Niri Bar

Pixel-perfect, CSS-themed, configuration-driven bar for the Niri Wayland compositor.

Requirements

• Linux + Wayland only (Niri WM). No X11/macOS/Windows.
• GTK4 + gtk4-layer-shell.
• Rust toolchain (stable).
• Optional (for wallpaper switching): swww (recommended) or swaybg installed and running.
• Optional (for battery/power): powerprofilesctl for power profile switching.

Build and Run

cargo build --release
./target/release/niri-bar

Configure (YAML is the source of truth)

Edit niri-bar.yaml. Key sections:

• application.theme: one of wombat, solarized, dracula (default: wombat).
• application.modules: global module defaults (use YAML anchors/aliases).
• application.layouts: reusable layout profiles (columns → modules + overflow policy).
• application.monitors: list of regex-matched monitors with enabled, layout, modules overrides.

Example (excerpt):

application:
  theme: wombat
  modules:
    clock: &clock_default { format: "%a %b %d, %Y @ %H:%M:%S", tooltip: true }
  layouts:
    three_column: &layout_three
      columns:
        left:   { modules: ["workspaces"], overflow: hide }
        center: { modules: ["window_title"], overflow: hide }
        right:  { modules: ["clock", "battery", "system"], overflow: kebab }
  monitors:
    - match: ".*"
      enabled: true
      layout: { <<: *layout_three }

Theming (CSS)

• Themes live in themes/ (wombat.css, solarized.css, dracula.css).
• Every monitor/column/module gets stable CSS classes/ids for granular styling.
• Hot-reload: editing niri-bar.yaml or any CSS in themes/ updates the bar immediately.

Columns

• GTK homogeneous layout ensures equal spacing and perfect centering (odd: exact center, even: symmetric).
• Column names are for CSS only; renderer uses order/count.
• Per-column overflow: hide (crop) or kebab (dropdown popover for overflowed items).

Modules (dynamic)

Modules are loaded via a registry by name (e.g., clock → bar.module.clock).

• clock: single format string, updates every 1s independently.
• window_title: shows focused window title via Niri IPC state.
• workspaces: buttons per workspace; click to focus; wheel to next/prev; scroll_wraparound supported; optional show_wallpaper for button thumbnails.
• battery: shows charge % + icon; optional power profile dropdown (requires powerprofilesctl); pulse animation.
• tray: system tray icons (StatusNotifierHost) with right-click menus; supports swww/swaybg providers.

Wallpaper Switching

Configured in application.wallpapers:

• default: fallback wallpaper path.
• by_workspace: map workspace name/index to specific paths (e.g., "1", "dev").
• special_cmd: custom command with ${current_workspace_image} substitution.
• Automatically switches wallpaper on workspace focus using: special_cmd → swww → swaybg → none.

Logging

• Default file: ~/.local/share/niri-bar/niri-bar.log.

Testing & CI

• All tests live under tests/; none inline in src/* unless critical.
• Validate the real niri-bar.yaml against src/niri-bar-yaml.schema.json.

cargo test -- --test-threads=1
# Style & lint
cargo fmt -- --check
cargo clippy -- -D warnings

Niri IPC

• One persistent read socket (event stream), one short-lived write socket per request (no batching).
• State cached in a central bus consumed by UI modules on the GTK thread.

Troubleshooting

• Ensure Niri is running (Wayland) and $NIRI_SOCKET is set by the compositor.
• If nothing appears: check logs, validate YAML (cargo test -- tests/config_tests.rs).

Documentation

See the wiki/ folder for detailed architecture, configuration, theming, IPC, hot-reload, testing, and logging docs.