packages/flutter/test/widgets/slotted_render_object_widget_test.dart - mirrors/flutter - Git at Google

 // Copyright 2014 The Flutter 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/foundation.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter/rendering.dart';
 import 'package:flutter/widgets.dart';
 import 'package:flutter_test/flutter_test.dart';

 import '../rendering/mock_canvas.dart';

 const Color green = Color(0xFF00FF00);
 const Color yellow = Color(0xFFFFFF00);

 void main() {
   testWidgets('SlottedRenderObjectWidget test', (WidgetTester tester) async {
     await tester.pumpWidget(buildWidget(
       topLeft: Container(
         height: 100,
         width: 80,
         color: yellow,
         child: const Text('topLeft'),
       ),
       bottomRight: Container(
         height: 120,
         width: 110,
         color: green,
         child: const Text('bottomRight'),
       ),
     ));

     expect(find.text('topLeft'), findsOneWidget);
     expect(find.text('bottomRight'), findsOneWidget);
     expect(tester.getSize(find.byType(_Diagonal)), const Size(80 + 110, 100 + 120));
     expect(find.byType(_Diagonal), paints
       ..rect(
         rect: const Rect.fromLTWH(0, 0, 80, 100),
         color: yellow,
       )
       ..rect(
         rect: const Rect.fromLTWH(80, 100, 110, 120),
         color: green,
       )
     );

     await tester.pumpWidget(buildWidget(
       topLeft: Container(
         height: 200,
         width: 100,
         color: yellow,
         child: const Text('topLeft'),
       ),
       bottomRight: Container(
         height: 220,
         width: 210,
         color: green,
         child: const Text('bottomRight'),
       ),
     ));

     expect(find.text('topLeft'), findsOneWidget);
     expect(find.text('bottomRight'), findsOneWidget);
     expect(tester.getSize(find.byType(_Diagonal)), const Size(100 + 210, 200 + 220));
     expect(find.byType(_Diagonal), paints
       ..rect(
         rect: const Rect.fromLTWH(0, 0, 100, 200),
         color: yellow,
       )
       ..rect(
         rect: const Rect.fromLTWH(100, 200, 210, 220),
         color: green,
       )
     );

     await tester.pumpWidget(buildWidget(
       topLeft: Container(
         height: 200,
         width: 100,
         color: yellow,
         child: const Text('topLeft'),
       ),
       bottomRight: Container(
         key: UniqueKey(),
         height: 230,
         width: 220,
         color: green,
         child: const Text('bottomRight'),
       ),
     ));

     expect(find.text('topLeft'), findsOneWidget);
     expect(find.text('bottomRight'), findsOneWidget);
     expect(tester.getSize(find.byType(_Diagonal)), const Size(100 + 220, 200 + 230));
     expect(find.byType(_Diagonal), paints
       ..rect(
         rect: const Rect.fromLTWH(0, 0, 100, 200),
         color: yellow,
       )
       ..rect(
         rect: const Rect.fromLTWH(100, 200, 220, 230),
         color: green,
       )
     );

     await tester.pumpWidget(buildWidget(
       topLeft: Container(
         height: 200,
         width: 100,
         color: yellow,
         child: const Text('topLeft'),
       ),
     ));

     expect(find.text('topLeft'), findsOneWidget);
     expect(find.text('bottomRight'), findsNothing);
     expect(tester.getSize(find.byType(_Diagonal)), const Size(100, 200));
     expect(find.byType(_Diagonal), paints
       ..rect(
         rect: const Rect.fromLTWH(0, 0, 100, 200),
         color: yellow,
       )
     );

     await tester.pumpWidget(buildWidget());
     expect(find.text('topLeft'), findsNothing);
     expect(find.text('bottomRight'), findsNothing);
     expect(tester.getSize(find.byType(_Diagonal)), Size.zero);
     expect(find.byType(_Diagonal), paintsNothing);

     await tester.pumpWidget(Container());
     expect(find.byType(_Diagonal), findsNothing);
   });

   test('nameForSlot', () {
     expect(_RenderDiagonal().publicNameForSlot(_DiagonalSlot.bottomRight), 'bottomRight');
     expect(_RenderDiagonal().publicNameForSlot(_DiagonalSlot.topLeft), 'topLeft');
     final _Slot slot = _Slot();
     expect(_RenderTest().publicNameForSlot(slot), slot.toString());
   });

   testWidgets('key reparenting', (WidgetTester tester) async {
     const Widget widget1 = SizedBox(key: ValueKey<String>('smol'), height: 10, width: 10);
     const Widget widget2 = SizedBox(key: ValueKey<String>('big'), height: 100, width: 100);
     const Widget nullWidget = SizedBox(key: ValueKey<String>('null'), height: 50, width: 50);

     await tester.pumpWidget(buildWidget(topLeft: widget1, bottomRight: widget2, nullSlot: nullWidget));
     final _RenderDiagonal renderObject = tester.renderObject(find.byType(_Diagonal));
     expect(renderObject._topLeft!.size, const Size(10, 10));
     expect(renderObject._bottomRight!.size, const Size(100, 100));
     expect(renderObject._nullSlot!.size, const Size(50, 50));

     final Element widget1Element = tester.element(find.byWidget(widget1));
     final Element widget2Element = tester.element(find.byWidget(widget2));
     final Element nullWidgetElement = tester.element(find.byWidget(nullWidget));

     // Swapping 1 and 2.
     await tester.pumpWidget(buildWidget(topLeft: widget2, bottomRight: widget1, nullSlot: nullWidget));
     expect(renderObject._topLeft!.size, const Size(100, 100));
     expect(renderObject._bottomRight!.size, const Size(10, 10));
     expect(renderObject._nullSlot!.size, const Size(50, 50));
     expect(widget1Element, same(tester.element(find.byWidget(widget1))));
     expect(widget2Element, same(tester.element(find.byWidget(widget2))));
     expect(nullWidgetElement, same(tester.element(find.byWidget(nullWidget))));

     // Shifting slots
     await tester.pumpWidget(buildWidget(topLeft: nullWidget, bottomRight: widget2, nullSlot: widget1));
     expect(renderObject._topLeft!.size, const Size(50, 50));
     expect(renderObject._bottomRight!.size, const Size(100, 100));
     expect(renderObject._nullSlot!.size, const Size(10, 10));
     expect(widget1Element, same(tester.element(find.byWidget(widget1))));
     expect(widget2Element, same(tester.element(find.byWidget(widget2))));
     expect(nullWidgetElement, same(tester.element(find.byWidget(nullWidget))));

     // Moving + Deleting.
     await tester.pumpWidget(buildWidget(bottomRight: widget2));
     expect(renderObject._topLeft, null);
     expect(renderObject._bottomRight!.size, const Size(100, 100));
     expect(renderObject._nullSlot, null);
     expect(widget1Element.debugIsDefunct, isTrue);
     expect(nullWidgetElement.debugIsDefunct, isTrue);
     expect(widget2Element, same(tester.element(find.byWidget(widget2))));

     // Moving.
     await tester.pumpWidget(buildWidget(topLeft: widget2));
     expect(renderObject._topLeft!.size, const Size(100, 100));
     expect(renderObject._bottomRight, null);
     expect(widget2Element, same(tester.element(find.byWidget(widget2))));
   });

   testWidgets('duplicated key error message', (WidgetTester tester) async {
     const Widget widget1 = SizedBox(key: ValueKey<String>('widget 1'), height: 10, width: 10);
     const Widget widget2 = SizedBox(key: ValueKey<String>('widget 1'), height: 100, width: 100);
     const Widget widget3 = SizedBox(key: ValueKey<String>('widget 1'), height: 50, width: 50);

     await tester.pumpWidget(buildWidget(topLeft: widget1, bottomRight: widget2, nullSlot: widget3));

     expect((tester.takeException() as FlutterError).toString(), equalsIgnoringHashCodes(
      'Multiple widgets used the same key in _Diagonal.\n'
      "The key [<'widget 1'>] was used by multiple widgets. The offending widgets were:\n"
      "  - SizedBox-[<'widget 1'>](width: 50.0, height: 50.0, renderObject: RenderConstrainedBox#00000 NEEDS-LAYOUT NEEDS-PAINT)\n"
      "  - SizedBox-[<'widget 1'>](width: 10.0, height: 10.0, renderObject: RenderConstrainedBox#00000 NEEDS-LAYOUT NEEDS-PAINT)\n"
      "  - SizedBox-[<'widget 1'>](width: 100.0, height: 100.0, renderObject: RenderConstrainedBox#a4685 NEEDS-LAYOUT NEEDS-PAINT)\n"
      'A key can only be specified on one widget at a time in the same parent widget.'
     ));
   });

   testWidgets('debugDescribeChildren', (WidgetTester tester) async {
     await tester.pumpWidget(buildWidget(
       topLeft: const SizedBox(
         height: 100,
         width: 80,
       ),
       bottomRight: const SizedBox(
         height: 120,
         width: 110,
       ),
     ));

     expect(
       tester.renderObject(find.byType(_Diagonal)).toStringDeep(),
       equalsIgnoringHashCodes(
         '_RenderDiagonal#00000 relayoutBoundary=up1\n'
         ' │ creator: _Diagonal ← Align ← Directionality ← MediaQuery ←\n'
         ' │   _MediaQueryFromView ← _PipelineOwnerScope ← _ViewScope ←\n'
         ' │   _RawView-[_DeprecatedRawViewKey TestFlutterView#00000] ← View ←\n'
         ' │   [root]\n'
         ' │ parentData: offset=Offset(0.0, 0.0) (can use size)\n'
         ' │ constraints: BoxConstraints(0.0<=w<=800.0, 0.0<=h<=600.0)\n'
         ' │ size: Size(190.0, 220.0)\n'
         ' │\n'
         ' ├─topLeft: RenderConstrainedBox#00000 relayoutBoundary=up2\n'
         ' │   creator: SizedBox ← _Diagonal ← Align ← Directionality ←\n'
         ' │     MediaQuery ← _MediaQueryFromView ← _PipelineOwnerScope ←\n'
         ' │     _ViewScope ← _RawView-[_DeprecatedRawViewKey\n'
         ' │     TestFlutterView#00000] ← View ← [root]\n'
         ' │   parentData: offset=Offset(0.0, 0.0) (can use size)\n'
         ' │   constraints: BoxConstraints(unconstrained)\n'
         ' │   size: Size(80.0, 100.0)\n'
         ' │   additionalConstraints: BoxConstraints(w=80.0, h=100.0)\n'
         ' │\n'
         ' └─bottomRight: RenderConstrainedBox#00000 relayoutBoundary=up2\n'
         '     creator: SizedBox ← _Diagonal ← Align ← Directionality ←\n'
         '       MediaQuery ← _MediaQueryFromView ← _PipelineOwnerScope ←\n'
         '       _ViewScope ← _RawView-[_DeprecatedRawViewKey\n'
         '       TestFlutterView#00000] ← View ← [root]\n'
         '     parentData: offset=Offset(80.0, 100.0) (can use size)\n'
         '     constraints: BoxConstraints(unconstrained)\n'
         '     size: Size(110.0, 120.0)\n'
         '     additionalConstraints: BoxConstraints(w=110.0, h=120.0)\n',
       )
     );
   });
 }

 Widget buildWidget({Widget? topLeft, Widget? bottomRight, Widget? nullSlot}) {
   return Directionality(
     textDirection: TextDirection.ltr,
     child: Align(
       alignment: Alignment.topLeft,
       child: _Diagonal(
         topLeft: topLeft,
         bottomRight: bottomRight,
         nullSlot: nullSlot,
       ),
     ),
   );
 }

 enum _DiagonalSlot {
   topLeft,
   bottomRight,
 }

 class _Diagonal extends RenderObjectWidget with SlottedMultiChildRenderObjectWidgetMixin<_DiagonalSlot?, RenderBox> {
   const _Diagonal({
     this.topLeft,
     this.bottomRight,
     this.nullSlot,
   });

   final Widget? topLeft;
   final Widget? bottomRight;
   final Widget? nullSlot;

   @override
   Iterable<_DiagonalSlot?> get slots => <_DiagonalSlot?>[null, ..._DiagonalSlot.values];

   @override
   Widget? childForSlot(_DiagonalSlot? slot) {
     switch (slot) {
       case null:
         return nullSlot;
       case _DiagonalSlot.topLeft:
         return topLeft;
       case _DiagonalSlot.bottomRight:
         return bottomRight;
     }
   }

   @override
   SlottedContainerRenderObjectMixin<_DiagonalSlot?, RenderBox> createRenderObject(
     BuildContext context,
   ) {
     return _RenderDiagonal();
   }
 }

 class _RenderDiagonal extends RenderBox with SlottedContainerRenderObjectMixin<_DiagonalSlot?, RenderBox> {
   RenderBox? get _topLeft => childForSlot(_DiagonalSlot.topLeft);
   RenderBox? get _bottomRight => childForSlot(_DiagonalSlot.bottomRight);
   RenderBox? get _nullSlot => childForSlot(null);

   @override
   void performLayout() {
     const BoxConstraints childConstraints = BoxConstraints();

     Size topLeftSize = Size.zero;
     if (_topLeft != null) {
       _topLeft!.layout(childConstraints, parentUsesSize: true);
       _positionChild(_topLeft!, Offset.zero);
       topLeftSize = _topLeft!.size;
     }

     Size bottomRightSize = Size.zero;
     if (_bottomRight != null) {
       _bottomRight!.layout(childConstraints, parentUsesSize: true);
       _positionChild(
         _bottomRight!,
         Offset(topLeftSize.width, topLeftSize.height),
       );
       bottomRightSize = _bottomRight!.size;
     }

     Size nullSlotSize = Size.zero;
     final RenderBox? nullSlot = _nullSlot;
     if (nullSlot != null) {
       nullSlot.layout(childConstraints, parentUsesSize: true);
       _positionChild(nullSlot, Offset.zero);
       nullSlotSize = nullSlot.size;
     }

     size = constraints.constrain(Size(
       topLeftSize.width + bottomRightSize.width + nullSlotSize.width,
       topLeftSize.height + bottomRightSize.height + nullSlotSize.height,
     ));
   }

   void _positionChild(RenderBox child, Offset offset) {
     (child.parentData! as BoxParentData).offset = offset;
   }

   @override
   void paint(PaintingContext context, Offset offset) {
     if (_topLeft != null) {
       _paintChild(_topLeft!, context, offset);
     }
     if (_bottomRight != null) {
       _paintChild(_bottomRight!, context, offset);
     }
   }

   void _paintChild(RenderBox child, PaintingContext context, Offset offset) {
     final BoxParentData childParentData = child.parentData! as BoxParentData;
     context.paintChild(child, childParentData.offset + offset);
   }

   String publicNameForSlot(_DiagonalSlot slot) => debugNameForSlot(slot);
 }

 class _Slot {
   @override
   String toString() => describeIdentity(this);
 }

 class _RenderTest extends RenderBox with SlottedContainerRenderObjectMixin<_Slot, RenderBox> {
   String publicNameForSlot(_Slot slot) => debugNameForSlot(slot);
 }
	// Copyright 2014 The Flutter 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/foundation.dart';
	import 'package:flutter/material.dart';
	import 'package:flutter/rendering.dart';
	import 'package:flutter/widgets.dart';
	import 'package:flutter_test/flutter_test.dart';

	import '../rendering/mock_canvas.dart';

	const Color green = Color(0xFF00FF00);
	const Color yellow = Color(0xFFFFFF00);

	void main() {
	testWidgets('SlottedRenderObjectWidget test', (WidgetTester tester) async {
	await tester.pumpWidget(buildWidget(
	topLeft: Container(
	height: 100,
	width: 80,
	color: yellow,
	child: const Text('topLeft'),
	),
	bottomRight: Container(
	height: 120,
	width: 110,
	color: green,
	child: const Text('bottomRight'),
	),
	));

	expect(find.text('topLeft'), findsOneWidget);
	expect(find.text('bottomRight'), findsOneWidget);
	expect(tester.getSize(find.byType(_Diagonal)), const Size(80 + 110, 100 + 120));
	expect(find.byType(_Diagonal), paints
	..rect(
	rect: const Rect.fromLTWH(0, 0, 80, 100),
	color: yellow,
	)
	..rect(
	rect: const Rect.fromLTWH(80, 100, 110, 120),
	color: green,
	)
	);

	await tester.pumpWidget(buildWidget(
	topLeft: Container(
	height: 200,
	width: 100,
	color: yellow,
	child: const Text('topLeft'),
	),
	bottomRight: Container(
	height: 220,
	width: 210,
	color: green,
	child: const Text('bottomRight'),
	),
	));

	expect(find.text('topLeft'), findsOneWidget);
	expect(find.text('bottomRight'), findsOneWidget);
	expect(tester.getSize(find.byType(_Diagonal)), const Size(100 + 210, 200 + 220));
	expect(find.byType(_Diagonal), paints
	..rect(
	rect: const Rect.fromLTWH(0, 0, 100, 200),
	color: yellow,
	)
	..rect(
	rect: const Rect.fromLTWH(100, 200, 210, 220),
	color: green,
	)
	);

	await tester.pumpWidget(buildWidget(
	topLeft: Container(
	height: 200,
	width: 100,
	color: yellow,
	child: const Text('topLeft'),
	),
	bottomRight: Container(
	key: UniqueKey(),
	height: 230,
	width: 220,
	color: green,
	child: const Text('bottomRight'),
	),
	));

	expect(find.text('topLeft'), findsOneWidget);
	expect(find.text('bottomRight'), findsOneWidget);
	expect(tester.getSize(find.byType(_Diagonal)), const Size(100 + 220, 200 + 230));
	expect(find.byType(_Diagonal), paints
	..rect(
	rect: const Rect.fromLTWH(0, 0, 100, 200),
	color: yellow,
	)
	..rect(
	rect: const Rect.fromLTWH(100, 200, 220, 230),
	color: green,
	)
	);

	await tester.pumpWidget(buildWidget(
	topLeft: Container(
	height: 200,
	width: 100,
	color: yellow,
	child: const Text('topLeft'),
	),
	));

	expect(find.text('topLeft'), findsOneWidget);
	expect(find.text('bottomRight'), findsNothing);
	expect(tester.getSize(find.byType(_Diagonal)), const Size(100, 200));
	expect(find.byType(_Diagonal), paints
	..rect(
	rect: const Rect.fromLTWH(0, 0, 100, 200),
	color: yellow,
	)
	);

	await tester.pumpWidget(buildWidget());
	expect(find.text('topLeft'), findsNothing);
	expect(find.text('bottomRight'), findsNothing);
	expect(tester.getSize(find.byType(_Diagonal)), Size.zero);
	expect(find.byType(_Diagonal), paintsNothing);

	await tester.pumpWidget(Container());
	expect(find.byType(_Diagonal), findsNothing);
	});

	test('nameForSlot', () {
	expect(_RenderDiagonal().publicNameForSlot(_DiagonalSlot.bottomRight), 'bottomRight');
	expect(_RenderDiagonal().publicNameForSlot(_DiagonalSlot.topLeft), 'topLeft');
	final _Slot slot = _Slot();
	expect(_RenderTest().publicNameForSlot(slot), slot.toString());
	});

	testWidgets('key reparenting', (WidgetTester tester) async {
	const Widget widget1 = SizedBox(key: ValueKey<String>('smol'), height: 10, width: 10);
	const Widget widget2 = SizedBox(key: ValueKey<String>('big'), height: 100, width: 100);
	const Widget nullWidget = SizedBox(key: ValueKey<String>('null'), height: 50, width: 50);

	await tester.pumpWidget(buildWidget(topLeft: widget1, bottomRight: widget2, nullSlot: nullWidget));
	final _RenderDiagonal renderObject = tester.renderObject(find.byType(_Diagonal));
	expect(renderObject._topLeft!.size, const Size(10, 10));
	expect(renderObject._bottomRight!.size, const Size(100, 100));
	expect(renderObject._nullSlot!.size, const Size(50, 50));

	final Element widget1Element = tester.element(find.byWidget(widget1));
	final Element widget2Element = tester.element(find.byWidget(widget2));
	final Element nullWidgetElement = tester.element(find.byWidget(nullWidget));

	// Swapping 1 and 2.
	await tester.pumpWidget(buildWidget(topLeft: widget2, bottomRight: widget1, nullSlot: nullWidget));
	expect(renderObject._topLeft!.size, const Size(100, 100));
	expect(renderObject._bottomRight!.size, const Size(10, 10));
	expect(renderObject._nullSlot!.size, const Size(50, 50));
	expect(widget1Element, same(tester.element(find.byWidget(widget1))));
	expect(widget2Element, same(tester.element(find.byWidget(widget2))));
	expect(nullWidgetElement, same(tester.element(find.byWidget(nullWidget))));

	// Shifting slots
	await tester.pumpWidget(buildWidget(topLeft: nullWidget, bottomRight: widget2, nullSlot: widget1));
	expect(renderObject._topLeft!.size, const Size(50, 50));
	expect(renderObject._bottomRight!.size, const Size(100, 100));
	expect(renderObject._nullSlot!.size, const Size(10, 10));
	expect(widget1Element, same(tester.element(find.byWidget(widget1))));
	expect(widget2Element, same(tester.element(find.byWidget(widget2))));
	expect(nullWidgetElement, same(tester.element(find.byWidget(nullWidget))));

	// Moving + Deleting.
	await tester.pumpWidget(buildWidget(bottomRight: widget2));
	expect(renderObject._topLeft, null);
	expect(renderObject._bottomRight!.size, const Size(100, 100));
	expect(renderObject._nullSlot, null);
	expect(widget1Element.debugIsDefunct, isTrue);
	expect(nullWidgetElement.debugIsDefunct, isTrue);
	expect(widget2Element, same(tester.element(find.byWidget(widget2))));

	// Moving.
	await tester.pumpWidget(buildWidget(topLeft: widget2));
	expect(renderObject._topLeft!.size, const Size(100, 100));
	expect(renderObject._bottomRight, null);
	expect(widget2Element, same(tester.element(find.byWidget(widget2))));
	});

	testWidgets('duplicated key error message', (WidgetTester tester) async {
	const Widget widget1 = SizedBox(key: ValueKey<String>('widget 1'), height: 10, width: 10);
	const Widget widget2 = SizedBox(key: ValueKey<String>('widget 1'), height: 100, width: 100);
	const Widget widget3 = SizedBox(key: ValueKey<String>('widget 1'), height: 50, width: 50);

	await tester.pumpWidget(buildWidget(topLeft: widget1, bottomRight: widget2, nullSlot: widget3));

	expect((tester.takeException() as FlutterError).toString(), equalsIgnoringHashCodes(
	'Multiple widgets used the same key in _Diagonal.\n'
	"The key [<'widget 1'>] was used by multiple widgets. The offending widgets were:\n"
	" - SizedBox-[<'widget 1'>](width: 50.0, height: 50.0, renderObject: RenderConstrainedBox#00000 NEEDS-LAYOUT NEEDS-PAINT)\n"
	" - SizedBox-[<'widget 1'>](width: 10.0, height: 10.0, renderObject: RenderConstrainedBox#00000 NEEDS-LAYOUT NEEDS-PAINT)\n"
	" - SizedBox-[<'widget 1'>](width: 100.0, height: 100.0, renderObject: RenderConstrainedBox#a4685 NEEDS-LAYOUT NEEDS-PAINT)\n"
	'A key can only be specified on one widget at a time in the same parent widget.'
	));
	});

	testWidgets('debugDescribeChildren', (WidgetTester tester) async {
	await tester.pumpWidget(buildWidget(
	topLeft: const SizedBox(
	height: 100,
	width: 80,
	),
	bottomRight: const SizedBox(
	height: 120,
	width: 110,
	),
	));

	expect(
	tester.renderObject(find.byType(_Diagonal)).toStringDeep(),
	equalsIgnoringHashCodes(
	'_RenderDiagonal#00000 relayoutBoundary=up1\n'
	' │ creator: _Diagonal ← Align ← Directionality ← MediaQuery ←\n'
	' │ _MediaQueryFromView ← _PipelineOwnerScope ← _ViewScope ←\n'
	' │ _RawView-[_DeprecatedRawViewKey TestFlutterView#00000] ← View ←\n'
	' │ [root]\n'
	' │ parentData: offset=Offset(0.0, 0.0) (can use size)\n'
	' │ constraints: BoxConstraints(0.0<=w<=800.0, 0.0<=h<=600.0)\n'
	' │ size: Size(190.0, 220.0)\n'
	' │\n'
	' ├─topLeft: RenderConstrainedBox#00000 relayoutBoundary=up2\n'
	' │ creator: SizedBox ← _Diagonal ← Align ← Directionality ←\n'
	' │ MediaQuery ← _MediaQueryFromView ← _PipelineOwnerScope ←\n'
	' │ _ViewScope ← _RawView-[_DeprecatedRawViewKey\n'
	' │ TestFlutterView#00000] ← View ← [root]\n'
	' │ parentData: offset=Offset(0.0, 0.0) (can use size)\n'
	' │ constraints: BoxConstraints(unconstrained)\n'
	' │ size: Size(80.0, 100.0)\n'
	' │ additionalConstraints: BoxConstraints(w=80.0, h=100.0)\n'
	' │\n'
	' └─bottomRight: RenderConstrainedBox#00000 relayoutBoundary=up2\n'
	' creator: SizedBox ← _Diagonal ← Align ← Directionality ←\n'
	' MediaQuery ← _MediaQueryFromView ← _PipelineOwnerScope ←\n'
	' _ViewScope ← _RawView-[_DeprecatedRawViewKey\n'
	' TestFlutterView#00000] ← View ← [root]\n'
	' parentData: offset=Offset(80.0, 100.0) (can use size)\n'
	' constraints: BoxConstraints(unconstrained)\n'
	' size: Size(110.0, 120.0)\n'
	' additionalConstraints: BoxConstraints(w=110.0, h=120.0)\n',
	)
	);
	});
	}

	Widget buildWidget({Widget? topLeft, Widget? bottomRight, Widget? nullSlot}) {
	return Directionality(
	textDirection: TextDirection.ltr,
	child: Align(
	alignment: Alignment.topLeft,
	child: _Diagonal(
	topLeft: topLeft,
	bottomRight: bottomRight,
	nullSlot: nullSlot,
	),
	),
	);
	}

	enum _DiagonalSlot {
	topLeft,
	bottomRight,
	}

	class _Diagonal extends RenderObjectWidget with SlottedMultiChildRenderObjectWidgetMixin<_DiagonalSlot?, RenderBox> {
	const _Diagonal({
	this.topLeft,
	this.bottomRight,
	this.nullSlot,
	});

	final Widget? topLeft;
	final Widget? bottomRight;
	final Widget? nullSlot;

	@override
	Iterable<_DiagonalSlot?> get slots => <_DiagonalSlot?>[null, ..._DiagonalSlot.values];

	@override
	Widget? childForSlot(_DiagonalSlot? slot) {
	switch (slot) {
	case null:
	return nullSlot;
	case _DiagonalSlot.topLeft:
	return topLeft;
	case _DiagonalSlot.bottomRight:
	return bottomRight;
	}
	}

	@override
	SlottedContainerRenderObjectMixin<_DiagonalSlot?, RenderBox> createRenderObject(
	BuildContext context,
	) {
	return _RenderDiagonal();
	}
	}

	class _RenderDiagonal extends RenderBox with SlottedContainerRenderObjectMixin<_DiagonalSlot?, RenderBox> {
	RenderBox? get _topLeft => childForSlot(_DiagonalSlot.topLeft);
	RenderBox? get _bottomRight => childForSlot(_DiagonalSlot.bottomRight);
	RenderBox? get _nullSlot => childForSlot(null);

	@override
	void performLayout() {
	const BoxConstraints childConstraints = BoxConstraints();

	Size topLeftSize = Size.zero;
	if (_topLeft != null) {
	_topLeft!.layout(childConstraints, parentUsesSize: true);
	_positionChild(_topLeft!, Offset.zero);
	topLeftSize = _topLeft!.size;
	}

	Size bottomRightSize = Size.zero;
	if (_bottomRight != null) {
	_bottomRight!.layout(childConstraints, parentUsesSize: true);
	_positionChild(
	_bottomRight!,
	Offset(topLeftSize.width, topLeftSize.height),
	);
	bottomRightSize = _bottomRight!.size;
	}

	Size nullSlotSize = Size.zero;
	final RenderBox? nullSlot = _nullSlot;
	if (nullSlot != null) {
	nullSlot.layout(childConstraints, parentUsesSize: true);
	_positionChild(nullSlot, Offset.zero);
	nullSlotSize = nullSlot.size;
	}

	size = constraints.constrain(Size(
	topLeftSize.width + bottomRightSize.width + nullSlotSize.width,
	topLeftSize.height + bottomRightSize.height + nullSlotSize.height,
	));
	}

	void _positionChild(RenderBox child, Offset offset) {
	(child.parentData! as BoxParentData).offset = offset;
	}

	@override
	void paint(PaintingContext context, Offset offset) {
	if (_topLeft != null) {
	_paintChild(_topLeft!, context, offset);
	}
	if (_bottomRight != null) {
	_paintChild(_bottomRight!, context, offset);
	}
	}

	void _paintChild(RenderBox child, PaintingContext context, Offset offset) {
	final BoxParentData childParentData = child.parentData! as BoxParentData;
	context.paintChild(child, childParentData.offset + offset);
	}

	String publicNameForSlot(_DiagonalSlot slot) => debugNameForSlot(slot);
	}

	class _Slot {
	@override
	String toString() => describeIdentity(this);
	}

	class _RenderTest extends RenderBox with SlottedContainerRenderObjectMixin<_Slot, RenderBox> {
	String publicNameForSlot(_Slot slot) => debugNameForSlot(slot);
	}