Rendering of sequences containing double diacritic (was Re: Bantu click letters)

From: Bob_Hallissy@sil.org
Date: Fri Jun 11 2004 - 09:40:21 CDT

  • Next message: Anto'nio Martins-Tuva'lkin: "Shavian (was: "Re: Bantu click letters")"

    On 11/06/2004 14:39:48 James Kass wrote:

    >-------------- Original message from "Anto'nio Martins-Tuva'lkin" :
    >--------------
    >> On 2004.06.10, 17:11, I wrote:
    >>
    >> > U+0251 U+0361 U+0302 U+028A as given by BabelMap+Code2000 (see
    >> > attached) is not productively different from U+0251
    >> > U+0302 U+0361 U+028A (see attached)...
    >>
    >> Now attached. (Both GIFs are identical, byte by byte, though I swear
    >> I made them separately: click the characters in BabelMap, PrtScr,
    >> paste into PhotoShop, crop, resample, save!)
    >
    >You're getting default positioning only, it looks like your system
    >doesn't support OpenType combining diacritic positioning for Latin.
    >
    >Even with OpenType experimental support here, my display looks like
    >the GIF you sent. I'll try fixing this,

    Um, good luck. I am not sure it is possible to correctly position
    double-diacritics with OpenType logic. Specifically, the vertical position
    of the double-diacritic must be adjusted so that it is above the *taller*
    of the preceding and following combining sequence. AFAIK, such logic isn't
    feasible in OpenType.

    >Fonts and rendering systems probably aren't ready for this kind of
    >combination yet.

    SIL Graphite handles it, but then we don't [yet] have wide-spread
    availability of Graphite-capable applications.

    >> > U+0251 U+0361 U+0302 U+028A as given by BabelMap+Code2000 (see
    >> > attached) is not productively different from U+0251
    >> > U+0302 U+0361 U+028A (see attached)...
    >
    >Following the "inside-out" rule, the first sequence should render
    >correctly, the second sequence should not.

    Not sure what you are saying here or what you mean by the inside-out rule.
    The two sequences are canonically equivalent and should look identical.

    Bob



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