# Changelog

All notable changes to `chart-realtime` documented here.

Format follows [Keep a Changelog](https://keepachangelog.com/en/1.1.0/).
Project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html) from `1.0.0` onward.

Pre-`1.0.0` releases share the `0.5.0-SNAPSHOT` Maven coordinate per
`group:dev.dtrentin`, `artifact:chart-realtime`. Stable coordinates and Maven
Central publishing land in `1.0.0`.

## [Unreleased]

### Changed
- KGP 2.3 / AGP 9 deprecation warnings cleanup (in progress)

## [0.5.0] — 2026-05-22 — Architecture + Interaction

### Added
- **Interaction layer (T7)** — pinch zoom, drag pan, tap crosshair via `ChartInteractionState`
  + `rememberChartInteractionState()`. `ViewportMode` sealed (`Following` / `Frozen` /
  `History(anchorMs)`). Swipe-to-right-edge resumes `Following`. `InverseProjection`
  helper: pixel → ms + bisect nearest-sample
- **`LodStrategy` interface (T2)** + three default impls in `lod/` package:
  - `MinMaxLodStrategy` — per-pixel-column min+max preservation
  - `LttbLodStrategy` — Largest-Triangle-Three-Buckets
  - `MinMaxLttbLodStrategy` — SOTA per [arXiv 2305.00332](https://arxiv.org/abs/2305.00332),
    1.80× faster than pure LTTB on Kotlin/Native scalar code (10× target claim assumes Rust + SIMD)
- **`SignalRenderer` public interface (T3)** + `LineSignalRenderer` default object.
  Custom renderer impl-able in ~30 LOC. Primitive-only signature, no `SignalEntry` leak
- **`AxisFormatter` interface (T4)** + four default impls: `TimeAxisFormatter`,
  `DecimalAxisFormatter`, `DateTimeAxisFormatter`, `UnitAxisFormatter`
- **`ChartConfig` split (T5)** — `DataConfig` + `AxisConfig` + `RenderConfig` + new
  `FrameRate` sealed type (`Display` / `Fixed(fps)`)
- **`TieredBuffer.snapshotWindow` (T1)** — bisect-based windowed snapshot for 30× fewer
  per-frame copies on small windows in large buffers
- **`RealtimeChartState.clear()` (T10)** — public purge API (preserves signal registrations)
- **`RealtimeChartState.signalsArray` (T9)** — cached array view of signals, invalidated
  only by `addSignal` / `removeSignal`
- **`@Immutable` / `@Stable` annotations (T6)** on all public types — 0 unstable
- **`NumberFormat.formatFixed` overflow guard (D4)** — routes to scientific @ `|v|≥1e19`

### Changed (BREAKING)
- **Removed `LodMode` enum** — replaced by `LodStrategy` interface
- **Removed `LodDecimator` internal class** — replaced by `LodStrategy` impls
- **Removed `ChartConfig.targetFps` field** — replaced by `RenderConfig.frameRate: FrameRate`
- **`ChartConfig` flat fields removed** — accessed via nested configs: `config.data.xWindowSeconds`,
  `config.render.theme`, `config.axis.xLabelMode`, etc. Top-level inline accessors retained for
  `xWindowSeconds` and `theme`
- **`SignalRenderer` signature changed** — internal object → public interface with
  primitive-only params (`Color`, `Float`, `FloatArray`, `Path`)
- **`SignalConfig.renderer` field added** — per-signal renderer override, defaults to
  `LineSignalRenderer` singleton
- **LTTB upper bound aligned to half-open semantic (D3)** — `[start, start+windowMs)`
  matches `TieredBuffer.snapshot`. Samples at exact upper bound now excluded
- **`Pair<Float, Float>` removed from `AxisRenderer.resolveYRange`** — replaced by
  `FloatArray` out param

### Performance
- LineSignalRenderer caches `Stroke` instances per strokeWidth (T8)
- AxisRenderer caches `TextStyle` instances (16-entry cap)
- Render path: 0 `Pair`/`Map`/`Iterator` allocations per frame at steady state

### Toolchain
- Kotlin 2.1.0 → 2.3.21
- Compose Multiplatform 1.8.0 → 1.11.0
- Android Gradle Plugin 8.7.3 → 9.2.0
- Gradle 8.11.1 → 9.5.1
- coroutines 1.9.0 → 1.11.0; kotlin-test → 2.3.21
- **Dropped `kotlinx-datetime`** — replaced by stdlib `kotlin.time.Clock` (Kotlin 2.3 stable)
- **Dropped `iosX64` target** — Compose Multiplatform 1.11.0 no longer ships `ios_x64`
  variants (Intel Mac iOS simulators deprecated by Apple since Xcode 15+)

### Tests
- 107 → **207** (+100). Coverage: `lod/` (24), `interaction/` (29), `model/ChartConfigTest` (8),
  `render/AxisFormatterTest` (10), `RealtimeChartStateTest` (+9), `NumberFormatTest` (+6),
  `TieredBufferTest` (+10), `CircularBufferTest` (+10), `AxisRendererTest` (3),
  `LineSignalRendererTest` (2)

### API surface
- `chart-realtime.api`: 161 → 428 LOC
- `chart-realtime.klib.api`: 211 → 501 LOC

## [0.4.0] — 2026-05-21 — Portfolio Hardening

15 tasks shipped via 3-reviewer audit (android-reviewer + mobile-performance-reviewer +
mobile-architect). Library moved from "prototype" to "senior-engineer-built KMP library".

### Added
- LICENSE MIT
- `explicitApi() Strict` + Binary Compatibility Validator (BCV) 0.16.3 + klib enabled
- ABI baseline locked (`chart-realtime.api` 161 LOC, `chart-realtime.klib.api` 211 LOC)
- `hasData` boolean flag (replaces `POSITIVE_INFINITY` / `Float.MAX_VALUE` sentinels)
- `Snapshot.withMutableSnapshot` + `SnapshotApplyConflictException` retry helper
- M4 binning for Tier1/Tier2 (firstTs/V, minTs/V, maxTs/V, lastTs/V) with chronological dedup
- NaN/Inf/backward-timestamp guards on `push`; per-signal `lastPushedTs` tracking
- NumberFormat extracted from AxisRenderer (38 tests)
- 25 buffer/LoD tests (tier roll, window crossing, clear, LTTB branches)

### Changed
- `CircularBuffer.writeIndex` `Int` → `Long` (fixes 124d overflow @ 200Hz)
- `kotlinx-datetime` 0.6.2 replaces `expect/actual currentTimeMs` (Platform.kt deleted)
- `dataVersion` → `mutableLongStateOf` (Compose-observable, idle = 0 recompositions)
- Single `buffer.snapshot()` per signal per frame via per-signal scratch arrays
- `TIER1_CAPACITY` 12k → 24k, `TIER2_CAPACITY` 5.4k → 10.8k (×2 → ×4 for M4 binning)
- Memory per signal: ~760 KB → ~1.14 MB

### Removed
- `RenderLoop.kt`, `rememberFrameTick` (deleted)
- `maxBufferSeconds`, `xLabelDecimals`, `SignalConfig.label` (dead config)
- All `!!` and `@Suppress("UNUSED_EXPRESSION")` from commonMain

### Internal lockdown
- `CircularBuffer`, `TieredBuffer`, `LodDecimator`, `dataVersion`, `rememberFrameTick`,
  capacity constants

### Tests
- 33 → 107 (+74)

## [0.3.0] — 2026-05-21 — iOS Build Pipeline + Dirty Flag Render

### Added
- iOS targets compile + link green: `iosX64`, `iosArm64`, `iosSimulatorArm64`
- `applyDefaultHierarchyTemplate()` auto-wires `iosMain` / `iosTest`
- XCFramework `ChartRealtime` (debug + release): `ios-arm64` + `ios-arm64_x86_64-simulator`
- Dirty-flag render: `dataVersion` counter, skip Canvas draw when no new data
- `targetFps = 30` default in `ChartConfig` (null = max display refresh rate)
- iOS-side `Platform.ios.kt`: `NSDate()` + `timeIntervalSinceReferenceDate` + 1970 epoch
  offset (978_307_200s)
- KDoc on `RealtimeChart`, `RealtimeChartState`, `ChartConfig`, `LodMode`, `AxisLabelMode`
- README sections: LoD, AxisLabels, Material3

### Fixed
- Multiplatform replacements for JVM-only `String.format`: `formatFixed` /
  `formatScientific` / `pow10` helpers in `AxisRenderer`
- `kotlin.concurrent.Volatile` + `kotlin.jvm.JvmName` imports (OptionalExpectation)
- X axis: show negative values instead of clamping to `"0s"`

### Tests
- 17 → 33 (`RealtimeChartStateTest`: dataVersion + signal lifecycle)

## [0.2.0] — 2026-05-21 — Polish

### Added
- `TieredBuffer`: 3-tier ring buffer (5min full-rate, 10min @ 10Hz, 45min @ 1Hz),
  ~5MB footprint for 1h of data
- `LodMode.LTTB` (Largest-Triangle-Three-Buckets, O(n) decimation)
- `AxisLabelMode` (`INSIDE` / `BESIDE` / `HIDDEN`) with `chartLeft` / `chartBottom` insets
- `T0`-relative X-axis timestamps with mm:ss / hh:mm:ss formatting (negative supported)
- Material3 dynamic theming (light/dark, wallpaper-based, API 31+)
- Camera cutout / edge-to-edge support
- Sensor domain layer (Clean Architecture)
- Koin 4.0.0 DI wiring
- Sensor rate cap: 200Hz (5_000μs)

### Changed
- Package rename: `eu.henesis` → `dev.dtrentin`
- `TieredBuffer` binning: `MEAN` → `MIN_MAX` (composable across tier boundaries, no
  synthetic values, no C7 spike artifacts)
- `LodDecimator`: pre-allocated scratch arrays (zero GC at render time)

### Removed
- `LodMode.MEAN` (introduced synthetic values absent in raw signal)

## [0.1.0] — 2026-05-20 — MVP

Initial implementation. Six phases shipped:

1. Module scaffold (KMP + Compose Multiplatform + Android library)
2. `CircularBuffer` + `LodDecimator`
3. `RealtimeChartState` API
4. `RealtimeChart` composable + Canvas-based `SignalRenderer` + `AxisRenderer`
5. Demo app (`:app`)
6. Polish + initial docs

[Unreleased]: https://github.com/davide-trentin/KMPCharts/compare/v0.5.0...HEAD
[0.5.0]: https://github.com/davide-trentin/KMPCharts/releases/tag/v0.5.0
[0.4.0]: https://github.com/davide-trentin/KMPCharts/releases/tag/v0.4.0
[0.3.0]: https://github.com/davide-trentin/KMPCharts/releases/tag/v0.3.0
[0.2.0]: https://github.com/davide-trentin/KMPCharts/releases/tag/v0.2.0
[0.1.0]: https://github.com/davide-trentin/KMPCharts/releases/tag/v0.1.0