OpenAsyncImage

A backport implementation of SwiftUI's AsyncImage on Apple platform.

Overview

OpenAsyncImage provides a drop-in replacement for SwiftUI's AsyncImage that works across all supported platforms.

This package's source code is mainly taken from OpenSwiftUI.

Installation

Swift Package Manager

Add the following to your Package.swift file:

dependencies: [
    .package(url: "https://github.com/OpenSwiftUIProject/OpenAsyncImage.git", from: "0.1.0")
]

targets: [
    .target(
        name: "YourTarget",
        dependencies: [
            .product(name: "OpenAsyncImageKit", package: "OpenAsyncImage")
        ]
    )
]

Or add it directly in Xcode using File → Add Package Dependencies…

Usage

Simply import OpenAsyncImageKit and use it the same way you would use SwiftUI's AsyncImage:

import SwiftUI
import OpenAsyncImageKit

struct ContentView: View {
    var body: some View {
        AsyncImage(url: URL(string: "https://example.com/image.jpg")) { phase in
            switch phase {
            case .empty:
                ProgressView()
            case .success(let image):
                image
                    .resizable()
                    .aspectRatio(contentMode: .fit)
            case .failure:
                Image(systemName: "photo")
                    .imageScale(.large)
            }
        }
    }
}

Documentation

Detailed documentation for OpenAsyncImage can be found on Swift Package Index.

Advantages

• iOS 13+ Support: Brings AsyncImage functionality to earlier iOS versions instead of being limited to iOS 15+
• Optimized Implementation: Provides an implementation based on iOS 18.0 with additional State.wrappedValue setter optimization
• Consistency: Delivers consistent behavior across all supported platforms
• Debuggable: Easy to debug and understand why something might not be working correctly

Limitations

• No Future Optimizations: Cannot automatically inherit future optimizations made to SwiftUI.AsyncImage with OS updates
• Missing Redaction Support: Image.redacted can not be implemented by the public API of SwiftUI by now, so the placeholder effect in AsyncImage(url:scale:) is not fully equivalent to SwiftUI's implementation

API Reference

OpenAsyncImage provides the same API as SwiftUI's AsyncImage:

public init(
    url: URL?, 
    scale: CGFloat = 1.0, 
    transaction: Transaction = Transaction(), 
    @ViewBuilder content: @escaping (AsyncImagePhase) -> Content
)

public init<I, P>(
    url: URL?,
    scale: CGFloat = 1,
    @ViewBuilder content: @escaping (Image) -> I,
    @ViewBuilder placeholder: @escaping () -> P
) where Content == _ConditionalContent<I, P>, I: View, P: View {

public init(
    url: URL?, 
    scale: CGFloat = 1
) where Content == Image

Credits

To make AsyncImage available on earlier versions, code from the following libraries was used and modified:

• SwiftUIBackports
• AsyncCompatibilityKit

Disclaimer

The assets images used in this documentation are from Apple's documentation website and the property belongs to Apple Inc.

License

OpenAsyncImage is available under the MIT license. See the LICENSE file for more info.