From: James Kass (thunder-bird@earthlink.net)
Date: Wed Jan 30 2008 - 03:18:10 CST
John Knightley wrote,
> thank-you, GPOS certainly manages to centre the dots correctly-at
> least in some applications.
>
> U+0332 combining low line however needs to be half or full width
> depending upon the width of the character it is combined with.
>
> It would appear from comparng that Code2000 and SIL Doulos use some
> other mechanism to produce stacking.
Code2000 uses OpenType GPOS (glyph positioning) tables to stack diacritics
and to reasonably place diacritics in relation to their base characters. The
SIL Doulos font most probably uses the same method.
> For some reason - the stacking feature, by mark to ligature does not
> seem to work. This however maybe due to other factors.
Can you post a graphic example of the notation you desire? It
is said that a picture is worth a thousand words, and this might
help us understand the desired behaviour.
The fullwidth presentation forms of Latin characters (and western digits)
may present an interesting problem. I'd have to check, but I'm pretty
sure that I've made no allowances for any of them using GPOS and
combining marks. I'm also not sure if a rendering engine will attempt
to shape characters from that range, but it would make for an interesting
test.
(Even the ASCII digits -- I had not considered that anyone would need
to put combining marks with them and so did not make any effort to
assign what are called "anchor points" to them.)
Best regards,
James Kass
This archive was generated by hypermail 2.1.5 : Wed Jan 30 2008 - 03:21:32 CST