@jsquash/resize

An easy experience for resizing images in the browser or V8 environment. Powered by WebAssembly ⚡️ and Rust.

ℹ️ You will need to have an already decoded ImageData object to resize. This can be accomplished by using other jSquash modules or using the Canvas API, if available.

Uses squoosh's Resize module. Composed of:

• https://github.com/PistonDevelopers/resize
• https://github.com/CryZe/wasmboy-rs/tree/master/hqx

A jSquash package. Codecs and supporting code derived from the Squoosh app.

Installation

npm install --save @jsquash/resize
# Or your favourite package manager alternative

Usage

Note: You will need to either manually include the wasm files from the codec directory or use a bundler like WebPack or Rollup to include them in your app/server.

resize(data: ImageData, options: ResizeOptions): Promise

Resizes an ImageData object to the

data

Type: ImageData

options

Type: Partial<ResizeOptions> & { width: number, height: number }

The resize options for the output image. See default values.

• width (number) the width to resize the image to
• height (number) the height to resize the image to
• method? ('triangle' | 'catrom' | 'mitchell' | 'lanczos3' | 'hqx') the algorithm used to resize the image. Defaults to lanczos3.
• fitMethod? ('stretch' | 'contain') whether the image is stretched to fit the dimensions or cropped. Defaults to stretch.
• premultiply? (boolean) Defaults to true
• linearRGB? (boolean) Defaults to true

Example

import { decode } from '@jsquash/jpeg';
import resize from '@jsquash/resize';

const imageBuffer = fetch('/images/example.jpg').then(res => res.arrayBuffer());
const originalImageData = await decode(imageBuffer);
const resizedImageData = await resize(originalImageData, { height: 300, width: 400 };

Manual WASM initialisation (not recommended)

In most situations there is no need to manually initialise the provided WebAssembly modules. The generated glue code takes care of this and supports most web bundlers.

One exception is CloudFlare workers. The environment at this time (this could change in the future) does not allow code to be dynamically imported. It needs to be bundled at runtime. WASM modules are set as global variables. See the Cloudflare workers example.

The main module exports initHqx and initResize functions that can be used to manually load their respective wasm module.

import resize, { initResize } from '@jsquash/resize';

const WASM_MODULE = // A WebAssembly.Module object of the compiled wasm binary
initResize(WASM_MODULE);

resize(image, options);