Starling

starling.build

A new Linux desktop environment, whose shell, compositor, framework, and apps are written in Swift (the framework is a full port of Flutter's Dart framework to Swift — no Dart VM). It brings its own Wayland compositor and its own X11 server, so it runs native Wayland clients and X11 apps alike. Runs on the Flutter engine's C core via the sibling repo starling-engine.

sdk/     the Flutter→Swift framework port (SwiftPM package "FlutterSwift")
shell/   the desktop shell: compositor (C Wayland server), window manager,
         dock, spaces, portals — SwiftPM package "DesktopShellApp"
apps/    first-party apps (Settings, Files, Terminal, …), one SwiftPM package each
build/   packaging: the Ubuntu .deb, session files, app-run/app-install tools,
         vendored flutter_assets
docs/    porting guides and design notes

Get started: Install Starling · User Guide · Build from source

Status

Early development — version 0.2.1. The desktop boots as a real session, runs its own compositor and apps, and installs from a .deb on a stock Ubuntu 26.04. It is also the work of one person and a few months, so expect rough edges, missing pieces, and bugs. Nothing here is load-bearing for anyone yet, and interfaces change without notice.

What follows is deliberately specific about what is and is not done, because "a desktop environment" invites assumptions that would be wrong.

What works

Area	State
Session	Boots through the normal login path — gdm3 → gdm-wayland-session → /usr/libexec/starling-session → DesktopShellApp --drm. Unprivileged: DRM master and input come from logind via libseat, not from running as root.
Display	DRM/KMS modeset, GBM/EGL, hardware cursor, flip-driven frame pacing, multi-output layout. Tested on AMD (Radeon 780M) and on virtio-gpu/virgl in a VM.
Compositor	~5,700 lines of C implementing xdg-shell, linux-dmabuf (zero-copy import), viewporter, fractional-scale-v1, pointer-constraints, relative-pointer, text-input-v3, presentation-time, primary-selection, idle-inhibit, cursor-shape-v1, xdg-decoration, xdg-activation, xdg-output, wlr-data-control.
Window management	Floating and tiling (master-and-stack) behind one switch, spaces with a Mission Control overview, drag-move and drag-resize, a dock with running indicators and drag-to-reorder, and a Launchpad.
Apps	Settings, Files, Terminal (a real PTY), Calculator, App Store — five first-party apps, all written against the Swift framework port.
Portals	xdg-desktop-portal implementing Settings, FileChooser (OpenFile/SaveFile/SaveFiles, via a helper window) and Request.
Third-party clients	Launch and render as native Wayland clients: Chrome, VS Code, Slack, Discord, Teams, Telegram, IntelliJ IDEA, GIMP, Blender, GNOME Web, GNOME Text Editor — covering Chromium/Electron, Qt6, GTK3, GTK4, the JetBrains Runtime's Wayland toolkit, and Blender's own GHOST, which drives the viewport (EEVEE included) through our linux-dmabuf. Both buffer paths are live: GPU clients via linux-dmabuf, software clients via wl_shm. Zoom runs with a caveat (below). X11 clients run against the in-tree X server (DRI3/Present).
Packaging	A 52.8 MB .deb that installs on a minimal 26.04 image, pulling 26 dependency packages; Depends is computed from the shipped binaries by dpkg-shlibdeps.
Framework port	137 test files under sdk/Tests.

Known limitations

• xdg_output state is sent once and never updated. A client that asks for an xdg_output gets the logical position and size as they are at that moment; a later mode change, scale change or output hotplug does not re-send them, so a long-running client can be left with stale geometry. The resources are not tracked per output, which is what fixing it needs.
• The portal is incomplete. Settings and FileChooser work — GTK4 reads org.freedesktop.appearance through them, and both carry the version property clients probe first — but Inhibit, ScreenCast, Camera and Print are absent entirely. The session bus masks the stock xdg-desktop-portal rather than letting it fill those gaps: it has no backend for Starling, so it would serve only its backend-less interfaces while taking org.freedesktop.portal.Desktop away from the shell's own portal, breaking the two that do work.
• Settings' Notifications toggle does nothing — there is no notification service behind it yet.
• No screen lock or screensaver.
• Scaling is effectively pinned to 2.0. Fractional values produced blurry text and are not usable yet.
• No display-mode selection. The session takes the connector's preferred mode; overriding it means editing the session launcher.
• The third-party app runtime is opt-in and unshipped. app-run expects a debootstrap'd runtime under /var/lib/starling-apps; third-party apps are otherwise expected to use their native packaging.
• Not every in-tree app ships. Text Editor and Image Viewer build but are not packaged; the video player was removed because Ubuntu's FFmpeg build carries GPL parts.
• The App Store catalog is small, and its tiles are deliberately generic. Ten entries, all of which install and launch: Chrome and VS Code were driven through the store's own buttons, the other eight through app-install and app-run — the paths those buttons invoke. Tiles use category glyphs rather than vendor artwork on purpose: those logos are their owners' trademarks and Starling ships none of them. Chrome and VS Code do show their real icons in the launcher and dock, read from the host at runtime; the rest fall back to a generic glyph, since only those two ids are wired to that lookup.
• One catalogued app runs with a caveat. Zoom starts but complains no pactl and pacmd found — nothing in the package pulls in an audio stack, and no first-party app needs one yet.
• No CI. Testing is the framework's unit tests plus manual verification in a VM.

Roadmap

Direction, not commitment:

• Run the Linux apps people actually use. The major toolkits composite today — Chromium/Electron, Qt6, GTK3 and GTK4 — and X11 clients run against the in-tree X server. The bar is that an app installed from your distribution simply works, so the remaining work is breadth and the rough edges each app exposes, not a missing toolkit.
• Android apps, through Waydroid. The launcher and app registry already carry entries for it.
• Windows apps, through Wine or Proton, once the Linux story is solid.
• More hardware. Verified on AMD and on virtio-gpu so far; Intel and NVIDIA next, then laptop concerns — lid, backlight, output hotplug — and HiDPI.
• More platforms. Distributions beyond Ubuntu 26.04, and ARM alongside x86-64.
• The desktop's own basics, so it holds up as a daily driver: notifications, screen lock, display settings, and enough of the framework port to build them comfortably.
• Stay current with upstream Flutter. The engine fork is arranged so rebasing onto a new release is ordinary git rebase.

Setup

Building both halves on a machine that has neither — toolchains, gclient, apt packages, timings, and the Ubuntu 26.04 workarounds — is docs/BUILDING.md. The short version follows.

Clone starling-engine next to this repo (a built one — see its README), then:

./bootstrap.sh            # creates the `engine` symlink -> ../starling-engine/engine

Every engine reference (bridge headers, libflutter_engine.so, libflutter_linux_drm.so, icudtl.dat) goes through that symlink; point it at any engine checkout with ./bootstrap.sh <path>.

Build

cd shell && swift build -c release          # the shell (+ sdk as dependency)
cd apps/TerminalApp && swift build -c release   # each app is its own package

Engine C++ changes rebuild in the engine repo (ninja -C engine/src/out/...); the shell needs no relink — it binds only the engine's stable C API.

Run

build/run-desktop.sh

Stages everything into one self-contained tree and runs the desktop from it — the same layout the package installs, so the dev loop exercises the shipping configuration. Needs the GPU free (no display manager or compositor). Uses the distro's Mesa; takes the unprivileged libseat path when a seat manager is reachable, else sudo. --no-stage reuses the existing .stage/.

Drive it and take screenshots with sudo build/shell-drive.py "dock settings" click "shot /tmp/x.png" (run with no args for the action list).

Do not run straight out of .build: child apps are spawned with LD_LIBRARY_PATH scrubbed and resolve libraries through their own $ORIGIN, so they only work when the libraries sit next to them — which is what staging does.

Package

build/stage.sh [outdir]               # the assembled tree (defaults to .stage/)
build/package-desktop.sh [outdir]     # -> starling-desktop_<ver>_amd64.deb

stage.sh is the single definition of the layout; package-desktop.sh wraps its output with control metadata, the polkit policy, and the session entry. Prereqs: shell + apps built (swift build -c release), engine host_release built. The deb installs under /usr/lib/starling + /usr/share/starling and adds a "Starling" session to the login screen.

Packages are maintained as Starling <dev@starling.build> — the same project identity every commit here uses. Use it rather than a personal address for the Maintainer: field and anywhere else the project needs a contact.

Provenance

This repo starts from a fresh snapshot, with no history before it. The code was developed in two private repos and re-imported here: the framework port and shell came from a working branch (flutter_swift/ → sdk/, apps/DesktopShellApp/ → shell/, apps/* → apps/), the packaging tools from a second one. Neither is public, so the pre-import history is not reachable — everything since is in this repo's log.

The framework port under sdk/ is a derivative of Flutter and keeps Flutter's licence — see sdk/LICENSE. The C++ half lives in starling-engine, a fork of flutter/flutter whose starling branch carries the Starling delta on top of real upstream history.

Credits

Starling is a small amount of new code sitting on a great deal of other people's work. Named here with thanks — the legally required attributions are in NOTICE, but these deserve saying out loud:

• Flutter — the engine Starling runs on, and the framework design sdk/ is a port of. The embedder API is a genuinely well-drawn seam: it let a desktop shell supply its own surface, input and vsync without forking the renderer. Skia and Impeller do the drawing; Dart's tooling built the assets.
• Wayland and wayland-protocols — the compositor implements these. Kristian Høgsberg, Collabora, Intel, Red Hat, Samsung, Purism, Simon Ser, Jonas Ådahl, Kenny Levinsen and others wrote the protocol definitions in shell/Sources/WaylandServer/*-protocol.c.
• Mesa — EGL, GBM and the gallium drivers; every frame Starling puts on screen goes through it.
• libinput, libseat/seatd, libxkbcommon, libdrm, libevdev — Peter Hutterer, Kenny Levinsen and the freedesktop.org maintainers. libseat in particular is why the desktop runs unprivileged instead of as root.
• Swift — the language, and the corelibs Foundation, Dispatch and Observation the whole tree is written against.
• FreeType, HarfBuzz and ICU — text rendering and internationalisation, bundled inside the engine.
• PDFium — PDF rendering in the Image Viewer.
• Roboto Mono and Cupertino Icons for the typefaces and glyphs, and Daniel Lloyd Blunk-Fernández for the Golden Gate photograph the desktop ships as its wallpaper, via Unsplash.
• Debian and Ubuntu — the packaging conventions this ships under, and the distribution it is developed and tested on.

Starling's own contribution is the DRM/KMS embedder, the Wayland compositor, the Swift port of the framework, and the shell and apps built on top. None of it would exist without the above.

Licensing

Starling's own code is Apache-2.0 (LICENSE). Two subtrees keep their upstream license instead, because they are ports and forks rather than original work — matching upstream keeps rebasing and contributing back possible:

Path	License
shell/, apps/, build/, docs/	Apache-2.0 — © the Starling authors
sdk/	BSD-3-Clause — © the Flutter Authors (sdk/LICENSE)
shell/Sources/WaylandServer/*-protocol.{c,h}	MIT — generated from wayland-protocols XML; the upstream copyright sits in each file
sibling starling-engine	BSD-3-Clause — a Flutter engine fork

NOTICE lists the third-party components the binaries redistribute — the Swift runtime, the Flutter engine and its bundled libraries, fonts, and the wallpaper. The .deb ships it as /usr/share/doc/starling-desktop/copyright.

No third-party application artwork is shipped: those logos are their owners' trademarks. When such an app is installed, the launcher reads its icon from the host at runtime via the freedesktop lookup, recorded into the app registry at install time (registry/); otherwise the shell draws its own generic glyph.

Apache-2.0 is not GPLv2-compatible, which costs nothing today: the shipped desktop links no GPL code at all (MIT/BSD, dynamically-linked LGPL for glibc and sd-bus, and the GCC runtime under its Runtime Library Exception).