[XeTeX] misplaced combining diacritical marks 2

[Alexander Schultheiß]

Hello Jonathan,

As for this morning I wasn't able to connect to sil.org (ping gives
Destination Host Unreachable) to download the font you suggested but I
will definitely do that today.

> I have not attempted to follow this thread closely, but I will just comment that xetex DOES normally use OpenType mark-positioning features as defined in GPOS tables. It does not "fake" anything regarding this, although it's possible that additional macro packages (such as xunicode) may attempt to "fake" characters or combinations that are not actually supported by the font in use -- or may interfere with the native operation of the font, if they try to redefine combining marks, etc.

I have disabled xunicode with no results. If what you say is true and
xelatex does make use of the GPOS table then why is it unable to
assemble an a+macron if the pre-composed glyph at unicode code point
0101 gets deleted? Also, if a pre-composed glyph is found in the font
and another diacritic is added and the pre-composed glyph has no
anchor then xelatex seems to use the comb. diacritical marks with
their fixed negativ widh and their fixed height and simply adds the
diacritic, at least in Junicode; though it could use the anchor
points. I've attached a pdf output of you code using Junicode and you
can see the described behavior e.g. with the M+macron in the first
line. Or is this a weird behavior from my machine? I have a fresh
install of texlive2009 with all packages on a slackware 12.2 GNU/Linux
box. I'm using fontforge to make my fonts and

> Example to show the use of mark positioning using the Charis SIL font, which has extensive support for diacritics, handled using anchor points on the base and diacritic glyphs:

I'll look into this as soon as sil.org is reachable for me.


Alex
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