Relands "Changing `TextPainter.getOffsetForCaret` implementation to remove the...

Relands "Changing `TextPainter.getOffsetForCaret` implementation to remove the logarithmic search (#143281)" (reverted in #143801) (#143954)

The original PR was reverted because the new caret positioning callpath triggered a skparagraph assert. The assert has been removed. Relanding the PR with no changes applied.

examples/api/test/widgets/text_magnifier/text_magnifier.0_test.dart

@@ -46,8 +46,9 @@ void main() {
   const Duration durationBetweenActions = Duration(milliseconds: 20);
   const String defaultText = 'I am a magnifier, fear me!';
 
-  Future<void> showMagnifier(WidgetTester tester, String characterToTapOn) async {
-    final Offset tapOffset = _textOffsetToPosition(tester, defaultText.indexOf(characterToTapOn));
+  Future<void> showMagnifier(WidgetTester tester, int textOffset) async {
+    assert(textOffset >= 0);
+    final Offset tapOffset = _textOffsetToPosition(tester, textOffset);
 
     // Double tap 'Magnifier' word to show the selection handles.
     final TestGesture testGesture = await tester.startGesture(tapOffset);
@@ -59,11 +60,11 @@ void main() {
     await testGesture.up();
     await tester.pumpAndSettle();
 
-    final TextSelection selection = tester
-        .firstWidget<TextField>(find.byType(TextField))
-        .controller!
-        .selection;
+    final TextEditingController controller = tester
+      .firstWidget<TextField>(find.byType(TextField))
+      .controller!;
 
+    final TextSelection selection = controller.selection;
     final RenderEditable renderEditable = _findRenderEditable(tester);
     final List<TextSelectionPoint> endpoints = _globalize(
       renderEditable.getEndpointsForSelection(selection),
@@ -86,7 +87,7 @@ void main() {
   testWidgets('should show custom magnifier on drag', (WidgetTester tester) async {
     await tester.pumpWidget(const example.TextMagnifierExampleApp(text: defaultText));
 
-    await showMagnifier(tester, 'e');
+    await showMagnifier(tester, defaultText.indexOf('e'));
     expect(find.byType(example.CustomMagnifier), findsOneWidget);
 
     await expectLater(
@@ -96,16 +97,15 @@ void main() {
   }, variant: const TargetPlatformVariant(<TargetPlatform>{ TargetPlatform.iOS, TargetPlatform.android }));
 
 
-  for (final TextDirection textDirection in TextDirection.values) {
-    testWidgets('should show custom magnifier in $textDirection', (WidgetTester tester) async {
-      final String text = textDirection == TextDirection.rtl ? 'أثارت زر' : defaultText;
-      final String textToTapOn = textDirection == TextDirection.rtl ? 'ت' : 'e';
+  testWidgets('should show custom magnifier in RTL', (WidgetTester tester) async {
+    const String text = 'أثارت زر';
+    const String textToTapOn = 'ت';
 
-      await tester.pumpWidget(example.TextMagnifierExampleApp(textDirection: textDirection, text: text));
+    await tester.pumpWidget(const example.TextMagnifierExampleApp(textDirection: TextDirection.rtl, text: text));
 
-      await showMagnifier(tester, textToTapOn);
+    await showMagnifier(tester, text.indexOf(textToTapOn));
+
+    expect(find.byType(example.CustomMagnifier), findsOneWidget);
+  });
 
-      expect(find.byType(example.CustomMagnifier), findsOneWidget);
-    });
-  }
 }

packages/flutter/test/cupertino/text_field_test.dart

@@ -6941,7 +6941,7 @@ void main() {
       // the arrow should not point exactly to the caret because the caret is
       // too close to the right.
       controller.dispose();
-      controller = TextEditingController(text: List<String>.filled(200, 'a').join());
+      controller = TextEditingController(text: 'a' * 200);
       await tester.pumpWidget(
         CupertinoApp(
           debugShowCheckedModeBanner: false,
@@ -7002,7 +7002,7 @@ void main() {
       // Normal centered collapsed selection. The toolbar arrow should point down, and
       // it should point exactly to the caret.
       controller.dispose();
-      controller = TextEditingController(text: List<String>.filled(200, 'a').join());
+      controller = TextEditingController(text: 'a' * 200);
       addTearDown(controller.dispose);
       await tester.pumpWidget(
         CupertinoApp(

packages/flutter/test/material/text_field_test.dart

@@ -15222,6 +15222,8 @@ void main() {
     bool isWide = false;
     const double wideWidth = 300.0;
     const double narrowWidth = 200.0;
+    const TextStyle style = TextStyle(fontSize: 10, height: 1.0, letterSpacing: 0.0, wordSpacing: 0.0);
+    const double caretWidth = 2.0;
     final TextEditingController controller = _textEditingController();
     await tester.pumpWidget(
       boilerplate(
@@ -15234,6 +15236,7 @@ void main() {
                 key: textFieldKey,
                 controller: controller,
                 textDirection: TextDirection.rtl,
+                style: style,
               ),
             );
           },
@@ -15250,15 +15253,17 @@ void main() {
     expect(inputWidth, narrowWidth);
     expect(cursorRight, inputWidth - kCaretGap);
 
-    // After entering some text, the cursor remains on the right of the input.
-    await tester.enterText(find.byType(TextField), '12345');
+    const String text = '12345';
+    // After entering some text, the cursor is placed to the left of the text
+    // because the paragraph's writing direction is RTL.
+    await tester.enterText(find.byType(TextField), text);
     await tester.pump();
     editable = findRenderEditable(tester);
     cursorRight = editable.getLocalRectForCaret(
       TextPosition(offset: controller.value.text.length),
     ).topRight.dx;
     inputWidth = editable.size.width;
-    expect(cursorRight, inputWidth - kCaretGap);
+    expect(cursorRight, inputWidth - kCaretGap - text.length * 10 - caretWidth);
 
     // Since increasing the width of the input moves its right edge further to
     // the right, the cursor has followed this change and still appears on the
@@ -15273,7 +15278,7 @@ void main() {
     ).topRight.dx;
     inputWidth = editable.size.width;
     expect(inputWidth, wideWidth);
-    expect(cursorRight, inputWidth - kCaretGap);
+    expect(cursorRight, inputWidth - kCaretGap - text.length * 10 - caretWidth);
   });
 
   testWidgets('Text selection menu hides after select all on desktop', (WidgetTester tester) async {

packages/flutter/test/painting/text_painter_rtl_test.dart

@@ -301,9 +301,9 @@ void main() {
       painter.getOffsetForCaret(const TextPosition(offset: 2, affinity: TextAffinity.upstream), Rect.zero),
       const Offset(0.0, 10.0),
     );
-    expect( // after the Alef
+    expect( // To the right of the Alef
       painter.getOffsetForCaret(const TextPosition(offset: 2), Rect.zero),
-      const Offset(0.0, 10.0),
+      const Offset(10.0, 10.0),
     );
 
     expect(

packages/flutter/test/widgets/editable_text_cursor_test.dart

@@ -976,7 +976,7 @@ void main() {
     expect(find.byType(EditableText), paints
       ..rrect(
         rrect: RRect.fromRectAndRadius(
-          const Rect.fromLTRB(193.83334350585938, -0.916666666666668, 196.83334350585938, 19.083333969116211),
+          const Rect.fromLTWH(193.83334350585938, -0.916666666666668, 3.0, 20.0),
           const Radius.circular(1.0),
         ),
         color: const Color(0xbf2196f3),
@@ -994,7 +994,7 @@ void main() {
     expect(find.byType(EditableText), paints
       ..rrect(
         rrect: RRect.fromRectAndRadius(
-          const Rect.fromLTRB(719.3333333333333, -0.9166666666666679, 721.3333333333333, 17.083333333333332),
+          const Rect.fromLTWH(719.3333333333333, -0.9166666666666679, 2.0, 18.0),
           const Radius.circular(2.0),
         ),
         color: const Color(0xff999999),