Link Preview

<p class="kodza-link-preview-text">We built Kodza in a room shaped like <a class="kodza-link-preview" href="#" data-preview-image="https://kodza.dev/media/kz-arch-1400.webp" data-preview-title="The arch" data-preview-url="kodza.dev/rooms/arch">an arch</a>, under <a class="kodza-link-preview" href="#" data-preview-image="https://kodza.dev/media/kz-columns-1400.webp" data-preview-title="Seven columns, no meetings" data-preview-url="kodza.dev/rooms/columns">seven columns</a>, next to <a class="kodza-link-preview" href="#" data-preview-image="https://kodza.dev/media/kz-steps-1400.webp" data-preview-title="Stairs that lead nowhere" data-preview-url="kodza.dev/rooms/stairs">stairs that lead nowhere</a>.</p>

/* Kodza License: free to use, client work included. Not to resell or redistribute, ported or not: https://kodza.dev/docs/#print-license */
/* Kodza — Link Preview
   Point at a link and a card of where it goes unfolds above it: a picture, a title and the
   address. One card per paragraph: move to the next link and it glides there, the picture
   cross-fading and the words rolling, instead of closing and opening again. It follows the
   pointer along the link with a little lag; on focus it shows above the link; on touch
   screens the link is just a link. Set data-preview-image, -title and -url on each link.
   Everything is tuned with the --kz-preview-* variables. */
.kodza-link-preview-text {
  position: relative;
}

.kodza-link-preview {
  --kz-preview-line: color-mix(in srgb, currentColor 30%, transparent);

  color: inherit;
  text-decoration: underline;
  text-decoration-color: var(--kz-preview-line);
  text-decoration-thickness: 0.06em;
  text-underline-offset: 0.2em;
  transition: text-decoration-color 0.3s ease;
}

.kodza-link-preview:hover,
.kodza-link-preview:focus-visible,
.kodza-link-preview.is-current {
  text-decoration-color: currentColor;
}

.kodza-link-preview:focus-visible {
  outline: 2px solid currentColor;
  outline-offset: 3px;
  border-radius: 3px;
}

/* The card: placed by the script; its shadow follows what is shown of it */
.kodza-link-preview__card {
  --kz-preview-bg: #ffffff;
  --kz-preview-fg: #0a0a0a;
  --kz-preview-muted: rgba(10, 10, 10, 0.6);
  --kz-preview-border: rgba(10, 10, 10, 0.1);
  --kz-preview-shadow: rgba(10, 10, 10, 0.28);
  --kz-preview-width: 240px;
  --kz-preview-ease: cubic-bezier(0.22, 1, 0.36, 1);

  position: absolute;
  top: 0;
  left: 0;
  z-index: 20;
  width: var(--kz-preview-width);
  color: var(--kz-preview-fg);
  font-size: 14px;
  font-weight: 400;
  letter-spacing: 0;
  line-height: 1.4;
  text-align: left;
  pointer-events: none;
  filter: drop-shadow(0 18px 24px var(--kz-preview-shadow));
  transform: translate(var(--kz-preview-x, 0px), var(--kz-preview-y, 0px));
}

/* It unfolds upwards from the link, like a curtain rising */
.kodza-link-preview__body {
  display: grid;
  overflow: hidden;
  border-radius: 14px;
  background: var(--kz-preview-bg);
  box-shadow: inset 0 0 0 1px var(--kz-preview-border);
  clip-path: inset(100% 0 0 0 round 14px);
  transition: clip-path 0.32s cubic-bezier(0.65, 0, 0.35, 1);
}

.kodza-link-preview__card.is-open .kodza-link-preview__body {
  clip-path: inset(0 0 0 0 round 14px);
  transition: clip-path 0.55s var(--kz-preview-ease);
}

.kodza-link-preview__media {
  display: grid;
  aspect-ratio: 16 / 10;
  overflow: hidden;
  background: var(--kz-preview-border);
}

.kodza-link-preview__media img {
  grid-area: 1 / 1;
  width: 100%;
  height: 100%;
  object-fit: cover;
  transform: scale(1.14);
  transition: transform 0.9s var(--kz-preview-ease);
}

.kodza-link-preview__card.is-open .kodza-link-preview__media img {
  transform: none;
}

/* Title and address: their words roll when the card moves to another link */
.kodza-link-preview__title,
.kodza-link-preview__url {
  display: grid;
  overflow: hidden;
}

.kodza-link-preview__title > span,
.kodza-link-preview__url > span {
  grid-area: 1 / 1;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.kodza-link-preview__title {
  padding: 12px 14px 0;
  font-weight: 600;
  letter-spacing: -0.01em;
}

.kodza-link-preview__url {
  padding: 2px 14px 12px;
  color: var(--kz-preview-muted);
  font-family: "Geist Mono", ui-monospace, "SF Mono", Menlo, monospace;
  font-size: 11.5px;
}

@media (prefers-reduced-motion: reduce) {
  .kodza-link-preview,
  .kodza-link-preview__body,
  .kodza-link-preview__media img {
    transition-duration: 0.01ms !important;
  }
}

/* Theming example — on a dark background:
.dark-section .kodza-link-preview__card {
  --kz-preview-bg: #161616;
  --kz-preview-fg: #f2f2f0;
  --kz-preview-muted: rgba(242, 242, 240, 0.6);
  --kz-preview-border: rgba(255, 255, 255, 0.12);
  --kz-preview-shadow: rgba(0, 0, 0, 0.7);
}
*/

/* kodza-guard 8fa0499787ae — generated by Kodza, do not edit.
   Theme guard: keeps a site's own CSS (WordPress themes, Bootstrap, CSS resets…) off this
   component. :not(#_) is always true and weighs as much as an id, so these lines win over
   theme rules made of classes and tags. Customise the component through its --kz-* variables. */

/* What the browser gives, where the component sets it only in some states: at the lowest weight, so its own rules below put it back */

:where(.kodza-link-preview):not(#_) {
  border-radius: revert;
  outline: revert;
  outline-offset: revert;
}

/* What the browser gives, on everything the component leaves to it */

.kodza-link-preview:not(#_) {
  border: revert;
  padding: revert;
  list-style: revert;
  box-sizing: revert;
  position: revert;
  background-color: revert;
  background-image: revert;
  box-shadow: revert;
  appearance: revert;
  max-height: revert;
  font-family: revert;
  font-size: revert;
  font-weight: revert;
  font-style: revert;
  line-height: revert;
  letter-spacing: revert;
  text-transform: revert;
  text-align: revert;
  text-indent: revert;
  text-shadow: revert;
  vertical-align: revert;
}

.kodza-link-preview:not(#_):where(:not([hidden])) {
  display: revert;
}

.kodza-link-preview:not(#_):where([hidden]) {
  display: none;
}

/* The component's own rules, one step stronger: real buttons and fields, what it sets on tags themes style (links, lists, headings, images…), and the root width (a theme may narrow it, never widen it) */

.kodza-link-preview:not(#_) {
  color: inherit;
  text-decoration: underline;
  text-decoration-color: var(--kz-preview-line);
  text-decoration-thickness: 0.06em;
  text-underline-offset: 0.2em;
  transition: text-decoration-color 0.3s ease;
}

.kodza-link-preview:hover:not(#_),
.kodza-link-preview:focus-visible:not(#_),
.kodza-link-preview.is-current:not(#_) {
  text-decoration-color: currentColor;
}

.kodza-link-preview:focus-visible:not(#_) {
  outline: 2px solid currentColor;
  outline-offset: 3px;
  border-radius: 3px;
}

@media (prefers-reduced-motion: reduce) {
  .kodza-link-preview:not(#_) {
    transition-duration: 0.01ms !important;
  }
}

// Kodza License: free to use, client work included. Not to resell or redistribute, ported or not: https://kodza.dev/docs/#print-license
// Kodza — Link Preview
// One card per paragraph (or per parent of the links): it opens above the link under the
// pointer, follows it with a little lag, and glides to the next link without closing, its
// picture cross-fading and its words rolling. Measured in the paragraph's own pixels, kept on
// screen. Opens on keyboard focus too; no card on touch screens.
(() => {
  const SELECTOR = '.kodza-link-preview';
  const reduceMotion = window.matchMedia('(prefers-reduced-motion: reduce)').matches;
  const finePointer = window.matchMedia('(hover: hover) and (pointer: fine)').matches;
  const ease = 'cubic-bezier(0.22, 1, 0.36, 1)';
  const groups = new Map();

  const roll = (el, text, animate) => {
    const old = el.lastElementChild;
    if (old && old.textContent === text) return;
    const next = Object.assign(document.createElement('span'), { textContent: text });
    el.append(next);
    if (!old) return;
    if (!animate || reduceMotion) return old.remove();
    const timing = { duration: 460, easing: ease };
    old.animate([{ transform: 'none', opacity: 1 }, { transform: 'translateY(-100%)', opacity: 0 }], { ...timing, fill: 'forwards' }).finished.then(() => old.remove());
    next.animate([{ transform: 'translateY(100%)', opacity: 0 }, { transform: 'none', opacity: 1 }], { ...timing, delay: 50, fill: 'backwards' });
  };

  const makeGroup = (group) => {
    const placed = getComputedStyle(group).position === 'static';
    if (placed) group.style.position = 'relative';
    const card = Object.assign(document.createElement('span'), { className: 'kodza-link-preview__card' });
    card.setAttribute('aria-hidden', 'true');
    card.innerHTML = '<span class="kodza-link-preview__body"><span class="kodza-link-preview__media"></span><span class="kodza-link-preview__title"></span><span class="kodza-link-preview__url"></span></span>';
    group.append(card);
    const media = card.querySelector('.kodza-link-preview__media');
    const title = card.querySelector('.kodza-link-preview__title');
    const url = card.querySelector('.kodza-link-preview__url');
    let current = null;
    let open = false;
    let shut = 0;
    let frame = 0;
    let x = 0;
    let y = 0;
    let tx = 0;
    let ty = 0;
    let links = 0;

    const fill = (link) => {
      const { previewImage, previewTitle = '', previewUrl = '' } = link.dataset;
      const animate = open && current && current !== link;
      if (previewImage && media.lastElementChild?.getAttribute('src') !== previewImage) {
        const img = Object.assign(document.createElement('img'), { src: previewImage, alt: '', decoding: 'async' });
        const old = [...media.children];
        media.append(img);
        if (animate && !reduceMotion) {
          img.animate([{ opacity: 0, transform: 'scale(1.08)' }, { opacity: 1, transform: 'none' }], { duration: 560, easing: ease });
          setTimeout(() => old.forEach((el) => el.remove()), 560);
        } else old.forEach((el) => el.remove());
      }
      roll(title, previewTitle, animate);
      roll(url, previewUrl, animate);
    };

    // Above the line of the link under the pointer, centred on it, kept on screen
    const aim = (link, clientX, clientY) => {
      const box = group.getBoundingClientRect();
      const k = box.width / group.offsetWidth || 1;
      const lines = [...link.getClientRects()];
      const line = lines.find((r) => clientY >= r.top && clientY <= r.bottom) || lines[0];
      const w = card.offsetWidth;
      const h = card.offsetHeight;
      const centre = ((clientX ?? line.left + line.width / 2) - box.left) / k;
      tx = Math.min((innerWidth - 12 - box.left) / k - w, Math.max((12 - box.left) / k, centre - w / 2));
      ty = (line.top - box.top) / k - h - 12;
    };
    const glide = () => {
      const k = reduceMotion ? 1 : 0.2;
      x += (tx - x) * k;
      y += (ty - y) * k;
      card.style.setProperty('--kz-preview-x', `${x.toFixed(1)}px`);
      card.style.setProperty('--kz-preview-y', `${y.toFixed(1)}px`);
      frame = Math.abs(tx - x) + Math.abs(ty - y) > 0.4 ? requestAnimationFrame(glide) : 0;
    };

    const show = (link, clientX, clientY) => {
      clearTimeout(shut);
      fill(link);
      aim(link, clientX, clientY);
      // Opening: right there, no slide from wherever it was last
      if (!open) {
        x = tx;
        y = ty;
        card.style.setProperty('--kz-preview-x', `${x}px`);
        card.style.setProperty('--kz-preview-y', `${y}px`);
      }
      current?.classList.remove('is-current');
      current = link;
      link.classList.add('is-current');
      open = true;
      card.classList.add('is-open');
      if (!frame) frame = requestAnimationFrame(glide);
    };
    const hide = (soon = true) => {
      clearTimeout(shut);
      shut = setTimeout(() => {
        open = false;
        card.classList.remove('is-open');
        current?.classList.remove('is-current');
        current = null;
      }, soon ? 140 : 0);
    };

    const add = (link, signal) => {
      links += 1;
      if (finePointer) {
        link.addEventListener('pointerenter', (event) => show(link, event.clientX, event.clientY), { signal });
        link.addEventListener('pointermove', (event) => {
          if (current !== link) return;
          aim(link, event.clientX, event.clientY);
          if (!frame) frame = requestAnimationFrame(glide);
        }, { signal });
        link.addEventListener('pointerleave', () => hide(), { signal });
      }
      link.addEventListener('focus', () => link.matches(':focus-visible') && show(link), { signal });
      link.addEventListener('blur', () => hide(false), { signal });
      link.addEventListener('keydown', (event) => event.key === 'Escape' && hide(false), { signal });
      // A link stopped: the card lets go of it, and leaves with the last one
      signal.addEventListener('abort', () => {
        if (current === link) {
          clearTimeout(shut);
          open = false;
          card.classList.remove('is-open');
          current = null;
        }
        links -= 1;
        if (links) return;
        clearTimeout(shut);
        cancelAnimationFrame(frame);
        card.remove();
        if (placed) group.style.position = '';
        groups.delete(group);
      });
    };
    return { add };
  };

  // One instance. Everything it starts is tied to `signal`, so kodza:destroy stops it all
  function mount(link, signal) {
    if (!link.dataset.previewImage && !link.dataset.previewTitle) return;
    const group = link.closest('.kodza-link-preview-text') || link.parentElement;
    if (!groups.has(group)) groups.set(group, makeGroup(group));
    groups.get(group).add(link, signal);
  }

  // Kodza lifecycle, the same in every component: `kodza:init` starts the instances inside
  // event.detail.root (the whole page by default), `kodza:destroy` stops them and puts their
  // markup back. For themes and apps that swap content without a page load.
  const instances = new WeakMap();
  const find = (scope = document) => [scope, ...scope.querySelectorAll(SELECTOR)].filter((el) => el.matches?.(SELECTOR));
  const init = (scope) => find(scope).forEach((root) => {
    if (root.classList.contains('is-ready')) return; // already running, maybe from another copy of this script
    const controller = new AbortController();
    instances.set(root, { controller, html: root.innerHTML, attrs: [...root.attributes].map((a) => [a.name, a.value]) });
    mount(root, controller.signal);
    root.classList.add('is-ready');
  });
  const destroy = (scope) => find(scope).forEach((root) => {
    const instance = instances.get(root);
    if (!instance) return;
    instances.delete(root);
    instance.controller.abort();
    [...root.attributes].forEach((a) => root.removeAttribute(a.name));
    instance.attrs.forEach(([name, value]) => root.setAttribute(name, value));
    root.innerHTML = instance.html;
  });
  document.addEventListener('kodza:init', (event) => init(event.detail?.root));
  document.addEventListener('kodza:destroy', (event) => destroy(event.detail?.root));
  init();
  // Loaded in <head>, the script runs before the markup exists: once more when it is parsed
  if (document.readyState === 'loading') document.addEventListener('DOMContentLoaded', () => init(), { once: true });
})();

'use client';
// Kodza — Link Preview, for React. From https://kodza.dev/components/link-preview/
// Kodza License: free to use, client work included. Not to resell or redistribute, ported or not: https://kodza.dev/docs/#print-license
// Next to this file: link-preview.css and link-preview.js, the component's CSS and JS from Kodza, as they are.
// Yours to edit: the markup is plain JSX below.
// In Kodza's markup it sits in a <p class="kodza-link-preview-text">, which the CSS and the script use too:
// put yours in one for the same result.
// The script changes this markup once React has rendered it (it adds layers, splits text, moves
// nodes), so React must not patch it afterwards. When a prop changes, the key gives React a fresh
// element: kodza:destroy stops the script on the old one, kodza:init starts it on the new one.
import { useRef, useEffect, type ComponentPropsWithoutRef, type ComponentRef, type CSSProperties } from 'react';
import './link-preview.css';

export type LinkPreviewProps = Omit<ComponentPropsWithoutRef<'a'>, "children" | "vars" | "previewImage" | "previewTitle" | "previewUrl"> & {
  /** data-preview-image on the root (default: https://kodza.dev/media/kz-arch-1400.webp) */
  previewImage?: "https://kodza.dev/media/kz-arch-1400.webp" | "https://kodza.dev/media/kz-columns-1400.webp" | "https://kodza.dev/media/kz-steps-1400.webp";
  /** data-preview-title on the root (default: The arch) */
  previewTitle?: "The arch" | "Seven columns, no meetings" | "Stairs that lead nowhere";
  /** data-preview-url on the root (default: kodza.dev/rooms/arch) */
  previewUrl?: "kodza.dev/rooms/arch" | "kodza.dev/rooms/columns" | "kodza.dev/rooms/stairs";
  /** Settings, as CSS variables on the root */
  vars?: {
    /** default: color-mix(in srgb, currentColor 30%, transparent) */
    "--kz-preview-line"?: string | number;
  };
  /** The text, plain: the script reads it and rebuilds the markup around it */
  children?: string;
  className?: string;
};

export function LinkPreview({ previewImage = "https://kodza.dev/media/kz-arch-1400.webp", previewTitle = "The arch", previewUrl = "kodza.dev/rooms/arch", vars, children = "an arch", className, style, ...rest }: LinkPreviewProps) {
  const ref = useRef<ComponentRef<'a'>>(null);
  const classes = ["kodza-link-preview", className].filter(Boolean).join(' ');
  // Everything the markup is made of: when it changes, React gets a fresh element (see the top)
  const key = JSON.stringify([classes, previewImage, previewTitle, previewUrl, vars, children, style, rest]);

  // Starts the script on this element once React has rendered it, stops it when it goes
  useEffect(() => {
    const root = ref.current;
    let live = true;
    // @ts-ignore: a plain script, no types to find
    import('./link-preview.js').then(() => {
      if (live) document.dispatchEvent(new CustomEvent('kodza:init', { detail: { root } }));
    });
    return () => {
      live = false;
      document.dispatchEvent(new CustomEvent('kodza:destroy', { detail: { root } }));
    };
  }, [key]);

  return (
    <a href="#" key={key} {...rest} className={classes} data-preview-image={previewImage} data-preview-title={previewTitle} data-preview-url={previewUrl} style={{ ...vars, ...style } as CSSProperties} ref={ref}>{children}</a>
  );
}