smallthingz.ui

Reusable Kotlin primitives and an inline construction DSL for ordinary Android Views. The library supplies geometry, text/font layout, animation math and coordination, and native View construction helpers. It has no Reverb recorder or storage dependency and no Compose or Material3 UI runtime.

The DSL constructs actual Views directly. It does not retain a second UI tree or run a reconciler. This is an implementation boundary, not a measured zero-cost claim: text layout, animation, allocation and View operations still have costs.

Build

Use JDK 21 and an Android SDK with platform 37 installed. Set ANDROID_HOME or an untracked local.properties containing sdk.dir. Java and Kotlin target JVM 17; the minimum Android API is 28.

./gradlew assembleRelease testDebugUnitTest

The wrapper pins Gradle 9.7.1; the standalone build pins Android Gradle Plugin 9.4.0 and Kotlin 2.3.0. Reverb includes this checkout as :native-ui and shares its matching toolchain classloader. The Android namespace and Kotlin package root are smallthingz.ui in either build. The standalone project is kotlin-ui, with Gradle group smallthingz. Consumers import the direct View DSL from smallthingz.ui.dsl.

Animation owners

smallthingz.ui.animation supplies SpringValue, AnimatedValue, TransitionValue, and UpdatableScrollAnimation. The first two preserve typed velocity on interruption, including Color and IntSize conversion; transition channels retain raw vector momentum. Callers supply their own tween durations, visibility policies, and final paint/property updates.

The main-thread owners in smallthingz.ui.animation.view connect those samplers to frames. ViewFrameLoop uses an attached View and the caller's window clock; AttachedFrameLoop has explicit attach/detach/close boundaries on that clock. Both inherit its pause and duration-scale behavior. ViewSpringDriver is the optional direct Choreographer driver; close it when its logical owner retires. Use one driver per animation and serialize sampler updates on its owner. SOURCE-view-animation.json records the extracted sources and lifecycle fixes.

Sampler and clock-owner tests run with the unit suite. The separate scripts/test_view_animation_host.py runner accepts compiler/test classpaths and uses src/testViewHost to check View owner cancellation against a narrow host fixture. This verifies production control flow, not Android rendering or timing.

Procedural background grain

import smallthingz.ui.graphics.NoiseDrawable
import smallthingz.ui.graphics.NoiseTexture

NoiseTexture.prepare() // Optional asynchronous warmup; construction also starts it.
view.background = NoiseDrawable(
    backgroundColor = surfaceColor, // ARGB Int; null draws grain alone.
    seed = NoiseDrawable.SEED_BACKGROUND, // SEED_TOP_BAR uses the other standard phase.
)

Grain uses a fixed deterministic algorithm and a 1024 × 1024 repeating tile, generated once per process. Its ARGB bitmap has a 4 MiB pixel payload; generation reuses one 64 KiB pixel array across 64 strips, excluding allocator/object overhead. These payload sizes do not measure total process memory or generation time. There is no bundled raster or disk cache. One background worker generates the tile; drawables initially show their supplied fill and invalidate when generation finishes. Only the two standard phase shaders are cached. Ordinary drawing reuses each drawable's paints and shader; optional alpha/filter composition still has a layer cost. Callers using NoiseTexture.shader() must not mutate the shared standard-phase shader matrices. Disable platform force-dark on the owning View when exact supplied colors must be preserved.

Integration and provenance

This is an independent Git repository, extracted with its module-only history from Reverb. ORIGIN.json records the exact source snapshot and split commit. Reverb pins a Git submodule commit and supplies a compact offline Git bundle plus bootstrap script; an offline checkout does not require network access.

SOURCE-foundation.json, SOURCE-motion.json, SOURCE-motion.md, SOURCE-text.json, and src/main/resource-provenance/ retain the original upstream attribution and historical qualification records. Their native-ui/ target paths are relative to the original Reverb checkout. The package migration from app.smallthingz.nativeui to smallthingz.ui also moved the corresponding source directories from app/smallthingz/nativeui/ to smallthingz/ui/; the historical manifests retain their original paths and hashes. Old temporary source paths are historical provenance, not current build inputs. Historical validation statements are not a claim that a new checkout has passed current tests.

First-party code is licensed under Apache-2.0; see LICENSE.txt. Upstream-derived files retain their existing Apache-2.0 notices and provenance. Dependencies remain AndroidX annotation and emoji2 internally, with coroutines exposed in the existing public API.