Allow direct setting of MGLMapView.camera properties

[friedbunny]

If we can find a reasonably safe way, we should allow properties such as MGLMapView.camera.pitch and friends to be set directly, rather than via a round-about method.

This:

map.camera = MGLMapCamera(lookingAtCenter: startingCenter, altitude: altitude, heading: 0, pitch: 60)

... could become:

map.camera.pitch = 60

/cc @1ec5 @incanus

[1ec5]

Off the top of my head, we could have MGLMapCamera maintain a backpointer to the MGLMapView that created it, or MGLMapView could observe changes to that MGLMapCamera’s properties. With KVO, it would be tricky to remove the observers at the right time.

With either approach, we’d need to figure out what to do when the same MGLMapCamera instance is set on two different MGLMapView’s – say, if the two map views are to be kept in sync. The developer would then expect a change to the camera’s property to affect both map views at the same time.

A third approach would be to use NSNotificationCenter somehow.

[jmkiley]

It is currently a little confusing, since you can type mapView.camera.pitch = 40, for example, but it doesn't change the pitch.

Since it's readwrite, we may want to update documentation with how to actually set camera properties.

[1ec5]

we may want to update documentation with how to actually set camera properties.

I would agree if we intend to keep that behavior. But if we intend to make it possible to set the pitch directly like that, then I guess we’d consider the current behavior to be essentially a bug that isn’t to be documented.

[1ec5]

This will surely exacerbate #3625: developers will attempt to set the center coordinate, heading, and pitch directly on the map view on separate lines, but each successive property write will cancel the previous one.

Essentially, the current behavior makes MGLMapCamera a transactional API, which suits our (hobbled) animation model well.

[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.