Tweens are mostly useful for animations requiring a numerical property to be interpolated over a range of values. The name [i]tween[/i] comes from [i]in-betweening[/i], an animation technique where you specify [i]keyframes[/i] and the computer interpolates the frames that appear between them. Animating something with a [Tween] is called tweening.
[Tween] is more suited than [AnimationPlayer] for animations where you don't know the final values in advance. For example, interpolating a dynamically-chosen camera zoom value is best done with a [Tween]; it would be difficult to do the same thing with an [AnimationPlayer] node. Tweens are also more light-weight than [AnimationPlayer], so they are very much suited for simple animations or general tasks that don't require visual tweaking provided by the editor. They can be used in a fire-and-forget manner for some logic that normally would be done by code. You can e.g. make something shoot periodically by using a looped [CallbackTweener] with a delay.
A [Tween] can be created by using either [method SceneTree.create_tween] or [method Node.create_tween]. [Tween]s created manually (i.e. by using [code]Tween.new()[/code]) are invalid and can't be used for tweening values.
A tween animation is created by adding [Tweener]s to the [Tween] object, using [method tween_property], [method tween_interval], [method tween_callback] or [method tween_method]:
This sequence will make the [code]$Sprite[/code] node turn red, then shrink, before finally calling [method Node.queue_free] to free the sprite. [Tweener]s are executed one after another by default. This behavior can be changed using [method parallel] and [method set_parallel].
When a [Tweener] is created with one of the [code]tween_*[/code] methods, a chained method call can be used to tweak the properties of this [Tweener]. For example, if you want to set a different transition type in the above example, you can use [method set_trans]:
Most of the [Tween] methods can be chained this way too. In the following example the [Tween] is bound to the running script's node and a default transition is set for its [Tweener]s:
You should avoid using more than one [Tween] per object's property. If two or more tweens animate one property at the same time, the last one created will take priority and assign the final value. If you want to interrupt and restart an animation, consider assigning the [Tween] to a variable:
Some [Tweener]s use transitions and eases. The first accepts a [enum TransitionType] constant, and refers to the way the timing of the animation is handled (see [url=https://easings.net/]easings.net[/url] for some examples). The second accepts an [enum EaseType] constant, and controls where the [code]trans_type[/code] is applied to the interpolation (in the beginning, the end, or both). If you don't know which transition and easing to pick, you can try different [enum TransitionType] constants with [constant EASE_IN_OUT], and use the one that looks best.
[b]Note:[/b] All [Tween]s will automatically start by default. To prevent a [Tween] from autostarting, you can call [method stop] immediately after it is created.
[b]Note:[/b] [Tween]s are processing after all of nodes in the current frame, i.e. after [method Node._process] or [method Node._physics_process] (depending on [enum TweenProcessMode]).
Binds this [Tween] with the given [param node]. [Tween]s are processed directly by the [SceneTree], so they run independently of the animated nodes. When you bind a [Node] with the [Tween], the [Tween] will halt the animation when the object is not inside tree and the [Tween] will be automatically killed when the bound object is freed. Also [constant TWEEN_PAUSE_BOUND] will make the pausing behavior dependent on the bound node.
Processes the [Tween] by the given [param delta] value, in seconds. This is mostly useful for manual control when the [Tween] is paused. It can also be used to end the [Tween] animation immediately, by setting [param delta] longer than the whole duration of the [Tween] animation.
[b]Note:[/b] The [Tween] will become invalid in the next processing frame after its animation finishes. Calling [method stop] after performing [method custom_step] instead keeps and resets the [Tween].
Returns the total time in seconds the [Tween] has been animating (i.e. the time since it started, not counting pauses etc.). The time is affected by [method set_speed_scale], and [method stop] will reset it to [code]0[/code].
[b]Note:[/b] As it results from accumulating frame deltas, the time returned after the [Tween] has finished animating will be slightly greater than the actual [Tween] duration.
This method can be used for manual interpolation of a value, when you don't want [Tween] to do animating for you. It's similar to [method @GlobalScope.lerp], but with support for custom transition and easing.
[param initial_value] is the starting value of the interpolation.
[param delta_value] is the change of the value in the interpolation, i.e. it's equal to [code]final_value - initial_value[/code].
[param elapsed_time] is the time in seconds that passed after the interpolation started and it's used to control the position of the interpolation. E.g. when it's equal to half of the [param duration], the interpolated value will be halfway between initial and final values. This value can also be greater than [param duration] or lower than 0, which will extrapolate the value.
[param duration] is the total time of the interpolation.
[b]Note:[/b] If [param duration] is equal to [code]0[/code], the method will always return the final value, regardless of [param elapsed_time] provided.
Returns whether the [Tween] is valid. A valid [Tween] is a [Tween] contained by the scene tree (i.e. the array from [method SceneTree.get_processed_tweens] will contain this [Tween]). A [Tween] might become invalid when it has finished tweening, is killed, or when created with [code]Tween.new()[/code]. Invalid [Tween]s can't have [Tweener]s appended.
Calling this method without arguments will make the [Tween] run infinitely, until either it is killed with [method kill], the [Tween]'s bound node is freed, or all the animated objects have been freed (which makes further animation impossible).
[b]Warning:[/b] Make sure to always add some duration/delay when using infinite loops. To prevent the game freezing, 0-duration looped animations (e.g. a single [CallbackTweener] with no delay) are stopped after a small number of loops, which may produce unexpected results. If a [Tween]'s lifetime depends on some node, always use [method bind_node].
Creates and appends a [CallbackTweener]. This method can be used to call an arbitrary method in any object. Use [method Callable.bind] to bind additional arguments for the call.
Example: object that keeps shooting every 1 second.
[codeblock]
var tween = get_tree().create_tween().set_loops()
tween.tween_callback(shoot).set_delay(1)
[/codeblock]
Example: turning a sprite red and then blue, with 2 second delay.
Creates and appends an [IntervalTweener]. This method can be used to create delays in the tween animation, as an alternative to using the delay in other [Tweener]s, or when there's no animation (in which case the [Tween] acts as a timer). [param time] is the length of the interval, in seconds.
Creates and appends a [MethodTweener]. This method is similar to a combination of [method tween_callback] and [method tween_property]. It calls a method over time with a tweened value provided as an argument. The value is tweened between [param from] and [param to] over the time specified by [param duration], in seconds. Use [method Callable.bind] to bind additional arguments for the call. You can use [method MethodTweener.set_ease] and [method MethodTweener.set_trans] to tweak the easing and transition of the value or [method MethodTweener.set_delay] to delay the tweening.
Creates and appends a [PropertyTweener]. This method tweens a [param property] of an [param object] between an initial value and [param final_val] in a span of time equal to [param duration], in seconds. The initial value by default is the property's value at the time the tweening of the [PropertyTweener] starts. For example:
will move the sprite to position (100, 200) and then to (200, 300). If you use [method PropertyTweener.from] or [method PropertyTweener.from_current], the starting position will be overwritten by the given value instead. See other methods in [PropertyTweener] to see how the tweening can be tweaked further.
[b]Note:[/b] You can find the correct property name by hovering over the property in the Inspector. You can also provide the components of a property directly by using [code]"property:component"[/code] (eg. [code]position:x[/code]), where it would only apply to that particular component.
Example: moving object twice from the same position, with different transition types.
[b]Note:[/b] The [Tween] is removed (invalidated) in the next processing frame after this signal is emitted. Calling [method stop] inside the signal callback will prevent the [Tween] from being removed.
Emitted when a full loop is complete (see [method set_loops]), providing the loop index. This signal is not emitted after the final loop, use [signal finished] instead for this case.
Emitted when one step of the [Tween] is complete, providing the step index. One step is either a single [Tweener] or a group of [Tweener]s running in parallel.
If the [Tween] has a bound node, it will process when that node can process (see [member Node.process_mode]). Otherwise it's the same as [constant TWEEN_PAUSE_STOP].
