Youtube 封面

获取视频封面!

您需要先安装一个扩展,例如 篡改猴Greasemonkey暴力猴,之后才能安装此脚本。

You will need to install an extension such as Tampermonkey to install this script.

您需要先安装一个扩展,例如 篡改猴暴力猴,之后才能安装此脚本。

您需要先安装一个扩展,例如 篡改猴Userscripts ,之后才能安装此脚本。

您需要先安装一款用户脚本管理器扩展,例如 Tampermonkey,才能安装此脚本。

您需要先安装用户脚本管理器扩展后才能安装此脚本。

(我已经安装了用户脚本管理器,让我安装!)

您需要先安装一款用户样式管理器扩展,比如 Stylus,才能安装此样式。

您需要先安装一款用户样式管理器扩展,比如 Stylus,才能安装此样式。

您需要先安装一款用户样式管理器扩展,比如 Stylus,才能安装此样式。

您需要先安装一款用户样式管理器扩展后才能安装此样式。

您需要先安装一款用户样式管理器扩展后才能安装此样式。

您需要先安装一款用户样式管理器扩展后才能安装此样式。

(我已经安装了用户样式管理器,让我安装!)

// ==UserScript==
// @name               Youtube 封面
// @name:en            Youtube Cover
// @name:zh-CN         Youtube 封面
// @namespace          http://tampermonkey.net/
// @version            1.4.7
// @description        獲取影片封面!
// @description:en     Get the cover of youtube video!
// @description:zh-CN  获取视频封面!
// @author             Anong0u0
// @match              *://*.youtube.com/*
// @icon               https://www.google.com/s2/favicons?sz=64&domain=youtube.com
// @grant              GM_setValue
// @grant              GM_getValue
// @grant              GM_registerMenuCommand
// @noframes
// @license            MIT License
// ==/UserScript==


const delay = (ms = 0) => new Promise((r)=>{setTimeout(r, ms)})

const waitElementLoad = (elementSelector, selectCount = 1, tryTimes = 1, interval = 0) =>
{
    return new Promise(async (resolve, reject)=>
    {
        let t = 1, result;
        while(true)
        {
            if(selectCount != 1) {if((result = document.querySelectorAll(elementSelector)).length >= selectCount) break;}
            else {if(result = document.querySelector(elementSelector)) break;}

            if(tryTimes>0 && ++t>tryTimes) return reject(new Error("Wait Timeout"));
            await delay(interval);
        }
        resolve(result);
    })
}

if (window.trustedTypes)
{
    const policy = trustedTypes.createPolicy("ytCover", {createHTML: (string) => string,});
    Node.prototype.setHTML = function (html) {this.innerHTML = policy.createHTML(html)}
}
else Node.prototype.setHTML = function (html) {this.innerHTML = html}

Node.prototype.getXY = function ()
{
    let x = 0, y = 0, element = this;
    while (element)
    {
        x += element.offsetLeft - element.scrollLeft + element.clientLeft;
        y += element.offsetTop - element.scrollLeft + element.clientTop;
        element = element.offsetParent;
    }
    return {X: x, Y: y}
}

const checkImg = async (url) => await fetch(url, { method: "HEAD" })
                                    .then(response => response.ok)
                                    .catch(() => false)


const main = () =>
{
    const div = document.createElement("div");
    div.style.marginLeft = "3em";
    div.setHTML(`

    <!-- css -->
    <style>
        #masthead-container { z-index: 3000 !important; }

        #ytCover {
            text-decoration: none;
            font-size: 2em;
            font-weight: bold;
            font-family: Roboto, Arial, sans-serif;
            color: var(--yt-spec-text-primary);
        }

        .list {
            background-color: var(--yt-spec-brand-background-primary);
            border: 1px solid var(--yt-spec-10-percent-layer);
            padding: 0.5em 0;
            position: fixed;
            z-index: 114514;
            max-height: 40em;
            font-size: 10px
        }

        .linkBtn {
            text-decoration: none;
        }

        .list-item {
            text-align: center;
            font-size: 1.5em;
            color: var(--yt-spec-text-primary);
            background-color: var(--yt-spec-brand-background-primary);
            height: 2.5em;
            line-height: 2.5em;
        }
        .list-item:hover {
            background: #AAA;
            box-shadow: 0 4px 5px rgba(0, 0, 0, 0.2);
        }

        .slide {
            cursor: default
        }

        img#preview {
            position: fixed;
            top: 50%;
            left: 50%;
            transform: translate(-50%, -50%);
            z-index: 2999;
            max-width: 100vw;
            max-height: 65vh;
            min-width: 40vw;
            border: 3px solid #FFF;
        }

        .list > button {
            border: none;
            padding: unset;
            width: inherit;
            cursor: pointer;
        }

    </style>

    <!-- html -->
    <div>
        <div class="slide" id="ytCover"></div>

        <div class="list" id="ytListHead" style="border-top: none; top: 4.8em; left: 19em;" hidden>

            <div class="list-item slide">1280x720+
                <div class="list" style="border-left: none; width: 11.5em" hidden>
                    <a class="linkBtn" imgTag="maxresdefault"><div class="list-item">maxresdefault</div></a>
                    <a class="linkBtn" imgTag="maxres1"><div class="list-item">maxres1</div></a>
                    <a class="linkBtn" imgTag="maxres2"><div class="list-item">maxres2</div></a>
                    <a class="linkBtn" imgTag="maxres3"><div class="list-item">maxres3</div></a>
                </div>
            </div>

            <div class="list-item slide">640x480
                <div class="list" style="border-left: none; width: 8.5em" hidden>
                    <a class="linkBtn" imgTag="sddefault"><div class="list-item">sddefault</div></a>
                    <a class="linkBtn" imgTag="sd1"><div class="list-item">sd1</div></a>
                    <a class="linkBtn" imgTag="sd2"><div class="list-item">sd2</div></a>
                    <a class="linkBtn" imgTag="sd3"><div class="list-item">sd3</div></a>
                </div>
            </div>

            <div class="list-item slide">480x360
                <div class="list" style="border-left: none; width: 8.5em" hidden>
                    <a class="linkBtn" imgTag="hqdefault"><div class="list-item">hqdefault</div></a>
                    <a class="linkBtn" imgTag="hq1"><div class="list-item">hq1</div></a>
                    <a class="linkBtn" imgTag="hq2"><div class="list-item">hq2</div></a>
                    <a class="linkBtn" imgTag="hq3"><div class="list-item">hq3</div></a>
                </div>
            </div>

            <div class="list-item slide">320x180
                <div class="list" style="border-left: none; width: 8.5em" hidden>
                    <a class="linkBtn" imgTag="mqdefault"><div class="list-item">mqdefault</div></a>
                    <a class="linkBtn" imgTag="mq1"><div class="list-item">mq1</div></a>
                    <a class="linkBtn" imgTag="mq2"><div class="list-item">mq2</div></a>
                    <a class="linkBtn" imgTag="mq3"><div class="list-item">mq3</div></a>
                </div>
            </div>

            <div class="list-item slide">120x90
                <div class="list" style="border-left: none; width: 6.5em" hidden>
                    <a class="linkBtn" imgTag="default"><div class="list-item">default</div></a>
                    <a class="linkBtn" imgTag="1"><div class="list-item">1</div></a>
                    <a class="linkBtn" imgTag="2"><div class="list-item">2</div></a>
                    <a class="linkBtn" imgTag="3"><div class="list-item">3</div></a>
                </div>
            </div>

            <button class="list-item">: <span id="previewSpan" style="font-weight: bold;">On</span></button>
        </div>
    </div>`)
    const insertDiv = () =>
    {
        if (GM_getValue("switchButton")) document.querySelector("#end").insertAdjacentElement("afterbegin", div);
        else document.querySelector("#start").append(div);
    }
    insertDiv();

    const ytC = document.querySelector("#ytCover");
    const ytLH = document.querySelector("#ytListHead");
    const Lang = { cover: {en:"Cover", tc:"封面", sc:"封面"},
               preview: {en:"Preview", tc:"圖片預覽", sc:"图片预览"},
                    on: {en:"On", tc:"開", sc:"开"},
                   off: {en:"Off", tc:"關", sc:"关"},
          switchButton: {en:"Switch Button Position", tc:"切換按鈕位置", sc:"切换按钮位置"}};
    const usedLang = document.documentElement.lang.match(/zh/i) ?
                        (document.documentElement.lang.match(/cn/i) ? "sc":"tc") : "en"

    GM_registerMenuCommand(Lang.switchButton[usedLang], () =>
    {
        GM_setValue("switchButton", !GM_getValue("switchButton"));
        insertDiv();
    });


    ytC.innerText = Lang.cover[usedLang];
    ytLH.style.width = usedLang=="en"?"10em":"10.4em";

    window.onresize = () =>
    {
        ytLH.style.left = (ytC.getXY().X/10-1)+"em";
        if(window.innerWidth<1350)
        {
            if(window.innerWidth>850)div.style.margin = `0 ${3*((window.innerWidth-500)/850)}em`;
            else div.style.margin = "0 1em";
        }
        else
        {div.style.margin = "0 3em"}
    }

    document.querySelectorAll(".list > .slide").forEach((e)=>
    {
        const list = e.querySelector(".list");
        e.onmouseenter = () =>
        {
            list.style.top = (e.getXY().Y/10-0.5)+"em";
            list.style.left = parseFloat(ytLH.style.left) + parseFloat(ytLH.style.width) + "em";
            list.hidden = false;
        };
        e.onmouseleave = () => {list.hidden = true}
    });

    const preview = document.createElement("img");
    preview.id = "preview";
    preview.hidden = true;
    document.body.append(preview);

    const Btns = document.querySelectorAll(".linkBtn");
    Btns.forEach((e)=>
    {
        e.onmouseenter = () =>
        {
            if(!GM_getValue("previewOn")) return;
            preview.hidden = false;
            preview.src = e.href;
        };
        e.onmouseleave = () => {preview.hidden = true}
        e.target="_blank";
    });

    const previewBtn = document.querySelector(".list > button");
    previewBtn.setHTML(Lang.preview[usedLang] + previewBtn.innerHTML);
    const previewSpan = document.querySelector("#previewSpan");
    const previewBtnChange = () =>
    {
        if (GM_getValue("previewOn"))
        {
            previewSpan.style.color = "green";
            previewSpan.innerText = Lang.on[usedLang];
        }
        else
        {
            previewSpan.style.color = "red";
            previewSpan.innerText = Lang.off[usedLang];
        }
    };
    previewBtn.onclick = () =>
    {
        GM_setValue("previewOn", !GM_getValue("previewOn"));
        previewBtnChange();
    }
    previewBtnChange();


    let hide;
    ytC.onmouseenter = () =>
    {
        hide = false;
        ytLH.hidden = false;
        window.onresize();
    };
    ytC.onmouseleave = () =>
    {
        hide = true;
        delay(500).then(()=>{ytLH.hidden = hide});
    };
    ytLH.onmouseenter = () =>
    {
        hide = false;
    };
    ytLH.onmouseleave = () =>
    {
        hide = true;
        delay(200).then(()=>{ytLH.hidden = hide});
    };

    let oldHref;
    const onPageUpdate = () =>
    {
        if (oldHref == location.href) return
        oldHref = location.href

        console.log("[Youtube Cover] detect page updated")

        const video_id = location.href.match(/(?<=v=)[^&]{11}|(?<=\/shorts\/).{11}/);
        ytC.hidden = !video_id;
        if (!video_id) return;

        document.querySelectorAll(".list-item > .list").forEach((e)=>
        {
            e.parentNode.hidden = true;
            e.querySelectorAll(".linkBtn").forEach((forEachBtn)=>
            {
                const imgSizeSpec = forEachBtn.getAttribute("imgTag") ?? forEachBtn.innerText
                checkImg(`https://i.ytimg.com/vi/${video_id}/${imgSizeSpec}.jpg`).then((notHide)=>
                {
                    forEachBtn.hidden = !notHide;
                    if(notHide) e.parentNode.hidden = false;
                });
                forEachBtn.href = `https://i.ytimg.com/vi/${video_id}/${imgSizeSpec}.jpg`
            });
        });
    }

    document.addEventListener("yt-rendererstamper-finished", onPageUpdate)
    document.addEventListener("yt-page-type-changed", onPageUpdate)
    document.addEventListener("yt-navigate-start", onPageUpdate)
    waitElementLoad("yt-page-navigation-progress",1,20,250)
        .then((e)=>{new MutationObserver(onPageUpdate).observe(e, {attributes: true})})

    console.log("[Youtube Cover] done");
}

console.log("[Youtube Cover] loading");
waitElementLoad("#start", 1, 10, 300).then(main)