Crate rnk 

rnk - React-like Terminal UI for Rust

A terminal UI framework inspired by Ink and Bubbletea.

Features

• Declarative UI with flexbox layout
• Reactive state management with hooks
• Keyboard and mouse input handling
• ANSI color and style support
• Inline mode (default): Output persists in terminal history
• Fullscreen mode: Uses alternate screen buffer
• Cross-thread render requests for async/multi-threaded apps
• Runtime mode switching between inline and fullscreen
• Println for persistent messages above the UI

Quick Start

use rnk::prelude::*;

fn main() -> std::io::Result<()> {
    render(app).run()
}

fn app() -> Element {
    Box::new()
        .padding(1)
        .child(Text::new("Hello, rnk!").bold().into_element())
        .into_element()
}

Render Modes

Inline Mode (Default)

Output appears at the current cursor position and persists in terminal history. This is the default mode, matching Ink and Bubbletea’s behavior.

render(app).run()?;           // Inline mode (default)
render(app).inline().run()?;  // Explicit inline mode

Fullscreen Mode

Uses the alternate screen buffer. Content is cleared when the app exits.

render(app).fullscreen().run()?;

Runtime Mode Switching

Switch between modes at runtime (like Bubbletea):

let app = use_app();

use_input(move |key| {
    if key == Key::Char(' ') {
        if app.is_alt_screen() {
            app.exit_alt_screen();  // Switch to inline
        } else {
            app.enter_alt_screen(); // Switch to fullscreen
        }
    }
});

Println for Persistent Messages

In inline mode, use println() to output messages above the UI:

use rnk::println;

// In an input handler
rnk::println("Task completed!");
rnk::println(format!("Downloaded {} files", count));

// Or via AppContext
let app = use_app();
app.println("Another message");

Cross-Thread Rendering

When updating state from a background thread, use request_render() to notify the UI to refresh:

use std::thread;
use std::sync::{Arc, RwLock};
use rnk::request_render;

let state = Arc::new(RwLock::new(0));
let state_clone = Arc::clone(&state);

thread::spawn(move || {
    *state_clone.write().unwrap() += 1;
    request_render(); // Notify rnk to re-render
});

Re-exports

pub use crate::components::Box;

pub use crate::components::Text;

pub use crate::core::Color;

pub use crate::core::Element;

pub use crate::core::ElementId;

pub use crate::core::Style;

pub use crate::renderer::AppBuilder;

pub use crate::renderer::AppOptions;

pub use crate::renderer::IntoPrintable;

pub use crate::renderer::ModeSwitch;

pub use crate::renderer::Printable;

pub use crate::renderer::RenderHandle;

pub use crate::renderer::enter_alt_screen;

pub use crate::renderer::exit_alt_screen;

pub use crate::renderer::is_alt_screen;

pub use crate::renderer::println;

pub use crate::renderer::println_trimmed;

pub use crate::renderer::render;

pub use crate::renderer::render_fullscreen;

pub use crate::renderer::render_handle;

pub use crate::renderer::render_inline;

pub use crate::renderer::render_to_string;

pub use crate::renderer::render_to_string;

pub use crate::renderer::render_to_string_auto;

pub use crate::renderer::render_to_string_no_trim;

pub use crate::renderer::request_render;

Modules

animation

Animation system

cmd

Command System for managing side effects

components

UI Components

core

Core types and abstractions

hooks

Hooks system for reactive state management

layout

Layout system using Taffy

macros

Declarative UI macros for rnk

prelude

Prelude module - commonly used imports

reconciler

Reconciliation system for efficient UI updates

renderer

Rendering system

runtime

Runtime utilities for terminal state management

testing

Testing utilities for verifying UI components Testing infrastructure for Tink

Macros

box_element

Create a Box element with children

col

Create a vertical column layout (flex-direction: column)

golden_test

Macro for creating golden tests

list

Create a list of elements from an iterator

list_indexed

Create a list of elements with index from an iterator

row

Create a horizontal row layout (flex-direction: row)

spacer

Create a Spacer element

styled_text

Create a styled Text element

text

Create a Text element

when

Conditional rendering helper