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[Impeller] When painting with a MaskFilter, subsequent calls to drawVertices use the same MaskFilter #170480
Description
Steps to reproduce
- Call canvas.drawRect with a Paint that uses a MaskFilter
- Call canvas.drawVertices with another paint that does not use a MaskFilter
- Run the app on Impeller (Skia doesn't have this issue)
Expected results
The rect is painted with a MaskFilter, the vertices are not.
Actual results
Both the rect and the vertices are painted with the same MaskFilter.
Code sample
I've added a Switch in the sample to toggle the MaskFilter, this way it's possible to verify that the filter is actually what's causing the issue.
Code sample
class MainApp extends StatefulWidget {
const MainApp({super.key});
@override
State<MainApp> createState() => _MainAppState();
}
class _MainAppState extends State<MainApp> {
bool renderShadow = true;
@override
Widget build(BuildContext context) {
return MaterialApp(
home: Scaffold(
body: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: [
SwitchListTile(
value: renderShadow,
onChanged: (value) => setState(() => renderShadow = value),
title: const Text('Render Shadow'),
),
CustomPaint(
painter: TwoRectsPainter(renderShadow: renderShadow),
size: Size(200, 200),
),
],
),
),
);
}
}
class TwoRectsPainter extends CustomPainter {
TwoRectsPainter({this.renderShadow = true});
final bool renderShadow;
@override
void paint(Canvas canvas, Size size) {
final paint1 = Paint()
..color = Colors.black45
..style = PaintingStyle.fill;
if (renderShadow) {
paint1.maskFilter = MaskFilter.blur(BlurStyle.outer, 10.0);
// Changing maskFilter to imageFilter fixes the issue.
// paint1.imageFilter = ImageFilter.blur(sigmaX: 10.0, sigmaY: 10.0);
}
final paint2 = Paint()
..color = Colors.red
..style = PaintingStyle.fill;
// First rectangle (top-left)
canvas.drawRect(Rect.fromLTWH(100, 80, 100, 80), paint1);
// Second rectangle (bottom-right)
canvas.drawVertices(createVertices(), BlendMode.dst, paint2);
}
Vertices createVertices() {
final vertices = Vertices.raw(
VertexMode.triangles,
Float32List.fromList([0, 0, 100, 0, 100, 80, 0, 0, 100, 80, 0, 80]),
);
return vertices;
}
@override
bool shouldRepaint(covariant CustomPainter oldDelegate) =>
oldDelegate is TwoRectsPainter &&
oldDelegate.renderShadow != renderShadow;
}Screenshots or Video
Screenshots / Video demonstration
| Expected result | Actual result |
|---|---|
 |
 |
Logs
Logs
Flutter Doctor output
Doctor output
[√] Flutter (Channel master, 3.33.0-1.0.pre.458, on Microsoft Windows [Version 10.0.26100.4061], locale en-150) [2.7s]
• Flutter version 3.33.0-1.0.pre.458 on channel master at C:\dev\flutter
• Upstream repository https://github.com/flutter/flutter.git
• Framework revision a4a2ef6d1e (2 hours ago), 2025-06-11 20:50:54 +0200
• Engine revision a4a2ef6d1e
• Dart version 3.9.0 (build 3.9.0-220.0.dev)
• DevTools version 2.48.0-dev.0
[√] Windows Version (11 Pro 64-bit, 24H2, 2009) [2.8s]
[√] Android toolchain - develop for Android devices (Android SDK version 35.0.0) [2.3s]
• Android SDK at C:\dev\AndroidSDK\
• Emulator version 35.2.10.0 (build_id 12414864) (CL:N/A)
• Platform android-36, build-tools 35.0.0
• Java binary at: C:\Program Files\Android\Android Studio\jbr\bin\java
This is the JDK bundled with the latest Android Studio installation on this machine.
To manually set the JDK path, use: `flutter config --jdk-dir="path/to/jdk"`.
• Java version OpenJDK Runtime Environment (build 21.0.3+-12282718-b509.11)
• All Android licenses accepted.
[√] Chrome - develop for the web [84ms]
• CHROME_EXECUTABLE = C:\Program Files\Google\Chrome Beta\Application\chrome.exe
[√] Visual Studio - develop Windows apps (Visual Studio Community 2022 17.12.3) [84ms]
• Visual Studio at C:\Program Files\Microsoft Visual Studio\2022\Community
• Visual Studio Community 2022 version 17.12.35527.113
• Windows 10 SDK version 10.0.22621.0
[√] Android Studio (version 2024.2) [16ms]
• Android Studio at C:\Program Files\Android\Android Studio
• 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 21.0.3+-12282718-b509.11)
[√] VS Code, 64-bit edition (version 1.100.2) [15ms]
• VS Code at C:\Program Files\Microsoft VS Code
• Flutter extension version 3.112.0
[√] Connected device (4 available) [302ms]
• sdk gphone64 x86 64 (mobile) • emulator-5554 • android-x64 • Android 15 (API 35) (emulator)
• Windows (desktop) • windows • windows-x64 • Microsoft Windows [Version 10.0.26100.4061]
• Chrome (web) • chrome • web-javascript • unknown
• Edge (web) • edge • web-javascript • Microsoft Edge 137.0.3296.68
[√] Network resources [572ms]
• All expected network resources are available.
• No issues found!
Activity
tirth-patel-nc commentedon Jun 12, 2025
Triage Report
I was able to reproduce the issue using the provided code sample on the
stable (3.32.2)andmaster (3.33.0-1.0.pre.474)channels on Android & iOS.@luccasclezar, can you please check and confirm whether #167835 #152778 are related to your case?
luccasclezar commentedon Jun 12, 2025
@tirth-patel-nc Maybe the underlying issue is the same, I don't know enough about Impeller to be sure, but I don't think so.
None of the other issues have anything to do with drawVertices, which is the main part of this one.
jonahwilliams commentedon Jun 12, 2025
The bug here is actually that the mask filter is applying at all. It should skip the vertices.
[Impeller] fix mask filter application to Vertices. (#170548)
github-actions commentedon Jun 27, 2025
This thread has been automatically locked since there has not been any recent activity after it was closed. If you are still experiencing a similar issue, please open a new bug, including the output of
flutter doctor -vand a minimal reproduction of the issue.[Impeller] fix mask filter application to Vertices. (flutter#170548)
[Impeller] fix mask filter application to Vertices. (#170548)