Flickering pins on annotation updates

[mrylmz]

ClusterKit is causing a flickering issue on custom annotation views using MapKit.

I have tried solving this issue by using: - addAnnotations(...) and - removeAnnotations(...),
but that doesn't seam to solve the problem.

I'm calling - updateClustersIfNeeded in -mapView(_:, regionDidChangeAnimated:) as described in the documentation.

Tested with:

• iOS Version 11.0 GM Seed

[maxep]

Thanks for the report @roccx , I've also noticed that flickering on iOS11
I havent found a solution yet.

[jacogasp]

I'm using custom annotations views with an animation during the update and running iOS11.
Everything works perfectly but the animation occurs also for clusters/annotations that don't change during the update.
For me it seems like that during mapView(_:, regionDidChangeAnimated:) all the annotations are rebuilt even the ones that should not be updated. Could the flickering related to this?

[mrylmz]

I think the issue is that every annotation is replaced by new ones as @jacogasp says. Isn't there a way to filter annotations by -isEqual(_:) or -hash?

[lennartstein]

I did some debugging and I can say, that the flickering just happens when zooming not when moving the map to west/east/north/south. mapView(_:, regionDidChangeAnimated:) just rebuilt the annotations when zooming and moving the map. When moving without zooming it doesn't happen. Maybe there is some issue with the zooming?

[mrylmz]

It seems like MKMapView is delaying the rendering process of new annotations in some way. Yes I think the annotations are all rebuild because the algorithm instance is getting replaced on zoom.

I think a solution for that problem would be to manage the annotations in a more smarter way or just delay the removal of the old annotations by 2 or 3 frames.

[jacogasp]

@frgmt the refresh occurs to me also panning the map without zooming.

[maxep]

The issue appears everytime the clusters are updated, on zoom or significant pan. As @roccx suggested, adding an annotation to MKMapView seems to be delayed. The idea would be to update the clusters (replace, expand, collapse) more efficiely. The update is made in the private method updateMapRect:animated:, the implementation should be rethink.

[kkvinokk]

@maxep is anyone working on the solution for this issue? Please let us know when this is fixed.

In the time being is there any good alternative to fix this issue?

[thibauddavid]

I had the similar problem, and after some research, it happens that ClusterKit reloads each annotations on each pan, rotation etc.
I began to debug the lib, but didn't found any problem in the algorithm which could cause this bug.
As some said above, the underlying problem is that annotation adding are delayed in MKMapView compared to annotation removal (even if they are added before other get removed.)

In my case, the issue was mainly visible because I have several type of annotationViews, on which I update the image depending on type of annotation to display.
As annotationViews got reused, same pin could be reconfigured from a previous recycled pin (with a different image), causing a glitch on each reload.

My workaround consists in having 1 reuseIdentifier per annotation type (including CKCluster), thus configuring my annotationViews only after instantiating them.
As a result, my annotationViews are 100% stable, without any glitch.

Hope that helps !

[maxep]

I've released a new version : 0.3.0 including breaking changes answering this issue.
The clusters' updates and animations are now more efficient and as @thibauddavid described, making a good use of the reusable annotation view is a good practice.

Please check the CHANGELOG

[thibauddavid]

Just read new algorithm, seems much more efficient 🔥