Lumentika

Lumentika is a retained UI runtime for Kotlin/JVM. It includes reactive state, a component DSL, Taffy-based layout, retained rendering and hit testing, input and focus, gestures, text editing, accessibility semantics, styles, and animation.

Artifacts

com.antepod:lumentika-core:<version>
com.antepod:lumentika-ksp:<version>

lumentika-core contains the runtime and public UI API. Rendering environments integrate it through interfaces for frame scheduling, paint replay, text layout, input, images, accessibility, and other services.

Features

• Fine-grained state, derived values, effects, batching, async state, and owned cleanup
• Kotlin component DSL with generated props, bindings, events, and slots
• Block, flex, and grid layout backed by Taffy4J
• Extensible paints; retained paths, rounded clips, borders, shadows, property trees, and hit testing
• Pointer, keyboard, focus, gestures, nested scrolling, text editing, clipboard, drag/drop, and autofill contracts
• Accessibility semantics with stable nodes, actions, ranges, collections, and live regions
• Typed styles, state conditions, themes, logical units, and environment-aware values
• Explicit paint, intrinsic-measurement, and text-metrics invalidation for retained content
• Tween and spring style animation; enter/exit, keyed layout, draw, blur, and crossfade animation
• Headless services for deterministic tests

Built-in UI building blocks include block, flex, row, column, grid, stack, scroll, list, text, image, button, checkbox, slider, textField, and tooltip.

One rule applies across the public DSL: function arguments configure a component; a trailing UI lambda is child or default-slot content only. Leaf components have no trailing UI lambda.

Installation

Use the same release version for both artifacts. The KSP artifact is only needed when declaring custom @UIComponent classes.

plugins {
    kotlin("jvm") version "<kotlin-version>"
    id("com.google.devtools.ksp") version "<ksp-version>"
}

dependencies {
    implementation("com.antepod:lumentika-core:<version>")
    ksp("com.antepod:lumentika-ksp:<version>")
}

Releases are available from Maven Central.

Quick start

The headless root is useful for examples and tests. Applications create UiRoot with the services required by their rendering environment.

import com.antepod.lumentika.components.*
import com.antepod.lumentika.headlessRoot
import com.antepod.lumentika.reactive.derived
import com.antepod.lumentika.reactive.state
import com.antepod.lumentika.style.*

val root = headlessRoot(640f, 360f)
val volume = state(50f)
val enabled = state(true)
val title = derived { "Volume: ${volume.value.toInt()}%" }

val rootStyle = style {
    width = 320.px
    padding = edges(16.px)
    gap = 8.px
    background = rgb(24, 26, 32)
    color = rgb(245, 245, 245)
}

root.scope.column(style = rootStyle) {
    text(value = title)

    slider(value = volume, min = 0f, max = 100f, step = 1f)
    checkbox(checked = enabled, label = "Enabled")
    button(value = "Reset", onClick = { volume.value = 50f })
}

root.requestFrame()
root.frame(1_000_000L)
root.close()

The root owns the mounted tree and all runtime subsystems. Close it when its UI surface is destroyed.

Documentation

• Getting started
• Core concepts and custom components
• Built-in components
• Styling and themes
• Animation and structural transitions
• Architecture and platform boundary
• Platform adapter guide
• Contributing and verification

License

Licensed under the Apache License 2.0.