Implementing `switch` expressions in `widgets/` (#143293)

This PR is the 7ᵗʰ step in the journey to solve issue #136139 and make the entire Flutter repo more readable.

(previous pull requests: #139048, #139882, #141591, #142279, #142634, #142793)

This pull request covers everything in `packages/flutter/lib/src/widgets/`. Most of it should be really straightforward, but there was some refactoring in the `getOffsetToReveal()` function in `two_dimensional_viewport.dart`. I'll add some comments to describe those changes.

packages/flutter/lib/src/widgets/actions.dart

@@ -1244,12 +1244,10 @@ class _FocusableActionDetectorState extends State<FocusableActionDetector> {
   bool _canShowHighlight = false;
   void _updateHighlightMode(FocusHighlightMode mode) {
     _mayTriggerCallback(task: () {
-      switch (FocusManager.instance.highlightMode) {
-        case FocusHighlightMode.touch:
-          _canShowHighlight = false;
-        case FocusHighlightMode.traditional:
-          _canShowHighlight = true;
-      }
+      _canShowHighlight = switch (FocusManager.instance.highlightMode) {
+        FocusHighlightMode.touch       => false,
+        FocusHighlightMode.traditional => true,
+      };
     });
   }
 
@@ -1303,13 +1301,10 @@ class _FocusableActionDetectorState extends State<FocusableActionDetector> {
     }
 
     bool canRequestFocus(FocusableActionDetector target) {
-      final NavigationMode mode = MediaQuery.maybeNavigationModeOf(context) ?? NavigationMode.traditional;
-      switch (mode) {
-        case NavigationMode.traditional:
-          return target.enabled;
-        case NavigationMode.directional:
-          return true;
-      }
+      return switch (MediaQuery.maybeNavigationModeOf(context)) {
+        NavigationMode.traditional || null => target.enabled,
+        NavigationMode.directional => true,
+      };
     }
 
     bool shouldShowFocusHighlight(FocusableActionDetector target) {
@@ -1344,13 +1339,10 @@ class _FocusableActionDetectorState extends State<FocusableActionDetector> {
   }
 
   bool get _canRequestFocus {
-    final NavigationMode mode = MediaQuery.maybeNavigationModeOf(context) ?? NavigationMode.traditional;
-    switch (mode) {
-      case NavigationMode.traditional:
-        return widget.enabled;
-      case NavigationMode.directional:
-        return true;
-    }
+    return switch (MediaQuery.maybeNavigationModeOf(context)) {
+      NavigationMode.traditional || null => widget.enabled,
+      NavigationMode.directional => true,
+    };
   }
 
   // This global key is needed to keep only the necessary widgets in the tree

packages/flutter/lib/src/widgets/banner.dart

@@ -178,64 +178,32 @@ class BannerPainter extends CustomPainter {
   bool hitTest(Offset position) => false;
 
   double _translationX(double width) {
-    switch (layoutDirection) {
-      case TextDirection.rtl:
-        switch (location) {
-          case BannerLocation.bottomEnd:
-            return _kBottomOffset;
-          case BannerLocation.topEnd:
-            return 0.0;
-          case BannerLocation.bottomStart:
-            return width - _kBottomOffset;
-          case BannerLocation.topStart:
-            return width;
-        }
-      case TextDirection.ltr:
-        switch (location) {
-          case BannerLocation.bottomEnd:
-            return width - _kBottomOffset;
-          case BannerLocation.topEnd:
-            return width;
-          case BannerLocation.bottomStart:
-            return _kBottomOffset;
-          case BannerLocation.topStart:
-            return 0.0;
-        }
-    }
+    return switch ((layoutDirection, location)) {
+      (TextDirection.rtl, BannerLocation.topStart)    => width,
+      (TextDirection.ltr, BannerLocation.topStart)    => 0.0,
+      (TextDirection.rtl, BannerLocation.topEnd)      => 0.0,
+      (TextDirection.ltr, BannerLocation.topEnd)      => width,
+      (TextDirection.rtl, BannerLocation.bottomStart) => width - _kBottomOffset,
+      (TextDirection.ltr, BannerLocation.bottomStart) => _kBottomOffset,
+      (TextDirection.rtl, BannerLocation.bottomEnd)   => _kBottomOffset,
+      (TextDirection.ltr, BannerLocation.bottomEnd)   => width - _kBottomOffset,
+    };
   }
 
   double _translationY(double height) {
-    switch (location) {
-      case BannerLocation.bottomStart:
-      case BannerLocation.bottomEnd:
-        return height - _kBottomOffset;
-      case BannerLocation.topStart:
-      case BannerLocation.topEnd:
-        return 0.0;
-    }
+    return switch (location) {
+      BannerLocation.bottomStart || BannerLocation.bottomEnd => height - _kBottomOffset,
+      BannerLocation.topStart    || BannerLocation.topEnd    => 0.0,
+    };
   }
 
   double get _rotation {
-    switch (layoutDirection) {
-      case TextDirection.rtl:
-        switch (location) {
-          case BannerLocation.bottomStart:
-          case BannerLocation.topEnd:
-            return -math.pi / 4.0;
-          case BannerLocation.bottomEnd:
-          case BannerLocation.topStart:
-            return math.pi / 4.0;
-        }
-      case TextDirection.ltr:
-        switch (location) {
-          case BannerLocation.bottomStart:
-          case BannerLocation.topEnd:
-            return math.pi / 4.0;
-          case BannerLocation.bottomEnd:
-          case BannerLocation.topStart:
-            return -math.pi / 4.0;
-        }
-    }
+    return math.pi / 4.0 * switch ((layoutDirection, location)) {
+      (TextDirection.rtl, BannerLocation.topStart || BannerLocation.bottomEnd) => 1,
+      (TextDirection.ltr, BannerLocation.topStart || BannerLocation.bottomEnd) => -1,
+      (TextDirection.rtl, BannerLocation.bottomStart || BannerLocation.topEnd) => -1,
+      (TextDirection.ltr, BannerLocation.bottomStart || BannerLocation.topEnd) => 1,
+    };
   }
 }
 

packages/flutter/lib/src/widgets/basic.dart

@@ -2813,16 +2813,11 @@ class UnconstrainedBox extends StatelessWidget {
   final Widget? child;
 
   BoxConstraintsTransform _axisToTransform(Axis? constrainedAxis) {
-    if (constrainedAxis != null) {
-      switch (constrainedAxis) {
-        case Axis.horizontal:
-          return ConstraintsTransformBox.heightUnconstrained;
-        case Axis.vertical:
-          return ConstraintsTransformBox.widthUnconstrained;
-      }
-    } else {
-      return ConstraintsTransformBox.unconstrained;
-    }
+    return switch (constrainedAxis) {
+      Axis.horizontal => ConstraintsTransformBox.heightUnconstrained,
+      Axis.vertical   => ConstraintsTransformBox.widthUnconstrained,
+      null            => ConstraintsTransformBox.unconstrained,
+    };
   }
 
   @override
@@ -4263,16 +4258,10 @@ class Positioned extends ParentDataWidget<StackParentData> {
     double? height,
     required Widget child,
   }) {
-    double? left;
-    double? right;
-    switch (textDirection) {
-      case TextDirection.rtl:
-        left = end;
-        right = start;
-      case TextDirection.ltr:
-        left = start;
-        right = end;
-    }
+    final (double? left, double? right) = switch (textDirection) {
+      TextDirection.rtl => (end, start),
+      TextDirection.ltr => (start, end),
+    };
     return Positioned(
       key: key,
       left: left,

packages/flutter/lib/src/widgets/binding.dart

@@ -785,15 +785,12 @@ mixin WidgetsBinding on BindingBase, ServicesBinding, SchedulerBinding, GestureB
   }
 
   Future<dynamic> _handleNavigationInvocation(MethodCall methodCall) {
-    switch (methodCall.method) {
-      case 'popRoute':
-        return handlePopRoute();
-      case 'pushRoute':
-        return handlePushRoute(methodCall.arguments as String);
-      case 'pushRouteInformation':
-        return _handlePushRouteInformation(methodCall.arguments as Map<dynamic, dynamic>);
-    }
-    return Future<dynamic>.value();
+    return switch (methodCall.method) {
+      'popRoute' => handlePopRoute(),
+      'pushRoute' => handlePushRoute(methodCall.arguments as String),
+      'pushRouteInformation' => _handlePushRouteInformation(methodCall.arguments as Map<dynamic, dynamic>),
+      _ => Future<dynamic>.value(),
+    };
   }
 
   @override

packages/flutter/lib/src/widgets/container.dart

@@ -92,13 +92,10 @@ class DecoratedBox extends SingleChildRenderObjectWidget {
   @override
   void debugFillProperties(DiagnosticPropertiesBuilder properties) {
     super.debugFillProperties(properties);
-    final String label;
-    switch (position) {
-      case DecorationPosition.background:
-        label = 'bg';
-      case DecorationPosition.foreground:
-        label = 'fg';
-    }
+    final String label = switch (position) {
+      DecorationPosition.background => 'bg',
+      DecorationPosition.foreground => 'fg',
+    };
     properties.add(EnumProperty<DecorationPosition>('position', position, level: DiagnosticLevel.hidden));
     properties.add(DiagnosticsProperty<Decoration>(label, decoration));
   }

packages/flutter/lib/src/widgets/decorated_sliver.dart

@@ -76,13 +76,10 @@ class DecoratedSliver extends SingleChildRenderObjectWidget {
   @override
   void debugFillProperties(DiagnosticPropertiesBuilder properties) {
     super.debugFillProperties(properties);
-    final String label;
-    switch (position) {
-      case DecorationPosition.background:
-        label = 'bg';
-      case DecorationPosition.foreground:
-        label = 'fg';
-    }
+    final String label = switch (position) {
+      DecorationPosition.background => 'bg',
+      DecorationPosition.foreground => 'fg',
+    };
     properties.add(EnumProperty<DecorationPosition>('position', position, level: DiagnosticLevel.hidden));
     properties.add(DiagnosticsProperty<Decoration>(label, decoration));
   }

packages/flutter/lib/src/widgets/default_text_editing_shortcuts.dart

@@ -472,20 +472,14 @@ class DefaultTextEditingShortcuts extends StatelessWidget {
   };
 
   static Map<ShortcutActivator, Intent> get _shortcuts {
-    switch (defaultTargetPlatform) {
-      case TargetPlatform.android:
-        return _androidShortcuts;
-      case TargetPlatform.fuchsia:
-        return _fuchsiaShortcuts;
-      case TargetPlatform.iOS:
-        return _iOSShortcuts;
-      case TargetPlatform.linux:
-        return _linuxShortcuts;
-      case TargetPlatform.macOS:
-        return _macShortcuts;
-      case TargetPlatform.windows:
-        return _windowsShortcuts;
-    }
+    return switch (defaultTargetPlatform) {
+      TargetPlatform.android => _androidShortcuts,
+      TargetPlatform.fuchsia => _fuchsiaShortcuts,
+      TargetPlatform.iOS     => _iOSShortcuts,
+      TargetPlatform.linux   => _linuxShortcuts,
+      TargetPlatform.macOS   => _macShortcuts,
+      TargetPlatform.windows => _windowsShortcuts,
+    };
   }
 
   Map<ShortcutActivator, Intent>? _getDisablingShortcut() {

packages/flutter/lib/src/widgets/dismissible.dart

@@ -341,12 +341,11 @@ class _DismissibleState extends State<Dismissible> with TickerProviderStateMixin
       return DismissDirection.none;
     }
     if (_directionIsXAxis) {
-      switch (Directionality.of(context)) {
-        case TextDirection.rtl:
-          return extent < 0 ? DismissDirection.startToEnd : DismissDirection.endToStart;
-        case TextDirection.ltr:
-          return extent > 0 ? DismissDirection.startToEnd : DismissDirection.endToStart;
-      }
+      return switch (Directionality.of(context)) {
+        TextDirection.rtl when extent < 0 => DismissDirection.startToEnd,
+        TextDirection.ltr when extent > 0 => DismissDirection.startToEnd,
+        TextDirection.rtl || TextDirection.ltr => DismissDirection.endToStart,
+      };
     }
     return extent > 0 ? DismissDirection.down : DismissDirection.up;
   }

packages/flutter/lib/src/widgets/display_feature_sub_screen.dart

@@ -114,13 +114,10 @@ class DisplayFeatureSubScreen extends StatelessWidget {
   }
 
   static Offset _fallbackAnchorPoint(BuildContext context) {
-    final TextDirection textDirection = Directionality.of(context);
-    switch (textDirection) {
-      case TextDirection.rtl:
-        return const Offset(double.maxFinite, 0);
-      case TextDirection.ltr:
-        return Offset.zero;
-    }
+    return switch (Directionality.of(context)) {
+      TextDirection.rtl => const Offset(double.maxFinite, 0),
+      TextDirection.ltr => Offset.zero,
+    };
   }
 
   /// Returns the areas of the screen that are obstructed by display features.

packages/flutter/lib/src/widgets/navigation_toolbar.dart

@@ -109,26 +109,20 @@ class _ToolbarLayout extends MultiChildLayoutDelegate {
         maxHeight: size.height,
       );
       leadingWidth = layoutChild(_ToolbarSlot.leading, constraints).width;
-      final double leadingX;
-      switch (textDirection) {
-        case TextDirection.rtl:
-          leadingX = size.width - leadingWidth;
-        case TextDirection.ltr:
-          leadingX = 0.0;
-      }
+      final double leadingX = switch (textDirection) {
+        TextDirection.rtl => size.width - leadingWidth,
+        TextDirection.ltr => 0.0,
+      };
       positionChild(_ToolbarSlot.leading, Offset(leadingX, 0.0));
     }
 
     if (hasChild(_ToolbarSlot.trailing)) {
       final BoxConstraints constraints = BoxConstraints.loose(size);
       final Size trailingSize = layoutChild(_ToolbarSlot.trailing, constraints);
-      final double trailingX;
-      switch (textDirection) {
-        case TextDirection.rtl:
-          trailingX = 0.0;
-        case TextDirection.ltr:
-          trailingX = size.width - trailingSize.width;
-      }
+      final double trailingX = switch (textDirection) {
+        TextDirection.rtl => 0.0,
+        TextDirection.ltr => size.width - trailingSize.width,
+      };
       final double trailingY = (size.height - trailingSize.height) / 2.0;
       trailingWidth = trailingSize.width;
       positionChild(_ToolbarSlot.trailing, Offset(trailingX, trailingY));
@@ -153,13 +147,10 @@ class _ToolbarLayout extends MultiChildLayoutDelegate {
         }
       }
 
-      final double middleX;
-      switch (textDirection) {
-        case TextDirection.rtl:
-          middleX = size.width - middleSize.width - middleStart;
-        case TextDirection.ltr:
-          middleX = middleStart;
-      }
+      final double middleX = switch (textDirection) {
+        TextDirection.rtl => size.width - middleSize.width - middleStart,
+        TextDirection.ltr => middleStart,
+      };
 
       positionChild(_ToolbarSlot.middle, Offset(middleX, middleY));
     }

packages/flutter/lib/src/widgets/nested_scroll_view.dart

@@ -1686,17 +1686,11 @@ class SliverOverlapAbsorberHandle extends ChangeNotifier {
 
   @override
   String toString() {
-    String? extra;
-    switch (_writers) {
-      case 0:
-        extra = ', orphan';
-      case 1:
-        // normal case
-        break;
-      default:
-        extra = ', $_writers WRITERS ASSIGNED';
-        break;
-    }
+    final String? extra = switch (_writers) {
+      0 => ', orphan',
+      1 => null, // normal case
+      _ => ', $_writers WRITERS ASSIGNED',
+    };
     return '${objectRuntimeType(this, 'SliverOverlapAbsorberHandle')}($layoutExtent$extra)';
   }
 }

packages/flutter/lib/src/widgets/overflow_bar.dart

@@ -467,15 +467,11 @@ class _RenderOverflowBar extends RenderBox
       double y = 0;
       while (child != null) {
         final _OverflowBarParentData childParentData = child.parentData! as _OverflowBarParentData;
-        double x = 0;
-        switch (overflowAlignment) {
-          case OverflowBarAlignment.start:
-            x = rtl ? constraints.maxWidth - child.size.width : 0;
-          case OverflowBarAlignment.center:
-            x = (constraints.maxWidth - child.size.width) / 2;
-          case OverflowBarAlignment.end:
-            x = rtl ? 0 : constraints.maxWidth - child.size.width;
-        }
+        final double x = switch (overflowAlignment) {
+          OverflowBarAlignment.center => (constraints.maxWidth - child.size.width) / 2,
+          OverflowBarAlignment.start  => rtl ? constraints.maxWidth - child.size.width : 0,
+          OverflowBarAlignment.end    => rtl ? 0 : constraints.maxWidth - child.size.width,
+        };
         childParentData.offset = Offset(x, y);
         y += child.size.height + overflowSpacing;
         child = nextChild();

packages/flutter/lib/src/widgets/reorderable_list.dart

@@ -972,12 +972,10 @@ class SliverReorderableListState extends State<SliverReorderableList> with Ticke
 
   Widget _itemBuilder(BuildContext context, int index) {
     if (_dragInfo != null && index >= widget.itemCount) {
-      switch (_scrollDirection) {
-        case Axis.horizontal:
-          return SizedBox(width: _dragInfo!.itemExtent);
-        case Axis.vertical:
-          return SizedBox(height: _dragInfo!.itemExtent);
-      }
+      return switch (_scrollDirection) {
+        Axis.horizontal => SizedBox(width: _dragInfo!.itemExtent),
+        Axis.vertical   => SizedBox(height: _dragInfo!.itemExtent),
+      };
     }
     final Widget child = widget.itemBuilder(context, index);
     assert(child.key != null, 'All list items must have a key');
@@ -1500,39 +1498,31 @@ class _DragItemProxy extends StatelessWidget {
 }
 
 double _sizeExtent(Size size, Axis scrollDirection) {
-  switch (scrollDirection) {
-    case Axis.horizontal:
-      return size.width;
-    case Axis.vertical:
-      return size.height;
-  }
+  return switch (scrollDirection) {
+    Axis.horizontal => size.width,
+    Axis.vertical   => size.height,
+  };
 }
 
 double _offsetExtent(Offset offset, Axis scrollDirection) {
-  switch (scrollDirection) {
-    case Axis.horizontal:
-      return offset.dx;
-    case Axis.vertical:
-      return offset.dy;
-  }
+  return switch (scrollDirection) {
+    Axis.horizontal => offset.dx,
+    Axis.vertical   => offset.dy,
+  };
 }
 
 Offset _extentOffset(double extent, Axis scrollDirection) {
-  switch (scrollDirection) {
-    case Axis.horizontal:
-      return Offset(extent, 0.0);
-    case Axis.vertical:
-      return Offset(0.0, extent);
-  }
+  return switch (scrollDirection) {
+    Axis.horizontal => Offset(extent, 0.0),
+    Axis.vertical   => Offset(0.0, extent),
+  };
 }
 
 Offset _restrictAxis(Offset offset, Axis scrollDirection) {
-  switch (scrollDirection) {
-    case Axis.horizontal:
-      return Offset(offset.dx, 0.0);
-    case Axis.vertical:
-      return Offset(0.0, offset.dy);
-  }
+  return switch (scrollDirection) {
+    Axis.horizontal => Offset(offset.dx, 0.0),
+    Axis.vertical   => Offset(0.0, offset.dy),
+  };
 }
 
 // A global key that takes its identity from the object and uses a value of a

packages/flutter/lib/src/widgets/selectable_region.dart

@@ -461,15 +461,11 @@ class SelectableRegionState extends State<SelectableRegion> with TextSelectionDe
   }
 
   void _updateSelectionStatus() {
-    final TextSelection selection;
     final SelectionGeometry geometry = _selectionDelegate.value;
-    switch (geometry.status) {
-      case SelectionStatus.uncollapsed:
-      case SelectionStatus.collapsed:
-        selection = const TextSelection(baseOffset: 0, extentOffset: 1);
-      case SelectionStatus.none:
-        selection = const TextSelection.collapsed(offset: 1);
-    }
+    final TextSelection selection = switch (geometry.status) {
+      SelectionStatus.uncollapsed || SelectionStatus.collapsed => const TextSelection(baseOffset: 0, extentOffset: 1),
+      SelectionStatus.none => const TextSelection.collapsed(offset: 1),
+    };
     textEditingValue = TextEditingValue(text: '__', selection: selection);
     if (_hasSelectionOverlayGeometry) {
       _updateSelectionOverlay();

packages/flutter/lib/src/widgets/semantics_debugger.dart

@@ -316,12 +316,10 @@ class _SemanticsDebuggerPainter extends CustomPainter {
         effectivelabel = '${Unicode.FSI}$tooltipAndLabel${Unicode.PDI}';
         annotations.insert(0, 'MISSING TEXT DIRECTION');
       } else {
-        switch (data.textDirection!) {
-          case TextDirection.rtl:
-            effectivelabel = '${Unicode.RLI}$tooltipAndLabel${Unicode.PDI}';
-          case TextDirection.ltr:
-            effectivelabel = tooltipAndLabel;
-        }
+        effectivelabel = switch (data.textDirection!) {
+          TextDirection.rtl => '${Unicode.RLI}$tooltipAndLabel${Unicode.PDI}',
+          TextDirection.ltr => tooltipAndLabel,
+        };
       }
       if (annotations.isEmpty) {
         message = effectivelabel;

packages/flutter/lib/src/widgets/sliver.dart

@@ -1063,13 +1063,10 @@ class SliverMultiBoxAdaptorElement extends RenderObjectElement implements Render
   void debugVisitOnstageChildren(ElementVisitor visitor) {
     _childElements.values.cast<Element>().where((Element child) {
       final SliverMultiBoxAdaptorParentData parentData = child.renderObject!.parentData! as SliverMultiBoxAdaptorParentData;
-      final double itemExtent;
-      switch (renderObject.constraints.axis) {
-        case Axis.horizontal:
-          itemExtent = child.renderObject!.paintBounds.width;
-        case Axis.vertical:
-          itemExtent = child.renderObject!.paintBounds.height;
-      }
+      final double itemExtent = switch (renderObject.constraints.axis) {
+        Axis.horizontal => child.renderObject!.paintBounds.width,
+        Axis.vertical   => child.renderObject!.paintBounds.height,
+      };
 
       return parentData.layoutOffset != null &&
           parentData.layoutOffset! < renderObject.constraints.scrollOffset + renderObject.constraints.remainingPaintExtent &&

packages/flutter/lib/src/widgets/text_selection.dart

@@ -913,12 +913,10 @@ class TextSelectionOverlay {
       return TextSelectionHandleType.collapsed;
     }
 
-    switch (textDirection) {
-      case TextDirection.ltr:
-        return ltrType;
-      case TextDirection.rtl:
-        return rtlType;
-    }
+    return switch (textDirection) {
+      TextDirection.ltr => ltrType,
+      TextDirection.rtl => rtlType,
+    };
   }
 }
 

packages/flutter/lib/src/widgets/transitions.dart

@@ -296,19 +296,13 @@ class MatrixTransition extends AnimatedWidget {
     // a saveLayer call. This is usually worthwhile when animating the layer,
     // but leaving it in the layer tree before the animation has started or after
     // it has finished significantly hurts performance.
-    final bool useFilterQuality;
-    switch (animation.status) {
-      case AnimationStatus.dismissed:
-      case AnimationStatus.completed:
-        useFilterQuality = false;
-      case AnimationStatus.forward:
-      case AnimationStatus.reverse:
-        useFilterQuality = true;
-    }
     return Transform(
       transform: onTransform(animation.value),
       alignment: alignment,
-      filterQuality: useFilterQuality ? filterQuality : null,
+      filterQuality: switch (animation.status) {
+        AnimationStatus.forward   || AnimationStatus.reverse   => filterQuality,
+        AnimationStatus.dismissed || AnimationStatus.completed => null,
+      },
       child: child,
     );
   }

packages/flutter/lib/src/widgets/two_dimensional_viewport.dart

@@ -947,31 +947,23 @@ abstract class RenderTwoDimensionalViewport extends RenderBox implements RenderA
     final RenderBox box = child as RenderBox;
     final Rect rectLocal = MatrixUtils.transformRect(target.getTransformTo(child), rect);
 
-    final double targetMainAxisExtent;
     double leadingScrollOffset = offset;
+
     // The scroll offset of `rect` within `child`.
-    switch (axisDirection) {
-      case AxisDirection.up:
-        leadingScrollOffset += child.size.height - rectLocal.bottom;
-        targetMainAxisExtent = rectLocal.height;
-      case AxisDirection.right:
-        leadingScrollOffset += rectLocal.left;
-        targetMainAxisExtent = rectLocal.width;
-      case AxisDirection.down:
-        leadingScrollOffset += rectLocal.top;
-        targetMainAxisExtent = rectLocal.height;
-      case AxisDirection.left:
-        leadingScrollOffset += child.size.width - rectLocal.right;
-        targetMainAxisExtent = rectLocal.width;
-    }
+    leadingScrollOffset += switch (axisDirection) {
+      AxisDirection.up    => child.size.height - rectLocal.bottom,
+      AxisDirection.left  => child.size.width - rectLocal.right,
+      AxisDirection.right => rectLocal.left,
+      AxisDirection.down  => rectLocal.top,
+    };
 
     // The scroll offset in the viewport to `rect`.
-    final TwoDimensionalViewportParentData childParentData = parentDataOf(box);
+    final Offset paintOffset = parentDataOf(box).paintOffset!;
     leadingScrollOffset += switch (axisDirection) {
-      AxisDirection.down => childParentData.paintOffset!.dy,
-      AxisDirection.up => viewportDimension.height - childParentData.paintOffset!.dy - box.size.height,
-      AxisDirection.right => childParentData.paintOffset!.dx,
-      AxisDirection.left => viewportDimension.width - childParentData.paintOffset!.dx - box.size.width,
+      AxisDirection.up    => viewportDimension.height - paintOffset.dy - box.size.height,
+      AxisDirection.left  => viewportDimension.width - paintOffset.dx - box.size.width,
+      AxisDirection.right => paintOffset.dx,
+      AxisDirection.down  => paintOffset.dy,
     };
 
     // This step assumes the viewport's layout is up-to-date, i.e., if
@@ -980,27 +972,24 @@ abstract class RenderTwoDimensionalViewport extends RenderBox implements RenderA
     final Matrix4 transform = target.getTransformTo(this);
     Rect targetRect = MatrixUtils.transformRect(transform, rect);
 
-    final double mainAxisExtent = switch (axisDirectionToAxis(axisDirection)) {
-      Axis.horizontal => viewportDimension.width,
-      Axis.vertical => viewportDimension.height,
+    final double mainAxisExtentDifference = switch (axis) {
+      Axis.horizontal => viewportDimension.width - rectLocal.width,
+      Axis.vertical   => viewportDimension.height - rectLocal.height,
     };
 
-    final double targetOffset = leadingScrollOffset - (mainAxisExtent - targetMainAxisExtent) * alignment;
+    final double targetOffset = leadingScrollOffset - mainAxisExtentDifference * alignment;
 
-    final double offsetDifference = switch (axisDirectionToAxis(axisDirection)){
-      Axis.vertical => verticalOffset.pixels - targetOffset,
+    final double offsetDifference = switch (axis) {
       Axis.horizontal => horizontalOffset.pixels - targetOffset,
+      Axis.vertical   => verticalOffset.pixels - targetOffset,
+    };
+
+    targetRect = switch (axisDirection) {
+      AxisDirection.up    => targetRect.translate(0.0, -offsetDifference),
+      AxisDirection.down  => targetRect.translate(0.0,  offsetDifference),
+      AxisDirection.left  => targetRect.translate(-offsetDifference, 0.0),
+      AxisDirection.right => targetRect.translate( offsetDifference, 0.0),
     };
-    switch (axisDirection) {
-      case AxisDirection.down:
-        targetRect = targetRect.translate(0.0, offsetDifference);
-      case AxisDirection.right:
-        targetRect = targetRect.translate(offsetDifference, 0.0);
-      case AxisDirection.up:
-        targetRect = targetRect.translate(0.0, -offsetDifference);
-      case AxisDirection.left:
-        targetRect = targetRect.translate(-offsetDifference, 0.0);
-    }
 
     final RevealedOffset revealedOffset = RevealedOffset(
       offset: targetOffset,
@@ -1566,26 +1555,16 @@ abstract class RenderTwoDimensionalViewport extends RenderBox implements RenderA
     // This is only usable once we have sizes.
     assert(hasSize);
     assert(child.hasSize);
-    final double xOffset;
-    final double yOffset;
-    switch (verticalAxisDirection) {
-      case AxisDirection.up:
-        yOffset = viewportDimension.height - (layoutOffset.dy + child.size.height);
-      case AxisDirection.down:
-        yOffset = layoutOffset.dy;
-      case AxisDirection.right:
-      case AxisDirection.left:
-        throw Exception('This should not happen');
-    }
-    switch (horizontalAxisDirection) {
-      case AxisDirection.right:
-        xOffset = layoutOffset.dx;
-      case AxisDirection.left:
-        xOffset = viewportDimension.width - (layoutOffset.dx + child.size.width);
-      case AxisDirection.up:
-      case AxisDirection.down:
-        throw Exception('This should not happen');
-    }
+    final double xOffset = switch (horizontalAxisDirection) {
+      AxisDirection.right => layoutOffset.dx,
+      AxisDirection.left => viewportDimension.width - (layoutOffset.dx + child.size.width),
+      AxisDirection.up || AxisDirection.down => throw Exception('This should not happen'),
+    };
+    final double yOffset = switch (verticalAxisDirection) {
+      AxisDirection.up => viewportDimension.height - (layoutOffset.dy + child.size.height),
+      AxisDirection.down => layoutOffset.dy,
+      AxisDirection.right || AxisDirection.left => throw Exception('This should not happen'),
+    };
     return Offset(xOffset, yOffset);
   }