(),
  closedBuilder: (context) =>
      ShareButton(onTap: () => setState(() => _sharing = true)),
  openBuilder: (context) => ShareSheet(),
)

The imperative showMorph remains alongside as an escape hatch - like showDialog next to OpenContainer.

Inheritance

Constructors

MorphAnchor({Key? key, required bool isOpen, required VoidCallback onDismiss, required MorphTargetSpec target, required WidgetBuilder closedBuilder, required MorphContentBuilder openBuilder, Object? tagId, MorphSurfaceSpec? spec, ShapeBorder shape = const RoundedRectangleBorder(), Color? surfaceColor, double elevation = 0, Widget? replica, bool snapshotGhost = false, MorphMotion? motion, bool barrierDismissible = true, double? maxScrimOpacity, Color? scrimColor, Color? shadowColor, String? semanticLabel})
Creates a declarative morph driven by isOpen.
const

Properties

barrierDismissible → bool
Whether scrim taps and Esc request dismissal.
final
closedBuilder → WidgetBuilder
Builds the inline widget (the flight's source).
final
elevation → double
The source elevation (MorphTag.elevation semantics): a source with its own shadow must declare it, or the shadow pops at launch and handoff.
final
hashCode → int
The hash code for this object.
no setterinherited
isOpen → bool
Whether the overlay should be open; changes retarget the flight.
final
key → Key?
Controls how one widget replaces another widget in the tree.
finalinherited
maxScrimOpacity → double?
Scrim ceiling; null resolves MorphTheme, then the default.
final
motion → MorphMotion?
Motion profile; null resolves MorphTheme, then the default.
final
onDismiss → VoidCallback
Called when the user dismisses (scrim tap, Esc, back): flip the state that feeds isOpen - state down, events up.
final
openBuilder → MorphContentBuilder
Builds the overlay content. Rebuilt when the anchor rebuilds, so content derived from the owner's state stays fresh in the open overlay.
final
replica → Widget?
The in-flight copy for the shuttle (MorphTag.replica semantics).
final
runtimeType → Type
A representation of the runtime type of the object.
no setterinherited
scrimColor → Color?
Scrim hue; null resolves MorphTheme, then black.
final
semanticLabel → String?
Accessibility name of the opened overlay (screen readers announce it).
final
shadowColor → Color?
Shadow color of the flying surface, opacity included; null resolves MorphTheme, then 60% black.
final
shape → ShapeBorder
The source outline the shuttle takes off from.
final
snapshotGhost → bool
Fly a pixel snapshot instead of a widget replica (MorphTag.snapshotGhost semantics).
final
spec → MorphSurfaceSpec?
The source surface model as one value (MorphTag.spec semantics: wins over shape/surfaceColor/elevation).
final
surfaceColor → Color?
The source surface color.
final
tagId → Object?
An explicit tag id instead of identity-by-State. Needed when the anchor's flight must be visible to outside consumers by name - for example, a MorphPiece with the same id gets the flight neck for free. Must stay stable for the anchor's whole lifetime.
final
target → MorphTargetSpec
The destination description.
final

Methods

createElement() → StatefulElement
Creates a StatefulElement to manage this widget's location in the tree.
inherited
createState() → State<MorphAnchor>
Creates the mutable state for this widget at a given location in the tree.
override
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.
inherited
noSuchMethod(Invocation invocation) → dynamic
Invoked when a nonexistent method or property is accessed.
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 short, textual description of this widget.
inherited

Operators

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