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動画のスクリーンショットを撮るキーボードショートカットを追加する
// ==UserScript==
// @name YouTube: Take screenshots using hotkey
// @description 動画のスクリーンショットを撮るキーボードショートカットを追加する
// @namespace https://gitlab.com/sigsign
// @version 0.4.0
// @author Sigsign
// @license MIT or Apache-2.0
// @match https://www.youtube.com/*
// @grant none
// ==/UserScript==
(function () {
'use strict';
const MAX_CAPTURE_SIZE = 720;
const infoCache = {
url: '',
title: '',
icon: '',
expire: 0,
};
const notifications = new Set();
let permissionCache = Notification.permission;
async function convert(bitmap) {
const { width, height } = getSize(bitmap);
const canvas = document.createElement('canvas');
canvas.width = width;
canvas.height = height;
const ctx = canvas.getContext('2d');
if (!ctx) {
throw new Error('[Err] canvas.getContext() is failed');
}
ctx.imageSmoothingQuality = 'high';
ctx.drawImage(bitmap, 0, 0, bitmap.width, bitmap.height, 0, 0, width, height);
return await getBlob(canvas);
}
// [Firefox] dom.events.asyncClipboard.clipboardItem => True
async function copyToClipboard(blob) {
// eslint-disable-next-line no-undef
const clipboardItem = new ClipboardItem({
[blob.type]: blob
});
await navigator.clipboard.write([clipboardItem]);
}
function getBlob(canvas) {
return new Promise((resolv, reject) => {
canvas.toBlob((blob) => {
return (blob) ? resolv(blob) : reject('[Err] blob is null');
}, 'image/png');
});
}
function getIcon() {
const icon = document.querySelector('ytd-video-owner-renderer img');
return icon?.src || null;
}
function getInfo() {
if (infoCache.expire > Date.now() && infoCache.url === location.href) {
return { title: infoCache.title, icon: infoCache.icon };
}
const title = getTitle();
const icon = getIcon();
if (title && icon) {
infoCache.url = location.href;
infoCache.title = title;
infoCache.icon = icon;
infoCache.expire = Date.now() + (5 * 60 * 1000); // 5 minutes
}
return { title: title || '', icon: icon || '' };
}
function getSize(bitmap) {
let width = bitmap.width;
let height = bitmap.height;
// 短辺を MAX_CAPTURE_SIZE 以下にする
if (width > height) {
if (height > MAX_CAPTURE_SIZE) {
width = width * MAX_CAPTURE_SIZE / height;
height = MAX_CAPTURE_SIZE;
}
}
else {
if (width > MAX_CAPTURE_SIZE) {
height = height * MAX_CAPTURE_SIZE / width;
width = MAX_CAPTURE_SIZE;
}
}
return { width, height };
}
function getTitle() {
const title = location.pathname.startsWith('/embed/')
? document.querySelector('#movie_player .ytp-title-text')
: document.querySelector('ytd-video-primary-info-renderer h1.title');
return title?.textContent?.trim() || null;
}
async function notify(blob) {
if (permissionCache === 'denied') {
return;
}
if (permissionCache !== 'granted') {
permissionCache = await Notification.requestPermission();
if (permissionCache !== 'granted') {
return;
}
}
// 連続して撮るときは過去の通知を消す
for (const n of notifications) {
n.close();
}
notifications.clear();
const { title, icon } = getInfo();
const url = URL.createObjectURL(blob);
const options = {
body: title,
icon: icon,
image: url,
silent: true,
};
const notify = new Notification('Take a screenshot', options);
notify.addEventListener('click', (ev) => {
ev.preventDefault();
const url = URL.createObjectURL(blob);
setTimeout(function (u) {
URL.revokeObjectURL(u);
}, 5 * 60 * 1000, url);
window.open(url, '_blank');
}, false);
setTimeout(function (n, u) {
n.close();
URL.revokeObjectURL(u);
notifications.delete(n);
}, 5 * 1000, notify, url);
notifications.add(notify);
}
async function takeScreenshot() {
const player = document.querySelector('#movie_player');
if (!player) {
throw new Error('[Err] YouTube Player is not ready');
}
const video = player.querySelector('video');
if (!video) {
throw new Error('[Err] HTMLVideoElement is not exists');
}
const list = player.classList;
if (!list.contains('playing-mode') && !list.contains('paused-mode')) {
return;
}
if (list.contains('unstarted-mode')) {
return;
}
const bitmap = await createImageBitmap(video);
const blob = await convert(bitmap);
await copyToClipboard(blob);
await notify(blob);
}
function init() {
const path = location.pathname;
// チャット欄にフォーカスがあってもスクショを撮れるようにする
if (path.includes('/live_chat') || path.includes('/live_chat_replay')) {
window.addEventListener('keydown', function (ev) {
if (ev.key.toLowerCase() !== 'q' || ev.target !== document.body) {
return;
}
const message = {
type: 'userscript-take-screenshots'
};
window.parent.postMessage(message);
}, false);
// チャット欄でやることはもうない
return;
}
// 最上位のフレームだけが postMessage() を受け取る
if (window.top === window.self) {
window.addEventListener('message', (ev) => {
const url = new URL(ev.origin);
if (url.hostname !== 'www.youtube.com' || !ev.data) {
return;
}
const message = ev.data;
if (message.type === 'userscript-take-screenshots') {
takeScreenshot().catch((err) => {
console.error(err);
});
}
}, false);
}
window.addEventListener('keydown', (ev) => {
if (ev.key.toLowerCase() !== 'q') {
return;
}
const target = ev.target;
if (target instanceof HTMLInputElement || target instanceof HTMLTextAreaElement) {
return;
}
takeScreenshot().catch((err) => {
console.error(err);
});
}, false);
}
init();
})();