[XeTeX] Checking for existence of font feature
michael.s.lynch at gmail.com
Wed Aug 11 21:54:00 CEST 2010
I'm trying to test for the existence of an OpenType font feature before
it's used in a document.
I want a command that will transparently emulate an acceptable
alternative in the event that the feature doesn't exist, whilst logging
the problem in the log file. Since the command is part of a package I'm
creating, I think this is preferable to it failing outright.
One of the features I'd like to test for is small caps. I'm not
optimistic, as in a plain XeTeX document,
\font\a="Times New Roman:+smcp" at 12pt
doesn't register as causing any problems, even though this call doesn't
produce anything different to
\font\a="Times New Roman" at 12pt
Have I missed something? opentype-info.tex iterates through all the
features, so there might be some way to check each one as it goes past,
but this does seem pretty laborious. I don't really have the experience
of TeX to know how to do something with that either though.
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