Strange behavior with the PDF Viewer

DeletedUser592

Hi there!

So I am experiencing strange behavior when opening large PDF files with the built-in PDF Viewer.

When I open a PDF magazine with several hundred pages (but 80MB to 200MB of size), the viewer starts to lag after a few pages. More surprisingly, it appears to cause Molly to crash silently (no error message).

I noticed this because I use Molly with WebSockets instead of UnifiedPush. Each time Molly restarts, I receive a notification indicating that WebSockets is ready to receive messages again. This happens consistently when I spend more than ~ 2 minutes in the PDF Viewer reading my magazine.

The PDF Viewer itself also crashes occasionally (with also no error message).

Additional detail:

The PDFs are opened from the Termux "directory" inside the Files app.
PDF Viewer version is 31 (latest).

Device / OS information:

Device: Pixel 8
OS: GrapheneOS 2025122500 (latest)
Optional security patches: enabled

de0u

DeletedUser592 When I open a PDF magazine with several hundred pages (but 80MB to 200MB of size), the viewer starts to lag after a few pages. More surprisingly, it appears to cause Molly to crash silently (no error message).

I noticed this because I use Molly with WebSockets instead of UnifiedPush. Each time Molly restarts, I receive a notification indicating that WebSockets is ready to receive messages again.

That is a great clue, but it is not a "crash". The Android system can stop apps for a variety of reasons, including if the system is running low on memory. Well-written apps are expected to save their state and to restart cleanly when directed to do so, so that the system's management of memory and battery life is transparent (the launcher keeps a screen image of the app handy from the time it is stopped until the time it is restarted).

It sounds as if opening a large PDF results in the system running low on memory. This may be more likely to happen if the PDF contains many images, as opposed to text.

DeletedUser592

de0u
I understand better, thank you!

However, I’m surprised that the system would run out of memory with a file that’s less than 200MB. Any idea why?

de0u

DeletedUser592 Sure! PDFs are heavily compressed, especially images. Displaying a heavily-compressed page requires a lot more memory than storing the compressed version.