Re: Fonts across platforms....

From: Jukka K. Korpela (
Date: Wed Jun 03 2009 - 14:19:17 CDT

  • Next message: Ed Trager: "Re: Fonts across platforms...."

    Damon Anderson wrote:

    > I understand that the major barrier to
    > display of Unicode lies in fonts, but how does this relate to
    > platforms?

    Different operating systems and applications have different fonts shipped
    with them, and most people (excluding people on this list, of course) don’t
    acquire additional fonts.

    But fonts aren’t the only problem.

    > I have a document composed in OpenOffice on Windows using
    > the Verdana font and the Unikey unicode keyboard driver for
    > Vietnamese.

    I don’t know the Unikey driver, but its documentation suggests that it can
    produce characters both as precomposed and as decomposed. This might explain

    For example, the Vietnamese letter ệ can be represented in Unicode in
    several ways: as a precomposed single character or as a sequence of two or
    three characters, building the character up from constituents (the base
    letter “e” and two diacritic marks). These representations are distinct as
    Unicode data, though they represent the same character (when using a more
    abstract concept of character). Their renderings are in theory supposed to
    be identical but in practice they are very often differences.

    > I open the same document in my OpenOffice on Linux
    > (Kubuntu) after installing the Verdana font and many of diacritical
    > marks are now on the wrong letters or shifted to the right one
    > character space.

    One computer’s Verdana need not be identical with another computer’s
    Verdana. But the symptoms suggest that the problem might be in the
    representation variation.

    For example, suppose that your writing tool produces the letter ệ internally
    as a three-character sequence: the base letter and two combining diacritics.
    Some program might then internally convert that into a precomposed single
    character and render it using the selected font. Another program might print
    the letter “e”, then position the circumflex and the dot below (as taken
    from the font) somehow, and they might do a good job here but also a lousy
    job. The most primitive algorithms just overprint the base letter using a
    glyph for the diacritic in a fixed position. (This means, of course, that if
    ê produced that way looks tolerable, Ê won’t, and vice versa.)

    > If even the font displays aren't consistent across
    > platforms where in lies the problem and how can I distribute
    > consistently displayed documents?

    Perhaps you can use embedded fonts. The possibilities and methods for this
    depend on the software and on fonts (not all fonts allow embedding).

    But for Vietnamese, I would expect that reasonably good consistence can be
    achieved if you use a commonly available (though perhaps typographically
    suboptimal) font like Verdana, Arial, or Times New Roman and make sure that
    your Unicode data uses precomposed characters.

    As a rough estimate, you might use the font list at
    (the character U+1EC7 is of course just a more or less arbitrary pick, but I
    would expect a font to support all of Vietnamese if it supports this
    particular character, which is used in Vietnamese only). Then you would need
    to find out which of the suitable fonts are by default available on
    platforms that matter in your case.


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