Auto rotation without any other modification

[digilist]

I would be great if there is an option/endpoint to fix the orientation of an image based on the EXIF data without modifying the image in any other way. The rotate endpoint works only if a rotate parameter is given and a 0-value does not work.

Not sure, if I am missing something and this works already, but I didn't find it. I did not explore workarounds such as doing a resize that keeps the current size of the image (with auto-rotation), but this does not feel right anyway.

[h2non]

By default, images are automatically rotated based on its EXIF metadata, if available and the image is not properly oriented according to it.

You can disable this behavior by passing the URL query param norotation=true, and then explicitly pass the rotation behavior via rotate=degrees if needed.

[digilist]

Thanks for your answer. But what I mean is that the image is only rotated without any other modification, so I do not want to resize etc. and only fix the orientation. Is there a way?

So I mean something like an /autorotate endpoint that fixes the orientation and returns a new image. If the orientation is already correct, it returns the original image.

[h2non]

There is an endpoint specifically for that:
https://github.com/h2non/imaginary#get--post-rotate

[digilist]

But with that endpoint the rotate parameter must be provided to define the angle of the rotation. A value of 0 does not work and results in an error that the parameter is required.

[h2non]

The autorotate endpoint might be a good option and easy to implement.

In the meanwhile, you might try getting the image info, and based on the returned orientation field value, make another call to rotate the image, if needed:
https://github.com/h2non/imaginary#get--post-info

Alternatively, you can try using the /convert endpoint with no actual image transformation and passing the same image format in the type query param:
https://github.com/h2non/imaginary#get--post-convert

[h2non]

The /autorate endpoint feature is now available in imaginary v1.2.3.

More details here: https://github.com/h2non/imaginary#get--post-autorotate

[digilist]

Great, thank you :) I gave it a try and it is able to fix a few rotations, but unfortunately not all of them.

I used the images in repository for testing: https://github.com/recurser/exif-orientation-examples
The cases 2, 4, 5 and 7 are not rotated correctly.

I saw that you implemented the autoration using the AutoRotate method from libvips and it looks like libvips does not support all orientations yet, but it will with libvips 8.10 which should come out soon (libvips/libvips#1766)

So I think it's worth waiting for the new libvips version and I just wanted to post this for your information.

[h2non]

Cool, thanks! We will sure upgrade to libvips 8.10 as soon as the stable version is available.

[digilist]

Thanks for the update! I just tested it again and it works like a charm.