ratatui/README.md

<details>
<summary>Table of Contents</summary>

- [Ratatui](#ratatui)
  - [Quick Start](#quickstart)
  - [Other documentation](#other-documentation)
  - [Introduction](#introduction)
  - [Quickstart](#quickstart)
    - [Initialize and restore the terminal](#initialize-and-restore-the-terminal)
    - [Drawing the UI](#drawing-the-ui)
    - [Handling events](#handling-events)
  - [Layout](#layout)
  - [Text and styling](#text-and-styling)
  - [Status of this fork](#status-of-this-fork)
  - [Widgets](#widgets)
    - [Built in](#built-in)
    - [Third-party libraries, bootstrapping templates and widgets](#third-party-libraries-bootstrapping-templates-and-widgets)
  - [Apps](#apps)
  - [Alternatives](#alternatives)
  - [Acknowledgments](#acknowledgments)
  - [License](#license)

</details>

<!-- cargo-rdme start -->

![Demo](https://github.com/ratatui/ratatui/blob/87ae72dbc756067c97f6400d3e2a58eeb383776e/examples/demo2-destroy.gif?raw=true)

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[![Crate Badge]][Crate] [![Docs Badge]][API Docs] [![CI Badge]][CI Workflow] [![Deps.rs
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[![Forum Badge]][Forum]<br>

[Ratatui Website] · [API Docs] · [Examples] · [Changelog] · [Breaking Changes]<br>
[Contributing] · [Report a bug] · [Request a Feature] · [Create a Pull Request]

</div>

# Ratatui

[Ratatui][Ratatui Website] is a crate for cooking up terminal user interfaces in Rust. It is a
lightweight library that provides a set of widgets and utilities to build complex Rust TUIs.
Ratatui was forked from the [tui-rs] crate in 2023 in order to continue its development.

## Quickstart

Add `ratatui` and `crossterm` as dependencies to your cargo.toml:

```shell
cargo add ratatui crossterm
```

Then you can create a simple "Hello World" application:

```rust
use crossterm::event::{self, Event};
use ratatui::{text::Text, Frame};

fn main() {
    let mut terminal = ratatui::init();
    loop {
        terminal.draw(draw).expect("failed to draw frame");
        if matches!(event::read().expect("failed to read event"), Event::Key(_)) {
            break;
        }
    }
    ratatui::restore();
}

fn draw(frame: &mut Frame) {
    let text = Text::raw("Hello World!");
    frame.render_widget(text, frame.area());
}
```

The full code for this example which contains a little more detail is in the [Examples]
directory. For more guidance on different ways to structure your application see the
[Application Patterns] and [Hello World tutorial] sections in the [Ratatui Website] and the
various [Examples]. There are also several starter templates available in the [templates]
repository.

## Other documentation

- [Ratatui Website] - explains the library's concepts and provides step-by-step tutorials
- [Ratatui Forum][Forum] - a place to ask questions and discuss the library
- [API Docs] - the full API documentation for the library on docs.rs.
- [Examples] - a collection of examples that demonstrate how to use the library.
- [Contributing] - Please read this if you are interested in contributing to the project.
- [Changelog] - generated by [git-cliff] utilizing [Conventional Commits].
- [Breaking Changes] - a list of breaking changes in the library.

You can also watch the [FOSDEM 2024 talk] about Ratatui which gives a brief introduction to
terminal user interfaces and showcases the features of Ratatui, along with a hello world demo.

## Introduction

Ratatui is based on the principle of immediate rendering with intermediate buffers. This means
that for each frame, your app must render all widgets that are supposed to be part of the UI.
This is in contrast to the retained mode style of rendering where widgets are updated and then
automatically redrawn on the next frame. See the [Rendering] section of the [Ratatui Website]
for more info.

Ratatui uses [Crossterm] by default as it works on most platforms. See the [Installation]
section of the [Ratatui Website] for more details on how to use other backends ([Termion] /
[Termwiz]).

Every application built with `ratatui` needs to implement the following steps:

- Initialize the terminal
- A main loop that:
  - Draws the UI
  - Handles input events
- Restore the terminal state

### Initialize and restore the terminal

The [`Terminal`] type is the main entry point for any Ratatui application. It is generic over a
a choice of [`Backend`] implementations that each provide functionality to draw frames, clear
the screen, hide the cursor, etc. There are backend implementations for [Crossterm], [Termion]
and [Termwiz].

The simplest way to initialize the terminal is to use the [`init`] function which returns a
[`DefaultTerminal`] instance with the default options, enters the Alternate Screen and Raw mode
and sets up a panic hook that restores the terminal in case of panic. This instance can then be
used to draw frames and interact with the terminal state. (The [`DefaultTerminal`] instance is a
type alias for a terminal with the [`crossterm`] backend.) The [`restore`] function restores the
terminal to its original state.

```rust
fn main() -> std::io::Result<()> {
    let mut terminal = ratatui::init();
    let result = run(&mut terminal);
    ratatui::restore();
    result
}
```

See the [`backend` module] and the [Backends] section of the [Ratatui Website] for more info on
the alternate screen and raw mode.

### Drawing the UI

Drawing the UI is done by calling the [`Terminal::draw`] method on the terminal instance. This
method takes a closure that is called with a [`Frame`] instance. The [`Frame`] provides the size
of the area to draw to and allows the app to render any [`Widget`] using the provided
[`render_widget`] method. After this closure returns, a diff is performed and only the changes
are drawn to the terminal. See the [Widgets] section of the [Ratatui Website] for more info.

The closure passed to the [`Terminal::draw`] method should handle the rendering of a full frame.

```rust
use ratatui::{widgets::Paragraph, Frame};

fn run(terminal: &mut ratatui::DefaultTerminal) -> std::io::Result<()> {
    loop {
        terminal.draw(|frame| draw(frame))?;
        if handle_events()? {
            break Ok(());
        }
    }
}

fn draw(frame: &mut Frame) {
    let text = Paragraph::new("Hello World!");
    frame.render_widget(text, frame.area());
}
```

### Handling events

Ratatui does not include any input handling. Instead event handling can be implemented by
calling backend library methods directly. See the [Handling Events] section of the [Ratatui
Website] for more info. For example, if you are using [Crossterm], you can use the
[`crossterm::event`] module to handle events.

```rust
use crossterm::event::{self, Event, KeyCode, KeyEvent, KeyEventKind};

fn handle_events() -> std::io::Result<bool> {
    match event::read()? {
        Event::Key(key) if key.kind == KeyEventKind::Press => match key.code {
            KeyCode::Char('q') => return Ok(true),
            // handle other key events
            _ => {}
        },
        // handle other events
        _ => {}
    }
    Ok(false)
}
```

## Layout

The library comes with a basic yet useful layout management object called [`Layout`] which
allows you to split the available space into multiple areas and then render widgets in each
area. This lets you describe a responsive terminal UI by nesting layouts. See the [Layout]
section of the [Ratatui Website] for more info.

```rust
use ratatui::{
    layout::{Constraint, Layout},
    widgets::Block,
    Frame,
};

fn draw(frame: &mut Frame) {
    use Constraint::{Fill, Length, Min};

    let vertical = Layout::vertical([Length(1), Min(0), Length(1)]);
    let [title_area, main_area, status_area] = vertical.areas(frame.area());
    let horizontal = Layout::horizontal([Fill(1); 2]);
    let [left_area, right_area] = horizontal.areas(main_area);

    frame.render_widget(Block::bordered().title("Title Bar"), title_area);
    frame.render_widget(Block::bordered().title("Status Bar"), status_area);
    frame.render_widget(Block::bordered().title("Left"), left_area);
    frame.render_widget(Block::bordered().title("Right"), right_area);
}
```

Running this example produces the following output:

```text
Title Bar───────────────────────────────────
┌Left────────────────┐┌Right───────────────┐
│                    ││                    │
└────────────────────┘└────────────────────┘
Status Bar──────────────────────────────────
```

## Text and styling

The [`Text`], [`Line`] and [`Span`] types are the building blocks of the library and are used in
many places. [`Text`] is a list of [`Line`]s and a [`Line`] is a list of [`Span`]s. A [`Span`]
is a string with a specific style.

The [`style` module] provides types that represent the various styling options. The most
important one is [`Style`] which represents the foreground and background colors and the text
attributes of a [`Span`]. The [`style` module] also provides a [`Stylize`] trait that allows
short-hand syntax to apply a style to widgets and text. See the [Styling Text] section of the
[Ratatui Website] for more info.

```rust
use ratatui::{
    layout::{Constraint, Layout},
    style::{Color, Modifier, Style, Stylize},
    text::{Line, Span},
    widgets::{Block, Paragraph},
    Frame,
};

fn draw(frame: &mut Frame) {
    let areas = Layout::vertical([Constraint::Length(1); 4]).split(frame.area());

    let line = Line::from(vec![
        Span::raw("Hello "),
        Span::styled(
            "World",
            Style::new()
                .fg(Color::Green)
                .bg(Color::White)
                .add_modifier(Modifier::BOLD),
        ),
        "!".red().on_light_yellow().italic(),
    ]);
    frame.render_widget(line, areas[0]);

    // using the short-hand syntax and implicit conversions
    let paragraph = Paragraph::new("Hello World!".red().on_white().bold());
    frame.render_widget(paragraph, areas[1]);

    // style the whole widget instead of just the text
    let paragraph = Paragraph::new("Hello World!").style(Style::new().red().on_white());
    frame.render_widget(paragraph, areas[2]);

    // use the simpler short-hand syntax
    let paragraph = Paragraph::new("Hello World!").blue().on_yellow();
    frame.render_widget(paragraph, areas[3]);
}
```

[Ratatui Website]: https://ratatui.rs/
[Installation]: https://ratatui.rs/installation/
[Rendering]: https://ratatui.rs/concepts/rendering/
[Application Patterns]: https://ratatui.rs/concepts/application-patterns/
[Hello World tutorial]: https://ratatui.rs/tutorials/hello-world/
[Backends]: https://ratatui.rs/concepts/backends/
[Widgets]: https://ratatui.rs/how-to/widgets/
[Handling Events]: https://ratatui.rs/concepts/event-handling/
[Layout]: https://ratatui.rs/how-to/layout/
[Styling Text]: https://ratatui.rs/how-to/render/style-text/
[templates]: https://github.com/ratatui/templates/
[Examples]: https://github.com/ratatui/ratatui/tree/main/examples/README.md
[Report a bug]: https://github.com/ratatui/ratatui/issues/new?labels=bug&projects=&template=bug_report.md
[Request a Feature]: https://github.com/ratatui/ratatui/issues/new?labels=enhancement&projects=&template=feature_request.md
[Create a Pull Request]: https://github.com/ratatui/ratatui/compare
[git-cliff]: https://git-cliff.org
[Conventional Commits]: https://www.conventionalcommits.org
[API Docs]: https://docs.rs/ratatui
[Changelog]: https://github.com/ratatui/ratatui/blob/main/CHANGELOG.md
[Contributing]: https://github.com/ratatui/ratatui/blob/main/CONTRIBUTING.md
[Breaking Changes]: https://github.com/ratatui/ratatui/blob/main/BREAKING-CHANGES.md
[FOSDEM 2024 talk]: https://www.youtube.com/watch?v=NU0q6NOLJ20
[`Frame`]: terminal::Frame
[`render_widget`]: terminal::Frame::render_widget
[`Widget`]: widgets::Widget
[`Layout`]: layout::Layout
[`Text`]: text::Text
[`Line`]: text::Line
[`Span`]: text::Span
[`Style`]: style::Style
[`style` module]: style
[`Stylize`]: style::Stylize
[`Backend`]: backend::Backend
[`backend` module]: backend
[`crossterm::event`]: https://docs.rs/crossterm/latest/crossterm/event/index.html
[Crate]: https://crates.io/crates/ratatui
[Crossterm]: https://crates.io/crates/crossterm
[Termion]: https://crates.io/crates/termion
[Termwiz]: https://crates.io/crates/termwiz
[tui-rs]: https://crates.io/crates/tui
[GitHub Sponsors]: https://github.com/sponsors/ratatui
[Crate Badge]: https://img.shields.io/crates/v/ratatui?logo=rust&style=flat-square&logoColor=E05D44&color=E05D44
[License Badge]: https://img.shields.io/crates/l/ratatui?style=flat-square&color=1370D3
[CI Badge]: https://img.shields.io/github/actions/workflow/status/ratatui/ratatui/ci.yml?style=flat-square&logo=github
[CI Workflow]: https://github.com/ratatui/ratatui/actions/workflows/ci.yml
[Codecov Badge]: https://img.shields.io/codecov/c/github/ratatui/ratatui?logo=codecov&style=flat-square&token=BAQ8SOKEST&color=C43AC3&logoColor=C43AC3
[Codecov]: https://app.codecov.io/gh/ratatui/ratatui
[Deps.rs Badge]: https://deps.rs/repo/github/ratatui/ratatui/status.svg?style=flat-square
[Deps.rs]: https://deps.rs/repo/github/ratatui/ratatui
[Discord Badge]: https://img.shields.io/discord/1070692720437383208?label=discord&logo=discord&style=flat-square&color=1370D3&logoColor=1370D3
[Discord Server]: https://discord.gg/pMCEU9hNEj
[Docs Badge]: https://img.shields.io/docsrs/ratatui?logo=rust&style=flat-square&logoColor=E05D44
[Matrix Badge]: https://img.shields.io/matrix/ratatui-general%3Amatrix.org?style=flat-square&logo=matrix&label=Matrix&color=C43AC3
[Matrix]: https://matrix.to/#/#ratatui:matrix.org
[Forum Badge]: https://img.shields.io/discourse/likes?server=https%3A%2F%2Fforum.ratatui.rs&style=flat-square&logo=discourse&label=forum&color=C43AC3
[Forum]: https://forum.ratatui.rs
[Sponsors Badge]: https://img.shields.io/github/sponsors/ratatui?logo=github&style=flat-square&color=1370D3

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## Contributing

In order to organize ourselves, we currently use a [Discord server](https://discord.gg/pMCEU9hNEj),
feel free to join and come chat! There is also a [Matrix](https://matrix.org/) bridge available at
[#ratatui:matrix.org](https://matrix.to/#/#ratatui:matrix.org).

We have also recently launched the [Ratatui Forum][Forum], For bugs and features, we rely on GitHub.
Please [Report a bug], [Request a Feature] or [Create a Pull Request].

Please make sure you read the [contributing](./CONTRIBUTING.md) guidelines, especially if you are
interested in working on a PR or issue opened in the previous repository.

## Built with Ratatui

Ratatui has a number of built-in [widgets](https://docs.rs/ratatui/latest/ratatui/widgets/), as well
as many contributed by external contributors. Check out the [Showcase](https://ratatui.rs/showcase/)
section of the website, or the [awesome-ratatui](https://github.com/ratatui/awesome-ratatui) repo
for a curated list of awesome apps/libraries built with `ratatui`!

## Alternatives

You might want to checkout [Cursive](https://github.com/gyscos/Cursive) or 
[iocraft](https://github.com/ccbrown/iocraft/) for an alternative solutions
to build text user interfaces in Rust.

## Acknowledgments

None of this could be possible without [**Florian Dehau**](https://github.com/fdehau) who originally
created [tui-rs] which inspired many Rust TUIs.

Special thanks to [**Pavel Fomchenkov**](https://github.com/nawok) for his work in designing **an
awesome logo** for the ratatui project and ratatui organization.

## License

[MIT](./LICENSE)