Jag

GPU-accelerated 2D rendering and UI toolkit for Rust.

Build interactive UIs with composable elements, GPU-powered rendering via wgpu, and automatic flex/grid layout via Taffy.

Crates

Crate	Description
jag	Meta-crate re-exporting jag-draw, jag-ui, and jag-surface
jag-draw	Low-level GPU 2D renderer (display list, painter, pass manager)
jag-ui	UI elements, widgets, events, focus, and Taffy-based layout
jag-surface	Canvas-style drawing API on top of jag-draw

Quick Start

[dependencies]
jag = "0.1"
winit = "0.30"
pollster = "0.3"

use jag::draw::{JagTextProvider, SubpixelOrientation, Rect};
use jag::surface::JagSurface;
use jag::ui::elements::{Button, Checkbox, Text, Element};
use jag::ui::Theme;

// Create elements
let theme = Theme::default();
let mut btn = Button::with_theme("Click me", &theme);
btn.rect = Rect { x: 40.0, y: 100.0, w: 160.0, h: 40.0 };

// Render to a canvas
btn.render(&mut canvas, 10);

Features

• GPU-accelerated rendering — wgpu backend with display list batching
• 19 UI elements — Button, InputBox, TextArea, Checkbox, Radio, Select, ToggleSwitch, Slider, DatePicker, Link, Container, Card, Modal, Alert, Badge, Table, Image, Text
• Widgets — TextInput, TabBar, PopupMenu with built-in state management
• Event handling — Mouse, keyboard, and scroll events with hit testing
• Focus management — Tab navigation with configurable tab indices
• Theming — Dark/Light modes with customizable colors
• Layout — Taffy-based flex and grid layout
• Text rendering — System font loading, shaping (harfrust), rasterization (swash), subpixel rendering
• Canvas API — Higher-level drawing with rounded rects, images, gradients, SVG, shadows

Running the Demo

git clone https://github.com/jag-rs/jag.git
cd jag
cargo run -p jag-demo

Architecture

jag (meta-crate)
├── jag-draw     — GPU renderer (wgpu display list pipeline)
│   ├── jag-shaders  — WGSL shader modules
│   └── jag-text     — Text layout and shaping engine
├── jag-surface  — Canvas API (fill_rect, draw_text, images, etc.)
└── jag-ui       — UI elements, widgets, events, layout

License

MIT License. See LICENSE-MIT for details.

Contributing

Contributions are welcome! Please open an issue or pull request on GitHub.