GUI

An immediate-mode UI framework for V that stays out of your way.

Windows native support is under active validation. The current documented path uses native Windows with MSVC/vcpkg and is tracked in docs/WINDOWS.md; this is not yet a claim of full Windows parity.

Motivation

Most UI frameworks want you to think about data binding, observables, and UI thread synchronization. v-gui doesn't. Your view is just a function of your state—change the state anywhere and the UI updates. No wiring. No callbacks to remember. No threading headaches.

The layout engine is inspired by Clay, a fast layout algorithm that makes flex-box style layouts simple to reason about.

V is a simple language. It deserves a simple UI framework.

Who Is This For?

Good fit if you want:

• State as plain structs, no observables
• Thread-safe UI updates from anywhere
• Code-defined layouts (no XML, no designers)
• Desktop apps, tools, data viewers, games

Maybe not if you need:

• Mature accessibility support (work in progress)
• Production mobile apps
• Native platform widgets
• Drag-and-drop UI designers

Features

Layout

• Flex-box rows and columns
• Fit/fill/fixed sizing per axis
• Scroll containers with momentum
• Nested layouts to any depth

Widgets (30+)

• Text, inputs, textareas
• Buttons, toggles, switches, checkboxes, radio buttons
• Dropdowns, listboxes, tables, data grids, trees, markdown
• Menus, menubars, tabs, splitters, dialogs
• Progress bars, tooltips, date pickers
• Native open/save/folder dialogs (macOS + Linux; Windows under validation)

Rendering

• SDF-based drop shadows
• Linear and radial gradients
• Blur effects
• Custom fragment shaders (Metal + GLSL)
• Full SVG support (paths, transforms, groups, strokes)
• Mermaid diagram rendering

Animation

• Tweens with easing curves
• Physics-based springs
• Automatic layout transitions
• Hero morphs between views

Text (via vglyph/Pango)

• Subpixel positioning and hinting
• Rich text with mixed styles in a single widget
• Rotated and affine-transformed text
• Bidirectional text, ligatures, emoji
• Full Unicode and OpenType support
• IME support for CJK and other complex input methods

Architecture

• Thread-safe state updates
• 60 FPS with 1000+ widgets
• Pure V, no C bindings in user code

Quick Start

import gui

@[heap]
struct App {
pub mut:
	clicks int
}

fn main() {
	mut window := gui.window(
		state: &App{}
		on_init: fn (mut w gui.Window) { w.update_view(main_view) }
	)
	window.run()
}

fn main_view(window &gui.Window) gui.View {
	app := window.state[App]()
	return gui.column(
		h_align: .center
		v_align: .middle
		content: [
			gui.text(text: '${app.clicks} clicks'),
			gui.button(
				content: [gui.text(text: 'Click me')]
				on_click: fn (_ &gui.Layout, mut _ gui.Event, mut w gui.Window) {
					w.state[App]().clicks += 1
				}
			),
		]
	)
}

See GET_STARTED.md for a detailed walkthrough.

Installation

v install gui

Dependencies

Documentation

Generate API docs with:

v run _doc.vsh

Examples

The examples/ folder contains working apps for every feature:

v run examples/get_started.v    # Start here
v run examples/buttons.v        # Button variants
v run examples/animations.v     # Tweens and springs
v run examples/tiger.v          # SVG rendering demo
v run examples/markdown.v       # Markdown rendering
v run examples/dialogs.v        # Custom + native dialogs
v run examples/split_panel.v    # Splitter + nested splitter
v run examples/printing.v       # PDF export + platform print flow
v run examples/input_masks.v    # Input mask presets and custom tokens
v run examples/numeric_input.v  # Locale-aware numeric input + step controls
v run examples/form_validation.v # Form validation with sync+async validators
v run examples/text_transform.v # Rotated and affine text
v run examples/table_demo.v     # Table widget demo
v run examples/data_grid_demo.v # Data grid widget demo
v run examples/custom_shader.v  # Custom fragment shaders
v run examples/snake.v          # A complete game

Status

v-gui is in active development. Join the discussion on Discord.

Contributing

Contributions welcome:

• Report bugs and request features via GitHub issues
• Submit pull requests
• Improve documentation

License

MIT