html-squircle

html-squircle is a lightweight, framework-agnostic JavaScript package designed to create superellipse squircles (smooth, rounded shapes) that can be used as SVG clip paths or backgrounds for web elements. This package is perfect for developers looking to add modern, beautifully-rounded corners to the web with minimal effort.

Features

• Generate squircles as SVG strings for use in clip-path or background-image inline styles.
• Unlike a true superellipse, transitions gracefully into straight edges, making it suitable for UI elements of various sizes.
• Customizable curve length, curve smoothness, background (solid color or gradient), stroke color, stroke width, and SVG injections to defs or body.
• Easy to use with any web framework or vanilla JavaScript.
• Exports React hooks that will cache results across components and sync with the size of an element.

Installation

You can install html-squircle using npm:

npm install html-squircle

Usage

After installing html-squircle, you can import and use it in your project as follows:

import { clipSquircle, backgroundSquircle } from "html-squircle"
import type { SquircleOptionsSVG } from "html-squircle"

const squircleSquare200: SquircleOptionsSVG = {
  width: 200,
  height: 200,
  stroke: "black",
  strokeWidth: 2,
  background: "#ff6347"
}

// Example usage for a clip path
const clipPathStyle = clipSquircle(squircleSquare200)
document.getElementById("yourElementId").style.clipPath = clipPathStyle

// Example usage for a background with a solid color
const backgroundStyle = backgroundSquircle(squircleSquare200)
document.getElementById("anotherElementId").style.backgroundImage =
  backgroundStyle

The default values for curveLength (calculated based on shortest side) and roundness (0.2) will produce shapes exactly like Apple's app icons when the width and height are equal.

For React, useClipSquircle and useBackgroundSquircle are also exported. These accept the usual params, excluding width and height, since those are measured and kept in sync for you, and a ref for the element to be measured. For both, there's no need to ensure the input params have stable references. For improved performance, they also memoize the results across components for you automatically.

Tips

When trying to control the sharpness of the curve, first adjust the curveLength parameter. If you're not getting the result you want, then reach for roundness.

The backgroundSquircle function is only really useful if you need to add a stroke to your background (regular CSS border will be clipped if you use clip-path), or if you need to do something else fancy with SVG (see below).

Use the injectedDefs and injectedBody params if you need to do anything custom with the generated background SVG. This must be a string. You can refer to other elements of the SVG in <use /> elements by referring to their ids: #path, #rect, #clip, #mask, #grad. To create xml tag structures easily, you can use the exported tag function. For maximum browser support and to align with the rest of the SVG result, always use single quotes. Your input will be URI-encoded for you, so don't do this yourself.

The values can be partly animated with CSS. The width and height will smoothly transition, but the curves will fade from one definition to the next.