[FEATURE] Replicate Markers in all world copies

[monsieurtanuki]

What do you want implemented?

Currently Markers are displayed only once (or not at all), even if the map displays several occurrences of the world.

A side-effect (called "teleportation") is that a Marker will appear in one occurrence of the world, then where the user scrolls a bit the Marker may "jump" into another occurrence of the world (typically the closest one to the screen center).
In the same spirit, close Markers may be displayed almost a world apart, because they were "affected" to a different world copy.

A solution would be to display all potentially visible Markers, which means duplicated Markers.

Same considerations apply to Polygons, Polylines and CircleMarkers.

cf. #1969 (comment)

What other alternatives are available?

No response

Can you provide any other information?

I started to code something interesting, with the following results.

Severity

Minimum: Not required for my use

[monsieurtanuki]

Done for Markers in #2000.

With a little bug though, evoked in #2000 (comment)

Separately, I've also noticed that onTap (and probably the rest of the handlers in MapOptions) callback in the Markers page in the example does not add the marker to the location tapped, if that location is not in the main world. It adds it to the closest point in the main world.

I've just tested again the "Markers" example, and could replicate the bug. For the record this example is blocked on a single world. I'd test a mix of the "Markers" example in multi-world, but flutter_map upgraded to the latest version of flutter, which isn't convenient for me at the moment.