[Webkit-unassigned] [Bug 210021] EXIF orientation info in PNGs isn't used for image-orientation: from-image

[bugzilla-daemon at webkit.org]

https://bugs.webkit.org/show_bug.cgi?id=210021

--- Comment #3 from Simon Fraser (smfr) <simon.fraser at apple.com> ---
This seems to be a quirk of the image.

The image has these chunks:
        IHDR
        PLTE
        IDAT
        eXIf
        IEND
libpng does not recognize the ‘eXIf’ chunk if it’s after the image data (IDAT).
The spec states: “The eXIf chunk may appear anywhere between the IHDR and IEND chunks except between IDAT chunks.”
So in theory it’s allowed, but libpng does not support this.
If the PNG is modified (moved eXIf before IDAT) it displays as expected (90º rotated).
FireFox, Chrome, GraphicConverter don’t handle this either.

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