Text is bouncing in TextFormField / TextField with multiline setting when typing in iOS, with Impeller on

[ringoswy]

Steps to reproduce

When typing in a TextFormField with multiline setting, text below the current line will bounce

Expected results

All text should not bounce

Actual results

Text below the current line will bounce

Code sample

Code sample

```dart import 'package:flutter/material.dart'; class Test extends StatefulWidget { const Test({super.key}); @override State createState() => _TestScreen(); } class _TestScreen extends State { @override Widget build(BuildContext context) { return Scaffold( body: Center( child: TextFormField( minLines: 5, maxLines: 10, )), ); } } ```

Screenshots or Video

Screenshots / Video demonstration

https://github.com/flutter/flutter/assets/32198138/c9307df8-a24e-4842-a0e3-e47bf31a186d

Logs

Logs

```console [Paste your logs here] ```

Flutter Doctor output

Doctor output

```console Doctor summary (to see all details, run flutter doctor -v): [✓] Flutter (Channel stable, 3.19.6, on macOS 14.3 23D56 darwin-arm64, locale en-HK) [✓] Android toolchain - develop for Android devices (Android SDK version 34.0.0) [✓] Xcode - develop for iOS and macOS (Xcode 15.3) [✓] Chrome - develop for the web [✓] Android Studio (version 2023.2) [✓] Connected device (3 available) [✓] Network resources • No issues found! ```

[darshankawar]

Thanks for the report. I was able to replicate this using latest versions. The reported behavior also occurs using TextField.

stable, master flutter doctor -v

``` [!] Flutter (Channel stable, 3.19.6, on macOS 12.2.1 21D62 darwin-x64, locale en-GB) • Flutter version 3.19.6 on channel stable at /Users/dhs/documents/fluttersdk/flutter ! Warning: `flutter` on your path resolves to /Users/dhs/Documents/Fluttersdk/flutter/bin/flutter, which is not inside your current Flutter SDK checkout at /Users/dhs/documents/fluttersdk/flutter. Consider adding /Users/dhs/documents/fluttersdk/flutter/bin to the front of your path. ! Warning: `dart` on your path resolves to /Users/dhs/Documents/Fluttersdk/flutter/bin/dart, which is not inside your current Flutter SDK checkout at /Users/dhs/documents/fluttersdk/flutter. Consider adding /Users/dhs/documents/fluttersdk/flutter/bin to the front of your path. • Upstream repository https://github.com/flutter/flutter.git • Framework revision 54e66469a9 (6 days ago), 2024-04-17 13:08:03 -0700 • Engine revision c4cd48e186 • Dart version 3.3.4 • DevTools version 2.31.1 • If those were intentional, you can disregard the above warnings; however it is recommended to use "git" directly to perform update checks and upgrades. [!] Xcode - develop for iOS and macOS (Xcode 12.3) • Xcode at /Applications/Xcode.app/Contents/Developer ! Flutter recommends a minimum Xcode version of 13. Download the latest version or update via the Mac App Store. • CocoaPods version 1.11.2 [✓] Chrome - develop for the web • Chrome at /Applications/Google Chrome.app/Contents/MacOS/Google Chrome [✓] VS Code (version 1.62.0) • VS Code at /Applications/Visual Studio Code.app/Contents • Flutter extension version 3.21.0 [✓] Connected device (5 available) • SM G975F (mobile) • RZ8M802WY0X • android-arm64 • Android 11 (API 30) • Darshan's iphone (mobile) • 21150b119064aecc249dfcfe05e259197461ce23 • ios • iOS 14.4.1 18D61 • iPhone 12 Pro Max (mobile) • A5473606-0213-4FD8-BA16-553433949729 • ios • com.apple.CoreSimulator.SimRuntime.iOS-14-3 (simulator) • macOS (desktop) • macos • darwin-x64 • Mac OS X 10.15.4 19E2269 darwin-x64 • Chrome (web) • chrome • web-javascript • Google Chrome 98.0.4758.80 [✓] HTTP Host Availability • All required HTTP hosts are available ! Doctor found issues in 1 category. [!] Flutter (Channel master, 3.22.0-18.0.pre.53, on macOS 12.2.1 21D62 darwin-x64, locale en-GB) • Flutter version 3.22.0-18.0.pre.53 on channel master at /Users/dhs/documents/fluttersdk/flutter ! Warning: `flutter` on your path resolves to /Users/dhs/Documents/Fluttersdk/flutter/bin/flutter, which is not inside your current Flutter SDK checkout at /Users/dhs/documents/fluttersdk/flutter. Consider adding /Users/dhs/documents/fluttersdk/flutter/bin to the front of your path. ! Warning: `dart` on your path resolves to /Users/dhs/Documents/Fluttersdk/flutter/bin/dart, which is not inside your current Flutter SDK checkout at /Users/dhs/documents/fluttersdk/flutter. Consider adding /Users/dhs/documents/fluttersdk/flutter/bin to the front of your path. • Upstream repository https://github.com/flutter/flutter.git • Framework revision 098e7e7ff3 (4 hours ago), 2024-04-29 01:25:19 +0000 • Engine revision 752b146df7 • Dart version 3.5.0 (build 3.5.0-109.0.dev) • DevTools version 2.35.0-dev.16 • 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 30.0.3) • Android SDK at /Users/dhs/Library/Android/sdk ✗ cmdline-tools component is missing Run `path/to/sdkmanager --install "cmdline-tools;latest"` See https://developer.android.com/studio/command-line for more details. ✗ Android license status unknown. Run `flutter doctor --android-licenses` to accept the SDK licenses. See https://flutter.dev/docs/get-started/install/macos#android-setup for more details. [✓] Xcode - develop for iOS and macOS (Xcode 13.2.1) • Xcode at /Applications/Xcode.app/Contents/Developer • Build 13C100 • CocoaPods version 1.11.2 [✓] Chrome - develop for the web • Chrome at /Applications/Google Chrome.app/Contents/MacOS/Google Chrome [✓] IntelliJ IDEA Ultimate Edition (version 2021.3.2) • IntelliJ at /Applications/IntelliJ IDEA.app • Flutter plugin version 65.1.4 • Dart plugin version 213.7228 [✓] VS Code (version 1.62.0) • VS Code at /Applications/Visual Studio Code.app/Contents • Flutter extension version 3.29.0 [✓] Connected device (3 available) • Darshan's iphone (mobile) • 21150b119064aecc249dfcfe05e259197461ce23 • ios • iOS 15.3.1 19D52 • macOS (desktop) • macos • darwin-x64 • macOS 12.2.1 21D62 darwin-x64 • Chrome (web) • chrome • web-javascript • Google Chrome 109.0.5414.119 [✓] Network resources • All expected network resources are available. ! Doctor found issues in 1 category. [!] Xcode - develop for iOS and macOS (Xcode 12.3) • Xcode at /Applications/Xcode.app/Contents/Developer ! Flutter recommends a minimum Xcode version of 13. Download the latest version or update via the Mac App Store. • CocoaPods version 1.11.2 [✓] Chrome - develop for the web • Chrome at /Applications/Google Chrome.app/Contents/MacOS/Google Chrome [✓] VS Code (version 1.62.0) • VS Code at /Applications/Visual Studio Code.app/Contents • Flutter extension version 3.21.0 [✓] Connected device (5 available) • SM G975F (mobile) • RZ8M802WY0X • android-arm64 • Android 11 (API 30) • Darshan's iphone (mobile) • 21150b119064aecc249dfcfe05e259197461ce23 • ios • iOS 14.4.1 18D61 • iPhone 12 Pro Max (mobile) • A5473606-0213-4FD8-BA16-553433949729 • ios • com.apple.CoreSimulator.SimRuntime.iOS-14-3 (simulator) • macOS (desktop) • macos • darwin-x64 • Mac OS X 10.15.4 19E2269 darwin-x64 • Chrome (web) • chrome • web-javascript • Google Chrome 98.0.4758.80 [✓] HTTP Host Availability • All required HTTP hosts are available ! Doctor found issues in 1 category. ```

[ringoswy]

Thanks a lot

[jmagman]

@ringoswy @darshankawar does this reproduce on Android?

If not, guessing it's a SKParagraph issue?

[ringoswy]

@ringoswy @darshankawar does this reproduce on Android?

If not, guessing it's a SKParagraph issue?

It doesn't happen on Android

[justinmc]

@jmagman I thought Android and iOS are both using SKParagraph?

[justinmc]

@jason-simmons Any idea by looking at that video if this is an SKParagraph issue or not?

[jason-simmons]

Both Android and iOS are using SkParagraph.

If this is currently only happening on iOS, then it is more likely to be related to Impeller glyph positioning.

[jmagman]

@ringoswy @darshankawar does this reproduce with Impeller off?

$ flutter run --no-enable-impeller

[ringoswy]

@ringoswy @darshankawar does this reproduce with Impeller off?

$ flutter run --no-enable-impeller

It doesn't reproduce with Impeller off