Re: Shaping Hangul text with U+115F and/or U+1160

The "Default ignorable" property has nothing to do with rendering or
being zero-width, it's just a matter of collation (comparing strings
for similarity, for plain-text searches, or sorting them), it does not
necesarily mean that the character is zero-width (that's a rendering
property).

Characters that are "default ignorable" may still have an effect on
cluster boundaries used when editing texts, if you count manually the
number of zero-width characters (by pressng the left or right arrow
fnction keys.) As long as the rendering is correct, editors may allow
you to place insertion points between them.

U+115F is the choseong filler (used when there's no leading consonnent
to place before a medial vowel), U+1160 is the jungseong filler (used
to replace a missing medial or final vowel).

You're right when saying that there should be two clusters in
<U+115F, U+1161>, <U+112B, U+1160>
- The first one is a isolated vowel A, it should become spacing but
U+115F is just used as an invisible holder for the vowel,
- The second one is an isolated consonnant KAPYEOUNPIEUP, and the
U+1160 filler will remain invisible except that it iis used here so
that it explicitly terminates the cluster if it was followed by a
leading consonnant or dirctly by a "defective" vovel.

But the U+115F and U+1160 Hangul fillfers remain default ignorable in
collation. And there's no bug about this.

2013/3/18 Konstantin Ritt <ritt.ks_at_gmail.com>:
> 2013/3/18 Konstantin Ritt <ritt.ks_at_gmail.com>:
>> The user reports Korean text rendering issue with any modern Hangul
>> font when U+115F and U+1160 are handled like default_ignorable code
>> points.
>> [quote]With input string "U+115F U+1161 U+112B U+1160", we get three
>> zero-width glyphs instead of two; this is wrong.[/quote]
>> I did check some Hangul font and found that either U+115F or U+1160
>> zero-advances, not both. When handling them like default ignorable,
>> the rendered text seems to lack some advancing.
>> Since I know nothing about Korean typography, I'd like to ask here:
>> what is the reason for U+115F and U+1160 to be default ignorables and
>> shouldn't that be revised?
Received on Mon Mar 18 2013 - 02:36:35 CDT