Skill: Dynamic Type Support

<!-- SEO: Dynamic Type accessibility font scaling UIFontMetrics fixed font size text clipping HIG typography iOS -->

Purpose

Detects fixed font sizes, fixed-height text containers, and Dynamic Type suppression patterns that prevent text from scaling with the user's preferred reading size, violating Apple's HIG Typography guidelines.

Apple Guideline

• Primary: HIG — Typography (Apple Human Interface Guidelines)
• Related: HIG — Accessibility
• Reference: references/hig/adaptive-layout.md

Real-World Rejection Cases

• Case: App with fixed font size 14 — text unreadable at large accessibility sizes Source: App Store Connect rejection feedback Root cause: All labels used .font(.system(size: 14)) with a hard-coded size instead of a semantic style like .font(.body) — fixed numeric sizes do not scale with the user's accessibility setting.

• Case: Fixed-height cell rows clipping text for users with large Dynamic Type Source: Apple Developer Forums Root cause: UITableViewCell height was hardcoded to 44 pt; at XXL accessibility size, label text overflowed the cell boundary and was clipped, causing a functional failure under HIG.

Trigger

Invoke on any iOS project that displays user-facing text to verify Dynamic Type is supported.

Inputs

Name	Type	Default	Description
project_root	path	cwd	iOS/macOS project root
shared_context	object	nil	Pre-collected context from appstore-full-audit Phase 1

Actions

Phase 1: Context Collection

Skip this phase if shared_context is provided.

1. Glob **/*.swift — collect Swift source files.
2. Glob **/*.m — collect Objective-C source files.
3. Glob **/*.storyboard and **/*.xib — note Interface Builder files where font and row-height properties may need manual review.

Phase 2: Checks

1. Fixed system font sizes (SwiftUI) Grep pattern \.font\(\.system\(size: in **/*.swift Every match using a numeric literal → 🟡 MEDIUM. In SwiftUI, replace with semantic styles: .font(.body), .font(.headline), .font(.caption) — these scale automatically with Dynamic Type. Do not add .dynamicTypeSize to a fixed-size font; that modifier constrains the size range, it does not make a hard-coded size scale. Do not use UIFontMetrics in SwiftUI; that is a UIKit class only.

2. Fixed-height text containers (SwiftUI) Grep pattern \.frame\(height: [0-9] in **/*.swift Inspect each match for proximity to a Text( view. A fixed numeric height wrapping a Text view will clip content at large Dynamic Type sizes → 🟡 MEDIUM.

3. Dynamic Type suppression Grep pattern minimumScaleFactor in **/*.swift and **/*.m A minimumScaleFactor less than 1.0 causes text to shrink rather than reflow, suppressing Dynamic Type intent → 🟡 MEDIUM. Flag all occurrences for review.

4. UIKit fixed font without UIFontMetrics Grep pattern UIFont\.systemFont\(ofSize: in **/*.swift and **/*.m Any call not followed by a UIFontMetrics scaling call → 🟡 MEDIUM. The correct pattern is UIFontMetrics.default.scaledFont(for:).

Phase 3: Output

Collect all findings from Phase 2 and build the prioritised findings list below. Include file paths and line numbers. Omit tiers with no findings.

Output Format

## Dynamic Type Support — Findings

### 🔴 CRITICAL — Guaranteed rejection
- [ ] TODO: <exact actionable step> — `file:line` — HIG Typography

### 🟠 HIGH — Very likely rejection
- [ ] TODO: <exact actionable step> — `file:line` — HIG Typography

### 🟡 MEDIUM — Possible rejection
- [ ] TODO: <exact actionable step> — `file:line`

### 🟢 LOW — Best practice
- [ ] TODO: <exact actionable step>

Tools Used

Glob, Grep, Read

Constraints

• Read-only. No file edits.
• No network calls.
• Skip Phase 1 if shared_context is provided by orchestrating agent.
• Works on Swift, Objective-C, React Native, Flutter projects.

Quick Commands

Run these in your project root to check manually:

# Find fixed font sizes not using UIFontMetrics
!grep -rn "\.system(size:\|systemFont(ofSize:" . --include="*.swift" | grep -v "UIFontMetrics\|scaledFont"

# Find fixed-height containers wrapping text
!grep -rn "\.frame(height:" . --include="*.swift"

Swift Anti-Pattern Reference

examples/swift/LayoutPatterns.swift

Detection Steps

1. Find target files

   • Glob: **/*.swift, **/*.m

2. Search for rejection patterns (two-pass approach required)

   • Pass A — Grep \.systemFont(ofSize: → collect all matches
   • Pass B — Grep UIFontMetrics in the same files; lines not covered by Pass B are fixed-size fonts
   • Grep UIFont(name: → custom font; check same file for UIFontMetrics.default.scaledFont or scaledFont(for:
   • Grep heightAnchor\.constant =\|frame\.size\.height = — fixed-height containers (manual check: is the container holding a label?)
   • Grep numberOfLines = 1 — single-line labels (verify surrounding context for adjustsFontSizeToFitWidth)

3. Determine verdict

   • Fixed font size on a visible label (not icon/decoration) → 🟡 MEDIUM
   • Fixed-height container clipping label text → 🟡 MEDIUM
   • UIFontMetrics or SwiftUI semantic fonts (.body, .headline) used → 🟢 pass

4. Report

   • File path + line of fixed-size font usage
   • Fix: Wrap custom fonts with UIFontMetrics(forTextStyle: .body).scaledFont(for: font); use adjustsFontForContentSizeCategory = true on labels