Use animators for gestures and camera animations

[1ec5]

The Android SDK should use animators to drive camera transitions in response to gestures and calls to methods like animateTo(). We should move off mbgl::AnimationOptions and use the mbgl::Transform methods only for incremental transform changes on each frame of the animation.

A key benefit is that the Android SDK will be able to implement concurrent animations (#3625) without us having to design an API around tweening, spring solving, or the like.

@tobrun started doing this as part of #8031. Perhaps there’s also prior art in the Qt SDK, where we’ve always relied on Qt animation APIs instead of mbgl’s.

/cc @zugaldia @ivovandongen @bsudekum

[1ec5]

#9808 (comment) demonstrates an implementation of animator-driven camera animations. 😍

[tobrun]

#9808 (comment) demonstrates an implementation of animator-driven camera animations. 😍

WIP code for that in https://github.com/mapbox/mapbox-gl-native/tree/tvn-android-animations

[tobrun]

The base API for this has landed in #10001, though we still need to hook our gestures and other animations into it. Reopening.