drafter

feat: chart interactivity, robustness, full API docs, and DrafterLege…

Added

• Interactivity — a new InteractiveChart wrapper turns any chart into a touch/mouse-driven one: a trackball with a de-overlapping multi-series tooltip, tap value-selection, and drag range-selection, all painted on a non-rebuilding Canvas overlay so the base chart's reveal animation is never disturbed. Works across every chart type — cartesian charts (line/area/step/bar/candlestick/ stream) get a trackball-column tooltip + range band; radial and free-layout charts (pie/donut/polar/sunburst/treemap/heatmap/funnel/bullet/box-plot/bubble/ gantt/sankey/scatter/radar) get per-mark hover highlighting.
• ChartInteraction config — independently toggle tooltip, selection and rangeSelection, with onSelected / onRangeSelected callbacks and a custom rowLabel tooltip formatter.
• Public interaction model — ChartScene, PlotMark, ChartSelection, ChartRange (from package:drafter/drafter.dart) and the pure ChartHitTest / LabelLayout helpers (from package:drafter/painting.dart), so you can hit-test custom charts. Renderers opt in via the InteractiveRenderer interface and a buildScene(Size) derived from the same math they paint with.
• CartesianScale — a reversible data↔pixel mapping shared by paint and hit-test, so the two can never drift.
• Every chart widget (and InteractiveChart) now exposes a duration parameter to tune the entrance-animation length.
• ChartRenderer / InteractiveRenderer are now re-exported from the main package:drafter/drafter.dart entrypoint (they appear in InteractiveChart's signature).
• DrafterLegend — a reusable, theme-aware legend widget. Build it from explicit LegendItems or from a list of labels (DrafterLegend.fromLabels, which colors each entry by the active theme palette). Supports horizontal (wrapping) or vertical layout, square / circle / line markers, and an optional onItemTap callback for wiring series toggling.

Fixed

• Robustness — non-finite (NaN / Infinity) input values are now coerced at ingestion across all value-based charts, so malformed data can no longer produce a non-finite Canvas coordinate (a debug assert) or reach a toInt() (which threw UnsupportedError even in release builds — histogram binning, bubble axis rounding, line/bar axis steps).
• InteractiveChart resets its interaction state when its renderer changes, so a stale selection highlight can't linger over new data, and it no longer writes to its disposed notifier if the pointer exits during teardown.

Performance

• The interaction overlay only repaints when the resolved hover/selection state actually changes (value-equal snapshots), is isolated in its own RepaintBoundary, and hit-tests by squared distance.
• Layout-heavy renderers (heatmap, treemap, sankey, candlestick moving-averages) memoize their progress-independent layout per size instead of recomputing it on every animation frame; candlestick moving averages now use an O(n) sliding window.

Documentation

• The full public API is now documented (every constructor, field and getter), enforced by enabling public_member_api_docs in the analyzer.

Added

• ScatterPlot.values(values: [(x, y), …]) — a values-first convenience constructor matching the line/area/bar charts.
• package:drafter/painting.dart — a dedicated entrypoint for the chart-authoring extension API (ChartRenderer, ChartCanvas, layout math, smooth-graphics helpers), keeping the main drafter.dart namespace focused on charts/data/theme.

Changed (breaking)

• The low-level drawing/layout helpers (smoothPath, trimPath, drawChartText, ChartBounds, RadialLayout, HAlign/VAlign, etc.) are no longer exported from package:drafter/drafter.dart — import package:drafter/painting.dart instead. The everyday chart widgets, data models and theming are unchanged.

Fixed

• BubbleChart no longer crashes (debug assert via a non-finite Offset) when every bubble shares a zero on an axis.
• DrafterThemeColors ==/hashCode now include the palette, so a palette-only theme change correctly repaints the charts.
• colorAt falls back instead of throwing on an empty palette.
• ChartCanvas now picks up a changed duration on rebuild.

Performance

• Static label text is cached (TextPainters are no longer re-shaped every animation frame), the painter repaints off the animation listenable inside a RepaintBoundary, line charts compute path metrics once per frame instead of twice, and the stream graph no longer builds its top spline twice per band.

Initial release — a premium, dependency-free Flutter charting library, a faithful port of the Compose/SwiftUI Drafter charts.

• ~27 chart types across one shared core: line, grouped line, stacked line, area, step line, simple/grouped/stacked bar, histogram, waterfall, pie, donut, radar, polar area, gauge, scatter, bubble, heatmap, funnel, bullet, box plot, treemap, sunburst, sankey, gantt, stream graph and candlestick.
• Renderer architecture: every chart is a pure ChartRenderer drawing into a Canvas, hosted by a thin widget over shared data models, axis/radial math, Catmull-Rom smooth graphics and a left-to-right reveal animation.
• DrafterTheme / DrafterThemeColors for light/dark palettes — a calm, premium color set (no harsh red).
• Built-in semantics: each chart exposes an accessibility label and value.