Fair bit of code cleanup.

lib/ui/common/controls/eight_way_swipe_detector.dart

@@ -64,21 +64,23 @@ class _EightWaySwipeDetectorState extends State<EightWaySwipeDetector> {
   @override
   Widget build(BuildContext context) {
     return TrackpadListener(
+      scrollSensitivity: 70,
       onScroll: _trackpadSwipe,
       child: GestureDetector(
-          behavior: HitTestBehavior.translucent,
-          onPanStart: _handleSwipeStart,
-          onPanUpdate: _handleSwipeUpdate,
-          onPanCancel: _resetSwipe,
-          onPanEnd: _handleSwipeEnd,
-          supportedDevices: const {
-            // Purposely omitting PointerDeviceKind.trackpad.
-            PointerDeviceKind.mouse,
-            PointerDeviceKind.stylus,
-            PointerDeviceKind.touch,
-            PointerDeviceKind.unknown,
-          },
-          child: widget.child),
+        behavior: HitTestBehavior.translucent,
+        onPanStart: _handleSwipeStart,
+        onPanUpdate: _handleSwipeUpdate,
+        onPanCancel: _resetSwipe,
+        onPanEnd: _handleSwipeEnd,
+        supportedDevices: const {
+          // Purposely omitting PointerDeviceKind.trackpad.
+          PointerDeviceKind.mouse,
+          PointerDeviceKind.stylus,
+          PointerDeviceKind.touch,
+          PointerDeviceKind.unknown,
+        },
+        child: widget.child,
+      ),
     );
   }
 }

lib/ui/common/controls/trackpad_listener.dart

@@ -6,20 +6,12 @@ import 'package:wonders/common_libs.dart';
 class TrackpadListener extends StatefulWidget {
   final Widget child;
   final double scrollSensitivity;
-  final void Function()? onScrollUp;
-  final void Function()? onScrollDown;
-  final void Function()? onScrollLeft;
-  final void Function()? onScrollRight;
   final void Function(Offset delta)? onScroll;
 
   const TrackpadListener({
     super.key,
     required this.child,
     this.scrollSensitivity = 100,
-    this.onScrollUp,
-    this.onScrollDown,
-    this.onScrollLeft,
-    this.onScrollRight,
     this.onScroll,
   });
 
@@ -29,48 +21,46 @@ class TrackpadListener extends StatefulWidget {
 
 class _TrackpadListenerState extends State<TrackpadListener> {
   Offset _scrollOffset = Offset.zero;
+
   void _handleTrackpadEvent(PointerSignalEvent event) {
     GestureBinding.instance.pointerSignalResolver.register(event, (PointerSignalEvent event) {
+      // Only handle trackpad events here.
       if (event is PointerScrollEvent && event.kind == PointerDeviceKind.trackpad) {
         Offset newScroll = _scrollOffset + event.scrollDelta;
         newScroll = Offset(
           newScroll.dx.clamp(-widget.scrollSensitivity, widget.scrollSensitivity),
           newScroll.dy.clamp(-widget.scrollSensitivity, widget.scrollSensitivity),
         );
-        _update(newScroll);
+        _scrollOffset = newScroll;
+        _update();
       }
     });
   }
 
-  void _update(Offset newOffset) {
+  void _update() {
     Offset directionScroll = Offset.zero;
     double sensitivity = widget.scrollSensitivity;
-    while (newOffset.dy >= sensitivity) {
-      widget.onScrollDown?.call();
-      newOffset -= Offset(0.0, sensitivity);
-      directionScroll -= Offset(0.0, 1.0);
-    }
-    while (newOffset.dy <= -sensitivity) {
-      widget.onScrollUp?.call();
-      newOffset += Offset(0.0, sensitivity);
+    if (_scrollOffset.dy >= sensitivity) {
+      // Scroll down
+      _scrollOffset += Offset(0.0, -sensitivity);
+      directionScroll += Offset(0.0, -1.0);
+    } else if (_scrollOffset.dy <= -sensitivity) {
+      // Scroll up
+      _scrollOffset += Offset(0.0, sensitivity);
       directionScroll += Offset(0.0, 1.0);
     }
-    while (newOffset.dx >= sensitivity) {
-      widget.onScrollLeft?.call();
-      newOffset -= Offset(sensitivity, 0.0);
-      directionScroll -= Offset(1.0, 0.0);
-    }
-    while (newOffset.dx <= -sensitivity) {
-      widget.onScrollRight?.call();
-      newOffset += Offset(sensitivity, 0.0);
+    if (_scrollOffset.dx >= sensitivity) {
+      // Scroll left
+      _scrollOffset += Offset(-sensitivity, 0.0);
+      directionScroll += Offset(-1.0, 0.0);
+    } else if (_scrollOffset.dx <= -sensitivity) {
+      // Scroll right
+      _scrollOffset += Offset(sensitivity, 0.0);
       directionScroll += Offset(1.0, 0.0);
     }
     if (directionScroll != Offset.zero) {
       widget.onScroll?.call(directionScroll);
     }
-    // Tone it down over time.
-    newOffset *= 0.9;
-    setState(() => _scrollOffset = newOffset);
   }
 
   @override

lib/ui/screens/editorial/editorial_screen.dart

@@ -65,9 +65,9 @@ class _WonderEditorialScreenState extends State<WonderEditorialScreen> {
     _scrollPos.value = _scroller.position.pixels;
   }
 
-  void _handleSwipeUp() {
+  void _handleTrackpadScroll(Offset direction) {
     // Trackpad swipe up. Return to home if at the top.
-    if (_scroller.position.pixels == 0) {
+    if (_scroller.position.pixels == 0 && direction.dy > 0) {
       _handleBackPressed();
     }
   }
@@ -89,7 +89,7 @@ class _WonderEditorialScreenState extends State<WonderEditorialScreen> {
         child: ColoredBox(
           color: $styles.colors.offWhite,
           child: TrackpadListener(
-            onScrollUp: _handleSwipeUp,
+            onScroll: _handleTrackpadScroll,
             scrollSensitivity: 120,
             child: Stack(
               children: [

lib/ui/screens/home/wonders_home_screen.dart

@@ -132,6 +132,12 @@ class _HomeScreenState extends State<HomeScreen> with SingleTickerProviderStateM
     }
   }
 
+  void _handleTrackpadScroll(Offset direction) {
+    if (direction.dy < 0) {
+      _showDetailsPage();
+    }
+  }
+
   @override
   Widget build(BuildContext context) {
     if (_fadeInOnNextBuild == true) {
@@ -143,7 +149,7 @@ class _HomeScreenState extends State<HomeScreen> with SingleTickerProviderStateM
       color: $styles.colors.black,
       child: TrackpadListener(
         scrollSensitivity: 60,
-        onScrollDown: () => _showDetailsPage(),
+        onScroll: _handleTrackpadScroll,
         child: PreviousNextNavigation(
           listenToMouseWheel: false,
           onPreviousPressed: () => _handlePrevNext(-1),