johansatge / Jpeg Autorotate

A node module to rotate JPEG images based on EXIF orientation.

• What does it do
• Installation
• Usage
  • Options
  • CLI
  • Node module
    • Sample usage
    • Error handling
• Troubleshooting
  • Thumbnail too large
• Changelog
• License
• Contributing
• Credits

What does it do

This module applies the right orientation to a JPEG image, based on its EXIF tag. More precisely, it:

• Rotates the pixels
• Rotates the thumbnail, if there is one
• Writes 1 in the Orientation EXIF tag (this is the default orientation)
• Updates the PixelXDimension and PixelYDimension EXIF values
• Does not alter the other EXIF tags

It may be useful, if:

• You need to compress your image with a tool that strips EXIF data without rotating the pixels (like the great ImageOptim)
• You need to upload the image, but the destination application does not support EXIF orientation (like WordPress)
• You just want to get rid of the orientation tag, while leaving the other tags intact

More information about EXIF:

• EXIF Orientation Handling Is a Ghetto
• Standard EXIF Tags

Installation

This module needs Node >=10.

Install with npm:

$ npm install jpeg-autorotate --global
# --global isn't required if you plan to use the node module

Usage

Options

CLI

Rotate a single image:

$ jpeg-autorotate /Users/johan/IMG_1234.jpg

Rotate a set of images:

$ jpeg-autorotate /Users/johan/images/IMG_*.jpg

Glob support:

$ jpeg-autorotate "/Users/johan/images/IMG_*.{jpg,jpeg,JPG,JPEG}"

Passing options:

$ jpeg-autorotate /Users/johan/IMG_1234.jpg --quality=85 --jpegjsMaxResolutionInMP=1234

Node module

The Node module will load the image, apply the rotation, and return the binary data as a Buffer, allowing you to:

• Save it on disk
• Load it in an image processing module (like jimp, lwip, gm...)
• ...

Sample usage

const jo = require('jpeg-autorotate')
const options = {
  quality: 8,
  jpegjsMaxResolutionInMP: 1234,
}
const path = '/Users/johan/IMG_1234.jpg' // You can use a Buffer too

//
// With a callback:
//
jo.rotate(path, options, (error, buffer, orientation, dimensions, quality) => {
  if (error) {
    console.log('An error occurred when rotating the file: ' + error.message)
    return
  }
  console.log(`Orientation was ${orientation}`)
  console.log(`Dimensions after rotation: ${dimensions.width}x${dimensions.height}`)
  console.log(`Quality: ${quality}`)
  // ...Do whatever you need with the resulting buffer...
})

//
// With a Promise:
//
jo.rotate(path, options)
  .then(({buffer, orientation, dimensions, quality}) => {
    console.log(`Orientation was ${orientation}`)
    console.log(`Dimensions after rotation: ${dimensions.width}x${dimensions.height}`)
    console.log(`Quality: ${quality}`)
    // ...Do whatever you need with the resulting buffer...
  })
  .catch((error) => {
    console.log('An error occurred when rotating the file: ' + error.message)
  })

Error handling

The error object returned by the module contains a readable message, but also a code for better error handling. Available codes are the following:

const jo = require('jpeg-autorotate')

jo.errors.read_file // File could not be opened
jo.errors.read_exif // EXIF data could not be read
jo.errors.no_orientation // No orientation tag was found
jo.errors.unknown_orientation // The orientation tag is unknown
jo.errors.correct_orientation // The image orientation is already correct
jo.errors.rotate_file // An error occurred when rotating the image

Example:

const jo = require('jpeg-autorotate')
jo.rotate('/image.jpg')
  .catch((error) => {
    if (error.code === jo.errors.correct_orientation) {
      console.log('The orientation of this image is already correct!')
    }
  })

Troubleshooting

Thumbnail too large

The piexifjs module has a 64kb limit when reading thumbnails. If you get the Given thumbnail is too large error, you can try to remove the thumbnail from the image before rotating it:

import piexif from 'piexifjs'

function deleteThumbnailFromExif(imageBuffer) {
  const imageString = imageBuffer.toString('binary')
  const exifObj = piexif.load(imageString)
  delete exifObj['thumbnail']
  delete exifObj['1st']
  const exifBytes = piexif.dump(exifObj)
  return Buffer.from(piexif.insert(exifBytes, imageString), 'binary')
}

Changelog

This project uses semver.

License

This project is released under the MIT License.

Contributing

Bug reports and feature requests are welcome! More details in the contribution guidelines.

Credits

• piexifjs
• jpeg-js
• exif-orientation-examples
• colors
• yargs
• FontAwesome
• Chai
• Mocha
• eslint
• glob
• prettier