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SwiftCrossUI

https://github.com/moreswift/swift-cross-ui
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SwiftCrossUI is a SwiftUI-like framework for creating cross-platform apps across macOS, Linux,...
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### Run examples with Swift Bundler

Source: https://github.com/moreswift/swift-cross-ui/blob/main/Sources/SwiftCrossUI/SwiftCrossUI.docc/Examples.md

Clone the repository, navigate to the Examples directory, and run an example on the host machine, a connected device, or a simulator. The --device and --simulator flags are macOS only.

```sh
git clone https://github.com/moreSwift/swift-cross-ui
cd swift-cross-ui/Examples

# Run on host machine
swift-bundler run CounterExample
# Run on a connected device with "iPhone" in its name (macOS only)
swift-bundler run CounterExample --device iPhone
# Run on a simulator with "iPhone 16" in its name (macOS only)
swift-bundler run CounterExample --simulator "iPhone 16"
```

--------------------------------

### Run SwiftCrossUI examples with Swift Bundler

Source: https://github.com/moreswift/swift-cross-ui/blob/main/README.md

Clone the repository and run the CounterExample on the host machine, a connected device, or a simulator. Requires Swift Bundler installed. The --device and --simulator flags are macOS only and support Android devices/emulators as well.

```sh
git clone https://github.com/moreSwift/swift-cross-ui
cd swift-cross-ui/Examples

# Run on host machine
swift-bundler run CounterExample

# Run on a connected device with "iPhone" in its name (macOS only)
#   Supports Android devices as well
swift-bundler run CounterExample --device iPhone

# Run on a simulator with "iPhone 16" in its name (macOS only)
#   Supports Android emulators as well
swift-bundler run CounterExample --simulator "iPhone 16"
```

--------------------------------

### Run example with a different backend

Source: https://github.com/moreswift/swift-cross-ui/blob/main/Sources/SwiftCrossUI/SwiftCrossUI.docc/Examples.md

Set the SCUI_DEFAULT_BACKEND environment variable to choose a backend other than the default when running an example with Swift Bundler.

```sh
SCUI_DEFAULT_BACKEND=Gtk3Backend swift-bundler run ExampleToRun
```

--------------------------------

### Install vcpkg on Windows

Source: https://github.com/moreswift/swift-cross-ui/blob/main/Sources/SwiftCrossUI/SwiftCrossUI.docc/Backends/GtkBackend.md

Clone and bootstrap vcpkg on Windows. vcpkg must be installed at the root of a drive.

```shell
> git clone https://github.com/microsoft/vcpkg C:\vcpkg
> C:\vcpkg\bootstrap-vcpkg.bat
```

--------------------------------

### Run SwiftCrossUI examples with SwiftPM (non-recommended)

Source: https://github.com/moreswift/swift-cross-ui/blob/main/README.md

Alternative method to run examples using SwiftPM. Resources may not load as expected, deep linking may not work, and iOS/tvOS targets are unsupported.

```sh
# Non-recommended method
swift run CounterExample
```

--------------------------------

### Use Gtk3Backend in YourApp.swift

Source: https://github.com/moreswift/swift-cross-ui/blob/main/Sources/SwiftCrossUI/SwiftCrossUI.docc/Backends/Gtk3Backend.md

Example SwiftUI app using Gtk3Backend, showing how to import the backend and optionally initialize it with an app identifier.

```swift
import SwiftCrossUI
import Gtk3Backend

@main
struct YourApp: App {
    // You can explicitly initialize your app's chosen backend if you desire.
    // This happens automatically when you import any of the built-in backends.
    //
    // var backend = Gtk3Backend()
    //
    // If you aren't using Swift Bundler, you may have to explicitly provide
    // your app's identifier for some Gtk3Backend features to work correctly
    // (such as handling custom URL schemes).
    //
    // var backend = Gtk3Backend(appIdentifier: "com.example.YourApp")
    
    var body: some Scene {
        WindowGroup {
            Text("Hello, World!")
                .padding()
        }
    }
}
```

--------------------------------

### Install Gtk3Backend dependencies on Debian-based distros

Source: https://github.com/moreswift/swift-cross-ui/blob/main/Sources/SwiftCrossUI/SwiftCrossUI.docc/Backends/Gtk3Backend.md

Install required system dependencies for Gtk3Backend on Debian-based Linux distributions using apt.

```shell
$ sudo apt install libgtk-3-dev clang
```

--------------------------------

### Install Gtk 4 via Homebrew on macOS

Source: https://github.com/moreswift/swift-cross-ui/blob/main/Sources/SwiftCrossUI/SwiftCrossUI.docc/Backends/GtkBackend.md

Install pkg-config and gtk4 using Homebrew on macOS.

```shell
$ brew install pkg-config gtk4
```

--------------------------------

### SwiftCrossUI example: Package.swift and YourApp.swift

Source: https://github.com/moreswift/swift-cross-ui/blob/main/README.md

Together these files form the basic SwiftCrossUI example app. Package.swift adds the swift-cross-ui dependency and links the SwiftCrossUI and DefaultBackend products. YourApp.swift creates a @main App with a WindowGroup containing an HStack of decrement and increment buttons and a count label.

```swift
import PackageDescription

let package = Package(
    name: "YourApp",
    dependencies: [
        .package(
            url: "https://github.com/moreSwift/swift-cross-ui",
            .upToNextMinor(from: "0.2.0")
        ),
    ],
    targets: [
        .executableTarget(
            name: "YourApp",
            dependencies: [
                .product(name: "SwiftCrossUI", package: "swift-cross-ui"),
                .product(name: "DefaultBackend", package: "swift-cross-ui"),
            ]
        ),
    ]
)
```

```swift
import SwiftCrossUI
import DefaultBackend

@main
struct YourApp: App {
    @State var count = 0

    var body: some Scene {
        WindowGroup("YourApp") {
            HStack {
                Button("-") { count -= 1 }
                Text("Count: \(count)")
                Button("+") { count += 1 }
            }.padding()
        }
    }
}
```

--------------------------------

### Install Gtk 4 globally with vcpkg (x64)

Source: https://github.com/moreswift/swift-cross-ui/blob/main/Sources/SwiftCrossUI/SwiftCrossUI.docc/Backends/GtkBackend.md

Install Gtk 4 globally for x64 Windows using vcpkg. Run from the root of your drive to avoid manifest mode.

```shell
> cd C:\
> C:\vcpkg\vcpkg.exe install gtk --triplet x64-windows
```

--------------------------------

### Install Gtk3Backend dependencies on Fedora-based distros

Source: https://github.com/moreswift/swift-cross-ui/blob/main/Sources/SwiftCrossUI/SwiftCrossUI.docc/Backends/Gtk3Backend.md

Install required system dependencies for Gtk3Backend on Fedora-based Linux distributions using dnf.

```shell
$ sudo dnf install gtk3-devel clang
```

--------------------------------

### Install Windows SDK 10.0.17763 with winget

Source: https://github.com/moreswift/swift-cross-ui/blob/main/Sources/SwiftCrossUI/SwiftCrossUI.docc/Backends/WinUIBackend.md

Install the Windows SDK 10.0.17763 required at compile time. If version 17763 fails, try 17736 due to a typo in older Windows versions.

```shell
> winget install --id Microsoft.WindowsSDK.10.0.17763
```

--------------------------------

### Full documentation comment example

Source: https://github.com/moreswift/swift-cross-ui/blob/main/CONTRIBUTING.md

Example of a documentation comment that follows all the rules: sentence case, punctuation, symbol links, named links, and documentation of parameters, return type, and preconditions.

```swift
/// Computes this view's layout after a state change or a change in
/// available space.
///
/// Implementations of this method should follow similar semantics to the
/// [SwiftUI layout algorithm][algorithm].
///
/// The default implementation lives at
/// ``View/defaultComputeLayout(_:children:proposedSize:environment:backend:)-(_,any ViewGraphNodeChildren,_,_,_)``.
///
/// [algorithm]: https://www.hackingwithswift.com/books/ios-swiftui/how-layout-works-in-swiftui
///
/// - Precondition: Requires that the target widget has been added to its parent widget.
/// - Parameters:
///   - widget: The widget to compute the layout for.
///   - children: The view's child nodes.
///   - proposedSize: The size suggested by the parent container.
///   - environment: The environment to compute the layout in.
///   - backend: The backend used to create the widget.
/// - Returns: The view's computed layout result.
func computeLayout<Backend: BaseAppBackend>(
    _ widget: Backend.Widget,
    children: any ViewGraphNodeChildren,
    proposedSize: ProposedViewSize,
    environment: EnvironmentValues,
    backend: Backend
) -> ViewLayoutResult
```

--------------------------------

### Good comment examples

Source: https://github.com/moreswift/swift-cross-ui/blob/main/CONTRIBUTING.md

Shows examples of well-formatted comments. Includes a properly formatted single-line comment and a TODO comment with a GitHub username.

```swift
// This comment is well formatted

// TODO(stackotter): Make this more robust once we have a state dependency
//   tracking system
```

--------------------------------

### Install Gtk 4 and clang on Debian-based Linux

Source: https://github.com/moreswift/swift-cross-ui/blob/main/Sources/SwiftCrossUI/SwiftCrossUI.docc/Backends/GtkBackend.md

Use apt to install the required Gtk 4 development headers and clang on Debian-based distributions.

```shell
$ sudo apt install libgtk-4-dev clang
```

--------------------------------

### Install Gtk3Backend dependencies on macOS

Source: https://github.com/moreswift/swift-cross-ui/blob/main/Sources/SwiftCrossUI/SwiftCrossUI.docc/Backends/Gtk3Backend.md

Install required system dependencies for Gtk3Backend on macOS using Homebrew.

```shell
$ brew install pkg-config gtk+3
```

--------------------------------

### Install Gtk 4 globally with vcpkg (arm64)

Source: https://github.com/moreswift/swift-cross-ui/blob/main/Sources/SwiftCrossUI/SwiftCrossUI.docc/Backends/GtkBackend.md

Install Gtk 4 globally for arm64 Windows using vcpkg. Run from the root of your drive to avoid manifest mode.

```shell
> cd C:\
> C:\vcpkg\vcpkg.exe install gtk --triplet arm64-windows
```

--------------------------------

### Install Gtk 4 and clang on Fedora-based Linux

Source: https://github.com/moreswift/swift-cross-ui/blob/main/Sources/SwiftCrossUI/SwiftCrossUI.docc/Backends/GtkBackend.md

Use dnf to install the required Gtk 4 development headers and clang on Fedora-based distributions.

```shell
$ sudo dnf install gtk4-devel clang
```

--------------------------------

### Bad comment examples

Source: https://github.com/moreswift/swift-cross-ui/blob/main/CONTRIBUTING.md

Shows examples of poorly formatted comments to avoid. Includes missing space after double slash, incorrect capitalization, multi-line comment syntax, and TODO without a GitHub username.

```swift
//this comment is poorly formatted

//This comment is poorly formatted

/*
  This comment uses the multi-line comment syntax,
  which SwiftCrossUI doesn't use
*/

// TODO: Fix this todo comment that isn't attributed to a GitHub username
```

--------------------------------

### Run Gtk3Backend tests with SCUI_TEST_GTK3BACKEND=1

Source: https://github.com/moreswift/swift-cross-ui/blob/main/CONTRIBUTING.md

Runs Gtk3Backend-specific tests alongside the default tests. These tests are disabled by default because many contributors don't have Gtk 3 installed; CI always runs them.

```sh
SCUI_TEST_GTK3BACKEND=1 ./Scripts/test.sh
```

--------------------------------

### Running with hot reloading: swift-bundler run --hot

Source: https://github.com/moreswift/swift-cross-ui/blob/main/Sources/SwiftCrossUI/SwiftCrossUI.docc/Hot reloading.md

Start a hot reloading session with Swift Bundler. The initial build may take longer than a regular incremental build, but subsequent builds should be faster. Swift Bundler currently only observes the app's Sources directory.

```sh
swift-bundler run --hot
```

--------------------------------

### vcpkg.json manifest for Gtk dependency

Source: https://github.com/moreswift/swift-cross-ui/blob/main/Sources/SwiftCrossUI/SwiftCrossUI.docc/Backends/GtkBackend.md

Create this vcpkg.json file at the root of your project to declare the gtk dependency for project-local installation.

```json
{
    "name": "project-name",
    "version-string": "main",
    "dependencies": ["gtk"]
}
```

--------------------------------

### YourApp.swift: Define app entry point

Source: https://github.com/moreswift/swift-cross-ui/blob/main/Sources/SwiftCrossUI/SwiftCrossUI.docc/Backends/AndroidBackend.md

Define the main app struct with an optional backend initialization and a simple WindowGroup scene.

```swift
import SwiftCrossUI
import AndroidBackend

@main
struct YourApp: App {
    // You can explicitly initialize your app's chosen backend if you desire.
    // This happens automatically when you import any of the built-in backends.
    //
    // var backend = AndroidBackend()
    //
    // If you want to hook into your Android app's lifecycle methods you can
    // provide your own ActivityDelegate.
    //
    // var backend = AndroidBackend(delegate: MyActivityDelegate())
    
    var body: some Scene {
        WindowGroup {
            Text("Hello, World!")
                .padding()
        }
    }
}
```

--------------------------------

### Preview documentation with preview_docs.sh

Source: https://github.com/moreswift/swift-cross-ui/blob/main/CONTRIBUTING.md

Commands to preview documentation. The first builds SwiftCrossUI to obtain symbol graphs, the second skips symbol graphs for faster previews when working on articles or tutorials.

```sh
# Preview docs (builds SwiftCrossUI first to obtain symbol graphs, and then
# previews Sources/SwiftCrossUI/SwiftCrossUI.docc)
./Scripts/preview_docs.sh

# Preview docs without symbol graphs (faster if just working on articles/tutorials)
SKIP_SYMBOL_GRAPHS=1 ./Scripts/preview_docs.sh
```

--------------------------------

### YourApp.swift: Initialize AppKitBackend and define the app

Source: https://github.com/moreswift/swift-cross-ui/blob/main/Sources/SwiftCrossUI/SwiftCrossUI.docc/Backends/AppKitBackend.md

Shows the main app structure using SwiftCrossUI and AppKitBackend. The backend is automatically initialized when importing any built-in backend, but you can explicitly initialize it if desired.

```swift
import SwiftCrossUI
import AppKitBackend

@main
struct YourApp: App {
    // You can explicitly initialize your app's chosen backend if you desire.
    // This happens automatically when you import any of the built-in backends.
    //
    // var backend = AppKitBackend()
    
    var body: some Scene {
        WindowGroup {
            Text("Hello, World!")
                .padding()
        }
    }
}
```

--------------------------------

### YourApp.swift: Define app with GtkBackend

Source: https://github.com/moreswift/swift-cross-ui/blob/main/Sources/SwiftCrossUI/SwiftCrossUI.docc/Backends/GtkBackend.md

Defines the main app entry point using the GtkBackend. The backend is initialized automatically when importing GtkBackend, but can be explicitly created with GtkBackend() or GtkBackend(appIdentifier:) if needed.

```swift
import SwiftCrossUI
import GtkBackend

@main
struct YourApp: App {
    // You can explicitly initialize your app's chosen backend if you desire.
    // This happens automatically when you import any of the built-in backends.
    //
    // var backend = GtkBackend()
    //
    // If you aren't using Swift Bundler, you may have to explicitly provide
    // your app's identifier for some Gtk3Backend features to work correctly
    // (such as handling custom URL schemes).
    //
    // var backend = GtkBackend(appIdentifier: "com.example.YourApp")
    
    var body: some Scene {
        WindowGroup {
            Text("Hello, World!")
                .padding()
        }
    }
}
```

--------------------------------

### Run on Android device or emulator

Source: https://github.com/moreswift/swift-cross-ui/blob/main/Sources/SwiftCrossUI/SwiftCrossUI.docc/Backends/AndroidBackend.md

Commands to list devices, run on a device, list emulators, and run on an emulator using Swift Bundler.

```sh
# List available Android devices
swift-bundler devices list --os android

# Run on your device
swift-bundler run --device "Your Device"

# List available Android emulators
swift-bundler simulators list --os android

# Run on your emulator
swift-bundler run --simulator "Your Simulator"
```

--------------------------------

### Create a WinUIBackend app in YourApp.swift

Source: https://github.com/moreswift/swift-cross-ui/blob/main/Sources/SwiftCrossUI/SwiftCrossUI.docc/Backends/WinUIBackend.md

Define a minimal SwiftCrossUI app using the WinUIBackend. Importing WinUIBackend automatically selects the backend; you can optionally initialize it explicitly.

```swift
import SwiftCrossUI
import WinUIBackend

@main
struct YourApp: App {
    // You can explicitly initialize your app's chosen backend if you desire.
    // This happens automatically when you import any of the built-in backends.
    //
    // var backend = WinUIBackend()
    
    var body: some Scene {
        WindowGroup {
            Text("Hello, World!")
                .padding()
        }
    }
}
```

--------------------------------

### Package.swift: Add SwiftCrossUI and GtkBackend dependencies

Source: https://github.com/moreswift/swift-cross-ui/blob/main/Sources/SwiftCrossUI/SwiftCrossUI.docc/Backends/GtkBackend.md

Adds SwiftCrossUI and GtkBackend as dependencies for the YourApp executable target in the Package.swift manifest.

```swift
// ...
let package = Package(
    // ...
    targets: [
        // ...
        .executableTarget(
            name: "YourApp",
            dependencies: [
                .product(name: "SwiftCrossUI", package: "swift-cross-ui"),
                .product(name: "GtkBackend", package: "swift-cross-ui"),
            ]
        ),
        // ...
    ],
    // ...
)
```

--------------------------------

### YourApp.swift: Use DefaultBackend in your app

Source: https://github.com/moreswift/swift-cross-ui/blob/main/Sources/SwiftCrossUI/SwiftCrossUI.docc/Backends/DefaultBackend.md

Imports SwiftCrossUI and DefaultBackend, and defines the main app structure. The backend is automatically initialized when importing any built-in backend; you can optionally explicitly initialize it by uncommenting the 'var backend = DefaultBackend()' line.

```swift
import SwiftCrossUI
import DefaultBackend

@main
struct YourApp: App {
    // You can explicitly initialize your app's chosen backend if you desire.
    // This happens automatically when you import any of the built-in backends.
    //
    // var backend = DefaultBackend()
    
    var body: some Scene {
        WindowGroup {
            Text("Hello, World!")
                .padding()
        }
    }
}
```

--------------------------------

### YourApp.swift: Define app with UIKitBackend

Source: https://github.com/moreswift/swift-cross-ui/blob/main/Sources/SwiftCrossUI/SwiftCrossUI.docc/Backends/UIKitBackend.md

Defines the main app structure using SwiftCrossUI and UIKitBackend. The backend is automatically selected when importing UIKitBackend, but you can explicitly initialize it or provide a custom UIApplicationDelegate subclass via the alternate initializer.

```swift
import SwiftCrossUI
import UIKitBackend

@main
struct YourApp: App {
    // You can explicitly initialize your app's chosen backend if you desire.
    // This happens automatically when you import any of the built-in backends.
    //
    // var backend = UIKitBackend()
    //
    // You can register a custom UIApplicationDelegate by subclassing
    // UIKitBackend.ApplicationDelegate and providing it to UIKitBackend
    // via the alternate initializer.
    //
    // var backend = UIKitBackend(appDelegateClass: YourAppDelegate.self)
    
    var body: some Scene {
        WindowGroup {
            Text("Hello, World!")
                .padding()
        }
    }
}
```

--------------------------------

### Package.swift: Add SwiftCrossUI and DefaultBackend dependencies

Source: https://github.com/moreswift/swift-cross-ui/blob/main/Sources/SwiftCrossUI/SwiftCrossUI.docc/Backends/DefaultBackend.md

Declares the SwiftCrossUI and DefaultBackend products as dependencies for the executable target named 'YourApp'. This is required to use the DefaultBackend in your app.

```swift
// ...
let package = Package(
    // ...
    targets: [
        // ...
        .executableTarget(
            name: "YourApp",
            dependencies: [
                .product(name: "SwiftCrossUI", package: "swift-cross-ui"),
                .product(name: "DefaultBackend", package: "swift-cross-ui"),
            ]
        ),
        // ...
    ],
    // ...
)
```

--------------------------------

### Add Gtk3Backend to Package.swift

Source: https://github.com/moreswift/swift-cross-ui/blob/main/Sources/SwiftCrossUI/SwiftCrossUI.docc/Backends/Gtk3Backend.md

Add the Gtk3Backend product as a dependency to your executable target in Package.swift.

```swift
// ...
let package = Package(
    // ...
    targets: [
        // ...
        .executableTarget(
            name: "YourApp",
            dependencies: [
               .product(name: "SwiftCrossUI", package: "swift-cross-ui"),
               .product(name: "Gtk3Backend", package: "swift-cross-ui"),
            ]
        ),
        // ...
    ],
    // ...
)
```

--------------------------------

### Package.swift: Add AndroidBackend dependency

Source: https://github.com/moreswift/swift-cross-ui/blob/main/Sources/SwiftCrossUI/SwiftCrossUI.docc/Backends/AndroidBackend.md

Add the AndroidBackend product to your executable target's dependencies in Package.swift.

```swift
// ...
let package = Package(
    // ...
    targets: [
        // ...
        .executableTarget(
            name: "YourApp",
            dependencies: [
                .product(name: "SwiftCrossUI", package: "swift-cross-ui"),
                .product(name: "AndroidBackend", package: "swift-cross-ui"),
            ]
        ),
        // ...
    ],
    // ...
)
```

--------------------------------

### Run SwiftCrossUI tests with ./Scripts/test.sh

Source: https://github.com/moreswift/swift-cross-ui/blob/main/CONTRIBUTING.md

Runs SwiftCrossUI's tests. The script is required because running `swift test` without arguments builds all backends, including unsupported ones on the current platform.

```sh
./Scripts/test.sh
```

--------------------------------

### Gesture APIs

Source: https://github.com/moreswift/swift-cross-ui/blob/main/Sources/SwiftCrossUI/SwiftCrossUI.docc/Gestures.md

Documentation for gesture-related APIs in SwiftCrossUI, including tap gesture handling and hover detection.

```APIDOC
## View/onTapGesture(gesture:perform:)

### Description
Adds a tap gesture handler to a view. The gesture is recognized when the user taps the view, and the perform closure is called with the gesture value.

### Declaration
```swift
func onTapGesture(gesture: TapGesture, perform: @escaping (TapGesture.Value) -> Void) -> some View
```

### Parameters
- **gesture** (TapGesture) - Required - The tap gesture to recognize.
- **perform** (closure) - Required - The action to perform when the gesture is recognized. Receives the gesture value.

### Return Value
A view that triggers the action when the tap gesture is recognized.
```

```APIDOC
## TapGesture

### Description
A gesture that recognizes a tap (a quick touch and release).

### Declaration
```swift
struct TapGesture
```

### Overview
Use a `TapGesture` with the `onTapGesture(gesture:perform:)` modifier to handle tap interactions on a view.
```

```APIDOC
## View/onHover(perform:)

### Description
Adds a hover handler to a view. The perform closure is called when the pointer enters or leaves the view.

### Declaration
```swift
func onHover(perform: @escaping (Bool) -> Void) -> some View
```

### Parameters
- **perform** (closure) - Required - The action to perform when the hover state changes. Receives a Boolean indicating whether the pointer is hovering over the view.

### Return Value
A view that triggers the action when the hover state changes.
```

--------------------------------

### Package.swift: Add SwiftCrossUI and UIKitBackend dependencies

Source: https://github.com/moreswift/swift-cross-ui/blob/main/Sources/SwiftCrossUI/SwiftCrossUI.docc/Backends/UIKitBackend.md

Adds the SwiftCrossUI and UIKitBackend products as dependencies for the executable target named YourApp. This is required to use the UIKitBackend in your app.

```swift
// ...
let package = Package(
    // ...
    targets: [
        // ...
        .executableTarget(
            name: "YourApp",
            dependencies: [
                .product(name: "SwiftCrossUI", package: "swift-cross-ui"),
                .product(name: "UIKitBackend", package: "swift-cross-ui"),
            ]
        ),
        // ...
    ],
    // ...
)
```

--------------------------------

### Package.swift: Add SwiftCrossUI and AppKitBackend dependencies

Source: https://github.com/moreswift/swift-cross-ui/blob/main/Sources/SwiftCrossUI/SwiftCrossUI.docc/Backends/AppKitBackend.md

Declares the SwiftCrossUI and AppKitBackend products as dependencies for an executable target in a Swift package manifest.

```swift
// ...
let package = Package(
    // ...
    targets: [
        // ...
        .executableTarget(
            name: "YourApp",
            dependencies: [
                .product(name: "SwiftCrossUI", package: "swift-cross-ui"),
                .product(name: "AppKitBackend", package: "swift-cross-ui"),
            ]
        ),
        // ...
    ],
    // ...
)
```

--------------------------------

### Fix vcpkg build.ninja dirty error

Source: https://github.com/moreswift/swift-cross-ui/blob/main/Sources/SwiftCrossUI/SwiftCrossUI.docc/Backends/GtkBackend.md

Run these commands in Git Bash to fix the 'build.ninja still dirty after 100 tries' error caused by incorrect VM timezone.

```shell
$ cd C:\vcpkg
$ find . -type f -exec touch {} +
```

--------------------------------

### Generate SwiftCrossUI swiftinterface file manually

Source: https://github.com/moreswift/swift-cross-ui/blob/main/APITool/README.md

Command that APITool runs to generate a swiftinterface file for SwiftCrossUI. The resulting file is at .build/debug/SwiftCrossUI.build/SwiftCrossUI.swiftinterface.

```sh
swift build --target SwiftCrossUI -Xswiftc -emit-module-interface
```

--------------------------------

### Diff SwiftCrossUI and SwiftUI with APITool analyze

Source: https://github.com/moreswift/swift-cross-ui/blob/main/APITool/README.md

Manually run the API diff command. Requires macOS and Xcode. Use --developer-dir to specify a different developer directory than xcode-select --print-path.

```sh
# Diff SwiftCrossUI and SwiftUI. If you want to use a developer directory
# different to the one reported by 'xcode-select --print-path', then you
# specify one using the '--developer-dir' CLI option
swift run -c release APITool analyze --scui-checkout ..
```

--------------------------------

### Instrumenting your app with @HotReloadable and #hotReloadable

Source: https://github.com/moreswift/swift-cross-ui/blob/main/Sources/SwiftCrossUI/SwiftCrossUI.docc/Hot reloading.md

Instrument your main app file for hot reloading by importing SwiftBundlerRuntime, annotating the app with @HotReloadable, and wrapping the scene's content with #hotReloadable. The HotReloadable macro must be able to see the hotReloadable usage sites, so the app's body cannot be implemented in an extension.

```swift
import DefaultBackend
import SwiftCrossUI
import SwiftBundlerRuntime // 1.

@main
@HotReloadable // 2.
struct MyApp: App {
  // ...

  var body: some Scene {
    WindowGroup("MyApp") {
      #hotReloadable { // 3.
        Text("This is my app!")
      }
    }
  }
}
```

--------------------------------

### Regenerate porting kit generated files with APITool generate

Source: https://github.com/moreswift/swift-cross-ui/blob/main/APITool/README.md

Manually regenerate the generated files in ../Sources/_SwiftCrossUIPortingKit/Generated. Unlike the script, this does not format the files; run ../Scripts/format.sh on the generated directory to format them.

```sh
# Regenerate the porting kit's generated files
swift run -c release APITool generate --scui-checkout .. \
  ../Sources/_SwiftCrossUIPortingKit/Generated
```

--------------------------------

### Add WinUIBackend dependency in Package.swift

Source: https://github.com/moreswift/swift-cross-ui/blob/main/Sources/SwiftCrossUI/SwiftCrossUI.docc/Backends/WinUIBackend.md

Declare SwiftCrossUI and WinUIBackend as dependencies in your Package.swift manifest for a Windows executable target.

```swift
// ...
let package = Package(
    // ...
    targets: [
        // ...
        .executableTarget(
            name: "YourApp",
            dependencies: [
                .product(name: "SwiftCrossUI", package: "swift-cross-ui"),
                .product(name: "WinUIBackend", package: "swift-cross-ui"),
            ]
        ),
        // ...
    ],
    // ...
)
```

--------------------------------

### TODO comment with GitHub username

Source: https://github.com/moreswift/swift-cross-ui/blob/main/CONTRIBUTING.md

Use this format for new TODO comments. The comment must be tagged with your GitHub username, as shown with 'stackotter'.

```swift
// TODO(stackotter): Make this more robust once we have a state dependency
//   tracking system
```

--------------------------------

### Named link in documentation comment

Source: https://github.com/moreswift/swift-cross-ui/blob/main/CONTRIBUTING.md

Use named links to make documentation markdown line wrap at a sensible width.

```swift
/// For a detailed explanation, see Wikipedia's [page on parallel curves][wikipedia]. 
///
/// [wikipedia]: https://en.wikipedia.org/wiki/Parallel_curve
```

--------------------------------

### CastBackend macro signature

Source: https://github.com/moreswift/swift-cross-ui/blob/main/Sources/SwiftCrossUI/SwiftCrossUI.docc/AppBackend refactor.md

Use this macro to cast a backend to a more specific protocol inside View method implementations. It simplifies the boilerplate of dynamic casting and currently only works correctly within View methods.

```swift
@attached(body)
internal macro CastBackend<NewBackend>(
    backendGenericName: String? = nil,
    returnsWidget: Bool = false
)
```

--------------------------------

### Symbol link in documentation comment

Source: https://github.com/moreswift/swift-cross-ui/blob/main/CONTRIBUTING.md

Use double backticks to create a symbol link when referring to another symbol within the same target.

```swift
/// This method has been superceded by ``View/emphasized()``.
```

--------------------------------

### Patch libffi on macOS

Source: https://github.com/moreswift/swift-cross-ui/blob/main/Sources/SwiftCrossUI/SwiftCrossUI.docc/Backends/GtkBackend.md

Run this sed command to patch libffi when encountering libffi or FFI errors on macOS with older Xcode Command Line Tools.

```shell
$ sed -i '' 's/-I..includedir.//g' $(brew --prefix)/Library/Homebrew/os/mac/pkgconfig/*/libffi.pc
```

--------------------------------

### Break function parameters across multiple lines

Source: https://github.com/moreswift/swift-cross-ui/blob/main/CONTRIBUTING.md

Shows the preferred style for breaking function parameters across multiple lines: each parameter on its own line, with the closing parenthesis on its own line at ambient indentation level. The return type is placed on a new line.

```swift
func myFunctionWithLotsOfParameters(
    _ parameter1: Int,
    _ parameter2: Int,
    _ parameter3: Int,
    _ parameter4: Int
) async throws
    -> MyVeryLongReturnType<Int, String, [UInt8], MyErrorType>.Element
{
    // ...
}
```

--------------------------------

### Break long string literals with multiline string and backslash

Source: https://github.com/moreswift/swift-cross-ui/blob/main/CONTRIBUTING.md

Shows how to break a long string literal across multiple lines using a multiline string literal with backslashes at the end of each line except the last. The message appears as one line to the developer but is line-wrapped in the source file.

```swift
log.warning(
    """
    This is a very long warning with lots of context and detail to aid the developer \
    in resolving the issue that it's flagging. This message will appear as one line to \
    the developer but it line-wrapped within the source file, making things easier to \
    read as a SwiftCrossUI contributor.
    """
)
```
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