draw.js

var fs = require('fs');
var Canvas = require('canvas');
var songs = JSON.parse(fs.readFileSync('songs.json'));

var w = 2880, h = 1800;
var c = new Canvas(w, h);
var ctx = c.getContext('2d');

var artists = {}, i = 0;
var key = 'name';
var classes = songs.map(function(song) {
    if (artists[song[key]]) {
        return artists[song[key]];
    } else {
        return artists[song[key]] = i++;
    }
});

var cl = classes.length;

function d3_hsl_rgb(h, s, l) {
  var m1,
      m2;

  /* Some simple corrections for h, s and l. */
  h = h % 360; if (h < 0) h += 360;
  s = s < 0 ? 0 : s > 1 ? 1 : s;
  l = l < 0 ? 0 : l > 1 ? 1 : l;

  /* From FvD 13.37, CSS Color Module Level 3 */
  m2 = l <= 0.5 ? l * (1 + s) : l + s - l * s;
  m1 = 2 * l - m2;

  function v(h) {
    if (h > 360) h -= 360;
    else if (h < 0) h += 360;
    if (h < 60) return m1 + (m2 - m1) * h / 60;
    if (h < 180) return m2;
    if (h < 240) return m1 + (m2 - m1) * (240 - h) / 60;
    return m1;
  }

  function vv(h) {
    return Math.round(v(h) * 255);
  }

  return [vv(h + 120), vv(h), vv(h - 120)];
}


var l = classes.length;
var rows = 100;
var perrow = l / rows;

var rowh = h / rows;

function x(c) {
    return (c / perrow) * w;
}

classes.forEach(function(c, i) {
    var rgb = d3_hsl_rgb(c, 0.5, 0.5);
    ctx.fillStyle = 'rgb(' + rgb + ')';
    var row = Math.floor(i / perrow);
    var rowcut = row * perrow;
    ctx.fillRect(x(i - rowcut), rowh * row, x((i - rowcut)+1), rowh * (1 + row));
});

fs.writeFileSync('names.png', c.toBuffer());