Unbounded horizontal scroll does not play well with longitude constraints near 180 or -180

[mbenoukaiss]

What is the bug?

Let's say someone wants to have a map constrained to Te Waipounamu, the south island of New Zealand, because why not. Good camera constraints coordinates would be between -38.82;164.37 and -49.49;177.86.

However because the bottom right corner is so close to longitude 180 and because of the way unbounded horizontal scroll is implemented, if you pan with enough speed towards the east, it will reach the constraints and jump you back to the west instead of stopping at the constraint.

I discovered it while trying to understand what causes #2071 precisely

How can we reproduce it?

Create a FlutterMap with the following property set in MapOptions : cameraConstraint: CameraConstraint.contain(bounds: LatLngBounds(const LatLng(-38.82, 164.37), const LatLng(-49.49, 177.86)))

Do you have a potential solution?

No idea yet, don't know how unbounded constraints work

[JaffaKetchup]

Hi @mbenoukaiss, thanks for all the research!

I'm aware that this could be an issue. Can you also just share your initial camera config? For me, the entire map just turns black if the initial camera is outside of the constraints.

[mbenoukaiss]

Can you also just share your initial camera config? For me, the entire map just turns black if the initial camera is outside of the constraints.

Hi, sorry for the insufficiently detailed snippet, by running the example app on the home route and with the following FlutterMap I manage to reproduce on ios and chrome (got to fling it hard though, harder than on mobile) :

FlutterMap(
  options: MapOptions(
    minZoom: 0,
    initialZoom: 8,
    maxZoom: 17,
    initialCenter: const LatLng(-44.28, 170.54),
    cameraConstraint: CameraConstraint.contain(
      bounds: LatLngBounds(
        const LatLng(-38.82, 164.37),
        const LatLng(-49.49, 177.86),
      ),
    ),
  ),
  children: [
    openStreetMapTileLayer,
    RichAttributionWidget(
      popupInitialDisplayDuration: const Duration(seconds: 5),
      animationConfig: const ScaleRAWA(),
      showFlutterMapAttribution: false,
      attributions: [
        TextSourceAttribution(
          'OpenStreetMap contributors',
          onTap: () async => launchUrl(
            Uri.parse('https://openstreetmap.org/copyright'),
          ),
        ),
        const TextSourceAttribution(
          'This attribution is the same throughout this app, except '
          'where otherwise specified',
          prependCopyright: false,
        ),
      ],
    ),
  ],
),