On Wed, Jul 7, 2010 at 2:26 AM, Vincent Hennebert <vhenneb...@gmail.com>wrote:

> It must be seen whether advanced typography is needed to properly
> typeset Korean (for example, glyph shaping like in Arabic). Advanced
> typographic tables are not used by FOP’s layout engine at the moment.
> That may make the issue much more complicated.
Advanced typography support from fonts (e.g., GSUB/GPOS tables) is NOT
required to support common encoding of Korean, which in almost all cases
employs umgeol (syllable) instead of jamo (consonant/vowel) coding. In
Unicode, umgeol characters are encoded in the BMP range 0xAC00 to 0xD7AF,
while combining jamo are at 0x1100 to 0x11FF. Formatting the former requires
the same level of typographic support as CJK Han characters, which amounts
to little more than allowing line breaks at any character boundary (unless
one is doing Japanese with JISX4051 rules). In contrast, formatting the
combining jamo encoding of Korean requires a large ligature table or
equivalent logic (to map sequences of combining jam to corresponding

As a historical aside, Unicode originally supported only combining jamo,
which would indeed have forced advanced character to glyph mapping support;
however, Microsoft Korea successfully pushed through the only non-backward
compatible change to Unicode to bring in the entire block of 11,183 umgeol
syllables. In retrospect, adding he umgeol was the right move.


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