fluent-gpui

The estate's fork of GPUI (Zed's GPU UI framework) and a Fluent 2 design system on top of it, for native Windows and Linux desktop apps. Its consumers are rdpapp-client, rtbit-gpui, email-desktop-fluent and any later app that wants the same look and controls.

fluent-gpui is not affiliated with, endorsed by or sponsored by Microsoft. "Fluent" refers to the publicly documented Fluent 2 design language.

Status: re-fork in progress. The 3.x line replaces the old vendored GPUI copy with a filtered snapshot of current Zed main under vendor/zed/crates/*. That vendoring work is planned and not yet landed. Sections below describe the 3.x consumer contract; where something does not exist yet, it says so.

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1. Layering

  your app (rdpapp-client, rtbit-gpui, email-desktop-fluent, ...)
        │  depends on fluent-* crates only
        ▼
  fluent-app   fluent-layout   fluent-ribbon   fluent-primitives   fluent-core   fluent-test-utils
        │
        ▼
  vendored gpui closure   vendor/zed/crates/*   (gpui + the small set of Zed crates it needs,
        │                                        plus feature-gated estate patch modules)
        ▼
  upstream Zed (github.com/zed-industries/zed), pulled monthly

Rule: apps depend on fluent-* crates only, never on gpui directly. fluent-core re-exports the GPUI types apps need (elements, Context, Window, Render, styling helpers), so the GPUI version an app builds against is always the one the fluent crates were tested with. (The re-export is part of the 3.x work; until it lands, the examples still import gpui from the workspace.)

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2. How to reference it

fluent-gpui is distributed by git tag only. It is not published to crates.io. Tags have the form:

v<major>.<minor>.<patch>+zed.<short-sha>

where <short-sha> is the upstream Zed commit the vendored closure was cut from. Pin an exact tag on every fluent-* crate and use the same tag for all of them. Never pin a branch.

[dependencies]
fluent-core       = { git = "https://github.com/thedancingdeveloper/fluent-gpui", tag = "v3.0.0+zed.<short-sha>" }
fluent-primitives = { git = "https://github.com/thedancingdeveloper/fluent-gpui", tag = "v3.0.0+zed.<short-sha>" }
fluent-layout     = { git = "https://github.com/thedancingdeveloper/fluent-gpui", tag = "v3.0.0+zed.<short-sha>" }
fluent-ribbon     = { git = "https://github.com/thedancingdeveloper/fluent-gpui", tag = "v3.0.0+zed.<short-sha>" }
fluent-app        = { git = "https://github.com/thedancingdeveloper/fluent-gpui", tag = "v3.0.0+zed.<short-sha>" }
# Until fluent-core re-exports GPUI (see §1), the quick start imports gpui directly.
gpui              = { git = "https://github.com/thedancingdeveloper/fluent-gpui", tag = "v3.0.0+zed.<short-sha>" }

[dev-dependencies]
fluent-test-utils = { git = "https://github.com/thedancingdeveloper/fluent-gpui", tag = "v3.0.0+zed.<short-sha>" }

Replace <short-sha> with the value in the tag you are adopting (see the repository's tags and CHANGELOG.md). The first 3.x tag does not exist yet; this snippet is written against the integration branch and is verified against the real tag by the first-tag work item. Take only the crates you use.

Which crate for which need

Need	Crate
Theme, design tokens, colours, typography, motion, the GPUI re-exports	fluent-core
Buttons, inputs, dropdowns, checkboxes, switches, badges, cards, tooltips, date/time picker and other controls	fluent-primitives
Workspace shell, menus, context menus, dock panels, panes and splits, tree, data table, dialogs, toasts, command palette	fluent-layout
Ribbon command bar: tabs, groups, contextual tabs, overflow	fluent-ribbon
FluentApp entry point, title bar, client-side window chrome, bundled assets	fluent-app
Accessibility tree dumps and UI test helpers (dev-dependency)	fluent-test-utils

Feature flags

Estate renderer additions sit behind Cargo features so that the default build is close to upstream GPUI:

Feature	Gives you	When off
video-surface	GPU video texture allocation, upload and paint, for streaming RGBA frames (remote desktop, media)	The video API is not compiled; code that uses it fails to build, so gate your own use behind the same feature
backdrop-blur	backdrop_blur(radius, tint) acrylic-style backgrounds	Fluent surfaces fall back to a solid, tinted fill of the same colour. No error, no API change

Enable them on the crate that exposes them, for example fluent-core = { git = "...", tag = "...", features = ["backdrop-blur"] }.

Toolchain

The workspace pins its Rust toolchain in rust-toolchain.toml at each tag and states the MSRV as rust-version in the workspace Cargo.toml. The MSRV tracks what upstream GPUI needs; build your app with that toolchain or newer. (Both files arrive with the 3.x re-fork.)

Linux build dependencies (Debian/Ubuntu):

sudo apt-get install libxcb1-dev libxkbcommon-dev libxkbcommon-x11-dev libfontconfig-dev libwayland-dev libvulkan-dev

Without libfontconfig-dev, the build script for yeslogic-fontconfig-sys fails; alternatively set RUST_FONTCONFIG_DLOPEN=on to load fontconfig at runtime, but the link step still needs the -dev packages above.

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3. Platform support

Platform	Renderer	Accessibility	Status
Windows 10/11 x64	DirectX 11	UI Automation	Supported
Linux x64, X11 and Wayland	wgpu (Vulkan, GL fallback)	AT-SPI	Supported
macOS	Metal (upstream)	—	Not supported, not validated. Best-effort compile only. No video surface, no blur
Web / wasm	—	—	Not a target

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4. Quick start

The smallest app: a window with the Fluent title bar and one button.

use fluent_app::FluentApp;
use fluent_core::ThemeProvider as _;
use fluent_primitives::{Button, ButtonAppearance};
use gpui::{div, prelude::*, ClickEvent, Context, IntoElement, Render, Window};

struct Hello;

impl Render for Hello {
    fn render(&mut self, _window: &mut Window, cx: &mut Context<Self>) -> impl IntoElement {
        div()
            .size_full()
            .flex()
            .items_center()
            .justify_center()
            .bg(cx.theme().colors.surface)
            .child(
                Button::new("hello")
                    .label("Say hello")
                    .appearance(ButtonAppearance::Accent)
                    .on_click(|_: &ClickEvent, _, _| println!("hello")),
            )
    }
}

fn main() {
    FluentApp::new("Hello")
        .window_size(480.0, 320.0)
        .run(|cx| cx.new(|_| Hello));
}

FluentApp::run installs the theme, modal and toast hosts and the window title global, opens a frameless window with the Fluent title bar and resize chrome, and loads the bundled assets. Once fluent-core re-exports GPUI, the gpui:: import becomes fluent_core::gpui::.

To see every control, clone the repository and run the gallery:

cargo run -p gallery

Other examples: hello_world, widgets, form, demo_app.

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5. Versioning and cadence

• Every tag records the Zed commit it was cut from (+zed.<short-sha>).
• A new tag follows each monthly upstream pull, and each patch release (bug or security fix) in between.
• Breaking, for a consumer, means your app needs a source change to build or behaves differently after bumping the tag: a removed or renamed public item in a fluent-* crate, a changed signature, a changed feature flag, or a GPUI API change that leaks through the re-exports. Breaking changes bump the major version.
• Every tag has a CHANGELOG.md entry with migration notes for anything breaking. Read it before bumping.

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6. Accessibility

Every control exposes a role, an accessible name and its actions through AccessKit, which maps to UI Automation on Windows and AT-SPI on Linux. A control without them does not pass the accessibility gate described in CONTRIBUTING.md.

To check your own app, dump its accessibility tree in a test with fluent-test-utils and compare it with a committed snapshot (roles and names, not pixels). The gallery's own tree dump test is the worked example.

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7. Licence and attribution

• The fluent-* crates are licensed under the Apache License, Version 2.0.
• The vendored Zed crates under vendor/zed/ keep Zed's Apache-2.0 LICENSE-APACHE and NOTICE files. Their origin and the upstream commit are recorded in vendor/zed/UPSTREAM.md; the estate's changes to them are listed in vendor/zed/PATCHES.md. Only Apache-2.0-compatible Zed crates are vendored; no GPL or AGPL code is included.
• The Fluent 2 colour token structure was adapted from aernom/fluent-ui-gpui (MIT).

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8. Pointers

• CONTRIBUTING.md — for maintainers: upstream pulls, the patch set, the accessibility gate (coming with the 3.x work).
• AGENTS.md — for worker sessions (coming with the 3.x work).
• docs/graft.md — how changes land in this repository.
• docs/VISUAL_TARGETS.md — visual reference targets.
• CHANGELOG.md — release notes and migration notes.