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/swiftui-gestures

@45c9085

Implement, review, or improve SwiftUI gesture handling. Use when adding tap, long press, drag, magnify, or rotate gestures, composing gestures with simultaneously/sequenced/exclusively, managing transient state with @GestureState, resolving parent/child gesture conflicts with highPriorityGesture or simultaneousGesture, building custom Gesture protocol conformances, or migrating from deprecated MagnificationGesture to MagnifyGesture or using the newer RotateGesture.

Use this Skill: https://skilld.dev/gh/dpearson2699/swift-ios-skills/swiftui-gestures

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SKILL.md

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SwiftUI Gestures (iOS 26+)

Review, write, and fix SwiftUI gesture interactions. Apply modern gesture APIs with correct composition, state management, and conflict resolution using Swift 6.3 patterns.

Scope boundary: This skill owns SwiftUI gesture recognition, composition, gesture state, and gesture-specific accessibility alternatives. Broader SwiftUI architecture/state ownership belongs in swiftui-patterns; list, scroll, form, and control layout belongs in swiftui-layout-components; broad UIKit bridging belongs in swiftui-uikit-interop.

When correcting Apple API availability, deprecation, or behavior claims, cite the relevant Sosumi or official Apple documentation URL in the response.

Contents

Gesture Overview

Gesture Type Value Since
TapGesture Discrete Void iOS 13
LongPressGesture Discrete Bool iOS 13
DragGesture Continuous DragGesture.Value iOS 13
MagnifyGesture Continuous MagnifyGesture.Value iOS 17
RotateGesture Continuous RotateGesture.Value iOS 17
SpatialTapGesture Discrete SpatialTapGesture.Value iOS 16

Discrete gestures fire once (.onEnded). Continuous gestures stream updates (.onChanged, .onEnded, .updating).

TapGesture

Recognizes one or more taps. Use the count parameter for multi-tap.

// Single, double, and triple tap
TapGesture()            .onEnded { tapped.toggle() }
TapGesture(count: 2)    .onEnded { handleDoubleTap() }
TapGesture(count: 3)    .onEnded { handleTripleTap() }

// Shorthand modifier
Text("Tap me").onTapGesture(count: 2) { handleDoubleTap() }

LongPressGesture

Succeeds after the user holds for minimumDuration. Fails if finger moves beyond maximumDistance.

// Basic long press (0.5s default)
LongPressGesture()
    .onEnded { _ in showMenu = true }

// Custom duration and distance tolerance
LongPressGesture(minimumDuration: 1.0, maximumDistance: 10)
    .onEnded { _ in triggerHaptic() }

With visual feedback via @GestureState + .updating():

@GestureState private var isPressing = false

Circle()
    .fill(isPressing ? .red : .blue)
    .scaleEffect(isPressing ? 1.2 : 1.0)
    .gesture(
        LongPressGesture(minimumDuration: 0.8)
            .updating($isPressing) { current, state, _ in state = current }
            .onEnded { _ in completedLongPress = true }
    )

Shorthand: .onLongPressGesture(minimumDuration:perform:onPressingChanged:).

DragGesture

Tracks finger movement. Value provides startLocation, location, translation, velocity, and predictedEndTranslation. DragGesture.Value.velocity is available with DragGesture from iOS 13+; do not confuse it with iOS 17+ gesture types such as MagnifyGesture and RotateGesture.

@State private var offset = CGSize.zero

RoundedRectangle(cornerRadius: 16)
    .fill(.blue)
    .frame(width: 100, height: 100)
    .offset(offset)
    .gesture(
        DragGesture()
            .onChanged { value in offset = value.translation }
            .onEnded { _ in withAnimation(.spring) { offset = .zero } }
    )

Configure minimum distance and coordinate space:

DragGesture(minimumDistance: 20, coordinateSpace: .global)

MagnifyGesture (iOS 17+)

Replaces the deprecated MagnificationGesture. Tracks pinch-to-zoom scale.

@GestureState private var magnifyBy = 1.0

Image("photo")
    .resizable().scaledToFit()
    .scaleEffect(magnifyBy)
    .gesture(
        MagnifyGesture()
            .updating($magnifyBy) { value, state, _ in
                state = value.magnification
            }
    )

RotateGesture (iOS 17+)

RotateGesture is the newer alternative to RotationGesture. Tracks two-finger rotation angle.

@State private var angle = Angle.zero

Rectangle()
    .fill(.blue).frame(width: 200, height: 200)
    .rotationEffect(angle)
    .gesture(
        RotateGesture(minimumAngleDelta: .degrees(1))
            .onChanged { value in angle = value.rotation }
    )

For persisted, clamped magnification and combined rotation examples, load references/gesture-patterns.md.

Gesture Composition

.simultaneously(with:) — both gestures recognized at the same time

let magnify = MagnifyGesture()
    .onChanged { value in scale = value.magnification }

let rotate = RotateGesture()
    .onChanged { value in angle = value.rotation }

Image("photo")
    .scaleEffect(scale)
    .rotationEffect(angle)
    .gesture(magnify.simultaneously(with: rotate))

The value is SimultaneousGesture.Value with .first and .second optionals.

.sequenced(before:) — first must succeed before second begins

let longPressBeforeDrag = LongPressGesture(minimumDuration: 0.5)
    .sequenced(before: DragGesture())
    .onEnded { value in
        guard case .second(true, let drag?) = value else { return }
        finalOffset.width += drag.translation.width
        finalOffset.height += drag.translation.height
    }

.exclusively(before:) — only one succeeds (first has priority)

let doubleTapOrLongPress = TapGesture(count: 2)
    .exclusively(before:
        LongPressGesture()
    )
    .onEnded { result in
        switch result {
        case .first(_): handleDoubleTap()
        case .second(_): handleLongPress()
        }
    }

@GestureState

@GestureState is a property wrapper that automatically resets to its initial value when the gesture ends. Use for transient feedback; use @State for values that persist.

@GestureState private var dragOffset = CGSize.zero  // resets to .zero
@State private var position = CGSize.zero            // persists

Circle()
    .offset(
        x: position.width + dragOffset.width,
        y: position.height + dragOffset.height
    )
    .gesture(
        DragGesture()
            .updating($dragOffset) { value, state, _ in
                state = value.translation
            }
            .onEnded { value in
                position.width += value.translation.width
                position.height += value.translation.height
            }
    )

Custom reset with animation: @GestureState(resetTransaction: Transaction(animation: .spring))

Adding Gestures to Views

Three modifiers control gesture priority in the view hierarchy:

Modifier Behavior
.gesture() Lower precedence than gestures already defined by the view or its children.
.highPriorityGesture() Added gesture takes precedence over existing gestures.
.simultaneousGesture() Added gesture processes at the same priority as existing gestures.
let parentTap = TapGesture().onEnded { handleParent() }

VStack {
    Image(systemName: "star.fill")
        .onTapGesture { handleChild() }
}
.simultaneousGesture(parentTap) // Both handlers run on child content.

Use .gesture(parentTap) for the default lower-precedence parent gesture, or .highPriorityGesture(parentTap) when the added parent gesture should win.

GestureMask

Control which gestures participate when using .gesture(_:including:):

.gesture(drag, including: .gesture)   // added gesture; disables subview gestures
.gesture(drag, including: .subviews)  // subview gestures; disables added gesture
.gesture(drag, including: .all)       // default: added + subview gestures
.gesture(drag, including: .none)      // disables added + subview gestures

Custom Gesture Protocol

Create reusable gestures by conforming to Gesture:

struct SwipeGesture: Gesture {
    enum Direction { case left, right, up, down }
    typealias Value = Direction

    let minimumDistance: CGFloat

    init(minimumDistance: CGFloat = 50) {
        self.minimumDistance = minimumDistance
    }

    var body: AnyGesture<Direction> {
        AnyGesture(
            DragGesture(minimumDistance: minimumDistance)
                .map { value in
                    let h = value.translation.width, v = value.translation.height
                    if abs(h) > abs(v) {
                        return h > 0 ? .right : .left
                    } else {
                        return v > 0 ? .down : .up
                    }
                }
        )
    }
}

// Usage
Rectangle().gesture(SwipeGesture().onEnded { print("Swiped \($0)") })

Wrap in a View extension for ergonomic API:

extension View {
    func onSwipe(perform action: @escaping (SwipeGesture.Direction) -> Void) -> some View {
        gesture(SwipeGesture().onEnded(action))
    }
}

Common Mistakes

1. Misreading parent/child gesture precedence

Do not assume a parent .gesture() overrides child gestures. Choose the relationship explicitly as shown in Adding Gestures to Views.

2. Using @State instead of @GestureState for transient state

Use @GestureState for values that should reset when recognition ends; keep persistent results in @State. See @GestureState.

3. Not using .updating() for intermediate feedback

// DON'T: No visual feedback during long press
LongPressGesture(minimumDuration: 2.0)
    .onEnded { _ in showResult = true }

// DO: Provide feedback while pressing
@GestureState private var isPressing = false

LongPressGesture(minimumDuration: 2.0)
    .updating($isPressing) { current, state, _ in
        state = current
    }
    .onEnded { _ in showResult = true }

4. Using deprecated gesture types on iOS 17+

// DON'T: Deprecated since iOS 17
MagnificationGesture()   // deprecated — use MagnifyGesture()

// DO: Use newer gesture types
MagnifyGesture()         // iOS 17+
RotateGesture()          // iOS 17+ (newer alternative to RotationGesture)

5. Heavy computation in onChanged

// DON'T: Expensive work called every frame (~60-120 Hz)
DragGesture()
    .onChanged { value in
        let result = performExpensiveHitTest(at: value.location)
        let filtered = applyComplexFilter(result)
        updateModel(filtered)
    }

// DO: Throttle or defer expensive work
DragGesture()
    .onChanged { value in
        dragPosition = value.location  // lightweight state update only
    }
    .onEnded { value in
        performExpensiveHitTest(at: value.location)  // once at end
    }

6. Using onTapGesture for actions that should be a Button

// DON'T: onTapGesture has no accessibility traits, VoiceOver role,
// Voice Control targeting, Switch Control scanning, or keyboard activation
Text("Delete")
    .onTapGesture { deleteItem() }

// DO: Button provides all of these automatically
Button("Delete", role: .destructive) { deleteItem() }

// DO: For custom visuals, use ButtonStyle instead of onTapGesture
Button { toggleExpanded() } label: {
    CardView()
}
.buttonStyle(.plain)

Reserve onTapGesture for multi-tap (count: 2+), tap-location-dependent behavior, or adding tap recognition to non-interactive content that already has appropriate accessibility traits.

Review Checklist

  • Correct gesture type: MagnifyGesture/RotateGesture (not deprecated Magnification/Rotation variants)
  • @GestureState used for transient values that should reset; @State for persisted values
  • .updating() provides intermediate visual feedback during continuous gestures
  • Parent/child conflicts resolved with .highPriorityGesture() or .simultaneousGesture()
  • onChanged closures are lightweight — no heavy computation every frame
  • Composed gestures use correct combinator: simultaneously, sequenced, or exclusively
  • Persisted scale/rotation clamped to reasonable bounds in onEnded
  • Custom Gesture conformances return a gesture body; use AnyGesture<Value> when mapping to a custom Value
  • Gesture-driven animations use .spring or similar for natural deceleration
  • GestureMask considered when mixing gestures across view hierarchy levels
  • onTapGesture only used where count > 1, tap location, or coordinate space matters — plain single-tap actions use Button instead

References

Source: SKILL.md on GitHub

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  • Gen Agent Trust Hub16d

    The skill provides comprehensive documentation and patterns for SwiftUI gesture handling. No security issues were detected.

  • Socket16d

    No alerts

  • Snyk16d

    Risk: LOW · No issues

  • ZeroLeaks5mo

    Score: 93/100 · 2 sections analyzed

Signed by skilld at 45c9085. This ties the file your Agent reads to that commit on GitHub. It does not review the instructions.

Last checked against GitHub 2 days ago.

Steadyupdated 3 months ago
  • swiftui
  • gestures
  • ios
  • tap
  • drag
  • long-press
  • magnify
  • rotate
  • state-management

README badge

README badge for dpearson2699/swift-ios-skills/swiftui-gestures

Implement, review, and fix SwiftUI gesture handling using modern APIs including TapGesture, LongPressGesture, DragGesture, MagnifyGesture, and RotateGesture. Covers gesture composition (simultaneously, sequenced, exclusively), transient state management with @GestureState, and parent/child gesture conflict resolution using highPriorityGesture or simultaneousGesture.

Generated from the current SKILL.md.

Does this skill cover iOS 13 gestures like TapGesture and DragGesture, or only iOS 17+?
It covers both. The skill documents TapGesture, LongPressGesture, DragGesture, and SpatialTapGesture (iOS 13–16 baseline), plus newer iOS 17+ gestures like MagnifyGesture and RotateGesture, with clear deprecation notes on old types like MagnificationGesture.
How does @GestureState differ from @State for gesture handling?
@GestureState automatically resets to its initial value when the gesture ends, making it ideal for transient feedback like drag offsets. @State persists across gesture cycles and requires manual reset.
How do I resolve conflicts between parent and child gestures?
Use .simultaneousGesture() to let both fire, .highPriorityGesture() to give the parent precedence, or .gesture() with GestureMask to control which gestures participate in the hierarchy.
Can I build custom gestures?
Yes. Conform to the Gesture protocol and compose existing gestures like DragGesture in the body property, then optionally wrap it in a View extension for an ergonomic API.
What should I do about heavy computation during drag or continuous gestures?
Update lightweight state in onChanged and defer expensive work like hit tests or filtering to onEnded, or throttle updates to avoid frame-rate performance hits.

Generated from the current SKILL.md. These answers refresh after source changes.