Crate flywheel 

Flywheel

A zero-flicker terminal compositor for Agentic CLIs.

Flywheel is a purpose-built TUI engine designed for high-frequency token streaming (100+ tokens/s) without flickering, blocking, or latency.

Core Concepts

• Double-buffered rendering: Current and Next buffers with minimal diff
• Dirty rectangles: Only re-render changed regions
• Actor model: Isolated threads for input, rendering, and agent logic
• Optimistic append: Fast path for streaming text that bypasses diffing

Example

use flywheel::{Buffer, Cell, Rect};

// Create a buffer for a 80x24 terminal
let mut buffer = Buffer::new(80, 24);

// Write a cell
buffer.set(0, 0, Cell::new('H'));

Re-exports

pub use buffer::Buffer;

pub use buffer::Cell;

pub use buffer::CellFlags;

pub use buffer::Modifiers;

pub use buffer::Rgb;

pub use buffer::RopeBuffer;

pub use buffer::ChunkedLine;

pub use buffer::RopeMemoryStats;

pub use layout::Layout;

pub use layout::Rect;

pub use layout::Region;

pub use layout::RegionId;

pub use actor::Engine;

pub use actor::EngineConfig;

pub use actor::InputEvent;

pub use actor::KeyCode;

pub use actor::KeyModifiers;

pub use actor::RenderCommand;

pub use actor::AgentEvent;

pub use actor::TickerActor;

pub use actor::Tick;

pub use widget::Widget;

pub use widget::StreamWidget;

pub use widget::StreamConfig;

pub use widget::AppendResult;

pub use widget::ScrollBuffer;

pub use widget::TextInput;

pub use widget::TextInputConfig;

pub use widget::StatusBar;

pub use widget::StatusBarConfig;

pub use widget::ProgressBar;

pub use widget::ProgressBarConfig;

pub use widget::ProgressStyle;

pub use widget::Terminal;

Modules

actor

Actor Model: Message-passing concurrency for the TUI engine.

buffer

Buffer module: Core data structures for the double-buffer rendering system.

ffi

C Foreign Function Interface (FFI) for Flywheel.

layout

Layout module: Pre-computed static regions for efficient rendering.

terminal

Terminal module: Backend abstraction and output buffering.

widget

Widget System: Composable UI components for terminal applications.