Align annotation rotation and pitch with map

[1ec5]

Annotations maintain their perspective even as you rotate and pitch the map. But sometimes you want an annotation to stay fixed, so that it rotates and tilts with the map. A contrived example would be an arrow that points in a particular direction – you’d want the direction to be in sync with the map’s direction.

/cc @incanus @ansis

[incanus]

Meaning symbols, not shapes. Another related issue here is raster ground overlays, as they're called in other frameworks, which work similarly to the not-yet-ported-here video source type — rectangles or other polygons of outside material stuck to the panning, zooming, rotating map.

[incanus]

Sorry, I do mean rasters here, not vector-drawn shapes in geo terms as a hack to stick things to the map.

Here is a good illustrative example from another toolkit:

[ansis]

This can be done internally by setting the "icon-rotation-alignment" style property to "map" instead of the default "viewport". I'm not sure how you want to expose the option though

[1ec5]

If it were just about point annotations, I’d say we could add a rotates property to MGLAnnotationImage. But we don’t have an equivalent interface for overlays, so we’ve been cramming methods into MGLMapViewDelegate for various sundry overlay properties. I’m hesitant to keep doing that.

[aksonov]

@1ec5 Could you check that commit nitaliano/react-native-mapbox-gl@bbb7040 ? It adds 'rotatedImage!' with rotation param.

[1ec5]

nitaliano/react-native-mapbox-gl#280 modifies an MGLAnnotationImage’s image to compensate for the map’s rotation. That approach breaks down as soon as the map is rotated, whether programmatically or due to a user gesture.

We don’t intend to support this feature for MGLAnnotationImage right now. Instead, we should implement a new property on MGLAnnotationView (#4801) that causes it to ignore the map’s rotation, similar to #5085 and #5067.

For non-view-backed point annotations, we’re waiting on #837 to enable full styling of arbitrary features on the map; once that works, it’ll be trivial to keep a point annotation from rotating using the approach outlined in #2528 (comment), no transforms needed.

[1ec5]

For non-view-backed point annotations, we’re waiting on #837 to enable full styling of arbitrary features on the map; once that works, it’ll be trivial to keep a point annotation from rotating using the approach outlined in #2528 (comment), no transforms needed.

As a workaround, you can now use the runtime styling API (MGLShapeSource and MGLSymbolStyleLayer) to implement something approximating a point annotation whose rotation matches the map. Use the MGLSymbolStyleLayer.iconRotationAlignment property to make the icon’s rotation match the map. #9479 implements an iconPitchAlignment property for matching the map’s pitch; it’ll be in the next release (tentatively versioned v3.7.0).

[stale]

This issue has been automatically detected as stale because it has not had recent activity and will be archived. Thank you for your contributions.

[julianrex]

/cc @fabian-guerra