Blur frozen on Android API 31

[jakobulbrich]

On Android 12 (API 31) the blur is frozen while scrolling. Only when the bottom navigation appears or disappears the blur quickly updates and is then frozen again.

Seems like HazeNode31.onObservedReadsChanged() is not called. Probably a bug in Compose or can we do something about it?

See attached video of the android-jetpack sample on API 31. It is working as expected on API 32.

https://github.com/chrisbanes/haze/assets/16408565/efc8f36b-0637-4e3f-b132-13311aca464b

[chrisbanes]

So it seems that the draw() function isn't being called consistently on API 31, but is on API 32+. I'll raise on the Compose Issue Tracker.

[chrisbanes]

https://issuetracker.google.com/issues/318679450

[chrisbanes]

I'll have another play tomorrow and see if I can get something working. If not I'll probably have to bump up the min SDK level for the blur impl to 32 for now.

[gleb-skobinsky]

I hope I can add some context as to the origins and the reason why this bug happens. It appears that everything is okay on the Compose side. The issue here is with the RenderNode. My hypothesis is that on API 31, it fails to refresh on the JNI side if its position has not updated since the latest draw call. More specifically, in this part of the code:

private fun Effect.updateRenderNodePosition() {
    renderNode.setPosition(0, 0, bounds.width.toInt(), bounds.height.toInt())
    renderNode.translationX = bounds.left
    renderNode.translationY = bounds.top
    renderNodeDirty = false
  }

If we feed different positions at each call, the RenderNode is updated successfully. It is not acceptable to use in the library, of course, but I wrote a little dirty hack to reproduce this behavour: https://github.com/gleb-skobinsky/haze/blob/main/haze/src/androidMain/kotlin/dev/chrisbanes/haze/AndroidHazeNode.kt

https://github.com/chrisbanes/haze/assets/90451272/7853ba32-dc82-471d-99f7-3ce7c6020a79

[gleb-skobinsky]

The video is so short because github does not accept long screen recordings :)

[gleb-skobinsky]

UPD: I managed to remove the freeze on SDK level 31 without the hacks! Just applied the translation to the setPosition method instead of translation in the record lambda. Check out the source code

[gleb-skobinsky]

It took hours to debug this...

[chrisbanes]

Great detective work @gleb-skobinsky! Send a PR over?

[gleb-skobinsky]

Yes, I will create a PR today

[chrisbanes]

Going to close this, as there's not much we can do. RenderNode received a number of improvements and fixes in Android SDK 32 which we rely on. Therefore we'll need to keep our current behaviour of not using the blur effect on SDK 31.

[Skaldebane]

Could this be an emulator-specific quirk? I do encounter this bug on an Android 12 emulator, but no physical device I tried thus far exerts this behavior.

I have a Samsung Galaxy A11 running Android 12, and it works fine there.

I also tried some Firebase Remote devices with SDK 31:

1. Samsung Galaxy A51: Haze works properly, content is updated properly.
2. Google Pixel 6a: Haze works properly. And this is the closest we can be to AOSP.

There's definitely better ways to get access to more devices, but I guess this paints a good general picture of what's going on. I suspect the emulated graphics in the emulator have something to do with it, but I may be wrong about that.

Though I'd love to see a Xiaomi being tested, since they're notorious for creating their own bugs (let alone fixing AOSP ones), and any other devices.

[chrisbanes]

Just like @Skaldebane, I just tried the Haze Samples on a Pixel 6 and Samsung A51 on SDK Level 31 and everything seems to be running fine. I don't have any other SDK 31 devices so this is as much testing as I can do.

I see two paths forward:

1. Enable blurring on SDK Level 31 (also known as the yolo plan).
2. Add a flag which allows devs to enableBlurringOnProblematicPlatforms, probably defaulting to false. When true, we enable the effect on SDK 31.

I'm leaning to option 2, but happy to hear suggestions.

Even if this only happens on the SDK 31 emulator, that's still something which devs are going to use.

[Skaldebane]

Option 2 seems like a safer bet, but would also mean that most developers won't ever opt into it (defaults always win). Not that big of deal given that it's already disabled in current versions, and developers will make sure to have good fallback anyways for older Android versions.

Though if option 1 is the path you end up choosing, it might be a good idea to have the flag, just set to true by default instead.

Of course the equation changes if an efficient blurring method for older versions is found (#140), but then we can use the "compat" version on Android 12 by default.

[chrisbanes]

Thinking about it, I think a blurEnabled: () -> Boolean block is the way to go.

It will default to calling a public function, but you can override it however you wish. This is platform-agnostic too, which is a big bonus.

[Skaldebane]

@chrisbanes That's a great idea!

I assume it's just going to ignore the value on SDK lower than 31 on Android, right?

[chrisbanes]

I assume it's just going to ignore the value on SDK lower than 31 on Android, right?

Yes, exactly. It will ignore values where blurring is not feasible.

[chrisbanes]

One the PR above lands, you'll be able to do the following and enable blurring everywhere (where it's technically possible):

Modifier.hazeChild(...) {
  blurEnabled = true
}