Will Robertson wrote:
But please note
that this feature is essentially deprecated: it is better for a font
designer to use stylistic sets instead.
Why? If they are "historical forms" isn't it better to give them a
meaningful OpenType feature name?
I think what Alexey is referring to is that in use, it is more
convenient to set up stylistic sets. Example: the long s by itself
would go under "historical forms" but long s ligatures would go under
"historical ligatures." With a stylistic set, users can apply one
feature and get all the long s forms automatically. Of course, they
have to read the font documentation and find out what stylistic sets do
what (a terrible burden, expecting users to read the documentation . . .).
(I would not eliminate support for historical forms and historical
ligatures, though, since there are many fonts out there that use them.
You probably aren't planning to do that, but I just thought I'd mention it.)
You asked for an example of historical forms, and the long s is the most
obvious one, BTW.
4. I'm aware that I'm not fully covering the OpenType feature list
in fontspec. Has anyone noticed obvious areas that should be
included?
Am I right fontspec still doesn't support stylistic sets
(ss00--ss20), except via RawFeature?
This has always been available under the "Variant=0/1/2/3/..." feature
but this name wasn't very obvious. In more recent versions of fontspec
you can use "StylisticSet=0/1/2...".
Thank you, thank you. I hadn't picked up on this. The naming
conventions have always confused me, since there is a Fontspec feature
"Alternate" and "alternate" is also an option within the "Style"
feature, while stylistic sets were "Variants." Khaled in another email
mentioned that "variants" might be a more appropriate name for the
<salt> feature. Scholars do indeed speak of "glyph variants" For
example, U+2E0E EDITORIAL CORONIS (an ancient Greek papyrological
character) has five common variants, which can be (in some fonts!)
accessed through the stylistic alternates feature.
If clearer terminology could be found for all this, it would be a real
improvement.
Please ask if it looks like I've missed adding a feature in fontspec;
chances are I need to add code or documentation or both to the package.
In the last couple of days I have been thinking about using the
Character Variant feature (cv01-cv99) rather the stylistic alternate
feature for accessing glyphs such those I referred above. I haven't
gotten very far with this, but it might be something to add. (Does
anyone know of examples of this in use?)
David
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