Function point

d3-3.2.8/d3.js:1197–1199

(l)

      return [ (p[0] - translate[0]) / scale, (p[1] - translate[1]) / scale ];
    }
    function point(l) {
      return [ l[0] * scale + translate[0], l[1] * scale + translate[1] ];
    }
    function scaleTo(s) {
      scale = Math.max(scaleExtent[0], Math.min(scaleExtent[1], s));
    }