subwave-nowplaying/README.md

subwave-nowplaying

Tronbyt/Tidbyt app showing the current track on a SUB/WAVE internet radio station: album art, track title/artist (scrolling), a thin separator, the current show and host, and a full-width footer with time/temperature and a track progress bar pinned to the bottom edge. Color scheme (cyan title/artist, white show name, magenta host/progress bar) is loosely modeled on SUB/WAVE's own web now-playing display.

Not tied to any specific station — set your own station's base URL in the app's config when adding it to a device.

Configuration

• Station URL — the base URL of your SUB/WAVE instance, e.g. https://radio.example.com. No trailing slash needed (stripped automatically). No auth required — SUB/WAVE's now-playing and cover-art endpoints are public.

How it works

• GET {station_url}/api/now-playing — track title, artist, subsonic_id, DJ/station name, and stream online status. Cached 20s.
• GET {station_url}/api/cover/{subsonic_id} — album art JPEG, proxied by SUB/WAVE itself (no Navidrome credentials needed). Cached 300s.
• If the station reports streamOnline: false, shows " offline" instead of stale track info.
• If a track has no subsonic_id, or the cover fetch fails, falls back to a full-width layout with no art rather than a broken image.
• Shows the current show name (context.activeShow.name) and host name (dj.name) below the artist, separated by a thin divider line.
• Shows the local time and temperature (context.clock/context.weather) and the track progress bar as a full-width (64px) footer overlaid on the bottom of the layout — not confined to the 32px-wide text column, which gives roughly 2x the character budget for the time/temp line (at the cost of covering the bottom ~9px of the album art with a translucent bar).

Why show/host/time-temp are plain Text, not Marquee: pixlet's Marquee runs its own internal scroll-cycle animation regardless of whether the text actually needs to scroll, and combining multiple Marquees with very different cycle lengths in one Root desyncs them — confirmed via an isolated repro where a short Marquee'd line intermittently collapsed to a single character on frames where the long title/artist marquees were mid-cycle. Only title/artist (which actually benefit from scrolling for long names) use Marquee; the shorter supplementary fields use plain Text/Row and just clip if too wide, which is an acceptable tradeoff.

Progress bar caveat: the now-playing API reports track duration but not elapsed/remaining time, so the app tracks playback position itself — the first time it sees a given subsonic_id, it stamps the current wall-clock time in pixlet's cache, then diffs against that stamp on later renders to compute elapsed seconds. This only works correctly on a long-lived server process with a persistent cache (true for tronbyt/server's in-memory cache) — a one-shot pixlet render CLI invocation always starts a fresh process with an empty cache, so the bar will always show 0% when testing locally. This is expected, not a bug.

Note on unreachable hosts: if the station URL is wrong or the host is completely unreachable (DNS failure, connection refused), http.get raises a hard error and the render fails for that cycle — this is normal pixlet/ Starlark behavior (no try/except in the language), not a bug. Only HTTP-level errors (404, 500, etc.) are something the app can catch and display a message for, which it does.

Dev/test

pixlet render subwave_nowplaying.star station_url=https://your-station.example.com
pixlet serve subwave_nowplaying.star

Deploy

Upload subwave_nowplaying.star directly through your Tronbyt server's "Upload app" button on a device's Add App page (single file, no bundled assets — no need to zip). Configure the Station URL field when adding it to your device's schedule.