Skip to main content

Class: ValueTracker

Defined in: mobjects/value-tracker/ValueTracker.ts:71

ValueTracker - Tracks a numerical value that can be animated.

This is an invisible mobject designed to hold a single numerical value that can be smoothly animated. It's commonly used with updaters to create dynamic animations where multiple mobjects respond to a single changing value.

Extends​

Constructors​

Constructor​

new ValueTracker(value?): ValueTracker

Defined in: mobjects/value-tracker/ValueTracker.ts:79

Create a new ValueTracker.

Parameters​

value?​

number

Initial value (default: 0)

Returns​

ValueTracker

Overrides​

Mobject.constructor

Constructor​

new ValueTracker(options?): ValueTracker

Defined in: mobjects/value-tracker/ValueTracker.ts:80

Parameters​

options?​

ValueTrackerOptions

Returns​

ValueTracker

Overrides​

Mobject.constructor

Properties​

__savedMobjectState​

__savedMobjectState: unknown = null

Defined in: core/Mobject.ts:95

JSON-serializable saved state (used by restoreState()).

Inherited from​

Mobject.__savedMobjectState

_color​

protected _color: string = '#ffffff'

Defined in: core/Mobject.ts:70

Inherited from​

Mobject._color

_dirty​

_dirty: boolean = true

Defined in: core/Mobject.ts:88

Inherited from​

Mobject._dirty

_disableChildZLayering​

protected _disableChildZLayering: boolean = false

Defined in: core/Mobject.ts:85

When true, children skip the 2D z-layering offset in _syncToThree.

Inherited from​

Mobject._disableChildZLayering

_opacity​

protected _opacity: number = 1

Defined in: core/Mobject.ts:81

Inherited from​

Mobject._opacity

_style​

protected _style: MobjectStyle

Defined in: core/Mobject.ts:86

Inherited from​

Mobject._style

_threeObject​

_threeObject: Object3D<Object3DEventMap> = null

Defined in: core/Mobject.ts:87

Inherited from​

Mobject._threeObject

children​

children: Mobject[] = []

Defined in: core/Mobject.ts:65

Inherited from​

Mobject.children

createdAtBeginning​

createdAtBeginning: boolean = false

Defined in: core/Mobject.ts:69

Inherited from​

Mobject.createdAtBeginning

fillOpacity​

fillOpacity: number = 0

Defined in: core/Mobject.ts:83

Inherited from​

Mobject.fillOpacity

id​

readonly id: string

Defined in: core/Mobject.ts:63

Inherited from​

Mobject.id

parent​

parent: Mobject = null

Defined in: core/Mobject.ts:64

Inherited from​

Mobject.parent

position​

position: Vector3

Defined in: core/Mobject.ts:66

Inherited from​

Mobject.position

rotation​

rotation: Euler

Defined in: core/Mobject.ts:67

Inherited from​

Mobject.rotation

savedState​

savedState: Mobject = null

Defined in: core/Mobject.ts:91

Saved mobject copy (used by Restore animation). Set by saveState().

Inherited from​

Mobject.savedState

scaleVector​

scaleVector: Vector3

Defined in: core/Mobject.ts:68

Inherited from​

Mobject.scaleVector

strokeWidth​

strokeWidth: number = 4

Defined in: core/Mobject.ts:82

Inherited from​

Mobject.strokeWidth

targetCopy​

targetCopy: Mobject = null

Defined in: core/Mobject.ts:93

Target copy used by generateTarget() / MoveToTarget animation.

Inherited from​

Mobject.targetCopy

Accessors​

animate​

Get Signature​

get animate(): any

Defined in: core/Mobject.ts:497

Returns an AnimateProxy that records method calls. Pass the proxy to scene.play() to animate from the current state to the state after all recorded calls are applied.

Example​
scene.play(circle.animate.shift([2, 0, 0]));
scene.play(circle.animate.setColor('#ff0000').scale(2));
Returns​

any

Inherited from​

Mobject.animate

color​

Get Signature​

get color(): string

Defined in: core/Mobject.ts:71

Returns​

string

Set Signature​

set color(value): void

Defined in: core/Mobject.ts:74

Parameters​
value​

string

Returns​

void

Inherited from​

Mobject.color

fillColor​

Get Signature​

get fillColor(): string

Defined in: core/Mobject.ts:184

Returns​

string

Set Signature​

set fillColor(color): void

Defined in: core/Mobject.ts:188

Parameters​
color​

string

Returns​

void

Inherited from​

Mobject.fillColor

isDirty​

Get Signature​

get isDirty(): boolean

Defined in: core/Mobject.ts:551

Returns​

boolean

Inherited from​

Mobject.isDirty

opacity​

Get Signature​

get opacity(): number

Defined in: core/Mobject.ts:114

Returns​

number

Set Signature​

set opacity(value): void

Defined in: core/Mobject.ts:118

Parameters​
value​

number

Returns​

void

Inherited from​

Mobject.opacity

strokeColor​

Get Signature​

get strokeColor(): string

Defined in: core/Mobject.ts:195

Returns​

string

Set Signature​

set strokeColor(color): void

Defined in: core/Mobject.ts:199

Parameters​
color​

string

Returns​

void

Inherited from​

Mobject.strokeColor

style​

Get Signature​

get style(): MobjectStyle

Defined in: core/Mobject.ts:122

Returns​

MobjectStyle

Inherited from​

Mobject.style

submobjects​

Get Signature​

get submobjects(): Mobject[]

Defined in: core/Mobject.ts:136

Returns​

Mobject[]

Inherited from​

Mobject.submobjects

Methods​

_createCopy()​

protected _createCopy(): ValueTracker

Defined in: mobjects/value-tracker/ValueTracker.ts:157

Create a copy of this ValueTracker.

Returns​

ValueTracker

A new ValueTracker with the same value

Overrides​

Mobject._createCopy

_createThreeObject()​

protected _createThreeObject(): Object3D

Defined in: mobjects/value-tracker/ValueTracker.ts:165

Create an empty Three.js object (ValueTracker is invisible).

Returns​

Object3D

An empty THREE.Group

Overrides​

Mobject._createThreeObject

_getBoundingBox()​

_getBoundingBox(): object

Defined in: core/Mobject.ts:449

Returns​

object

depth​

depth: number

height​

height: number

width​

width: number

Deprecated​

Use getBoundingBox() instead.

Inherited from​

Mobject._getBoundingBox

_getEdgeInDirection()​

_getEdgeInDirection(direction): Vector3Tuple

Defined in: core/Mobject.ts:442

Parameters​

direction​

Vector3Tuple

Returns​

Vector3Tuple

Inherited from​

Mobject._getEdgeInDirection

_markDirty()​

_markDirty(): void

Defined in: core/Mobject.ts:541

Returns​

void

Inherited from​

Mobject._markDirty

_markDirtyUpward()​

_markDirtyUpward(): void

Defined in: core/Mobject.ts:545

Returns​

void

Inherited from​

Mobject._markDirtyUpward

_syncMaterialToThree()​

protected _syncMaterialToThree(): void

Defined in: core/Mobject.ts:539

Returns​

void

Inherited from​

Mobject._syncMaterialToThree

_syncToThree()​

_syncToThree(): void

Defined in: core/Mobject.ts:519

Returns​

void

Inherited from​

Mobject._syncToThree

add()​

add(...mobjects): this

Defined in: core/Mobject.ts:329

Parameters​

mobjects​

...Mobject[]

Returns​

this

Inherited from​

Mobject.add

addUpdater()​

addUpdater(updater, callOnAdd): this

Defined in: core/Mobject.ts:589

Parameters​

updater​

UpdaterFunction

callOnAdd​

boolean = false

Returns​

this

Inherited from​

Mobject.addUpdater

alignTo()​

alignTo(target, direction): this

Defined in: core/Mobject.ts:427

Parameters​

target​

Mobject | Vector3Tuple

direction​

Vector3Tuple

Returns​

this

Inherited from​

Mobject.alignTo

animateTo()​

animateTo(targetValue, options?): Animation

Defined in: mobjects/value-tracker/ValueTracker.ts:141

Create an animation that smoothly changes the value.

Parameters​

targetValue​

number

The value to animate to

options?​

AnimationOptions

Animation options (duration, rateFunc, etc.)

Returns​

Animation

An animation that can be added to a timeline

Example​

// Animate from current value to 10 over 2 seconds
timeline.add(tracker.animateTo(10, { duration: 2 }));

// Animate with custom rate function
timeline.add(tracker.animateTo(5, {
  duration: 1.5,
  rateFunc: easeInOut
}));

applyFunction()​

applyFunction(fn, options?): this

Defined in: core/Mobject.ts:619

Parameters​

fn​

(point) => number[]

options?​
aboutEdge?​

Vector3Tuple

aboutPoint?​

Vector3Tuple

Returns​

this

Inherited from​

Mobject.applyFunction

applyMatrix()​

applyMatrix(matrix, options?): this

Defined in: core/Mobject.ts:627

Parameters​

matrix​

number[][]

options?​
aboutEdge?​

Vector3Tuple

aboutPoint?​

Vector3Tuple

Returns​

this

Inherited from​

Mobject.applyMatrix

applyToFamily()​

applyToFamily(func): this

Defined in: core/Mobject.ts:577

Parameters​

func​

(mobject) => void

Returns​

this

Inherited from​

Mobject.applyToFamily

become()​

become(other): this

Defined in: core/Mobject.ts:376

Parameters​

other​

Mobject

Returns​

this

Inherited from​

Mobject.become

center()​

center(): this

Defined in: core/Mobject.ts:479

Returns​

this

Inherited from​

Mobject.center

clearUpdaters()​

clearUpdaters(): this

Defined in: core/Mobject.ts:601

Returns​

this

Inherited from​

Mobject.clearUpdaters

copy()​

copy(): Mobject

Defined in: core/Mobject.ts:358

Returns​

Mobject

Inherited from​

Mobject.copy

dispose()​

dispose(): void

Defined in: core/Mobject.ts:658

Returns​

void

Inherited from​

Mobject.dispose

flip()​

flip(axis, options?): this

Defined in: core/Mobject.ts:257

Parameters​

axis​

Vector3Tuple = ...

options?​
aboutEdge?​

Vector3Tuple

aboutPoint?​

Vector3Tuple

Returns​

this

Inherited from​

Mobject.flip

generateTarget()​

generateTarget(): Mobject

Defined in: core/Mobject.ts:642

Returns​

Mobject

Inherited from​

Mobject.generateTarget

getBottom()​

getBottom(): Vector3Tuple

Defined in: core/Mobject.ts:458

Returns​

Vector3Tuple

Inherited from​

Mobject.getBottom

getBoundingBox()​

getBoundingBox(): object

Defined in: core/Mobject.ts:445

Returns​

object

depth​

depth: number

height​

height: number

width​

width: number

Inherited from​

Mobject.getBoundingBox

getBounds()​

getBounds(): object

Defined in: core/Mobject.ts:392

Returns​

object

max​

max: object

max.x​

x: number

max.y​

y: number

max.z​

z: number

min​

min: object

min.x​

x: number

min.y​

y: number

min.z​

z: number

Inherited from​

Mobject.getBounds

getCenter()​

getCenter(): Vector3Tuple

Defined in: mobjects/value-tracker/ValueTracker.ts:149

Get the center position (returns origin since this is invisible).

Returns​

Vector3Tuple

[0, 0, 0]

Overrides​

Mobject.getCenter

getDisplayMeshes()​

getDisplayMeshes(): Mesh<BufferGeometry<NormalBufferAttributes, BufferGeometryEventMap>, Material<MaterialEventMap> | Material<MaterialEventMap>[], Object3DEventMap>[]

Defined in: core/Mobject.ts:569

Returns​

Mesh<BufferGeometry<NormalBufferAttributes, BufferGeometryEventMap>, Material<MaterialEventMap> | Material<MaterialEventMap>[], Object3DEventMap>[]

Inherited from​

Mobject.getDisplayMeshes

getDisplayMeshLength()​

getDisplayMeshLength(): number

Defined in: core/Mobject.ts:565

Number of visible display meshes this mobject contributes when rendered. Used for Transform eligibility checks without forcing Three.js object creation.

Returns​

number

Inherited from​

Mobject.getDisplayMeshLength

getEdge()​

getEdge(direction): Vector3Tuple

Defined in: core/Mobject.ts:452

Parameters​

direction​

Vector3Tuple

Returns​

Vector3Tuple

Inherited from​

Mobject.getEdge

getFamily()​

getFamily(): Mobject[]

Defined in: core/Mobject.ts:583

Returns​

Mobject[]

Inherited from​

Mobject.getFamily

getLeft()​

getLeft(): Vector3Tuple

Defined in: core/Mobject.ts:461

Returns​

Vector3Tuple

Inherited from​

Mobject.getLeft

getRight()​

getRight(): Vector3Tuple

Defined in: core/Mobject.ts:464

Returns​

Vector3Tuple

Inherited from​

Mobject.getRight

getThreeObject()​

getThreeObject(): Object3D

Defined in: core/Mobject.ts:555

Returns​

Object3D

Inherited from​

Mobject.getThreeObject

getTop()​

getTop(): Vector3Tuple

Defined in: core/Mobject.ts:455

Returns​

Vector3Tuple

Inherited from​

Mobject.getTop

getUpdaters()​

getUpdaters(): UpdaterFunction[]

Defined in: core/Mobject.ts:608

Returns​

UpdaterFunction[]

Inherited from​

Mobject.getUpdaters

getValue()​

getValue(): number

Defined in: mobjects/value-tracker/ValueTracker.ts:97

Get the current value.

Returns​

number

The current tracked value

hasUpdaters()​

hasUpdaters(): boolean

Defined in: core/Mobject.ts:605

Returns​

boolean

Inherited from​

Mobject.hasUpdaters

incrementValue()​

incrementValue(amount): this

Defined in: mobjects/value-tracker/ValueTracker.ts:119

Increment the value by a given amount.

Parameters​

amount​

number

The amount to add (can be negative)

Returns​

this

this for chaining

moveTo()​

moveTo(target, alignedEdge?): this

Defined in: core/Mobject.ts:216

Parameters​

target​

Mobject | Vector3Tuple

alignedEdge?​

Vector3Tuple

Returns​

this

Inherited from​

Mobject.moveTo

moveToAligned()​

moveToAligned(target, alignedEdge?): this

Defined in: core/Mobject.ts:437

Parameters​

target​

Mobject | Vector3Tuple

alignedEdge?​

Vector3Tuple

Returns​

this

Inherited from​

Mobject.moveToAligned

nextTo()​

nextTo(target, direction, buff): this

Defined in: core/Mobject.ts:410

Parameters​

target​

Mobject | Vector3Tuple

direction​

Vector3Tuple = RIGHT

buff​

number = 0.25

Returns​

this

Inherited from​

Mobject.nextTo

prepareForNonlinearTransform()​

prepareForNonlinearTransform(numPieces): this

Defined in: core/Mobject.ts:635

Parameters​

numPieces​

number = 50

Returns​

this

Inherited from​

Mobject.prepareForNonlinearTransform

remove()​

remove(...mobjects): this

Defined in: core/Mobject.ts:342

Parameters​

mobjects​

...Mobject[]

Returns​

this

Inherited from​

Mobject.remove

removeUpdater()​

removeUpdater(updater): this

Defined in: core/Mobject.ts:595

Parameters​

updater​

UpdaterFunction

Returns​

this

Inherited from​

Mobject.removeUpdater

replace()​

replace(target, stretch): this

Defined in: core/Mobject.ts:381

Parameters​

target​

Mobject

stretch​

boolean = false

Returns​

this

Inherited from​

Mobject.replace

restoreState()​

restoreState(): boolean

Defined in: core/Mobject.ts:652

Returns​

boolean

Inherited from​

Mobject.restoreState

rotate()​

rotate(angle, axisOrOptions?): this

Defined in: core/Mobject.ts:237

Rotate the mobject by angle around an axis. Accepts aboutPoint or aboutEdge to specify the rotation center.

Parameters​

angle​

number

axisOrOptions?​

Vector3Tuple | { aboutEdge?: Vector3Tuple; aboutPoint?: Vector3Tuple; axis?: Vector3Tuple; }

Returns​

this

Inherited from​

Mobject.rotate

rotateAboutOrigin()​

rotateAboutOrigin(angle, axis): this

Defined in: core/Mobject.ts:253

Parameters​

angle​

number

axis​

Vector3Tuple = ...

Returns​

this

Inherited from​

Mobject.rotateAboutOrigin

saveState()​

saveState(): this

Defined in: core/Mobject.ts:647

Returns​

this

Inherited from​

Mobject.saveState

scale()​

scale(factor, options?): this

Defined in: core/Mobject.ts:283

Parameters​

factor​

number | Vector3Tuple

options?​
aboutEdge?​

Vector3Tuple

aboutPoint?​

Vector3Tuple

Returns​

this

Inherited from​

Mobject.scale

setColor()​

setColor(color): this

Defined in: core/Mobject.ts:140

Parameters​

color​

string

Returns​

this

Inherited from​

Mobject.setColor

setFill()​

setFill(color?, opacity?): this

Defined in: core/Mobject.ts:178

Parameters​

color?​

string

opacity?​

number

Returns​

this

Inherited from​

Mobject.setFill

setFillOpacity()​

setFillOpacity(opacity): this

Defined in: core/Mobject.ts:168

Parameters​

opacity​

number

Returns​

this

Inherited from​

Mobject.setFillOpacity

setStrokeOpacity()​

setStrokeOpacity(opacity): this

Defined in: core/Mobject.ts:148

Parameters​

opacity​

number

Returns​

this

Inherited from​

Mobject.setStrokeOpacity

setStrokeWidth()​

setStrokeWidth(width): this

Defined in: core/Mobject.ts:158

Parameters​

width​

number

Returns​

this

Inherited from​

Mobject.setStrokeWidth

setStyle()​

setStyle(style): this

Defined in: core/Mobject.ts:126

Parameters​

style​

Partial<MobjectStyle>

Returns​

this

Inherited from​

Mobject.setStyle

setValue()​

setValue(value): this

Defined in: mobjects/value-tracker/ValueTracker.ts:106

Set the value directly (without animation).

Parameters​

value​

number

The new value

Returns​

this

this for chaining

setX()​

setX(x): this

Defined in: core/Mobject.ts:467

Parameters​

x​

number

Returns​

this

Inherited from​

Mobject.setX

setY()​

setY(y): this

Defined in: core/Mobject.ts:471

Parameters​

y​

number

Returns​

this

Inherited from​

Mobject.setY

setZ()​

setZ(z): this

Defined in: core/Mobject.ts:475

Parameters​

z​

number

Returns​

this

Inherited from​

Mobject.setZ

shift()​

shift(delta): this

Defined in: core/Mobject.ts:208

Parameters​

delta​

Vector3Tuple

Returns​

this

Inherited from​

Mobject.shift

stretch()​

stretch(factor, dim, options?): this

Defined in: core/Mobject.ts:310

Parameters​

factor​

number

dim​

number

options?​
aboutEdge?​

Vector3Tuple

aboutPoint?​

Vector3Tuple

Returns​

this

Inherited from​

Mobject.stretch

toCorner()​

toCorner(direction, buff, frameDimensions?): this

Defined in: core/Mobject.ts:509

Parameters​

direction​

Vector3Tuple = ...

buff​

number = 0.5

frameDimensions?​

[number, number]

Returns​

this

Inherited from​

Mobject.toCorner

toEdge()​

toEdge(direction, buff, frameDimensions?): this

Defined in: core/Mobject.ts:504

Parameters​

direction​

Vector3Tuple

buff​

number = 0.5

frameDimensions?​

[number, number]

Returns​

this

Inherited from​

Mobject.toEdge

update()​

update(dt): void

Defined in: core/Mobject.ts:612

Parameters​

dt​

number

Returns​

void

Inherited from​

Mobject.update