pub fn sync_track_fill(
tracks: Query<'_, '_, (&Toggleable, &TrackStyle, Has<Disabled>, &mut Visuals, &mut StyleOverrides)>,
)Expand description
Paint every <toggle> / <switch> track with the fill its current
state calls for. This is the single owner of a track’s
Visuals::fill; the per-widget sync systems only move the knob.
The state fill is held in StyleOverrides under the hover and press
tints, so a tint blends from it and lets go onto it, and a restyle
keeps it: state, not the cascade, decides what a track shows. It runs
every tick rather than on Changed<Toggleable>, because the state is
not the only thing that moves the fill: a restyle recomputes the
TrackStyle palette on a theme or media flip. Writes happen only
when the fill differs, so an idle frame still triggers no change
detection.