Cupertino text edit tooltip rework (#34095)

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

@@ -141,6 +141,7 @@ class _MaterialTextSelectionControls extends TextSelectionControls {
   Widget buildToolbar(
     BuildContext context,
     Rect globalEditableRegion,
+    double textLineHeight,
     Offset position,
     List<TextSelectionPoint> endpoints,
     TextSelectionDelegate delegate,

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

@@ -108,12 +108,16 @@ abstract class TextSelectionControls {
   /// [globalEditableRegion] is the TextField size of the global coordinate system
   /// in logical pixels.
   ///
+  /// [textLineHeight] is the `preferredLineHeight` of the [RenderEditable] we
+  /// are building a toolbar for.
+  ///
   /// The [position] is a general calculation midpoint parameter of the toolbar.
   /// If you want more detailed position information, can use [endpoints]
   /// to calculate it.
   Widget buildToolbar(
     BuildContext context,
     Rect globalEditableRegion,
+    double textLineHeight,
     Offset position,
     List<TextSelectionPoint> endpoints,
     TextSelectionDelegate delegate,
@@ -509,19 +513,29 @@ class TextSelectionOverlay {
       return Container();
 
     // Find the horizontal midpoint, just above the selected text.
-    final List<TextSelectionPoint> endpoints = renderObject.getEndpointsForSelection(_selection);
-    final Offset midpoint = Offset(
-      (endpoints.length == 1) ?
-        endpoints[0].point.dx :
-        (endpoints[0].point.dx + endpoints[1].point.dx) / 2.0,
-      endpoints[0].point.dy - renderObject.preferredLineHeight,
-    );
+    final List<TextSelectionPoint> endpoints =
+        renderObject.getEndpointsForSelection(_selection);
 
     final Rect editingRegion = Rect.fromPoints(
       renderObject.localToGlobal(Offset.zero),
       renderObject.localToGlobal(renderObject.size.bottomRight(Offset.zero)),
     );
 
+    final bool isMultiline = endpoints.last.point.dy - endpoints.first.point.dy >
+          renderObject.preferredLineHeight / 2;
+
+    // If the selected text spans more than 1 line, horizontally center the toolbar.
+    // Derived from both iOS and Android.
+    final double midX = isMultiline
+      ? editingRegion.width / 2
+      : (endpoints.first.point.dx + endpoints.last.point.dx) / 2;
+
+    final Offset midpoint = Offset(
+      midX,
+      // The y-coordinate won't be made use of most likely.
+      endpoints[0].point.dy - renderObject.preferredLineHeight,
+    );
+
     return FadeTransition(
       opacity: _toolbarOpacity,
       child: CompositedTransformFollower(
@@ -531,6 +545,7 @@ class TextSelectionOverlay {
         child: selectionControls.buildToolbar(
           context,
           editingRegion,
+          renderObject.preferredLineHeight,
           midpoint,
           endpoints,
           selectionDelegate,

packages/flutter/test/material/text_field_test.dart

@@ -15,6 +15,7 @@ import 'package:flutter/services.dart';
 import 'package:flutter/foundation.dart';
 import 'package:flutter/gestures.dart' show DragStartBehavior, PointerDeviceKind;
 
+import '../rendering/mock_canvas.dart';
 import '../widgets/semantics_tester.dart';
 import 'feedback_tester.dart';
 
@@ -864,7 +865,7 @@ void main() {
     expect(find.text('CUT'), findsNothing);
   });
 
-  testWidgets('text field build empty tool bar when no options available ios', (WidgetTester tester) async {
+  testWidgets('does not paint tool bar when no options available on ios', (WidgetTester tester) async {
     await tester.pumpWidget(
         MaterialApp(
           theme: ThemeData(platform: TargetPlatform.iOS),
@@ -882,11 +883,8 @@ void main() {
     await tester.tap(find.byType(TextField));
     // Wait for context menu to be built.
     await tester.pumpAndSettle();
-    final RenderBox container = tester.renderObject(find.descendant(
-      of: find.byType(FadeTransition),
-      matching: find.byType(Container),
-    ));
-    expect(container.size, Size.zero);
+
+    expect(find.byType(CupertinoTextSelectionToolbar), paintsNothing);
   });
 
   testWidgets('text field build empty tool bar when no options available android', (WidgetTester tester) async {

packages/flutter/test/widgets/editable_text_test.dart

@@ -1546,7 +1546,7 @@ void main() {
 
       controls = MockTextSelectionControls();
       when(controls.buildHandle(any, any, any)).thenReturn(Container());
-      when(controls.buildToolbar(any, any, any, any, any))
+      when(controls.buildToolbar(any, any, any, any, any, any))
           .thenReturn(Container());
     });
 

packages/flutter_test/lib/src/matchers.dart

@@ -1108,7 +1108,8 @@ class _IsWithinDistance<T> extends Matcher {
 }
 
 class _MoreOrLessEquals extends Matcher {
-  const _MoreOrLessEquals(this.value, this.epsilon);
+  const _MoreOrLessEquals(this.value, this.epsilon)
+    : assert(epsilon >= 0);
 
   final double value;
   final double epsilon;
@@ -1125,6 +1126,12 @@ class _MoreOrLessEquals extends Matcher {
 
   @override
   Description describe(Description description) => description.add('$value (±$epsilon)');
+
+  @override
+  Description describeMismatch(Object item, Description mismatchDescription, Map<dynamic, dynamic> matchState, bool verbose) {
+    return super.describeMismatch(item, mismatchDescription, matchState, verbose)
+      ..add('$item is not in the range of $value (±$epsilon).');
+  }
 }
 
 class _IsMethodCall extends Matcher {