How Does Kotlin Multiplatform Render Jetpack Compose on iOS?

Kotlin Multiplatform (KMP) enables Jetpack Compose to work on iOS by leveraging Skia as the rendering engine through the JetBrains Compose Multiplatform framework. Here’s how it works:

🔹 1. Rendering with Skia (via Skiko)

• Skia is a cross-platform graphics engine used in Chrome, Android, and Flutter.

• Skiko (a Kotlin wrapper for Skia) enables Jetpack Compose to render UI on iOS.

• Compose UI elements are drawn onto a UIView using Skia, bypassing UIKit and SwiftUI.

🔹 2. UIKit Integration

• Jetpack Compose for iOS runs inside a UIViewController.

• It doesn’t use SwiftUI or UIKit components directly but can be embedded into an iOS app alongside native views.

🔹 3. Input and Event Handling

• Handles gestures, clicks, and interactions via Skiko.

• Touch events from UIViewController are forwarded to Compose.

🔹 4. Native Interoperability

• Developers can call iOS APIs (CoreLocation, AVFoundation, etc.) using KMP’s expect/actual mechanism.

• This allows native platform integration while keeping most UI logic in Compose.

🔹 5. Performance Considerations

• Compose for iOS does not use SwiftUI or UIKit natively, which may lead to performance trade-offs.

• Since it’s still in beta, further optimizations are expected.

🔹 6. Deployment & Debugging

• Requires macOS with Xcode for compilation.

• Runs within a UIViewController, making it deployable like any iOS app.

💡 Example: Integrating Compose in an iOS App

@Composable
fun Greeting(name: String) {
    Text("Hello, $name!")
}

// In the iOS App
fun MainViewController(): UIViewController =
    ComposeUIViewController { Greeting("iOS User") }        

Final Thoughts

Jetpack Compose Multiplatform enables shared UI development between Android and iOS, but its beta status means performance and stability are still evolving.