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:
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.
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].
