# UI-03 — Shared floating-glass component kit

**Depends on** UI-08 (theme tokens) · **Size** M · **Status** Done

## Goal
Build once, use everywhere: the small set of visual primitives every Stitch screen
reuses, so UI-04/05/06/07 compose them instead of each reinventing blur-panel styling.

## Context
All four Stitch exports lean on the same handful of visual patterns repeatedly:
glassmorphic panels (`bg-surface/80 backdrop-blur-xl border border-white/10`), a floating
centered pill for a compact stat summary, and a pulsing/radar-style location marker.
Building these once means every consuming screen ticket is "compose these," not
"reimplement blur and border styling a fourth time."

## Design
Three widgets, all pure presentation (no data-fetching, no business logic):

**`GlassPanel`** — the workhorse. `BackdropFilter` + `ImageFilter.blur` inside a
`ClipRRect`, a translucent surface-color fill, a 1px low-opacity border. Takes a `child`
and behaves like a styled `Container`. Every floating card, tooltip, and control in the
redesign is one of these underneath.

**`FloatingPill`** — a `GlassPanel` shaped as a horizontally-centered, rounded-full
capsule holding a row of labeled stat columns (see Route Planning's Distance/Est. Time/
Pins header). Takes a list of `(label, value)` pairs and lays them out with vertical
dividers between them, matching the Stitch export exactly.

**`PulsingLocationMarker`** — the expanding-ring-plus-glow-dot from the Plan/Route
Planning exports. A `CustomPainter` or layered `AnimatedContainer`s driving an
`AnimationController` in a loop (scale 0.8→1.0, opacity 0.8→0, repeating) — respect
`MediaQuery.disableAnimations`/`prefers-reduced-motion` equivalent by falling back to a
static dot when animations are disabled system-wide.

## Implementation
1. `lib/src/ui/components/glass_panel.dart` — `GlassPanel`, with blur radius, fill
   opacity, and border opacity as named constants (not magic numbers scattered per call
   site), sourced from UI-08's theme tokens.
2. `lib/src/ui/components/floating_pill.dart` — `FloatingPill`, built on `GlassPanel`.
3. `lib/src/ui/components/pulsing_location_marker.dart` — `PulsingLocationMarker`,
   wrapping its `AnimationController` lifecycle correctly (dispose on unmount, same
   discipline as `RideMap`'s existing lifecycle observer from V3-04).
4. Widget tests render each in isolation against both themes (if UI-08 keeps a light
   variant) to catch a black-on-black-style contrast regression early, the same
   discipline V3-16 established.

## Acceptance criteria
- [ ] `GlassPanel` renders a blurred, bordered, translucent container matching the
      Stitch reference visually
- [ ] `FloatingPill` renders an arbitrary number of stat columns with dividers between
      them, not hardcoded to exactly three
- [ ] `PulsingLocationMarker` animates continuously without leaking its
      `AnimationController` across widget rebuilds or disposal
- [ ] Reduced-motion setting is respected by `PulsingLocationMarker`

## Tests
- Widget: each component renders with representative content and takes a screenshot-
  comparable snapshot of its structure (no golden files per V3-16's precedent — assert
  structure/color, not pixels)
- Widget: `PulsingLocationMarker`'s animation controller is disposed when the widget is
  removed from the tree (a `flutter_test` pending-timer/ticker check, mirroring the
  Drift stream-query keep-alive pattern already documented in `widget_test.dart`)

## Risks
- `BackdropFilter` is one of the more expensive Flutter widgets to composite; stacking
  several `GlassPanel`s over a live, animating map (per UI-01/UI-02) could visibly cost
  frame time on lower-end devices. Worth a real-device check once UI-05 assembles them
  together, not just in isolation.

## Out of scope
The customizable drag/resize telemetry widgets (UI-04) — those consume `GlassPanel` as
their visual shell but the interaction logic is a separate, larger ticket.

## Outcome

All three values (blur radius, opacities, dimensions, colors) were lifted directly from
the Route Planning export's own glass treatment and `pulse-ring` keyframes rather than
guessed — `docs/design/stitch-export/screens/route-planning-dark.html`'s `bg-surface/90
backdrop-blur-xl border border-outline-variant/30` and its `@keyframes pulse-ring`
(scale 0.8→1.0, opacity 0.8→0, eased) map directly onto `GlassPanel.blurSigma`/
`fillOpacity`/`borderOpacity` and `PulsingLocationMarker`'s animation curve.

`GlassPanel` (`lib/src/ui/components/glass_panel.dart`) is `ClipRRect > BackdropFilter >
DecoratedBox`, taking `child`/`borderRadius`/`padding` and reading its fill/border colors
from the theme (`colors.surface`, `colors.outlineVariant` — the latter newly added to
`ripprColors` in `theme.dart` for this ticket, since UI-08 hadn't needed it before now).
`FloatingPill` (`floating_pill.dart`) is a `GlassPanel` shaped as a stadium capsule
around a `Row` of `PillStat` columns with 1px dividers between them — genuinely
arbitrary-length, not hardcoded to three, verified by a 4-stat test case.
`PulsingLocationMarker` (`pulsing_location_marker.dart`) layers a static faint ring, an
animated expanding-and-fading ring, and a glowing center dot; it checks
`MediaQuery.disableAnimations` in `didChangeDependencies` (not `initState`, which
Flutter forbids for inherited-widget lookups) and stops the controller entirely when
reduced motion is requested, falling back to a static dot.

**Test-writing bug caught and fixed:** the first version of the "legible in both
themes" test pumped `ripprTheme()` then `ripprMountedTheme()` sequentially in a single
`testWidgets` loop. Because both produced an identically-shaped widget tree
(`MaterialApp > Scaffold > GlassPanel > Text`), Flutter reused the first pump's elements
across the second `pumpWidget` call rather than rebuilding fresh, so the second
iteration silently re-read the *first* theme's already-resolved paint color — the test
would have falsely failed for a real theme-following bug and, worse, could have
falsely passed one due to reading stale data. Split into two independent `testWidgets`
blocks instead, which is the correct way to exercise two themes against the same
component.

**Tests:** `flutter analyze` clean. `flutter test` green at 336 tests (328 + 8 new in
`test/glass_component_kit_test.dart`): `GlassPanel`'s blur/translucency/border
structure and its resolved-paint-color contrast in both themes; `FloatingPill`'s
divider count scaling with stat count (and the zero-divider single-stat case);
`PulsingLocationMarker`'s continuous animation, correct `AnimationController` disposal
on removal (caught automatically by `flutter_test`'s own ticker-leak check, not a
manual timer assertion), and the reduced-motion fallback.

**Android emulator verification**: no consuming screen exists yet (that's UI-04/05/06),
so verification used a throwaway preview entry point
(`lib/main_ui03_preview.dart`, deleted after use) rendering all three components over a
map-colored gradient background. All three matched the Stitch reference's look: the
`FloatingPill`'s blur/translucency/dividers/blue values rendered crisply; the
`PulsingLocationMarker`'s glow and ring were visible and animating. One red herring
during this check: `GlassPanel`'s content briefly appeared to render illegibly when the
preview used `Theme.of(context).textTheme.headlineSmall` for a heading, despite that
style's `color` property independently verified (via a debug test) to already be the
correct ink value with full alpha. Switching to an explicit inline `TextStyle` (no
ambient text-theme role) rendered crisply instead. This was isolated to the scratch
preview file, not `GlassPanel` itself — the shipped components' own tests all render
content through explicit styles or the already-verified `bodyMedium` role, the same
discipline every real screen in this codebase already follows — but it's worth flagging
as a `headlineSmall`-specific rendering quirk to watch for if UI-05/06 lean on that
particular text-theme role for real headings.

## Risks note (revisited)

The ticket's own risk — `BackdropFilter` compositing cost when several `GlassPanel`s
stack over a live, animating map — was not measurable in this ticket's isolated preview
(no map, no stacking). Deferred to UI-05, as the ticket itself anticipated, where the
Record screen actually assembles multiple glass panels over `RideMap`.