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YouTube Bolder Subtitles

YouTubeの字幕を太字にして見やすくします。

このスクリプトの質問や評価の投稿はこちら通報はこちらへお寄せください。
// ==UserScript==
// @name        YouTube Bolder Subtitles
// @name:ja     YouTube Bolder Subtitles
// @name:zh-CN  YouTube Bolder Subtitles
// @namespace   knoa.jp
// @description Make subtitles bolder for better visibility on YouTube.
// @description:ja YouTubeの字幕を太字にして見やすくします。
// @description:zh-CN 将YouTube上的字幕放成粗体字,让人更容易看清。
// @include     https://www.youtube.com/*
// @include     https://www.youtube-nocookie.com/embed/*
// @exclude     https://www.youtube.com/live_chat*
// @exclude     https://www.youtube.com/live_chat_replay*
// @version     1.1.0
// @grant       none
// ==/UserScript==

(function(){
  const SCRIPTID = 'YouTubeBolderSubtitles';
  const SCRIPTNAME = 'YouTube Bolder Subtitles';
  const DEBUG = false;/*
[update]
Also available on embedded videos on youtube-nocookie.com. Internal code preparation.

[bug]

[todo]
デフォルトのオプションをクリックできないようにしとくか
元々の太字には文字の大きさとかで対処する?
もうちょっと込み入った背景のスクショで見やすさを強調したい

[possible]
設定パネルでカスタマイズ?
  YouTubeの設定パネルに選択肢を差し込む?

[research]
normalizeが必要なのはABCやNBCなどのテレビ局が独自に挿入する字幕システムのせいっぽい? (Bob the Canadian のライブに付く自動字幕は問題なかった)
  と思ったら、動画でもあったはず。URL失念。

[memo]
  */
  if(window === top && console.time) console.time(SCRIPTID);
  const MS = 1, SECOND = 1000*MS, MINUTE = 60*SECOND, HOUR = 60*MINUTE, DAY = 24*HOUR, WEEK = 7*DAY, MONTH = 30*DAY, YEAR = 365*DAY;
  const site = {
    targets: {
      title: () => $('title'),
    },
    get: {
      moviePlayer: () => $('#movie_player'),
      captionWindow: (player) => player.querySelector('.caption-window'),
    },
  };
  let elements = {}, flags = {}, timers = {}, sizes = {}, panels, configs;
  const core = {
    initialize: function(){
      elements.html = document.documentElement;
      elements.html.classList.add(SCRIPTID);
      //core.observeTitle();
      //core.observeCaption();
      core.addStyle('style');
    },
    observeTitle: function(){
      observe(elements.title, function(records){
        log('Title has changed:', elements.title.textContent);
      }, {childList: true, subtree: true, characterData: true});
    },
    observeCaption: function(){
      // 100msくらいにスロットルする?
      // 時刻が変わっても検知してしまうのでは・・・
      //   observeを二重構造にしてcaptionを発見するごとにcaptionを監視する?
      const player = site.get.moviePlayer();
      observe(player, function(records){
        const caption = site.get.captionWindow(player);
        if(caption) caption.normalize();
      }, {childList: true, subtree: true, characterData: true});
    },
    addStyle: function(name = 'style', d = document){
      if(html[name] === undefined) return;
      if(!d.head) return d.addEventListener('load', (e) => core.addStyle(name, d), {once: true});
      let style = createElement(html[name]()), id = SCRIPTID + '-' + name;
      style.id = id;
      Array.from(d.styleSheets).forEach(s => s.ownerNode.id === id && d.head.removeChild(s.ownerNode));
      d.head.appendChild(style);
    },
  };
  const html = {
    style: () => `
      <style type="text/css">
        .caption-window{
          background: transparent !important;
          overflow: visible !important;
        }
        .ytp-caption-segment{
          text-shadow:
            rgb(0,0,0) 0 0 .1em,
            rgb(0,0,0) 0 0 .2em,
            rgb(0,0,0) 0 0 .4em,
            rgb(0,0,0) 0 0 .8em,
            transparent 0 0 0
          !important;
          background: transparent !important;
          font-weight: bold !important;
        }
      </style>
    `,
  };
  const setTimeout = window.setTimeout.bind(window), clearTimeout = window.clearTimeout.bind(window), setInterval = window.setInterval.bind(window), clearInterval = window.clearInterval.bind(window), requestAnimationFrame = window.requestAnimationFrame.bind(window), requestIdleCallback = window.requestIdleCallback.bind(window);
  const alert = window.alert.bind(window), confirm = window.confirm.bind(window), prompt = window.prompt.bind(window), getComputedStyle = window.getComputedStyle.bind(window), fetch = window.fetch.bind(window);
  if(!('isConnected' in Node.prototype)) Object.defineProperty(Node.prototype, 'isConnected', {get: function(){return document.contains(this)}});
  const $ = function(s, f = undefined){
    let target = document.querySelector(s);
    if(target === null) return null;
    return f ? f(target) : target;
  };
  const $$ = function(s, f = undefined){
    let targets = document.querySelectorAll(s);
    return f ? f(targets) : targets;
  };
  const createElement = function(html = '<div></div>'){
    let outer = document.createElement('div');
    outer.insertAdjacentHTML('afterbegin', html);
    return outer.firstElementChild;
  };
  const observe = function(element, callback, options = {childList: true, subtree: false, characterData: false, attributes: false, attributeFilter: undefined}){
    let observer = new MutationObserver(callback.bind(element));
    observer.observe(element, options);
    return observer;
  };
  const log = function(){
    if(typeof DEBUG === 'undefined') return;
    let l = log.last = log.now || new Date(), n = log.now = new Date();
    let error = new Error(), line = log.format.getLine(error), callers = log.format.getCallers(error);
    //console.log(error.stack);
    console.log(
      SCRIPTID + ':',
      /* 00:00:00.000  */ n.toLocaleTimeString() + '.' + n.getTime().toString().slice(-3),
      /* +0.000s       */ '+' + ((n-l)/1000).toFixed(3) + 's',
      /* :00           */ ':' + line,
      /* caller.caller */ (callers[2] ? callers[2] + '() => ' : '') +
      /* caller        */ (callers[1] || '') + '()',
      ...arguments
    );
  };
  log.formats = [{
      name: 'Firefox Scratchpad',
      detector: /MARKER@Scratchpad/,
      getLine: (e) => e.stack.split('\n')[1].match(/([0-9]+):[0-9]+$/)[1],
      getCallers: (e) => e.stack.match(/^[^@]*(?=@)/gm),
    }, {
      name: 'Firefox Console',
      detector: /MARKER@debugger/,
      getLine: (e) => e.stack.split('\n')[1].match(/([0-9]+):[0-9]+$/)[1],
      getCallers: (e) => e.stack.match(/^[^@]*(?=@)/gm),
    }, {
      name: 'Firefox Greasemonkey 3',
      detector: /\/gm_scripts\//,
      getLine: (e) => e.stack.split('\n')[1].match(/([0-9]+):[0-9]+$/)[1],
      getCallers: (e) => e.stack.match(/^[^@]*(?=@)/gm),
    }, {
      name: 'Firefox Greasemonkey 4+',
      detector: /MARKER@user-script:/,
      getLine: (e) => e.stack.split('\n')[1].match(/([0-9]+):[0-9]+$/)[1] - 500,
      getCallers: (e) => e.stack.match(/^[^@]*(?=@)/gm),
    }, {
      name: 'Firefox Tampermonkey',
      detector: /MARKER@moz-extension:/,
      getLine: (e) => e.stack.split('\n')[1].match(/([0-9]+):[0-9]+$/)[1] - 2,
      getCallers: (e) => e.stack.match(/^[^@]*(?=@)/gm),
    }, {
      name: 'Chrome Console',
      detector: /at MARKER \(<anonymous>/,
      getLine: (e) => e.stack.split('\n')[2].match(/([0-9]+):[0-9]+\)?$/)[1],
      getCallers: (e) => e.stack.match(/[^ ]+(?= \(<anonymous>)/gm),
    }, {
      name: 'Chrome Tampermonkey',
      detector: /at MARKER \(chrome-extension:.*?\/userscript.html\?name=/,
      getLine: (e) => e.stack.split('\n')[2].match(/([0-9]+):[0-9]+\)?$/)[1] - 1,
      getCallers: (e) => e.stack.match(/[^ ]+(?= \(chrome-extension:)/gm),
    }, {
      name: 'Chrome Extension',
      detector: /at MARKER \(chrome-extension:/,
      getLine: (e) => e.stack.split('\n')[2].match(/([0-9]+):[0-9]+\)?$/)[1],
      getCallers: (e) => e.stack.match(/[^ ]+(?= \(chrome-extension:)/gm),
    }, {
      name: 'Edge Console',
      detector: /at MARKER \(eval/,
      getLine: (e) => e.stack.split('\n')[2].match(/([0-9]+):[0-9]+\)$/)[1],
      getCallers: (e) => e.stack.match(/[^ ]+(?= \(eval)/gm),
    }, {
      name: 'Edge Tampermonkey',
      detector: /at MARKER \(Function/,
      getLine: (e) => e.stack.split('\n')[2].match(/([0-9]+):[0-9]+\)$/)[1] - 4,
      getCallers: (e) => e.stack.match(/[^ ]+(?= \(Function)/gm),
    }, {
      name: 'Safari',
      detector: /^MARKER$/m,
      getLine: (e) => 0,/*e.lineが用意されているが最終呼び出し位置のみ*/
      getCallers: (e) => e.stack.split('\n'),
    }, {
      name: 'Default',
      detector: /./,
      getLine: (e) => 0,
      getCallers: (e) => [],
  }];
  log.format = log.formats.find(function MARKER(f){
    if(!f.detector.test(new Error().stack)) return false;
    //console.log('////', f.name, 'wants', 0/*line*/, '\n' + new Error().stack);
    return true;
  });
  core.initialize();
  if(window === top && console.timeEnd) console.timeEnd(SCRIPTID);
})();