[whatwg] Add EXIF metadata support in Canvas.toBlob?

Mark Callow callow.mark at artspark.co.jp
Thu Jun 13 22:22:35 PDT 2013

On 2013/06/14 12:45, 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?
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.



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