LiquidMorphPhysics class

Pure, stateless math engine for liquid glass morphing animations.

This class implements the J-curve back-out position curve and Curves.linearToEaseOut size curve that together create the iOS 26 liquid teardrop morphing effect.

It is intentionally stateless — feed it the raw animation value plus the source/destination geometry and it returns a fully computed LiquidMorphState for that frame. No BuildContext, no State, no ChangeNotifier dependencies.

Design

Two conceptual blobs drive the morph:

• Blob A (anchor / ghost trigger) stays at the trigger position and shrinks away over the first 40 % of the animation to cleanly break the liquid bridge.
• Blob B (menu body) travels from the trigger center to the menu center along a J-curve overshoot trajectory, expanding from trigger size to menu size.

The metaball SDF shader automatically creates the teardrop neck between the two blobs — there is no explicit neck geometry.

Usage

// Typically called from an AnimatedBuilder or addListener callback.
final state = LiquidMorphPhysics.compute(
  rawValue: controller.value,
  finalDx: finalDx,
  finalDy: finalDy,
  horizontalOffset: _horizontalOffset,
  verticalOffset: _verticalOffset,
);

// Apply to the UI:
Positioned(
  left: triggerX + state.pushDx,
  top:  triggerY + state.pushDy,
  child: Transform.scale(scale: state.anchorScale, child: blobA),
)

Properties

hashCode → int

The hash code for this object.

no setter, inherited

runtimeType → Type

A representation of the runtime type of the object.

no setter, inherited

Methods

noSuchMethod(Invocation invocation) → dynamic

Invoked when a nonexistent method or property is accessed.

inherited

toString() → String

A string representation of this object.

inherited

Operators

operator ==(Object other) → bool

The equality operator.

inherited

Static Methods

compute({required double rawValue, required double finalDx, required double finalDy, double horizontalOffset = 0.0, double verticalOffset = 0.0}) → LiquidMorphState

Computes the full LiquidMorphState for a single animation frame.

Constants

closeSpring → const SpringDescription

Spring profile for the iOS 26 liquid morph closing animation.

closeVelocityHint → const double

Initial velocity hint injected when the close animation starts.

openSpring → const SpringDescription

Spring profile for the iOS 26 liquid morph opening animation.