v0.27.1

ui! widgets accept on EventKind { body } for inline gesture handlers, with two unambiguous positions: between attrs and children body (Form C), or as a modifier chain after the widget (Form B). The seven GestureEvent variants are routed by name; multi-tap is supported on Tap via a new MultiTapTracker resource with a 300ms window.

Added

• Widget() on EventKind { body } { children } (Form C, inline) — on lives between attrs and children body. Multiple on clauses stack on the same widget.
• Widget() {} on EventKind { body } (Form B, modifier chain) — on follows a fully-parsed widget. Inside a nested body, on attaches to the nearest preceding sibling widget. Multiple on clauses chain.
• Mixed Form B + Form C on the same widget — all on clauses collect into one dispatch fn, regardless of their position.
• on Tap(n) multi-tap — n ∈ {1, 2, 3} routes by MultiTapTracker::current_count. on Tap and on Tap(2) coexist on the same widget; the dispatch fn picks the matching arm at fire time.
• MultiTapTracker resource — bubble_dispatch_at lazy-inserts the resource on the first Tap. The 300ms window is MULTI_TAP_WINDOW_MS. now_ms == 0 is the "no clock available" sentinel and never accumulates count.
• bubble_dispatch_at(world, event, now_ms) — clock-aware dispatch; bubble_dispatch delegates to it with now_ms = 0. The real input loop in App::run uses the live monotonic clock.
• Auto-destructured fields in handler bodies — x, y, dx, dy, vx, vy, scale_delta, angle, target are all in scope as appropriate for the matched event variant. __world: &mut World and __entity: Entity are also bound.
• trybuild fixtures for ui! diagnostics: on_form_a_inside_body.rs (rejects Widget() { on EventKind {} } with a clear error), on_non_tap_with_args.rs, on_qualified_path.rs, on_unknown_event.rs.
• gallery/examples/on_handlers_demo.rs — four colour-coded boxes with on Tap / on Tap(2) / on Tap(3) / on LongPress in modifier-chain form, a label above counts each kind.

Notes

• Bodies default to true (consume the event); explicit return false lets bubble_dispatch keep walking.
• On Component widgets (Button, Slider, etc.) the user on EventKind dispatch fn replaces the component's internal GestureHandler — same single-handler ECS semantics that already governed manual world.insert(GestureHandler { ... }).
• on Path::EventKind qualified form parses but raises a compile error pointing users at the unqualified form. Non-Tap events with parameters (on LongPress(500) etc.) compile-error too.

Internal

• xrune dependency: 1.5.1 (1.5.0 yanked). DsRune::inscribe_widget now takes on_handlers: &[DsOn] for the on-clauses attached to the widget; DsRune::inscribe_on is removed.