UI toolkit for Linux in Swift. Powered by Vulkan


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AppKid is an open-source Application Development Framework heavily inspired by Apple's AppKit and UIKit. It was started as a way to have convenient SDK to build UI applications for X11 enabled GNU/Linux environment. The framework written completely in Swift, using Vulkan as rendering backend and relies on X11 for window management and user input events.

Hello World with AppKid

import AppKid
import Foundation

class RootViewController: ViewController {
    override func viewDidLoad() {
        let label = Label(frame: CGRect(x: 0.0, y: 0.0, width: 320.0, height: 44.0))
        label.text = "Hello World"
        view.addSubview(label) = CGPoint(x: 160.0, y: 120.0)

final class AppDelegate: ApplicationDelegate {
    func application(_: Application, didFinishLaunchingWithOptions _: [Application.LaunchOptionsKey: Any]? = nil) -> Bool {
        let window = Window(contentRect: CGRect(x: 0.0, y: 0.0, width: 320.0, height: 240.0))
        window.title = "Hello World"
        window.rootViewController = RootViewController()
        return true

Getting started with AppKid in your project

AppKid depends on mulitple opensource projects. Below are the instructrions on how to set those up for Debian-based Linux distributions. RPM-Based instructions will be added some time later.

  • Swift language
    • Get tarball package from, unpack it to some system directory like /opt/swift and update global $PATH variable

       sudo nano /etc/profile.d/

      paste this

       export PATH=/opt/swift/usr/bin:"${PATH}"`

      where /opt/swift is a path to your swift toolchain

    • Alternatively install swiftlang package via swiftlang builds (does not require extenting $PATH variable)

       wget -qO - | sudo bash
       sudo apt install swiftlang -y
  • Vulkan SDK
    • Vulkan SDK from LunarG repository LunarG is using deprecated apt-key to verify signature so this repo provides more modern and safe configuration via SupportingFiles
       wget -qO - | gpg --dearmor | sudo tee -a /usr/share/keyrings/lunarg-archive-keyring.gpg
       sudo wget -q -O /etc/apt/sources.list.d/lunarg-vulkan-jammy.list
       sudo apt update
       sudo apt install -y vulkan-sdk
    • Alternativelly you can try to install Vulkan SDK from tarballs provided by LunarG or if you are using Debian 12 and newer or Ubuntu 23.04 and newer you can substitute Vulkan SDK from LunarG by installing packages form distro's repository
       sudo apt install -y \
       	libvulkan-dev \
       	vulkan-validationlayers \
      But you will have to manually install glslc compiler from Gooogle's shaderc project located here.
  • System libraries
     sudo apt install -y \
     	libx11-dev \
     	libxi-dev \
     	libwayland-dev \
     	libcairo2-dev \
     	libpango1.0-dev \
  • libclang for shaders preprocessing

    NOTE: This is now a required dependency since shader compilation is now part of the pipeline

    AppKid is using its own GLSL dialect for internal shaders. It is preprocessed via custom tool that is build on top of libclang.

    Install libclang itself

     sudo apt install -y \

    Install provided package config file for libclang because llvm does not provide one:

     sudo mkdir -p /usr/local/lib/pkgconfig
     sudo wget -q -O /usr/local/lib/pkgconfig/clang.pc

    If you are going to install different version of libclang - adjust clang.pc accordingly.

  • libpython3.8 for debugger support

    NOTE: If you have no intention of debugging Swift code you skip this step

    Swifts LLDB is built using libpython3.8. On modern system you will probably meet libpython3.9 or higher. Just make a symbolic link from new version to old version. Tho this is not ideal and will break with every major distribution update for you

     cd /usr/lib/x86_64-linux-gnu
     sudo ln -sf

    where is currently installed version and is filename against which Swifts LLDB was built.

After the necessary dependencies were set up just add this package in your SwiftPM manifest file as a dependency and add AppKid product as a dependency to your target:

// swift-tools-version: 5.8
import PackageDescription

let package = Package(
  name: "MyApp",
  dependencies: [
	  url: "", 
	  branch: "main"
  targets: [
      name: "MyApp",
      dependencies: [
        .product(name: "AppKid", package: "AppKid")


Contributions are very welcome. Before you dive in it is recommended to setup your local development environment.

You can use provided sample application called AppKidDemo, it is located in this repository and is one of the products. AppKidDemo is written in swift and provides a sample environment for AppKid development.



Before jumping straight into writing code there is some development setup required. Below are instructions on how to setup development environment for Debian-based Linux or for macOS

Debian-based Linux


  • Xcode via AppStore or

  • XQuartz
    brew install xquartz
  • Vulkan SDK via

  • PKG_CONFIG_PATH global variable

    Update global PKG_CONFIG_PATH variable so command line tools would have proper pkg-config search path:

     sudo nano /etc/profile

    paste this:

     export PKG_CONFIG_PATH="/opt/X11/lib/pkgconfig:/usr/local/lib/pkgconfig:/usr/local/lib:$PKG_CONFIG_PATH"

    Add a launchctl agent that will update environment variables per user session so Xcode could find all the pkg-config files needed to properly build projects:

     mkdir -p ~/Library/LaunchAgents
     curl -s -o ~/Library/LaunchAgents/environment.plist
     launchctl load -w ~/Library/LaunchAgents/environment.plist

    NOTE: This file is not backed up by TimeMachine, so you probably want to extend this environment variable for command line tools in some other way

  • Install other project dependencies:
     brew install \
     	pkg-config \
     	cairo \
     	glib \

Building and running

All projects in this repository are using Swift Package Manager exclusivelly. This means that building top level product is as easy as this

NOTE: Since this is a monorepo for multiple projects at the moment it is recommended to use dedicated build directories by adding --build-path argument to swift commands

WARNING: Running of apps built with AppKid on macOS is not possible and there's no plan to make it so

swift build --product AppKid

Same with running

swift run --product AppKid

There are additional scripts under Utilities directory with pre-defined building, running, cleaning and other commands.

WARNING: Building on macOS is broken at the moment because of the issue of using vulkan-sdk as C library in pure swift project


On Linux the recommended way to write code is to use VSCode or VSCodium IDE. This way you'll get preconfigured LLDB configuration to build and run the AppKidDemo, full integration with Swift SourceKit LSP for syntax highlight, symbol navigation, automcompletion just like in Xcode and much more. It's just convenient.

On macOS there is a choice between VSCode/VSCodium and Xcode.I recommend generating the Xcode project via swift package generate-xcodeproj and opening it because indexing and build target generation is just faster this way, but you can also open Packge.swift in Xcode and it will be pretty much the same user experience.

The generate-xcodeproj from swift package manager is deprecated. It does not receive updates anymore and is throwing a fatal error when it meets a plugin definition in Package.swift file. Opening Package.swift itself does not work really well anymore either as it's just not showing any of the local submodules in Xcode sources tree.

There is a carefully crafter VSCode/VSCoium configuration provided in the root of the reporisotory, including launch configuration and a bunch of tasks for things like regenerating Vulkan entities interface conformance from Vulkan spec or rebuilding ContentAnimation shaders. For the best experience in VSCode/VSCodium it is highly recommended to install following extensions:


The code in this repository is distributed under Apache-2.0. Please check Contributing before creating a pull request


AppKid is making use of the following opensource projects:


  • Swift Tools 5.8.0
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Last updated: Sat Jul 06 2024 15:02:12 GMT-0900 (Hawaii-Aleutian Daylight Time)