1 d3.scale.quantize = function() {

     2   return d3_scale_quantize(0, 1, [0, 1]);

     3 };

     4 

     5 function d3_scale_quantize(x0, x1, range) {

     6   var kx, i;

     7 

     8   function scale(x) {

     9     return range[Math.max(0, Math.min(i, Math.floor(kx * (x - x0))))];

    10   }

    11 

    12   function rescale() {

    13     kx = range.length / (x1 - x0);

    14     i = range.length - 1;

    15     return scale;

    16   }

    17 

    18   scale.domain = function(x) {

    19     if (!arguments.length) return [x0, x1];

    20     x0 = +x[0];

    21     x1 = +x[x.length - 1];

    22     return rescale();

    23   };

    24 

    25   scale.range = function(x) {

    26     if (!arguments.length) return range;

    27     range = x;

    28     return rescale();

    29   };

    30 

    31   scale.copy = function() {

    32     return d3_scale_quantize(x0, x1, range); // copy on write

    33   };

    34 

    35   return rescale();

    36 };