[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!