XP Mail Archive: XP> Request for discussion of the interacti

XP> Request for discussion of the interactions of EXIF orientation ma rkers and a CSS image orientation property

From: BIGELOW,JIM (HP-Boise,ex1) (jim.bigelow@hp.com)
Date: Mon Jan 06 2003 - 21:01:28 EST

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    Hello,

    The XHTML-Print specification states how an enhanced layout printer should
    handle EXIF markers in JPEG images
    (http://www.pwg.org/xhtml-print/HTML-Version/XHTML-Print.html#a_jpeg.3).

       A JPEG decoder for an XHTML-Print implementation which
       supports the Enhanced Layout Extension shall decode the
       TIFF IFDs embedded in the EXIF APP1 and APP2 markers, as
       described in Section 2.6.4 of [JEIDA]. The following IFDs
       shall be fully supported (i.e. they shall not be ignored).
       Tag Name: Image Orientation
       Field Name: Orientation
       Description: Sets image orientation in 90-degree increments,
                    and enables transposition.

    This requirement was discussed at the April and June 2002 meetings. See
    http://www.pwg.org/xhtml-print/minutes/Minutes-June-24-2002.html and
    http://www.pwg.org/xhtml-print/minutes/Minutes-April-17-2002.txt The June
    meeting decide to make the processing of EXIF markers optional. Therefore,
    text above should be changed to say "may decode" from "shall decode" and
    "shall be fully supported (i.e., shall not be ignored)." becomes "may be
    supported."

       A JPEG decoder for an XHTML-Print implementation which
       supports the Enhanced Layout Extension may decode the
       TIFF IFDs embedded in the EXIF APP1 and APP2 markers, as
       described in Section 2.6.4 of [JEIDA]. The following IFDs
       may be supported.
       Tag Name: Image Orientation
       Field Name: Orientation
       Description: Sets image orientation in 90-degree increments,
                    and enables transposition.

    Melinda Grant posed a question in the June meeting about optional support
    for EXIF markers and a future CSS property that specified image orientation
    and how the two would interact. The CSS working group of the W3C is
    currently considering an image orientation property, so this concern could
    come up in one to two years.

    I propose that a CSS property, if present, take precedence over the image's
    EXIF orientation markers.

    Comments?

    Jim Bigelow,
    Editor: XHTML-Print & CSS Print Profile
    IEEE, Printer Working Group
    http://www.pwg.org/xhtml-print
    Hewlett-Packard
    208-396-2068
    jim.bigelow@hp.com

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