Crate slt 

SLT — Super Light TUI

Immediate-mode terminal UI for Rust. Two dependencies. Zero unsafe.

SLT gives you an egui-style API for terminals: your closure runs each frame, you describe your UI, and SLT handles layout, diffing, and rendering.

Quick Start

fn main() -> std::io::Result<()> {
    slt::run(|ui| {
        ui.text("hello, world");
    })
}

Features

• Flexbox layout — row(), col(), gap(), grow()
• 30+ built-in widgets — input, textarea, table, list, tabs, button, checkbox, toggle, spinner, progress, toast, separator, help bar, scrollable, chart, bar chart, sparkline, histogram, canvas, grid, select, radio, multi-select, tree, virtual list, command palette, markdown
• Styling — bold, italic, dim, underline, 256 colors, RGB
• Mouse — click, hover, drag-to-scroll
• Focus — automatic Tab/Shift+Tab cycling
• Theming — dark/light presets or custom
• Animation — tween and spring primitives with 9 easing functions
• Inline mode — render below your prompt, no alternate screen
• Async — optional tokio integration via async feature
• Layout debugger — F12 to visualize container bounds

Feature Flags

Flag	Description
async	Enable run_async() with tokio channel-based message passing
serde	Enable Serialize/Deserialize for Style, Color, Theme, and layout types

Re-exports

pub use crate::test_utils::EventBuilder;

pub use crate::test_utils::TestBackend;

pub use anim::ease_in_cubic;

pub use anim::ease_in_out_cubic;

pub use anim::ease_in_out_quad;

pub use anim::ease_in_quad;

pub use anim::ease_linear;

pub use anim::ease_out_bounce;

pub use anim::ease_out_cubic;

pub use anim::ease_out_elastic;

pub use anim::ease_out_quad;

pub use anim::lerp;

pub use anim::Keyframes;

pub use anim::LoopMode;

pub use anim::Sequence;

pub use anim::Spring;

pub use anim::Stagger;

pub use anim::Tween;

pub use buffer::Buffer;

pub use cell::Cell;

pub use chart::Axis;

pub use chart::Candle;

pub use chart::ChartBuilder;

pub use chart::ChartConfig;

pub use chart::ChartRenderer;

pub use chart::Dataset;

pub use chart::DatasetEntry;

pub use chart::GraphType;

pub use chart::HistogramBuilder;

pub use chart::LegendPosition;

pub use chart::Marker;

pub use context::Bar;

pub use context::BarChartConfig;

pub use context::BarDirection;

pub use context::BarGroup;

pub use context::CanvasContext;

pub use context::ContainerBuilder;

pub use context::Context;

pub use context::Response;

pub use context::State;

pub use context::Widget;

pub use event::Event;

pub use event::KeyCode;

pub use event::KeyEventKind;

pub use event::KeyModifiers;

pub use event::MouseButton;

pub use event::MouseEvent;

pub use event::MouseKind;

pub use halfblock::HalfBlockImage;

pub use keymap::Binding;

pub use keymap::KeyMap;

pub use layout::Direction;

pub use palette::Palette;

pub use rect::Rect;

pub use style::Align;

pub use style::Border;

pub use style::BorderSides;

pub use style::Breakpoint;

pub use style::Color;

pub use style::ColorDepth;

pub use style::Constraints;

pub use style::ContainerStyle;

pub use style::Justify;

pub use style::Margin;

pub use style::Modifiers;

pub use style::Padding;

pub use style::Style;

pub use style::Theme;

pub use style::ThemeBuilder;

pub use style::WidgetColors;

pub use widgets::AlertLevel;

pub use widgets::ApprovalAction;

pub use widgets::ButtonVariant;

pub use widgets::CommandPaletteState;

pub use widgets::ContextItem;

pub use widgets::FileEntry;

pub use widgets::FilePickerState;

pub use widgets::FormField;

pub use widgets::FormState;

pub use widgets::ListState;

pub use widgets::MultiSelectState;

pub use widgets::PaletteCommand;

pub use widgets::RadioState;

pub use widgets::ScrollState;

pub use widgets::SelectState;

pub use widgets::SpinnerState;

pub use widgets::StreamingMarkdownState;

pub use widgets::StreamingTextState;

pub use widgets::TableState;

pub use widgets::TabsState;

pub use widgets::TextInputState;

pub use widgets::TextareaState;

pub use widgets::ToastLevel;

pub use widgets::ToastMessage;

pub use widgets::ToastState;

pub use widgets::ToolApprovalState;

pub use widgets::TreeNode;

pub use widgets::TreeState;

pub use widgets::Trend;

Modules

anim

Animation primitives: tweens, springs, keyframes, sequences, and staggers.

buffer

Double-buffer grid of Cells with clip-stack support.

cell

Single terminal cell — the smallest unit of the render buffer.

chart

Data visualization: line charts, scatter plots, bar charts, and histograms.

context

event

Terminal input events.

halfblock

Half-block image rendering for terminals with truecolor support.

keymap

layout

Flexbox layout engine: builds a tree from commands, computes positions, and renders to a Buffer.

palette

rect

Axis-aligned rectangle type used throughout SLT for layout regions, clipping bounds, and hit-test areas.

style

Visual styling primitives.

test_utils

Headless testing utilities.

widgets

Widget state types passed to Context widget methods.

Structs

AppState

Opaque per-session state that persists between frames.

RunConfig

Configuration for a TUI run loop.

Traits

Backend

Rendering backend for SLT.

Functions

frame

Process a single UI frame with a custom Backend.

run

Run the TUI loop with default configuration.

run_async

Run the TUI loop asynchronously with default configuration.

run_async_with

Run the TUI loop asynchronously with custom configuration.

run_inline

Run the TUI in inline mode with default configuration.

run_inline_with

Run the TUI in inline mode with custom configuration.

run_with

Run the TUI loop with custom configuration.