Tui Design

TUI Design System

Design around the user's repeated action, the data they must keep in view, and the terminal capabilities actually available. Keep input responsive under slow I/O and make selection, focus, and operation state explicit.

Primary documentation checked: 2026-09-04. Framework APIs change; use the project's versions. Follow the project's visual identity (SilkCircuit Neon for Bliss's personal tools) rather than treating an example palette as a universal theme.

Choose the Layout from the Work

Read app-patterns.md for examples and tradeoffs. Read visual-catalog.md only when selecting glyphs, borders, charts, or indicators.

Responsive Behavior

Use constraints and content priorities. Keep the selected item visible while collapsing secondary panels; preserve state when they reappear. Recompute layout on resize without treating a zero-sized transient area as an error. Clamp scrolling after filtering, deletion, or a smaller viewport.

Test narrow, ordinary, and wide layouts, including rapid resizing. The minimum usable size follows the task; 80x24 is a useful test case, not permission to disable a picker that would work in 40 columns. A size message should retain quit and recovery input.

Input, Focus, and Editing

Maintain one owner for input parsing. With Crossterm, do not mix EventStream with read/poll, or run competing readers. Handle key press, repeat, and release deliberately; one physical press must not submit twice.

Enhanced keyboard protocols can distinguish keys that legacy terminals encode identically. Negotiate support and retain usable fallback bindings. Never assume Ctrl+I differs from Tab or Ctrl+M from Enter everywhere. Treat bracketed paste as a text event; pasted newlines must not accidentally submit destructive commands.

Raw mode can disable the terminal's normal signal handling. Implement Ctrl+C and suspend/resume deliberately through the framework; do not assume the OS will handle them unchanged. Restore terminal state before handing control to an editor, pager, shell, or suspended process, then reacquire it and redraw.

Show a short footer for currently available actions and a contextual help view. Keep essential instructions visible while a task is running. Durable errors need a retrievable location; a disappearing toast cannot be the only record.

State and Async Work

Separate input events, state transitions, effects, and rendering. Render a snapshot of state without starting network calls or mutating the domain model from a drawing function.

digraph tui_state {
    rankdir=LR;
    event -> update;
    update -> state;
    update -> effect;
    effect -> event [label="result + request identity"];
    state -> render;
}

Batch state updates and render changed frames. Coalesce replaceable visual snapshots, not audit events or mutations. Diagnose queue growth, indexing, and allocation costs before dropping data or capping concurrency.

Terminal Capability Policy

Explicit application settings take precedence. In automatic mode, respect a non-empty NO_COLOR before color detection. A color override can opt back in deliberately; disabling color need not disable bold, underline, layout, or every terminal feature.