Re: Open public review items...

From: William Overington (
Date: Thu May 22 2003 - 07:06:09 EDT

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    Rick McGowan wrote, quoting the following.


    5 Object Replacement Char
    Whether to treat U+FFFC Object Replacement Character and the
    Interlinear Annotation Characters as "default ignorable" or to have a
    default visible representation. See the accompanying document for details.

    end quote

    I studied this some time ago, yet feeling that I had no strong views either
    way, though perhaps tending to think that on balance if the information is
    there perhaps an end user should, by default, have his or her attention
    drawn to the fact, I decided not to send in a representation.

    However, I wonder if I may make mention of a matter which has arisen in my
    research which might possibly be of relevance in the general context of
    U+FFFC and, even if not directly relevant, may perhaps be of interest

    As some readers may know I have placed on the web a note about applying the
    U+FFFC character in digital interactive television systems.

    Here are some notes which I have prepared as part of an as yet unpublished
    document about an access level multimedia authoring system for use upon the
    DVB-MHP (Digital Video Broadcasting - Multimedia Home Platform) system.

    (Please note that the following text is part of a longer document where
    various Private Use Area characters are being introduced to allow a
    programmed learning type presentation system (a Java program which would be
    broadcast on a digital television channel) to be customized as to the
    information to be displayed on the television screen by using Unicode text
    files which have been prepared using a widely available program such as
    Microsoft WordPad. This is so that people who are subject specialists in,
    say, history or geography, can author learning material for a free to the
    end user distance education interactive DVB-MHP channel which uses the
    enhanced broadcast profile, which interactive content would need no return
    link to the central broadcasting computer.)

    A separate, though related, issue, is for a program feature involving
    illustrations, which a programmer may or may not choose to implement, which
    involves the provision of four characters for use in relation to U+FFFC, the
    Object Replacement Character.
    There is a suggestion about the possibility of using U+FFFC on the DVB-MHP
    platform in the following document, which is entitled as follows.
    Using the U+FFFC character on the DVB-MHP platform.
    When using a program such as WordPad to prepare a file of multimedia content
    as suggested in this present document, a problem arises over including a
    U+FFFC character in the document.  This is because WordPad has its own
    facilities for including pictures and direct including of U+FFFC into a
    WordPad document using Alt 65532 is not possible.
    This is entirely reasonable of the WordPad program, yet does prevent use of
    WordPad for placing a U+FFFC character into a file for this present
    multimedia authoring purpose.
    In view of this, I decided to define U+EBCF to be OBJECT REPLACEMENT
    CHARACTER SYNONYM and ask that anyone programming picture handling
    facilities into a multimedia system based on the contents of this present
    document please consider making U+EBCF and U+FFFC have identical meanings.
    That will mean that a content author using WordPad on a PC can produce
    usable content files directly, whereas someone using SC UniPad or some
    package designed specifically for multimedia authoring using this system,
    can use U+FFFC directly.
    Upon considering the matter further I decided to add three more Object
    Replacement Characters, the three new characters having information about
    alignment of the picture included in their definitions.
    The list is thus as follows.
    These are decimal 60364 through to 60367 respectively.
    I have designed a set of glyphs for these characters based around a thick
    circle.  The first three have a vertical line upon the left, the centre and
    the right of the thick circle respectively.  The fourth has no vertical
    The glyphs for U+EBCC through to U+EBCF are for use at authoring time on a
    PC using WordPad.  It is not intended that these glyphs would be displayed
    upon the screen of the interactive television set.
    Certainly from a Unicode Standard view the above are simply Private Use Area
    characters.  However, as this matter has arisen I wonder if perhaps users of
    the Unicode Standard might like to know of this matter as it has arisen as a
    result of experiencing a problem when trying to apply U+FFFC in a particular
    William Overington
    22 May 2003

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