UI & Rendering

TRX's TUI is built on ratatui, a Rust library for building terminal UIs with a retained-mode, declarative rendering model.

Layout

draw_ui in src/ui/draw.rs computes the full layout on every frame:

┌─────────────────────────────────────────┐
│ Help header  (1 line)                   │
├─────────────────────────────────────────┤
│ Tab bar      (3 lines)                  │
├───────────────────────┬─────────────────┤
│                       │                 │
│  Package list         │  Details panel  │
│  + search input       │                 │
│  (Search tab only)    │                 │
│                       │                 │
├─────────────────────────────────────────┤
│ Status bar   (1 line)                   │
└─────────────────────────────────────────┘

The split between the list and details panel is responsive:

  • Terminal width ≥ 100 columns → 50 / 50 horizontal split
  • Terminal width < 100 columns → 60 / 40 split (still horizontal but tighter)

Input Modes

InputMode in src/ui/input.rs is a simple two-variant enum:

#![allow(unused)]
fn main() {
pub enum InputMode {
    Normal,
    Editing,
}
}
  • Normal — navigation, package operations, tab switching.
  • Editing — the search input bar is focused; characters are routed to App::enter_char / App::delete_char.

The cursor is hidden in Normal mode and shown at the current character position in Editing mode.

Spinner

While a background search or list-load is in progress, App::loading is true. The draw layer reads App::spinner_tick (incremented each frame) to index into a Braille spinner sequence:

#![allow(unused)]
fn main() {
const SPINNERS: [&str; 10] = ["⠋", "⠙", "⠹", "⠸", "⠼", "⠴", "⠦", "⠧", "⠇", "⠏"];
}

Help Overlay

Pressing ? sets App::show_help = true. draw_ui renders a centred popup over the main content using the centered_rect helper, which computes a rectangle as a percentage of the terminal area. The overlay is cleared with the ratatui Clear widget before drawing the help text on top.

Performance

  • Minimal redraws — the event loop uses a short poll timeout (not a busy-wait), so frames are only rendered when there is user input or a channel message.
  • No double-buffer diffing overhead — ratatui handles diffing internally; TRX simply calls terminal.draw(|frame| draw_ui(frame, app)) each iteration.
  • Pure functions in draw layer — draw_ui and its helpers take &mut App (for ListState selection) but do not mutate business logic, keeping rendering predictable and testable.