Tween
A Tween defines an interpolation that will modify one or many attribute(s) of an object during a specified time. This modification can be done smoothly and with various effects easily, this is the main purpose of Tweens !
- see the Tween.java source code
The easiest way to create a tween is to use one of the static constructors:
public static Tween to(Tweenable target, int tweenType, int duration)public static Tween from(Tweenable target, int tweenType, int duration)public static Tween set(Tweenable target, int tweenType)public static Tween call(IterationCompleteCallback callback)
Some explanations:
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Tween.to()creates the most common tween. It interpolates between the current values and the target values. -
Tween.from()creates a reverse tween. It interpolates between the target values and the current values. -
Tween.set()defines an instantaneous tween. It will apply the target values directly, without interpolation. -
Tween.call()does not define an interpolation, but helps you to create a simple timer.
Of course, Tween.set() and Tween.call() are best used with a delay applied to them. See below for options such as delays.
The previously listed tweens are useless if you do not specify their target values. Just call the .target() method on your tweens. Since there are many overloads for this method, it is not included in the static constructors. Just don't forget it ;-)
The method returns the current tween, so you can easily chain it:
Tween.to(...).target(x, y, z);
Many options can be added to your tweens. Most of these optional methods return the current tween, so you can chain them in one line.
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.ease(TweenEquation equation): sets the easing function of the tween. -
.delay(int delay): adds a delay to the tween. -
.setCallback(TweenCallback callback): sets a callback to the tween. There are many available callbacks, to listen for the end of a tween iteration, for its full completion, etc. -
.repeat(int count, int delay): repeats the tween for a given number of times. -
.repeatYoyo(int count, int delay): repeats the tween for a given number of times with a yoyo style.
Combined tweens are tweens that act on more than one attribute at a time. Just return a number higher than 1 in the getValues() method of the TweenAccessor interface for some tween type, and you can use Tween.to()/.from()/.set() with many attributes at a time.
Tween.to(myObject, MY_COMBINED_TYPE, 1.0f).target(value1, value2, value3);
Its a very powerful feature, especially useful when you want to tween, for instance, the position of an object as a whole XY position, and not with two tweens (one for X, one for Y).