README.md

Pop Out!

This custom element combo provides a scrollable element with child elements that expand out of the overflow area when hovered. It was created in response to a long-standing issue with the CSS spec and this question on Stack Overflow.

How it Works

The child elements are plucked out from the static context and positioned fixed to the viewport while simultaneously inserting a placeholder of the same dimensions into the static context to prevent the layout from collapsing.

Usage

<script type="module" src="./pop-out.js"></script>
<over-scroll>
  <pop-out><img src="./your.png"></pop-out>
  <pop-out><img src="./content.svg"></pop-out>
  <pop-out><img src="./here.jpg"></pop-out>
</over-scroll>

Both element definitions are imported by the single script tag. You can also import the classes into your script and create these programatically.

import { OverScrollElement, PopOutElement } from './pop-out.js';

let overScroll = new OverScrollElement();
let popOut = new PopOutElement();
popOut.innerHTML = `<h1> Hello! </h1>`;
overScroll.append(popOut);
document.body.append(overScroll);

The outer, over-scroll element is necessary to enable scroll events to pass through the nested elements and gracefully de-zoom the active element. The default mode is to scroll horizontally. Adding a vertical attribute modifies the scroll direction and makes it display:inline-flex.

<over-scroll vertical>
   ...
</over-scroll>

You can pass any markup/elements you want into pop-out though images and center justified content tend to work best. You have full control over the styling of your content. A few default rules are applied to pop-out elements that can be overriden:

pop-out {
  display: block;
  cursor: zoom-in;
  user-select: none;
  --scale-amount: 1.5;
  --scale-speed: 0.2s;
  --scale-timing: ease;
  --shadow-in: drop-shadow(0 0 0.2rem #00000033);
  --shadow-out: drop-shadow(0 0 1rem #00000088);
}