iTunes Top 100 Collage

server.js

var request = require('request')
  , sys = require('sys')
  , fs = require('fs')
  , mkdirp = require('mkdirp')
  , gm = require('gm').subClass({ imageMagick: true });

var n = 100;
var l = Math.sqrt(n);
var w = Math.sqrt(n);
var width = 170;
var height = 170;
var explicit = true;

var canvasHeight = n * 170;
var canvasWidth = n * 170;

var itunesURL = "https://itunes.apple.com/us/rss/toppodcasts/limit=" + n + "/explicit=" + explicit + "/json";

/*
request(itunesURL, function (error, response, body) {
	if (!error && response.statusCode == 200) {

		var result = JSON.parse(body);
		var entries = result.feed.entry;

		for (var i = 0; i < l; i++) {
			for (var k = 0; k < w; k++) {
				var pos = i * k;
				var entry = entries[pos];
				var imageURL = entry['im:image'][2].label;
				
				request(imageURL).pipe(fs.createWriteStream(__dirname + '/tmp/' + i * k + '.jpg'));
			}
		}
	}
});
*/

var output = gm();

fs.readdir(__dirname + '/tmp/', function(err, files){
    if (err) throw err;
    
    //http://stackoverflow.com/questions/6377362/calculating-or-rows-and-columns
    var num = files.length;
    if (num % 2 !== 0) num--;
    var rows = Math.floor(Math.sqrt(num));
	while(num % rows !== 0) {
	     rows--;
	}
	var columns = num / rows;
	var counter = 0;

    for (var i = 0; i < rows; i++) {
		for (var k = 0; k < columns; k++) {
			var file = files[counter];
			output.in('-page', '+' + i * 170 + '+' + k * 170);
			output.in('/tmp/' + file);
			counter++;
		}
	}

    output
      .mosaic()
      .write('output.jpg', function (err) {
        if (err) console.log(err);
      });
});