[New Study Screen] slower on GrapheneOS

[Chepycou]

Checked for duplicates?

• This issue is not a duplicate

Does it also happen in the desktop version?

• This bug does not occur in the latest version of Anki Desktop

What are the steps to reproduce this bug?

On Graphene OS (latest stable release), I can reproduce the bug even with the following settings

• App battery usage unrestricted (just in case it interfered)
• Exploit protection compatibility mode, which disables a lot of protections

Enable the new study screen and review some cards (the same happens both on custom cards of mine and on the simplest basic card type by default in Anki). The new study screen induces a .5s delay every time I answer and everytime I reveal the back.

Expected behaviour

I would expect the new screen to have similar or better delays than the older one

Debug info

AnkiDroid Version = 2.23.2 (250313087304b98facfc4219c4db10311e91ea69)  
Backend Version = 0.1.62-anki25.09.2 (25.09.2 3890e12c9e48c028c3f12aa58cb64bd9f8895e30)  
Android Version = 16 (SDK 36)  
ProductFlavor = play  
Device Info = Google | google | husky | husky | Pixel 8 Pro | husky  
Webview User Agent = Mozilla/5.0 (Linux; Android 16; Pixel 8 Pro Build/BP4A.251205.006.E1; wv) AppleWebKit/537.36 (KHTML, like Gecko) Version/4.0 Chrome/143.0.7499.146 Mobile Safari/537.36  
ACRA UUID = dd3f4b28-e16d-42a4-967a-d54369af538c  
FSRS = 5.1.0 (Enabled: true)  
Crash Reports Enabled = true

(Optional) Anything else you want to share?

Here is a deck with some cards on which I can confirm that the issue happens

Research

• I have checked the manual and the FAQ and could not find a solution to my issue
• (Optional) I have confirmed the issue is not resolved in the latest alpha release (instructions)

[BrayanDSO]

I believe that none of the current AnkiDroid contributors has a device running GrapheneOS, so we can't tell what's going on. It works fine on common devices.

My main hypothesis is that it doesn't allow caching files, and mathjax is being reloaded every time.

An alternative hypothesis is that it does some extra work when an JavaScript eval is sent.

Either way, only a dev with a GrapheneOS device would be able to help.

[Chepycou]

My main hypothesis is that it doesn't allow caching files, and mathjax is being reloaded every time

Would mathjax have an impact in basic cards with only text (no LaTeX being involved) ?

Either way, only a dev with a GrapheneOS device would be able to help.

Is there any way I can get a precise timing of what step takes how much time ? So that at least I can lead you on the right path.

[BrayanDSO]

Would mathjax have an impact in basic cards with only text (no LaTeX being involved) ?

yes. As Anki desktop does (we reuse the same code), MathJax is loaded when the study screen is opened.

Is there any way I can get a precise timing of what step takes how much time ?

1. You can plug in your device to a computer
   2; Then enable HTML debugging in the developer options (Press the AnkiDroid logo 6 times in the About page to enable developer options)
2. Enablin USB debugging in the device may be necessary
3. In your browser go to chrome:inspect
4. Wait until the device appears and start inspecting it
5. In the inspecting page, open the Network tab
6. Go flipping some cards and see if something is taking too long to load in the Network tab

[Chepycou]

All I get with USB debugging enabled is this :

[BrayanDSO]

With the study screen opened, does a inspect clickable text appear under Pixel 8 Pro? Like below

[Chepycou]

Never mind, it just took a long time to show up. Then immediately crashed 😂
Edit : it takes a lot of trials to get the "accept" pairing to appear on the phone, not sure what that is due to.

[Chepycou]

Finally got it to work Here is what I get :

[Chepycou]

Note that a favicon loads each time there is either a flipping of the card or an answer.

[Chepycou]

I can also see some warnings in the console tab, not sure if that's related :

[Chepycou]

I also tried switching to the older study screen and could see all the requests being done :