[web] Changing text size in runtime causes abnormal lineHeightScaleFactorOverride values. #178856
Description
Steps to reproduce
- Switch to
master - Run the provided example
- Change the browser's
Font sizesetting while the app is running - Observe the abnormal
lineHeightScaleFactorOverridevalue
Expected results
The lineHeightScaleFactorOverride value doesn't have to change when the user changes the font size.
Actual results
The lineHeightScaleFactorOverride value changes to abnormal when the user changes the font size.
Code sample
Code sample
import 'package:flutter/material.dart';
void main() {
runApp(const App());
}
class App extends StatelessWidget {
const App({super.key});
@override
Widget build(BuildContext context) {
return const MaterialApp(
debugShowCheckedModeBanner: false,
home: Screen(),
);
}
}
class Screen extends StatefulWidget {
const Screen({super.key});
@override
State<Screen> createState() => _ScreenState();
}
class _ScreenState extends State<Screen> with SingleTickerProviderStateMixin {
@override
Widget build(BuildContext context) {
return Scaffold(
body: Center(
child: Padding(
padding: const EdgeInsets.all(8),
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
spacing: 10,
children: [
Builder(
builder: (context) {
print(
'lineHeightScaleFactorOverride: ${MediaQuery.maybeLineHeightScaleFactorOverrideOf(context)}',
);
final scale = MediaQuery.textScalerOf(context).scale(1);
return Text(
'Scale ${scale.toStringAsFixed(3)}',
style: TextStyle(fontSize: 30),
textAlign: TextAlign.center,
);
},
),
],
),
),
),
);
}
}Screenshots or Video
Screenshots / Video demonstration
line_height_factor_override.mp4
Logs
Logs
[Paste your logs here]Flutter Doctor output
Doctor output
[!] Flutter (Channel [user-branch], 3.39.0-1.0.pre-205, on macOS 15.6.1 24G90 darwin-arm64, locale en-US) [210ms]
! Flutter version 3.39.0-1.0.pre-205 on channel [user-branch] at /Users/ksokolovskyi/development/flutter_master
Currently on an unknown channel. Run `flutter channel` to switch to an official channel.
If that doesn't fix the issue, reinstall Flutter by following instructions at https://flutter.dev/setup.
! Upstream repository unknown source is not the same as FLUTTER_GIT_URL
• FLUTTER_GIT_URL = [email protected]:ksokolovskyi/flutter.git
• Framework revision 3d01bf9a53 (18 hours ago), 2025-11-19 17:01:25 +0100
• Engine revision de4be4f389
• Dart version 3.11.0 (build 3.11.0-150.0.dev)
• DevTools version 2.52.0
• Feature flags: enable-web, enable-linux-desktop, enable-macos-desktop, enable-windows-desktop, enable-android, enable-ios, cli-animations,
enable-native-assets, omit-legacy-version-file, enable-lldb-debugging, enable-uiscene-migration
• If those were intentional, you can disregard the above warnings; however it is recommended to use "git" directly to perform update checks and upgrades.
[✓] Android toolchain - develop for Android devices (Android SDK version 36.0.0) [993ms]
• Android SDK at /Users/ksokolovskyi/Library/Android/sdk
• Emulator version 35.4.9.0 (build_id 13025442) (CL:N/A)
• Platform android-36, build-tools 36.0.0
• ANDROID_HOME = /Users/ksokolovskyi/Library/Android/sdk
• Java binary at: /Applications/Android Studio.app/Contents/jbr/Contents/Home/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 21.0.5+-13047016-b750.29)
• All Android licenses accepted.
[✓] Xcode - develop for iOS and macOS (Xcode 16.4) [754ms]
• Xcode at /Applications/Xcode.app/Contents/Developer
• Build 16F6
• CocoaPods version 1.16.2
[✓] Chrome - develop for the web [8ms]
• Chrome at /Applications/Google Chrome.app/Contents/MacOS/Google Chrome
[✓] Connected device (2 available) [5.9s]
• macOS (desktop) • macos • darwin-arm64 • macOS 15.6.1 24G90 darwin-arm64
• Chrome (web) • chrome • web-javascript • Google Chrome 142.0.7444.176
[✓] Network resources [305ms]
• All expected network resources are available.Metadata
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