lux

lux is a GPU-accelerated UI framework for Go built on the Elm architecture. It combines a deterministic, single-threaded app loop with a modern rendering stack (wgpu/Vulkan/Metal/D3D12) and first-class support for accessibility, animations, and embedded/bare-metal targets.

go get github.com/timzifer/lux

Requires Go 1.25+.

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Features

• Elm architecture — pure update(model, msg) → model and view(model) → Element; no data races possible
• GPU rendering — wgpu (Vulkan / Metal / D3D12 / WebGPU) with OpenGL 3.3 fallback
• CSS-compatible layout — Flexbox, CSS Grid, and HTML Table algorithms
• Animation system — deterministic, frame-driven Anim[T] and spring physics; no goroutines
• Design token theming — LuxDark / LuxLight built in; fully customisable
• Rich widget catalogue — 20+ widgets (buttons, forms, navigation, data, menus, dialogs)
• Six platform backends — GLFW · Win32 · Cocoa · X11 · Wayland · DRM/KMS
• Accessibility — Windows UIA · macOS NSAccessibility · Linux AT-SPI2 (pure-Go D-Bus)
• i18n / RTL — BCP 47 locale propagation, Unicode BiDi & line-breaking, grapheme-aware cursor

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Quick Start

package main

import (
    "fmt"
    "log"

    "github.com/timzifer/lux/app"
    "github.com/timzifer/lux/theme"
    "github.com/timzifer/lux/ui"
    "github.com/timzifer/lux/ui/button"
    "github.com/timzifer/lux/ui/display"
    "github.com/timzifer/lux/ui/layout"
)

// 1. Define your model.
type Model struct{ Count int }

// 2. Define your messages.
type IncrMsg struct{}
type DecrMsg struct{}

// 3. Pure update function — no side effects, no locks.
func update(m Model, msg app.Msg) Model {
    switch msg.(type) {
    case IncrMsg:
        m.Count++
    case DecrMsg:
        m.Count--
    }
    return m
}

// 4. Pure view function — returns an Element tree.
func view(m Model) ui.Element {
    return layout.Column(
        display.Text(fmt.Sprintf("Count: %d", m.Count)),
        layout.Row(
            button.Text("-", func() { app.Send(DecrMsg{}) }),
            button.Text("+", func() { app.Send(IncrMsg{}) }),
        ),
    )
}

func main() {
    if err := app.Run(Model{}, update, view,
        app.WithTheme(theme.Default),
        app.WithTitle("Counter"),
    ); err != nil {
        log.Fatal(err)
    }
}

Run it:

go run ./examples/counter/

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Documentation

Document	Description
Getting Started	Installation, prerequisites, annotated walkthrough
Elm Architecture	Model / Update / View / Cmd in depth
Architecture	Package map, rendering pipeline, app loop internals
Widget Catalogue	All widgets with API reference
Layout	Flexbox, CSS Grid, Table, Box, Stack, RTL
Theming	Design tokens, built-in themes, custom themes
Animation	Anim[T], spring physics, easing, AnimGroup/AnimSeq
Drawing API	draw.Canvas reference
Input & Events	Keyboard, mouse, touch, IME, shortcuts
Testing	Golden-file scene tests with uitest
Platform Backends	Backend selection and configuration
Accessibility	AccessTree, UIA, AT-SPI2, NSAccessibility
Advanced
Custom Widgets	Implementing the Widget interface
State Persistence	Save/restore app state across restarts
RFC Index	Internal design documents

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Examples

go run ./examples/counter/       # simple counter with theme toggle
go run ./examples/kitchen-sink/  # comprehensive widget showcase
go run ./examples/fenster/       # window management

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Platform Support

Platform	Backend	GPU	Notes
Windows 10+	Win32 native / GLFW	Vulkan · D3D12
macOS 11+	Cocoa / GLFW	Metal
Linux (X11)	X11 / GLFW	Vulkan · OpenGL
Linux (Wayland)	Wayland / GLFW	Vulkan · OpenGL
Embedded / bare-metal	DRM/KMS	Vulkan · OpenGL	Raspberry Pi, industrial HMI

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Architecture Overview

┌─────────────────────────────────────────────┐
│                 app package                 │  ← Elm loop, messages, commands
│  Run(model, update, view, opts...)          │
└──────────────┬──────────────────────────────┘
               │ Element tree
┌──────────────▼──────────────────────────────┐
│               ui package                   │  ← Widget system, layout, focus,
│  Widget → Render → reconcile → layout      │     gestures, accessibility tree
└──────────────┬──────────────────────────────┘
               │ draw.Canvas commands
┌──────────────▼──────────────────────────────┐
│           internal/render                  │  ← Scene graph, batching,
│           internal/gpu (wgpu)              │     GPU upload, wgpu backend
└──────────────┬──────────────────────────────┘
               │ native window / surface
┌──────────────▼──────────────────────────────┐
│            platform package                │  ← GLFW · Win32 · Cocoa ·
│  Init · Run · Events · Clipboard           │     X11 · Wayland · DRM/KMS
└─────────────────────────────────────────────┘

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Contributing

Design decisions are captured in the RFC documents. Start there before opening a pull request for a new subsystem. See CONTRIBUTING.md for build, test, and PR conventions, and SECURITY.md for reporting vulnerabilities.

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License

lux uses a dual-license model:

• Noncommercial use (personal projects, hobbyists, research, education, nonprofits): free of charge under the PolyForm Noncommercial License 1.0.0.
• Commercial use requires a paid commercial license. See LICENSING.md for details and how to get in touch.

Third-party components bundled under vendor_gogpu_wgpu/ retain their own licenses; see NOTICE for attribution details.