TextPainter RTL (#11888)

bin/internal/engine.version

@@ -1 +1 @@
-ccf68cdcb66f9fe354bf3e8472bb0b47c83e8ac9
+2d7c30033d76fda9779462827ad5322d78e1fb3a

examples/hello_world/README.md

@@ -0,0 +1,7 @@
+```
+# To run the Hello World demo:
+flutter run
+
+# To run the Hello World demo showing Arabic:
+flutter run lib/arabic.dart
+```

examples/hello_world/lib/arabic.dart

@@ -0,0 +1,7 @@
+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'package:flutter/widgets.dart';
+
+void main() => runApp(const Center(child: const Text('برنامج أهلا بالعالم', textDirection: TextDirection.rtl)));

examples/hello_world/lib/main.dart

@@ -4,4 +4,4 @@
 
 import 'package:flutter/widgets.dart';
 
-void main() => runApp(const Center(child: const Text('Hello, world!')));
+void main() => runApp(const Center(child: const Text('Hello, world!', textDirection: TextDirection.ltr)));

examples/layers/lib/main.dart

@@ -4,4 +4,4 @@
 
 import 'package:flutter/widgets.dart';
 
-void main() => runApp(const Center(child: const Text('flutter run -t xxx/yyy.dart')));
+void main() => runApp(const Center(child: const Text('flutter run -t xxx/yyy.dart', textDirection: TextDirection.ltr)));

examples/layers/raw/hello_world.dart

@@ -11,7 +11,9 @@ void beginFrame(Duration timeStamp) {
   final double devicePixelRatio = ui.window.devicePixelRatio;
   final ui.Size logicalSize = ui.window.physicalSize / devicePixelRatio;
 
-  final ui.ParagraphBuilder paragraphBuilder = new ui.ParagraphBuilder(new ui.ParagraphStyle())
+  final ui.ParagraphBuilder paragraphBuilder = new ui.ParagraphBuilder(
+    new ui.ParagraphStyle(textDirection: ui.TextDirection.ltr),
+  )
     ..addText('Hello, world.');
   final ui.Paragraph paragraph = paragraphBuilder.build()
     ..layout(new ui.ParagraphConstraints(width: logicalSize.width));

examples/layers/raw/text.dart

@@ -52,7 +52,13 @@ void beginFrame(Duration timeStamp) {
 
 void main() {
   // To create a paragraph of text, we use ParagraphBuilder.
-  final ui.ParagraphBuilder builder = new ui.ParagraphBuilder(new ui.ParagraphStyle())
+  final ui.ParagraphBuilder builder = new ui.ParagraphBuilder(
+    // The text below has a primary direction of left-to-right.
+    // The embedded text has other directions.
+    // If this was TextDirection.rtl, the "Hello, world" text would end up on
+    // the other side of the right-to-left text.
+    new ui.ParagraphStyle(textDirection: ui.TextDirection.ltr),
+  )
     // We first push a style that turns the text blue.
     ..pushStyle(new ui.TextStyle(color: const ui.Color(0xFF0000FF)))
     ..addText('Hello, ')

examples/layers/rendering/flex_layout.dart

@@ -14,24 +14,36 @@ void main() {
 
   void addAlignmentRow(CrossAxisAlignment crossAxisAlignment) {
     TextStyle style = const TextStyle(color: const Color(0xFF000000));
-    final RenderParagraph paragraph = new RenderParagraph(new TextSpan(style: style, text: '$crossAxisAlignment'));
+    final RenderParagraph paragraph = new RenderParagraph(
+      new TextSpan(style: style, text: '$crossAxisAlignment'),
+      textDirection: TextDirection.ltr,
+    );
     table.add(new RenderPadding(child: paragraph, padding: const EdgeInsets.only(top: 20.0)));
     final RenderFlex row = new RenderFlex(crossAxisAlignment: crossAxisAlignment, textBaseline: TextBaseline.alphabetic);
     style = const TextStyle(fontSize: 15.0, color: const Color(0xFF000000));
     row.add(new RenderDecoratedBox(
       decoration: const BoxDecoration(color: const Color(0x7FFFCCCC)),
-      child: new RenderParagraph(new TextSpan(style: style, text: 'foo foo foo'))
+      child: new RenderParagraph(
+        new TextSpan(style: style, text: 'foo foo foo'),
+        textDirection: TextDirection.ltr,
+      ),
     ));
     style = const TextStyle(fontSize: 10.0, color: const Color(0xFF000000));
     row.add(new RenderDecoratedBox(
       decoration: const BoxDecoration(color: const Color(0x7FCCFFCC)),
-      child: new RenderParagraph(new TextSpan(style: style, text: 'foo foo foo'))
+      child: new RenderParagraph(
+        new TextSpan(style: style, text: 'foo foo foo'),
+        textDirection: TextDirection.ltr,
+      ),
     ));
     final RenderFlex subrow = new RenderFlex(crossAxisAlignment: crossAxisAlignment, textBaseline: TextBaseline.alphabetic);
     style = const TextStyle(fontSize: 25.0, color: const Color(0xFF000000));
     subrow.add(new RenderDecoratedBox(
       decoration: const BoxDecoration(color: const Color(0x7FCCCCFF)),
-      child: new RenderParagraph(new TextSpan(style: style, text: 'foo foo foo foo'))
+      child: new RenderParagraph(
+        new TextSpan(style: style, text: 'foo foo foo foo'),
+        textDirection: TextDirection.ltr,
+      ),
     ));
     subrow.add(new RenderSolidColorBox(const Color(0x7FCCFFFF), desiredSize: const Size(30.0, 40.0)));
     row.add(subrow);
@@ -48,7 +60,10 @@ void main() {
 
   void addJustificationRow(MainAxisAlignment justify) {
     const TextStyle style = const TextStyle(color: const Color(0xFF000000));
-    final RenderParagraph paragraph = new RenderParagraph(new TextSpan(style: style, text: '$justify'));
+    final RenderParagraph paragraph = new RenderParagraph(
+      new TextSpan(style: style, text: '$justify'),
+      textDirection: TextDirection.ltr,
+    );
     table.add(new RenderPadding(child: paragraph, padding: const EdgeInsets.only(top: 20.0)));
     final RenderFlex row = new RenderFlex(direction: Axis.horizontal);
     row.add(new RenderSolidColorBox(const Color(0xFFFFCCCC), desiredSize: const Size(80.0, 60.0)));

examples/layers/rendering/hello_world.dart

@@ -16,7 +16,14 @@ void main() {
       alignment: FractionalOffset.center,
       // We use a RenderParagraph to display the text 'Hello, world.' without
       // any explicit styling.
-      child: new RenderParagraph(const TextSpan(text: 'Hello, world.'))
+      child: new RenderParagraph(
+        const TextSpan(text: 'Hello, world.'),
+        // The text is in English so we specify the text direction as
+        // left-to-right. If the text had been in Hebrew or Arabic, we would
+        // have specified right-to-left. The Flutter framework does not assume a
+        // particular text direction.
+        textDirection: TextDirection.ltr,
+      ),
     )
   );
 }

examples/layers/rendering/touch_input.dart

@@ -104,8 +104,9 @@ void main() {
   final RenderParagraph paragraph = new RenderParagraph(
     const TextSpan(
       style: const TextStyle(color: Colors.black87),
-      text: "Touch me!"
-    )
+      text: "Touch me!",
+    ),
+    textDirection: TextDirection.ltr,
   );
   // A stack is a render object that layers its children on top of each other.
   // The bottom later is our RenderDots object, and on top of that we show the
@@ -114,7 +115,7 @@ void main() {
     children: <RenderBox>[
       new RenderDots(),
       paragraph,
-    ]
+    ],
   );
   // The "parentData" field of a render object is controlled by the render
   // object's parent render object. Now that we've added the paragraph as a

examples/layers/test/smoketests/lib/main_test.dart

@@ -0,0 +1,13 @@
+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'package:test/test.dart';
+
+import '../../../lib/main.dart' as demo;
+
+void main() {
+  test('layers smoketest for lib/main.dart', () {
+    demo.main();
+  });
+}

examples/layers/test/smoketests/raw/canvas_test.dart

@@ -0,0 +1,13 @@
+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'package:test/test.dart';
+
+import '../../../raw/canvas.dart' as demo;
+
+void main() {
+  test('layers smoketest for raw/canvas.dart', () {
+    demo.main();
+  });
+}

examples/layers/test/smoketests/raw/hello_world_test.dart

@@ -0,0 +1,13 @@
+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'package:test/test.dart';
+
+import '../../../raw/hello_world.dart' as demo;
+
+void main() {
+  test('layers smoketest for raw/hello_world.dart', () {
+    demo.main();
+  });
+}

examples/layers/test/smoketests/raw/spinning_square_test.dart

@@ -0,0 +1,13 @@
+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'package:test/test.dart';
+
+import '../../../raw/spinning_square.dart' as demo;
+
+void main() {
+  test('layers smoketest for raw/spinning_square.dart', () {
+    demo.main();
+  });
+}

examples/layers/test/smoketests/raw/text_test.dart

@@ -0,0 +1,13 @@
+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'package:test/test.dart';
+
+import '../../../raw/text.dart' as demo;
+
+void main() {
+  test('layers smoketest for raw/text.dart', () {
+    demo.main();
+  });
+}

examples/layers/test/smoketests/raw/touch_input_test.dart

@@ -0,0 +1,13 @@
+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'package:test/test.dart';
+
+import '../../../raw/touch_input.dart' as demo;
+
+void main() {
+  test('layers smoketest for raw/touch_input.dart', () {
+    demo.main();
+  });
+}

examples/layers/test/smoketests/rendering/custom_coordinate_systems_test.dart

@@ -0,0 +1,13 @@
+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'package:test/test.dart';
+
+import '../../../rendering/custom_coordinate_systems.dart' as demo;
+
+void main() {
+  test('layers smoketest for rendering/custom_coordinate_systems.dart', () {
+    demo.main();
+  });
+}

examples/layers/test/smoketests/rendering/flex_layout_test.dart

@@ -0,0 +1,13 @@
+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'package:test/test.dart';
+
+import '../../../rendering/flex_layout.dart' as demo;
+
+void main() {
+  test('layers smoketest for rendering/flex_layout.dart', () {
+    demo.main();
+  });
+}

examples/layers/test/smoketests/rendering/hello_world_test.dart

@@ -0,0 +1,13 @@
+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'package:test/test.dart';
+
+import '../../../rendering/hello_world.dart' as demo;
+
+void main() {
+  test('layers smoketest for rendering/hello_world.dart', () {
+    demo.main();
+  });
+}

examples/layers/test/smoketests/rendering/spinning_square_test.dart

@@ -0,0 +1,13 @@
+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'package:test/test.dart';
+
+import '../../../rendering/spinning_square.dart' as demo;
+
+void main() {
+  test('layers smoketest for rendering/spinning_square.dart', () {
+    demo.main();
+  });
+}

examples/layers/test/smoketests/rendering/touch_input_test.dart

@@ -0,0 +1,13 @@
+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'package:test/test.dart';
+
+import '../../../rendering/touch_input.dart' as demo;
+
+void main() {
+  test('layers smoketest for rendering/touch_input.dart', () {
+    demo.main();
+  });
+}

examples/layers/test/smoketests/services/isolate_test.dart

@@ -0,0 +1,13 @@
+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'package:test/test.dart';
+
+import '../../../services/isolate.dart' as demo;
+
+void main() {
+  test('layers smoketest for services/isolate.dart', () {
+    demo.main();
+  });
+}

examples/layers/test/smoketests/services/lifecycle_test.dart

@@ -0,0 +1,13 @@
+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'package:test/test.dart';
+
+import '../../../services/lifecycle.dart' as demo;
+
+void main() {
+  test('layers smoketest for services/lifecycle.dart', () {
+    demo.main();
+  });
+}

examples/layers/test/smoketests/widgets/custom_render_box_test.dart

@@ -0,0 +1,13 @@
+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'package:test/test.dart';
+
+import '../../../widgets/custom_render_box.dart' as demo;
+
+void main() {
+  test('layers smoketest for widgets/custom_render_box.dart', () {
+    demo.main();
+  });
+}

examples/layers/test/smoketests/widgets/gestures_test.dart

@@ -0,0 +1,13 @@
+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'package:test/test.dart';
+
+import '../../../widgets/gestures.dart' as demo;
+
+void main() {
+  test('layers smoketest for widgets/gestures.dart', () {
+    demo.main();
+  });
+}

examples/layers/test/smoketests/widgets/hello_world_test.dart

@@ -0,0 +1,13 @@
+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'package:test/test.dart';
+
+import '../../../widgets/hello_world.dart' as demo;
+
+void main() {
+  test('layers smoketest for widgets/hello_world.dart', () {
+    demo.main();
+  });
+}

examples/layers/test/smoketests/widgets/media_query_test.dart

@@ -0,0 +1,13 @@
+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'package:test/test.dart';
+
+import '../../../widgets/media_query.dart' as demo;
+
+void main() {
+  test('layers smoketest for widgets/media_query.dart', () {
+    demo.main();
+  });
+}

examples/layers/test/smoketests/widgets/sectors_test.dart

@@ -0,0 +1,13 @@
+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'package:test/test.dart';
+
+import '../../../widgets/sectors.dart' as demo;
+
+void main() {
+  test('layers smoketest for widgets/sectors.dart', () {
+    demo.main();
+  });
+}

examples/layers/test/smoketests/widgets/spinning_mixed_test.dart

@@ -0,0 +1,13 @@
+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'package:test/test.dart';
+
+import '../../../widgets/spinning_mixed.dart' as demo;
+
+void main() {
+  test('layers smoketest for widgets/spinning_mixed.dart', () {
+    demo.main();
+  });
+}

examples/layers/test/smoketests/widgets/spinning_square_test.dart

@@ -0,0 +1,13 @@
+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'package:test/test.dart';
+
+import '../../../widgets/spinning_square.dart' as demo;
+
+void main() {
+  test('layers smoketest for widgets/spinning_square.dart', () {
+    demo.main();
+  });
+}

examples/layers/test/smoketests/widgets/styled_text_test.dart

@@ -0,0 +1,13 @@
+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'package:test/test.dart';
+
+import '../../../widgets/styled_text.dart' as demo;
+
+void main() {
+  test('layers smoketest for widgets/styled_text.dart', () {
+    demo.main();
+  });
+}

examples/layers/widgets/hello_world.dart

@@ -4,4 +4,4 @@
 
 import 'package:flutter/widgets.dart';
 
-void main() => runApp(const Center(child: const Text('Hello, world!')));
+void main() => runApp(const Center(child: const Text('Hello, world!', textDirection: TextDirection.ltr)));

examples/layers/widgets/spinning_mixed.dart

@@ -37,6 +37,8 @@ BuildOwner owner = new BuildOwner();
 void attachWidgetTreeToRenderTree(RenderProxyBox container) {
   element = new RenderObjectToWidgetAdapter<RenderBox>(
     container: container,
+    child: new Directionality(
+      textDirection: TextDirection.ltr,
       child: new Container(
         height: 300.0,
         child: new Column(
@@ -53,24 +55,25 @@ void attachWidgetTreeToRenderTree(RenderProxyBox container) {
                         children: <Widget>[
                           new Image.network('https://flutter.io/images/favicon.png'),
                           const Text('PRESS ME'),
-                      ]
+                        ],
                       ),
                       onPressed: () {
                         value = value == null ? 0.1 : (value + 0.1) % 1.0;
                         attachWidgetTreeToRenderTree(container);
-                    }
+                      },
                     ),
                     new CircularProgressIndicator(value: value),
                   ],
-                mainAxisAlignment: MainAxisAlignment.spaceAround
-              )
-            )
+                  mainAxisAlignment: MainAxisAlignment.spaceAround,
+                ),
+              ),
             ),
             const Rectangle(const Color(0xFFFFFF00)),
           ],
-        mainAxisAlignment: MainAxisAlignment.spaceBetween
-      )
-    )
+          mainAxisAlignment: MainAxisAlignment.spaceBetween,
+        ),
+      ),
+    ),
   ).attachToRenderTree(owner, element);
 }
 

packages/flutter/lib/foundation.dart

@@ -46,3 +46,4 @@ export 'src/foundation/print.dart';
 export 'src/foundation/profile.dart';
 export 'src/foundation/serialization.dart';
 export 'src/foundation/synchronous_future.dart';
+export 'src/foundation/unicode.dart';

packages/flutter/lib/src/foundation/unicode.dart

@@ -0,0 +1,98 @@
+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+/// Constants for useful Unicode characters.
+///
+/// Currently, these characters are all related to bidirectional text.
+///
+/// See also:
+///
+///  * <http://unicode.org/reports/tr9/>, which describes the Unicode
+///    bidirectional text algorithm.
+class Unicode {
+  Unicode._();
+  /// U+202A LEFT-TO-RIGHT EMBEDDING
+  ///
+  /// Treat the following text as embedded left-to-right.
+  ///
+  /// Use [PDF] to end the embedding.
+  static const String LRE = '\u202A';
+
+  /// U+202B RIGHT-TO-LEFT EMBEDDING
+  ///
+  /// Treat the following text as embedded right-to-left.
+  ///
+  /// Use [PDF] to end the embedding.
+  static const String RLE = '\u202B';
+
+  /// U+202C POP DIRECTIONAL FORMATTING
+  ///
+  /// End the scope of the last [LRE], [RLE], [RLO], or [LRO].
+  static const String PDF = '\u202C';
+
+  /// U+202A LEFT-TO-RIGHT OVERRIDE
+  ///
+  /// Force following characters to be treated as strong left-to-right characters.
+  ///
+  /// For example, this causes Hebrew text to render backwards.
+  ///
+  /// Use [PDF] to end the override.
+  static const String LRO = '\u202D';
+
+  /// U+202B RIGHT-TO-LEFT OVERRIDE
+  ///
+  /// Force following characters to be treated as strong right-to-left characters.
+  ///
+  /// For example, this causes English text to render backwards.
+  ///
+  /// Use [PDF] to end the override.
+  static const String RLO = '\u202E';
+
+  /// U+2066 LEFT-TO-RIGHT ISOLATE
+  ///
+  /// Treat the following text as isolated and left-to-right.
+  ///
+  /// Use [PDI] to end the isolated scope.
+  static const String LRI = '\u2066';
+
+  /// U+2067 RIGHT-TO-LEFT ISOLATE
+  ///
+  /// Treat the following text as isolated and right-to-left.
+  ///
+  /// Use [PDI] to end the isolated scope.
+  static const String RLI = '\u2067';
+
+  /// U+2068 FIRST STRONG ISOLATE
+  ///
+  /// Treat the following text as isolated and in the direction of its first
+  /// strong directional character that is not inside a nested isolate.
+  ///
+  /// This essentially "autodetects" the directionality of the text. It is not
+  /// 100% reliable. For example, Arabic text that starts with an English quote
+  /// will be detected as LTR, not RTL, which will lead to the text being in a
+  /// weird order.
+  ///
+  /// Use [PDI] to end the isolated scope.
+  static const String FSI = '\u2068';
+
+  /// U+2069 POP DIRECTIONAL ISOLATE
+  ///
+  /// End the scope of the last [LRI], [RLI], or [FSI].
+  static const String PDI = '\u2069';
+
+  /// U+200E LEFT-TO-RIGHT MARK
+  ///
+  /// Left-to-right zero-width character.
+  static const String LRM = '\u200E';
+
+  /// U+200F RIGHT-TO-LEFT MARK
+  ///
+  /// Right-to-left zero-width non-Arabic character.
+  static const String RLM = '\u200F';
+
+  /// U+061C ARABIC LETTER MARK
+  ///
+  /// Right-to-left zero-width Arabic character.
+  static const String ALM = '\u061C';
+}

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

@@ -295,6 +295,7 @@ class _RenderSlider extends RenderBox implements SemanticsActionHandler {
     @required TextDirection textDirection,
   }) : assert(value != null && value >= 0.0 && value <= 1.0),
        assert(textDirection != null),
+       _label = label,
        _value = value,
        _divisions = divisions,
        _activeColor = activeColor,
@@ -303,7 +304,7 @@ class _RenderSlider extends RenderBox implements SemanticsActionHandler {
        _textTheme = textTheme,
        _onChanged = onChanged,
        _textDirection = textDirection {
-    this.label = label;
+    _updateLabelPainter();
     final GestureArenaTeam team = new GestureArenaTeam();
     _drag = new HorizontalDragGestureRecognizer()
       ..team = team
@@ -356,19 +357,7 @@ class _RenderSlider extends RenderBox implements SemanticsActionHandler {
     if (value == _label)
       return;
     _label = value;
-    if (value != null) {
-      // TODO(abarth): Handle textScaleFactor.
-      // https://github.com/flutter/flutter/issues/5938
-      _labelPainter
-        ..text = new TextSpan(
-          style: _textTheme.body1.copyWith(fontSize: 10.0),
-          text: value
-        )
-        ..layout();
-    } else {
-      _labelPainter.text = null;
-    }
-    markNeedsLayout();
+    _updateLabelPainter();
   }
 
   Color get activeColor => _activeColor;
@@ -424,11 +413,29 @@ class _RenderSlider extends RenderBox implements SemanticsActionHandler {
   TextDirection _textDirection;
   set textDirection(TextDirection value) {
     assert(value != null);
-    if (_textDirection == value)
+    if (value == _textDirection)
       return;
     _textDirection = value;
-    // TODO(abarth): Update _labelPainter's text direction.
-    markNeedsPaint();
+    _updateLabelPainter();
+  }
+
+  void _updateLabelPainter() {
+    if (label != null) {
+      // TODO(abarth): Handle textScaleFactor. https://github.com/flutter/flutter/issues/5938
+      _labelPainter
+        ..text = new TextSpan(
+          style: _textTheme.body1.copyWith(fontSize: 10.0),
+          text: label,
+        )
+        ..textDirection = textDirection
+        ..layout();
+    } else {
+      _labelPainter.text = null;
+    }
+    // Changing the textDirection can result in the layout changing, because the
+    // bidi algorithm might line up the glyphs differently which can result in
+    // different ligatures, different shapes, etc. So we always markNeedsLayout.
+    markNeedsLayout();
   }
 
   double get _trackLength => size.width - 2.0 * _kReactionRadius;
@@ -633,7 +640,6 @@ class _RenderSlider extends RenderBox implements SemanticsActionHandler {
           ..lineTo(center.dx + tipAttachment, center.dy + tipAttachment)
           ..close();
         canvas.drawPath(path, primaryPaint);
-        _labelPainter.layout();
         final Offset labelOffset = new Offset(
           center.dx - _labelPainter.width / 2.0,
           center.dy - _labelPainter.height / 2.0

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

@@ -69,8 +69,8 @@ class TextField extends StatefulWidget {
   /// the number of lines. By default, it is 1, meaning this is a single-line
   /// text field. If it is not null, it must be greater than zero.
   ///
-  /// The [keyboardType], [autofocus], [obscureText], and [autocorrect] arguments
-  /// must not be null.
+  /// The [keyboardType], [textAlign], [autofocus], [obscureText], and
+  /// [autocorrect] arguments must not be null.
   const TextField({
     Key key,
     this.controller,
@@ -78,7 +78,7 @@ class TextField extends StatefulWidget {
     this.decoration: const InputDecoration(),
     this.keyboardType: TextInputType.text,
     this.style,
-    this.textAlign,
+    this.textAlign: TextAlign.start,
     this.autofocus: false,
     this.obscureText: false,
     this.autocorrect: true,
@@ -87,6 +87,7 @@ class TextField extends StatefulWidget {
     this.onSubmitted,
     this.inputFormatters,
   }) : assert(keyboardType != null),
+       assert(textAlign != null),
        assert(autofocus != null),
        assert(obscureText != null),
        assert(autocorrect != null),
@@ -125,6 +126,8 @@ class TextField extends StatefulWidget {
   final TextStyle style;
 
   /// How the text being edited should be aligned horizontally.
+  ///
+  /// Defaults to [TextAlign.start].
   final TextAlign textAlign;
 
   /// Whether this text field should focus itself if nothing else is already

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

@@ -356,7 +356,8 @@ List<TextPainter> _initPainters(TextTheme textTheme, List<String> labels) {
     // TODO(abarth): Handle textScaleFactor.
     // https://github.com/flutter/flutter/issues/5939
     painters[i] = new TextPainter(
-      text: new TextSpan(style: style, text: label)
+      text: new TextSpan(style: style, text: label),
+      textDirection: TextDirection.ltr,
     )..layout();
   }
   return painters;

packages/flutter/lib/src/painting/flutter_logo.dart

@@ -247,9 +247,10 @@ class _FlutterLogoPainter extends BoxPainter {
           fontFamily: 'Roboto',
           fontSize: 100.0 * 350.0 / 247.0, // 247 is the height of the F when the fontSize is 350, assuming device pixel ratio 1.0
           fontWeight: FontWeight.w300,
-          textBaseline: TextBaseline.alphabetic
-        )
-      )
+          textBaseline: TextBaseline.alphabetic,
+        ),
+      ),
+      textDirection: TextDirection.ltr,
     );
     _textPainter.layout();
     final ui.TextBox textSize = _textPainter.getBoxesForSelection(const TextSelection(baseOffset: 0, extentOffset: kLabel.length)).single;

packages/flutter/lib/src/painting/text_painter.dart

@@ -33,21 +33,26 @@ final String _kZeroWidthSpace = new String.fromCharCode(0x200B);
 class TextPainter {
   /// Creates a text painter that paints the given text.
   ///
-  /// The text argument is optional but [text] must be non-null before calling
-  /// [layout].
+  /// The `text` and `textDirection` arguments are optional but [text] and
+  /// [textDirection] must be non-null before calling [layout].
+  ///
+  /// The [textAlign] property must not be null.
   ///
   /// The [maxLines] property, if non-null, must be greater than zero.
   TextPainter({
     TextSpan text,
-    TextAlign textAlign,
+    TextAlign textAlign: TextAlign.start,
+    TextDirection textDirection,
     double textScaleFactor: 1.0,
     int maxLines,
     String ellipsis,
   }) : assert(text == null || text.debugAssertIsValid()),
+       assert(textAlign != null),
        assert(textScaleFactor != null),
        assert(maxLines == null || maxLines > 0),
        _text = text,
        _textAlign = textAlign,
+       _textDirection = textDirection,
        _textScaleFactor = textScaleFactor,
        _maxLines = maxLines,
        _ellipsis = ellipsis;
@@ -58,6 +63,8 @@ class TextPainter {
   /// The (potentially styled) text to paint.
   ///
   /// After this is set, you must call [layout] before the next call to [paint].
+  ///
+  /// This and [textDirection] must be non-null before you call [layout].
   TextSpan get text => _text;
   TextSpan _text;
   set text(TextSpan value) {
@@ -74,9 +81,12 @@ class TextPainter {
   /// How the text should be aligned horizontally.
   ///
   /// After this is set, you must call [layout] before the next call to [paint].
+  ///
+  /// The [textAlign] property must not be null. It defaults to [TextAlign.start].
   TextAlign get textAlign => _textAlign;
   TextAlign _textAlign;
   set textAlign(TextAlign value) {
+    assert(value != null);
     if (_textAlign == value)
       return;
     _textAlign = value;
@@ -84,6 +94,32 @@ class TextPainter {
     _needsLayout = true;
   }
 
+  /// The default directionality of the text.
+  ///
+  /// This controls how the [TextAlign.start], [TextAlign.end], and
+  /// [TextAlign.justify] values of [textAlign] are resolved.
+  ///
+  /// This is also used to disambiguate how to render bidirectional text. For
+  /// example, if the [text] is an English phrase followed by a Hebrew phrase,
+  /// in a [TextDirection.ltr] context the English phrase will be on the left
+  /// and the Hebrew phrase to its right, while in a [TextDirection.rtl]
+  /// context, the English phrase will be on the right and the Hebrow phrase on
+  /// its left.
+  ///
+  /// After this is set, you must call [layout] before the next call to [paint].
+  ///
+  /// This and [text] must be non-null before you call [layout].
+  TextDirection get textDirection => _textDirection;
+  TextDirection _textDirection;
+  set textDirection(TextDirection value) {
+    if (_textDirection == value)
+      return;
+    _textDirection = value;
+    _paragraph = null;
+    _layoutTemplate = null; // Shouldn't really matter, but for strict correctness...
+    _needsLayout = true;
+  }
+
   /// The number of font pixels for each logical pixel.
   ///
   /// For example, if the text scale factor is 1.5, text will be 50% larger than
@@ -149,14 +185,20 @@ class TextPainter {
 
   ui.Paragraph _layoutTemplate;
 
-  ui.ParagraphStyle _createParagraphStyle() {
+  ui.ParagraphStyle _createParagraphStyle([TextDirection defaultTextDirection]) {
+    // The defaultTextDirection argument is used for preferredLineHeight in case
+    // textDirection hasn't yet been set.
+    assert(textAlign != null);
+    assert(textDirection != null || defaultTextDirection != null, 'TextPainter.textDirection must be set to a non-null value before using the TextPainter.');
     return _text.style?.getParagraphStyle(
       textAlign: textAlign,
+      textDirection: textDirection ?? defaultTextDirection,
       textScaleFactor: textScaleFactor,
       maxLines: _maxLines,
       ellipsis: _ellipsis,
     ) ?? new ui.ParagraphStyle(
       textAlign: textAlign,
+      textDirection: textDirection ?? defaultTextDirection,
       maxLines: maxLines,
       ellipsis: ellipsis,
     );
@@ -169,11 +211,17 @@ class TextPainter {
   /// relative a typical line of text.
   ///
   /// Obtaining this value does not require calling [layout].
+  ///
+  /// The style of the [text] property is used to determine the font settings
+  /// that contribute to the [preferredLineHeight]. If [text] is null or if it
+  /// specifies no styles, the default [TextStyle] values are used (a 10 pixel
+  /// sans-serif font).
   double get preferredLineHeight {
-    assert(text != null);
     if (_layoutTemplate == null) {
-      final ui.ParagraphBuilder builder = new ui.ParagraphBuilder(_createParagraphStyle());
-      if (text.style != null)
+      final ui.ParagraphBuilder builder = new ui.ParagraphBuilder(
+        _createParagraphStyle(TextDirection.rtl),
+      ); // direction doesn't matter, text is just a zero width space
+      if (text?.style != null)
         builder.pushStyle(text.style.getTextStyle(textScaleFactor: textScaleFactor));
       builder.addText(_kZeroWidthSpace);
       _layoutTemplate = builder.build()
@@ -272,10 +320,14 @@ class TextPainter {
   /// Computes the visual position of the glyphs for painting the text.
   ///
   /// The text will layout with a width that's as close to its max intrinsic
-  /// width as possible while still being greater than or equal to minWidth and
-  /// less than or equal to maxWidth.
+  /// width as possible while still being greater than or equal to `minWidth` and
+  /// less than or equal to `maxWidth`.
+  ///
+  /// The [text] and [textDirection] properties must be non-null before this is
+  /// called.
   void layout({ double minWidth: 0.0, double maxWidth: double.INFINITY }) {
-    assert(_text != null);
+    assert(text != null, 'TextPainter.text must be set to a non-null value before using the TextPainter.');
+    assert(textDirection != null, 'TextPainter.textDirection must be set to a non-null value before using the TextPainter.');
     if (!_needsLayout && minWidth == _lastMinWidth && maxWidth == _lastMaxWidth)
       return;
     _needsLayout = false;
@@ -352,15 +404,34 @@ class TextPainter {
   }
 
   Offset get _emptyOffset {
-    // TODO(abarth): Handle the directionality of the text painter itself.
-    switch (textAlign ?? TextAlign.left) {
+    assert(!_needsLayout); // implies textDirection is non-null
+    assert(textAlign != null);
+    switch (textAlign) {
       case TextAlign.left:
-      case TextAlign.justify:
         return Offset.zero;
       case TextAlign.right:
         return new Offset(width, 0.0);
       case TextAlign.center:
         return new Offset(width / 2.0, 0.0);
+      case TextAlign.justify:
+      case TextAlign.start:
+        assert(textDirection != null);
+        switch (textDirection) {
+          case TextDirection.rtl:
+            return new Offset(width, 0.0);
+          case TextDirection.ltr:
+            return Offset.zero;
+        }
+        return null;
+      case TextAlign.end:
+        assert(textDirection != null);
+        switch (textDirection) {
+          case TextDirection.rtl:
+            return Offset.zero;
+          case TextDirection.ltr:
+            return new Offset(width, 0.0);
+        }
+        return null;
     }
     return null;
   }

packages/flutter/lib/src/painting/text_style.dart

@@ -369,6 +369,7 @@ class TextStyle extends Diagnosticable {
   /// specified and non-null, must be greater than zero.
   ui.ParagraphStyle getParagraphStyle({
       TextAlign textAlign,
+      TextDirection textDirection,
       double textScaleFactor: 1.0,
       String ellipsis,
       int maxLines,
@@ -377,6 +378,7 @@ class TextStyle extends Diagnosticable {
     assert(maxLines == null || maxLines > 0);
     return new ui.ParagraphStyle(
       textAlign: textAlign,
+      textDirection: textDirection,
       fontWeight: fontWeight,
       fontStyle: fontStyle,
       fontFamily: fontFamily,
@@ -418,7 +420,7 @@ class TextStyle extends Diagnosticable {
   bool operator ==(dynamic other) {
     if (identical(this, other))
       return true;
-    if (other is! TextStyle)
+    if (other.runtimeType != runtimeType)
       return false;
     final TextStyle typedOther = other;
     return inherit == typedOther.inherit &&

packages/flutter/lib/src/rendering/editable.dart

@@ -87,6 +87,10 @@ class TextSelectionPoint {
 class RenderEditable extends RenderBox {
   /// Creates a render object that implements the visual aspects of a text field.
   ///
+  /// The [textAlign] argument must not be null. It defaults to [TextAlign.start].
+  ///
+  /// The [textDirection] argument must not be null.
+  ///
   /// If [showCursor] is not specified, then it defaults to hiding the cursor.
   ///
   /// The [maxLines] property can be set to null to remove the restriction on
@@ -97,7 +101,8 @@ class RenderEditable extends RenderBox {
   /// ViewportOffset.zero] if you have no need for scrolling.
   RenderEditable({
     TextSpan text,
-    TextAlign textAlign,
+    @required TextDirection textDirection,
+    TextAlign textAlign: TextAlign.start,
     Color cursorColor,
     ValueNotifier<bool> showCursor,
     int maxLines: 1,
@@ -107,10 +112,17 @@ class RenderEditable extends RenderBox {
     @required ViewportOffset offset,
     this.onSelectionChanged,
     this.onCaretChanged,
-  }) : assert(maxLines == null || maxLines > 0),
+  }) : assert(textAlign != null),
+       assert(textDirection != null, 'RenderEditable created without a textDirection.'),
+       assert(maxLines == null || maxLines > 0),
        assert(textScaleFactor != null),
        assert(offset != null),
-       _textPainter = new TextPainter(text: text, textAlign: textAlign, textScaleFactor: textScaleFactor),
+       _textPainter = new TextPainter(
+         text: text,
+         textAlign: textAlign,
+         textDirection: textDirection,
+         textScaleFactor: textScaleFactor,
+       ),
        _cursorColor = cursorColor,
        _showCursor = showCursor ?? new ValueNotifier<bool>(false),
        _maxLines = maxLines,
@@ -146,7 +158,7 @@ class RenderEditable extends RenderBox {
     markNeedsLayout();
   }
 
-  /// The text to display
+  /// The text to display.
   TextSpan get text => _textPainter.text;
   final TextPainter _textPainter;
   set text(TextSpan value) {
@@ -157,14 +169,39 @@ class RenderEditable extends RenderBox {
   }
 
   /// How the text should be aligned horizontally.
+  ///
+  /// This must not be null.
   TextAlign get textAlign => _textPainter.textAlign;
   set textAlign(TextAlign value) {
+    assert(value != null);
     if (_textPainter.textAlign == value)
       return;
     _textPainter.textAlign = value;
     markNeedsPaint();
   }
 
+  /// The directionality of the text.
+  ///
+  /// This decides how the [TextAlign.start], [TextAlign.end], and
+  /// [TextAlign.justify] values of [textAlign] are interpreted.
+  ///
+  /// This is also used to disambiguate how to render bidirectional text. For
+  /// example, if the [text] is an English phrase followed by a Hebrew phrase,
+  /// in a [TextDirection.ltr] context the English phrase will be on the left
+  /// and the Hebrew phrase to its right, while in a [TextDirection.rtl]
+  /// context, the English phrase will be on the right and the Hebrow phrase on
+  /// its left.
+  ///
+  /// This must not be null.
+  TextDirection get textDirection => _textPainter.textDirection;
+  set textDirection(TextDirection value) {
+    assert(value != null);
+    if (_textPainter.textDirection == value)
+      return;
+    _textPainter.textDirection = value;
+    markNeedsTextLayout();
+  }
+
   /// The color to use when painting the cursor.
   Color get cursorColor => _cursorColor;
   Color _cursorColor;

packages/flutter/lib/src/rendering/flex.dart

@@ -993,12 +993,13 @@ class RenderFlex extends RenderBox with ContainerRenderObjectMixin<RenderBox, Fl
       }
       context.canvas.drawRect(markerRect, _debugMarkerPaint);
 
-      _debugMarkerLabel ??= new TextPainter();
-      _debugMarkerLabel.text = new TextSpan( // this is a no-op if the label hasn't changed
+      _debugMarkerLabel ??= new TextPainter()
+        ..textDirection = TextDirection.ltr; // This label is in English.
+      _debugMarkerLabel.text = new TextSpan( // This is a no-op if the label hasn't changed.
         text: label,
         style: _debugMarkerTextStyle,
       );
-      _debugMarkerLabel.layout(); // this is a no-op if the label hasn't changed
+      _debugMarkerLabel.layout(); // This is a no-op if the label hasn't changed.
 
       // TODO(ianh): RTL support
       switch (direction) {

packages/flutter/lib/src/rendering/object.dart

@@ -2867,11 +2867,11 @@ abstract class RenderObject extends AbstractNode with DiagnosticableTreeMixin im
   @override
   void debugFillProperties(DiagnosticPropertiesBuilder description) {
     description.add(new DiagnosticsProperty<dynamic>('creator', debugCreator, defaultValue: null));
-    description.add(new DiagnosticsProperty<ParentData>('parentData', parentData, tooltip: _debugCanParentUseSize == true ? "can use size" : null));
-    description.add(new DiagnosticsProperty<Constraints>('constraints', constraints));
+    description.add(new DiagnosticsProperty<ParentData>('parentData', parentData, tooltip: _debugCanParentUseSize == true ? 'can use size' : null, ifNull: 'MISSING'));
+    description.add(new DiagnosticsProperty<Constraints>('constraints', constraints, ifNull: 'MISSING'));
     // don't access it via the "layer" getter since that's only valid when we don't need paint
     description.add(new DiagnosticsProperty<OffsetLayer>('layer', _layer, defaultValue: null));
-    description.add(new DiagnosticsProperty<SemanticsNode>('_semantics', _semantics, defaultValue: null));
+    description.add(new DiagnosticsProperty<SemanticsNode>('semantics node', _semantics, defaultValue: null));
     description.add(new FlagProperty(
       'isBlockingSemanticsOfPreviouslyPaintedNodes',
       value: isBlockingSemanticsOfPreviouslyPaintedNodes,

packages/flutter/lib/src/rendering/paragraph.dart

@@ -32,19 +32,22 @@ const String _kEllipsis = '\u2026';
 class RenderParagraph extends RenderBox {
   /// Creates a paragraph render object.
   ///
-  /// The [text], [overflow], [softWrap], and [textScaleFactor] arguments must
-  /// not be null.
+  /// The [text], [textAlign], [textDirection], [overflow], [softWrap], and
+  /// [textScaleFactor] arguments must not be null.
   ///
   /// The [maxLines] property may be null (and indeed defaults to null), but if
   /// it is not null, it must be greater than zero.
   RenderParagraph(TextSpan text, {
-    TextAlign textAlign,
+    TextAlign textAlign: TextAlign.start,
+    @required TextDirection textDirection,
     bool softWrap: true,
     TextOverflow overflow: TextOverflow.clip,
     double textScaleFactor: 1.0,
     int maxLines,
   }) : assert(text != null),
        assert(text.debugAssertIsValid()),
+       assert(textAlign != null),
+       assert(textDirection != null),
        assert(softWrap != null),
        assert(overflow != null),
        assert(textScaleFactor != null),
@@ -54,6 +57,7 @@ class RenderParagraph extends RenderBox {
        _textPainter = new TextPainter(
          text: text,
          textAlign: textAlign,
+         textDirection: textDirection,
          textScaleFactor: textScaleFactor,
          maxLines: maxLines,
          ellipsis: overflow == TextOverflow.ellipsis ? _kEllipsis : null,
@@ -84,12 +88,35 @@ class RenderParagraph extends RenderBox {
   /// How the text should be aligned horizontally.
   TextAlign get textAlign => _textPainter.textAlign;
   set textAlign(TextAlign value) {
+    assert(value != null);
     if (_textPainter.textAlign == value)
       return;
     _textPainter.textAlign = value;
     markNeedsPaint();
   }
 
+  /// The directionality of the text.
+  ///
+  /// This decides how the [TextAlign.start], [TextAlign.end], and
+  /// [TextAlign.justify] values of [textAlign] are interpreted.
+  ///
+  /// This is also used to disambiguate how to render bidirectional text. For
+  /// example, if the [text] is an English phrase followed by a Hebrew phrase,
+  /// in a [TextDirection.ltr] context the English phrase will be on the left
+  /// and the Hebrew phrase to its right, while in a [TextDirection.rtl]
+  /// context, the English phrase will be on the right and the Hebrow phrase on
+  /// its left.
+  ///
+  /// This must not be null.
+  TextDirection get textDirection => _textPainter.textDirection;
+  set textDirection(TextDirection value) {
+    assert(value != null);
+    if (_textPainter.textDirection == value)
+      return;
+    _textPainter.textDirection = value;
+    markNeedsLayout();
+  }
+
   /// Whether the text should break at soft line breaks.
   ///
   /// If false, the glyphs in the text will be positioned as if there was
@@ -148,10 +175,8 @@ class RenderParagraph extends RenderBox {
   }
 
   void _layoutText({ double minWidth: 0.0, double maxWidth: double.INFINITY }) {
-    _textPainter.layout(
-        minWidth: minWidth,
-        maxWidth: _softWrap || _overflow == TextOverflow.ellipsis ? maxWidth : double.INFINITY
-    );
+    final bool widthMatters = softWrap || overflow == TextOverflow.ellipsis;
+    _textPainter.layout(minWidth: minWidth, maxWidth: widthMatters ? maxWidth : double.INFINITY);
   }
 
   void _layoutTextWithConstraints(BoxConstraints constraints) {
@@ -245,14 +270,24 @@ class RenderParagraph extends RenderBox {
           _overflowShader = null;
           break;
         case TextOverflow.fade:
+          assert(textDirection != null);
           final TextPainter fadeSizePainter = new TextPainter(
             text: new TextSpan(style: _textPainter.text.style, text: '\u2026'),
-            textScaleFactor: textScaleFactor
+            textDirection: textDirection,
+            textScaleFactor: textScaleFactor,
           )..layout();
           if (didOverflowWidth) {
-            final double fadeEnd = size.width;
-            final double fadeStart = fadeEnd - fadeSizePainter.width;
-            // TODO(abarth): This shader has an LTR bias.
+            double fadeEnd, fadeStart;
+            switch (textDirection) {
+              case TextDirection.rtl:
+                fadeEnd = 0.0;
+                fadeStart = fadeSizePainter.width;
+                break;
+              case TextDirection.ltr:
+                fadeEnd = size.width;
+                fadeStart = fadeEnd - fadeSizePainter.width;
+                break;
+            }
             _overflowShader = new ui.Gradient.linear(
               new Offset(fadeStart, 0.0),
               new Offset(fadeEnd, 0.0),
@@ -373,10 +408,22 @@ class RenderParagraph extends RenderBox {
 
   void _annotate(SemanticsNode node) {
     node.label = text.toPlainText();
+    node.textDirection = textDirection;
   }
 
   @override
   List<DiagnosticsNode> debugDescribeChildren() {
     return <DiagnosticsNode>[text.toDiagnosticsNode(name: 'text', style: DiagnosticsTreeStyle.transition)];
   }
+
+  @override
+  void debugFillProperties(DiagnosticPropertiesBuilder description) {
+    super.debugFillProperties(description);
+    description.add(new EnumProperty<TextAlign>('textAlign', textAlign));
+    description.add(new EnumProperty<TextDirection>('textDirection', textDirection));
+    description.add(new FlagProperty('softWrap', value: softWrap, ifTrue: 'wrapping at box width', ifFalse: 'no wrapping except at line break characters', showName: true));
+    description.add(new EnumProperty<TextOverflow>('overflow', overflow));
+    description.add(new DoubleProperty('textScaleFactor', textScaleFactor, defaultValue: 1.0));
+    description.add(new IntProperty('maxLines', maxLines, ifNull: 'unlimited'));
+  }
 }

packages/flutter/lib/src/rendering/proxy_box.dart

@@ -3114,17 +3114,21 @@ class RenderSemanticsAnnotations extends RenderProxyBox {
   /// Creates a render object that attaches a semantic annotation.
   ///
   /// The [container] argument must not be null.
+  ///
+  /// If the [label] is not null, the [textDirection] must also not be null.
   RenderSemanticsAnnotations({
     RenderBox child,
     bool container: false,
     bool checked,
     bool selected,
     String label,
+    TextDirection textDirection,
   }) : assert(container != null),
        _container = container,
        _checked = checked,
        _selected = selected,
        _label = label,
+       _textDirection = textDirection,
        super(child);
 
   /// If 'container' is true, this RenderObject will introduce a new
@@ -3182,11 +3186,24 @@ class RenderSemanticsAnnotations extends RenderProxyBox {
     markNeedsSemanticsUpdate(onlyLocalUpdates: (value != null) == hadValue);
   }
 
+  /// If non-null, sets the [SemanticsNode.textDirection] semantic to the given value.
+  ///
+  /// This must not be null if [label] is not null.
+  TextDirection get textDirection => _textDirection;
+  TextDirection _textDirection;
+  set textDirection(TextDirection value) {
+    if (textDirection == value)
+      return;
+    final bool hadValue = textDirection != null;
+    _textDirection = value;
+    markNeedsSemanticsUpdate(onlyLocalUpdates: (value != null) == hadValue);
+  }
+
   @override
   bool get isSemanticBoundary => container;
 
   @override
-  SemanticsAnnotator get semanticsAnnotator => checked != null || selected != null || label != null ? _annotate : null;
+  SemanticsAnnotator get semanticsAnnotator => checked != null || selected != null || label != null || textDirection != null ? _annotate : null;
 
   void _annotate(SemanticsNode node) {
     if (checked != null) {
@@ -3198,6 +3215,8 @@ class RenderSemanticsAnnotations extends RenderProxyBox {
       node.isSelected = selected;
     if (label != null)
       node.label = label;
+    if (textDirection != null)
+      node.textDirection = textDirection;
   }
 }
 

packages/flutter/lib/src/rendering/semantics.dart

@@ -92,16 +92,20 @@ class SemanticsData {
   /// Creates a semantics data object.
   ///
   /// The [flags], [actions], [label], and [Rect] arguments must not be null.
+  ///
+  /// If [label] is not empty, then [textDirection] must also not be null.
   const SemanticsData({
     @required this.flags,
     @required this.actions,
     @required this.label,
+    @required this.textDirection,
     @required this.rect,
     @required this.tags,
-    this.transform
+    this.transform,
   }) : assert(flags != null),
        assert(actions != null),
        assert(label != null),
+       assert(label == '' || textDirection != null, 'A SemanticsData object with label "$label" had a null textDirection.'),
        assert(rect != null),
        assert(tags != null);
 
@@ -112,8 +116,13 @@ class SemanticsData {
   final int actions;
 
   /// A textual description of this node.
+  ///
+  /// The text's reading direction is given by [textDirection].
   final String label;
 
+  /// The reading direction for the text in [label].
+  final TextDirection textDirection;
+
   /// The bounding box for this node in its coordinate system.
   final Rect rect;
 
@@ -149,6 +158,8 @@ class SemanticsData {
     }
     if (label.isNotEmpty)
       buffer.write('; "$label"');
+    if (textDirection != null)
+      buffer.write('; $textDirection');
     buffer.write(')');
     return buffer.toString();
   }
@@ -161,13 +172,14 @@ class SemanticsData {
     return typedOther.flags == flags
         && typedOther.actions == actions
         && typedOther.label == label
+        && typedOther.textDirection == textDirection
         && typedOther.rect == rect
         && setEquals(typedOther.tags, tags)
         && typedOther.transform == transform;
   }
 
   @override
-  int get hashCode => hashValues(flags, actions, label, rect, tags, transform);
+  int get hashCode => hashValues(flags, actions, label, textDirection, rect, tags, transform);
 }
 
 /// A node that represents some semantic data.
@@ -342,6 +354,8 @@ class SemanticsNode extends AbstractNode {
   set isSelected(bool value) => _setFlag(SemanticsFlags.isSelected, value);
 
   /// A textual description of this node.
+  ///
+  /// The text's reading direction is given by [textDirection].
   String get label => _label;
   String _label = '';
   set label(String value) {
@@ -352,6 +366,17 @@ class SemanticsNode extends AbstractNode {
     }
   }
 
+  /// The reading direction for the text in [label].
+  TextDirection get textDirection => _textDirection;
+  TextDirection _textDirection;
+  set textDirection(TextDirection value) {
+    assert(value != null);
+    if (_textDirection != value) {
+      _textDirection = value;
+      _markDirty();
+    }
+  }
+
   final Set<SemanticsTag> _tags = new Set<SemanticsTag>();
 
   /// Tags the [SemanticsNode] with [tag].
@@ -385,6 +410,7 @@ class SemanticsNode extends AbstractNode {
     if (hadInheritedMergeAllDescendantsIntoThisNode)
       _inheritedMergeAllDescendantsIntoThisNodeValue = true;
     _label = '';
+    _textDirection = null;
     _tags.clear();
     _markDirty();
   }
@@ -598,18 +624,31 @@ class SemanticsNode extends AbstractNode {
     int flags = _flags;
     int actions = _actions;
     String label = _label;
+    TextDirection textDirection = _textDirection;
     final Set<SemanticsTag> tags = new Set<SemanticsTag>.from(_tags);
 
     if (mergeAllDescendantsIntoThisNode) {
       _visitDescendants((SemanticsNode node) {
         flags |= node._flags;
         actions |= node._actions;
+        textDirection ??= node._textDirection;
         tags.addAll(node._tags);
         if (node.label.isNotEmpty) {
+          String nestedLabel = node.label;
+          if (textDirection != node.textDirection && node.textDirection != null) {
+            switch (node.textDirection) {
+              case TextDirection.rtl:
+                nestedLabel = '${Unicode.RLE}$nestedLabel${Unicode.PDF}';
+                break;
+              case TextDirection.ltr:
+                nestedLabel = '${Unicode.LRE}$nestedLabel${Unicode.PDF}';
+                break;
+            }
+          }
           if (label.isEmpty)
-            label = node.label;
+            label = nestedLabel;
           else
-            label = '$label\n${node.label}';
+            label = '$label\n$nestedLabel';
         }
         return true;
       });
@@ -619,6 +658,7 @@ class SemanticsNode extends AbstractNode {
       flags: flags,
       actions: actions,
       label: label,
+      textDirection: textDirection,
       rect: rect,
       transform: transform,
       tags: tags,
@@ -650,6 +690,7 @@ class SemanticsNode extends AbstractNode {
       actions: data.actions,
       rect: data.rect,
       label: data.label,
+      textDirection: data.textDirection,
       transform: data.transform?.storage ?? _kIdentityTransform,
       children: children,
     );
@@ -696,6 +737,8 @@ class SemanticsNode extends AbstractNode {
       buffer.write('; selected');
     if (label.isNotEmpty)
       buffer.write('; "$label"');
+    if (textDirection != null)
+      buffer.write('; $textDirection');
     buffer.write(')');
     return buffer.toString();
   }

packages/flutter/lib/src/rendering/sliver_grid.dart

@@ -553,7 +553,8 @@ class RenderSliverGrid extends RenderSliverMultiBoxAdaptor {
     for (int index = indexOf(firstChild) - 1; index >= firstIndex; --index) {
       final SliverGridGeometry gridGeometry = layout.getGeometryForChildIndex(index);
       final RenderBox child = insertAndLayoutLeadingChild(
-          gridGeometry.getBoxConstraints(constraints));
+        gridGeometry.getBoxConstraints(constraints),
+      );
       final SliverGridParentData childParentData = child.parentData;
       childParentData.layoutOffset = gridGeometry.scrollOffset;
       childParentData.crossAxisOffset = gridGeometry.crossAxisOffset;

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

@@ -41,13 +41,15 @@ enum BannerLocation {
 class BannerPainter extends CustomPainter {
   /// Creates a banner painter.
   ///
-  /// The [message] and [location] arguments must not be null.
+  /// The [message], [textDirection], and [location] arguments must not be null.
   BannerPainter({
     @required this.message,
+    @required this.textDirection,
     @required this.location,
     this.color: _kColor,
     this.textStyle: _kTextStyle,
   }) : assert(message != null),
+       assert(textDirection != null),
        assert(location != null),
        assert(color != null),
        assert(textStyle != null);
@@ -55,6 +57,16 @@ class BannerPainter extends CustomPainter {
   /// The message to show in the banner.
   final String message;
 
+  /// The directionality of the text.
+  ///
+  /// This is used to disambiguate how to render bidirectional text. For
+  /// example, if the message is an English phrase followed by a Hebrew phrase,
+  /// in a [TextDirection.ltr] context the English phrase will be on the left
+  /// and the Hebrew phrase to its right, while in a [TextDirection.rtl]
+  /// context, the English phrase will be on the right and the Hebrow phrase on
+  /// its left.
+  final TextDirection textDirection;
+
   /// Where to show the banner (e.g., the upper right corder).
   final BannerLocation location;
 
@@ -82,6 +94,7 @@ class BannerPainter extends CustomPainter {
     _textPainter = new TextPainter(
       text: new TextSpan(style: textStyle, text: message),
       textAlign: TextAlign.center,
+      textDirection: textDirection,
     );
     _prepared = true;
   }
@@ -169,6 +182,7 @@ class Banner extends StatelessWidget {
     Key key,
     this.child,
     @required this.message,
+    this.textDirection,
     @required this.location,
     this.color: _kColor,
     this.textStyle: _kTextStyle,
@@ -184,6 +198,18 @@ class Banner extends StatelessWidget {
   /// The message to show in the banner.
   final String message;
 
+  /// The directionality of the text.
+  ///
+  /// This is used to disambiguate how to render bidirectional text. For
+  /// example, if the message is an English phrase followed by a Hebrew phrase,
+  /// in a [TextDirection.ltr] context the English phrase will be on the left
+  /// and the Hebrew phrase to its right, while in a [TextDirection.rtl]
+  /// context, the English phrase will be on the right and the Hebrow phrase on
+  /// its left.
+  ///
+  /// Defaults to the ambient [Directionality], if any.
+  final TextDirection textDirection;
+
   /// Where to show the banner (e.g., the upper right corder).
   final BannerLocation location;
 
@@ -198,6 +224,7 @@ class Banner extends StatelessWidget {
     return new CustomPaint(
       foregroundPainter: new BannerPainter(
         message: message,
+        textDirection: textDirection ?? Directionality.of(context),
         location: location,
         color: color,
         textStyle: textStyle,
@@ -210,6 +237,7 @@ class Banner extends StatelessWidget {
   void debugFillProperties(DiagnosticPropertiesBuilder description) {
     super.debugFillProperties(description);
     description.add(new StringProperty('message', message, showName: false));
+    description.add(new EnumProperty<TextDirection>('textDirection', textDirection, defaultValue: null));
     description.add(new EnumProperty<BannerLocation>('location', location));
     description.add(new DiagnosticsProperty<Color>('color', color, showName: false));
     textStyle?.debugFillProperties(description, prefix: 'text ');
@@ -236,7 +264,9 @@ class CheckedModeBanner extends StatelessWidget {
       result = new Banner(
         child: result,
         message: 'SLOW MODE',
-        location: BannerLocation.topRight);
+        textDirection: TextDirection.ltr,
+        location: BannerLocation.topRight,
+      );
       return true;
     });
     return result;

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

@@ -3704,20 +3704,25 @@ class Flow extends MultiChildRenderObjectWidget {
 class RichText extends LeafRenderObjectWidget {
   /// Creates a paragraph of rich text.
   ///
-  /// The [text], [softWrap], [overflow], nad [textScaleFactor] arguments must
-  /// not be null.
+  /// The [text], [textAlign], [softWrap], [overflow], nad [textScaleFactor]
+  /// arguments must not be null.
   ///
   /// The [maxLines] property may be null (and indeed defaults to null), but if
   /// it is not null, it must be greater than zero.
+  ///
+  /// The [textDirection], if null, defaults to the ambient [Directionality],
+  /// which in that case must not be null.
   const RichText({
     Key key,
     @required this.text,
-    this.textAlign,
+    this.textAlign: TextAlign.start,
+    this.textDirection,
     this.softWrap: true,
     this.overflow: TextOverflow.clip,
     this.textScaleFactor: 1.0,
     this.maxLines,
   }) : assert(text != null),
+       assert(textAlign != null),
        assert(softWrap != null),
        assert(overflow != null),
        assert(textScaleFactor != null),
@@ -3730,6 +3735,22 @@ class RichText extends LeafRenderObjectWidget {
   /// How the text should be aligned horizontally.
   final TextAlign textAlign;
 
+  /// The directionality of the text.
+  ///
+  /// This decides how [textAlign] values like [TextAlign.start] and
+  /// [TextAlign.end] are interpreted.
+  ///
+  /// This is also used to disambiguate how to render bidirectional text. For
+  /// example, if the [text] is an English phrase followed by a Hebrew phrase,
+  /// in a [TextDirection.ltr] context the English phrase will be on the left
+  /// and the Hebrew phrase to its right, while in a [TextDirection.rtl]
+  /// context, the English phrase will be on the right and the Hebrow phrase on
+  /// its left.
+  ///
+  /// Defaults to the ambient [Directionality], if any. If there is no ambient
+  /// [Directionality], then this must not be null.
+  final TextDirection textDirection;
+
   /// Whether the text should break at soft line breaks.
   ///
   /// If false, the glyphs in the text will be positioned as if there was unlimited horizontal space.
@@ -3754,8 +3775,11 @@ class RichText extends LeafRenderObjectWidget {
 
   @override
   RenderParagraph createRenderObject(BuildContext context) {
+    final TextDirection direction = textDirection ?? Directionality.of(context);
+    assert(direction != null, 'A RichText was created with no textDirection and no ambient Directionality widget.');
     return new RenderParagraph(text,
       textAlign: textAlign,
+      textDirection: direction,
       softWrap: softWrap,
       overflow: overflow,
       textScaleFactor: textScaleFactor,
@@ -3768,6 +3792,7 @@ class RichText extends LeafRenderObjectWidget {
     renderObject
       ..text = text
       ..textAlign = textAlign
+      ..textDirection = textDirection ?? Directionality.of(context)
       ..softWrap = softWrap
       ..overflow = overflow
       ..textScaleFactor = textScaleFactor
@@ -4289,6 +4314,7 @@ class Semantics extends SingleChildRenderObjectWidget {
     this.checked,
     this.selected,
     this.label,
+    this.textDirection,
   }) : assert(container != null),
        super(key: key, child: child);
 
@@ -4317,8 +4343,20 @@ class Semantics extends SingleChildRenderObjectWidget {
   final bool selected;
 
   /// Provides a textual description of the widget.
+  ///
+  /// If a label is provided, there must either by an ambient [Directionality]
+  /// or an explicit [textDirection] should be provided.
   final String label;
 
+  /// The reading direction of the [label].
+  ///
+  /// Defaults to the ambient [Directionality].
+  final TextDirection textDirection;
+
+  TextDirection _getTextDirection(BuildContext context) {
+    return textDirection ?? (label != null ? Directionality.of(context) : null);
+  }
+
   @override
   RenderSemanticsAnnotations createRenderObject(BuildContext context) {
     return new RenderSemanticsAnnotations(
@@ -4326,6 +4364,7 @@ class Semantics extends SingleChildRenderObjectWidget {
       checked: checked,
       selected: selected,
       label: label,
+      textDirection: _getTextDirection(context),
     );
   }
 
@@ -4335,7 +4374,8 @@ class Semantics extends SingleChildRenderObjectWidget {
       ..container = container
       ..checked = checked
       ..selected = selected
-      ..label = label;
+      ..label = label
+      ..textDirection = _getTextDirection(context);
   }
 
   @override
@@ -4344,7 +4384,8 @@ class Semantics extends SingleChildRenderObjectWidget {
     description.add(new DiagnosticsProperty<bool>('container', container));
     description.add(new DiagnosticsProperty<bool>('checked', checked, defaultValue: null));
     description.add(new DiagnosticsProperty<bool>('selected', selected, defaultValue: null));
-    description.add(new StringProperty('label', label));
+    description.add(new StringProperty('label', label, defaultValue: ''));
+    description.add(new EnumProperty<TextDirection>('textDirection', textDirection, defaultValue: null));
   }
 }
 

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

@@ -144,8 +144,8 @@ class EditableText extends StatefulWidget {
   /// the number of lines. By default, it is 1, meaning this is a single-line
   /// text field. If it is not null, it must be greater than zero.
   ///
-  /// The [controller], [focusNode], [style], and [cursorColor] arguments must
-  /// not be null.
+  /// The [controller], [focusNode], [style], [cursorColor], and [textAlign]
+  /// arguments must not be null.
   EditableText({
     Key key,
     @required this.controller,
@@ -154,7 +154,8 @@ class EditableText extends StatefulWidget {
     this.autocorrect: true,
     @required this.style,
     @required this.cursorColor,
-    this.textAlign,
+    this.textAlign: TextAlign.start,
+    this.textDirection,
     this.textScaleFactor,
     this.maxLines: 1,
     this.autofocus: false,
@@ -171,6 +172,7 @@ class EditableText extends StatefulWidget {
        assert(autocorrect != null),
        assert(style != null),
        assert(cursorColor != null),
+       assert(textAlign != null),
        assert(maxLines == null || maxLines > 0),
        assert(autofocus != null),
        inputFormatters = maxLines == 1
@@ -201,8 +203,25 @@ class EditableText extends StatefulWidget {
   final TextStyle style;
 
   /// How the text should be aligned horizontally.
+  ///
+  /// Defaults to [TextAlign.start].
   final TextAlign textAlign;
 
+  /// The directionality of the text.
+  ///
+  /// This decides how [textAlign] values like [TextAlign.start] and
+  /// [TextAlign.end] are interpreted.
+  ///
+  /// This is also used to disambiguate how to render bidirectional text. For
+  /// example, if the text is an English phrase followed by a Hebrew phrase,
+  /// in a [TextDirection.ltr] context the English phrase will be on the left
+  /// and the Hebrew phrase to its right, while in a [TextDirection.rtl]
+  /// context, the English phrase will be on the right and the Hebrow phrase on
+  /// its left.
+  ///
+  /// Defaults to the ambient [Directionality], if any.
+  final TextDirection textDirection;
+
   /// The number of font pixels for each logical pixel.
   ///
   /// For example, if the text scale factor is 1.5, text will be 50% larger than
@@ -266,6 +285,7 @@ class EditableText extends StatefulWidget {
     description.add(new DiagnosticsProperty<bool>('autocorrect', autocorrect, defaultValue: true));
     style?.debugFillProperties(description);
     description.add(new EnumProperty<TextAlign>('textAlign', textAlign, defaultValue: null));
+    description.add(new EnumProperty<TextDirection>('textDirection', textDirection, defaultValue: null));
     description.add(new DoubleProperty('textScaleFactor', textScaleFactor, defaultValue: null));
     description.add(new IntProperty('maxLines', maxLines, defaultValue: 1));
     description.add(new DiagnosticsProperty<bool>('autofocus', autofocus, defaultValue: false));
@@ -575,6 +595,12 @@ class EditableTextState extends State<EditableText> with AutomaticKeepAliveClien
     updateKeepAlive();
   }
 
+  TextDirection get _textDirection {
+    final TextDirection result = widget.textDirection ?? Directionality.of(context);
+    assert(result != null, '$runtimeType created without a textDirection and with no ambient Directionality.');
+    return result;
+  }
+
   @override
   Widget build(BuildContext context) {
     FocusScope.of(context).reparentIfNeeded(widget.focusNode);
@@ -595,6 +621,7 @@ class EditableTextState extends State<EditableText> with AutomaticKeepAliveClien
             selectionColor: widget.selectionColor,
             textScaleFactor: widget.textScaleFactor ?? MediaQuery.of(context, nullOk: true)?.textScaleFactor ?? 1.0,
             textAlign: widget.textAlign,
+            textDirection: _textDirection,
             obscureText: widget.obscureText,
             obscureShowCharacterAtIndex: _obscureShowCharTicksPending > 0 ? _obscureLatestCharIndex : null,
             autocorrect: widget.autocorrect,
@@ -619,13 +646,15 @@ class _Editable extends LeafRenderObjectWidget {
     this.selectionColor,
     this.textScaleFactor,
     this.textAlign,
+    @required this.textDirection,
     this.obscureText,
     this.obscureShowCharacterAtIndex,
     this.autocorrect,
     this.offset,
     this.onSelectionChanged,
     this.onCaretChanged,
-  }) : super(key: key);
+  }) : assert(textDirection != null),
+       super(key: key);
 
   final TextEditingValue value;
   final TextStyle style;
@@ -635,6 +664,7 @@ class _Editable extends LeafRenderObjectWidget {
   final Color selectionColor;
   final double textScaleFactor;
   final TextAlign textAlign;
+  final TextDirection textDirection;
   final bool obscureText;
   final int obscureShowCharacterAtIndex;
   final bool autocorrect;
@@ -652,6 +682,7 @@ class _Editable extends LeafRenderObjectWidget {
       selectionColor: selectionColor,
       textScaleFactor: textScaleFactor,
       textAlign: textAlign,
+      textDirection: textDirection,
       selection: value.selection,
       offset: offset,
       onSelectionChanged: onSelectionChanged,
@@ -669,6 +700,7 @@ class _Editable extends LeafRenderObjectWidget {
       ..selectionColor = selectionColor
       ..textScaleFactor = textScaleFactor
       ..textAlign = textAlign
+      ..textDirection = textDirection
       ..selection = value.selection
       ..offset = offset
       ..onSelectionChanged = onSelectionChanged

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

@@ -17,6 +17,10 @@ import 'icon_theme_data.dart';
 /// Icons are not interactive. For an interactive icon, consider material's
 /// [IconButton].
 ///
+/// There must be an ambient [Directionality] widget when using [Icon].
+/// Typically this is introduced automatically by the [WidgetsApp] or
+/// [MaterialApp].
+///
 /// See also:
 ///
 ///  * [IconButton], for interactive icons.
@@ -80,6 +84,9 @@ class Icon extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
+    final TextDirection textDirection = Directionality.of(context);
+    assert(textDirection != null, 'Icon widgets required an ambient Directionality.');
+
     final IconThemeData iconTheme = IconTheme.of(context);
 
     final double iconSize = size ?? iconTheme.size;
@@ -98,18 +105,19 @@ class Icon extends StatelessWidget {
         height: iconSize,
         child: new Center(
           child: new RichText(
+            textDirection: textDirection, // Since we already fetched it for the assert...
             text: new TextSpan(
               text: new String.fromCharCode(icon.codePoint),
               style: new TextStyle(
                 inherit: false,
                 color: iconColor,
                 fontSize: iconSize,
-                fontFamily: icon.fontFamily
-              )
-            )
-          )
-        )
-      )
+                fontFamily: icon.fontFamily,
+              ),
+            ),
+          ),
+        ),
+      ),
     );
   }
 

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

@@ -228,15 +228,29 @@ String _getMessage(SemanticsNode node) {
   if (isAdjustable)
     annotations.add('adjustable');
 
-  String message;
-  if (annotations.isEmpty) {
   assert(data.label != null);
-    message = data.label;
-  } else {
+  String message;
   if (data.label.isEmpty) {
     message = annotations.join('; ');
   } else {
-      message = '${data.label} (${annotations.join('; ')})';
+    String label;
+    if (data.textDirection == null) {
+      label = '${Unicode.FSI}${data.label}${Unicode.PDI}';
+      annotations.insert(0, 'MISSING TEXT DIRECTION');
+    } else {
+      switch (data.textDirection) {
+        case TextDirection.rtl:
+          label = '${Unicode.RLI}${data.label}${Unicode.PDF}';
+          break;
+        case TextDirection.ltr:
+          label = data.label;
+          break;
+      }
+    }
+    if (annotations.isEmpty) {
+      message = label;
+    } else {
+      message = '$label (${annotations.join('; ')})';
     }
   }
 
@@ -257,7 +271,11 @@ void _paintMessage(Canvas canvas, SemanticsNode node) {
   canvas.save();
   canvas.clipRect(rect);
   final TextPainter textPainter = new TextPainter()
-    ..text = new TextSpan(style: _messageStyle, text: message)
+    ..text = new TextSpan(
+      style: _messageStyle,
+      text: message,
+    )
+    ..textDirection = TextDirection.ltr // _getMessage always returns LTR text, even if node.label is RTL
     ..textAlign = TextAlign.center
     ..layout(maxWidth: rect.width);
 

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

@@ -200,6 +200,7 @@ class Text extends StatelessWidget {
     Key key,
     this.style,
     this.textAlign,
+    this.textDirection,
     this.softWrap,
     this.overflow,
     this.textScaleFactor,
@@ -220,6 +221,21 @@ class Text extends StatelessWidget {
   /// How the text should be aligned horizontally.
   final TextAlign textAlign;
 
+  /// The directionality of the text.
+  ///
+  /// This decides how [textAlign] values like [TextAlign.start] and
+  /// [TextAlign.end] are interpreted.
+  ///
+  /// This is also used to disambiguate how to render bidirectional text. For
+  /// example, if the [data] is an English phrase followed by a Hebrew phrase,
+  /// in a [TextDirection.ltr] context the English phrase will be on the left
+  /// and the Hebrew phrase to its right, while in a [TextDirection.rtl]
+  /// context, the English phrase will be on the right and the Hebrow phrase on
+  /// its left.
+  ///
+  /// Defaults to the ambient [Directionality], if any.
+  final TextDirection textDirection;
+
   /// Whether the text should break at soft line breaks.
   ///
   /// If false, the glyphs in the text will be positioned as if there was unlimited horizontal space.
@@ -257,7 +273,8 @@ class Text extends StatelessWidget {
     if (style == null || style.inherit)
       effectiveTextStyle = defaultTextStyle.style.merge(style);
     return new RichText(
-      textAlign: textAlign ?? defaultTextStyle.textAlign,
+      textAlign: textAlign ?? defaultTextStyle.textAlign ?? TextAlign.start,
+      textDirection: textDirection, // RichText uses Directionality.of to obtain a default if this is null.
       softWrap: softWrap ?? defaultTextStyle.softWrap,
       overflow: overflow ?? defaultTextStyle.overflow,
       textScaleFactor: textScaleFactor ?? MediaQuery.of(context, nullOk: true)?.textScaleFactor ?? 1.0,

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

@@ -361,12 +361,14 @@ class _InspectorOverlayRenderState {
     @required this.selected,
     @required this.candidates,
     @required this.tooltip,
+    @required this.textDirection,
   });
 
   final Rect overlayRect;
   final _TransformedRect selected;
   final List<_TransformedRect> candidates;
   final String tooltip;
+  final TextDirection textDirection;
 
   @override
   bool operator ==(dynamic other) {
@@ -447,6 +449,7 @@ class _InspectorOverlayLayer extends Layer {
       overlayRect: overlayRect,
       selected: new _TransformedRect(selected),
       tooltip: selected.toString(),
+      textDirection: TextDirection.ltr,
       candidates: candidates,
     );
 
@@ -497,15 +500,22 @@ class _InspectorOverlayLayer extends Layer {
     final double offsetFromWidget = 9.0;
     final double verticalOffset = (targetRect.height) / 2 + offsetFromWidget;
 
-    _paintDescription(canvas, state.tooltip, target, verticalOffset, size, targetRect);
+    _paintDescription(canvas, state.tooltip, state.textDirection, target, verticalOffset, size, targetRect);
 
     // TODO(jacobr): provide an option to perform a debug paint of just the
     // selected widget.
     return recorder.endRecording();
   }
 
-  void _paintDescription(Canvas canvas, String message, Offset target,
-      double verticalOffset, Size size, Rect targetRect) {
+  void _paintDescription(
+    Canvas canvas,
+    String message,
+    TextDirection textDirection,
+    Offset target,
+    double verticalOffset,
+    Size size,
+    Rect targetRect,
+  ) {
     canvas.save();
     final double maxWidth = size.width - 2 * (_kScreenEdgeMargin + _kTooltipPadding);
     if (_textPainter == null || _textPainter.text.text != message || _textPainterMaxWidth != maxWidth) {
@@ -514,6 +524,7 @@ class _InspectorOverlayLayer extends Layer {
         ..maxLines = _kMaxTooltipLines
         ..ellipsis = '...'
         ..text = new TextSpan(style: _messageStyle, text: message)
+        ..textDirection = textDirection
         ..layout(maxWidth: maxWidth);
     }
 

packages/flutter/test/cupertino/button_test.dart

@@ -14,7 +14,7 @@ const TextStyle testStyle = const TextStyle(
 void main() {
   testWidgets('Default layout minimum size', (WidgetTester tester) async {
     await tester.pumpWidget(
-      const Center(child: const CupertinoButton(
+      boilerplate(child: const CupertinoButton(
         child: const Text('X', style: testStyle),
         onPressed: null,
       ))
@@ -30,7 +30,7 @@ void main() {
   testWidgets('Minimum size parameter', (WidgetTester tester) async {
     final double minSize = 60.0;
     await tester.pumpWidget(
-      new Center(child: new CupertinoButton(
+      boilerplate(child: new CupertinoButton(
         child: const Text('X', style: testStyle),
         onPressed: null,
         minSize: minSize,
@@ -46,7 +46,7 @@ void main() {
 
   testWidgets('Size grows with text', (WidgetTester tester) async {
     await tester.pumpWidget(
-      const Center(child: const CupertinoButton(
+      boilerplate(child: const CupertinoButton(
         child: const Text('XXXX', style: testStyle),
         onPressed: null,
       ))
@@ -60,7 +60,7 @@ void main() {
   });
 
   testWidgets('Button with background is wider', (WidgetTester tester) async {
-    await tester.pumpWidget(const Center(child: const CupertinoButton(
+    await tester.pumpWidget(boilerplate(child: const CupertinoButton(
       child: const Text('X', style: testStyle),
       onPressed: null,
       color: const Color(0xFFFFFFFF),
@@ -74,7 +74,7 @@ void main() {
   });
 
   testWidgets('Custom padding', (WidgetTester tester) async {
-    await tester.pumpWidget(const Center(child: const CupertinoButton(
+    await tester.pumpWidget(boilerplate(child: const CupertinoButton(
       child: const Text(' ', style: testStyle),
       onPressed: null,
       padding: const EdgeInsets.all(100.0),
@@ -91,7 +91,7 @@ void main() {
     await tester.pumpWidget(
       new StatefulBuilder(
         builder: (BuildContext context, StateSetter setState) {
-          return new Center(
+          return boilerplate(
             child: new CupertinoButton(
               child: const Text('Tap me'),
               onPressed: () {
@@ -115,7 +115,7 @@ void main() {
   });
 
   testWidgets('Disabled button doesn\'t animate', (WidgetTester tester) async {
-    await tester.pumpWidget(const Center(child: const CupertinoButton(
+    await tester.pumpWidget(boilerplate(child: const CupertinoButton(
       child: const Text('Tap me'),
       onPressed: null,
     )));
@@ -126,7 +126,7 @@ void main() {
   });
 
   testWidgets('pressedOpacity defaults to 0.1', (WidgetTester tester) async {
-    await tester.pumpWidget(new Center(child: new CupertinoButton(
+    await tester.pumpWidget(boilerplate(child: new CupertinoButton(
       child: const Text('Tap me'),
       onPressed: () { },
     )));
@@ -146,7 +146,7 @@ void main() {
 
   testWidgets('pressedOpacity parameter', (WidgetTester tester) async {
     final double pressedOpacity = 0.5;
-    await tester.pumpWidget(new Center(child: new CupertinoButton(
+    await tester.pumpWidget(boilerplate(child: new CupertinoButton(
       pressedOpacity: pressedOpacity,
       child: const Text('Tap me'),
       onPressed: () { },
@@ -165,3 +165,10 @@ void main() {
     expect(opacity.opacity, pressedOpacity);
   });
 }
+
+Widget boilerplate({ Widget child }) {
+  return new Directionality(
+    textDirection: TextDirection.ltr,
+    child: new Center(child: child),
+  );
+}

packages/flutter/test/cupertino/dialog_test.dart

@@ -64,10 +64,10 @@ void main() {
   });
 
   testWidgets('Dialog destructive action styles', (WidgetTester tester) async {
-    await tester.pumpWidget(const CupertinoDialogAction(
+    await tester.pumpWidget(boilerplate(const CupertinoDialogAction(
       isDestructiveAction: true,
       child: const Text('Ok'),
-    ));
+    )));
 
     final DefaultTextStyle widget = tester.widget(find.byType(DefaultTextStyle));
 
@@ -76,10 +76,10 @@ void main() {
   });
 
   testWidgets('Dialog default action styles', (WidgetTester tester) async {
-    await tester.pumpWidget(const CupertinoDialogAction(
+    await tester.pumpWidget(boilerplate(const CupertinoDialogAction(
       isDefaultAction: true,
       child: const Text('Ok'),
-    ));
+    )));
 
     final DefaultTextStyle widget = tester.widget(find.byType(DefaultTextStyle));
 
@@ -87,11 +87,11 @@ void main() {
   });
 
   testWidgets('Default and destructive style', (WidgetTester tester) async {
-    await tester.pumpWidget(const CupertinoDialogAction(
+    await tester.pumpWidget(boilerplate(const CupertinoDialogAction(
       isDefaultAction: true,
       isDestructiveAction: true,
       child: const Text('Ok'),
-    ));
+    )));
 
     final DefaultTextStyle widget = tester.widget(find.byType(DefaultTextStyle));
 
@@ -99,3 +99,10 @@ void main() {
     expect(widget.style.color.red, greaterThan(widget.style.color.blue));
   });
 }
+
+Widget boilerplate(Widget child) {
+  return new Directionality(
+    textDirection: TextDirection.ltr,
+    child: child,
+  );
+}

packages/flutter/test/material/buttons_test.dart

@@ -14,14 +14,17 @@ void main() {
   testWidgets('Does FlatButton contribute semantics', (WidgetTester tester) async {
     final SemanticsTester semantics = new SemanticsTester(tester);
     await tester.pumpWidget(
-      new Material(
+      new Directionality(
+        textDirection: TextDirection.ltr,
+        child: new Material(
           child: new Center(
             child: new FlatButton(
               onPressed: () { },
               child: const Text('ABC')
-          )
-        )
-      )
+            ),
+          ),
+        ),
+      ),
     );
 
     expect(semantics, hasSemantics(
@@ -58,10 +61,13 @@ void main() {
     );
 
     await tester.pumpWidget(
-      new Theme(
+      new Directionality(
+        textDirection: TextDirection.ltr,
+        child: new Theme(
           data: new ThemeData(),
           child: buttonWidget,
         ),
+      ),
     );
 
     final Offset center = tester.getCenter(find.byType(MaterialButton));
@@ -88,13 +94,16 @@ void main() {
     );
 
     await tester.pumpWidget(
-      new Theme(
+      new Directionality(
+        textDirection: TextDirection.ltr,
+        child: new Theme(
           data: new ThemeData(
             highlightColor: themeHighlightColor1,
             splashColor: themeSplashColor1,
           ),
           child: buttonWidget,
         ),
+      ),
     );
 
     expect(
@@ -108,13 +117,16 @@ void main() {
     final Color themeHighlightColor2 = const Color(0xFF002200);
 
     await tester.pumpWidget(
-      new Theme(
+      new Directionality(
+        textDirection: TextDirection.ltr,
+        child: new Theme(
           data: new ThemeData(
             highlightColor: themeHighlightColor2,
             splashColor: themeSplashColor2,
           ),
           child: buttonWidget, // same widget, so does not get updated because of us
         ),
+      ),
     );
 
     expect(

packages/flutter/test/material/circle_avatar_test.dart

@@ -10,7 +10,7 @@ void main() {
   testWidgets('CircleAvatar with background color', (WidgetTester tester) async {
     final Color backgroundColor = Colors.blue.shade400;
     await tester.pumpWidget(
-      new Center(
+      wrap(
         child: new CircleAvatar(
           backgroundColor: backgroundColor,
           radius: 50.0,
@@ -33,7 +33,7 @@ void main() {
   testWidgets('CircleAvatar with foreground color', (WidgetTester tester) async {
     final Color foregroundColor = Colors.red.shade100;
     await tester.pumpWidget(
-      new Center(
+      wrap(
         child: new CircleAvatar(
           foregroundColor: foregroundColor,
           child: const Text('Z'),
@@ -60,9 +60,9 @@ void main() {
       primaryColorBrightness: Brightness.light,
     );
     await tester.pumpWidget(
-      new Theme(
+      wrap(
+        child: new Theme(
           data: theme,
-        child: const Center(
           child: const CircleAvatar(
             child: const Text('Z'),
           ),
@@ -79,3 +79,10 @@ void main() {
     expect(paragraph.text.style.color, equals(theme.primaryTextTheme.title.color));
   });
 }
+
+Widget wrap({ Widget child }) {
+  return new Directionality(
+    textDirection: TextDirection.ltr,
+    child: new Center(child: child),
+  );
+}

packages/flutter/test/material/expand_icon_test.dart

@@ -10,15 +10,13 @@ void main() {
     bool expanded = false;
 
     await tester.pumpWidget(
-      new Material(
-        child: new Center(
+      wrap(
           child: new ExpandIcon(
             onPressed: (bool isExpanded) {
               expanded = !expanded;
             }
           )
       )
-      )
     );
 
     expect(expanded, isFalse);
@@ -31,13 +29,11 @@ void main() {
 
   testWidgets('ExpandIcon disabled', (WidgetTester tester) async {
     await tester.pumpWidget(
-      const Material(
-        child: const Center(
+      wrap(
           child: const ExpandIcon(
             onPressed: null
           )
       )
-      )
     );
 
     final IconTheme iconTheme = tester.firstWidget(find.byType(IconTheme));
@@ -48,8 +44,7 @@ void main() {
     bool expanded = false;
 
     await tester.pumpWidget(
-      new Material(
-        child: new Center(
+      wrap(
           child: new ExpandIcon(
             isExpanded: false,
             onPressed: (bool isExpanded) {
@@ -57,12 +52,10 @@ void main() {
             }
           )
       )
-      )
     );
 
     await tester.pumpWidget(
-      new Material(
-        child: new Center(
+      wrap(
           child: new ExpandIcon(
             isExpanded: true,
             onPressed: (bool isExpanded) {
@@ -70,9 +63,17 @@ void main() {
             }
         )
       )
-      )
     );
 
     expect(expanded, isFalse);
   });
 }
+
+Widget wrap({ Widget child }) {
+  return new Directionality(
+    textDirection: TextDirection.ltr,
+    child: new Center(
+      child: new Material(child: child),
+    ),
+  );
+}

packages/flutter/test/material/feedback_test.dart

@@ -154,7 +154,7 @@ class TestWidget extends StatelessWidget {
     return new GestureDetector(
         onTap: tapHandler(context),
         onLongPress: longPressHandler(context),
-        child: const Text('X'),
+        child: const Text('X', textDirection: TextDirection.ltr),
     );
   }
 }

packages/flutter/test/material/floating_action_button_test.dart

@@ -6,11 +6,12 @@ import 'package:flutter/material.dart';
 import 'package:flutter_test/flutter_test.dart';
 
 void main() {
-  testWidgets('Floating Action Button control test',
-      (WidgetTester tester) async {
+  testWidgets('Floating Action Button control test', (WidgetTester tester) async {
     bool didPressButton = false;
     await tester.pumpWidget(
-      new Center(
+      new Directionality(
+        textDirection: TextDirection.ltr,
+        child: new Center(
           child: new FloatingActionButton(
             onPressed: () {
               didPressButton = true;
@@ -18,6 +19,7 @@ void main() {
             child: const Icon(Icons.add),
           ),
         ),
+      ),
     );
 
     expect(didPressButton, isFalse);

packages/flutter/test/material/grid_title_test.dart

@@ -38,7 +38,12 @@ void main() {
     expect(tester.getBottomLeft(find.byKey(headerKey)).dy,
            lessThan(tester.getTopLeft(find.byKey(footerKey)).dy));
 
-    await tester.pumpWidget(const GridTile(child: const Text('Simple')));
+    await tester.pumpWidget(
+      const Directionality(
+        textDirection: TextDirection.ltr,
+        child: const GridTile(child: const Text('Simple')),
+      ),
+    );
 
     expect(find.text('Simple'), findsOneWidget);
   });

packages/flutter/test/material/icon_button_test.dart

@@ -24,14 +24,12 @@ void main() {
 
   testWidgets('test default icon buttons are sized up to 48', (WidgetTester tester) async {
     await tester.pumpWidget(
-      new Material(
-        child: new Center(
+      wrap(
           child: new IconButton(
             onPressed: mockOnPressedFunction,
             icon: const Icon(Icons.link),
           ),
       ),
-      ),
     );
 
     final RenderBox iconButton = tester.renderObject(find.byType(IconButton));
@@ -43,15 +41,13 @@ void main() {
 
   testWidgets('test small icons are sized up to 48dp', (WidgetTester tester) async {
     await tester.pumpWidget(
-      new Material(
-        child: new Center(
+      wrap(
           child: new IconButton(
             iconSize: 10.0,
             onPressed: mockOnPressedFunction,
             icon: const Icon(Icons.link),
           ),
       ),
-      ),
     );
 
     final RenderBox iconButton = tester.renderObject(find.byType(IconButton));
@@ -60,8 +56,7 @@ void main() {
 
   testWidgets('test icons can be small when total size is >48dp', (WidgetTester tester) async {
     await tester.pumpWidget(
-      new Material(
-        child: new Center(
+      wrap(
           child: new IconButton(
             iconSize: 10.0,
             padding: const EdgeInsets.all(30.0),
@@ -69,7 +64,6 @@ void main() {
             icon: const Icon(Icons.link),
           ),
       ),
-      ),
     );
 
     final RenderBox iconButton = tester.renderObject(find.byType(IconButton));
@@ -78,8 +72,7 @@ void main() {
 
   testWidgets('test default icon buttons are constrained', (WidgetTester tester) async {
     await tester.pumpWidget(
-      new Material(
-        child: new Center(
+      wrap(
           child: new IconButton(
             padding: EdgeInsets.zero,
             onPressed: mockOnPressedFunction,
@@ -87,7 +80,6 @@ void main() {
             iconSize: 80.0,
           ),
       ),
-      ),
     );
 
     final RenderBox box = tester.renderObject(find.byType(IconButton));
@@ -120,15 +112,13 @@ void main() {
 
   testWidgets('test default padding', (WidgetTester tester) async {
     await tester.pumpWidget(
-      new Material(
-        child: new Center(
+      wrap(
           child: new IconButton(
             onPressed: mockOnPressedFunction,
             icon: const Icon(Icons.ac_unit),
             iconSize: 80.0,
           ),
       ),
-      ),
     );
 
     final RenderBox box = tester.renderObject(find.byType(IconButton));
@@ -203,15 +193,13 @@ void main() {
     final Color directSplashColor = const Color(0xFF00000F);
     final Color directHighlightColor = const Color(0xFF0000F0);
 
-    Widget buttonWidget = new Material(
-      child: new Center(
+    Widget buttonWidget = wrap(
         child: new IconButton(
           icon: const Icon(Icons.android),
           splashColor: directSplashColor,
           highlightColor: directHighlightColor,
           onPressed: () { /* enable the button */ },
         ),
-      ),
     );
 
     await tester.pumpWidget(
@@ -236,13 +224,11 @@ void main() {
     final Color themeSplashColor1 = const Color(0xFF000F00);
     final Color themeHighlightColor1 = const Color(0xFF00FF00);
 
-    buttonWidget = new Material(
-      child: new Center(
+    buttonWidget = wrap(
         child: new IconButton(
           icon: const Icon(Icons.android),
           onPressed: () { /* enable the button */ },
         ),
-      ),
     );
 
     await tester.pumpWidget(
@@ -285,3 +271,12 @@ void main() {
     await gesture.up();
   });
 }
+
+Widget wrap({ Widget child }) {
+  return new Directionality(
+    textDirection: TextDirection.ltr,
+    child: new Material(
+      child: new Center(child: child),
+    ),
+  );
+}

packages/flutter/test/material/refresh_indicator_test.dart

@@ -23,9 +23,8 @@ void main() {
   testWidgets('RefreshIndicator', (WidgetTester tester) async {
     refreshCalled = false;
     await tester.pumpWidget(
-      new Directionality(
-        textDirection: TextDirection.ltr,
-        child: new RefreshIndicator(
+      new MaterialApp(
+        home: new RefreshIndicator(
           onRefresh: refresh,
           child: new ListView(
             physics: const AlwaysScrollableScrollPhysics(),
@@ -51,9 +50,8 @@ void main() {
   testWidgets('RefreshIndicator - bottom', (WidgetTester tester) async {
     refreshCalled = false;
     await tester.pumpWidget(
-      new Directionality(
-        textDirection: TextDirection.ltr,
-        child: new RefreshIndicator(
+      new MaterialApp(
+        home: new RefreshIndicator(
           onRefresh: refresh,
           child: new ListView(
             reverse: true,
@@ -80,9 +78,8 @@ void main() {
   testWidgets('RefreshIndicator - top - position', (WidgetTester tester) async {
     refreshCalled = false;
     await tester.pumpWidget(
-      new Directionality(
-        textDirection: TextDirection.ltr,
-        child: new RefreshIndicator(
+      new MaterialApp(
+        home: new RefreshIndicator(
           onRefresh: holdRefresh,
           child: new ListView(
             physics: const AlwaysScrollableScrollPhysics(),
@@ -107,9 +104,8 @@ void main() {
   testWidgets('RefreshIndicator - bottom - position', (WidgetTester tester) async {
     refreshCalled = false;
     await tester.pumpWidget(
-      new Directionality(
-        textDirection: TextDirection.ltr,
-        child: new RefreshIndicator(
+      new MaterialApp(
+        home: new RefreshIndicator(
           onRefresh: holdRefresh,
           child: new ListView(
             reverse: true,
@@ -135,9 +131,8 @@ void main() {
   testWidgets('RefreshIndicator - no movement', (WidgetTester tester) async {
     refreshCalled = false;
     await tester.pumpWidget(
-      new Directionality(
-        textDirection: TextDirection.ltr,
-        child: new RefreshIndicator(
+      new MaterialApp(
+        home: new RefreshIndicator(
           onRefresh: refresh,
           child: new ListView(
             physics: const AlwaysScrollableScrollPhysics(),
@@ -164,9 +159,8 @@ void main() {
   testWidgets('RefreshIndicator - not enough', (WidgetTester tester) async {
     refreshCalled = false;
     await tester.pumpWidget(
-      new Directionality(
-        textDirection: TextDirection.ltr,
-        child: new RefreshIndicator(
+      new MaterialApp(
+        home: new RefreshIndicator(
           onRefresh: refresh,
           child: new ListView(
             physics: const AlwaysScrollableScrollPhysics(),
@@ -192,9 +186,8 @@ void main() {
   testWidgets('RefreshIndicator - show - slow', (WidgetTester tester) async {
     refreshCalled = false;
     await tester.pumpWidget(
-      new Directionality(
-        textDirection: TextDirection.ltr,
-        child: new RefreshIndicator(
+      new MaterialApp(
+        home: new RefreshIndicator(
           onRefresh: holdRefresh, // this one never returns
           child: new ListView(
             physics: const AlwaysScrollableScrollPhysics(),
@@ -236,9 +229,8 @@ void main() {
   testWidgets('RefreshIndicator - show - fast', (WidgetTester tester) async {
     refreshCalled = false;
     await tester.pumpWidget(
-      new Directionality(
-        textDirection: TextDirection.ltr,
-        child: new RefreshIndicator(
+      new MaterialApp(
+        home: new RefreshIndicator(
           onRefresh: refresh,
           child: new ListView(
             physics: const AlwaysScrollableScrollPhysics(),
@@ -281,9 +273,8 @@ void main() {
   testWidgets('RefreshIndicator - show - fast - twice', (WidgetTester tester) async {
     refreshCalled = false;
     await tester.pumpWidget(
-      new Directionality(
-        textDirection: TextDirection.ltr,
-        child: new RefreshIndicator(
+      new MaterialApp(
+        home: new RefreshIndicator(
           onRefresh: refresh,
           child: new ListView(
             physics: const AlwaysScrollableScrollPhysics(),

packages/flutter/test/material/text_field_test.dart

@@ -1260,7 +1260,7 @@ void main() {
   testWidgets('Cannot enter new lines onto single line TextField', (WidgetTester tester) async {
     final TextEditingController textController = new TextEditingController();
 
-    await tester.pumpWidget(new Material(
+    await tester.pumpWidget(boilerplate(
       child: new TextField(controller: textController, decoration: null),
     ));
 
@@ -1272,7 +1272,7 @@ void main() {
   testWidgets('Injected formatters are chained', (WidgetTester tester) async {
     final TextEditingController textController = new TextEditingController();
 
-    await tester.pumpWidget(new Material(
+    await tester.pumpWidget(boilerplate(
       child: new TextField(
         controller: textController,
         decoration: null,
@@ -1293,7 +1293,7 @@ void main() {
   testWidgets('Chained formatters are in sequence', (WidgetTester tester) async {
     final TextEditingController textController = new TextEditingController();
 
-    await tester.pumpWidget(new Material(
+    await tester.pumpWidget(boilerplate(
       child: new TextField(
         controller: textController,
         decoration: null,

packages/flutter/test/material/tooltip_test.dart

@@ -32,7 +32,9 @@ void main() {
   testWidgets('Does tooltip end up in the right place - center', (WidgetTester tester) async {
     final GlobalKey key = new GlobalKey();
     await tester.pumpWidget(
-      new Overlay(
+      new Directionality(
+        textDirection: TextDirection.ltr,
+        child: new Overlay(
           initialEntries: <OverlayEntry>[
             new OverlayEntry(
               builder: (BuildContext context) {
@@ -50,16 +52,17 @@ void main() {
                         preferBelow: false,
                         child: new Container(
                           width: 0.0,
-                        height: 0.0
-                      )
-                    )
+                          height: 0.0,
                         ),
-                ]
+                      ),
+                    ),
+                  ],
                 );
-            }
+              },
+            ),
+          ],
+        ),
       ),
-        ]
-      )
     );
     (key.currentState as dynamic).ensureTooltipVisible(); // before using "as dynamic" in your code, see note top of file
     await tester.pump(const Duration(seconds: 2)); // faded in, show timer started (and at 0.0)
@@ -85,7 +88,9 @@ void main() {
   testWidgets('Does tooltip end up in the right place - top left', (WidgetTester tester) async {
     final GlobalKey key = new GlobalKey();
     await tester.pumpWidget(
-      new Overlay(
+      new Directionality(
+        textDirection: TextDirection.ltr,
+        child: new Overlay(
           initialEntries: <OverlayEntry>[
             new OverlayEntry(
               builder: (BuildContext context) {
@@ -103,16 +108,17 @@ void main() {
                         preferBelow: false,
                         child: new Container(
                           width: 0.0,
-                        height: 0.0
-                      )
-                    )
+                          height: 0.0,
                         ),
-                ]
+                      ),
+                    ),
+                  ],
                 );
-            }
+              },
+            ),
+          ],
+        ),
       ),
-        ]
-      )
     );
     (key.currentState as dynamic).ensureTooltipVisible(); // before using "as dynamic" in your code, see note top of file
     await tester.pump(const Duration(seconds: 2)); // faded in, show timer started (and at 0.0)
@@ -134,7 +140,9 @@ void main() {
   testWidgets('Does tooltip end up in the right place - center prefer above fits', (WidgetTester tester) async {
     final GlobalKey key = new GlobalKey();
     await tester.pumpWidget(
-      new Overlay(
+      new Directionality(
+        textDirection: TextDirection.ltr,
+        child: new Overlay(
           initialEntries: <OverlayEntry>[
             new OverlayEntry(
               builder: (BuildContext context) {
@@ -152,16 +160,17 @@ void main() {
                         preferBelow: false,
                         child: new Container(
                           width: 0.0,
-                        height: 0.0
-                      )
-                    )
+                          height: 0.0,
                         ),
-                ]
+                      ),
+                    ),
+                  ],
                 );
-            }
+              },
+            ),
+          ],
+        ),
       ),
-        ]
-      )
     );
     (key.currentState as dynamic).ensureTooltipVisible(); // before using "as dynamic" in your code, see note top of file
     await tester.pump(const Duration(seconds: 2)); // faded in, show timer started (and at 0.0)
@@ -185,7 +194,9 @@ void main() {
   testWidgets('Does tooltip end up in the right place - center prefer above does not fit', (WidgetTester tester) async {
     final GlobalKey key = new GlobalKey();
     await tester.pumpWidget(
-      new Overlay(
+      new Directionality(
+        textDirection: TextDirection.ltr,
+        child: new Overlay(
           initialEntries: <OverlayEntry>[
             new OverlayEntry(
               builder: (BuildContext context) {
@@ -203,16 +214,17 @@ void main() {
                         preferBelow: false,
                         child: new Container(
                           width: 0.0,
-                        height: 0.0
-                      )
-                    )
+                          height: 0.0,
                         ),
-                ]
+                      ),
+                    ),
+                  ],
                 );
-            }
+              },
+            ),
+          ],
+        ),
       ),
-        ]
-      )
     );
     (key.currentState as dynamic).ensureTooltipVisible(); // before using "as dynamic" in your code, see note top of file
     await tester.pump(const Duration(seconds: 2)); // faded in, show timer started (and at 0.0)
@@ -247,7 +259,9 @@ void main() {
   testWidgets('Does tooltip end up in the right place - center prefer below fits', (WidgetTester tester) async {
     final GlobalKey key = new GlobalKey();
     await tester.pumpWidget(
-      new Overlay(
+      new Directionality(
+        textDirection: TextDirection.ltr,
+        child: new Overlay(
           initialEntries: <OverlayEntry>[
             new OverlayEntry(
               builder: (BuildContext context) {
@@ -265,16 +279,17 @@ void main() {
                         preferBelow: true,
                         child: new Container(
                           width: 0.0,
-                        height: 0.0
-                      )
-                    )
+                          height: 0.0,
                         ),
-                ]
+                      ),
+                    ),
+                  ],
                 );
-            }
+              },
+            ),
+          ],
+        ),
       ),
-        ]
-      )
     );
     (key.currentState as dynamic).ensureTooltipVisible(); // before using "as dynamic" in your code, see note top of file
     await tester.pump(const Duration(seconds: 2)); // faded in, show timer started (and at 0.0)
@@ -297,7 +312,9 @@ void main() {
   testWidgets('Does tooltip end up in the right place - way off to the right', (WidgetTester tester) async {
     final GlobalKey key = new GlobalKey();
     await tester.pumpWidget(
-      new Overlay(
+      new Directionality(
+        textDirection: TextDirection.ltr,
+        child: new Overlay(
           initialEntries: <OverlayEntry>[
             new OverlayEntry(
               builder: (BuildContext context) {
@@ -315,16 +332,17 @@ void main() {
                         preferBelow: true,
                         child: new Container(
                           width: 0.0,
-                        height: 0.0
-                      )
-                    )
+                          height: 0.0,
                         ),
-                ]
+                      ),
+                    ),
+                  ],
                 );
-            }
+              },
+            ),
+          ],
+        ),
       ),
-        ]
-      )
     );
     (key.currentState as dynamic).ensureTooltipVisible(); // before using "as dynamic" in your code, see note top of file
     await tester.pump(const Duration(seconds: 2)); // faded in, show timer started (and at 0.0)
@@ -349,7 +367,9 @@ void main() {
   testWidgets('Does tooltip end up in the right place - near the edge', (WidgetTester tester) async {
     final GlobalKey key = new GlobalKey();
     await tester.pumpWidget(
-      new Overlay(
+      new Directionality(
+        textDirection: TextDirection.ltr,
+        child: new Overlay(
           initialEntries: <OverlayEntry>[
             new OverlayEntry(
               builder: (BuildContext context) {
@@ -367,16 +387,17 @@ void main() {
                         preferBelow: true,
                         child: new Container(
                           width: 0.0,
-                        height: 0.0
-                      )
-                    )
+                          height: 0.0,
                         ),
-                ]
+                      ),
+                    ),
+                  ],
                 );
-            }
+              },
+            ),
+          ],
+        ),
       ),
-        ]
-      )
     );
     (key.currentState as dynamic).ensureTooltipVisible(); // before using "as dynamic" in your code, see note top of file
     await tester.pump(const Duration(seconds: 2)); // faded in, show timer started (and at 0.0)
@@ -438,7 +459,9 @@ void main() {
 
     final GlobalKey key = new GlobalKey();
     await tester.pumpWidget(
-      new Overlay(
+      new Directionality(
+        textDirection: TextDirection.ltr,
+        child: new Overlay(
           initialEntries: <OverlayEntry>[
             new OverlayEntry(
               builder: (BuildContext context) {
@@ -450,15 +473,16 @@ void main() {
                       child: new Tooltip(
                         key: key,
                         message: tooltipText,
-                      child: new Container(width: 0.0, height: 0.0)
-                    )
+                        child: new Container(width: 0.0, height: 0.0),
                       ),
-                ]
+                    ),
+                  ],
                 );
-            }
+              },
+            ),
+          ],
+        ),
       ),
-        ]
-      )
     );
 
     expect(semantics, hasSemantics(new TestSemantics.root(label: tooltipText)));
@@ -504,7 +528,8 @@ void main() {
 
   testWidgets('Haptic feedback', (WidgetTester tester) async {
     final FeedbackTester feedback = new FeedbackTester();
-    await tester.pumpWidget(new MaterialApp(
+    await tester.pumpWidget(
+      new MaterialApp(
         home: new Center(
           child: new Tooltip(
             message: 'Foo',
@@ -512,10 +537,10 @@ void main() {
               width: 100.0,
               height: 100.0,
               color: Colors.green[500],
-                )
-            )
-        )
-      )
+            ),
+          ),
+        ),
+      ),
     );
 
     await tester.longPress(find.byType(Tooltip));

packages/flutter/test/painting/text_painter_test.dart

@@ -2,7 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-import 'dart:io' as io;
 import 'dart:ui' as ui;
 
 import 'package:flutter/painting.dart';
@@ -10,7 +9,8 @@ import 'package:flutter_test/flutter_test.dart';
 
 void main() {
   test('TextPainter caret test', () {
-    final TextPainter painter = new TextPainter();
+    final TextPainter painter = new TextPainter()
+      ..textDirection = TextDirection.ltr;
 
     String text = 'A';
     painter.text = new TextSpan(text: text);
@@ -27,13 +27,20 @@ void main() {
     painter.layout();
     caretOffset = painter.getOffsetForCaret(new ui.TextPosition(offset: text.length), ui.Rect.zero);
     expect(caretOffset.dx, painter.width);
-  }, skip: io.Platform.isMacOS); // TODO(goderbauer): Disabled because of https://github.com/flutter/flutter/issues/4273
+  });
 
   test('TextPainter error test', () {
-    final TextPainter painter = new TextPainter();
+    final TextPainter painter = new TextPainter(textDirection: TextDirection.ltr);
     expect(() { painter.paint(null, Offset.zero); }, throwsFlutterError);
   });
 
+  test('TextPainter requires textDirection', () {
+    final TextPainter painter1 = new TextPainter(text: const TextSpan(text: ''));
+    expect(() { painter1.layout(); }, throwsAssertionError);
+    final TextPainter painter2 = new TextPainter(text: const TextSpan(text: ''), textDirection: TextDirection.rtl);
+    expect(() { painter2.layout(); }, isNot(throwsException));
+  });
+
   test('TextPainter size test', () {
     final TextPainter painter = new TextPainter(
       text: const TextSpan(
@@ -44,20 +51,27 @@ void main() {
           fontSize: 123.0,
         ),
       ),
+      textDirection: TextDirection.ltr,
     );
     painter.layout();
     expect(painter.size, const Size(123.0, 123.0));
   });
 
   test('TextPainter default text height is 14 pixels', () {
-    final TextPainter painter = new TextPainter(text: const TextSpan(text: 'x'));
+    final TextPainter painter = new TextPainter(
+      text: const TextSpan(text: 'x'),
+      textDirection: TextDirection.ltr,
+    );
     painter.layout();
     expect(painter.preferredLineHeight, 14.0);
     expect(painter.size, const Size(14.0, 14.0));
   });
 
   test('TextPainter sets paragraph size from root', () {
-    final TextPainter painter = new TextPainter(text: const TextSpan(text: 'x', style: const TextStyle(fontSize: 100.0)));
+    final TextPainter painter = new TextPainter(
+      text: const TextSpan(text: 'x', style: const TextStyle(fontSize: 100.0)),
+      textDirection: TextDirection.ltr,
+    );
     painter.layout();
     expect(painter.preferredLineHeight, 100.0);
     expect(painter.size, const Size(100.0, 100.0));

packages/flutter/test/painting/text_style_test.dart

@@ -8,7 +8,7 @@ import 'package:flutter/painting.dart';
 import 'package:test/test.dart';
 
 void main() {
-  test("TextStyle control test", () {
+  test('TextStyle control test', () {
     expect(
       const TextStyle(inherit: false).toString(),
       equals('TextStyle(inherit: false, <no style specified>)'),
@@ -117,9 +117,17 @@ void main() {
 
     final ui.ParagraphStyle ps2 = s2.getParagraphStyle(textAlign: TextAlign.center);
     expect(ps2, equals(new ui.ParagraphStyle(textAlign: TextAlign.center, fontWeight: FontWeight.w800, fontSize: 10.0, lineHeight: 100.0)));
-    expect(ps2.toString(), 'ParagraphStyle(textAlign: TextAlign.center, fontWeight: FontWeight.w800, fontStyle: unspecified, maxLines: unspecified, fontFamily: unspecified, fontSize: 10.0, lineHeight: 100.0x, ellipsis: unspecified)');
+    expect(ps2.toString(), 'ParagraphStyle(textAlign: TextAlign.center, textDirection: unspecified, fontWeight: FontWeight.w800, fontStyle: unspecified, maxLines: unspecified, fontFamily: unspecified, fontSize: 10.0, lineHeight: 100.0x, ellipsis: unspecified)');
     final ui.ParagraphStyle ps5 = s5.getParagraphStyle();
     expect(ps5, equals(new ui.ParagraphStyle(fontWeight: FontWeight.w700, fontSize: 12.0, lineHeight: 123.0)));
-    expect(ps5.toString(), 'ParagraphStyle(textAlign: unspecified, fontWeight: FontWeight.w700, fontStyle: unspecified, maxLines: unspecified, fontFamily: unspecified, fontSize: 12.0, lineHeight: 123.0x, ellipsis: unspecified)');
+    expect(ps5.toString(), 'ParagraphStyle(textAlign: unspecified, textDirection: unspecified, fontWeight: FontWeight.w700, fontStyle: unspecified, maxLines: unspecified, fontFamily: unspecified, fontSize: 12.0, lineHeight: 123.0x, ellipsis: unspecified)');
+
+    final ui.ParagraphStyle ps6 = const TextStyle().getParagraphStyle(textDirection: TextDirection.ltr);
+    expect(ps6, equals(new ui.ParagraphStyle(textDirection: TextDirection.ltr)));
+    expect(ps6.toString(), 'ParagraphStyle(textAlign: unspecified, textDirection: TextDirection.ltr, fontWeight: unspecified, fontStyle: unspecified, maxLines: unspecified, fontFamily: unspecified, fontSize: unspecified, lineHeight: unspecified, ellipsis: unspecified)');
+
+    final ui.ParagraphStyle ps7 = const TextStyle().getParagraphStyle(textDirection: TextDirection.rtl);
+    expect(ps7, equals(new ui.ParagraphStyle(textDirection: TextDirection.rtl)));
+    expect(ps7.toString(), 'ParagraphStyle(textAlign: unspecified, textDirection: TextDirection.rtl, fontWeight: unspecified, fontStyle: unspecified, maxLines: unspecified, fontFamily: unspecified, fontSize: unspecified, lineHeight: unspecified, ellipsis: unspecified)');
   });
 }

packages/flutter/test/rendering/box_test.dart

@@ -73,8 +73,8 @@ void main() {
     expect(coloredBox, hasAGoodToStringDeep);
     expect(coloredBox.toStringDeep(), equalsIgnoringHashCodes(
         'RenderDecoratedBox#00000 NEEDS-LAYOUT NEEDS-PAINT DETACHED\n'
-        '   parentData: null\n'
-        '   constraints: null\n'
+        '   parentData: MISSING\n'
+        '   constraints: MISSING\n'
         '   size: MISSING\n'
         '   decoration: BoxDecoration:\n'
         '     <no decorations specified>\n'

packages/flutter/test/rendering/editable_test.dart

@@ -12,6 +12,8 @@ void main() {
         style: const TextStyle(height: 1.0, fontSize: 10.0, fontFamily: 'Ahem'),
         text: '12345',
       ),
+      textAlign: TextAlign.start,
+      textDirection: TextDirection.ltr,
       offset: new ViewportOffset.zero(),
     );
     expect(editable.getMinIntrinsicWidth(double.INFINITY), 50.0);
@@ -23,8 +25,8 @@ void main() {
       editable.toStringDeep(),
       equalsIgnoringHashCodes(
         'RenderEditable#00000 NEEDS-LAYOUT NEEDS-PAINT DETACHED\n'
-        ' │ parentData: null\n'
-        ' │ constraints: null\n'
+        ' │ parentData: MISSING\n'
+        ' │ constraints: MISSING\n'
         ' │ size: MISSING\n'
         ' │ cursorColor: null\n'
         ' │ showCursor: ValueNotifier<bool>#00000(false)\n'

packages/flutter/test/rendering/flex_test.dart

@@ -91,8 +91,8 @@ void main() {
       flex.toStringDeep(),
       equalsIgnoringHashCodes(
         'RenderFlex#00000 NEEDS-LAYOUT NEEDS-PAINT DETACHED\n'
-        '   parentData: null\n'
-        '   constraints: null\n'
+        '   parentData: MISSING\n'
+        '   constraints: MISSING\n'
         '   size: MISSING\n'
         '   direction: horizontal\n'
         '   mainAxisAlignment: start\n'

packages/flutter/test/rendering/overflow_test.dart

@@ -9,13 +9,16 @@ import 'package:test/test.dart';
 import 'rendering_tester.dart';
 
 void main() {
-  test("overflow should not affect baseline", () {
+  test('overflow should not affect baseline', () {
     RenderBox root, child, text;
     double baseline1, baseline2, height1, height2;
 
     root = new RenderPositionedBox(
       child: new RenderCustomPaint(
-        child: child = text = new RenderParagraph(const TextSpan(text: 'Hello World')),
+        child: child = text = new RenderParagraph(
+          const TextSpan(text: 'Hello World'),
+          textDirection: TextDirection.ltr,
+        ),
         painter: new TestCallbackPainter(
           onPaint: () {
             baseline1 = child.getDistanceToBaseline(TextBaseline.alphabetic);
@@ -29,7 +32,10 @@ void main() {
     root = new RenderPositionedBox(
       child: new RenderCustomPaint(
         child: child = new RenderConstrainedOverflowBox(
-          child: text = new RenderParagraph(const TextSpan(text: 'Hello World')),
+          child: text = new RenderParagraph(
+            const TextSpan(text: 'Hello World'),
+            textDirection: TextDirection.ltr,
+          ),
           maxHeight: height1 / 2.0,
           alignment: const FractionalOffset(0.0, 0.0)
         ),

packages/flutter/test/rendering/paragraph_intrinsics_test.dart

@@ -10,8 +10,9 @@ void main() {
     final RenderParagraph paragraph = new RenderParagraph(
       const TextSpan(
         style: const TextStyle(height: 1.0),
-        text: 'Hello World'
-      )
+        text: 'Hello World',
+      ),
+      textDirection: TextDirection.ltr,
     );
     final RenderListBody testBlock = new RenderListBody(
       children: <RenderBox>[

packages/flutter/test/rendering/paragraph_test.dart

@@ -14,7 +14,10 @@ const String _kText = 'I polished up that handle so carefullee\nThat now I am th
 
 void main() {
   test('getOffsetForCaret control test', () {
-    final RenderParagraph paragraph = new RenderParagraph(const TextSpan(text: _kText));
+    final RenderParagraph paragraph = new RenderParagraph(
+      const TextSpan(text: _kText),
+      textDirection: TextDirection.ltr,
+    );
     layout(paragraph);
 
     final Rect caret = new Rect.fromLTWH(0.0, 0.0, 2.0, 20.0);
@@ -30,7 +33,10 @@ void main() {
   });
 
   test('getPositionForOffset control test', () {
-    final RenderParagraph paragraph = new RenderParagraph(const TextSpan(text: _kText));
+    final RenderParagraph paragraph = new RenderParagraph(
+      const TextSpan(text: _kText),
+      textDirection: TextDirection.ltr,
+    );
     layout(paragraph);
 
     final TextPosition position20 = paragraph.getPositionForOffset(const Offset(20.0, 5.0));
@@ -44,7 +50,10 @@ void main() {
   });
 
   test('getBoxesForSelection control test', () {
-    final RenderParagraph paragraph = new RenderParagraph(const TextSpan(text: _kText));
+    final RenderParagraph paragraph = new RenderParagraph(
+      const TextSpan(text: _kText),
+      textDirection: TextDirection.ltr,
+    );
     layout(paragraph);
 
     List<ui.TextBox> boxes = paragraph.getBoxesForSelection(
@@ -61,7 +70,10 @@ void main() {
   });
 
   test('getWordBoundary control test', () {
-    final RenderParagraph paragraph = new RenderParagraph(const TextSpan(text: _kText));
+    final RenderParagraph paragraph = new RenderParagraph(
+      const TextSpan(text: _kText),
+      textDirection: TextDirection.ltr,
+    );
     layout(paragraph);
 
     final TextRange range5 = paragraph.getWordBoundary(const TextPosition(offset: 5));
@@ -81,6 +93,7 @@ void main() {
               'is a wrapping test. It should wrap at manual newlines, and if softWrap is true, also at spaces.',
         style: const TextStyle(fontFamily: 'Ahem', fontSize: 10.0),
       ),
+      textDirection: TextDirection.ltr,
       maxLines: 1,
       softWrap: true,
     );
@@ -157,6 +170,7 @@ void main() {
             // 0          1          2       3       4      5     6         7         8    9       10      11     12
         style: const TextStyle(fontFamily: 'Ahem', fontSize: 10.0),
       ),
+      textDirection: TextDirection.ltr,
     );
     layout(paragraph, constraints: const BoxConstraints(maxWidth: 100.0));
     void layoutAt(int maxLines) {
@@ -183,6 +197,7 @@ void main() {
         text: 'Hello',
         style: const TextStyle(color: const Color(0xFF000000)),
       ),
+      textDirection: TextDirection.ltr,
     );
     layout(paragraph, constraints: const BoxConstraints(maxWidth: 100.0), phase: EnginePhase.paint);
     expect(paragraph.debugNeedsLayout, isFalse);
@@ -210,15 +225,21 @@ void main() {
   test('toStringDeep', () {
     final RenderParagraph paragraph = new RenderParagraph(
       const TextSpan(text: _kText),
+      textDirection: TextDirection.ltr,
     );
     expect(paragraph, hasAGoodToStringDeep);
     expect(
       paragraph.toStringDeep(),
       equalsIgnoringHashCodes(
         'RenderParagraph#00000 NEEDS-LAYOUT NEEDS-PAINT DETACHED\n'
-        ' │ parentData: null\n'
-        ' │ constraints: null\n'
+        ' │ parentData: MISSING\n'
+        ' │ constraints: MISSING\n'
         ' │ size: MISSING\n'
+        ' │ textAlign: start\n'
+        ' │ textDirection: ltr\n'
+        ' │ softWrap: wrapping at box width\n'
+        ' │ overflow: clip\n'
+        ' │ maxLines: unlimited\n'
         ' ╘═╦══ text ═══\n'
         '   ║ TextSpan:\n'
         '   ║   "I polished up that handle so carefullee\n'

packages/flutter/test/rendering/semantics_and_children_test.dart

@@ -16,7 +16,12 @@ int countSemanticsChildren(RenderObject object) {
     
 void main() {
   test('RenderOpacity and children and semantics', () {
-    final RenderOpacity box = new RenderOpacity(child: new RenderParagraph(const TextSpan()));
+    final RenderOpacity box = new RenderOpacity(
+      child: new RenderParagraph(
+        const TextSpan(),
+        textDirection: TextDirection.ltr,
+      ),
+    );
     expect(countSemanticsChildren(box), 1);
     box.opacity = 0.5;
     expect(countSemanticsChildren(box), 1);

packages/flutter/test/rendering/slivers_test.dart

@@ -19,8 +19,8 @@ void main() {
       root.toStringDeep(),
       equalsIgnoringHashCodes(
         'RenderViewport#00000 NEEDS-LAYOUT NEEDS-PAINT DETACHED\n'
-        '   parentData: null\n'
-        '   constraints: null\n'
+        '   parentData: MISSING\n'
+        '   constraints: MISSING\n'
         '   size: MISSING\n'
         '   axisDirection: down\n'
         '   crossAxisDirection: right\n'

packages/flutter/test/rendering/wrap_test.dart

@@ -13,8 +13,8 @@ void main() {
       renderWrap.toStringDeep(),
       equalsIgnoringHashCodes(
         'RenderWrap#00000 NEEDS-LAYOUT NEEDS-PAINT DETACHED\n'
-        '   parentData: null\n'
-        '   constraints: null\n'
+        '   parentData: MISSING\n'
+        '   constraints: MISSING\n'
         '   size: MISSING\n'
         '   direction: horizontal\n'
         '   alignment: start\n'

packages/flutter/test/widgets/animated_container_test.dart

@@ -230,7 +230,7 @@ void main() {
           duration: const Duration(milliseconds: 200),
           width: 100.0,
           height: 100.0,
-          child: const Text('X')
+          child: const Text('X', textDirection: TextDirection.ltr)
         )
       )
     );
@@ -250,7 +250,7 @@ void main() {
           duration: const Duration(milliseconds: 200),
           width: 200.0,
           height: 200.0,
-          child: const Text('X')
+          child: const Text('X', textDirection: TextDirection.ltr)
         )
       )
     );
@@ -274,7 +274,7 @@ void main() {
           duration: const Duration(milliseconds: 200),
           width: 200.0,
           height: 100.0,
-          child: const Text('X')
+          child: const Text('X', textDirection: TextDirection.ltr)
         )
       )
     );

packages/flutter/test/widgets/animated_cross_fade_test.dart

@@ -302,16 +302,16 @@ void main() {
 
   testWidgets('AnimatedCrossFade.layoutBuilder', (WidgetTester tester) async {
     await tester.pumpWidget(const AnimatedCrossFade(
-      firstChild: const Text('AAA'),
-      secondChild: const Text('BBB'),
+      firstChild: const Text('AAA', textDirection: TextDirection.ltr),
+      secondChild: const Text('BBB', textDirection: TextDirection.ltr),
       crossFadeState: CrossFadeState.showFirst,
       duration: const Duration(milliseconds: 50),
     ));
     expect(find.text('AAA'), findsOneWidget);
     expect(find.text('BBB'), findsOneWidget);
     await tester.pumpWidget(new AnimatedCrossFade(
-      firstChild: const Text('AAA'),
-      secondChild: const Text('BBB'),
+      firstChild: const Text('AAA', textDirection: TextDirection.ltr),
+      secondChild: const Text('BBB', textDirection: TextDirection.ltr),
       crossFadeState: CrossFadeState.showFirst,
       duration: const Duration(milliseconds: 50),
       layoutBuilder: (Widget a, Key aKey, Widget b, Key bKey) => a,
@@ -319,8 +319,8 @@ void main() {
     expect(find.text('AAA'), findsOneWidget);
     expect(find.text('BBB'), findsNothing);
     await tester.pumpWidget(new AnimatedCrossFade(
-      firstChild: const Text('AAA'),
-      secondChild: const Text('BBB'),
+      firstChild: const Text('AAA', textDirection: TextDirection.ltr),
+      secondChild: const Text('BBB', textDirection: TextDirection.ltr),
       crossFadeState: CrossFadeState.showSecond,
       duration: const Duration(milliseconds: 50),
       layoutBuilder: (Widget a, Key aKey, Widget b, Key bKey) => a,

packages/flutter/test/widgets/animated_list_test.dart

@@ -121,7 +121,7 @@ void main() {
         child: new SizedBox(
           height: 100.0,
           child: new Center(
-            child: new Text('item $item'),
+            child: new Text('item $item', textDirection: TextDirection.ltr),
           ),
         ),
       );

packages/flutter/test/widgets/async_test.dart

@@ -9,7 +9,7 @@ import 'package:flutter_test/flutter_test.dart';
 
 void main() {
   Widget snapshotText(BuildContext context, AsyncSnapshot<String> snapshot) {
-    return new Text(snapshot.toString());
+    return new Text(snapshot.toString(), textDirection: TextDirection.ltr);
   }
   group('AsyncSnapshot', () {
     test('requiring data succeeds if data is present', () {
@@ -280,5 +280,5 @@ class StringCollector extends StreamBuilderBase<String, List<String>> {
   List<String> afterDisconnected(List<String> current) => current..add('disc');
 
   @override
-  Widget build(BuildContext context, List<String> currentSummary) => new Text(currentSummary.join(', '));
+  Widget build(BuildContext context, List<String> currentSummary) => new Text(currentSummary.join(', '), textDirection: TextDirection.ltr);
 }

packages/flutter/test/widgets/banner_test.dart

@@ -19,7 +19,8 @@ class TestCanvas implements Canvas {
 void main() {
   test('A Banner with a location of topLeft paints in the top left', () {
     final BannerPainter bannerPainter = new BannerPainter(
-      message:"foo",
+      message: 'foo',
+      textDirection: TextDirection.ltr,
       location: BannerLocation.topLeft
     );
 
@@ -45,7 +46,8 @@ void main() {
 
   test('A Banner with a location of topRight paints in the top right', () {
     final BannerPainter bannerPainter = new BannerPainter(
-      message:"foo",
+      message: 'foo',
+      textDirection: TextDirection.ltr,
       location: BannerLocation.topRight
     );
 
@@ -71,7 +73,8 @@ void main() {
 
   test('A Banner with a location of bottomLeft paints in the bottom left', () {
     final BannerPainter bannerPainter = new BannerPainter(
-      message:"foo",
+      message: 'foo',
+      textDirection: TextDirection.ltr,
       location: BannerLocation.bottomLeft
     );
 
@@ -97,7 +100,8 @@ void main() {
 
   test('A Banner with a location of bottomRight paints in the bottom right', () {
     final BannerPainter bannerPainter = new BannerPainter(
-      message:"foo",
+      message: 'foo',
+      textDirection: TextDirection.ltr,
       location: BannerLocation.bottomRight
     );
 

packages/flutter/test/widgets/baseline_test.dart

@@ -14,7 +14,7 @@ void main() {
             fontFamily: 'Ahem',
             fontSize: 100.0,
           ),
-          child: const Text('X'),
+          child: const Text('X', textDirection: TextDirection.ltr),
         ),
       ),
     );
@@ -32,7 +32,7 @@ void main() {
               fontFamily: 'Ahem',
               fontSize: 100.0,
             ),
-            child: const Text('X'),
+            child: const Text('X', textDirection: TextDirection.ltr),
           ),
         ),
       ),

packages/flutter/test/widgets/clamp_overscrolls_test.dart

@@ -21,9 +21,9 @@ Widget buildFrame(ScrollPhysics physics) {
         crossAxisAlignment: CrossAxisAlignment.start,
         textDirection: TextDirection.ltr,
         children: <Widget>[
-          const SizedBox(height: 100.0, child: const Text('top')),
+          const SizedBox(height: 100.0, child: const Text('top', textDirection: TextDirection.ltr)),
           new Expanded(child: new Container()),
-          const SizedBox(height: 100.0, child: const Text('bottom')),
+          const SizedBox(height: 100.0, child: const Text('bottom', textDirection: TextDirection.ltr)),
         ],
       ),
     ),

packages/flutter/test/widgets/default_text_style_test.dart

@@ -7,7 +7,7 @@ import 'package:flutter/widgets.dart';
 
 void main() {
   testWidgets('DefaultTextStyle changes propagate to Text', (WidgetTester tester) async {
-    const Text textWidget = const Text('Hello');
+    const Text textWidget = const Text('Hello', textDirection: TextDirection.ltr);
     const TextStyle s1 = const TextStyle(
       fontSize: 10.0,
       fontWeight: FontWeight.w800,
@@ -16,7 +16,7 @@ void main() {
 
     await tester.pumpWidget(const DefaultTextStyle(
       style: s1,
-      child: textWidget
+      child: textWidget,
     ));
 
     RichText text = tester.firstWidget(find.byType(RichText));

packages/flutter/test/widgets/dismissible_test.dart

@@ -14,7 +14,9 @@ List<int> dismissedItems = <int>[];
 Widget background;
 
 Widget buildTest({ double startToEndThreshold }) {
-  return new StatefulBuilder(
+  return new Directionality(
+    textDirection: TextDirection.ltr,
+    child: new StatefulBuilder(
       builder: (BuildContext context, StateSetter setState) {
         Widget buildDismissibleItem(int item) {
           return new Dismissible(
@@ -56,6 +58,7 @@ Widget buildTest({ double startToEndThreshold }) {
           ),
         );
       },
+    ),
   );
 }
 
@@ -287,7 +290,10 @@ void main() {
   // actually remove the dismissed widget, which is a violation of the
   // Dismissible contract. This is not an example of good practice.
   testWidgets('dismissing bottom then top (smoketest)', (WidgetTester tester) async {
-    await tester.pumpWidget(new Center(
+    await tester.pumpWidget(
+      new Directionality(
+        textDirection: TextDirection.ltr,
+        child: new Center(
           child: new Container(
             width: 100.0,
             height: 1000.0,
@@ -298,7 +304,9 @@ void main() {
               ],
             ),
           ),
-    ));
+        ),
+      ),
+    );
     expect(find.text('1'), findsOneWidget);
     expect(find.text('2'), findsOneWidget);
     await dismissElement(tester, find.text('2'), gestureDirection: DismissDirection.startToEnd);

packages/flutter/test/widgets/dispose_ancestor_lookup_test.dart

@@ -24,7 +24,7 @@ class TestWidgetState extends State<TestWidget> {
   }
 
   @override
-  Widget build(BuildContext context) => const Text('test');
+  Widget build(BuildContext context) => const Text('test', textDirection: TextDirection.ltr);
 }
 
 void main() {

packages/flutter/test/widgets/flex_test.dart

@@ -28,7 +28,7 @@ void main() {
                       width: 100.0,
                       height: 100.0,
                       child: const Center(
-                        child: const Text('X'),
+                        child: const Text('X', textDirection: TextDirection.ltr),
                       ),
                     ),
                   ),
@@ -63,8 +63,8 @@ void main() {
       new Row(
         textDirection: TextDirection.ltr,
         children: <Widget>[
-          const Expanded(flex: null, child: const Text('one')),
-          const Flexible(flex: null, child: const Text('two')),
+          const Expanded(flex: null, child: const Text('one', textDirection: TextDirection.ltr)),
+          const Flexible(flex: null, child: const Text('two', textDirection: TextDirection.ltr)),
         ],
       ),
     );

packages/flutter/test/widgets/flow_test.dart

@@ -44,7 +44,7 @@ void main() {
           width: 100.0,
           height: 100.0,
           color: const Color(0xFF0000FF),
-          child: new Text('$i')
+          child: new Text('$i', textDirection: TextDirection.ltr)
         )
       );
     }

packages/flutter/test/widgets/focus_test.dart

@@ -47,7 +47,7 @@ class TestFocusableState extends State<TestFocusable> {
       child: new AnimatedBuilder(
         animation: focusNode,
         builder: (BuildContext context, Widget child) {
-          return new Text(focusNode.hasFocus ? widget.yes : widget.no);
+          return new Text(focusNode.hasFocus ? widget.yes : widget.no, textDirection: TextDirection.ltr);
         },
       ),
     );

packages/flutter/test/widgets/form_test.dart

@@ -11,7 +11,9 @@ void main() {
     String fieldValue;
 
     Widget builder() {
-      return new Center(
+      return new Directionality(
+        textDirection: TextDirection.ltr,
+        child: new Center(
           child: new Material(
             child: new Form(
               key: formKey,
@@ -20,6 +22,7 @@ void main() {
               ),
             ),
           ),
+        ),
       );
     }
 
@@ -42,7 +45,9 @@ void main() {
     String fieldValue;
 
     Widget builder() {
-      return new Center(
+      return new Directionality(
+        textDirection: TextDirection.ltr,
+        child: new Center(
           child: new Material(
             child: new Form(
               child: new TextField(
@@ -50,6 +55,7 @@ void main() {
               ),
             ),
           ),
+        ),
       );
     }
 
@@ -72,7 +78,9 @@ void main() {
     String errorText(String value) => value + '/error';
 
     Widget builder(bool autovalidate) {
-      return new Center(
+      return new Directionality(
+        textDirection: TextDirection.ltr,
+        child: new Center(
           child: new Material(
             child: new Form(
               key: formKey,
@@ -82,6 +90,7 @@ void main() {
               ),
             ),
           ),
+        ),
       );
     }
 
@@ -162,7 +171,9 @@ void main() {
     final GlobalKey<FormFieldState<String>> inputKey = new GlobalKey<FormFieldState<String>>();
 
     Widget builder() {
-      return new Center(
+      return new Directionality(
+        textDirection: TextDirection.ltr,
+        child: new Center(
           child: new Material(
             child: new Form(
               child: new TextFormField(
@@ -171,6 +182,7 @@ void main() {
               ),
             ),
           ),
+        ),
       );
     }
 
@@ -198,7 +210,9 @@ void main() {
     String fieldValue;
 
     Widget builder(bool remove) {
-      return new Center(
+      return new Directionality(
+        textDirection: TextDirection.ltr,
+        child: new Center(
           child: new Material(
             child: new Form(
               key: formKey,
@@ -209,6 +223,7 @@ void main() {
               ),
             ),
           ),
+        ),
       );
     }
 

packages/flutter/test/widgets/global_keys_moving_test.dart

@@ -25,7 +25,7 @@ class StatefulLeafState extends State<StatefulLeaf> {
   void markNeedsBuild() { setState(() { }); }
 
   @override
-  Widget build(BuildContext context) => const Text('leaf');
+  Widget build(BuildContext context) => const Text('leaf', textDirection: TextDirection.ltr);
 }
 
 class KeyedWrapper extends StatelessWidget {

packages/flutter/test/widgets/hit_testing_test.dart

@@ -8,7 +8,7 @@ import 'package:flutter/widgets.dart';
 
 void main() {
   testWidgets('toString control test', (WidgetTester tester) async {
-    await tester.pumpWidget(const Center(child: const Text('Hello')));
+    await tester.pumpWidget(const Center(child: const Text('Hello', textDirection: TextDirection.ltr)));
     final HitTestResult result = tester.hitTestOnBinding(Offset.zero);
     expect(result, hasOneLineDescription);
     expect(result.path.first, hasOneLineDescription);

packages/flutter/test/widgets/hyperlink_test.dart

@@ -26,6 +26,7 @@ void main() {
       new Center(
         child: new RichText(
           key: textKey,
+          textDirection: TextDirection.ltr,
           text: new TextSpan(
             children: <TextSpan>[
               new TextSpan(

packages/flutter/test/widgets/icon_test.dart

@@ -8,13 +8,16 @@ import 'package:flutter/widgets.dart';
 void main() {
   testWidgets('Can set opacity for an Icon', (WidgetTester tester) async {
     await tester.pumpWidget(
-      const IconTheme(
+      const Directionality(
+        textDirection: TextDirection.ltr,
+        child: const IconTheme(
           data: const IconThemeData(
             color: const Color(0xFF666666),
             opacity: 0.5
           ),
           child: const Icon(const IconData(0xd0a0, fontFamily: 'Arial'))
-      )
+        ),
+      ),
     );
     final RichText text = tester.widget(find.byType(RichText));
     expect(text.text.style.color, const Color(0xFF666666).withOpacity(0.5));
@@ -22,9 +25,12 @@ void main() {
 
   testWidgets('Icon sizing - no theme, default size', (WidgetTester tester) async {
     await tester.pumpWidget(
-      const Center(
+      const Directionality(
+        textDirection: TextDirection.ltr,
+        child: const Center(
           child: const Icon(null),
         ),
+      ),
     );
 
     final RenderBox renderObject = tester.renderObject(find.byType(Icon));
@@ -33,12 +39,15 @@ void main() {
 
   testWidgets('Icon sizing - no theme, explicit size', (WidgetTester tester) async {
     await tester.pumpWidget(
-      const Center(
+      const Directionality(
+        textDirection: TextDirection.ltr,
+        child: const Center(
           child: const Icon(
             null,
             size: 96.0,
           ),
         ),
+      ),
     );
 
     final RenderBox renderObject = tester.renderObject(find.byType(Icon));
@@ -47,12 +56,15 @@ void main() {
 
   testWidgets('Icon sizing - sized theme', (WidgetTester tester) async {
     await tester.pumpWidget(
-      const Center(
+      const Directionality(
+        textDirection: TextDirection.ltr,
+        child: const Center(
           child: const IconTheme(
             data: const IconThemeData(size: 36.0),
             child: const Icon(null),
           ),
         ),
+      ),
     );
 
     final RenderBox renderObject = tester.renderObject(find.byType(Icon));
@@ -61,7 +73,9 @@ void main() {
 
   testWidgets('Icon sizing - sized theme, explicit size', (WidgetTester tester) async {
     await tester.pumpWidget(
-      const Center(
+      const Directionality(
+        textDirection: TextDirection.ltr,
+        child: const Center(
           child: const IconTheme(
             data: const IconThemeData(size: 36.0),
             child: const Icon(
@@ -69,6 +83,7 @@ void main() {
               size: 48.0,
             ),
           ),
+        ),
       )
     );
 
@@ -78,12 +93,15 @@ void main() {
 
   testWidgets('Icon sizing - sizeless theme, default size', (WidgetTester tester) async {
     await tester.pumpWidget(
-      const Center(
+      const Directionality(
+        textDirection: TextDirection.ltr,
+        child: const Center(
           child: const IconTheme(
             data: const IconThemeData(),
             child: const Icon(null),
           ),
         ),
+      ),
     );
 
     final RenderBox renderObject = tester.renderObject(find.byType(Icon));
@@ -93,9 +111,12 @@ void main() {
 
   testWidgets('Icon with custom font', (WidgetTester tester) async {
     await tester.pumpWidget(
-      const Center(
+      const Directionality(
+        textDirection: TextDirection.ltr,
+        child: const Center(
           child: const Icon(const IconData(0x41, fontFamily: 'Roboto')),
         ),
+      ),
     );
 
     final RichText richText = tester.firstWidget(find.byType(RichText));

packages/flutter/test/widgets/independent_widget_layout_test.dart

@@ -92,7 +92,7 @@ class TriggerableState extends State<TriggerableWidget> {
   @override
   Widget build(BuildContext context) {
     widget.counter.count++;
-    return new Text("Bang $_count!");
+    return new Text("Bang $_count!", textDirection: TextDirection.ltr);
   }
 }
 

packages/flutter/test/widgets/inherited_test.dart

@@ -129,7 +129,7 @@ void main() {
                           builder: (BuildContext context) {
                             final ValueInherited v = context.inheritFromWidgetOfExactType(ValueInherited);
                             log.add('a: ${v.value}');
-                            return const Text('');
+                            return const Text('', textDirection: TextDirection.ltr);
                           }
                         )
                       )
@@ -146,7 +146,7 @@ void main() {
                         builder: (BuildContext context) {
                           final ValueInherited v = context.inheritFromWidgetOfExactType(ValueInherited);
                           log.add('b: ${v.value}');
-                          return const Text('');
+                          return const Text('', textDirection: TextDirection.ltr);
                         }
                       )
                     )
@@ -204,7 +204,7 @@ void main() {
                           builder: (BuildContext context) {
                             final ValueInherited v = context.inheritFromWidgetOfExactType(ValueInherited);
                             log.add('a: ${v.value}');
-                            return const Text('');
+                            return const Text('', textDirection: TextDirection.ltr);
                           }
                         )
                       )
@@ -222,7 +222,7 @@ void main() {
                         builder: (BuildContext context) {
                           final ValueInherited v = context.inheritFromWidgetOfExactType(ValueInherited);
                           log.add('b: ${v.value}');
-                          return const Text('');
+                          return const Text('', textDirection: TextDirection.ltr);
                         }
                       )
                     )
@@ -265,7 +265,7 @@ void main() {
       builder: (BuildContext context) {
         final ValueInherited v = context.inheritFromWidgetOfExactType(ValueInherited);
         log.add(v.value);
-        return const Text('');
+        return const Text('', textDirection: TextDirection.ltr);
       }
     );
 
@@ -336,7 +336,7 @@ void main() {
       builder: (BuildContext context) {
         final ValueInherited v = context.inheritFromWidgetOfExactType(ValueInherited);
         log.add(v.value);
-        return const Text('');
+        return const Text('', textDirection: TextDirection.ltr);
       }
     );
 

packages/flutter/test/widgets/list_view_builder_test.dart

@@ -66,7 +66,7 @@ void main() {
         key: new ValueKey<int>(index),
         width: 500.0, // this should be ignored
         height: 400.0, // should be overridden by itemExtent
-        child: new Text('$index')
+        child: new Text('$index', textDirection: TextDirection.ltr)
       );
     };
 
@@ -79,7 +79,7 @@ void main() {
             itemExtent: 200.0,
             itemBuilder: itemBuilder,
           ),
-          right: const Text('Not Today')
+          right: const Text('Not Today'),
         ),
       );
     }
@@ -190,7 +190,7 @@ void main() {
 
     final IndexedWidgetBuilder itemBuilder = (BuildContext context, int index) {
       callbackTracker.add(index);
-      return new Text('$index', key: new ValueKey<int>(index));
+      return new Text('$index', key: new ValueKey<int>(index), textDirection: TextDirection.ltr);
     };
 
     final Widget testWidget = new Directionality(

packages/flutter/test/widgets/list_view_horizontal_test.dart

@@ -2,10 +2,10 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-import 'package:flutter_test/flutter_test.dart';
 import 'package:flutter/foundation.dart';
 import 'package:flutter/rendering.dart';
 import 'package:flutter/widgets.dart';
+import 'package:flutter_test/flutter_test.dart';
 
 const List<int> items = const <int>[0, 1, 2, 3, 4, 5];