afterdrag event?

[mbostock]

As nice as it is to process the drag gestures independently, we might also need a hook for running code after all the active pointers have moved. Hopefully this will allow us to build a zoom gesture on top of the drag gesture…

[mbostock]

This’ll probably require unifying the separate move and end listeners for each pointer, and instead use reference tracking, like the zoom behavior does in D3 3.x. But that’s not so bad.

[mbostock]

I’d like to avoid this for now. I don’t think the zoom behavior will be built on top of the drag behavior. Typically the number of touches is tiny (1-2) so the cost of something like re-rendering twice during drag is negligible.