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Class: PhaseFlow

Defined in: animation/movement/Homotopy.ts:459

Animation that flows a mobject along a vector field. The mobject follows the flow lines defined by the vector field function.

Uses the RK4 ODE solver from utils/ode for accurate numerical integration.

Example​

// Circular flow
const flow = new PhaseFlow(dots, {
  vectorField: ([x, y, z]) => [-y, x, 0],
  virtualTime: 2,
  duration: 3,
});

Extends​

Constructors​

Constructor​

new PhaseFlow(mobject, options): PhaseFlow

Defined in: animation/movement/Homotopy.ts:481

Parameters​

mobject​

Mobject

options​

PhaseFlowOptions

Returns​

PhaseFlow

Overrides​

Animation.constructor

Properties​

_hasBegun​

protected _hasBegun: boolean = false

Defined in: animation/Animation.ts:49

Track if begin() has been called

Inherited from​

Animation._hasBegun

_isFinished​

protected _isFinished: boolean = false

Defined in: animation/Animation.ts:46

Whether the animation has finished

Inherited from​

Animation._isFinished

_startTime​

protected _startTime: number = null

Defined in: animation/Animation.ts:43

Time when the animation started (set by Timeline)

Inherited from​

Animation._startTime

duration​

readonly duration: number

Defined in: animation/Animation.ts:37

Duration of the animation in seconds

Inherited from​

Animation.duration

mobject​

readonly mobject: Mobject

Defined in: animation/Animation.ts:34

The mobject being animated

Inherited from​

Animation.mobject

rateFunc​

readonly rateFunc: RateFunction

Defined in: animation/Animation.ts:40

Rate function controlling the animation's pacing

Inherited from​

Animation.rateFunc

remover​

remover: boolean = false

Defined in: animation/Animation.ts:55

If true, the scene will remove this mobject after the animation finishes. Used by FadeOut (like Python manim's remover=True).

Inherited from​

Animation.remover

vectorField​

readonly vectorField: VectorFieldFunction

Defined in: animation/movement/Homotopy.ts:461

The vector field function

virtualTime​

readonly virtualTime: number

Defined in: animation/movement/Homotopy.ts:464

Virtual time to flow through

Accessors​

startTime​

Get Signature​

get startTime(): number

Defined in: animation/Animation.ts:220

Get the start time of this animation (set by Timeline)

Returns​

number

Set Signature​

set startTime(time): void

Defined in: animation/Animation.ts:227

Set the start time of this animation (used by Timeline)

Parameters​
time​

number

Returns​

void

Inherited from​

Animation.startTime

Methods​

begin()​

begin(): void

Defined in: animation/movement/Homotopy.ts:491

Store the original points at animation start

Returns​

void

Overrides​

Animation.begin

cleanUpFromScene()​

cleanUpFromScene(scene): void

Defined in: animation/Animation.ts:141

Hook called by Scene after the animation finishes, before the next play(). Default: removes mobject if remover is set (FadeOut, Write({remover:true})). Override for animations that need to mutate scene membership — e.g. ReplacementTransform swaps source for target.

Parameters​

scene​

AnimationScene

Returns​

void

Inherited from​

Animation.cleanUpFromScene

finish()​

finish(): void

Defined in: animation/movement/Homotopy.ts:559

Ensure the final state is exact

Returns​

void

Overrides​

Animation.finish

interpolate()​

interpolate(alpha): void

Defined in: animation/movement/Homotopy.ts:515

Apply the phase flow at the given progress value.

Each point is flowed from its original position for alpha * virtualTime using RK4 integration. The vector field is sampled in WORLD space: local points are lifted through the world matrix, flowed, then pushed back through the inverse. World === local when untransformed.

Parameters​

alpha​

number

Returns​

void

Overrides​

Animation.interpolate

isFinished()​

isFinished(): boolean

Defined in: animation/Animation.ts:181

Check if the animation has finished

Returns​

boolean

Inherited from​

Animation.isFinished

reset()​

reset(): void

Defined in: animation/Animation.ts:190

Reset the animation to its initial state. Restores the mobject to its pre-animation visual state so that re-seeking (especially backward) produces correct results.

Returns​

void

Inherited from​

Animation.reset

update()​

update(_dt, currentTime): void

Defined in: animation/Animation.ts:158

Update the animation for the current frame.

Parameters​

_dt​

number

Time delta since last frame (unused, but available for subclasses)

currentTime​

number

Current time in the timeline

Returns​

void

Inherited from​

Animation.update