Re: Unicode TTF question

From: Peter Kirk (
Date: Wed Aug 24 2005 - 18:19:56 CDT

  • Next message: Adam Twardoch: "Re: Unicode TTF question"

    On 24/08/2005 23:27, Philippe Verdy wrote:

    > ...
    > Unfortunately, browsers are not prepared for that: even MSIE will not
    > allow you to select font preferences for new scripts, because it seems
    > to use an hardwired list of scripts, instead of consulting a registry
    > of font capabilities, and the capabilities of the OTLS shaping engine
    > (if a script requires to activate some OT features within some complex
    > sequence before or after reordering...)

    MSIE (on Windows XP) seems to have a specific problem with web pages
    using the non-core parts of a script. For example, when viewing a web
    page including Greek Extended characters and/or Hebrew accents (see
    for an example - but the original problem on this page with Greek
    Extended has been fixed by specifying the font Tahoma), where the
    default font for the page (in the case of this blog posting provided by
    a template) does not support those characters, MSIE apparently
    substitutes the default font with a font which is registered as
    supporting "Greek" or "Hebrew" but does not in fact support the extended
    characters or accents. So the unsupported characters end up replaced by
    empty boxes.

    Mozilla Firefox does somewhat better, as instead of giving empty boxes
    it finds a suitable glyph from any available font, which is usually
    legible even if it doesn't match the rest of the word properly.

    This is quite a serious problem because it comes close to making certain
    characters, e.g. Greek Extended characters and Hebrew accents, unusable
    on the Internet. Browsers need somehow to ensure that their font
    substitution mechanisms actually find a glyph for each character. One
    way to do this would be to choose as substitutes only fonts which are
    guaranteed to cover the whole of a particular Unicode block. If there is
    "a registry of font capabilities", it must be accurate, and not allow
    claims to support the whole of Hebrew when certain characters are not
    supported at all - nor interpret a claim to support Greek as applicable
    also to the Greek Extended range.

    Peter Kirk (personal) (work)
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