Dedotted I and dotlessi

[Bobby de Vos]

On 2020-08-17 8:58 a.m., Khaled Hosny via Unicode wrote:

>> On Aug 17, 2020, at 10:37 AM, Richard Wordingham via Unicode <unicode at unicode.org> wrote:
>>
>>  Is the
>> recommendation applicable to Indic scripts, where glyph stream to
>> character stream conversion may be as complicated as the
>> reverse direction and there is a natural tendency for distinctions to
>> be lost.  (In Devanagari, the distinction between mandated and
>> fallback half-forms is one example.)
> Same workflows can’t handle one to many substitution, or reordering, so when I’m doing fonts that need these I usually just give up on the “unique glyph per code point” requirement. I also forget about it when making Arabic fonts, because extracting Arabic text reliably from PDFs generated with such workflows is a lost cause already.

A particular workflow might be enhanced to handle, for example, U+093F
DEVANAGARI VOWEL SIGN I where the glyph for this character is re-ordered
compared to the codepoints. I don't see how a workflow would be able to
handle [1] where in Kannada script, codepoints are re-ordered to handle
changing conventions in encoding. That is, the codepoints are re-ordered
before mapping to glyphs, so two different sequences of codepoints will
produce the same glyph stream, IIUC.

[1] https://github.com/harfbuzz/harfbuzz/issues/435#issuecomment-335560167

Regards, Bobby

-- 
Bobby de Vos
/bobby_devos at sil.org/
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