[syncfusion_flutter_pdfviewer] Pinch-to-zoom works only if you start first pinching with a single finger

[AlanJereb]

Bug description

In a multi-page PDF document, syncfusion_flutter_pdf's pinch-to-zoom will work only if you start "pinching" with one finger, and then the second one. If you try to pinch and zoom with both fingers simultaneously, zooming won't work.

Steps to reproduce

1. Open multi-page SfPdfViewer.file
2. Try pinch-to-zoom with both fingers at the same time

Code sample

Code sample

SfPdfViewer.file(
  File(item),
  maxZoomLevel: 20,
)

Screenshots or Video

Screenshots / Video demonstration

Stack Traces

There are no applicable stack traces. No exception is thrown.

On which target platforms have you observed this bug?

Android

Flutter Doctor output

Doctor output

[√] Flutter (Channel stable, 3.27.4, on Microsoft Windows [Version 10.0.19043.985], locale sl-SI)
    • Flutter version 3.27.4 on channel stable at C:\Users\alan.jereb\fvm\versions\3.27.4
    • Upstream repository https://github.com/flutter/flutter.git
    • Framework revision d8a9f9a52e (5 months ago), 2025-01-31 16:07:18 -0500
    • Engine revision 82bd5b7209
    • Dart version 3.6.2
    • DevTools version 2.40.3

[√] Windows Version (Installed version of Windows is version 10 or higher)

[√] Android toolchain - develop for Android devices (Android SDK version 33.0.1)
    • Android SDK at C:\Users\alan.jereb\AppData\Local\Android\Sdk        
    • Platform android-35, build-tools 33.0.1
    • ANDROID_HOME = C:\Users\alan.jereb\AppData\Local\Android\Sdk        
    • Java binary at: C:\Program Files\Android\Android Studio\jbr\bin\java
    • Java version OpenJDK Runtime Environment (build 17.0.11+0--11852314)
    • All Android licenses accepted.

[√] Chrome - develop for the web
    • Chrome at C:\Program Files\Google\Chrome\Application\chrome.exe

[√] Visual Studio - develop Windows apps (Visual Studio Community 2022 17.14.4)
    • Visual Studio at C:\Program Files\Microsoft Visual Studio\2022\Community
    • Visual Studio Community 2022 version 17.14.36202.13
    • Windows 10 SDK version 10.0.19041.0

[√] Android Studio (version 2024.1)
    • 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 17.0.11+0--11852314)

[√] VS Code, 64-bit edition (version 1.101.2)
    • VS Code at C:\Program Files\Microsoft VS Code
    • Flutter extension version 3.112.0

[√] Connected device (5 available)
    • SM A256B (mobile)            • R5CXB2LYVBZ   • android-arm64  • Android 14 (API 34)
    • sdk gphone64 x86 64 (mobile) • emulator-5554 • android-x64    • Android 14 (API 34) (emulator)
    • Windows (desktop)            • windows       • windows-x64    • Microsoft Windows [Version 10.0.19043.985]
    • Chrome (web)                 • chrome        • web-javascript • Google Chrome 138.0.7204.97
    • Edge (web)                   • edge          • web-javascript • Microsoft Edge 138.0.3351.55

[√] Network resources
    • All expected network resources are available.

• No issues found!

The same behaviour occurs both on a physical device and on the emulator.

[immankumarsync]

Hi @AlanJereb, we are unable to replicate the reported issue, as pinch-to-zoom is working as expected when initiated with two fingers simultaneously. Please find the attached video recording for your reference.

Could you kindly check this on a real device and let us know if you encounter the same issue there?

Screen.Recording.2025-07-02.161623.mp4

[AlanJereb]

Hi @AlanJereb, we are unable to replicate the reported issue, as pinch-to-zoom is working as expected when initiated with two fingers simultaneously. Please find the attached video recording for your reference.

Could you kindly check this on a real device and let us know if you encounter the same issue there?
Screen.Recording.2025-07-02.161623.mp4

We have tested it on two physical devices. Same issue as described above.

Here is a recording of the physical test on a Samsung sm-a256b:

studio64_fyXWykQlRD.mp4

There are no errors in the output.

Plugin version:
syncfusion_flutter_pdfviewer: ^29.1.33

[immankumarsync]

@AlanJereb, we have tested this case on the Samsung G781B device, and we didn't face the reported issue. Please find the video recording below for reference. Could you please share a simple sample in which the issue replicates? This will be helpful for us to replicate the issue on our end and provide you with a prompt solution at the earliest.

Screen.Recording.2025-07-03.185731.mp4