Autorotate gallery images

[reagle]

sigal seems smart enough to orient portrait images when it is within its own HTML framing. However, the actual jpgs (thumbnail and gallery images) are not rotated. I'd prefer the actual images be rotated so that if I want to use the image or thumbnail elsewhere on my website, it's in the correct orientation.

[saimn]

The rotation is done by pilkit:
https://github.com/saimn/sigal/blob/master/sigal/image.py#L77
https://github.com/matthewwithanm/pilkit/blob/master/pilkit/processors/base.py#L113

But there may be an issue with the copy_exif_data setting which copy the original exif (with the unmodified orientation tag). To confirm this, could you try with copy_exif_data = False ?

[reagle]

Related to firefox not rotating the image: https://bugzilla.mozilla.org/show_bug.cgi?id=298619

[reagle]

Okay, so my understanding is that you are rotating the images, but not removing the orientation exif; hence exif-compliant software like Chrome rotates it again. Why can't we remove the tag ourselves?

https://github.com/saimn/sigal/blob/master/sigal/image.py#L73

 # Preserve EXIF data
    if settings['copy_exif_data'] and _has_exif_tags(img):
        if options is not None:
            options = deepcopy(options)
        else:
            options = {}
        options['exif'] = img.info['exif']

    # Rotate the img, and catch IOError when PIL fails to read EXIF
    try:
        img = Transpose().process(img)
        del options['exif']['Orientation']  # something like this

    except (IOError, IndexError):
        pass

[saimn]

Okay, so my understanding is that you are rotating the images, but not removing the orientation exif; hence exif-compliant software like Chrome rotates it again

Yes. The problem is that it is currently not possible to save the modified exif with Pillow. (There may be a possibility, hacking with the internal stuff of Pillow, but I did not managed to get it work yet)
A feature request has been filled : python-pillow/Pillow#520
Thus, the only solution I see for now is to add a new setting to disable the autorotation, and let the user choose between autorotation and exif copy (the 'copy_exif_data' setting).

[reagle]

Confirmed copy_exif_data = False does not have this problem in Chrome.

[reagle]

@saimn I'm not sure how long (if at all) the python-pillow/Pillow#520 will take to resolve, would you be opposed to a dependency on gexiv2. (gexiv2 is the update to pyexiv2, which is discussed in "How to use PIL to resize and apply rotation EXIF information to the file?".)

btw: jhead -norot does this nicely.

[saimn]

I was using pyexiv2 at the beginning (it was optional). But the installation of pyexiv2/gexiv2 is a problem, it is not available on pypi, so I don't want to add a dependency on this. And I don't know if it is easily installable on all platforms ?

[reagle]

That's helpful, any news on an upstream fix from PIL?

[reagle]

Just looked about, don't see any evidence of the bug python-pillow/Pillow#520 receiving any attention nor of gexiv2 (as an alternative) appearing in pypi. However, there are a fair amount of exif tools in pypi such as exifyay. There's also img_rotate "Rotates PIL Image instances after EXIF-tagged image orientation" (however, it loses exif data as well). But maybe there's something there that could help.

[saimn]

img_rotate doesn't modify the EXIF data, it just rotate the images and doesn't the EXIF data. exifyay is more interesting but, even if it is available on pypi, you must compile it manually with cmake.

[reagle]

Any news on this front? Sadly, I don't see any change.

[saimn]

Hi Joseph,
Nope, no news. However I'm working on a plugin system for sigal, so one option could be to make a plugin for exifyay. This way it would not add a strong dependency to sigal, but it would be a good solution for people who need this feature.

[reagle]

I'm wondering if there's been any movement on this one?