1 function d3_scale_polylinear(domain, range, uninterpolate, interpolate) {

     2   var u = [],

     3       i = [],

     4       j = 0,

     5       n = domain.length;

     6 

     7   while (++j < n) {

     8     u.push(uninterpolate(domain[j - 1], domain[j]));

     9     i.push(interpolate(range[j - 1], range[j]));

    10   }

    11 

    12   return function(x) {

    13     var j = d3.bisect(domain, x, 1, domain.length - 1) - 1;

    14     return i[j](u[j](x));

    15   };

    16 }