// 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/rendering.dart'; import 'package:flutter_test/flutter_test.dart'; import 'rendering_tester.dart'; void main() { TestRenderingFlutterBinding.ensureInitialized(); test('Stack can layout with top, right, bottom, left 0.0', () { final RenderBox size = RenderConstrainedBox( additionalConstraints: BoxConstraints.tight(const Size(100.0, 100.0)), ); final RenderBox red = RenderDecoratedBox( decoration: const BoxDecoration( color: Color(0xFFFF0000), ), child: size, ); final RenderBox green = RenderDecoratedBox( decoration: const BoxDecoration( color: Color(0xFFFF0000), ), ); final RenderBox stack = RenderStack( textDirection: TextDirection.ltr, children: <RenderBox>[red, green], ); final StackParentData greenParentData = green.parentData! as StackParentData; greenParentData ..top = 0.0 ..right = 0.0 ..bottom = 0.0 ..left = 0.0; layout(stack, constraints: const BoxConstraints()); expect(stack.size.width, equals(100.0)); expect(stack.size.height, equals(100.0)); expect(red.size.width, equals(100.0)); expect(red.size.height, equals(100.0)); expect(green.size.width, equals(100.0)); expect(green.size.height, equals(100.0)); }); test('Stack can layout with no children', () { final RenderBox stack = RenderStack( textDirection: TextDirection.ltr, children: <RenderBox>[], ); layout(stack, constraints: BoxConstraints.tight(const Size(100.0, 100.0))); expect(stack.size.width, equals(100.0)); expect(stack.size.height, equals(100.0)); }); test('Stack respects clipBehavior', () { const BoxConstraints viewport = BoxConstraints(maxHeight: 100.0, maxWidth: 100.0); final TestClipPaintingContext context = TestClipPaintingContext(); // By default, clipBehavior should be Clip.none final RenderStack defaultStack = RenderStack(textDirection: TextDirection.ltr, children: <RenderBox>[box200x200]); layout(defaultStack, constraints: viewport, phase: EnginePhase.composite, onErrors: expectOverflowedErrors); defaultStack.paint(context, Offset.zero); expect(context.clipBehavior, equals(Clip.none)); for (final Clip clip in Clip.values) { final RenderBox child = box200x200; final RenderStack stack = RenderStack( textDirection: TextDirection.ltr, children: <RenderBox>[child], clipBehavior: clip, ); { // Make sure that the child is positioned so the stack will consider it as overflowed. final StackParentData parentData = child.parentData! as StackParentData; parentData.left = parentData.right = 0; } layout(stack, constraints: viewport, phase: EnginePhase.composite, onErrors: expectOverflowedErrors); context.paintChild(stack, Offset.zero); expect(context.clipBehavior, equals(clip)); } }); group('RenderIndexedStack', () { test('visitChildrenForSemantics only visits displayed child', () { final RenderBox child1 = RenderConstrainedBox( additionalConstraints: BoxConstraints.tight(const Size(100.0, 100.0)), ); final RenderBox child2 = RenderConstrainedBox( additionalConstraints: BoxConstraints.tight(const Size(100.0, 100.0)), ); final RenderBox child3 = RenderConstrainedBox( additionalConstraints: BoxConstraints.tight(const Size(100.0, 100.0)), ); final RenderBox stack = RenderIndexedStack( index: 1, textDirection: TextDirection.ltr, children: <RenderBox>[child1, child2, child3], ); final List<RenderObject> visitedChildren = <RenderObject>[]; void visitor(RenderObject child) { visitedChildren.add(child); } stack.visitChildrenForSemantics(visitor); expect(visitedChildren, hasLength(1)); expect(visitedChildren.first, child2); }); test('debugDescribeChildren marks invisible children as offstage', () { final RenderBox child1 = RenderConstrainedBox( additionalConstraints: BoxConstraints.tight(const Size(100.0, 100.0)), ); final RenderBox child2 = RenderConstrainedBox( additionalConstraints: BoxConstraints.tight(const Size(100.0, 100.0)), ); final RenderBox child3 = RenderConstrainedBox( additionalConstraints: BoxConstraints.tight(const Size(100.0, 100.0)), ); final RenderBox stack = RenderIndexedStack( index: 2, children: <RenderBox>[child1, child2, child3], ); final List<DiagnosticsNode> diagnosticNodes = stack.debugDescribeChildren(); expect(diagnosticNodes[0].name, 'child 1'); expect(diagnosticNodes[0].style, DiagnosticsTreeStyle.offstage); expect(diagnosticNodes[1].name, 'child 2'); expect(diagnosticNodes[1].style, DiagnosticsTreeStyle.offstage); expect(diagnosticNodes[2].name, 'child 3'); expect(diagnosticNodes[2].style, DiagnosticsTreeStyle.sparse); }); }); test('Stack in Flex can layout with no children', () { // Render an empty Stack in a Flex final RenderFlex flex = RenderFlex( textDirection: TextDirection.ltr, mainAxisAlignment: MainAxisAlignment.spaceEvenly, children: <RenderBox>[ RenderStack( textDirection: TextDirection.ltr, children: <RenderBox>[], ), ] ); bool stackFlutterErrorThrown = false; layout( flex, constraints: BoxConstraints.tight(const Size(100.0, 100.0)), onErrors: () { stackFlutterErrorThrown = true; } ); expect(stackFlutterErrorThrown, false); }); // More tests in ../widgets/stack_test.dart }