[XeTeX] Font question

[Jonathan Kew]

On 15 May 2005, at 10:09 pm, Jonas Wellendorf wrote:

> Ok. Now I can see what the hooked o looks like in my editor using 
> Hoefler as document font in my editor and typing o followed by 
> alt-0328 on the Hex keyboard.
>
> But the resulting pdf-document is still not as I would expect. Instead 
> of the hooked o I get an o followed by an ogonek (oþ).
>
> Please bear over with me if I am missing something basic here.

OK, I just experimented.... and you're right, that's what happens. 
You'll see the same thing (the o with the ogonek following instead of 
below) if you enter <o, U+0328> into WorldText, available in 
/Developer/Applications/Built Examples/ if you have the XCode Tools 
installed. That's because in Hoefler Text, the ogonek is not actually 
designed such that it overstrikes the previous letter, and there is no 
AAT table to position it there.

In TextEdit, the TeXShop editor, and many other applications, it looks 
OK; this is because the Cocoa text system actually overrides the font 
metrics and attempts to position diacritics on base characters without 
relying on AAT tables. This means that you get reasonable results even 
when the font fails to provide proper support. But this doesn't happen 
when text is rendered (as in XeTeX and WorldText) using the basic ATSUI 
APIs, which rely entirely on the font metrics and AAT tables.

So.... sorry, it's really a shortcoming of the font. You could write 
TeX macros to position the ogonek from Hoefler under the o, but it's 
messy and interrupts the nice clean Unicode text stream that we'd like 
to be able to use these days.

JK