Text selection located wrong position when selecting multiple lines over max lines (#102747)

Fix for text selection toolbar position in cases with overflowing text.

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

@@ -97,13 +97,16 @@ class _CupertinoTextSelectionControlsToolbarState extends State<_CupertinoTextSe
       mediaQuery.size.width - mediaQuery.padding.right - _kArrowScreenPadding,
     );
 
+    final double topAmountInEditableRegion = widget.endpoints.first.point.dy - widget.textLineHeight;
+    final double anchorTop = math.max(topAmountInEditableRegion, 0) + widget.globalEditableRegion.top;
+
     // The y-coordinate has to be calculated instead of directly quoting
     // selectionMidpoint.dy, since the caller
     // (TextSelectionOverlay._buildToolbar) does not know whether the toolbar is
     // going to be facing up or down.
     final Offset anchorAbove = Offset(
       anchorX,
-      widget.endpoints.first.point.dy - widget.textLineHeight + widget.globalEditableRegion.top,
+      anchorTop,
     );
     final Offset anchorBelow = Offset(
       anchorX,

packages/flutter/lib/src/cupertino/text_selection_toolbar.dart

@@ -129,6 +129,7 @@ class CupertinoTextSelectionToolbar extends StatelessWidget {
         delegate: TextSelectionToolbarLayoutDelegate(
           anchorAbove: anchorAbove - localAdjustment - contentPaddingAdjustment,
           anchorBelow: anchorBelow - localAdjustment + contentPaddingAdjustment,
+          fitsAbove: fitsAbove,
         ),
         child: _CupertinoTextSelectionToolbarContent(
           anchor: fitsAbove ? anchorAbove : anchorBelow,

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

@@ -205,9 +205,12 @@ class _TextSelectionControlsToolbarState extends State<_TextSelectionControlsToo
     final TextSelectionPoint endTextSelectionPoint = widget.endpoints.length > 1
       ? widget.endpoints[1]
       : widget.endpoints[0];
+    final double topAmountInEditableRegion = startTextSelectionPoint.point.dy - widget.textLineHeight;
+    final double anchorTop = math.max(topAmountInEditableRegion, 0) + widget.globalEditableRegion.top - _kToolbarContentDistance;
+
     final Offset anchorAbove = Offset(
       widget.globalEditableRegion.left + widget.selectionMidpoint.dx,
-      widget.globalEditableRegion.top + startTextSelectionPoint.point.dy - widget.textLineHeight - _kToolbarContentDistance,
+      anchorTop,
     );
     final Offset anchorBelow = Offset(
       widget.globalEditableRegion.left + widget.selectionMidpoint.dx,

packages/flutter/test/cupertino/text_selection_test.dart

@@ -533,6 +533,69 @@ void main() {
       skip: isBrowser, // [intended] We do not use Flutter-rendered context menu on the Web.
       variant: const TargetPlatformVariant(<TargetPlatform>{ TargetPlatform.iOS }),
     );
+
+    testWidgets(
+      'When selecting multiple lines over max lines',
+      (WidgetTester tester) async {
+        final TextEditingController controller = TextEditingController(text: 'abc\ndef\nghi\njkl\nmno\npqr');
+        await tester.pumpWidget(CupertinoApp(
+          home: Directionality(
+              textDirection: TextDirection.ltr,
+              child: MediaQuery(
+                data: const MediaQueryData(size: Size(800.0, 600.0)),
+                child: Center(
+                  child: CupertinoTextField(
+                    padding: const EdgeInsets.all(8.0),
+                    controller: controller,
+                    maxLines: 2,
+                  ),
+                ),
+              ),
+            ),
+        ));
+
+        // Initially, the menu isn't shown at all.
+        expect(find.text('Cut'), findsNothing);
+        expect(find.text('Copy'), findsNothing);
+        expect(find.text('Paste'), findsNothing);
+        expect(find.text('Select All'), findsNothing);
+        expect(find.text('◀'), findsNothing);
+        expect(find.text('▶'), findsNothing);
+
+        // Long press on an space to show the selection menu.
+        await tester.longPressAt(textOffsetToPosition(tester, 1));
+        await tester.pumpAndSettle();
+        expect(find.text('Cut'), findsNothing);
+        expect(find.text('Copy'), findsNothing);
+        expect(find.text('Paste'), findsOneWidget);
+        expect(find.text('Select All'), findsOneWidget);
+        expect(find.text('◀'), findsNothing);
+        expect(find.text('▶'), findsNothing);
+
+        // Tap to select all.
+        await tester.tap(find.text('Select All'));
+        await tester.pumpAndSettle();
+
+        // Only Cut, Copy, and Paste are shown.
+        expect(find.text('Cut'), findsOneWidget);
+        expect(find.text('Copy'), findsOneWidget);
+        expect(find.text('Paste'), findsOneWidget);
+        expect(find.text('Select All'), findsNothing);
+        expect(find.text('◀'), findsNothing);
+        expect(find.text('▶'), findsNothing);
+
+        // The menu appears at the top of the visible selection.
+        final Offset selectionOffset = tester
+            .getTopLeft(find.byType(CupertinoTextSelectionToolbarButton).first);
+        final Offset textFieldOffset =
+            tester.getTopLeft(find.byType(CupertinoTextField));
+
+        // 7.0 + 43.0 + 8.0 - 8.0 = _kToolbarArrowSize + _kToolbarHeight + _kToolbarContentDistance - padding
+        expect(selectionOffset.dy + 7.0 + 43.0 + 8.0 - 8.0, equals(textFieldOffset.dy));
+      },
+      skip: isBrowser, // [intended] the selection menu isn't required by web
+      variant: const TargetPlatformVariant(<TargetPlatform>{ TargetPlatform.iOS }),
+    );
   });
 
   testWidgets('iOS selection handles scale with rich text (selection style 1)', (WidgetTester tester) async {

packages/flutter/test/material/text_selection_test.dart

@@ -547,6 +547,83 @@ void main() {
       skip: isBrowser, // [intended] We do not use Flutter-rendered context menu on the Web.
       variant: const TargetPlatformVariant(<TargetPlatform>{ TargetPlatform.android }),
     );
+
+    testWidgets(
+      'When selecting multiple lines over max lines',
+      (WidgetTester tester) async {
+        final TextEditingController controller =
+            TextEditingController(text: 'abc\ndef\nghi\njkl\nmno\npqr');
+        await tester.pumpWidget(MaterialApp(
+          theme: ThemeData(platform: TargetPlatform.android),
+          home: Directionality(
+            textDirection: TextDirection.ltr,
+            child: MediaQuery(
+              data: const MediaQueryData(size: Size(800.0, 600.0)),
+              child: Align(
+                alignment: Alignment.bottomCenter,
+                child: Material(
+                  child: TextField(
+                    decoration: const InputDecoration(contentPadding: EdgeInsets.all(8.0)),
+                    style: const TextStyle(fontSize: 32, height: 1),
+                    maxLines: 2,
+                    controller: controller,
+                  ),
+                ),
+              ),
+            ),
+          ),
+        ));
+
+        // Initially, the menu isn't shown at all.
+        expect(find.text('Cut'), findsNothing);
+        expect(find.text('Copy'), findsNothing);
+        expect(find.text('Paste'), findsNothing);
+        expect(find.text('Select all'), findsNothing);
+        expect(find.byType(IconButton), findsNothing);
+
+        // Tap to place the cursor in the field, then tap the handle to show the
+        // selection menu.
+        await tester.tap(find.byType(TextField));
+        await tester.pumpAndSettle();
+        final RenderEditable renderEditable = findRenderEditable(tester);
+        final List<TextSelectionPoint> endpoints = globalize(
+          renderEditable.getEndpointsForSelection(controller.selection),
+          renderEditable,
+        );
+        expect(endpoints.length, 1);
+        final Offset handlePos = endpoints[0].point + const Offset(0.0, 1.0);
+        await tester.tapAt(handlePos, pointer: 7);
+        await tester.pumpAndSettle();
+        expect(find.text('Cut'), findsNothing);
+        expect(find.text('Copy'), findsNothing);
+        expect(find.text('Paste'), findsOneWidget);
+        expect(find.text('Select all'), findsOneWidget);
+        expect(find.byType(IconButton), findsNothing);
+
+        // Tap to select all.
+        await tester.tap(find.text('Select all'));
+        await tester.pumpAndSettle();
+
+        // Only Cut, Copy, and Paste are shown.
+        expect(find.text('Cut'), findsOneWidget);
+        expect(find.text('Copy'), findsOneWidget);
+        expect(find.text('Paste'), findsOneWidget);
+        expect(find.text('Select all'), findsNothing);
+        expect(find.byType(IconButton), findsNothing);
+
+
+        // The menu appears at the top of the visible selection.
+        final Offset selectionOffset = tester
+            .getTopLeft(find.byType(TextSelectionToolbarTextButton).first);
+        final Offset textFieldOffset =
+            tester.getTopLeft(find.byType(TextField));
+
+        // 44.0 + 8.0 - 8.0 = _kToolbarHeight + _kToolbarContentDistance - contentPadding
+        expect(selectionOffset.dy + 44.0 + 8.0 - 8.0, equals(textFieldOffset.dy));
+      },
+      skip: isBrowser, // [intended] the selection menu isn't required by web
+      variant: const TargetPlatformVariant(<TargetPlatform>{ TargetPlatform.android }),
+    );
   });
 
   group('material handles', () {