blurhash-to-css

blurhash-to-css

Converts a BlurHash to a CSS Object using TypeScript, Rust, and WebAssembly.

🌩 Installation

npm install blurhash-to-css

📣 Summary

BlurHash is a compact representation of a placeholder for an image, which makes it a great option to improve perceived load times. But, a BlurHash is rendered using a <canvas> element, which means client-side JavaScript is needed on the critical path when loading our application.

This tool creates the same visual effect using CSS, which can be rendered on the Server without any dependency on client-side JavaScript.

An example can be seen at https://blurhash-to-css.vercel.app and the source is in this repo at /example.

🤝 Credit

• The image buffer to CSS conversion is a port to Rust of this Script originally by @joe-bell for plaiceholder: Beautiful image placeholders, without the hassle.
• A lot of help came from the source code in wasm-image by @acidicX.

🕹 Usage

import { blurhashToCss } from 'blurhash-to-css';

const css = blurhashToCss('eCF6B#-:0JInxr?@s;nmIoWUIko1%NocRk.8xbIUaxR*^+s;RiWAWU');

↓↓↓↓↓

{
  "backgroundImage": "linear-gradient(90deg, rgb(139,153,96) 10%,rgb(153,160,118) 10% 20%,rgb(170,172,142) 20% 30%,rgb(177,180,151) 30% 40%,rgb(174,180,146) 40% 50%,rgb(162,172,130) 50% 60%,rgb(148,162,114) 60% 70%,rgb(136,150,104) 70% 80%,rgb(131,145,95) 80% 90%,rgb(130,144,91) 90% 100%),linear-gradient(90deg, rgb(109,129,65) 10%,rgb(117,131,80) 10% 20%,rgb(130,138,101) 20% 30%,rgb(142,148,113) 30% 40%,rgb(146,150,114) 40% 50%,rgb(136,144,103) 50% 60%,rgb(116,130,88) 60% 70%,rgb(102,119,75) 70% 80%,rgb(104,118,71) 80% 90%,rgb(112,123,72) 90% 100%),linear-gradient(90deg, rgb(110,122,70) 10%,rgb(114,122,85) 10% 20%,rgb(126,129,106) 20% 30%,rgb(143,140,122) 30% 40%,rgb(151,147,128) 40% 50%,rgb(144,142,122) 50% 60%,rgb(123,126,107) 60% 70%,rgb(106,111,90) 70% 80%,rgb(108,109,83) 80% 90%,rgb(118,117,83) 90% 100%),linear-gradient(90deg, rgb(134,133,102) 10%,rgb(141,138,120) 10% 20%,rgb(155,150,144) 20% 30%,rgb(172,164,161) 30% 40%,rgb(179,173,168) 40% 50%,rgb(173,168,162) 50% 60%,rgb(156,151,146) 60% 70%,rgb(137,132,127) 70% 80%,rgb(127,124,110) 80% 90%,rgb(128,124,101) 90% 100%),linear-gradient(90deg, rgb(116,124,95) 10%,rgb(125,129,112) 10% 20%,rgb(143,141,135) 20% 30%,rgb(160,156,153) 30% 40%,rgb(169,164,160) 40% 50%,rgb(165,161,155) 50% 60%,rgb(148,145,141) 60% 70%,rgb(124,125,118) 70% 80%,rgb(107,110,97) 80% 90%,rgb(99,106,82) 90% 100%),linear-gradient(90deg, rgb(95,105,51) 10%,rgb(99,105,66) 10% 20%,rgb(110,111,88) 20% 30%,rgb(125,122,107) 30% 40%,rgb(136,131,115) 40% 50%,rgb(134,129,111) 50% 60%,rgb(120,116,98) 60% 70%,rgb(97,97,77) 70% 80%,rgb(78,84,51) 80% 90%,rgb(70,78,30) 90% 100%),linear-gradient(90deg, rgb(109,106,21) 10%,rgb(109,104,44) 10% 20%,rgb(112,104,67) 20% 30%,rgb(122,109,83) 30% 40%,rgb(131,114,88) 40% 50%,rgb(130,112,83) 50% 60%,rgb(119,103,70) 60% 70%,rgb(104,91,51) 70% 80%,rgb(93,84,34) 80% 90%,rgb(92,84,24) 90% 100%)",
  "backgroundPosition": "0 0 ,0 16.666666666666664%,0 33.33333333333333%,0 50%,0 66.66666666666666%,0 83.33333333333334%,0 100%",
  "backgroundSize": "100% 14.285714285714286%",
  "backgroundRepeat": "no-repeat",
  "filter": "blur(24px)",
  "transform": "scale(1.2)"
}

To use this a CommonJS project, you should destructure it like so:

const { blurhashToCss } = require('blurhash-to-css');

🛠 Options

blurhash (required)

A small string (or array of strings) generated to represent a blurry version of an image which will download sometime soon. Have a play around on BlurHash, plaiceholder.co, and have a read of BlurHash for imgix: An Alternative to Generic Image Placeholders to try them out and find out more.

width and height (optional)

The BlurHash is decoded into a 10 x 10 image by default, you can make this larger and it will look more like the final image, but it will also generate a lot more CSS.

const css = blurhashToCss('LEHLh[WB2yk8pyoJadR*.7kCMdnj', {
  height: 30,
  width: 30,
});

Changelog

0.5.5 (2022-11-12)

Bug Fixes

• cargo: update dependencies (3c6e1d7)
• npm: update dependencies (e43dec9)

Features

• blurhash: accept arrays of blurhashes (3afacfc)