Fix focus traversal regions to account for transforms. (#55600)

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

@@ -640,38 +640,38 @@ class FocusNode with DiagnosticableTreeMixin, ChangeNotifier {
 
   /// Returns the size of the attached widget's [RenderObject], in logical
   /// units.
-  Size get size {
-    assert(
-        context != null,
-        "Tried to get the size of a focus node that didn't have its context set yet.\n"
-        'The context needs to be set before trying to evaluate traversal policies. This '
-        'is typically done with the attach method.');
-    return context.findRenderObject().semanticBounds.size;
-  }
+  ///
+  /// Size is the size of the transformed widget in global coordinates.
+  Size get size => rect.size;
 
   /// Returns the global offset to the upper left corner of the attached
   /// widget's [RenderObject], in logical units.
+  ///
+  /// Offset is the offset of the transformed widget in global coordinates.
   Offset get offset {
     assert(
         context != null,
         "Tried to get the offset of a focus node that didn't have its context set yet.\n"
-        'The context needs to be set before trying to evaluate traversal policies. This '
-        'is typically done with the attach method.');
+        'The context needs to be set before trying to evaluate traversal policies. '
+        'Setting the context is typically done with the attach method.');
     final RenderObject object = context.findRenderObject();
     return MatrixUtils.transformPoint(object.getTransformTo(null), object.semanticBounds.topLeft);
   }
 
   /// Returns the global rectangle of the attached widget's [RenderObject], in
   /// logical units.
+  ///
+  /// Rect is the rectangle of the transformed widget in global coordinates.
   Rect get rect {
     assert(
         context != null,
         "Tried to get the bounds of a focus node that didn't have its context set yet.\n"
-        'The context needs to be set before trying to evaluate traversal policies. This '
-        'is typically done with the attach method.');
+        'The context needs to be set before trying to evaluate traversal policies. '
+        'Setting the context is typically done with the attach method.');
     final RenderObject object = context.findRenderObject();
-    final Offset globalOffset = MatrixUtils.transformPoint(object.getTransformTo(null), object.semanticBounds.topLeft);
-    return globalOffset & object.semanticBounds.size;
+    final Offset topLeft = MatrixUtils.transformPoint(object.getTransformTo(null), object.semanticBounds.topLeft);
+    final Offset bottomRight = MatrixUtils.transformPoint(object.getTransformTo(null), object.semanticBounds.bottomRight);
+    return Rect.fromLTRB(topLeft.dx, topLeft.dy, bottomRight.dx, bottomRight.dy);
   }
 
   /// Removes the focus on this node by moving the primary focus to another node.

packages/flutter/test/widgets/focus_manager_test.dart

@@ -2,6 +2,8 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+import 'dart:math' as math;
+
 import 'package:flutter/foundation.dart';
 import 'package:flutter/gestures.dart';
 import 'package:flutter/material.dart';
@@ -62,6 +64,39 @@ void main() {
       expect(child2.parent, isNull);
       expect(parent.children, isEmpty);
     });
+    testWidgets('Geometry is transformed properly.', (WidgetTester tester) async {
+      final FocusNode focusNode1 = FocusNode(debugLabel: 'Test Node 1');
+      final FocusNode focusNode2 = FocusNode(debugLabel: 'Test Node 2');
+      await tester.pumpWidget(
+        Padding(
+          padding: const EdgeInsets.all(8.0),
+          child: Column(
+            children: <Widget>[
+              Focus(focusNode: focusNode1, child: Container(width: 200, height: 100),),
+              Transform.translate(
+                offset: const Offset(10, 20),
+                child: Transform.scale(
+                  scale: 0.33,
+                  child: Transform.rotate(
+                    angle: math.pi,
+                    child: Focus(focusNode: focusNode2, child: Container(width: 200, height: 100)),
+                  ),
+                ),
+              ),
+            ],
+          ),
+        ),
+      );
+      focusNode2.requestFocus();
+      await tester.pump();
+
+      expect(focusNode1.rect, equals(const Rect.fromLTRB(300.0, 8.0, 500.0, 108.0)));
+      expect(focusNode2.rect, equals(const Rect.fromLTRB(443.0, 194.5, 377.0, 161.5)));
+      expect(focusNode1.size, equals(const Size(200.0, 100.0)));
+      expect(focusNode2.size, equals(const Size(-66.0, -33.0)));
+      expect(focusNode1.offset, equals(const Offset(300.0, 8.0)));
+      expect(focusNode2.offset, equals(const Offset(443.0, 194.5)));
+    });
     testWidgets('implements debugFillProperties', (WidgetTester tester) async {
       final DiagnosticPropertiesBuilder builder = DiagnosticPropertiesBuilder();
       FocusNode(