mbostock/d3 — pull request #1132 by bm-w (2013-03-10 13:33:17+00:00)
Title: Implemented d3.svg.arc.cornerRadius 

See #1131. This implementation uses approach C for the case of large corner radius relative to arc length—i.e. using Bézier curve approximations to both align the corner start points with those of neighbouring slices and also touch the inner and outer radius, at the expense of the corners no longer being circular.