Add geometry getters to Flutter Driver (#32302)

packages/flutter_driver/lib/src/common/geometry.dart

+// Copyright 2019 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_driver/src/common/enum_util.dart';
+
+import 'find.dart';
+import 'message.dart';
+
+/// Offset types that can be requested by [GetOffset].
+enum OffsetType {
+  /// The top left point.
+  topLeft,
+
+  /// The top right point.
+  topRight,
+
+  /// The bottom left point.
+  bottomLeft,
+
+  /// The bottom right point.
+  bottomRight,
+
+  /// The center point.
+  center,
+}
+
+EnumIndex<OffsetType> _offsetTypeIndex = EnumIndex<OffsetType>(OffsetType.values);
+
+/// A Flutter Driver command that return the [offsetType] from the RenderObject
+/// identified by [finder].
+class GetOffset extends CommandWithTarget {
+  /// The `finder` looks for an element to get its rect.
+  GetOffset(SerializableFinder finder,  this.offsetType, { Duration timeout }) : super(finder, timeout: timeout);
+
+  /// Deserializes this command from the value generated by [serialize].
+  GetOffset.deserialize(Map<String, dynamic> json)
+      : offsetType = _offsetTypeIndex.lookupBySimpleName(json['offsetType']),
+        super.deserialize(json);
+
+  @override
+  Map<String, String> serialize() => super.serialize()..addAll(<String, String>{
+    'offsetType': _offsetTypeIndex.toSimpleName(offsetType),
+  });
+
+  /// The type of the requested offset.
+  final OffsetType offsetType;
+
+  @override
+  final String kind = 'get_offset';
+}
+
+/// The result of the [GetRect] command.
+class GetOffsetResult extends Result {
+  /// Creates a result with the offset defined by [dx] and [dy].
+  GetOffsetResult({ this.dx = 0.0, this.dy = 0.0});
+
+  /// The x component of the offset.
+  final double dx;
+
+  /// The y component of the offset.
+  final double dy;
+
+  /// Deserializes the result from JSON.
+  static GetOffsetResult fromJson(Map<String, dynamic> json) {
+    return GetOffsetResult(
+      dx: json['dx'],
+      dy: json['dy'],
+    );
+  }
+
+  @override
+  Map<String, dynamic> toJson() => <String, double>{
+    'dx': dx,
+    'dy': dy,
+  };
+}

packages/flutter_driver/lib/src/driver/driver.dart

@@ -19,6 +19,7 @@ import '../common/error.dart';
 import '../common/find.dart';
 import '../common/frame_sync.dart';
 import '../common/fuchsia_compat.dart';
+import '../common/geometry.dart';
 import '../common/gesture.dart';
 import '../common/health.dart';
 import '../common/message.dart';
@@ -466,6 +467,37 @@ class FlutterDriver {
     await _sendCommand(WaitUntilNoTransientCallbacks(timeout: timeout));
   }
 
+  Future<DriverOffset> _getOffset(SerializableFinder finder, OffsetType type, { Duration timeout }) async {
+    final GetOffset command = GetOffset(finder, type, timeout: timeout);
+    final GetOffsetResult result = GetOffsetResult.fromJson(await _sendCommand(command));
+    return DriverOffset(result.dx, result.dy);
+  }
+
+  /// Returns the point at the top left of the widget identified by `finder`.
+  Future<DriverOffset> getTopLeft(SerializableFinder finder, { Duration timeout }) async {
+    return _getOffset(finder, OffsetType.topLeft, timeout: timeout);
+  }
+
+  /// Returns the point at the top right of the widget identified by `finder`.
+  Future<DriverOffset> getTopRight(SerializableFinder finder, { Duration timeout }) async {
+    return _getOffset(finder, OffsetType.topRight, timeout: timeout);
+  }
+
+  /// Returns the point at the bottom left of the widget identified by `finder`.
+  Future<DriverOffset> getBottomLeft(SerializableFinder finder, { Duration timeout }) async {
+    return _getOffset(finder, OffsetType.bottomLeft, timeout: timeout);
+  }
+
+  /// Returns the point at the bottom right of the widget identified by `finder`.
+  Future<DriverOffset> getBottomRight(SerializableFinder finder, { Duration timeout }) async {
+    return _getOffset(finder, OffsetType.bottomRight, timeout: timeout);
+  }
+
+  /// Returns the point at the center of the widget identified by `finder`.
+  Future<DriverOffset> getCenter(SerializableFinder finder, { Duration timeout }) async {
+    return _getOffset(finder, OffsetType.center, timeout: timeout);
+  }
+
   /// Tell the driver to perform a scrolling action.
   ///
   /// A scrolling action begins with a "pointer down" event, which commonly maps
@@ -986,3 +1018,29 @@ class CommonFinders {
   /// Finds the back button on a Material or Cupertino page's scaffold.
   SerializableFinder pageBack() => PageBack();
 }
+
+/// An immutable 2D floating-point offset used by Flutter Driver.
+class DriverOffset {
+  /// Creates an offset.
+  const DriverOffset(this.dx, this.dy);
+
+  /// The x component of the offset.
+  final double dx;
+
+  /// The y component of the offset.
+  final double dy;
+
+  @override
+  String toString() => '$runtimeType($dx, $dy)';
+
+  @override
+  bool operator ==(dynamic other) {
+    if (other is! DriverOffset)
+      return false;
+    final DriverOffset typedOther = other;
+    return dx == typedOther.dx && dy == typedOther.dy;
+  }
+
+  @override
+  int get hashCode => dx.hashCode + dy.hashCode;
+}

packages/flutter_driver/lib/src/extension/extension.dart

@@ -20,6 +20,7 @@ import 'package:flutter_test/flutter_test.dart';
 import '../common/error.dart';
 import '../common/find.dart';
 import '../common/frame_sync.dart';
+import '../common/geometry.dart';
 import '../common/gesture.dart';
 import '../common/health.dart';
 import '../common/message.dart';
@@ -112,6 +113,7 @@ class FlutterDriverExtension {
       'waitForAbsent': _waitForAbsent,
       'waitUntilNoTransientCallbacks': _waitUntilNoTransientCallbacks,
       'get_semantics_id': _getSemanticsId,
+      'get_offset': _getOffset,
     });
 
     _commandDeserializers.addAll(<String, CommandDeserializerCallback>{
@@ -130,6 +132,7 @@ class FlutterDriverExtension {
       'waitForAbsent': (Map<String, String> params) => WaitForAbsent.deserialize(params),
       'waitUntilNoTransientCallbacks': (Map<String, String> params) => WaitUntilNoTransientCallbacks.deserialize(params),
       'get_semantics_id': (Map<String, String> params) => GetSemanticsId.deserialize(params),
+      'get_offset': (Map<String, String> params) => GetOffset.deserialize(params),
     });
 
     _finders.addAll(<String, FinderConstructor>{
@@ -358,6 +361,33 @@ class FlutterDriverExtension {
     return GetSemanticsIdResult(node.id);
   }
 
+  Future<GetOffsetResult> _getOffset(Command command) async {
+    final GetOffset getOffsetCommand = command;
+    final Finder finder = await _waitForElement(_createFinder(getOffsetCommand.finder));
+    final Element element = finder.evaluate().single;
+    final RenderBox box = element.renderObject;
+    Offset localPoint;
+    switch (getOffsetCommand.offsetType) {
+      case OffsetType.topLeft:
+        localPoint = Offset.zero;
+        break;
+      case OffsetType.topRight:
+        localPoint = box.size.topRight(Offset.zero);
+        break;
+      case OffsetType.bottomLeft:
+        localPoint = box.size.bottomLeft(Offset.zero);
+        break;
+      case OffsetType.bottomRight:
+        localPoint = box.size.bottomRight(Offset.zero);
+        break;
+      case OffsetType.center:
+        localPoint = box.size.center(Offset.zero);
+        break;
+    }
+    final Offset globalPoint = box.localToGlobal(localPoint);
+    return GetOffsetResult(dx: globalPoint.dx, dy: globalPoint.dy);
+  }
+
   Future<ScrollResult> _scroll(Command command) async {
     final Scroll scrollCommand = command;
     final Finder target = await _waitForElement(_createFinder(scrollCommand.finder));

packages/flutter_driver/test/flutter_driver_test.dart

@@ -261,6 +261,111 @@ void main() {
       });
     });
 
+    group('getOffset', () {
+      test('requires a target reference', () async {
+        expect(driver.getCenter(null), throwsA(isInstanceOf<DriverError>()));
+        expect(driver.getTopLeft(null), throwsA(isInstanceOf<DriverError>()));
+        expect(driver.getTopRight(null), throwsA(isInstanceOf<DriverError>()));
+        expect(driver.getBottomLeft(null), throwsA(isInstanceOf<DriverError>()));
+        expect(driver.getBottomRight(null), throwsA(isInstanceOf<DriverError>()));
+      });
+
+      test('sends the getCenter command', () async {
+        when(mockIsolate.invokeExtension(any, any)).thenAnswer((Invocation i) {
+          expect(i.positionalArguments[1], <String, dynamic>{
+            'command': 'get_offset',
+            'offsetType': 'center',
+            'timeout': _kSerializedTestTimeout,
+            'finderType': 'ByValueKey',
+            'keyValueString': '123',
+            'keyValueType': 'int',
+          });
+          return makeMockResponse(<String, double>{
+            'dx': 11,
+            'dy': 12,
+          });
+        });
+        final DriverOffset result = await driver.getCenter(find.byValueKey(123), timeout: _kTestTimeout);
+        expect(result, const DriverOffset(11, 12));
+      });
+
+      test('sends the getTopLeft command', () async {
+        when(mockIsolate.invokeExtension(any, any)).thenAnswer((Invocation i) {
+          expect(i.positionalArguments[1], <String, dynamic>{
+            'command': 'get_offset',
+            'offsetType': 'topLeft',
+            'timeout': _kSerializedTestTimeout,
+            'finderType': 'ByValueKey',
+            'keyValueString': '123',
+            'keyValueType': 'int',
+          });
+          return makeMockResponse(<String, double>{
+            'dx': 11,
+            'dy': 12,
+          });
+        });
+        final DriverOffset result = await driver.getTopLeft(find.byValueKey(123), timeout: _kTestTimeout);
+        expect(result, const DriverOffset(11, 12));
+      });
+
+      test('sends the getTopRight command', () async {
+        when(mockIsolate.invokeExtension(any, any)).thenAnswer((Invocation i) {
+          expect(i.positionalArguments[1], <String, dynamic>{
+            'command': 'get_offset',
+            'offsetType': 'topRight',
+            'timeout': _kSerializedTestTimeout,
+            'finderType': 'ByValueKey',
+            'keyValueString': '123',
+            'keyValueType': 'int',
+          });
+          return makeMockResponse(<String, double>{
+            'dx': 11,
+            'dy': 12,
+          });
+        });
+        final DriverOffset result = await driver.getTopRight(find.byValueKey(123), timeout: _kTestTimeout);
+        expect(result, const DriverOffset(11, 12));
+      });
+
+      test('sends the getBottomLeft command', () async {
+        when(mockIsolate.invokeExtension(any, any)).thenAnswer((Invocation i) {
+          expect(i.positionalArguments[1], <String, dynamic>{
+            'command': 'get_offset',
+            'offsetType': 'bottomLeft',
+            'timeout': _kSerializedTestTimeout,
+            'finderType': 'ByValueKey',
+            'keyValueString': '123',
+            'keyValueType': 'int',
+          });
+          return makeMockResponse(<String, double>{
+            'dx': 11,
+            'dy': 12,
+          });
+        });
+        final DriverOffset result = await driver.getBottomLeft(find.byValueKey(123), timeout: _kTestTimeout);
+        expect(result, const DriverOffset(11, 12));
+      });
+
+      test('sends the getBottomRight command', () async {
+        when(mockIsolate.invokeExtension(any, any)).thenAnswer((Invocation i) {
+          expect(i.positionalArguments[1], <String, dynamic>{
+            'command': 'get_offset',
+            'offsetType': 'bottomRight',
+            'timeout': _kSerializedTestTimeout,
+            'finderType': 'ByValueKey',
+            'keyValueString': '123',
+            'keyValueType': 'int',
+          });
+          return makeMockResponse(<String, double>{
+            'dx': 11,
+            'dy': 12,
+          });
+        });
+        final DriverOffset result = await driver.getBottomRight(find.byValueKey(123), timeout: _kTestTimeout);
+        expect(result, const DriverOffset(11, 12));
+      });
+    });
+
     group('clearTimeline', () {
       test('clears timeline', () async {
         bool clearWasCalled = false;

packages/flutter_driver/test/src/extension_test.dart

@@ -6,6 +6,7 @@ import 'package:flutter/rendering.dart';
 import 'package:flutter/scheduler.dart';
 import 'package:flutter/widgets.dart';
 import 'package:flutter_driver/src/common/find.dart';
+import 'package:flutter_driver/src/common/geometry.dart';
 import 'package:flutter_driver/src/common/request_data.dart';
 import 'package:flutter_driver/src/extension/extension.dart';
 import 'package:flutter_test/flutter_test.dart';
@@ -120,4 +121,34 @@ void main() {
       semantics.dispose();
     });
   });
+
+  testWidgets('getOffset', (WidgetTester tester) async {
+    final FlutterDriverExtension extension = FlutterDriverExtension((String arg) async => '', true);
+
+    Future<Offset> getOffset(OffsetType offset) async {
+      final Map<String, Object> arguments = GetOffset(ByValueKey(1), offset).serialize();
+      final GetOffsetResult result = GetOffsetResult.fromJson((await extension.call(arguments))['response']);
+      return Offset(result.dx, result.dy);
+    }
+
+    await tester.pumpWidget(
+      Align(
+        alignment: Alignment.topLeft,
+        child: Transform.translate(
+          offset: const Offset(40, 30),
+          child: Container(
+            key: const ValueKey<int>(1),
+            width: 100,
+            height: 120,
+          ),
+        ),
+      ),
+    );
+
+    expect(await getOffset(OffsetType.topLeft), const Offset(40, 30));
+    expect(await getOffset(OffsetType.topRight), const Offset(40 + 100.0, 30));
+    expect(await getOffset(OffsetType.bottomLeft), const Offset(40, 30 + 120.0));
+    expect(await getOffset(OffsetType.bottomRight), const Offset(40 + 100.0, 30 + 120.0));
+    expect(await getOffset(OffsetType.center), const Offset(40 + (100 / 2), 30 + (120 / 2)));
+  });
 }