uosc timeline ported from uosc (hatching on the uncached part, line marker, remaining time, buffered label, diamonds); mouse wheel sets the volume anywhere on the video, with a volume readout

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

apps/desktop/lib/src/controls/uosc/buttons.dart

@@ -1,4 +1,3 @@
-import 'package:flutter/gestures.dart';
 import 'package:flutter/material.dart';
 import 'package:signals/signals_flutter.dart';
 import 'package:sync_relay_core/core.dart' show JellyfinStreamType;
@@ -168,7 +167,7 @@ class _UoscBadgeButtonState extends State<UoscBadgeButton> {
 }
 
 /// Volume: click mutes / unmutes, hovering shows a [VolumeBar] up to
-/// [maxVolume], the wheel steps 5 %.
+/// [maxVolume], the wheel steps [volumeStep].
 class UoscVolumeButton extends StatefulWidget {
   /// 0..[maxVolume].
   final double volume;
@@ -180,6 +179,7 @@ class UoscVolumeButton extends StatefulWidget {
 }
 
 class _UoscVolumeButtonState extends State<UoscVolumeButton> {
+  final _steps = WheelSteps();
   double _beforeMute = 100;
   bool _hover = false;
 
@@ -191,11 +191,8 @@ class _UoscVolumeButtonState extends State<UoscVolumeButton> {
       onEnter: (_) => setState(() => _hover = true),
       onExit: (_) => setState(() => _hover = false),
       child: Listener(
-        onPointerSignal: (e) {
-          if (e is PointerScrollEvent && e.scrollDelta.dy != 0) {
-            widget.onChanged(stepVolume(v, e.scrollDelta.dy < 0 ? 5 : -5));
-          }
-        },
+        // Claimed here, so the player's own wheel handler skips it.
+        onPointerSignal: (e) => _steps.handle(e, (step) => widget.onChanged(stepVolume(v, step * volumeStep))),
         child: Row(
           mainAxisSize: MainAxisSize.min,
           children: [

apps/desktop/lib/src/controls/uosc/controls.dart

@@ -10,8 +10,8 @@ import '../controls_probe.dart' show ControlsHold;
 // bottom with a row of flat buttons above it, the title top left and a
 // corner widget top right.
 // Mouse movement shows them; after [UoscControls.hideAfter] without any
-// they fade out, the timeline shrinks to a 2 px line (gone when "Progress
-// line when hidden" is off) and the cursor hides. Our own frame: no
+// they fade out, the timeline shrinks to uosc's progress line (gone when
+// "Progress line when hidden" is off) and the cursor hides. Our own frame: no
 // media_kit controls state to reach into.
 
 class UoscControls extends StatefulWidget {

apps/desktop/lib/src/controls/uosc/style.dart

@@ -4,9 +4,7 @@ import 'package:flutter/material.dart';
 // owner runs it: flat black panels, white icons, a muted blue fill.
 
 abstract final class UoscStyle {
-  /// Timeline background and the boxes on it.
-  static const bar = Color(0xCC000000);
-  /// Played part of the timeline; also the active menu row.
+  /// The active menu row.
   static const fill = Color(0xFF4C6A8E);
   /// Menus and tooltips.
   static const panel = Color(0xF0101010);
@@ -51,8 +49,8 @@ class UoscTooltip extends StatelessWidget {
   }
 }
 
-/// A small dark box with one line of text (the timeline's times, the
-/// hover chapter title).
+/// A small dark box with one line of text (the timeline's hover time and
+/// chapter title).
 class UoscBox extends StatelessWidget {
   final String text;
   final Color color;

apps/desktop/lib/src/controls/uosc/timeline.dart

@@ -1,3 +1,4 @@
+import 'dart:async';
 import 'dart:math' as math;
 
 import 'package:flutter/material.dart';
@@ -6,6 +7,66 @@ import '../../playback/media_marks.dart';
 import 'controls.dart';
 import 'style.dart';
 
+// A port of uosc's timeline (`elements/Timeline.lua`, defaults from
+// `uosc.conf` / `main.lua`), style `line`, scale 1: a translucent black
+// band, the position a thin white line (no filled progress), the
+// uncached part hatched, chapter diamonds on the top edge, elapsed time
+// left and the time remaining right, the buffered seconds next to the
+// position while under the threshold, and a tooltip with the time (and
+// the chapter title) under the mouse.
+
+/// uosc's defaults at scale 1.
+abstract final class UoscTimelineSpec {
+  /// `timeline_size`: the band's height when expanded.
+  static const size = 40.0;
+
+  /// `timeline_border`: band above the line, also the diamonds' border.
+  static const border = 1.0;
+
+  /// `timeline_line_width`: the position line.
+  static const lineWidth = 2.0;
+
+  /// `progress_size`: what is left when the controls hide.
+  static const progressSize = 2.0;
+
+  /// `progress_line_width`: the position line once minimized.
+  static const progressLineWidth = 20.0;
+
+  /// floor(min((size + 60) * 0.2, size * 0.96)).
+  static const fontSize = 20.0;
+
+  /// max(floor((size - fontSize) / 2.5), 4): the times' inset.
+  static const spacing = 8.0;
+
+  /// `text_border`: the outline of text drawn on the band.
+  static const textBorder = 1.2;
+
+  /// `opacity.timeline` (the band) and `opacity.chapters` (diamond fill).
+  static const opacity = 0.9;
+  static const chaptersOpacity = 0.8;
+
+  /// Gap between the band and its tooltips, and between tooltips.
+  static const tooltipGap = 2.0;
+
+  /// `buffered_time_threshold`: the cache label shows below this.
+  static const bufferedThreshold = Duration(seconds: 60);
+
+  /// max((size + border) / 10, 3): diamond radius cap.
+  static const chapterSize = (size + border) / 10;
+}
+
+/// uosc's `format_time(seconds, duration)`: mpv's "HH:MM:SS", trimmed to
+/// "MM:SS" for media under an hour and "SS" under a minute; negative
+/// values keep their minus ("-01:47:30").
+String uoscClock(Duration d, Duration max) {
+  final neg = d.isNegative && d.inSeconds != 0;
+  final t = d.abs();
+  String two(int n) => n.toString().padLeft(2, '0');
+  final full = '${two(t.inHours)}:${two(t.inMinutes % 60)}:${two(t.inSeconds % 60)}';
+  final trim = max < const Duration(minutes: 1) ? 6 : (max < const Duration(hours: 1) ? 3 : 0);
+  return '${neg ? '-' : ''}${full.substring(trim)}';
+}
+
 /// Fraction of [total] at [d], 0..1 (0 without a duration).
 double timelineFraction(Duration d, Duration total) {
   final t = total.inMicroseconds;
@@ -13,36 +74,104 @@ double timelineFraction(Duration d, Duration total) {
   return (d.inMicroseconds / t).clamp(0.0, 1.0);
 }
 
-/// The cached-ahead part of a timeline of [size]: from the playing
-/// position to the end of mpv's cache. Null when nothing is cached ahead.
-Rect? cacheRect(Size size, {required Duration position, required Duration buffered, required Duration duration}) {
-  final from = timelineFraction(position, duration) * size.width;
-  final to = timelineFraction(buffered, duration) * size.width;
-  if (to - from < 0.5) return null;
-  return Rect.fromLTRB(from, 0, to, size.height);
+/// Where the uncached part starts (it runs to the end), as a fraction;
+/// null when nothing known is uncached. We know only the end of mpv's
+/// cache ahead ([buffered]); without it (0) uosc draws no ranges either,
+/// and a cache that reaches the end (within uosc's 0.5 s) leaves none.
+double? uncachedFrom({required Duration position, required Duration buffered, required Duration duration}) {
+  if (duration <= Duration.zero || buffered <= Duration.zero) return null;
+  final from = buffered > position ? buffered : position;
+  if (duration - from <= const Duration(milliseconds: 500)) return null;
+  return timelineFraction(from, duration);
 }
 
-/// The hatching of [r]: 45° strokes from bottom-left to top-right,
-/// [spacing] apart along x, across all of [r] (the painter clips them).
-/// The first starts half a step in, so none just grazes the corner.
-List<(Offset, Offset)> hatchLines(Rect r, {double spacing = 6}) {
-  if (r.isEmpty || spacing <= 0) return const [];
-  final h = r.height;
-  return [
-    for (var x = r.left - h + spacing / 2; x < r.right; x += spacing) (Offset(x, r.bottom), Offset(x + h, r.top)),
-  ];
+/// The cache label next to the position ("12s"): the seconds buffered
+/// ahead, shown while under [UoscTimelineSpec.bufferedThreshold] and the
+/// cache does not reach the end (uosc drops it at eof-cached).
+String? cacheLabel({required Duration position, required Duration buffered, required Duration duration}) {
+  if (duration <= Duration.zero || buffered <= Duration.zero) return null;
+  if (duration - buffered <= const Duration(milliseconds: 500)) return null;
+  final ahead = buffered > position ? buffered - position : Duration.zero;
+  if (ahead >= UoscTimelineSpec.bufferedThreshold) return null;
+  return '${(ahead.inMilliseconds / 1000).round()}s';
 }
 
-/// The uosc timeline: full width, elapsed part filled, the cached range
-/// ahead hatched, chapter starts as white diamonds on the top edge, the
-/// current time in a box at the left and the duration at the right.
-/// Hover shows the chapter title over the hover time. When the controls
-/// hide ([expanded] false) it shrinks to a thin line with chapter ticks.
-/// Like the media_kit bar it reports a seek on every drag move and on
-/// release ([onSeek]); the session sends those through the user-seek path.
+/// The band's geometry at one size, as uosc lays it out: the position
+/// line takes [lineWidth] pixels, and times map around it (`t2x`) so no
+/// time lies inside the line.
+class UoscTimelineGeometry {
+  final double width;
+
+  /// The foreground height (without the top border).
+  final double size;
+
+  /// The playing position, 0..1.
+  final double progress;
+  final double lineWidth;
+  const UoscTimelineGeometry({
+    required this.width,
+    required this.size,
+    required this.progress,
+    this.lineWidth = UoscTimelineSpec.lineWidth,
+  });
+
+  /// [size] while the band animates between hidden (0) and shown (1)
+  /// (`get_effective_size`).
+  static double sizeAt(double visibility) =>
+      UoscTimelineSpec.progressSize +
+      ((UoscTimelineSpec.size - UoscTimelineSpec.progressSize) * visibility).ceilToDouble();
+
+  /// The position line's width at [size]: it grows to
+  /// [UoscTimelineSpec.progressLineWidth] over the last eighth of the
+  /// collapse.
+  static double lineWidthAt(double size) {
+    const p = UoscTimelineSpec.progressSize;
+    final minimized = 1 - math.min((size - p) / ((UoscTimelineSpec.size - p) / 8), 1.0);
+    return UoscTimelineSpec.lineWidth + (UoscTimelineSpec.progressLineWidth - UoscTimelineSpec.lineWidth) * minimized;
+  }
+
+  double get height => size + UoscTimelineSpec.border;
+
+  /// Top of the foreground (below the border).
+  double get top => UoscTimelineSpec.border;
+  double get lineLeft => ((width - lineWidth) * progress).roundToDouble();
+  double get lineRight => ((width - lineWidth) * progress + lineWidth).roundToDouble();
+
+  /// x of [fraction] (uosc's `t2x`): past the position, shifted over the line.
+  double x(double fraction) {
+    final lw = lineWidth - 1;
+    final at = 0.5 + (width - lw - 1) * fraction;
+    return fraction <= progress ? at : at + lw;
+  }
+
+  /// The fraction at [x] (uosc's `get_time_at_x`): x on the line is the
+  /// position.
+  double fractionAt(double x) {
+    const lw = UoscTimelineSpec.lineWidth - 1;
+    final timeWidth = width - lw - 1;
+    if (timeWidth <= 0) return 0;
+    final a = timeWidth * progress, b = a + lw;
+    var at = x - 0.5;
+    if (at > b) {
+      at -= lw;
+    } else if (at > a) {
+      at = a;
+    }
+    return (at / timeWidth).clamp(0.0, 1.0);
+  }
+
+  /// Chapter diamond radius at this size; doubled while hovered.
+  double get diamondRadius => math.min(math.max(1.0, size * 0.8), UoscTimelineSpec.chapterSize);
+}
+
+/// The uosc timeline. [expanded] false (the controls hidden) shrinks it,
+/// animated, to the progress line. Seeks ([onSeek]) on press, on every
+/// drag move and on release; a press on a hovered chapter diamond jumps
+/// to that chapter. The session sends those through the user-seek path.
 class UoscTimeline extends StatefulWidget {
   final Duration position;
   final Duration duration;
+
   /// End of the cached range ([PlaybackController.buffered]).
   final Duration buffered;
   final List<MediaChapter> chapters;
@@ -58,24 +187,32 @@ class UoscTimeline extends StatefulWidget {
     required this.onSeek,
   });
 
-  static const height = 30.0;
-  static const collapsedHeight = 2.0;
+  static const height = UoscTimelineSpec.size + UoscTimelineSpec.border;
+  static const collapsedHeight = UoscTimelineSpec.progressSize + UoscTimelineSpec.border;
+
+  /// uosc's `animation_duration`.
+  static const animation = Duration(milliseconds: 100);
 
   @override
   State<UoscTimeline> createState() => _UoscTimelineState();
 }
 
 class _UoscTimelineState extends State<UoscTimeline> {
-  double? _hoverX;
+  Offset? _hover;
   bool _dragging = false;
   double _dragFraction = 0;
+  Duration? _lastSent;
+  // A released seek, shown until the position catches up (else the line
+  // jumps back to the old position for a moment).
+  double? _pending;
+  Timer? _pendingTimer;
 
   Duration _at(double fraction) => widget.duration * fraction.clamp(0.0, 1.0);
 
-  void _seekTo(double x, double width) {
-    if (widget.duration <= Duration.zero || width <= 0) return;
-    _dragFraction = (x / width).clamp(0.0, 1.0);
-    widget.onSeek(_at(_dragFraction));
+  void _send(Duration d) {
+    if (d == _lastSent) return;
+    _lastSent = d;
+    widget.onSeek(d);
   }
 
   void _drag(bool on) {
@@ -84,204 +221,425 @@ class _UoscTimelineState extends State<UoscTimeline> {
     UoscControls.maybeOf(context)?.hold(on);
   }
 
+  void _settle(double fraction) {
+    _pending = fraction;
+    _pendingTimer?.cancel();
+    _pendingTimer = Timer(const Duration(seconds: 2), () {
+      if (mounted) setState(() => _pending = null);
+    });
+  }
+
   @override
   void didUpdateWidget(UoscTimeline old) {
     super.didUpdateWidget(old);
-    if (!widget.expanded && old.expanded) _hoverX = null;
+    if (!widget.expanded && old.expanded) _hover = null;
+    final p = _pending;
+    if (p != null && widget.duration > Duration.zero) {
+      final off = (widget.position - _at(p)).abs();
+      if (off < const Duration(milliseconds: 1500)) {
+        _pending = null;
+        _pendingTimer?.cancel();
+      }
+    }
   }
 
   @override
   void dispose() {
+    _pendingTimer?.cancel();
     // A drag cut short by a rebuild must not keep the controls up.
     if (_dragging) UoscControls.maybeOf(context)?.hold(false);
     super.dispose();
   }
 
+  /// The chapter whose diamond is within twice its radius of [at].
+  int? _hoveredChapter(UoscTimelineGeometry geo, List<MediaChapter> marks, Offset? at) {
+    if (at == null || _dragging) return null;
+    final reach = geo.diamondRadius * 2;
+    int? best;
+    var bestD = double.infinity;
+    for (var i = 0; i < marks.length; i++) {
+      final cx = geo.x(timelineFraction(marks[i].start, widget.duration));
+      final d = (Offset(cx, 0) - at).distance;
+      if (d <= reach && d < bestD) {
+        best = i;
+        bestD = d;
+      }
+    }
+    return best;
+  }
+
   @override
   Widget build(BuildContext context) {
-    return LayoutBuilder(builder: (context, constraints) {
-      final width = constraints.maxWidth;
-      final expanded = widget.expanded;
-      final h = expanded ? UoscTimeline.height : UoscTimeline.collapsedHeight;
-      final played = _dragging ? _dragFraction : timelineFraction(widget.position, widget.duration);
-      final hoverX = expanded ? _hoverX : null;
-      final hoverAt = hoverX == null || width <= 0 ? null : _at(hoverX / width);
-      final hoverChapter = hoverAt == null ? null : chapterIndexAt(widget.chapters, hoverAt);
-      final hoverTitle = hoverChapter == null ? '' : widget.chapters[hoverChapter].title;
-      final withHours = widget.duration >= const Duration(hours: 1);
-      final marks = [
-        for (final c in widget.chapters)
-          if (c.start > Duration.zero && widget.duration > Duration.zero) c,
-      ];
-      final bar = SizedBox(
-        key: const ValueKey('uosc-timeline'),
-        width: width,
-        height: h,
-        child: Stack(
-          clipBehavior: Clip.none,
-          children: [
-            Positioned.fill(
-              child: CustomPaint(
-                painter: UoscTimelinePainter(
-                  played: played,
-                  cache: (size) => cacheRect(size,
-                      position: widget.position, buffered: widget.buffered, duration: widget.duration),
-                  cacheKey: (widget.position, widget.buffered, widget.duration),
-                  hoverX: _dragging ? null : hoverX,
-                  hatched: expanded,
+    final font = DefaultTextStyle.of(context).style.fontFamily ?? Theme.of(context).textTheme.bodyMedium?.fontFamily;
+    return LayoutBuilder(
+      builder: (context, constraints) {
+        final width = constraints.maxWidth;
+        return TweenAnimationBuilder<double>(
+          tween: Tween(end: widget.expanded ? 1 : 0),
+          duration: UoscTimeline.animation,
+          builder: (context, visibility, _) => _band(width, visibility, font),
+        );
+      },
+    );
+  }
+
+  Widget _band(double width, double visibility, String? font) {
+    final expanded = widget.expanded;
+    final duration = widget.duration;
+    final size = UoscTimelineGeometry.sizeAt(visibility);
+    final progress = _dragging ? _dragFraction : (_pending ?? timelineFraction(widget.position, duration));
+    final shown = _at(progress);
+    final geo = UoscTimelineGeometry(
+      width: width,
+      size: size,
+      progress: progress,
+      lineWidth: UoscTimelineGeometry.lineWidthAt(size),
+    );
+    final marks = duration > Duration.zero ? widget.chapters : const <MediaChapter>[];
+    final hover = expanded ? _hover : null;
+    final hovered = _hoveredChapter(geo, marks, hover);
+    final hoverFraction = hovered != null
+        ? timelineFraction(marks[hovered].start, duration)
+        : (hover == null || duration <= Duration.zero ? null : geo.fractionAt(hover.dx));
+    final hoverAt = hoverFraction == null ? null : _at(hoverFraction);
+    final cursorX = hovered != null ? geo.x(hoverFraction!) : hover?.dx;
+    final hoverChapter = hoverAt == null ? null : chapterIndexAt(widget.chapters, hoverAt);
+    final hoverTitle = hoverChapter == null ? '' : widget.chapters[hoverChapter].title;
+    // Text fades out just before it would overflow the shrinking band.
+    const hideBelow = UoscTimelineSpec.fontSize * 0.8;
+    final textOpacity = (size - hideBelow).clamp(0.0, hideBelow / 2) / (hideBelow / 2);
+    final radius = geo.diamondRadius;
+    final timestampGap = UoscTimelineSpec.tooltipGap + (hovered != null ? radius * 2 : radius).roundToDouble();
+    final painter = UoscTimelinePainter(
+      geometry: geo,
+      visibility: visibility,
+      uncached: uncachedFrom(position: widget.position, buffered: widget.buffered, duration: duration),
+      chapters: [for (final c in marks) timelineFraction(c.start, duration)],
+      hoveredChapter: hovered,
+      hoverX: cursorX,
+      textOpacity: textOpacity,
+      elapsed: duration > Duration.zero ? uoscClock(shown, duration) : null,
+      remaining: duration > Duration.zero ? uoscClock(shown - duration, duration) : null,
+      cache: cacheLabel(position: widget.position, buffered: widget.buffered, duration: duration),
+      fontFamily: font,
+    );
+    final bar = SizedBox(
+      key: const ValueKey('uosc-timeline'),
+      width: width,
+      height: geo.height,
+      child: Stack(
+        clipBehavior: Clip.none,
+        children: [
+          Positioned.fill(
+            child: RepaintBoundary(child: CustomPaint(painter: painter)),
+          ),
+          if (hoverAt != null && cursorX != null)
+            Positioned(
+              left: 0,
+              right: 0,
+              bottom: geo.height + timestampGap,
+              height: 160,
+              child: IgnorePointer(
+                child: CustomMultiChildLayout(
+                  delegate: _TooltipLayout(x: cursorX),
+                  children: [
+                    LayoutId(
+                      id: #time,
+                      child: UoscBox(
+                        uoscClock(hoverAt, duration),
+                        key: const ValueKey('uosc-hover-time'),
+                        color: Colors.black,
+                        style: _tipStyle,
+                      ),
+                    ),
+                    if (hoverTitle.isNotEmpty)
+                      LayoutId(
+                        id: #chapter,
+                        child: UoscBox(
+                          hoverTitle,
+                          key: const ValueKey('uosc-hover-chapter'),
+                          color: Colors.black,
+                          style: _tipStyle.copyWith(fontWeight: FontWeight.bold),
+                        ),
+                      ),
+                  ],
                 ),
               ),
             ),
-            for (final c in marks)
-              if (expanded)
-                Positioned(
-                  key: ValueKey('uosc-chapter-${c.index}'),
-                  left: width * timelineFraction(c.start, widget.duration) - 4,
-                  top: -4,
-                  width: 8,
-                  height: 8,
-                  child: IgnorePointer(
-                    child: Transform.rotate(
-                      angle: math.pi / 4,
-                      child: Container(
-                        margin: const EdgeInsets.all(1.2),
-                        decoration: BoxDecoration(
-                          color: Colors.white,
-                          border: Border.all(color: Colors.black54, width: 0.6),
-                        ),
-                      ),
-                    ),
-                  ),
-                )
-              else
-                Positioned(
-                  key: ValueKey('uosc-chapter-tick-${c.index}'),
-                  left: width * timelineFraction(c.start, widget.duration) - 1,
-                  top: -2,
-                  width: 2,
-                  height: h + 2,
-                  child: const IgnorePointer(child: ColoredBox(color: Colors.white70)),
-                ),
-            if (expanded) ...[
-              Positioned(
-                left: 4,
-                top: 0,
-                bottom: 0,
-                child: IgnorePointer(
-                  child: Center(
-                    child: UoscBox(formatUoscTime(_at(played), withHours: withHours),
-                        key: const ValueKey('uosc-time'), color: UoscStyle.bar),
-                  ),
-                ),
-              ),
-              Positioned(
-                right: 4,
-                top: 0,
-                bottom: 0,
-                child: IgnorePointer(
-                  child: Center(
-                    child: UoscBox(formatUoscTime(widget.duration, withHours: withHours),
-                        key: const ValueKey('uosc-duration'), color: UoscStyle.bar),
-                  ),
-                ),
-              ),
-            ],
-            if (hoverAt != null)
-              Positioned(
-                // Kept clear of the window edges (the tip is centred).
-                left: hoverX!.clamp(math.min(60.0, width / 2), math.max(width - 60, width / 2)),
-                bottom: h + 8,
-                child: IgnorePointer(
-                  child: FractionalTranslation(
-                    translation: const Offset(-0.5, 0),
-                    child: Column(
-                      mainAxisSize: MainAxisSize.min,
-                      spacing: 4,
-                      children: [
-                        if (hoverTitle.isNotEmpty) UoscBox(hoverTitle, key: const ValueKey('uosc-hover-chapter')),
-                        UoscBox(formatUoscTime(hoverAt, withHours: withHours),
-                            key: const ValueKey('uosc-hover-time')),
-                      ],
-                    ),
-                  ),
-                ),
-              ),
-          ],
-        ),
-      );
-      if (!expanded) return IgnorePointer(child: bar);
-      return MouseRegion(
-        cursor: SystemMouseCursors.click,
-        onEnter: (e) => setState(() => _hoverX = e.localPosition.dx.clamp(0, width)),
-        onHover: (e) => setState(() => _hoverX = e.localPosition.dx.clamp(0, width)),
-        onExit: (_) => setState(() => _hoverX = null),
-        child: Listener(
-          behavior: HitTestBehavior.opaque,
-          onPointerDown: (e) {
-            _dragFraction = width <= 0 ? 0 : (e.localPosition.dx / width).clamp(0.0, 1.0);
-            _drag(true);
-          },
-          onPointerMove: (e) {
-            setState(() => _hoverX = e.localPosition.dx.clamp(0, width));
-            _seekTo(e.localPosition.dx, width);
-          },
-          onPointerUp: (e) {
-            _seekTo(e.localPosition.dx, width);
-            _drag(false);
-          },
-          onPointerCancel: (_) => _drag(false),
-          child: bar,
-        ),
-      );
-    });
+        ],
+      ),
+    );
+    if (!expanded) return IgnorePointer(child: bar);
+    Offset clampTo(Offset p) => Offset(p.dx.clamp(0.0, width), p.dy);
+    return MouseRegion(
+      cursor: SystemMouseCursors.click,
+      onEnter: (e) => setState(() => _hover = clampTo(e.localPosition)),
+      onHover: (e) => setState(() => _hover = clampTo(e.localPosition)),
+      onExit: (_) {
+        if (!_dragging) setState(() => _hover = null);
+      },
+      child: Listener(
+        behavior: HitTestBehavior.opaque,
+        onPointerDown: (e) {
+          if (duration <= Duration.zero || width <= 0) return;
+          final at = clampTo(e.localPosition);
+          final chapter = _hoveredChapter(geo, marks, at);
+          _lastSent = null;
+          if (chapter != null) {
+            final f = timelineFraction(marks[chapter].start, duration);
+            _settle(f);
+            _send(marks[chapter].start);
+            setState(() {});
+            return;
+          }
+          _pending = null;
+          _dragFraction = geo.fractionAt(at.dx);
+          _drag(true);
+          _send(_at(_dragFraction));
+        },
+        onPointerMove: (e) {
+          if (!_dragging) return;
+          final at = clampTo(e.localPosition);
+          setState(() {
+            _hover = at;
+            _dragFraction = geo.fractionAt(at.dx);
+          });
+          _send(_at(_dragFraction));
+        },
+        onPointerUp: (e) {
+          if (!_dragging) return;
+          _send(_at(_dragFraction));
+          _settle(_dragFraction);
+          final p = e.localPosition;
+          if (p.dx < 0 || p.dx > width || p.dy < 0 || p.dy > geo.height) _hover = null;
+          _drag(false);
+        },
+        onPointerCancel: (_) => _drag(false),
+        child: bar,
+      ),
+    );
   }
+
+  static const _tipStyle = TextStyle(color: UoscStyle.text, fontSize: UoscTimelineSpec.fontSize, height: 1);
 }
 
-/// Background, cached range (hatched, or a faint band when collapsed),
-/// the played part and the hover line.
+/// The hover tooltips: the time centred on [x], the chapter title over
+/// it; each kept [UoscTimelineSpec.tooltipGap] inside the band's ends.
+class _TooltipLayout extends MultiChildLayoutDelegate {
+  final double x;
+  _TooltipLayout({required this.x});
+
+  @override
+  void performLayout(Size size) {
+    const gap = UoscTimelineSpec.tooltipGap;
+    double left(double w) => (x - w / 2).clamp(gap, math.max(gap, size.width - gap - w));
+    final loose = BoxConstraints.loose(size);
+    final time = layoutChild(#time, loose);
+    final timeTop = size.height - time.height;
+    positionChild(#time, Offset(left(time.width), timeTop));
+    if (hasChild(#chapter)) {
+      final chapter = layoutChild(#chapter, loose);
+      positionChild(#chapter, Offset(left(chapter.width), timeTop - gap - chapter.height));
+    }
+  }
+
+  @override
+  bool shouldRelayout(_TooltipLayout old) => old.x != x;
+}
+
+/// Paints the band as uosc does: background, the position line, the
+/// uncached hatching, chapter diamonds, the times, the hover line.
 class UoscTimelinePainter extends CustomPainter {
-  final double played;
-  final Rect? Function(Size size) cache;
-  /// What [cache] depends on (repaint when it changes).
-  final Object cacheKey;
+  final UoscTimelineGeometry geometry;
+
+  /// 0 hidden .. 1 shown (picks the hatching texture and its strength).
+  final double visibility;
+
+  /// Start of the uncached part (to the end), as a fraction.
+  final double? uncached;
+
+  /// Chapter starts, as fractions.
+  final List<double> chapters;
+  final int? hoveredChapter;
+
+  /// The hover line (the mouse, or the hovered chapter).
   final double? hoverX;
-  final bool hatched;
+  final double textOpacity;
+  final String? elapsed;
+  final String? remaining;
+  final String? cache;
+  final String? fontFamily;
   const UoscTimelinePainter({
-    required this.played,
-    required this.cache,
-    required this.cacheKey,
+    required this.geometry,
+    this.visibility = 1,
+    this.uncached,
+    this.chapters = const [],
+    this.hoveredChapter,
     this.hoverX,
-    this.hatched = true,
+    this.textOpacity = 1,
+    this.elapsed,
+    this.remaining,
+    this.cache,
+    this.fontFamily,
   });
 
+  double get played => geometry.progress;
+
   @override
   void paint(Canvas canvas, Size size) {
-    final all = Offset.zero & size;
-    canvas.drawRect(all, Paint()..color = UoscStyle.bar);
-    final c = cache(size);
-    if (c != null) {
-      if (hatched) {
-        canvas.save();
-        canvas.clipRect(c);
-        final stroke = Paint()
-          ..color = const Color(0x40FFFFFF)
-          ..strokeWidth = 1.5;
-        for (final (a, b) in hatchLines(c)) {
-          canvas.drawLine(a, b, stroke);
-        }
-        canvas.restore();
-      } else {
-        canvas.drawRect(c, Paint()..color = const Color(0x40FFFFFF));
-      }
-    }
-    canvas.drawRect(Rect.fromLTWH(0, 0, size.width * played, size.height), Paint()..color = UoscStyle.fill);
+    final g = geometry;
+    final w = size.width, bottom = size.height, top = g.top;
+    final line = Rect.fromLTRB(g.lineLeft, top, g.lineRight, bottom);
+    // Background (`opacity.timeline`) around the position line.
+    final bg = Path()
+      ..fillType = PathFillType.evenOdd
+      ..addRect(Offset.zero & size)
+      ..addRect(line);
+    canvas.drawPath(bg, Paint()..color = Colors.black.withValues(alpha: UoscTimelineSpec.opacity));
+    canvas.drawRect(line, Paint()..color = Colors.white);
+    _hatch(canvas, w, top, bottom);
+    _chapters(canvas);
+    if (textOpacity > 0) _times(canvas, w, top, bottom, line);
     final x = hoverX;
     if (x != null) {
-      canvas.drawRect(Rect.fromLTWH(x - 0.5, 0, 1, size.height), Paint()..color = Colors.white70);
+      final onLine = line.left - 0.5 < x && x < line.right + 0.5;
+      canvas.drawRect(
+        Rect.fromLTRB(x - 0.5, top, x + 0.5, bottom),
+        Paint()..color = (onLine ? Colors.black : Colors.white).withValues(alpha: 0.33),
+      );
     }
   }
 
+  /// uosc's texture "b" (shown) or "a" (hidden) at 80 px: "/" stripes
+  /// 1.6 px thick, white then black shifted by size / 24 (or / 28).
+  void _hatch(Canvas canvas, double w, double top, double bottom) {
+    final from = uncached;
+    if (from == null) return;
+    final ax = from * (geometry.width) < 0.5 ? 0.0 : geometry.x(from).floorToDouble();
+    if (ax >= w) return;
+    final shown = visibility > 0;
+    const tile = 80.0, unit = tile / 100;
+    final period = (shown ? 100 / 12 : 100 / 14) * unit;
+    final phase = shown ? 0.0 : 5.727 * unit;
+    final offset = tile / (shown ? 24 : 28);
+    final h = bottom - top;
+    canvas.save();
+    canvas.clipRect(Rect.fromLTRB(ax, top, w, bottom));
+    void stripes(Color color, double opacity, double anchor) {
+      final paint = Paint()
+        ..color = color.withValues(alpha: opacity)
+        ..strokeWidth = 2 * unit;
+      // x + (y - bottom) = anchor + phase + k * period.
+      final base = anchor + phase;
+      final k0 = ((ax - h - base) / period).floor() - 1;
+      for (var k = k0; base + k * period <= w + 1; k++) {
+        final c = base + k * period;
+        canvas.drawLine(Offset(c, bottom), Offset(c + h, top), paint);
+      }
+    }
+
+    stripes(Colors.white, 0.4 - 0.2 * visibility, 0);
+    stripes(Colors.black, 0.6 - 0.2 * visibility, offset);
+    canvas.restore();
+  }
+
+  void _chapters(Canvas canvas) {
+    final g = geometry;
+    final r = g.diamondRadius;
+    if (r <= 0) return;
+    void diamond(double fraction, double radius) {
+      final c = Offset(g.x(fraction), 0);
+      Path shape(double r) => Path()
+        ..moveTo(c.dx - r, c.dy)
+        ..lineTo(c.dx, c.dy - r)
+        ..lineTo(c.dx + r, c.dy)
+        ..lineTo(c.dx, c.dy + r)
+        ..close();
+      final inner = shape(radius);
+      // A 1 px border outside the fill (`\bord`), the fill translucent.
+      final outer = shape(radius + UoscTimelineSpec.border * math.sqrt2);
+      canvas.drawPath(Path.combine(PathOperation.difference, outer, inner), Paint()..color = Colors.black);
+      canvas.drawPath(inner, Paint()..color = Colors.white.withValues(alpha: UoscTimelineSpec.chaptersOpacity));
+    }
+
+    for (var i = 0; i < chapters.length; i++) {
+      if (i != hoveredChapter) diamond(chapters[i], r);
+    }
+    final h = hoveredChapter;
+    if (h != null && h < chapters.length) diamond(chapters[h], r * 2);
+  }
+
+  TextPainter _text(String s, double fontSize, Color color, {Paint? foreground}) => TextPainter(
+    text: TextSpan(
+      text: s,
+      style: TextStyle(
+        fontFamily: fontFamily,
+        fontSize: fontSize,
+        height: 1,
+        color: foreground == null ? color : null,
+        foreground: foreground,
+        fontFeatures: const [FontFeature.tabularFigures()],
+      ),
+    ),
+    textDirection: TextDirection.ltr,
+  )..layout();
+
+  /// Text on the band: white with a black outline, inverted where it
+  /// crosses the position line (uosc clips one copy to each).
+  void _label(Canvas canvas, String s, double fontSize, double opacity, Offset at, Rect line, Size size) {
+    void copy(Color fill, Color outline) {
+      _text(
+        s,
+        fontSize,
+        fill,
+        foreground: Paint()
+          ..style = PaintingStyle.stroke
+          ..strokeWidth = UoscTimelineSpec.textBorder * 2
+          ..strokeJoin = StrokeJoin.round
+          ..color = outline.withValues(alpha: opacity),
+      ).paint(canvas, at);
+      _text(s, fontSize, fill.withValues(alpha: opacity)).paint(canvas, at);
+    }
+
+    canvas.save();
+    canvas.clipPath(
+      Path()
+        ..fillType = PathFillType.evenOdd
+        ..addRect(Rect.fromLTWH(-20, -20, size.width + 40, size.height + 40))
+        ..addRect(line),
+    );
+    copy(Colors.white, Colors.black);
+    canvas.restore();
+    canvas.save();
+    canvas.clipRect(line);
+    copy(Colors.black, Colors.white);
+    canvas.restore();
+  }
+
+  void _times(Canvas canvas, double w, double top, double bottom, Rect line) {
+    const fs = UoscTimelineSpec.fontSize, spacing = UoscTimelineSpec.spacing;
+    final size = Size(w, bottom);
+    final cy = top + (bottom - top) / 2;
+    final e = elapsed, r = remaining;
+    final ew = e == null ? 0.0 : _text(e, fs, Colors.white).width;
+    final rw = r == null ? 0.0 : _text(r, fs, Colors.white).width;
+    final c = cache;
+    if (c != null) {
+      const cfs = fs * 0.8, margin = 5.0;
+      final cw = _text(c, cfs, Colors.white).width;
+      var x = line.right + margin;
+      final minX = spacing + margin + ew, maxX = w - spacing - margin - rw;
+      if (x < minX) {
+        x = minX;
+      } else if (x + cw > maxX) {
+        x = maxX - cw;
+      }
+      _label(canvas, c, cfs, textOpacity * 0.6, Offset(x, cy - cfs / 2), line, size);
+    }
+    if (e != null) _label(canvas, e, fs, textOpacity, Offset(spacing, cy - fs / 2), line, size);
+    if (r != null) _label(canvas, r, fs, textOpacity, Offset(w - spacing - rw, cy - fs / 2), line, size);
+  }
+
   @override
-  bool shouldRepaint(UoscTimelinePainter old) =>
-      old.played != played || old.cacheKey != cacheKey || old.hoverX != hoverX || old.hatched != hatched;
+  bool shouldRepaint(UoscTimelinePainter old) => true;
 }

apps/desktop/lib/src/controls/uosc/volume_flash.dart

@@ -0,0 +1,128 @@
+import 'dart:math' as math;
+
+import 'package:flutter/material.dart';
+
+import '../volume.dart' show maxVolume;
+
+// uosc's volume slider (`elements/Volume.lua`) as it flashes on a volume
+// change: a vertical band at the right edge, black at `opacity.slider`
+// with a white gauge from the bottom, notches at 100 %, the value at the
+// bottom (black on the gauge, white off it).
+
+/// The flashed uosc volume slider; size it with [UoscVolumeSlider.width]
+/// and the height uosc gives it (see [UoscVolumeSlider.heightFor]).
+class UoscVolumeSlider extends StatelessWidget {
+  /// 0..[maxVolume].
+  final double volume;
+  const UoscVolumeSlider({super.key, required this.volume});
+
+  /// `volume_size`.
+  static const width = 40.0;
+
+  /// uosc: min(size * 8, 80 % of the room between the bars), less the
+  /// mute button (one [width]) below it.
+  static double heightFor(double room) => math.min(width * 8, room * 0.8) - width;
+
+  @override
+  Widget build(BuildContext context) => CustomPaint(
+    key: const ValueKey('uosc-volume-flash'),
+    painter: UoscVolumePainter(
+      volume: volume,
+      fontFamily: DefaultTextStyle.of(context).style.fontFamily ?? Theme.of(context).textTheme.bodyMedium?.fontFamily,
+    ),
+  );
+}
+
+class UoscVolumePainter extends CustomPainter {
+  final double volume;
+  final String? fontFamily;
+  const UoscVolumePainter({required this.volume, this.fontFamily});
+
+  /// `volume_border`, `border_radius`.
+  static const border = 1.0;
+  static const radius = 4.0;
+
+  @override
+  void paint(Canvas canvas, Size size) {
+    final w = size.width, h = size.height;
+    if (w <= 0 || h <= w) return;
+    final v = volume.clamp(0.0, maxVolume);
+    final nudgeY = h - (h * (100 / maxVolume)).roundToDouble();
+    final nudge = (w * 0.18).roundToDouble();
+    final spacing = (w * 0.2).roundToDouble();
+    Path notches(double inset) {
+      final n = nudge - inset;
+      return Path()
+        ..moveTo(0, nudgeY - nudge)
+        ..lineTo(inset + n, nudgeY)
+        ..lineTo(0, nudgeY + nudge)
+        ..close()
+        ..moveTo(w, nudgeY - nudge)
+        ..lineTo(w - inset - n, nudgeY)
+        ..lineTo(w, nudgeY + nudge)
+        ..close();
+    }
+
+    final bg = RRect.fromRectAndRadius(Offset.zero & size, const Radius.circular(radius + border));
+    final volumeY = border + (h - border * 2) * (1 - math.min(v / maxVolume, 1));
+    final gauge = RRect.fromRectAndRadius(
+      Rect.fromLTRB(border, math.min(volumeY, h - border), w - border, h - border),
+      const Radius.circular(radius),
+    );
+    // The notches cut into both.
+    canvas.save();
+    canvas.clipPath(
+      Path()
+        ..fillType = PathFillType.evenOdd
+        ..addRect(Offset.zero & size)
+        ..addPath(notches(0), Offset.zero),
+    );
+    canvas.drawPath(
+      Path()
+        ..fillType = PathFillType.evenOdd
+        ..addRRect(bg)
+        ..addRRect(gauge),
+      Paint()..color = Colors.black.withValues(alpha: 0.9),
+    );
+    canvas.restore();
+    canvas.save();
+    canvas.clipPath(
+      Path()
+        ..fillType = PathFillType.evenOdd
+        ..addRect(Offset.zero & size)
+        ..addPath(notches(border), Offset.zero),
+    );
+    canvas.drawRRect(gauge, Paint()..color = Colors.white);
+    canvas.restore();
+
+    // round(volume * 10) / 10, as Lua prints it ("85", "85.5").
+    final tenths = (v * 10).round();
+    final text = tenths % 10 == 0 ? '${tenths ~/ 10}' : (tenths / 10).toString();
+    final fontSize = (w * 0.6 - text.length * (w / 20)).roundToDouble();
+    TextPainter label(Color color) => TextPainter(
+      text: TextSpan(
+        text: text,
+        style: TextStyle(fontFamily: fontFamily, fontSize: fontSize, height: 1, color: color),
+      ),
+      textDirection: TextDirection.ltr,
+    )..layout();
+    final dark = label(Colors.black), light = label(Colors.white);
+    final at = Offset((w - dark.width) / 2, h - spacing - dark.height);
+    canvas.save();
+    canvas.clipRRect(gauge);
+    dark.paint(canvas, at);
+    canvas.restore();
+    canvas.save();
+    canvas.clipPath(
+      Path()
+        ..fillType = PathFillType.evenOdd
+        ..addRect(Offset.zero & size)
+        ..addRRect(gauge),
+    );
+    light.paint(canvas, at);
+    canvas.restore();
+  }
+
+  @override
+  bool shouldRepaint(UoscVolumePainter old) => old.volume != volume || old.fontFamily != fontFamily;
+}