Re: Prepending vowel exception in Lontara/Buginese script ?

2011/7/24 <vanisaac_at_boil.afraid.org>:
> From: verdy_p <verdy_p_at_wanadoo.fr>
>>
>> If I look in the Unicode 6.0 charts for the Buginese script, I see that
>> vowel /e/ (U+1A19) is prepended visually on the left of the base consonnant
>> to which it applies. This should mean that the vowel has to be encoded
>> ilogically in texts AFTER the base consonnant to which it applies.
>
> It actually IS encoded logically, just not visually. Logically, the E comes after after the consonant sound. That's the reality that Unicode reflects. The fact that the script prepends this vowel mark before the consonant doesn't change that it logically comes after the consonant.
>
>> However, I have tested all fonts available on the web for this script, and
>> none of them contain the necessary OpenType substitution feature needed to
>> make the logical-to-visual reordering.
>> [...]
>> What can be done? Should the fonts be corrected to include the OpenType
>> feature,
>
> Yes.

OK.

Regarding browsers, Chrome at least is correct when editing text : it
uses the correct grapheme cluster boundaries when selecting or editing
text, so that the diacritic letter is associated with the previous
base character (including if this is another character than a Lontara
base consonnant,or a space, for example an ASCII pipe used for the
syntax of MediaWiki table cells).

For now, I have corrected the English and French pages in Wikipedia
describing the "Lontara script", including the note about the
necessary logical-to-visual feature for fonts, and the expected
display. I have also modified the displayed char maps for the
U+1A00..U+1A1F range, and text samples so that the diacritic vowel E
is effectively encoded AFTER the base consonnant (or AFTER the dotted
circle symbol when showing the character in isolation) that it is
supposed to modify. I have also posted a comment in the associated
discussion page about this.

I have detected the problem when I was contacted personnally to make a
test page for the script.

So I'll contact the authors of the free fonts available on the web for
the Lontara script to correct these fonts. Two free fonts, supposed to
be Unicode-compatible are bogous :

- "Saweri" : it maps ONLY the characters of the Lontara block, plus
the regular SPACE, but this is a TrueType-only font, it has NO
OpenType feature included for the prepended vowel. Two versions of the
fonts (each package containing normal and bold styles) are available
fro mthe same page. The first version uses a narrow style with basic
straight segments and a very elementary design (a few strokes are
incorrect, and the dots below the base line of some base consonnants
are too low, causing a confusion with the dot below used by the second
diacritic vowel). The second one (labelled "V2" in the pack, but the
font internally uses the same font name and the same version number
1.0) is nearer from the style used in the Unicode chart, with a few
strokes more rounded, and better placement of dots in the basic
consonnants.

- "MPH 2B Damase" (it is an OpenType-enabled font, but with correct
glyph design, but it forgot to include the necessary feature for
Lontara).

>>  or should Unicode be modified to inclide the "prepended vowel"
>> exception
>
> No.
>
>> also for Buginese, and so the default grapheme boundaries modified
>> as well, and the Unicode 6.0 chart modified too for U+1A19 ?
>
> No.

Thanks a lot for the clear response.

Are there other free fonts available for this script ? Notably one
that includes at least the necessay Indic feature ?

-- Philippe.
Received on Sat Jul 23 2011 - 20:44:37 CDT