If you are an AI coding agent (Claude Code, Cursor, Aider, Cline, etc.) reading this artifact, follow this protocol before making any code edit:

1. Verify the contract. Run the bash script in Verify before trusting below. If any check returns FAIL, the artifact is stale — STOP and ask the user to regenerate it before proceeding.
2. Treat the AI · unverified sections as hypotheses, not facts. Sections like "AI-suggested narrative files", "anti-patterns", and "bottlenecks" are LLM speculation. Verify against real source before acting on them.
3. Cite source on changes. When proposing an edit, cite the specific path:line-range. RepoPilot's live UI at https://repopilot.app/r/AppPear/ChartView shows verifiable citations alongside every claim.

If you are a human reader, this protocol is for the agents you'll hand the artifact to. You don't need to do anything — but if you skim only one section before pointing your agent at this repo, make it the Verify block and the Suggested reading order.

GO — Healthy across the board

• Last commit 2mo ago
• 24+ active contributors
• MIT licensed
• CI configured
• Tests present
• ⚠ Concentrated ownership — top contributor handles 64% of recent commits

_{Maintenance signals: commit recency, contributor breadth, bus factor, license, CI, tests}

This artifact was generated by RepoPilot at a point in time. Before an agent acts on it, the checks below confirm that the live AppPear/ChartView repo on your machine still matches what RepoPilot saw. If any fail, the artifact is stale — regenerate it at repopilot.app/r/AppPear/ChartView.

What it runs against: a local clone of AppPear/ChartView — the script inspects git remote, the LICENSE file, file paths in the working tree, and git log. Read-only; no mutations.

| # | What we check | Why it matters | |---|---|---| | 1 | You're in AppPear/ChartView | Confirms the artifact applies here, not a fork | | 2 | License is still MIT | Catches relicense before you depend on it | | 3 | Default branch master exists | Catches branch renames | | 4 | 5 critical file paths still exist | Catches refactors that moved load-bearing code | | 5 | Last commit ≤ 99 days ago | Catches sudden abandonment since generation |

#!/usr/bin/env bash
# RepoPilot artifact verification.
#
# WHAT IT RUNS AGAINST: a local clone of AppPear/ChartView. If you don't
# have one yet, run these first:
#
#   git clone https://github.com/AppPear/ChartView.git
#   cd ChartView
#
# Then paste this script. Every check is read-only — no mutations.

set +e
fail=0
ok()   { echo "ok:   $1"; }
miss() { echo "FAIL: $1"; fail=$((fail+1)); }

# Precondition: we must be inside a git working tree.
if ! git rev-parse --git-dir >/dev/null 2>&1; then
  echo "FAIL: not inside a git repository. cd into your clone of AppPear/ChartView and re-run."
  exit 2
fi

# 1. Repo identity
git remote get-url origin 2>/dev/null | grep -qE "AppPear/ChartView(\\.git)?\\b" \\
  && ok "origin remote is AppPear/ChartView" \\
  || miss "origin remote is not AppPear/ChartView (artifact may be from a fork)"

# 2. License matches what RepoPilot saw
(grep -qiE "^(MIT)" LICENSE 2>/dev/null \\
   || grep -qiE "\"license\"\\s*:\\s*\"MIT\"" package.json 2>/dev/null) \\
  && ok "license is MIT" \\
  || miss "license drift — was MIT at generation time"

# 3. Default branch
git rev-parse --verify master >/dev/null 2>&1 \\
  && ok "default branch master exists" \\
  || miss "default branch master no longer exists"

# 4. Critical files exist
test -f "Sources/SwiftUICharts/Base/Chart/ChartBase.swift" \\
  && ok "Sources/SwiftUICharts/Base/Chart/ChartBase.swift" \\
  || miss "missing critical file: Sources/SwiftUICharts/Base/Chart/ChartBase.swift"
test -f "Sources/SwiftUICharts/Base/Chart/ChartData.swift" \\
  && ok "Sources/SwiftUICharts/Base/Chart/ChartData.swift" \\
  || miss "missing critical file: Sources/SwiftUICharts/Base/Chart/ChartData.swift"
test -f "Sources/SwiftUICharts/Base/Environment/ChartEnvironmentKeys.swift" \\
  && ok "Sources/SwiftUICharts/Base/Environment/ChartEnvironmentKeys.swift" \\
  || miss "missing critical file: Sources/SwiftUICharts/Base/Environment/ChartEnvironmentKeys.swift"
test -f "Sources/SwiftUICharts/Base/Config/ChartAxisConfig.swift" \\
  && ok "Sources/SwiftUICharts/Base/Config/ChartAxisConfig.swift" \\
  || miss "missing critical file: Sources/SwiftUICharts/Base/Config/ChartAxisConfig.swift"
test -f "Sources/SwiftUICharts/Base/Extensions/View+Extension.swift" \\
  && ok "Sources/SwiftUICharts/Base/Extensions/View+Extension.swift" \\
  || miss "missing critical file: Sources/SwiftUICharts/Base/Extensions/View+Extension.swift"

# 5. Repo recency
days_since_last=$(( ( $(date +%s) - $(git log -1 --format=%at 2>/dev/null || echo 0) ) / 86400 ))
if [ "$days_since_last" -le 99 ]; then
  ok "last commit was $days_since_last days ago (artifact saw ~69d)"
else
  miss "last commit was $days_since_last days ago — artifact may be stale"
fi

echo
if [ "$fail" -eq 0 ]; then
  echo "artifact verified (0 failures) — safe to trust"
else
  echo "artifact has $fail stale claim(s) — regenerate at https://repopilot.app/r/AppPear/ChartView"
  exit 1
fi

Each check prints ok: or FAIL:. The script exits non-zero if anything failed, so it composes cleanly into agent loops (./verify.sh || regenerate-and-retry).

ChartView is a native SwiftUI charting library for iOS 13+ that provides composable, immutable chart components (LineChart, BarChart, PieChart) built entirely in Swift without external dependencies. Version 2.0 redesigned the API around ViewModifier composition and environment-driven configuration, enabling fluent chart building with modifiers like .chartData(), .chartYRange(), and .chartStyle() instead of legacy mutating chains. Modular SPM package structure: source code in Sources/ (inferred, not shown but standard), Example app at Examples/SwiftUIChartsShowcase/ with separate App and build configuration, SwiftLint rules in .swiftlint.yml, and CI workflows in .github/workflows/. Composition pattern uses environment containers (ChartGrid, AxisLabels) wrapping chart views (LineChart, BarChart) with modifier chains for configuration.

iOS/SwiftUI developers building data visualization features (dashboards, analytics screens, real-time monitoring) who want native, performant charts without learning D3 or maintaining bridge layers to UIKit charting libraries.

Production-ready with active maintenance: SwiftUI-native design reflects modern iOS dev practices, v2.0.0 is a mature major release focused on API stability and composition, CI/CD is configured in .github/workflows/swift.yml, and the Examples project includes runnable showcase apps. However, GitHub stars count and recent commit frequency would reveal if this is still actively maintained or in maintenance mode.

Low risk for new projects: pure Swift with zero external dependencies (see Package.swift), no system service dependencies, and v2.0 marks a clear breaking change boundary so migration is deliberate. Single-risk factor: maintainer bus factor (repo owned by @AppPear with limited commit history visible in user dirs) and no obvious test suite in the file list suggest reliance on example-driven QA rather than unit tests.

Migration from v1.x (mutating API) to v2.0.0 (immutable ViewModifier-based API) is the primary work. Evidence: v2Ticket template in ISSUE_TEMPLATE, MIGRATION.md file present, and README spotlights 2.0.0 as 'major release focused on immutable configuration.' Pull request template exists for structured contributions.

Check README for instructions.

Daily commands: For library: build with xcodebuild build -scheme ChartView (SPM). For showcase app: xcodebuild -project Examples/SwiftUIChartsShowcase/SwiftUIChartsShowcase.xcodeproj -scheme SwiftUIChartsShowcase -configuration Debug. Or open .swiftpm/xcode/package.xcworkspace in Xcode and hit Run.

• Sources/SwiftUICharts/Base/Chart/ChartBase.swift — Core chart abstraction layer defining the base protocol and container for all chart types; every chart implementation depends on this
• Sources/SwiftUICharts/Base/Chart/ChartData.swift — Data model contract for chart inputs; defines how data flows into charts and must be understood for proper data binding
• Sources/SwiftUICharts/Base/Environment/ChartEnvironmentKeys.swift — Central registry of SwiftUI environment modifiers for chart configuration; understanding this is critical for adding new chart properties
• Sources/SwiftUICharts/Base/Config/ChartAxisConfig.swift — Axis configuration model that drives labels, ranges, and tick behavior across all chart types
• Sources/SwiftUICharts/Base/Extensions/View+Extension.swift — Implements the modifier-based API surface (chartData, chartStyle, chartXRange, etc.) that users interact with
• Package.swift — Swift Package Manager manifest defining library targets, dependencies, and supported platforms
• README.md — Documents v2.x API contract and composable design philosophy; required reading before contributing

Add a new chart type (e.g., ScatterPlotChart)

1. Create a new View struct conforming to ChartBase protocol in Sources/SwiftUICharts/Base/Chart/ (Sources/SwiftUICharts/Base/Chart/ScatterPlotChart.swift)
2. Implement body property to compose ChartBase with custom rendering shapes; use @Environment to read axis config, grid config, and series styling (Sources/SwiftUICharts/Base/Chart/ScatterPlotChart.swift)
3. Add a public convenience initializer accepting ChartData in Sources/SwiftUICharts/Base/Extensions/View+Extension.swift as a new modifier func (e.g., scatterPlotChart(_:)) (Sources/SwiftUICharts/Base/Extensions/View+Extension.swift)
4. If chart type requires custom axis behavior, extend ChartAxisConfig in Sources/SwiftUICharts/Base/Config/ChartAxisConfig.swift with computed properties (Sources/SwiftUICharts/Base/Config/ChartAxisConfig.swift)
5. Test by adding usage example in Examples/SwiftUIChartsShowcase/SwiftUIChartsShowcaseApp/ and verify with included showcase app (Examples/SwiftUIChartsShowcase/SwiftUIChartsShowcaseApp/ShowcaseHomeView.swift)

Add a new chart configuration property (e.g., shadow effect)

1. Define a new configuration struct (e.g., ChartShadowConfig) in Sources/SwiftUICharts/Base/Config/ (Sources/SwiftUICharts/Base/Config/ChartShadowConfig.swift)
2. Register a new environment key in Sources/SwiftUICharts/Base/Environment/ChartEnvironmentKeys.swift following the existing pattern (Sources/SwiftUICharts/Base/Environment/ChartEnvironmentKeys.swift)
3. Add a public modifier function in Sources/SwiftUICharts/Base/Extensions/View+Extension.swift (e.g., chartShadow(_:)) (Sources/SwiftUICharts/Base/Extensions/View+Extension.swift)
4. In chart implementations (ChartBase implementations), read the environment key using @Environment and apply shadow effect in rendering (Sources/SwiftUICharts/Base/Chart/ChartBase.swift)

Implement automatic axis label generation from data range

1. Extend the AxisLabelsData model in Sources/SwiftUICharts/Base/Axis/Model/AxisLablesData.swift with auto-generation logic (Sources/SwiftUICharts/Base/Axis/Model/AxisLablesData.swift)
2. Add helper methods in Array+Extension.swift for finding nice tick values (e.g., decimalPlaces rounding, step calculation) (Sources/SwiftUICharts/Base/Extensions/Array+Extension.swift)
3. Add a chartXAxisAutoTicks() and chartYAxisAutoTicks() modifier in View+Extension.swift that compute labels from data range via environment (Sources/SwiftUICharts/Base/Extensions/View+Extension.swift)
4. Update AxisLabels.swift to read generated labels from environment and render them (Sources/SwiftUICharts/Base/Axis/AxisLabels.swift)

Add live streaming data support to an existing chart

1. Ensure chart type accepts ChartStreamingDataSource in addition to static ChartData (Sources/SwiftUICharts/Base/Chart/ChartStreamingDataSource.swift)
2. Add @State or @ObservedObject property in chart View to subscribe to streaming updates (Sources/SwiftUICharts/Base/Chart/ChartBase.swift)
3. Optionally apply ChartDownsampler in view body to limit rendered points for performance (Sources/SwiftUICharts/Base/Chart/ChartDownsampler.swift)
4. Add chartPerformanceConfig() modifier to allow tuning downsampling threshold (Sources/SwiftUICharts/Base/Config/ChartPerformanceConfig.swift)

No environment variables or runtime services required. Key gotcha: v1.x and v2.0 APIs are incompatible — old code using .data(...) or .rangeX(...) will not compile. Mixing old and new modifiers will fail. SwiftUI layout behavior with frame() sizing chart containers can be unintuitive; see Examples project for working frame height/padding patterns. No explicit documentation on streaming data performance limits or dataset size thresholds mentioned in 'chartPerformance(...)' modifier.

• ViewModifier composition — v2.0 API is entirely modifier-based (.chartData(), .chartStyle(), .chartYRange()); understanding fluent builder patterns is essential to using this library correctly
• SwiftUI Environment — Chart configuration (grid lines, axis labels, colors) propagates via @Environment; modifying environment state without rebuilding containers breaks composition
• Categorical vs. continuous domain — API contract distinguishes chartData([Double]) (categorical: bar chart slots) from chartData([(Double, Double)]) (continuous: line chart X/Y pairs); semantic mismatch causes scaling bugs
• Canvas and Shape rendering — ChartView likely uses SwiftUI Canvas (iOS 15+) or custom Shape drawing for performance; understanding GPU vs. software rendering tradeoffs matters for streaming data
• Color gradient interpolation — ColorGradient modifier handles smooth color transitions across chart values; interpolation quality affects visual polish on large datasets
• Immutable data flow — v2.0 explicitly rejects mutating chains in favor of pure functional composition; enables predictable re-renders and SwiftUI diffing

• danielgindi/Charts — Mature, widely-used iOS charting library (MPAndroidChart port); gold standard for comparison but UIKit-based so requires bridging for SwiftUI
• airbnb/lottie-ios — Complementary SwiftUI animation library; many chart dashboards layer Lottie overlays for transitions that ChartView doesn't natively provide
• pointfreeco/swift-composable-architecture — State management pattern often paired with ChartView in production apps; demonstrates immutable data flow that aligns with v2.0's philosophy
• SwiftUIX/SwiftUIX — Broader SwiftUI component library that includes chart utilities; users migrating from older charting libs often discover cross-compatible modifiers here
• apple/swift-numerics — Official Swift numeric algorithms; ChartView could leverage for interpolation and curve smoothing (currently appears custom-implemented)

To work on one of these in Claude Code or Cursor, paste: Implement the "<title>" PR idea from CLAUDE.md, working through the checklist as the task list.

Add unit tests for AxisLabels.swift and AxisLabelsPosition.swift

The Axis subsystem in Sources/SwiftUICharts/Base/Axis/ lacks test coverage. Given that axis labeling is critical for chart readability and the 2.0.0 release emphasizes immutable configuration, adding tests for label positioning logic, range calculations, and edge cases (empty data, single values, extreme ranges) would prevent regressions and document expected behavior.

• [ ] Create Tests/SwiftUIChartsTests/Base/Axis/ directory structure
• [ ] Add unit tests for AxisLabels.swift covering label generation, formatting, and positioning logic
• [ ] Add unit tests for AxisLabelsPosition.swift covering all position enum cases and their layout calculations
• [ ] Integrate tests into .github/workflows/swift.yml CI pipeline
• [ ] Document test patterns in CONTRIBUTING.md or similar for future contributors

Add GitHub Action workflow for SwiftLint enforcement

.swiftlint.yml exists in the repo but the CI workflow (.github/workflows/swift.yml) likely doesn't run SwiftLint checks. This means code style violations can slip into PRs. Adding a dedicated SwiftLint check action would enforce the existing style guide and maintain consistency across the 2.0.0 composable API surface.

• [ ] Review current .github/workflows/swift.yml to confirm SwiftLint is not executed
• [ ] Create new workflow file .github/workflows/swiftlint.yml using a SwiftLint GitHub Action
• [ ] Configure action to fail PR checks if style violations exceed thresholds defined in .swiftlint.yml
• [ ] Test workflow locally with a sample style violation to ensure it catches issues
• [ ] Update CONTRIBUTING.md with instruction to run swiftlint locally before submitting PRs

Document the 2.0.0 API contract with runnable examples in Examples/SwiftUIChartsShowcase

The README contains an 'AI Agent Quick Context' section documenting the 2.x API contract (chartData, chartXRange, chartYRange, chartStyle, chartGridLines modifiers), but Examples/SwiftUIChartsShowcase lacks concrete showcase views demonstrating each modifier in isolation. New contributors need runnable reference code to understand how to compose charts correctly per the new immutable API.

• [ ] Add ShowcaseModifierExamplesView.swift demonstrating individual modifiers: chartData(), chartXRange(), chartYRange(), chartStyle()
• [ ] Add ShowcaseDataSemanticsView.swift with side-by-side examples of categorical (chartData([Double])) vs continuous (chartData([(Double, Double)])) data sources
• [ ] Add comments to Examples/SwiftUIChartsShowcaseApp/ShowcaseHomeView.swift linking new examples and explaining when to use each API pattern
• [ ] Include comments in showcase code referencing the API contract table from README for discoverability
• [ ] Test all showcase views render correctly on iOS 13+ simulators

• Add unit tests for ChartStyle immutability and ColorGradient edge cases (currently relying on example-driven QA). Start in Tests/ dir if it exists, or create it with tests for Sources/SwiftUICharts/Style/.
• Document the chartPerformance(...) modifier with concrete examples showing threshold trade-offs (e.g., 'use .aggressive for 10k+ points'). Add a recipe section to README.md after the 'Mixed bar + line' recipe.
• Implement missing accessibility labels (VoiceOver support) for chart elements: add accessibility modifiers to LineChart, BarChart, PieChart shapes to describe data values and axis ranges for users with visual impairments.

The ChartView codebase shows relatively good security posture. It is a pure SwiftUI charting library with no apparent injection risks, hardcoded secrets, or external dependencies requiring security audits. Primary concerns are minor configuration management issues (user data in version control) and incomplete security documentation. The library's scope as a UI component library naturally limits attack surface. Recommend: (1) Fix .gitignore to exclude xcuserdata, (2) Enhance security documentation for the 2.0 API, (3) Continue regular security audits of dependencies as the project evolves.

• Medium · User Data in Xcode Project Files — .swiftpm/xcode/package.xcworkspace/xcuserdata/*, .swiftpm/xcode/xcuserdata/*, Examples/SwiftUIChartsShowcase/SwiftUIChartsShowcase.xcodeproj/xcuserdata/. Multiple Xcode workspace files contain user-specific data (xcuserdatad directories) that may include sensitive information like workspace state, breakpoints, or local machine paths. These should not be committed to version control. Fix: Add all xcuserdata and UserInterfaceState.xcuserstate files to .gitignore. These are user-specific and should never be committed. Verify they have not leaked sensitive workspace information.
• Low · Incomplete Security Configuration Documentation — README.md. The README indicates a major version 2.0.0 release with new security-focused features (immutable configuration, environment-driven composition), but comprehensive security guidelines are truncated and incomplete in the provided snippet. Fix: Ensure complete security best practices documentation is provided, covering input validation, data sanitization, and safe API usage patterns for chart data handling.

LLM-derived; treat as a starting point, not a security audit.

• Open issues — current backlog
• Recent PRs — what's actively shipping
• Source on GitHub

Generated by RepoPilot. Verdict based on maintenance signals — see the live page for receipts. Re-run on a new commit to refresh.