Stretchable

<img src="https://github.com/Livsy90/Stretchable/blob/main/demo.gif" height="450">

A SwiftUI helper that adds stretch / overscroll scaling effects to views inside a ScrollView, using modern APIs on iOS 17+ and a backported implementation for iOS 13+, all exposed through a single, consistent API.

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Features

• ✅ Works on iOS 13+
• ✅ Supports vertical and horizontal ScrollView
• ✅ Optional uniform scaling (both axes) or axis-only stretching
• ✅ Single, unified modifier API
• ✅ No custom containers
• ✅ Pure SwiftUI

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In Xcode:

Open your project

Go to File → Add Packages…

Enter the package URL:

https://github.com/Livsy90/Stretchable.git

Add the package to your target

Once added, import the module where needed:

import Stretchable

The stretchable(axis:uniform:) modifier will then be available on all View types.

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Demo

Typical use cases:

• Stretchy headers
• Pull-to-expand hero views
• Overscroll visual feedback
• Horizontal carousels with elastic leading edge

ScrollView {
    header
        .stretchable(axis: .vertical, uniform: true)
}

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API

extension View {
    func stretchable(
        axis: Axis = .vertical,
        uniform: Bool = false
    ) -> some View
}

Parameters

| Parameter | Description | |---------|-------------| | axis | .vertical for vertical ScrollView, .horizontal for horizontal | | uniform | If true, scales both axes. If false, scales only along axis |

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Usage Examples

Vertical ScrollView (Stretchy Header)

ScrollView {
    VStack {
        header
            .frame(height: 150)
            .stretchable(axis: .vertical, uniform: true)

        content
    }
}

Horizontal ScrollView

ScrollView(.horizontal) {
    HStack {
        header
            .frame(height: 150)
            .stretchable(axis: .horizontal, uniform: true)

        items
    }
}

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How It Works

iOS 17+

On iOS 17 and newer, the modifier uses:

• visualEffect
• GeometryProxy.frame(in: .scrollView)

This provides accurate overscroll detection relative to the scroll container and ensures native-quality behavior.

Older iOS versions Backport

Since .visualEffect and .scrollView coordinate space are unavailable on older versions, the backport uses:

• GeometryReader
• PreferenceKey

This approach approximates scroll-relative overscroll while remaining safe and performant on older iOS versions.

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Design Notes

• Stretching activates only when pulling past the start edge (top / leading).
• Normal scrolling does not trigger scaling.
• Anchors are chosen to match the scroll direction:
  • .bottom for vertical
  • .trailing for horizontal

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Requirements

• iOS 13.0+

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License

MIT