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subwave-nowplaying/README.md
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# subwave-nowplaying
Tronbyt/Tidbyt app showing the current track on a [SUB/WAVE](https://github.com/perminder-klair/subwave)
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 "<station> 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.