Repose

A small, composable UI toolkit in Rust with a Compose-like API, cross-platform runners (desktop/Android/web), and a WGPU renderer.

Status: pre-1.0. API (mostly minor) might change. A few working apps exist, and there shouldn't be any major issues.

Useful for simple apps (though aiming for bigger ones in the future), and for developers who want a Compose-like experience in Rust without the overhead of embedding a web view or maintaining separate native UI codebases.

Features

• Declarative UI — Compose-like API with View functions, reactive Signals, and remember for state
• Cross-platform — Desktop (winit), Android, and WebAssembly
• Layout — Flexbox and Grid via Taffy
• Rendering — Rectangles, borders, rounded clips, ellipses, text, images via WGPU
• Text — Shaping, metrics, and wrapping via cosmic-text with caching
• Input — Pointer events, scrolling, focus traversal, IME support
• Widgets — Text, Button, TextField, Checkbox, Switch, Slider, ScrollArea, LazyColumn
• Navigation — Typed stack navigation with transitions (repose-navigation)
• Accessibility — AccessKit integration on desktop, semantic node pipeline
• DevTools — Inspector overlay (Ctrl+Shift+I)

Non-Goals

• Full feature parity with mature toolkits (will need funding, with years of usage)
• Accessibility coverage on all platforms (in progress)
• Multi-window (native, until a better alternative to winit comes up, which wouldn't happen anytime soon) and complex popup systems

Quick Start

Prerequisites

• For desktop: system dependencies for WGPU (varies by OS)
• For web: trunk (cargo install trunk)
• For Android: Android SDK/NDK and cargo-apk

Run the Showcase

Desktop:

cargo run -p showcase --features desktop-bin

Web:

cd examples/showcase
trunk serve

Or try the hosted demo.

Android:

cd examples/showcase
cargo rapk run --target aarch64-linux-android --lib

Usage

use repose_core::prelude::*;
use repose_ui::*;

fn Counter() -> View {
    let count = remember_state(|| 0);
    
    Column(Modifier::new().padding(16.0)).child((
        Text(format!("Count: {}", *count.borrow())),
        Button("Increment", {
            let count = count.clone();
            move || *count.borrow_mut() += 1
        }),
    ))
}

fn main() -> anyhow::Result<()> {
    repose_platform::run_desktop_app(|_sched, _ctx| Counter())
}

State management:

// Signal for shared/global state
let theme = signal(Theme::default());
theme.set(Theme::dark());

// remember_state for component-local state
let input = remember_state(|| String::new());

// Derived state
let full_name = produce_state("full", {
    let first = first_name.clone();
    let last = last_name.clone();
    move || format!("{} {}", first.get(), last.get())
});

Layout:

Row(Modifier::new().gap(8.0)).child((
    Text("Left"),
    Spacer(),
    Text("Right"),
))

Navigation:

let stack = remember_back_stack(Route::Home);
let navigator = Navigator { stack: (*stack).clone() };

// Push route
navigator.push(Route::Details);

// Pop (back button)
back::set(Some(Rc::new(move || navigator.pop())));

GIF

Inspiration

Wanted an UI which was short and easy to understand by looking at the code (essentially declaritive, helps balance out rust ig :), similar to Compose, and liked the design of Jetpack Compose too (like Iced, which was, similarly, based on elm-ui)

Architecture

Projects Using Repose

These were built to test the toolkit in real apps:

• startpose — Web startpage
• wifi-exporter — Android WiFi importer/exporter
• soredowe — Linux pacman UI

Contributing

Issues and PRs are welcome, especially for:

• Correctness bugs
• Performance regressions (include a repro)
• Platform gaps (except external issues like Android IME, if documented)

Development Setup

git clone https://github.com/mlm-games/repose
cd repose
cargo test --workspace

Support

Consider donating if you'd like to support it's development. Open an issue or a discussions for bugs or questions.

For commercial licensing (LGPL-2.1 is the default), open an issue to discuss.

Mentions

• Taffy for layout
• cosmic-text for text shaping
• wgpu for cross-platform graphics
• AccessKit for accessibility
• Heavily inspired by Jetpack Compose's API design

License

See LICENSE.