[ft] Ideographic Variation Sequence (IVS)

[Jeroen Hoek]

Hello,

I hope I am asking this at the right project, please excuse me if I am
mistaken. Mailinglist archives and documentation searches yielded no results.

In 2006 the Unicode Consortium introduced the concept of Ideographic Variation
Sequences (IVS) and the Ideographic Variation Database (IVD). This system
allows font designers to include variant glyphs for characters encoded at a
single codepoint. This is needed for the languages used in CJKV cultures
(China, Taiwan, the Koreas, Japan, and historically Vietnam), where regional
names and historical usage sometimes necessitates a less common variant glyph.
An example is given in UTS #37, appendix B.1:

http://www.unicode.org/reports/tr37/#w3ac17b5b1

The system appears fairly simple; any character can be followed by a variation
selector, a Unicode character from the range U+E0100 to U+E01EF. If the font
used supports IVS and a glyph corresponding to that variation selector is
available, that glyph is used instead of the default glyph for that codepoint.

I am not very familiar with the technical details, but I believe those variant
glyphs are not directly encoded, but exclusively accessible through the
combination of a character followed by a variation selector, using cmaps.

My question is: is this something Freetype should eventually support? And if
so, is this on the radar for the Freetype project?

Kind regards,

Jeroen Hoek