ARK-OS/arkos/arkrt/ark.ui.basic/Sources/SwiftCrossUI.docc/Backends/Gtk3Backend.md

Gtk3Backend

A secondary Linux backend built on top of Gtk3 (for older distros without Gtk4).

@Metadata {

@TitleHeading("Backend")
@Available(Gtk, introduced: "3")

}

Overview

This backend supports Linux, macOS and Windows (maybe?), but its support for non-Linux platforms is significantly worse than doc:GtkBackend's (due to underlying Gtk3 issues). Even on Linux, it's recommended to use doc:GtkBackend over Gtk3Backend where possible.

Warning: Non-Linux Gtk3Backend support is not a priority of this backend, and should only be used during development (e.g. to test your Linux UI natively on a Mac). There are multiple better choices of backend available on each non-Linux platform.

System dependencies

Before you can use Gtk3Backend you must install the required system dependencies for your platform.

Linux

Install the required dependencies using your system package manager:

@TabNavigator {

@Tab("Debian-based distros") {
    ```shell
    $ sudo apt install libgtk-3-dev clang
    ```
}
@Tab("Fedora-based distros") {
    ```shell
    $ sudo dnf install gtk3-devel clang
    ```
}

} If you are on a non-Debian, non-Fedora distro and the Gtk3Backend requirements end up differing significantly from the requirements stated above, please open a GitHub issue or PR so that we can improve the documentation.

macOS

$ brew install pkg-config gtk+3

If you don't have Homebrew, installation instructions can be found at brew.sh.

It should also be possible to use gtk+3 installed via MacPorts, but we have not tested that.

Windows

gtk3 installation has not been tested on Windows, and neither has Gtk3Backend, although there shouldn't be anything to stop it from working (🤞). Follow the gtk4 installation instructions from doc:GtkBackend and replace gtk with gtk3 in any vcpkg commands or vcpkg.json manifest files.

If you try this on Windows open a GitHub issue (even if it works without changes) so that we can fix any issues you faced and update this documentation.

Usage

@TabNavigator {

@Tab("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"),
                ]
            ),
            // ...
        ],
        // ...
    )
    ```
}
@Tab("YourApp.swift") {
    ```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()
            }
        }
    }
    ```
}

}