Zoom function for YouTube

YouTube video zoom feature

当前为 2021-12-31 提交的版本,查看 最新版本

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!)

"use strict";
// ==UserScript==
// @name            Zoom function for YouTube
// @name:ja         YouTubeで動画をズーム
// @description     YouTube video zoom feature
// @description:ja  YouTubeの動画プレイヤーにズーム機能を追加します
// @version         2.0.3
// @include         /https?:\/\/www\.youtube\.com.*/
// @author          sititou70
// @namespace       https://github.com/sititou70/
// @run-at          document-idle
// @license         MIT; https://opensource.org/licenses/MIT
// ==/UserScript==
(function () {
    // consts
    var SCRIPT_NAME = 'youtube video zoom';
    var VIDEO_CONTAINER_SELECTOR = '#movie_player';
    var VIDEO_SELECTOR = VIDEO_CONTAINER_SELECTOR + " video";
    // functions
    var getScaleFromVideo = function (video) {
        var scale_string = video.style.transform.match(/scale\((.+?)\)/);
        if (scale_string === null)
            return 1;
        var scale = parseFloat(scale_string[1]);
        if (isNaN(scale))
            return 1;
        return scale;
    };
    var zoomVideoToRect = function (video, rect) {
        var video_scale = getScaleFromVideo(video);
        var video_client_rect = video.getBoundingClientRect();
        var video_rect = {
            width: video_client_rect.width / video_scale,
            height: video_client_rect.height / video_scale,
        };
        var player_aspect_ratio = video_rect.width / video_rect.height;
        var selected_aspect_ratio = rect.width / rect.height;
        var fit_width = player_aspect_ratio < selected_aspect_ratio; // or height?
        var scale = fit_width
            ? video_rect.width / rect.width
            : video_rect.height / rect.height;
        video.style.transform = "translateX(" + (video_rect.width / 2 - (rect.top_left.x + rect.width / 2)) * scale + "px) translateY(" + (video_rect.height / 2 - (rect.top_left.y + rect.height / 2)) * scale + "px) scale(" + scale + ")";
        video.style.transition = 'all 0.3s ease';
    };
    var drag_start_position;
    var handleDragStart = function (e) {
        var video = e.target;
        var video_rect = video.getBoundingClientRect();
        var scale = getScaleFromVideo(video);
        drag_start_position = {
            x: (e.clientX - video_rect.x) / scale,
            y: (e.clientY - video_rect.y) / scale,
        };
    };
    var handleDragEnd = function (e) {
        var video = e.target;
        var video_rect = video.getBoundingClientRect();
        var scale = getScaleFromVideo(video);
        var drag_end_position = {
            x: (e.clientX - video_rect.x) / scale,
            y: (e.clientY - video_rect.y) / scale,
        };
        var top_left = {
            x: Math.min(drag_start_position.x, drag_end_position.x),
            y: Math.min(drag_start_position.y, drag_end_position.y),
        };
        var bottom_right = {
            x: Math.max(drag_start_position.x, drag_end_position.x),
            y: Math.max(drag_start_position.y, drag_end_position.y),
        };
        var selected_rect = {
            top_left: top_left,
            bottom_right: bottom_right,
            width: bottom_right.x - top_left.x,
            height: bottom_right.y - top_left.y,
        };
        if (selected_rect.width <= 10 || selected_rect.height <= 10)
            return;
        zoomVideoToRect(video, selected_rect);
        video.click();
    };
    var setupZoomFeature = function () {
        var video = document.querySelector(VIDEO_SELECTOR);
        if (video === null)
            return;
        video.addEventListener('mousedown', handleDragStart);
        video.addEventListener('mouseup', handleDragEnd);
    };
    var onKeyPress = function (e) {
        var video = document.querySelector(VIDEO_SELECTOR);
        if (video === null)
            return;
        if (e.key === 'r')
            video.style.transform = '';
    };
    // main
    var main = function () {
        var document_observer = new MutationObserver(setupZoomFeature);
        document_observer.observe(document.body, {
            attributes: true,
        });
        document.addEventListener('keypress', onKeyPress);
    };
    console.log("[" + SCRIPT_NAME + "] loaded.");
    main();
})();