Fix zoom animation with Google Maps API v3.32

This is a new issue to discuss a long-term solution to the zoom animation problem that started with v3.32 of the Google Maps API. See also #490 #510 #530

I’ve begun work in https://github.com/stephenfarrar/google-map-react/tree/zoom-animation Someone could start a branch here, and I’ll create a pull request.

So far, here are some of the issues I’m confused about:

• The markers are children of overlay.div in src/google_map.js . That div used to be positioned & sized so that it was the size of the map. I don’t think that’s necessary, and I’ve removed it, but perhaps it’s causing problems elsewhere.

• I’m not totally sure what coordinate system is used in the geo service project() and unproject() when projectFromLeftTop is false. Did it mean ‘relative to the map center’? I’ve made it mean ‘relative to the MapPanes’. This makes sense for markers, but I’m not sure that it makes sense elsewhere.

• My branch has problems with markers disappearing and reappearing. Perhaps this indicates some problems with keeping track of the current map bounds.

[nickpolet]

Works beautifully. Nice job @stephenfarrar + @itsmichaeldiego.

[stephenfarrar]

@itsmichaeldiego No worries, I’ve also been on vacation the last week! Thanks for reviewing and leaving comments. I’ve tried to address them all, but let me know if things are still unclear.