kui

kui is a UI library for Rust. You describe what is on screen as a tree of boxes and text; kui lays it out, draws it, and hands back what the user did as plain data. Underneath is a clay-style flat-array layout solver, on top an iced-style view / on_event loop, and text shaping is part of the core. Because a frame is data all the way down, Lua, C and Node bind to the same contract the Rust builders use.

Crates

crate	role
kui-native	The crate most apps use: a window (winit), the GPU renderer, the stock widgets and the App trait	crates.io · docs.rs
kui-core	The bindable contract: the flat per-frame tree, the flex solver, the text stack (cosmic-text + a glyph atlas), events as data, resources, the quad display list	crates.io · docs.rs
kui-wgpu	The wgpu backend: one instanced pipeline (rounded rects, borders, glyphs), one draw call per frame	crates.io · docs.rs
kui-derive	#[derive(Message)]: an enum that travels through the frame as data and comes back typed	crates.io · docs.rs
kui-lua	Lua extensions via mlua: scripts return table trees and receive events as tables	crates.io · docs.rs
kui-ffi	The C API (a cdylib, a staticlib on request, plus include/kui.h): flat builder calls, opaque KuiValue payloads, repr(C) draw data, a windowed runner via callbacks, and CExtension, a C shared library as a guest in another host's frame	crates.io · docs.rs
kui-node	The Node.js addon (napi-rs) behind the @qxuken/kui npm package: JSX views lowered into the IR in one call per frame, Elm-style messages as data. Ships through npm, not crates.io	packages/kui

Install

cargo add kui-native

which writes the one line a project needs:

[dependencies]
kui-native = "0.1.0-alpha.44"

Every release so far is an alpha. A requirement like "0.1.0-alpha.34" is a floor that admits every later alpha; Cargo.lock keeps the version you tested, and "=0.1.0-alpha.34" pins it in the manifest.

macOS and Windows need nothing beyond a Rust toolchain. On Linux the build wants pkg-config and ALSA's headers (libasound2-dev on Debian and Ubuntu). A window loads the rest at run time: libxkbcommon (plus libxkbcommon-x11 on X11), the X11 client libraries (libX11, libXcursor, libXrandr, libXi) or libwayland-client, and libvulkan with a driver or libEGL. A missing one fails when the window opens, with the library's name in the error. File dialogs go through the XDG desktop portal; without one on the session bus, every dialog answers as if cancelled.

The first build takes a few minutes: it compiles a GPU renderer.

Hello, window

The whole of kui in one program. An app is a type with a view that declares the frame from scratch, and a launcher opens a window around it.

use kui_native::{App, TextStyle, Ui};

/// The app is any type. It holds the state; this one has none yet.
struct Hello;

impl App for Hello {
    /// Called once per frame. Everything on screen is declared here,
    /// from scratch, every time.
    fn view(&mut self, ui: &mut Ui<'_>) {
        let theme = ui.theme();
        ui.text("Hello, kui", TextStyle::new(24.0).color(theme.fg));
    }
}

fn main() -> Result<(), Box<dyn std::error::Error>> {
    kui_native::app("Hello").size(360.0, 200.0).run(Hello)
}

Put that in src/main.rs and cargo run. From a checkout of this repository it is cargo run -p kui-native --example tutorial_01_hello.

That program is step one of the kui book: ten short chapters, each the last plus one concept (layout, messages, controls, lists, keys, floats, motion, effects, a test), and each a program under examples/rust/tutorial. Read it first.

Documentation

• The kui book: the path in, one concept a chapter, every code block pulled from a runnable program. Its source is docs/book.
• API reference on docs.rs: kui-native, kui-core, kui-wgpu, kui-derive, kui-lua, kui-ffi.
• docs/howto.md: "How do I…", about twenty questions a developer arrives with, two sentences each and a pointer.
• docs/props.md: every prop, element, event, warning, theme role and metric, with its JSX, Lua, C and Odin spelling in the same row. Generated from the schema, so it cannot drift.
• examples/README.md: the map of every example in Rust, C, Lua, Node and Odin, what each shows and how to run it.
• docs/guide.md: testing without a window, the devtools panel, the same app from Node, Lua and C, and the reference documents in detail.
• docs/design.md: the design notes (one schema for every binding, events, focus, modals, transitions, text, windows, audio, the C ABI) and the layout solver pass by pass.
• docs/performance.md: the benchmark table and what it says, editing latency, frame pacing.
• docs/releasing.md: the registries, how a release is cut, CI, the smoke rounds and the audits.
• docs/status.md: what v0 does not do, by area.
• docs/adr: design records, the decisions that are hard to reverse and would look arbitrary without their context.
• CHANGELOG.md: per release, what was added and, separately, what an app can delete.
• packages/kui: the Node package, @qxuken/kui: JSX views, an Elm-style update, a headless createApp and the same devtools.

License

MIT, see LICENSE.