@saschazar/wasm-image-loader
v4.0.0
Published
Loads and resizes images using WebAssembly
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📦 WebAssembly image loader/resizer
A dependency-free image loader/resizer written in WebAssembly
It works primarily as JPEG/PNG decoder, but might as well load 'raw' images from a Uint8Array
to resize them to a desired width/height.
Installation
yarn add @saschazar/wasm-image-loader
or
npm install --save @saschazar/wasm-image-loader
Usage
It supports usage in the browser, in a Web Worker and of course Node.js.
// Node.js
import wasm_image_loader from '@saschazar/wasm-image-loader';
// Web Worker - see: https://developer.mozilla.org/en-US/docs/Web/API/WorkerGlobalScope/importScripts
importScripts('wasm_image_loader.js');
// -------- Browser/Web Worker/Node.js code below --------
// Load an image into a buffer using the Fetch API
const buffer = fetch('some JPEG or PNG').then((res) => res.buffer());
// Initialize the WebAssembly Module
const imageLoaderModule = new Promise((resolve) => {
const wasm = wasm_image_loader({
onRuntimeInitialized() {
// remove the 'then' property from wasm_image_loader,
// otherwise Promise runs into an endless loop.
const { then, ...other } = wasm;
// let Promise resolve with 'other' properties.
resolve(other);
},
});
});
async function loadImage() {
// store image buffer in Uint8Array
const array = new Uint8Array(await buffer());
const channels = 3; // 3 if RGB, 4 if Alpha channel is present (e.g. PNG)
// let imageLoaderModule Promise resolve
const { decode, dimensions, free, resize } = await imageLoaderModule;
const decoded = decode(array, array.length, channels);
const { channels, height, width } = dimensions();
const resized = resize(decoded, width, height, channels, 800, 600);
console.log(resized); // logs the uncompressed 800x600 RGB Uint8Array
// clean up memory, when loader is not needed anymore
free();
}
Example
A working example is available on RunKit.
Credits
This package uses nothings/stb's source code (stb_image.h
and stb_image_resize.h
in particular).
License
Licensed under the MIT license.
Copyright ©️ 2020—2021 Sascha Zarhuber