Unverified Commit d19047d8 authored by Jonah Williams's avatar Jonah Williams Committed by GitHub

[framework] make opacity widget create a repaint boundary (#116788)

parent 5a229e28
......@@ -890,6 +890,9 @@ class RenderOpacity extends RenderProxyBox {
@override
bool get alwaysNeedsCompositing => child != null && _alpha > 0;
@override
bool get isRepaintBoundary => alwaysNeedsCompositing;
int _alpha;
/// The fraction to scale the child's alpha value.
......@@ -917,7 +920,7 @@ class RenderOpacity extends RenderProxyBox {
if (didNeedCompositing != alwaysNeedsCompositing) {
markNeedsCompositingBitsUpdate();
}
markNeedsPaint();
markNeedsCompositedLayerUpdate();
if (wasVisible != (_alpha != 0) && !alwaysIncludeSemantics) {
markNeedsSemanticsUpdate();
}
......@@ -944,23 +947,19 @@ class RenderOpacity extends RenderProxyBox {
return _alpha > 0;
}
@override
OffsetLayer updateCompositedLayer({required covariant OpacityLayer? oldLayer}) {
final OpacityLayer layer = oldLayer ?? OpacityLayer();
layer.alpha = _alpha;
return layer;
}
@override
void paint(PaintingContext context, Offset offset) {
if (child == null) {
return;
}
if (_alpha == 0) {
// No need to keep the layer. We'll create a new one if necessary.
layer = null;
if (child == null || _alpha == 0) {
return;
}
assert(needsCompositing);
layer = context.pushOpacity(offset, _alpha, super.paint, oldLayer: layer as OpacityLayer?);
assert(() {
layer!.debugCreator = debugCreator;
return true;
}());
super.paint(context, offset);
}
@override
......
// 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/material.dart';
import 'package:flutter/rendering.dart';
import 'package:flutter_test/flutter_test.dart';
void main() {
testWidgets('RenderOpacity avoids repainting and does not drop layer at fully opaque', (WidgetTester tester) async {
RenderTestObject.paintCount = 0;
await tester.pumpWidget(
Container(
color: Colors.red,
child: const Opacity(
opacity: 0.0,
child: TestWidget(),
),
)
);
expect(RenderTestObject.paintCount, 0);
await tester.pumpWidget(
Container(
color: Colors.red,
child: const Opacity(
opacity: 0.1,
child: TestWidget(),
),
)
);
expect(RenderTestObject.paintCount, 1);
await tester.pumpWidget(
Container(
color: Colors.red,
child: const Opacity(
opacity: 1,
child: TestWidget(),
),
)
);
expect(RenderTestObject.paintCount, 1);
});
testWidgets('RenderOpacity allows opacity layer to be dropped at 0 opacity', (WidgetTester tester) async {
RenderTestObject.paintCount = 0;
await tester.pumpWidget(
Container(
color: Colors.red,
child: const Opacity(
opacity: 0.5,
child: TestWidget(),
),
)
);
expect(RenderTestObject.paintCount, 1);
await tester.pumpWidget(
Container(
color: Colors.red,
child: const Opacity(
opacity: 0.0,
child: TestWidget(),
),
)
);
expect(RenderTestObject.paintCount, 1);
expect(tester.layers, isNot(contains(isA<OpacityLayer>())));
});
}
class TestWidget extends SingleChildRenderObjectWidget {
const TestWidget({super.key, super.child});
@override
RenderObject createRenderObject(BuildContext context) {
return RenderTestObject();
}
}
class RenderTestObject extends RenderProxyBox {
static int paintCount = 0;
@override
void paint(PaintingContext context, Offset offset) {
paintCount += 1;
super.paint(context, offset);
}
}
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