Function pointRing

explainshell/web/static/js/d3.v3.js:2405–2408

(λ, φ)

      var segments, visibleArea, invisibleArea, invisible;
      var buffer = d3_geo_clipBufferListener(), ringListener = clipLine(buffer), ring;
      function pointRing(λ, φ) {
        ringListener.point(λ, φ);
        ring.push([ λ, φ ]);
      }
      function ringStart() {
        ringListener.lineStart();
        ring = [];