[mule-aist:01294] Re: [Oriya-group] tables in utkalm.ttf
ntakahas at m17n.org
Wed Sep 8 11:52:44 IST 2004
Are there any progress or comments concerning utkalm.ttf mentioned
Kenichi Handa writes:
> Hi, my name is Kenichi Handa, a colleague of Dr. Takahashi.
> In article <1093417253.21067.203010049 at webmail.messagingengine.com>, "Rajesh Pradhan" <rajeshpradhan at speedymail.org> writes:
>>> I checked various combinations and found that it fails when
>>> KA(U+0B15), GA(U+0B17) or NNA(U+0B23) occupies the second position in
>>> a consonant cluster.
>>> I investigated the font and found that the "pres" GSUB feature has
>>> three lookup list indices, namely 9, 8 and 7 in this order. The three
>>> consonants mentioned above receive special treatment in "lookup 9",
>>> thus cannot be replaced with a proper ligature glyph by "lookup 8" or
>>> "lookup 7".
>>> I believe this is why our renderer fails. What is your intention for
>>> the special treatment in "lookup 9"? Does our renderer fail to
>>> understand the OpenType tables correctly?
>> Could you please give example of the oriya word you are trying to type?
>> I am not able to reproduce the problem using yudit. I shall look into
>> the "lookup 9" feature.
> I checked the source code of yudit and found that it handles
> lookups of types 1 (Single Substitution) and 4 (Ligature
> Substitution) only; it simply ignores lookups of the other
> types. And, the type of lookup 9 and 8 are both 6 (Chained
> Contextual Substitution). Thus, yudit displays this
> sequence correctly:
> U+0B38 U+0B4D U+0B15
> But our library handles a lookup of type 6.
> Here's the detailed flow. At first the above character
> sequence is converted to this glyph code sequence by cmap.
> 004A 0058 0029
> Next, "haln" feature (lookup 4) is applied to the sequence
> 004A 0058, and it is converted to 00C3. Thus now we have
> this sequence.
> 00C3 0029
> Next, we try "pres" feature (lookup 9 8 7 in this order).
> Lookup 9 (type 6) says that, while checking 0029, if the
> previous glyph is 00A3..00C4, try lookup 14. And lookup 14
> (type 1) says that 0029 should be converted to 00C5. Thus
> we have this sequence at last.
> 00C3 00C5
> On the other hand, lookup 7 (type 4) says that 00C3 0029
> sequence should be converted to 00E7, the correct final
> So, our question is why "pres" feature has lookups 9 8 7 in
> this order.
> Ken'ichi HANDA
> handa at m17n.org
ntakahas at m17n.org
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