Pi Tui

Pi TUI — Terminal UI framework with differential rendering + synchronized output for flicker-free interactive CLIs.

Component-based architecture (TUI/Container/Box/Text/TruncatedText/Input/Editor/Markdown/Loader/CancellableLoader/SelectList/SettingsList/Spacer/Image), overlay system, IME support, autocomplete, Kitty keyboard protocol. Differential rendering TUI framework. Install: npm install @earendil-works/pi-tui

Use Cases

Use when building terminal UIs, interactive CLI apps, TUI editors, terminal select lists/settings panels, terminal Markdown rendering, or inline terminal images.

Core Concepts

Component Interface — All components implement render(width): string[] (each line ≤ width), handleInput?(data), invalidate?(). Each line auto-appends SGR+OSC reset; styles do not carry across lines.

Focusable Interface — Components needing IME implement a focused: boolean property and insert CURSOR_MARKER before the cursor in render. Containers with Input/Editor children must propagate focus state (otherwise IME candidate window mispositions). Hardware cursor hidden by default; enable with PI_HARDWARE_CURSOR=1.

Differential Rendering — Three strategies: first render outputs all lines, width change clears and redraws, incremental only updates changed lines. CSI 2026 synchronized output prevents flicker.

Quick Start

import { TUI, Text, Editor, ProcessTerminal, matchesKey } from "@earendil-works/pi-tui";

const tui = new TUI(new ProcessTerminal());
tui.addChild(new Text("Welcome!"));
const editor = new Editor(tui, theme);
editor.onSubmit = (text) => tui.addChild(new Text(`> ${text}`));
tui.addChild(editor);
tui.setFocus(editor);
tui.addInputListener((data) => { if (matchesKey(data, 'ctrl+c')) { tui.stop(); process.exit(0); } });
tui.start();

// TUI API: addChild/removeChild/start/stop/requestRender/setFocus/onDebug

Progressive References

Load on demand, only when needed:

• Overlays/dialogs/menus → references/overlays.md
• Component API reference → references/components.md
• Autocomplete/key detection → references/autocomplete.md

Gotchas

1. render(width) line width: each line ≤ width, otherwise TUI throws
2. Styles don't span lines: auto-reset at line end, reapply styles per line for multi-line styled text
3. Container IME propagation: containers with Input/Editor must implement Focusable and propagate focus
4. Ctrl+C: raw mode doesn't send SIGINT, must handle via matchesKey(data, 'ctrl+c')
5. Overlay focus: unfocus({ target: component }) releases to specific component, unfocus({ target: null }) clears focus