A modern, skinnable desktop app for rockboxd, built with Slint. Inspired by jetAudio (VFD readout), Mixxx (LED level meters, LateNight palette), Cambridge Audio (lunar-grey hi-fi restraint), FL Studio / VST synth UIs (neon accents).

Features #

Embedded daemon — if nothing is listening on 127.0.0.1:6061, the app boots a full in-process rockboxd via librockboxd.a (same archive the GPUI app links). If a daemon is already running it just connects.
Library browser — Albums grid (with cover art), Artists, Tracks, Liked; album detail page (art, year, label, track count, total duration, per-track play, shuffle).
Transport — play/pause, prev/next, seek, shuffle toggle, repeat cycle (off → all → one), and a rotary volume knob with percent readout, all synced with the daemon over gRPC streams.
VSCode-style panel toggles — two buttons at the top right (after search) show/hide the left navigation sidebar and the right queue panel; the icon is filled while its panel is visible.
Queue drawer — Play Queue / History tabs, pinned Now Playing card, Up Next list; click any row to jump (PlaylistService.Start).
Command palette — press / (or click the search box) for a Raycast-style overlay searching tracks, albums and artists; ↑/↓ + enter to play. ? shows the keyboard-shortcut help.
Audio settings — press e (or the sliders icon in the player bar): 10-band equalizer (enable switch, per-band vertical sliders, precut knob), Mixxx-style rotary knobs for bass / treble / balance / replaygain pre-amp / crossfade fade timings (drag vertically, scroll to nudge, double-click to reset), dropdowns for replaygain and crossfade modes, dithering toggle. Changes are coalesced and applied live via SettingsService.SaveSettings.
VFD display — jetAudio-style readout with elapsed time, codec, bitrate, sample rate and animated LED VU meters.
Server switcher — click the address at the bottom of the sidebar for a Raycast-style list: the embedded daemon, LAN rockboxd peers (mDNS, _rockbox._tcp), saved Subsonic/Jellyfin servers, or type host:port to connect to any remote rockboxd; switching re-points every gRPC stream live.
Playlists — create (name + description), edit, delete; add tracks via a Raycast-style picker; per-track remove; playlists appear in the / palette.
Remote servers — Subsonic/Navidrome and Jellyfin browsing/streaming via the daemon's navidrome:// / jellyfin:// browse schemes (Servers tab).
Skins — ten bundled (Synthwave default, plus Late Night, Neutron, Lunar, Nord, Oceanic, Tape, Phosphor and the two light ones, Porcelain and Parchment); press s or click the SKIN entry in the sidebar to cycle. The choice persists in ~/.config/rockbox.org/desktop-skin.

Build #

# Optional but recommended — embedded daemon support:
cd build-headless && make lib && cd ..
cargo build --release -p rockbox-embed -p rockbox-server
cd zig && zig build lib && cd ..          # → zig/zig-out/lib/librockboxd.a

# The app itself:
cd desktop && cargo build --release       # → target/release/rockbox-desktop

If librockboxd.a is absent the build still succeeds as a remote-only client (build.rs prints a warning); it then requires an externally started rockboxd.

Environment overrides: ROCKBOX_HOST, ROCKBOX_GRPC_PORT (6061), ROCKBOX_GRAPHQL_PORT (6062, used for /covers/ album art), ROCKBOX_HTTP_WORKERS (2, threads per embedded HTTP server), ROCKBOX_DB_MAX_CONNECTIONS (4, SQLite pool size per server thread).

Packaging #

bash desktop/package-macos.sh   # → desktop/dist/Rockbox.app + Rockbox.dmg
bash desktop/package-linux.sh   # → desktop/dist/usr/{bin,share}/…

package-macos.sh builds the icon from the shared appiconset, writes the Info.plist (including the NSLocalNetworkUsageDescription / NSBonjourServices entries the embedded daemon needs to see LAN devices on macOS 15+), ad-hoc signs the bundle and wraps it in a DMG with an /Applications symlink. That DMG is the release artifact and what the homebrew-tap cask installs. Pass SKIP_BUILD=1 to package an existing target/release/rockbox-desktop, and VERSION=… to stamp the bundle.

Skins #

A skin is a TOML file of design tokens — colors, radii, font families — that Rust loads into the Slint Theme global at runtime (src/skin.rs). Drop extra .toml files into ~/.config/rockbox.org/skins/ and they join the cycle; copy skins/synthwave.toml as a template. Malformed color values render loud magenta so they're easy to spot.

File	Vibe
`skins/synthwave.toml`	Neon magenta/cyan on deep violet (Serum / synthwave)
`skins/late-night.toml`	Mixxx LateNight PaleMoon — teal VFD, burnt amber
`skins/neutron.toml`	FL Studio graphite + signal orange, lime channel glow
`skins/lunar.toml`	Cambridge Audio lunar grey + warm lamp amber
`skins/nord.toml`	Nord polar slate, frost-blue display, aurora meters
`skins/oceanic.toml`	Deep-water teal hull, aqua phosphor, coral peaks
`skins/tape.toml`	Cassette deck — graphite, cream, burnt-orange VU
`skins/phosphor.toml`	Green-CRT rack gear on black; squared-off corners
`skins/porcelain.toml`	Light jetAudio silver deck, cool blue display
`skins/parchment.toml`	Light, warm — paper and ochre instead of silver

Architecture #

ui/app.slint         window, sidebar, views, player bar, overlays (palette,
                     help, queue drawer, album detail)
ui/components.slint  IconButton, PlayPauseButton, SlideBar, MeterStrip,
                     VfdDisplay, AlbumCard, TrackRow/TrackListHeader, …
ui/theme.slint       Theme global — every visual token, overwritten per skin
ui/icons.slint       Icons global — Lucide-style SVGs from assets/icons
assets/              self-contained: icons/*.svg, fonts/*.ttf, AppIcon.icns
                     (copies — never reference paths outside desktop/)
src/main.rs          UI-thread state (thread_local), callbacks, skin cycling
src/rpc.rs           tokio worker: tonic clients, StreamCurrentTrack /
                     StreamStatus / StreamPlaylist followers, command loop
src/skin.rs          skin TOML loading + Theme application + persistence
src/daemon.rs        embedded rockboxd boot (mirrors gpui/src/startup.rs)
build.rs             proto codegen (client-only), slint compile, conditional
                     librockboxd.a link (cfg: embedded_daemon)

Threading model: the tokio worker owns all gRPC I/O and pushes plain data to the UI thread with Weak::upgrade_in_event_loop; library state lives in a thread_local on the UI thread. UI callbacks send Cmd values over an unbounded channel back to the worker.

Icon rule: no emoji / Unicode glyphs as icons — only the SVGs referenced by ui/icons.slint (tinted via Image.colorize, so they follow every skin).