Swift Charts

Declarative data visualization for Apple platforms. The deep API reference — every 2D mark type, plottable values, styling, axis/scale customization, legends and annotations, interactivity, and the iOS 26 Chart3D/SurfacePlot story — lives in references/guide.md. This file is the decision and discipline layer: read it first, open the guide for specifics. For everything around the chart (layout, state, navigation, view composition), use swiftui-pro.

Dials

Set these explicitly at the start; they change what "correct" means.

1. MARK — the primitive that matches the data's meaning: bar (category comparison) · line/area (trend over time) · point (distribution/correlation) · sector (part-of-whole pie/donut) · rule/rectangle (reference lines, heatmaps). Pick by data shape, not by what looks nice.
2. SERIES — single (one mark, one color) · grouped (multiple categories distinguished by .foregroundStyle(by:), optionally .position(by:) for side-by-side) · stacked (same with stacking, the default for repeated x). Driving color by value is what generates the legend.
3. INTERACTION — static (display only) · selection (.chartXSelection/.chartYSelection/.chartAngleSelection, iOS 17+) · scrolling (.chartScrollableAxes + .chartXVisibleDomain, iOS 17+). Don't reach for raw gestures when a selection modifier exists.

When to use

Building or reviewing any chart, graph, plot, or data-visualization view that uses the Charts framework — marks, axes, scales, legends, selection, scrolling, or 3D. If the work is general SwiftUI (layout, navigation, @State, view modeling) with no Charts import, use swiftui-pro.

Core rules