GUI

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

Note: I don't own a Windows computer and cannot help with Windows issues. Windows may be supported in the future, it is not supported now. Some users have successfully made this framework run on Windows. If you choose to go down that path, I suggest joining the V community on Discord where people way more smarter than me can help you. - mrw

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)

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

Package	Purpose	Source
vglyph	Text rendering	Auto-installed with v-gui
gg	2D graphics	V standard library
sokol.sapp	Windowing and events	V standard library

Documentation

Document	Description
GET_STARTED.md	Tutorial: first app to working knowledge
ARCHITECTURE.md	How v-gui works under the hood
LAYOUT_ALGORITHM.md	Sizing, alignment, and positioning
ANIMATIONS.md	Tweens, springs, and transitions
SVG.md	Vector graphics and icon rendering
MARKDOWN.md	Markdown rendering
TABLES.md	Table widget and data display
DATA_GRID.md	Data grid widget and API
FORMS.md	Form runtime, validation model, and field adapters
GRADIENTS.md	Linear and radial gradients
SHADERS.md	Custom fragment shaders
PRINTING.md	PDF export and native print dialog
SPLITTER.md	Splitter component (drag, collapse, keyboard)

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/theme_designer.v # Build custom themes
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 + native print
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