S4 of the lyrics epic: ms-precision position source, 30Hz sync engine,
word-anchored karaoke fill, auto-centered ladder scroll, QConnect peer
following.
- qbz-player: read-only SharedState::current_position_ms() derived from
the existing playback_start_millis/position_at_start anchors (Q1; no
stream/seek/format path touched) + unit test
- qbz-lyrics: new sync module porting the Tauri active-line math (binary
search active index, per-line progress with the 0.99 snap) plus the
word-anchored clip fraction for Qobuz wsync lines (char-proportional
word width approximation, Q2); unit tests
- qbz-slint: lyrics_sync engine - adaptive slint::Timer (33ms while
panel open + synced + playing, 250ms gate polling otherwise),
equality-guarded pushes, fill animation zeroed across discontinuities
(line change / backward seek); kick() on doc commit and panel open
- QConnect (Q7): the poll loop controller branch publishes the raw
renderer anchor; the engine extrapolates it per tick so lyrics follow
the peer (Tauri freezes); local fallthrough clears the anchor
- LyricsLinesView: karaoke fill via clipped bright overlay text over the
dim base (rect-clip approximation, D5); auto-center scroll from
layout-relative active-row geometry, smooth for <=2-line moves and
instant for jumps/initial sync, animated via a separate scroll-target
property so user wheel input is never animated
- LyricsState: line-progress + fill-anim-ms properties
cc
vicrodh
5f9fd5bdd6