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Re: [css3-images] How does image-orientation interact with EXIF data?

From: Tab Atkins Jr. <jackalmage@gmail.com>
Date: Tue, 7 Feb 2012 00:57:05 -0800
Message-ID: <CAAWBYDARWvGoNHAxSYTY31s708K7Mfg5zfPr8HONR3u6BXFumQ@mail.gmail.com>
To: Simon Fraser <smfr@me.com>
Cc: "www-style@w3.org list" <www-style@w3.org>
On Tue, Feb 7, 2012 at 12:24 AM, Simon Fraser <smfr@me.com> wrote:
> CSS3 Images talks about images being encoded sideways, and how this can be corrected for presentation via the image-orientation property:
> <http://dev.w3.org/csswg/css3-images/#image-orientation>
>
> However, it doesn't describe how this interacts with EXIF data in the image. My understanding is that an image may be tagged with EXIF data that indicates that the camera was in landscape orientation when the picture was taken, but this does not affect how the image is encoded.
>
> I think the spec needs to talk about how image-orientation and EXIF rotation data interact.

I don't think it's specified anywhere, but the web platform at this
point requires exif data to be ignored by default.  I'd be happy to
specify that somewhere in the draft.

David had previously suggested giving image-orientation some controls
based on exif - in particular, the ability to flip an image (so you
can achieve the "unnatural" orientations) and an 'auto' value that
just uses the exif orientation directly.  This has also been requested
by some Chrome devs.  I was planning to do this in Images 4, but if
it's important I can add it now.  I'll raise an issue.

~TJ
Received on Tuesday, 7 February 2012 09:01:37 GMT

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