[Impeller] Artefacts when drawing circle of non integer position with a ShaderMask #128353
Description
Is there an existing issue for this?
- I have searched the existing issues
- I have read the guide to filing a bug
Steps to reproduce
- Draw a circle offset by a fraction of a pixel inside of a
SharedMaskwidget - Run application on physical iOS device (observed on iPhone 14, iOS 16.5)
Expected results
Circle is precisely rendered.
Actual results
The circle is imprecisely rendered (visible on screenshots).
Works correctly with impeller disabled. All simpler cases (without 0.5px padding or without ShaderMask) work properly as well.
Code sample
Code sample
import 'package:flutter/material.dart';
void main() {
runApp(const MyApp());
}
class MyApp extends StatelessWidget {
const MyApp({super.key});
@override
Widget build(BuildContext context) => MaterialApp(
home: Scaffold(
body: Center(
child: SizedBox.square(
dimension: 100,
child: ShaderMask(
shaderCallback: (rect) => const LinearGradient(
colors: [
Colors.black,
Colors.transparent,
],
stops: [
0,
1,
],
).createShader(rect),
blendMode: BlendMode.dstOut,
child: const Padding(
padding: EdgeInsets.all(0.5),
child: DecoratedBox(
decoration: BoxDecoration(
shape: BoxShape.circle,
color: Colors.grey,
),
),
),
),
),
),
),
);
}
Screenshots or Video
Screenshots / Video demonstration
Logs
Logs
[Paste your logs here]Flutter Doctor output
Doctor output
[✓] Flutter (Channel stable, 3.10.3, on macOS 13.0.1 22A400 darwin-arm64, locale en-PL)
• Flutter version 3.10.3 on channel stable at /Users/robert/fvm/versions/3.10.3
• Upstream repository https://github.com/flutter/flutter.git
• Framework revision f92f44110e (5 days ago), 2023-06-01 18:17:33 -0500
• Engine revision 2a3401c9bb
• Dart version 3.0.3
• DevTools version 2.23.1
[✓] Android toolchain - develop for Android devices (Android SDK version 32.1.0-rc1)
• Android SDK at /Users/robert/Library/Android/sdk
• Platform android-33, build-tools 32.1.0-rc1
• Java binary at: /Applications/Android Studio.app/Contents/jre/Contents/Home/bin/java
• Java version OpenJDK Runtime Environment (build 11.0.13+0-b1751.21-8125866)
• All Android licenses accepted.
[✓] Xcode - develop for iOS and macOS (Xcode 14.2)
• Xcode at /Applications/Xcode 14.2.app/Contents/Developer
• Build 14C18
• CocoaPods version 1.12.1
[✓] Chrome - develop for the web
• Chrome at /Applications/Google Chrome.app/Contents/MacOS/Google Chrome
[✓] Android Studio (version 2021.3)
• Android Studio at /Applications/Android Studio.app/Contents
• Flutter plugin can be installed from:
🔨 https://plugins.jetbrains.com/plugin/9212-flutter
• Dart plugin can be installed from:
🔨 https://plugins.jetbrains.com/plugin/6351-dart
• Java version OpenJDK Runtime Environment (build 11.0.13+0-b1751.21-8125866)
[✓] VS Code (version 1.78.2)
• VS Code at /Applications/Visual Studio Code.app/Contents
• Flutter extension version 3.66.0
[✓] Connected device (4 available)
• Robert’s iPhone (mobile) • 00008110-000275E03ABA401E • ios • iOS
16.5 20F66
• iPhone 14 Pro Max (mobile) • 289D6742-D42F-4AA0-A767-036465059E0A • ios •
com.apple.CoreSimulator.SimRuntime.iOS-16-4 (simulator)
• macOS (desktop) • macos • darwin-arm64 • macOS
13.0.1 22A400 darwin-arm64
• Chrome (web) • chrome • web-javascript • Google
Chrome 113.0.5672.126
! Error: Robert’s iPhone is busy: Fetching debug symbols for Robert’s iPhone. Xcode will
continue when Robert’s iPhone is finished. (code -10)
[✓] Network resources
• All expected network resources are available.
• No issues found!