[syncfusion_flutter_pdfviewer] Out of Memory on large PDF Files

[francescovallone]

Bug description

When using the library on an iPad and attempting to load a large PDF file (300 MB), the application crashes or freezes completely.
The difference in behavior is related to the use of .file or .memory.

In both cases, the problem is related to the fact that the 300 MBs are instantly added to the heap stack, causing the application to run out of memory.

I also tried to stream the content of the file to the viewer but it failed miserably 😢

Steps to reproduce

Use .file or .memory named constructor to create a PdfViewer and load a large file (300MB)

Code sample

Code sample

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Screenshots or Video

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Stack Traces

Stack Traces

On which target platforms have you observed this bug?

iOS, Android

Flutter Doctor output

Doctor output

Doctor summary (to see all details, run flutter doctor -v):
[✓] Flutter (Channel stable, 3.32.8, on macOS 15.4.1 24E263 darwin-arm64, locale it-IT)
[✓] Android toolchain - develop for Android devices (Android SDK version 35.0.0)
[✓] Xcode - develop for iOS and macOS (Xcode 16.3)
[✓] Chrome - develop for the web
[✓] Android Studio (version 2024.3)
[✓] VS Code (version 1.103.2)
[✓] Connected device (3 available)
[✓] Network resources

• No issues found!

[francescovallone]

Tested and found it also on Android

[immankumarsync]

@francescovallone, we suspect that the out-of-memory issues are specific to PDF documents. Could you please share the PDF document in which you noticed the memory issues? This will help us validate the case based on the type of documents being used.

[francescovallone]

@immankumarsync unfortunately I can't share the document. If you tell me how to analyze it to help you out I'm more than happy to do it

[immankumarsync]

Hi @francescovallone,
We have identified the cause of the out-of-memory issue when opening large PDF documents partially. When a PDF is loaded, the text from all pages is extracted in a separate isolate and cached for text search operations. Due to the large number of pages, this process consumes a significant amount of memory.
We have created a test patch that disables text extraction. Could you please try this patch with the PDF document where the issue occurs and let us know if you're able to open it without encountering the out-of-memory error?

Please use the below dependency in the pubspec.yaml file,

syncfusion_flutter_pdfviewer:
  git:
    url: https://github.com/immankumarsync/flutter-widgets
    path: packages\syncfusion_flutter_pdfviewer
    ref: gh2433-linear-search

Please note that with this implementation, text search will be performed linearly and may be delayed in locating each instance of the searched text in a large document.

Regards,
Imman Kumar P

[francescovallone]

Hi @immankumarsync,
Thank you for your help. I tried to use it today on the same large file I had problem with in the beginning.
It doesn't crash anymore but unfortunately it doesn't load up either. The document calls the onDocumentLoadFailed callback.

The logs are the following:

Failed to load document: There was an error opening this document. - Error