accessibility-patterns

Accessibility Patterns — Expert Decisions

Expert decision frameworks for accessibility choices. Claude knows accessibilityLabel and VoiceOver — this skill provides judgment calls for element grouping, label strategies, and compliance trade-offs.

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Decision Trees

Element Grouping Strategy

How should VoiceOver read this content?
├─ Logically related (card, cell, profile)
│  └─ Combine: .accessibilityElement(children: .combine)
│     Read as single unit
│
├─ Each part independently actionable
│  └─ Keep separate
│     User needs to interact with each
│
├─ Container with multiple actions
│  └─ Combine + custom actions
│     Single element with .accessibilityAction
│
├─ Decorative image with text
│  └─ Combine, image hidden
│     Image adds no meaning
│
└─ Image conveys different info than text
   └─ Keep separate with distinct labels
      Both need to be announced

The trap: Combining elements that have different actions. User can't interact with individual parts.

Label vs Hint Decision

What should be in label vs hint?
├─ What the element IS
│  └─ Label
│     "Play button", "Submit form"
│
├─ What happens when activated
│  └─ Hint (only if not obvious)
│     "Double tap to start playback"
│
├─ Current state
│  └─ Value
│     "50 percent", "Page 3 of 10"
│
└─ Control behavior
   └─ Traits
      .isButton, .isSelected, .isHeader

Dynamic Type Layout Strategy

How should layout adapt to larger text?
├─ Simple HStack (icon + text)
│  └─ Stay horizontal
│     Icons scale with text
│
├─ Complex HStack (image + multi-line)
│  └─ Stack vertically at xxxLarge
│     Check @Environment(\.dynamicTypeSize)
│
├─ Fixed-height cells
│  └─ Self-sizing
│     Remove height constraints
│
└─ Toolbar/navigation elements
   └─ Consider overflow menu
      Or scroll at extreme sizes

Reduce Motion Response

What happens when Reduce Motion is enabled?
├─ Transition between screens
│  └─ Instant or simple fade
│     No slide/zoom animations
│
├─ Loading indicators
│  └─ Static or minimal
│     No bouncing/spinning
│
├─ Autoplay video/animation
│  └─ Don't autoplay
│     User controls playback
│
├─ Parallax/motion effects
│  └─ Disable completely
│     Can cause vestibular issues
│
└─ Essential animation (progress)
   └─ Keep but simplify
      Linear, no bounce

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NEVER Do

VoiceOver Labels

NEVER include element type in labels:

// ❌ Redundant — VoiceOver announces "Submit button, button"
Button("Submit") { }
    .accessibilityLabel("Submit button")

// ✅ VoiceOver announces "Submit, button"
Button("Submit") { }
    .accessibilityLabel("Submit")

// ❌ Redundant — "Profile image, image"
Image("profile")
    .accessibilityLabel("Profile image")

// ✅ Describe what the image shows
Image("profile")
    .accessibilityLabel("John Doe's profile photo")

NEVER use generic labels:

// ❌ User has no idea what this does
Button(action: deleteItem) {
    Image(systemName: "trash")
}
.accessibilityLabel("Button")

// ❌ Still not helpful
Button(action: deleteItem) {
    Image(systemName: "trash")
}
.accessibilityLabel("Icon")

// ✅ Describe the action
Button(action: deleteItem) {
    Image(systemName: "trash")
}
.accessibilityLabel("Delete \(item.name)")

NEVER forget to label icon-only buttons:

// ❌ VoiceOver says nothing useful
Button(action: share) {
    Image(systemName: "square.and.arrow.up")
}
// VoiceOver: "Button" (no label!)

// ✅ Always label icon buttons
Button(action: share) {
    Image(systemName: "square.and.arrow.up")
}
.accessibilityLabel("Share")

Element Visibility

NEVER hide interactive elements from accessibility:

// ❌ User can't access this control
Button("Settings") { }
    .accessibilityHidden(true)  // Why would you do this?

// ✅ Every interactive element must be accessible
// Only hide truly decorative elements
Image("decorative-pattern")
    .accessibilityHidden(true)  // This is OK — adds nothing

NEVER leave decorative images accessible:

// ❌ VoiceOver reads meaningless "image"
Image("background-gradient")
// VoiceOver: "Image"

// ✅ Hide decorative elements
Image("background-gradient")
    .accessibilityHidden(true)

Dynamic Type

NEVER use fixed font sizes for user content:

// ❌ Doesn't respect user's text size preference
Text("Hello, World!")
    .font(.system(size: 16))  // Never scales!

// ✅ Use Dynamic Type styles
Text("Hello, World!")
    .font(.body)  // Scales automatically

// ✅ Custom font with scaling
Text("Custom")
    .font(.custom("MyFont", size: 16, relativeTo: .body))

NEVER truncate text at larger sizes without alternative:

// ❌ Content disappears at larger text sizes
Text(longContent)
    .lineLimit(2)
    .font(.body)
// At xxxLarge, user sees "Lorem ips..."

// ✅ Allow expansion or provide full content path
Text(longContent)
    .lineLimit(dynamicTypeSize >= .xxxLarge ? nil : 2)
    .font(.body)

// Or use "Read more" expansion

Reduce Motion

NEVER ignore reduce motion for essential navigation:

// ❌ User with vestibular disorders feels sick
.transition(.slide)
// Reduce Motion enabled, but still slides

// ✅ Respect reduce motion
@Environment(\.accessibilityReduceMotion) var reduceMotion

.transition(reduceMotion ? .opacity : .slide)

NEVER autoplay video when reduce motion is enabled:

// ❌ Autoplay ignores user preference
VideoPlayer(player: player)
    .onAppear { player.play() }  // Always autoplays

// ✅ Check reduce motion
VideoPlayer(player: player)
    .onAppear {
        if !UIAccessibility.isReduceMotionEnabled {
            player.play()
        }
    }

Color and Contrast

NEVER convey information by color alone:

// ❌ Color-blind users can't distinguish states
Circle()
    .fill(isOnline ? .green : .red)  // Only color differs

// ✅ Use shape/icon in addition to color
HStack {
    Circle()
        .fill(isOnline ? .green : .red)
    Text(isOnline ? "Online" : "Offline")
}
// Or
Image(systemName: isOnline ? "checkmark.circle.fill" : "xmark.circle.fill")
    .foregroundColor(isOnline ? .green : .red)

---

Essential Patterns

Accessible Card Component

struct AccessibleCard: View {
    let item: Item
    let onTap: () -> Void
    let onDelete: () -> Void
    let onShare: () -> Void

    var body: some View {
        VStack(alignment: .leading, spacing: 8) {
            Text(item.title)
                .font(.headline)

            Text(item.description)
                .font(.body)
                .foregroundColor(.secondary)

            Text(item.date, style: .date)
                .font(.caption)
        }
        .padding()
        .background(Color(.systemBackground))
        .cornerRadius(12)

        // Combine all text for VoiceOver
        .accessibilityElement(children: .combine)
        .accessibilityLabel("\(item.title). \(item.description). \(item.date.formatted())")
        .accessibilityAddTraits(.isButton)

        // Custom actions instead of hidden buttons
        .accessibilityAction(.default) { onTap() }
        .accessibilityAction(named: "Delete") { onDelete() }
        .accessibilityAction(named: "Share") { onShare() }
    }
}

Dynamic Type Adaptive Layout

struct AdaptiveProfileView: View {
    @Environment(\.dynamicTypeSize) private var dynamicTypeSize

    let user: User

    var body: some View {
        if dynamicTypeSize.isAccessibilitySize {
            // Vertical layout for accessibility sizes
            VStack(alignment: .leading, spacing: 12) {
                profileImage
                userInfo
            }
        } else {
            // Horizontal layout for standard sizes
            HStack(spacing: 16) {
                profileImage
                userInfo
            }
        }
    }

    private var profileImage: some View {
        Image(user.avatarName)
            .resizable()
            .scaledToFill()
            .frame(width: imageSize, height: imageSize)
            .clipShape(Circle())
            .accessibilityLabel("\(user.name)'s profile photo")
    }

    private var userInfo: some View {
        VStack(alignment: .leading, spacing: 4) {
            Text(user.name)
                .font(.headline)
            Text(user.title)
                .font(.subheadline)
                .foregroundColor(.secondary)
        }
    }

    private var imageSize: CGFloat {
        dynamicTypeSize.isAccessibilitySize ? 80 : 60
    }
}

extension DynamicTypeSize {
    var isAccessibilitySize: Bool {
        self >= .accessibility1
    }
}

Reduce Motion Wrapper

struct MotionSafeAnimation<Content: View>: View {
    @Environment(\.accessibilityReduceMotion) private var reduceMotion

    let fullAnimation: Animation
    let reducedAnimation: Animation
    let content: Content

    init(
        full: Animation = .spring(),
        reduced: Animation = .linear(duration: 0.2),
        @ViewBuilder content: () -> Content
    ) {
        self.fullAnimation = full
        self.reducedAnimation = reduced
        self.content = content()
    }

    var body: some View {
        content
            .animation(reduceMotion ? reducedAnimation : fullAnimation, value: UUID())
    }
}

// Usage
struct AnimatedButton: View {
    @State private var isPressed = false
    @Environment(\.accessibilityReduceMotion) private var reduceMotion

    var body: some View {
        Button("Tap Me") { }
            .scaleEffect(isPressed ? 0.95 : 1.0)
            .animation(reduceMotion ? nil : .spring(), value: isPressed)
            .onLongPressGesture(minimumDuration: .infinity, pressing: { pressing in
                isPressed = pressing
            }, perform: {})
    }
}

Accessible Form

struct AccessibleForm: View {
    @State private var email = ""
    @State private var password = ""
    @State private var emailError: String?
    @FocusState private var focusedField: Field?

    enum Field: Hashable {
        case email, password
    }

    var body: some View {
        Form {
            Section {
                TextField("Email", text: $email)
                    .focused($focusedField, equals: .email)
                    .textContentType(.emailAddress)
                    .keyboardType(.emailAddress)
                    .accessibilityLabel("Email address")
                    .accessibilityValue(email.isEmpty ? "Empty" : email)

                if let error = emailError {
                    Text(error)
                        .font(.caption)
                        .foregroundColor(.red)
                        .accessibilityLabel("Error: \(error)")
                }

                SecureField("Password", text: $password)
                    .focused($focusedField, equals: .password)
                    .textContentType(.password)
                    .accessibilityLabel("Password")
                    .accessibilityHint("Minimum 8 characters")
            }

            Button("Sign In") {
                signIn()
            }
            .accessibilityLabel("Sign in")
            .accessibilityHint("Double tap to sign in with entered credentials")
        }
        .onSubmit {
            switch focusedField {
            case .email:
                focusedField = .password
            case .password:
                signIn()
            case nil:
                break
            }
        }
        .onChange(of: emailError) { _, error in
            if error != nil {
                // Announce error to VoiceOver
                UIAccessibility.post(notification: .announcement,
                    argument: "Error: \(error ?? "")")
            }
        }
    }
}

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Quick Reference

WCAG AA Requirements

Criterion	Requirement	iOS Implementation
1.4.3 Contrast	4.5:1 normal, 3:1 large	Use semantic colors
1.4.4 Resize Text	200% without loss	Dynamic Type support
2.1.1 Keyboard	All functionality	VoiceOver navigation
2.4.7 Focus Visible	Clear focus indicator	@FocusState
2.5.5 Target Size	44x44pt minimum	.frame(minWidth:minHeight:)

Accessibility Traits

Trait	When to Use
.isButton	Custom tappable views
.isHeader	Section titles
.isSelected	Currently selected item
.isLink	Navigates to URL
.isImage	Meaningful images
.playsSound	Audio triggers
.startsMediaSession	Video/audio playback
.adjustable	Swipe up/down to change value

Focus Notifications

Notification	Use Case
.screenChanged	Major UI change, new screen
.layoutChanged	Minor UI update
.announcement	Status message
.pageScrolled	Scroll position changed

Red Flags

Smell	Problem	Fix
"Button" in label	Redundant	Remove type from label
Icon without label	Inaccessible	Add accessibilityLabel
.accessibilityHidden(true) on control	Can't interact	Remove or rethink
.font(.system(size:))	Doesn't scale	Use .font(.body)
Color-only status	Color-blind exclusion	Add icon or text
Animation ignores reduceMotion	Vestibular issues	Check environment
Decorative image without hidden	Noisy VoiceOver	accessibilityHidden(true)
Combined elements with separate actions	Can't interact individually	Keep separate or use custom actions