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Font Features

This appendix describes font feature types and the selectors available for each feature type. In many cases, it also provides illustrations that show the effect of enabling a font feature or set of features. Before you read this appendix, you should be familiar with the font feature concepts discussed in detail in Chapter 3, “ATSUI Style and Text Layout Objects.”

Font features are available for a font only if the font designer chooses to include them. Many of the font features described here are rarely available. You should check with the font provider to see what features, if any, are available for a specific font.

The constants that represent font feature types and selectors are declared in the header file SFNTLayoutTypes.h. When you use ATSUI to access and set font features, you must use the constants defined in this header file, which are described in this appendix. Font designers can define feature types at any time. For the most up-to-date list of font feature types and selectors you should check Apple’s font feature registry website:

http://developer.apple.com/fonts/Registry/index.html

Contents:

All-Typographic Features Feature Type
Annotation Feature Type
Cursive Connection Feature Type
Character Alternatives Feature Type
Character Shape Feature Type
CJK Italic Roman Feature Type
CJK Roman Spacing Feature Type
Design Complexity Feature Type
Diacritical Marks Feature Type
Fractions Feature Type
Ideographic Spacing Feature Type
Kana Spacing Feature Type
Letter Case Feature Type
Ligatures Feature Type
Linguistic Rearrangement Feature Type
Mathematical Extras Feature Type
Number Case Feature Type
Number Spacing Feature Type
Ornament Sets Feature Type
Overlapping Glyphs Feature Type
Ruby Kana Feature Type
Smart Swashes Feature Type
Style Options Feature Type
Text Spacing Feature Type
Transliteration Feature Type
Typographical Extras Feature Type
Unicode Decomposition Feature Type
Vertical Position Feature Type
Vertical Substitution Feature Type

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