StyleAnimation

Since 2.2.1

StyleAnimation is a runtime style animator for UIElement.
Use it when you want to animate style properties directly in code (for example on click, hover, or custom events), instead of relying only on passive transition.

---

Usage

UIElement.animation() automatically selects the current element as the animation target.

target.animation()
        .duration(1f)
        .ease(Eases.QUAD_IN_OUT)
        .style(PropertyRegistry.TRANSFORM_2D, new Transform2D().scale(0.5f).translate(100f, 0))
        .style(PropertyRegistry.OPACITY, 0f)
        .onFinished(element -> {
            target.animation()
                    .ease(Eases.QUART_IN_OUT)
                    .style(PropertyRegistry.TRANSFORM_2D, new Transform2D())
                    .style(PropertyRegistry.OPACITY, 1f)
                    .start();
        })
        .start();

target.animationDsl {
    duration(1f)
    ease(Eases.QUAD_IN_OUT)
    style(PropertyRegistry.TRANSFORM_2D, Transform2D().scale(0.5f).translate(100f, 0f))
    style(PropertyRegistry.OPACITY, 0f)
    onFinished {
        target.animationDsl {
            ease(Eases.QUART_IN_OUT)
            style(PropertyRegistry.TRANSFORM_2D, Transform2D())
            style(PropertyRegistry.OPACITY, 1f)
        }
    }
}

target.animation()
    .duration(1)
    .ease(Eases.QUAD_IN_OUT)
    .style(PropertyRegistry.OPACITY, 0)
    .lss("width", 250)
    .onFinished(element => {
        target.animation()
            .ease(Eases.QUART_IN_OUT)
            .style(PropertyRegistry.OPACITY, 1)
            .lss("width", 100)
            .start();
    })
    .start();

---

Tips

WARNING

StyleAnimation.start() only works when ModularUI is valid (non-null).

If you want an enter animation (play once when the element is mounted into a valid ModularUI), use the callback overload:

target.animation(anim -> {
    anim.duration(0.5f)
        .ease(Eases.QUART_OUT)
        .style(PropertyRegistry.OPACITY, 1f)
        .start();
});

The callback is invoked immediately when ModularUI is already available, or once after UIEvents.MUI_CHANGED when it becomes available.

target.animationDsl {
    duration(0.5f)
    ease(Eases.QUART_OUT)
    style(PropertyRegistry.OPACITY, 1f)
}

Kotlin DSL does not usually need extra start() handling:

• animationDsl { ... } defaults to start = true
• animation execution is deferred until ModularUI becomes valid

---

Keyframes

style(property, frames...) supports keyframes by progress (0.0 -> 1.0).

target.animation()
        .duration(2f)
        .ease(Eases.QUAD_IN_OUT)
        .style(PropertyRegistry.OPACITY,
                FloatObjectPair.of(0.5f, 0f))
        .start();

target.animationDsl {
    duration(2f)
    ease(Eases.QUAD_IN_OUT)
    style(PropertyRegistry.OPACITY,
        at(0.5f, 0f)
    )
}

// KubeJS commonly uses single target values:
target.animation()
    .duration(2)
    .style(PropertyRegistry.OPACITY, 0)
    .start();

---

Target Selection

For multi-target animation, create an animation from ModularUI and select by element or selector.

StyleAnimation.of(mui)
        .select(targetElement)
        .select(".card:hover")
        .lss("opacity", 0.5f)
        .start();

StyleAnimation.of(mui)
    .select(targetElement)
    .select(".card:hover")
    .lss("opacity", 0.5f)
    .start()

StyleAnimation.of(mui)
    .select(".card:hover")
    .lss("opacity", 0.5)
    .start();

---

Lifecycle and Control

start() returns ISubscription.
Call unsubscribe() to stop/cancel the running animation subscription.

You can also configure:

• duration(float)
• delay(float)
• ease(IEase)
• onInterpolate((runtime, element) -> ...)
• onFinished(element -> ...)
• origin(StyleOrigin) and animationOrigin(StyleOrigin) for advanced style-origin control

---

API Reference

Method	Returns	Description
select(UIElement)	StyleAnimation	Adds one element target.
select(String)	StyleAnimation	Selects targets by selector on current ModularUI.
style(Property<T>, T)	StyleAnimation	Animates one property to a final value.
style(Property<T>, FloatObjectPair...)	StyleAnimation	Animates one property with keyframes.
lss(String, Object)	StyleAnimation	Sets target property by LSS property name and value string/object.
duration(float)	StyleAnimation	Sets animation duration in seconds.
delay(float)	StyleAnimation	Sets start delay in seconds.
ease(IEase)	StyleAnimation	Sets easing function.
onInterpolate(BiConsumer<AnimationRuntime, UIElement>)	StyleAnimation	Called every animation frame update.
onFinished(Consumer<UIElement>)	StyleAnimation	Called when animation finishes per target/property completion flow.
start()	ISubscription	Starts the animation.