Animated Youtube thumbnails on hover. (Updated)
// ==UserScript==
// @name Animated Youtube Thumbnails Updated
// @namespace YTTN
// @description Animated Youtube thumbnails on hover. (Updated)
// @version 1.0
// @include http://*.youtube.*/*
// @include http://youtube.*/*
// @include https://*.youtube.*/*
// @include https://youtube.*/*
// @grant GM_addStyle
// @grant GM_log
// ==/UserScript==
// If you are interested in YouTube images:
// Thumbnails url looks like http://img.youtube.com/vi/8aYQ_wjmriQ/2.jpg
// Youtube generates 4 thumbnails: 0.jpg at 320x240, and 1.jpg, 2.jpg, 3.jpg
// Also large: hqdefault.jpg (480x360) and sometimes but not always hq1.jpg, hq2.jpg, hq3.jpg
var animateThumbnails = true;
if (animateThumbnails) {
// == Thumbnail animation ==
// TODO: This is working fine on "related videos" thumbnails, but not on queue
// thumbnails, even if I have the queue open when I load the page.
// Perhaps we are responding to a mouseout event from a child element, because
// we are not checking the event target like we should do.
function initThumbnailAnimator() {
// function createThumbnailAnimatorEvent(thumbImage) {
var filenameRE = /\/([^/]*)\.(jpg|webp)(\?.*|$)/;
var thumbImage = null;
var originalHref = null;
var timer = null;
//var frames = ["1.jpg","2.jpg","3.jpg"]; // "default.jpg",
var frames = ["hq1","hq2","hq3"];
var frameI = 0;
function changeFrame() {
frameI = (frameI + 1) % frames.length;
var match = originalHref.match(filenameRE);
var extension = match[2];
var filename = frames[frameI] + '.' + extension;
thumbImage.src = originalHref.replace(filenameRE, '/' + filename);
}
function startAnimation() {
// Because there was a bug that the running animation would not stop!
if (timer) {
clearInterval(timer);
}
originalHref = thumbImage.src;
if (originalHref.match(/^data:/)) {
return;
}
// We make this check quite late, due to lazy loading
if (originalHref.match(filenameRE)) {
// logElem("Starting animation",thumbImage);
timer = setInterval(changeFrame,600);
}
}
function stopAnimation() {
if (timer) {
// logElem("Stopping animation",thumbImage);
clearInterval(timer);
timer = null;
// This isn't really neccessary, except to ensure the check for default\.jpg above works next time!
//thumbImage.src = thumbImage.src.replace(/\/[^/]*$/,'') + '/' + "default.jpg";
thumbImage.src = originalHref;
}
}
function logElem(name,elem) {
report = "<"+elem.tagName+" id="+elem.id+" class="+elem.className+" src="+elem.src+" />";
GM_log(name+" = "+report);
}
function check(fn) {
return function(evt) {
// logElem("["+evt.type+"] evt.target",evt.target);
var elemToCheck = evt.target || evt.srcElement;
if (elemToCheck.tagName == "IMG") {
thumbImage = elemToCheck;
return fn();
} else if (elemToCheck.className=='screen') {
var seekImg = elemToCheck.parentNode.getElementsByTagName("img")[0];
if (seekImg) {
thumbImage = seekImg;
return fn();
}
// } else {
// var imgCount = elemToCheck.getElementsByTagName("img").length;
// if (imgCount == 1) {
// thumbImage = elemToCheck.getElementsByTagName("img")[0];
// // logElem("["+evt.type+"] checking sub-image",thumbImage);
// logElem("Whilst checking",elemToCheck);
// logElem(" Animating elem",thumbImage);
// logElem(" with parent",thumbImage.parentNode);
// logElem(" whilst currentTarget",evt.currentTarget);
// logElem(" and srcElement",evt.srcElement);
// return fn();
// }
}
};
}
//// Unfortunately these do not fire on any HTMLImageElements when browsing the queue.
document.body.addEventListener("mouseover",check(startAnimation),false);
document.body.addEventListener("mouseout",check(stopAnimation),false);
// var videoList = document.getElementById("watch-sidebar"); // or watch-module or watch-module-body or watch-related or watch-more-related
// var videoList = document.getElementsByClassName("video-list")[0]; // can be 4 of these!
// var thumbs = document.getElementsByTagName("img");
// for (var i=0;i<thumbs.length;i++) {
// createThumbnailAnimatorEvent(thumbs[i]);
// }
}
setTimeout(initThumbnailAnimator,1000);
GM_addStyle(" .yt-thumb-simple img, .yt-uix-simple-thumb-related > img { object-fit: cover; } ");
}