jpeg-autorotate

Rotates JPEG images based on EXIF orientation.

---

• What does it do
• Installation
• Usage
  • CLI
  • Node module
    • Sample usage
    • Error handling
  • Options
• Changelog
• License
• Credits

What does it do

This tool 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 orientation: EXIF Orientation Handling Is a Ghetto

Installation

Install with npm:

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

Usage

CLI

# Rotates a single image
$ jpeg-autorotate /Users/johan/IMG_1234.jpg
# Rotates a set of images
$ jpeg-autorotate /Users/johan/images/IMG_*.jpg

Node module

The tool is available as a Node module. It 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

var jpegautorotate = require('jpeg-autorotate');
var options = {quality: 85};
jpegautorotate.rotate('/Users/johan/IMG_1234.jpg', options, function(error, buffer, orientation)
{
    if (error)
    {
        console.log('An error occurred when rotating the file: ' + error.message);
        return;
    }
    console.log('Orientation was: ' + orientation);
    // ...
    // Do whatever you need with the buffer
    // ...
});

Error handling

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

var 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

Sample usage:

var jo = require('jpeg-autorotate');
jo.rotate('/image.jpg', function(error, buffer, orientation)
{
    if (error && error.code === jo.errors.correct_orientation)
    {
        console.log('The orientation of this image is already correct!');
    }
});

Options

The following options are available.

Option	Context	Default value	Description
quality	CLI, module	100	Quality of the JPEG - Uncompressed by default, so the resulting image may be bigger than the original one
jobs	CLI	10	Max number of concurrent processes, when loading several images

To use options with the CLI:

$ jpeg-autorotate /image.jpg --jobs=100 --quality=85

Changelog

This project uses semver.

Version	Date	Notes
1.0.2	2016-03-21	Adds missing options in CLI help
1.0.1	2016-03-21	Fixes NPM publishing fail ^_^
1.0.0	2016-03-21	Initial version

License

This project is released under the MIT License.

Credits

• piexifjs
• lwip
• colors
• yargs
• async
• FontAwesome