Function piecewise

external/.d3.js:4015–4023

(interpolate, values)

var cubehelixLong = cubehelix$1(nogamma);

function piecewise(interpolate, values) {
  if (values === undefined) values = interpolate, interpolate = interpolate$2;
  var i = 0, n = values.length - 1, v = values[0], I = new Array(n < 0 ? 0 : n);
  while (i < n) I[i] = interpolate(v, v = values[++i]);
  return function(t) {
    var i = Math.max(0, Math.min(n - 1, Math.floor(t *= n)));
    return I[i](t - i);
  };
}

function quantize$1(interpolator, n) {
  var samples = new Array(n);