On Fri, 7 Jun 2013, David Flanagan wrote:
>
> Allow direct read/write access to EXIF metadata via HTMLImageElement.
> The primary use case for read access is to enable web apps to
> trivially determine when, where, and how a photo was taken and also
> to determine authorship and copyright information for an image. The
> primary use case for write access might be for selectively stripping
> metadata. It would be nice to be able to protect user privacy with
> code as simple as |delete image.metadata.geolocation| for example.

On Fri, 14 Jun 2013, Mark Callow wrote:
>
> I think the primary use case is to make it trivial for JS to be able
> to orient an image according to its EXIF orientation when displaying
> it on the page. And this use case is huge. The vast majority of
> cameras today tag images with the camera's orientation when a
> picture is made. Today you have the following choices in order to
> have the image displayed correctly:
>
> 1. create a copy of the image rotated to a top-left orientation
> 2. manually apply a CSS style that rotates the image according to its
>    specific orientation
> 3. A hack using BinaryBlobs, extensive knowledge of the EXIF metadata
>    format and I don't know what else.

On Thu, 13 Jun 2013, Jonas Sicking wrote:
>
> Wouldn't an even better solution be to make browsers support that EXIF
> metadata and simply render the image correctly without any action from
> the page? At least assuming that the EXIF metadata for orientation is
> standardized and implemented consistently between cameras?

On Fri, 14 Jun 2013, Mark Callow wrote:
>
> It would, except that I think it would break a lot of existing web pages
> whose images have been rotated to a top-left orientation but whose EXIF
> metadata says something else. There was a period of years after EXIF
> appeared when many tools did not handle EXIF metadata, but, because it
> is packaged in a standard APP block of the JPG/JFIF format, may well
> have copied it unchanged into destination files after processing.
>
> Also images on sites using such a feature could appear with incorrect
> orientation in older browsers. The same could be said of rotating via
> JS/CSS, that reads EXIF from the HTMLImageElement, but at least the JS
> could issue a warning and recommend updating to a more recent browser.
>
> The EXIF orientation is standardized and handled consistently. However
> cameras without orientation sensors, i.e., older or cheaper cameras or
> cell phones, will set it to top left. But users of such cameras will
> notice the incorrect orientation when viewing on their computers and
> will rotate the images.