CameraState.animateTo() completes without moving the camera

[maximeg]

What happened?

cameraState.animateTo(newPosition) returns normally, but cameraState.position never changes, map does not move. No exception, no crash, no log output. Reproduces identically on Android and iOS.

cameraState.jumpTo(boundingBox, ...) shows the same symptom (initial bounds fit never applies).

Direct assignment (cameraState.position = newPosition) works reliably as a workaround. Having duration = Duration.ZERO works also.

Affected Platforms

• Android
• iOS
• Desktop - macOS (JVM)
• Desktop - Linux (JVM)
• Desktop - Windows (JVM)
• Browser (JS)
• Browser (Wasm)

Platform Version

Android 14 (physical device), iOS 17+ (simulator/device)

Library Version

0.15.0

Sample Code

@Composable
fun MyMap() {
    val cameraState = rememberCameraState(firstPosition = CameraPosition(
        target = Position(longitude = 2.3522, latitude = 48.8566),
        zoom = 10.0,
    ))
    val scope = rememberCoroutineScope()

    Column {
        MaplibreMap(
            modifier = Modifier.fillMaxWidth().height(400.dp),
            cameraState = cameraState,
        )
        Button(onClick = {
            scope.launch {
                cameraState.animateTo(
                    CameraPosition(
                        target = Position(longitude = -0.1276, latitude = 51.5072),
                        zoom = 10.0,
                    )
                )
                // cameraState.position still equals the Paris position here.
            }
        }) {
            Text("Fly to London")
        }
    }
}

[sargunv]

do you have the same issue with flyTo?

[maximeg]

CameraState does not have flyTo if I'm correct. How do I try?

Note: animateTo(newPosition, duration = Duration.ZERO) works.

[sargunv]

ah sorry, I mixed it up with the demo app's flyTo

the demo app is calling animateTo without issue, and the pattern looks to be about the same, rememberCoroutineScope, scope.launch

[maximeg]

Yes, the issue is weird. It worked in < 0.15 and I was surprised it didn't work with nativefffi. I didn't see any obvious reason why it does not work.

[sargunv]

does it work on desktop? mlnffi landed on desktop in v0.14, then android/ios in v0.15

I'm not too surprised if some new bugs appear with mlnffi; it's essentially a ground up rewrite. But I'm unsure why the demo app doesn't repro it

[sargunv]

we also have MapCameraTransitionTest that should catch such a bug

[maximeg]

DEBUG duration-test: before, position=CameraPosition(bearing=-0.0, target=Position(longitude=1.6934196871220877, latitude=48.83547375650147, altitude=null), tilt=0.0, zoom=9.433348291948873)
DEBUG duration-test: after animateTo(2s), position=CameraPosition(bearing=-0.0, target=Position(longitude=1.6934196871284257, latitude=48.83547375650155, altitude=null), tilt=0.0, zoom=9.433348291948873)

There is a very slight movement, very very tiny...

[maximeg]

Oh you may have found the issue with 2f5ae8c

[sargunv]

There is a very slight movement, very very tiny...

That can happen if some other operation causes the animation to cancel. Could you share more of the reproducing project?

[maximeg]

I managed to isolate the issue :

I use maximumFps to reduce fps when map is idle (the numerous layers I have on the map don't need any animation, and are updated every 200ms or so).
Maybe you can tell me if nativeffi has some optimizations that could let me avoid doing this.

    // ...
    val idleFrameRate = if (cameraState.isCameraMoving) null else 10

    MaplibreMap(
        modifier    = modifier,
        baseStyle   = BaseStyle.Uri(POSITRON_STYLE_URL),
        cameraState = cameraState,
        zoomRange   = 4f..18f,
        options     = MapOptions(
            renderOptions   = renderOptionsWithMaximumFps(idleFrameRate),   // without this, animateTo works perfectly
        ) {}
     // ...


// Note that I had to do expect/actual because RenderOptions has different arguments between native ios & native android
// Don't know yet if this is the case still with nativeffi, I didn't have a look yet
fun renderOptionsWithMaximumFps(maximumFps: Int?): RenderOptions =
    RenderOptions(maximumFps = maximumFps)

[sargunv]

I use maximumFps to reduce fps when map is idle

that's unnecessary. The map idles on its own when nothing is changing; maximumFps is just that, a maximum.

[maximeg]

Thanks, I removed it for now.
I'll do some comparative studies on CPU usage at some point to see what can be done and if it is interesting (my users run on airplanes and the devices can become very very hot due to high sensors usage and the general heat / sun exposition, so any % of CPU gained is important)

[maximeg]

BTW, thanks for the huge work, nativeffi is a very big milestone for the project!

[sargunv]

Note that I had to do expect/actual because RenderOptions has different arguments between native ios & native android

in v0.15, RenderOptions has one actual on android/ios/desktop, and another on web.

[sargunv]

My triage agent managed to root cause this with your max fps repro. I haven't look deeply yet but it looks like:

• certain operations, especially those that set camera constraints, interrupt animations
• recompositions were unnecessarily making no-op changes to camera constraints
• the renderOptions change was triggering such a recomposition

will fix for next release.