[XeTeX] new use of alternate glyphs and how to turn them off

[Roland Kuhn]

On Oct 16, 2010, at 22:46 , Jonathan Kew wrote:

> On 16 Oct 2010, at 21:17, Fr. Michael Gilmary wrote:
> 
>> Hi Everyone:
>> 
>> I've noticed that since installing MacTeX2010, some alternate glyphs are selected without my permission! They're lovely, to be sure, but it's really a control issue for me ....
>> 
>> Is this a new feature of fontspec? or ?
>> 
>> Here's the example from a document compiled some time ago (June of 09 ... which was TL08) and you'll see the difference with the capital Q.
>> 
>> I haven't noticed any other changes. This is loaded with:
>> 
>> \defaultfontfeatures{Mapping=tex-text}
>> \setmainfont[Numbers={Proportional,OldStyle}]{Garamond Premier Pro}
>> 
>> The Q alternate only has a GID and no unicode point.
>> 
>> otfinfo -v GaramondPremrPro.otf
>> Version 2.000;PS 2.000;hotconv 1.0.50;makeotf.lib2.0.16970
>> 
> 
> The swash Q (which seems to be used only when it is followed by 'u') is a "contextual alternate" in Garamond Premier Pro. This feature is supposed to be active by default, according to the OpenType spec (see <http://www.microsoft.com/typography/otspec/features_ae.htm#calt>), but was not enabled in the older version of xetex.
> 
> So the new version is more correctly implementing the font designer's intent. However, if you want to turn it off, I'm sure fontspec has an option to disable the Contextual Alternates feature.
> 
You're right, Contextuals=NoAlternate works. Thanks for the clarification.

Roland

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