PixivのUgoiraをGIFにするブックマークレット的なやつ

ugoira.js

// あとでリファクタリングする
var b = "https://raw.githubusercontent.com/antimatter15/jsgif/master/";
var u = [
  "LZWEncoder.js", "NeuQuant.js", "GIFEncoder.js", "Demos/b64.js"
];
$("canvas").remove();
var $c = $("<canvas>").appendTo("body");
var ctx = $c[0].getContext("2d");

var d = document;
var i = 0;
u.forEach(function(r){
  var s = d.createElement("script");
  s.src = b + r;
  s.onload = function(){
    if(++i == u.length){
      load();
    }
  };
  d.body.appendChild(s);
});

function load(){
  var e = new GIFEncoder();
  e.setRepeat(0);
  e.setDelay(20);
  e.start();
  var d = pixiv.context.ugokuIllustData;
  var w = d.size[0] / 2;
  var h = d.size[1] / 2;
  $c.attr({
    width: w,
    height: h
  });
  var z = new ZipImagePlayer({
    canvas: $c[0],
    source: d.src,
    metadata: d,
    chunkSize: 3e5,
    loop: 1,
    autoStart: false
  });

  $(z).on("loadingStateChanged", function(a, c){
    if(c === 2){
      var imgs = z._frameImages;

      (function f(i){
        if(i == imgs.length){
          var bin = e.stream().getData();
          var url = 'data:image/gif;base64,'+encode64(bin);
          console.log(url);
          return;
        }
        var img = imgs[i];
        ctx.drawImage(img, 0, 0, w, h);
        e.addFrame(ctx);
        return f(++i);
      })(0);

    }
  });

}