Hover preview for links to other comments
// ==UserScript==
// @name Derpibooru Comment Preview
// @description Hover preview for links to other comments
// @version 1.0.20
// @author Marker
// @namespace https://github.com/marktaiwan/
// @homepageURL https://github.com/marktaiwan/Derpibooru-Link-Preview
// @supportURL https://github.com/marktaiwan/Derpibooru-Link-Preview/issues
// @include /^https?://(www\.)?(derpiboo\.ru|derpibooru\.org|trixiebooru\.org)/(images/)?\d{1,}(\?|\?.{1,}|/|\.html)?$/
// @include /^https?://(www\.)?(derpiboo\.ru|derpibooru\.org|trixiebooru\.org)/lists/user_comments/\d{1,}(\?|\?.{1,}|/|\.html)?$/
// @include /^https?://(www\.)?(derpiboo\.ru|derpibooru\.org|trixiebooru\.org)/lists/my_comments(\?|\?.{1,}|/|\.html)?$/
// @grant none
// ==/UserScript==
(function() {
'use strict';
function displayHover(comment, link) {
const PADDING = 5; // px
if (!hover) return;
// hack for preventing mulltiple previews from appearing due to fetch()
var preview = document.querySelectorAll('#hover_preview');
if (preview !== null) {
for (i = 0; i < preview.length; i++) {
preview[i].parentNode.removeChild(preview[i]);
}
}
comment = comment.cloneNode(true);
comment.id = 'hover_preview';
comment.style.position = 'absolute';
comment.style.maxWidth = '980px';
comment.style.minWidth = '490px';
// Make spoiler visible
var i;
var list = comment.querySelectorAll('span.spoiler, span.imgspoiler, span.imgspoiler img');
if (list !== null) {
for (i = 0; i < list.length; i++) {
if (list[i].matches('span')) {
list[i].style.color = '#333';
list[i].style.backgroundColor = '#f7d4d4';
} else {
list[i].style.visibility = 'visible';
}
}
}
var container = document.getElementById('image_comments') || document.getElementById('content');
if (container) container.appendChild(comment);
// calculate link position
var linkRect = link.getBoundingClientRect();
var linkTop = linkRect.top + viewportPos().top;
var linkLeft = linkRect.left + viewportPos().left;
var commentRect = comment.getBoundingClientRect();
var commentTop;
var commentLeft;
// When there is room, place the preview above the link
// otherwise place it to the right and aligns it to the top of viewport
if (linkRect.top > commentRect.height + PADDING) {
commentTop = linkTop - commentRect.height - PADDING;
commentLeft = linkLeft;
} else {
commentTop = viewportPos().top + PADDING;
commentLeft = linkLeft + linkRect.width + PADDING;
}
comment.style.top = commentTop + 'px';
comment.style.left = commentLeft + 'px';
}
function linkEnter(e) {
// filtering
if (!e.target.matches('.communication__body__text a[href*="#comment_"], .communication__body__text a[href*="#comment_"]>*')) return;
// Example: e.target.hash == "#comment_5430424"
var sourceLink = e.target.parentNode.matches('a[href*="#comment_"]') ? e.target.parentNode : e.target;
var targetID = sourceLink.hash.slice(9);
var targetComment = document.getElementById('comment_' + targetID);
// ignore quotes
// this is terrible
if (sourceLink.nextElementSibling &&
sourceLink.nextElementSibling.nextElementSibling &&
sourceLink.nextElementSibling.nextElementSibling.matches('blockquote')) return;
hover = true;
if (targetComment !== null) {
// Post exist on current page
if (!elementInViewport(targetComment)) displayHover(targetComment, sourceLink);
// Highlight linked post
targetComment.firstChild.style.backgroundColor = 'rgba(230,230,30,0.3)';
} else {
// External post, display from cached response if possible
if (fetchCache[targetID] !== undefined) {
displayHover(fetchCache[targetID], sourceLink);
} else {
fetch(window.location.origin + '/comment/' + targetID + '.html')
.then((response) => response.text())
.then((text) => {
var d = document.createElement('div');
d.innerHTML = text;
fetchCache[targetID] = d.firstChild;
displayHover(d.firstChild, sourceLink);
});
}
}
}
function linkLeave(e) {
// filtering
if (!e.target.matches('.communication__body__text a[href*="#comment_"], .communication__body__text a[href*="#comment_"]>*')) return;
hover = false;
var i;
var sourceLink = e.target.parentNode.matches('a[href*="#comment_"]') ? e.target.parentNode : e.target;
var targetID = sourceLink.hash.slice(9);
var targetComment = document.getElementById('comment_' + targetID);
var preview = document.getElementById('hover_preview');
// ignore quotes
// this is still terrible
if (sourceLink.nextElementSibling &&
sourceLink.nextElementSibling.nextElementSibling &&
sourceLink.nextElementSibling.nextElementSibling.matches('blockquote')) return;
//remove highlight
if (targetComment !== null) targetComment.firstChild.style.backgroundColor = '';
if (preview !== null) preview.parentNode.removeChild(preview);
}
// Chrome/Firefox compatibility hack for getting viewport position
function viewportPos() {
return {
top: (document.documentElement.scrollTop || document.body.scrollTop),
left: (document.documentElement.scrollLeft || document.body.scrollLeft)
};
}
function elementInViewport(el) {
var rect = el.getBoundingClientRect();
return (
rect.top >= 0 &&
rect.left >= 0 &&
rect.bottom <= (window.innerHeight || document.documentElement.clientHeight) &&
rect.right <= (window.innerWidth || document.documentElement.clientWidth)
);
}
var hover = false;
var fetchCache = {};
var container = document.getElementById('image_comments') || document.getElementById('content');
if (container) {
container.addEventListener('mouseover', linkEnter);
container.addEventListener('mouseout', linkLeave);
}
})();