Add MGLCircle (with radius expressed in physical units)

[incanus]

Now that v8 has landed in 0451aca we have a Circle layer type.

[1ec5]

ref #1740

[cowgp]

@incanus is there a roadmap plan for when MGLCircle will be implemented? Trying to update from the old "RMMapView" based SDK and the lack of replacement for an RMCircle is blocking me.

[incanus]

Thanks for the ping on this @cowgp. It hasn't been on the roadmap, but thinking this was relatively straightforward, I took a look today in 2167-MGLCircle.

The Cocoa side was pretty easy, but as it turns out, even though we have support for circles in the renderer and styles as of 0451aca, we don't have support for circle annotations in that API.

It's an interesting bind, since circles seems like shapes (have alpha & color) but behave like points (have a single coordinate and a scalar icon-like property radius). So the going has been a little more than I expected there, but I think I'm close.

Stay tuned — will try to push this through soon.

/cc @friedbunny @jfirebaugh

[incanus]

@cowgp Sorry, I'm gonna have to say we're going to push this out a ways right now — too many higher priorities. If it was as easy as I had initially guessed, with pure Cocoa API, it would have been easy to rationalize, but increasing the surface area of our annotations API right now is not ideal given the other things we're integrating them with.

Stay tuned; I'd love to get this in, but it's not a priority roadmap right now.

[cowgp]

@incanus - Thanks so much for looking into it, I appreciate the effort. I do hope it can remain a priority, seems like an important feature from my perspective. That said, totally understand that this update is all new underpinnings and thus there's a lot to build up.

[incanus]

@cowgp Depending on if your needs are truly at runtime, you could possibly use the existing support in the style spec for rendering circles in the meantime? mapbox/mapbox-gl-js#1446 shows an example of how this looks in the style. You could also consider mutating the style JSON and custom setting it at runtime as a workaround.