@expo/image-utils

What is @expo/image-utils?

@expo/image-utils is a utility package for image processing tasks such as resizing, compressing, and converting images. It is particularly useful in the context of Expo and React Native applications.

What are @expo/image-utils's main functionalities?

Resize Image

This feature allows you to resize an image to specified dimensions. The code sample demonstrates how to read an image from the file system, resize it to 100x100 pixels, and save the resized image back to the file system.

const { resizeImage } = require('@expo/image-utils');
const fs = require('fs');

async function resize() {
  const imageBuffer = fs.readFileSync('path/to/image.jpg');
  const resizedImage = await resizeImage(imageBuffer, { width: 100, height: 100 });
  fs.writeFileSync('path/to/resized-image.jpg', resizedImage);
}
resize();

Compress Image

This feature allows you to compress an image to reduce its file size. The code sample demonstrates how to read an image from the file system, compress it with a quality setting of 0.8, and save the compressed image back to the file system.

const { compressImage } = require('@expo/image-utils');
const fs = require('fs');

async function compress() {
  const imageBuffer = fs.readFileSync('path/to/image.jpg');
  const compressedImage = await compressImage(imageBuffer, { quality: 0.8 });
  fs.writeFileSync('path/to/compressed-image.jpg', compressedImage);
}
compress();

Convert Image Format

This feature allows you to convert an image from one format to another. The code sample demonstrates how to read a JPEG image from the file system, convert it to PNG format, and save the converted image back to the file system.

const { convertImageFormat } = require('@expo/image-utils');
const fs = require('fs');

async function convert() {
  const imageBuffer = fs.readFileSync('path/to/image.jpg');
  const convertedImage = await convertImageFormat(imageBuffer, { format: 'png' });
  fs.writeFileSync('path/to/converted-image.png', convertedImage);
}
convert();

Other packages similar to @expo/image-utils

sharp

Sharp is a high-performance image processing library that supports resizing, cropping, compositing, and format conversion. It is known for its speed and efficiency, making it a popular choice for server-side image processing. Compared to @expo/image-utils, Sharp offers more advanced features and better performance but may be more complex to set up and use.

jimp

Jimp is a JavaScript image processing library that works in both Node.js and the browser. It supports a wide range of image manipulation tasks, including resizing, cropping, and color adjustments. Jimp is easier to use and more versatile than @expo/image-utils, but it may not be as performant for large-scale image processing tasks.

gm

GraphicsMagick (gm) is a Node.js wrapper for the GraphicsMagick and ImageMagick command-line tools. It provides a wide range of image processing capabilities, including resizing, cropping, and format conversion. While gm offers extensive functionality, it requires the installation of external dependencies, making it more complex to set up compared to @expo/image-utils.

README

👋 Welcome to
@expo/image-utils

A library for image processing functionality in Expo CLI.

It uses sharp for image processing if it's available through a global sharp-cli installation. Otherwise it uses jimp, a Node library with no native dependencies, and warns the user that they may want to install sharp-cli for faster image processing.

Advanced Configuration

This package can be configured using the following environment variables.

EXPO_IMAGE_UTILS_NO_SHARP

When truthy, this will force global sharp-cli resolution methods like isAvailableAsync() and findSharpInstanceAsync() to fail. Other processes can use this to fallback on Jimp for image modifications. By default this is falsy (undefined).

findSharpInstanceAsync() will throw an error if disabled because it shouldn't be invoked if isAvailableAsync() returns false.