Core APICore API

A definition describes a motion, starting it returns a handle, and the handle controls that one playback. These pages list every member of each, with the exact rules the guides leave out. Anatomy of a Tween draws every field.

Examples use using Godot; and using tweens.gd;, which also covers definitions such as Tweens.Position2D.

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Describe

• Definitions: Tweens.* and TweenOptions
• Endpoints & variations: From, To, By, factors
• Timing: Duration, Repeats, FillMode
• Callbacks: OnAdd through OnFinally

Shape

• Easing: EaseType, BlendType, curves
• Effects: punch, shake, and breathe

Play

• Starting playback: Tween(), PlaybackOptions
• Handles: TweenInstance, Reason
• Groups: parallel steps
• Chains: linked timelines

Extend

• Custom definitions: TweenDefinition
• Scheduler: TweenScheduler
• Catalog: every built-in definition

Coming from Godot’s Tween

Both blink a sprite out three times:

Godot's Tween

var tween = sprite.CreateTween().SetLoops(3);
tween.TweenProperty(sprite, "modulate:a", 0f, 0.2).From(1f);

tweens.gd

var blink = new Tweens.ModulateAlpha(0, 0.2) { From = 1, Repeats = 2 };

sprite.Tween(blink);

Godot’s Tween	tweens.gd
TweenProperty(...)	A definition, started with node.Tween(definition)
From(value), AsRelative()	From, By
SetTrans(...), SetEase(...)	One Ease, such as Out.Cubic
SetDelay(seconds)	Delay
SetLoops(count)	Repeats, which counts cycles after the first: SetLoops(3) is Repeats = 2, and SetLoops() is TweenOptions.Infinite
A second tween back to the start	PingPong
SetParallel(), Parallel()	node.Tween(first, second), or Group.Of
Tweeners in sequence, TweenInterval(seconds)	node.Chain([...]), with a Delay on the next entry
TweenCallback(...)	A callback, such as OnEnd
TweenMethod(...)	Tweens.Float and the other callback values
Finished signal	await handle.End, which also resumes when playback stops early
Pause(), Play(), Kill()	Pause(), Resume(), Cancel()
SetProcessMode, SetPauseMode, SetIgnoreTimeScale	PlaybackOptions
BindNode(node)	The node you start on, or a resource tween’s owner

Differences from GDScript

Both implementations share their timing, easing, grouping, and lifetime rules, and shared fixtures test both. The differences come from the languages:

Area	C#	GDScript
Names	PascalCase: From, To, By	snake_case: from_value, to_value, by_value
Starts	node.Tween(definition), node.Tween(a, b)	Tweens.play(node, definition), Tweens.play_all(node, [a, b])
Definitions	Immutable values, varied with with	Mutable objects, varied with with_*() copies
Type checks	Generic TweenInstance<TTarget, TValue>, checked by the compiler	Target class and value type checked when playback starts
Failures	Awaiting faults with an exception; Error holds it	Awaiting end returns FAILED; error holds a message
Script errors	Exceptions from callbacks and setters fault the tween	Detected problems become FAILED; other errors stay Godot script errors
Integer values	Saturate at 32-bit limits	Saturate at signed 64-bit limits; shader integers stay 32-bit
Callbacks	Synchronous	Synchronous; await end from a separate coroutine instead of inside one

See the GDScript core API for its entry points.