Ratatui Tui

Ratatui TUI Development

Quick Start

1. Copy template to project:

   cp -r ~/.agents/skills/ratatui-tui/assets/templates/<template>/* .
   

   Or generate from the official templates repo:

   cargo install --locked cargo-generate
   cargo generate ratatui/templates
   

2. Run:

   cargo run
   

Version Notes (0.30.x)

Current stable: 0.30.1 (2026-06-05, MSRV 1.88, edition 2024).

• Modular workspace: apps keep depending on ratatui; widget libraries should depend on ratatui-core for API stability and fewer dependencies.
• ratatui::run(|terminal| ...): initializes the terminal, installs a panic hook that restores it, runs the closure, and restores on exit.
• Block::shadow(...) (new in 0.30.1): drop shadows for blocks/popups.
• Breaking since 0.29: block::Title removed, layout::Alignment renamed to HorizontalAlignment, Flex::SpaceAround now matches flexbox semantics (use Flex::SpaceEvenly for the old behavior), Marker is non-exhaustive.
• Performance: disabling default-features also disables layout-cache; re-enable it explicitly or layout performance drops sharply.

Template Selection

Decision tree:

• Need async/network? → async-app
• Multiple screens/components? → component-app
• Just a simple tool? → simple-app
• Learning ratatui? → hello-world

Project Setup

Minimal Cargo.toml

[package]
name = "my-tui"
version = "0.1.0"
edition = "2024"

[dependencies]
ratatui = "0.30"
crossterm = "0.29"
color-eyre = "0.6"

Full Dependencies (component-app)

[dependencies]
ratatui = "0.30"
crossterm = { version = "0.29", features = ["event-stream"] }
color-eyre = "0.6"
tokio = { version = "1", features = ["full"] }
futures = "0.3"
clap = { version = "4", features = ["derive"] }
tracing = "0.1"
tracing-subscriber = { version = "0.3", features = ["env-filter"] }
serde = { version = "1", features = ["derive"] }
config = "0.15"
dirs = "6"

# Optional: image support
ratatui-image = { version = "5", features = ["chafa-static"] }

# Optional: shimmer text animation
tui-shimmer = "0.1"

Release Profile

[profile.release]
lto = true
codegen-units = 1
panic = "abort"
strip = true

Core Loop: TEA (The Elm Architecture)

Model → Message → Update → View
  ↑                         |
  └─────────────────────────┘

struct App {
    counter: i32,
    should_quit: bool,
}

enum Message {
    Increment,
    Decrement,
    Quit,
}

impl App {
    fn update(&mut self, msg: Message) {
        match msg {
            Message::Increment => self.counter += 1,
            Message::Decrement => self.counter -= 1,
            Message::Quit => self.should_quit = true,
        }
    }

    fn view(&self, frame: &mut Frame) {
        let text = format!("Counter: {}", self.counter);
        frame.render_widget(Paragraph::new(text), frame.area());
    }
}

Styling Rules

Use Stylize trait helpers:

use ratatui::style::Stylize;

// Good
"text".bold()
"text".dim()
"text".cyan()
"text".on_dark_gray()
"text".bold().cyan()

// Avoid
Style::default().fg(Color::White)  // hardcoded white
Style::default().fg(Color::Black)  // hardcoded black
Style::new().add_modifier(Modifier::BOLD)  // verbose

Color palette:

• Primary: .cyan(), .green()
• Error: .red()
• Warning: .yellow() (sparingly)
• Muted: .dim(), .dark_gray()
• Accent: .magenta()

Text wrapping:

use textwrap::wrap;
use ratatui::text::Line;

let wrapped: Vec<Line> = wrap(&long_text, width as usize)
    .into_iter()
    .map(|cow| Line::from(cow.into_owned()))
    .collect();

See: references/style-guide.md

Widget Patterns

StatefulWidget

struct MyList {
    items: Vec<String>,
}

struct MyListState {
    selected: usize,
}

impl StatefulWidget for MyList {
    type State = MyListState;

    fn render(self, area: Rect, buf: &mut Buffer, state: &mut Self::State) {
        // render with state.selected
    }
}

// Usage
frame.render_stateful_widget(my_list, area, &mut state);

Layout

let [header, main, footer] = Layout::vertical([
    Constraint::Length(1),
    Constraint::Fill(1),
    Constraint::Length(1),
]).areas(frame.area());

let [left, right] = Layout::horizontal([
    Constraint::Percentage(30),
    Constraint::Fill(1),
]).areas(main);

Built-in State Types

• ListState - for List widget
• TableState - for Table widget
• ScrollbarState - for Scrollbar

See: references/architecture-patterns.md

Async Event Handling

use crossterm::event::{EventStream, Event, KeyCode};
use futures::StreamExt;
use tokio::select;

async fn run(mut app: App) -> Result<()> {
    let mut events = EventStream::new();

    loop {
        // Render
        terminal.draw(|f| app.view(f))?;

        // Handle events
        select! {
            Some(Ok(event)) = events.next() => {
                if let Event::Key(key) = event {
                    match key.code {
                        KeyCode::Char('q') => break,
                        KeyCode::Up => app.update(Message::Up),
                        KeyCode::Down => app.update(Message::Down),
                        _ => {}
                    }
                }
            }
            // Add other channels here (background tasks, timers)
        }

        if app.should_quit {
            break;
        }
    }
    Ok(())
}

See: references/async-patterns.md

Image Integration

use ratatui_image::{picker::Picker, StatefulImage, Resize};
use std::thread;

// Query terminal protocol support once at startup; keep it on the app
let picker = Picker::from_query_stdio()?;

// Load and resize in a background thread (`area` is the target Rect
// from your layout; clone the picker so the original stays reusable)
let (tx, rx) = std::sync::mpsc::channel();
let mut worker = picker.clone();
thread::spawn(move || {
    let dyn_img = image::open("photo.png").unwrap();
    let protocol = worker.new_protocol(dyn_img, area.into(), Resize::Fit(None));
    tx.send(protocol).unwrap();
});

// In render, use StatefulImage for efficient redraw
if let Ok(protocol) = rx.try_recv() {
    image_state = Some(protocol);
}
if let Some(ref mut img) = image_state {
    frame.render_stateful_widget(StatefulImage::default(), area, img);
}

Key points:

• Use chafa-static feature for portable binaries
• Query protocol once, not per-frame
• Offload resize/encode to background thread
• Use StatefulImage to avoid re-encoding on redraws

See: references/image-integration.md

Shimmer / Loading Animation

tui-shimmer sweeps a highlight across text — the "Loading…"/"Thinking…" effect used by coding-agent TUIs.

use ratatui::style::Style;
use ratatui::text::Line;
use tui_shimmer::{shimmer_spans_with_style, shimmer_spans_with_style_at_phase};

// Time-driven (call every frame; re-render on a tick to animate)
let spans = shimmer_spans_with_style("Loading...", Style::new().cyan());
frame.render_widget(Line::from(spans), area);

// Deterministic: drive phase (0.0..1.0) from app state — testable, pausable
let phase = (self.start.elapsed().as_secs_f32() / 2.0) % 1.0;
let spans = shimmer_spans_with_style_at_phase("Working...", Style::new().cyan(), phase);

Key points:

• Animation needs redraws: add a tick event (~80-120ms) to the event loop (select! with tokio::time::interval, or event::poll timeout)
• Prefer the _at_phase variant with phase stored in the Model — keeps rendering pure and animation testable
• True color with automatic fallback for limited terminals
• API is experimental until 1.0 — pin and review minor bumps

Error Handling

ratatui::run() / ratatui::init() install a panic hook that restores the terminal before panicking — do not write one by hand. Install color-eyre first so the terminal is restored before its report prints:

use color_eyre::eyre::Result;

fn main() -> Result<()> {
    color_eyre::install()?;        // eyre hooks before terminal init
    // App::run is the app's own main loop (see templates), not a ratatui API
    let result = ratatui::run(|terminal| App::default().run(terminal));
    Ok(result?)
}

Only write a manual panic hook when constructing Terminal/Backend by hand instead of via ratatui::init().

Error propagation:

// Use ? for recoverable errors
let file = std::fs::read_to_string(path)?;

// Use color_eyre context
let config = load_config()
    .wrap_err("Failed to load configuration")?;

Release Build

cargo build --release

Binary at target/release/<name>.

Size optimization — replaces the Release Profile block above when binary size matters more than speed:

[profile.release]
lto = true
codegen-units = 1
panic = "abort"
strip = true
opt-level = "z"  # size over speed

Templates Overview

hello-world (~25 lines)

Minimal ratatui demo using ratatui::run().

simple-app (~80 lines)

Synchronous event loop, App struct, basic render.

async-app (~120 lines)

Tokio runtime, EventStream, select! pattern.

component-app (~300 lines)

Full modular structure:

• main.rs - entry point
• app.rs - App state, update logic
• event.rs - event handling
• ui.rs - rendering
• action.rs - Action enum
• tui.rs - terminal setup
• config.rs - configuration with dirs
• logging.rs - tracing setup

Common Patterns

Centered Popup

fn centered_rect(percent_x: u16, percent_y: u16, area: Rect) -> Rect {
    let [_, center, _] = Layout::vertical([
        Constraint::Percentage((100 - percent_y) / 2),
        Constraint::Percentage(percent_y),
        Constraint::Percentage((100 - percent_y) / 2),
    ]).areas(area);

    let [_, center, _] = Layout::horizontal([
        Constraint::Percentage((100 - percent_x) / 2),
        Constraint::Percentage(percent_x),
        Constraint::Percentage((100 - percent_x) / 2),
    ]).areas(center);

    center
}

With a drop shadow (0.30.1+):

use ratatui::layout::Offset;
use ratatui::widgets::{Block, Shadow};

let popup = Block::bordered()
    .title("Confirm")
    .shadow(Shadow::dark_shade().offset(Offset::new(2, 1)));

Key Bindings Display

let help = Line::from(vec![
    " q ".bold().cyan(),
    "quit ".dim(),
    " ↑↓ ".bold().cyan(),
    "navigate ".dim(),
    " Enter ".bold().cyan(),
    "select ".dim(),
]);

Status Bar

let status = Line::from(vec![
    " MODE ".bold().on_cyan(),
    format!(" {} items ", count).dim().into(),
]);

Multi-Agent TUI Review Workflow

workflows/tui-review.js is a dynamic-workflow template for Claude Code's Workflow tool. It fans out one reviewer per TUI dimension — TEA architecture, terminal safety, styling, event handling, render performance — then adversarially verifies each finding before reporting, so only confirmed issues survive. In agents without the Workflow tool (Codex, Gemini), skip the script and apply those five dimensions as a manual review checklist instead.

Treat it as a template, not a script to run verbatim: adjust the target path, dimensions, and severity threshold to the codebase. Run it after substantial TUI changes or before a release:

Workflow({
  scriptPath: "~/.agents/skills/ratatui-tui/workflows/tui-review.js",
  args: { path: "src/" },
})

Or ask: "run the TUI review workflow from the ratatui-tui skill on src/".

Checklist

Before shipping:

• cargo fmt
• cargo clippy --all-features clean
• No unwrap() outside tests
• Terminal restored on all exit paths (ratatui::run() or init/restore)
• cargo build --release succeeds
• Test on target terminal(s)