imgur embed rewriter

Rewrites imgur image embeds to a rimgo instance

You will need to install an extension such as Tampermonkey, Greasemonkey or Violentmonkey to install this script.

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

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

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

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

You will need to install a user script manager extension to install this script.

(I already have a user script manager, let me install it!)

You will need to install an extension such as Stylus to install this style.

You will need to install an extension such as Stylus to install this style.

You will need to install an extension such as Stylus to install this style.

You will need to install a user style manager extension to install this style.

You will need to install a user style manager extension to install this style.

You will need to install a user style manager extension to install this style.

(I already have a user style manager, let me install it!)

// ==UserScript==
// @name         imgur embed rewriter
// @namespace    http://tampermonkey.net/
// @version      1.0
// @description  Rewrites imgur image embeds to a rimgo instance
// @match        *://*/*
// @run-at       document-end
// @grant        GM_registerMenuCommand
// @grant        GM_getValue
// @grant        GM_setValue
// ==/UserScript==
(function () {
    'use strict';
    const defaults = { badge: true, position: 'top-right', style: 'white-shadow', instance: 'https://rimgo.example.com' };
    function get(key) { return GM_getValue(key, defaults[key]); }
    function getRimgo() { return get('instance').replace(/\/+$/, ''); }
    const IMGUR = /https?:\/\/(\w+\.)?imgur\.com\/(\w+)+(\.[a-zA-Z]{3,4})/;
    function badgeCSS() {
        const positions = {
            'top-right':    'top:6px;right:6px;',
            'top-left':     'top:6px;left:6px;',
            'bottom-right': 'bottom:6px;right:6px;',
            'bottom-left':  'bottom:6px;left:6px;',
        };
        const filters = {
            'white-shadow': 'invert(1) drop-shadow(0px 1px 3px rgba(0,0,0,0.9))',
            'grey':         'grayscale(1) brightness(1.4) drop-shadow(0px 1px 2px rgba(0,0,0,0.5))',
            'dark':         'brightness(0.2) drop-shadow(0px 1px 2px rgba(255,255,255,0.5))',
        };
        return `position:absolute;${positions[get('position')]}width:18px;height:18px;opacity:0.85;filter:${filters[get('style')]};pointer-events:none;z-index:9999;`;
    }
    function addBadge(el) {
        if (!get('badge') || el.dataset.rimgoBadge) return;
        el.dataset.rimgoBadge = '1';
        const wrapper = document.createElement('div');
        wrapper.style.cssText = 'position:relative;display:inline-block;';
        const badge = document.createElement('img');
        badge.src = `${getRimgo()}/static/img/rimgo.svg`;
        badge.dataset.rimgo = '1';
        badge.style.cssText = badgeCSS();
        el.parentNode.insertBefore(wrapper, el);
        wrapper.appendChild(el);
        wrapper.appendChild(badge);
    }
    function redirectImg(el) {
        if (el.dataset.rimgo) return;
        if (!IMGUR.test(el.src)) return;
        el.dataset.rimgo = '1';
        el.src = el.src.replace(/https?:\/\/(\w+\.)?imgur\.com/, getRimgo());
        addBadge(el);
    }
    function walk(root) {
        const walker = document.createNodeIterator(
            root,
            NodeFilter.SHOW_ELEMENT,
            node => node.nodeName === 'IMG' ? NodeFilter.FILTER_ACCEPT : NodeFilter.FILTER_SKIP
        );
        let node;
        while ((node = walker.nextNode())) {
            redirectImg(node);
        }
    }
    const observer = new MutationObserver(mutations => {
        for (const mutation of mutations) {
            for (const node of mutation.addedNodes) {
                if (node.nodeType !== Node.ELEMENT_NODE) continue;
                if (node.nodeName === 'IMG') redirectImg(node);
                else walk(node);
            }
        }
    });
    walk(document.body);
    observer.observe(document.body, { childList: true, subtree: true });

    GM_registerMenuCommand(`Instance: ${get('instance')} — change`, () => {
        const current = get('instance');
        const next = prompt('Enter rimgo instance URL:', current);
        if (next && next.trim()) {
            GM_setValue('instance', next.trim().replace(/\/+$/, ''));
            location.reload();
        }
    });
    GM_registerMenuCommand(`Badge: ${get('badge') ? 'on' : 'off'} — toggle`, () => {
        GM_setValue('badge', !get('badge')); location.reload();
    });
    GM_registerMenuCommand(`Position: ${get('position')} — change`, () => {
        const o = ['top-right','top-left','bottom-right','bottom-left'];
        GM_setValue('position', o[(o.indexOf(get('position')) + 1) % o.length]); location.reload();
    });
    GM_registerMenuCommand(`Style: ${get('style')} — change`, () => {
        const o = ['white-shadow','grey','dark'];
        GM_setValue('style', o[(o.indexOf(get('style')) + 1) % o.length]); location.reload();
    });
})();