AAT Font Quality Specification
Appendix C. Font Feature Definitions for Localizers
This appendix describes the new feature registry. For the latest, up to
date font features see the 'Font Features Registry' page at 'fonts.apple.com'.
Each feature name is listed followed by its possible feature settings with
brief explanations. A selection of these items will be displayed in application
menus pertaining to AAT fonts, depending on the specific characteristics
of the font chosen and the language used. No single font will use all of
the possible features and settings. We expect only highly trained users,
knowledgeable about typography will want to use the settable features.
All of the specialized words should be translated into their equivalent
typographic terms in your language. You may find it best to work with a
professional typographer to find the best choices for terminology used
in their profession. If there are additional typographic features commonly
or occasionally used in your language or geographic region for which you
do not find an appropriate feature name or category, please let us know,
so that we can consider incorporating them into this comprehensive feature
registry.
All Typographic Features - the application will allow the user to specify
whether any typographic effects should occur.
Settings:
- All Type Features
- Ligatures - permits selection from different ranges of ligatures. A
ligature is a single symbol which represents two or more characters in
ordinary type.
-
Settings:
- Required Ligatures - ligatures are linguistically required (such as
in Arabic).
- Common Ligatures - ligatures are usually appear in well-set text.
- Rare Ligatures - ligatures that are less common.
- Logos - ligatures representing logotypes (e.g.trademarks).
- Rebus Pictures - ligatures that are pictures representing whole words
or syllables.
- Diphthong Ligatures - used to specify automatic creation of ligatures
like AE and OE.
-
Cursive Connection - used for cursively-connected scripts. It is required
for Arabic, but may be used for other scripts as well.
Settings:
- Unconnected - disables cursive connection.
- Partially Connected - used to select pre-drawn letter forms that connect
in a
- Noncontextual manner (look at the "Swing" font, for example).
- Cursive - selector is used to select full, contextual connection of
letter forms. This setting will be the default in Arabic fonts.
-
Letter Case - specifies changes to the case of letters (in scripts where
case has meaning), in either a contextual or a non-contextual manner.
Settings:
- Upper & Lower Case - leaves letters in whichever case the user
has specified. (default)
- All Caps - converts all letters (non-contextually) to the specified
form.
- All Lower Case - converts all letters (non-contextually) to the specified
form.
- Small Caps - specifies conversion of lower-case letters to small caps
forms.
- Initial Caps - specifies conversion of lower-case letters at the beginnings
of words into upper-case. (This is the only contextual selector in this
feature type.)
- Initial Caps & Small Caps - specifies conversion of lower-case
letters at the beginnings of words into upper-case followed by small caps.
-
Vertical Substitution - when enabled, glyphs change their appearance
in vertical runs of text.
Setting:
- Substitute Vertical Forms
-
Linguistic Rearrangement - when enabled, linguistic rearrangement of
glyphs occurs (as in South Asian scripts). The default is 'enabled' for
fonts representing these scripts.
Setting :
Number Spacing - specifies a choice for the appearance of digits.
Settings:
- Monospaced Numbers - each digit has uniform width; useful for displaying
in columns.
- Proportional Numbers - each digits has individual width.
-
Smart Swashes - controls contextual swash substitution.
Settings:
- Word Initials Swashes - swashes are substituted at the beginning of
words.
- Word Finals Swashes - swashes are substituted at the end of words.
- Line Initials Swashes -swashes are substituted at the beginning of
lines.
- Line Finals Swashes - swashes are substituted at the end of lines.
- Non-Final Swashes - specifies forms used at the beginning or middle
of words (such as the archaic long s) can be specified this way.
-
Diacritics - allows control over the appearance of diacritics (i.e.
accent marks or applied vowels) in text.
Settings:
- Show Diacritics - The default selector
- Hide Diacritics - do not show the marks. This option is useful in Arabic
children's book text, where the same text can be shown with vowels for
one audience or occasion and without vowels for another.
- Decompose Diacritics - do not attach the marks, but rather to place
them in-line with the rest of the text.
-
Vertical Position - controls things like superscripts and subscripts.
Settings:
- Normal Position - no modifications
- Superiors - used to map to alternate glyph forms, positioned differently
with respect to the baseline.
- Inferiors - see Superiors (above).
- Ordinals -contextually change attached ordinal marks (as, 1st into
1st- see example) into superior forms.
-
Fractions - controls the selection and/or generation of fractions.
Settings:
- No fractions - no fractions are to be automatically formed.
- Vertical Fractions - selects fractions that are present in the font
(pre-drawn) to replace a sequence of digit-/-digit.
- Diagonal Fractions - fractions will be synthesized via superiors and
inferiors and the fraction bar.
-
Overlapping Characters - permits the user to prevent the collision of
long tails on characters with other characters.
Settings:
- Prevent Overlap- prevents overlapping characters
-
Typographic Extras - a collection of effects that are associated with
fine typography.
Settings:
- Hyphens to Em Dash - causes two adjacent hyphens to change into a single
em dash.
- Hyphen to En Dash - changes the hyphen in a space-hyphen-space or digit-hyphen-
digit group into an en dash.
- Unslashed Zero makes sure the unslashed zero is always used (even if
the font designates the slashed zero as default), of course assuming the
unslashed zero actually exists in the font.
- Form Interrobang -An interrobang is a punctuation mark invented in
the '60s which combines the form and the sense of an exclamation mark (or
"bang") and a question mark (or "interrogation mark").
-
As for translating the name, there are two courses of action, either
of which would make sense:
- Transliterate the pronunciation [in-TER-o-bang]
- In the target language, combine word fragments which mean "question"
or "question mark" with those which mean "exclamation"
or "exclamation mark"
Smart Quotes - replaces tick marks (' or ") with the correct, polarized
quotes that are contextual.
Mathematical Extras - a collection of effects useful in setting figures
and mathematics.
Settings:
- Hyphen To Minus - changes the hyphen in a space-hyphen-space or digit-hyphen-
digit group into a minus (note this overrides the effect of the Hyphen
to En Dash selector in the Typographic Extras feature type).
- Asterisk to Multiply - changes the * in a space-*-space group into
a multiplication sign.
- Slash to Divide - changes the / in a space-/-space group into a stacked
(dots over and under a horizontal line) glyph.
- Inequality Ligatures - changes the >= sequence into a single stacked
glyph and the <= sequence into a a single stacked glyph.
- Exponent - takes digits immediately following a ^ (caret) and changes
them into their superior forms.
-
Ornament Sets - specifies non-letter ornament sets of glyphs. For example,
fleurons or decorative borders could be represented by this feature type.
Settings:
- No Ornaments -no simple ornament mapping.
- Dingbats - chooses miscellaneous symbols such as arrows, stars, and
pointing hands used for occasional emphasis in display.
- Pi Characters - a set of related symbols designed for a particular
purpose (e.g. cartography or musical notation) which do not make up a formal
alphabet.
- Fleurons - ornaments in the shape of flowers, vine leaves, and so on.
- Decorative Borders - glyphs designed to be used in interlocking or
repeating patterns as borders for text.
- International Symbols - glyphs representing standard, internationally
recognizeable icons (for example, the circle with the bar through it representing
negation).
- Math Symbols - special symbols used in setting mathematics or logic
text.
-
Character Alternatives - select different sets of glyphs in a font.
For example, a font with twenty ampersands could place them in twenty selectors
under this feature type. Use of the Alternate Designs feature, however,
is preferred (when feasible).
Settings:
- No Alternatives - turns feature off. This selector should always be
the first setting.
Design Complexity - controls the overall appearance of a font. Its use
would allow a single font to contain plain, italic, calligraphic (chancery)
glyphs and more.
Settings:
- Design Level 1 - the default setting for any font which uses this feature
type
- Design Level 2 - the remaining levels progress from simpler ...
- Design Level 3 ...to
- Design Level 4 ...most
- Design Level 5 ...complex
-
Style Options - allows the font designer to group together collections
of non-contextual substitutions into named sets. (In an application, if
no designs are selected by the user, the No Style Options feature selector
should be chosen.)
Settings:
- No Style Options - gives plain text, such as when all features are
turned off in a Chancery font.
- Display Text - uses glyphs designed to emphasize the unique appearance
of the design at display sizes, typically above 24 point.
- Engraved Text - uses glyphs with contrasting strokes parallel to the
main strokes, particularly those designed to look like they're engraved
in stone
- Illuminated Caps - uses capital letter glyphs with decoration filling
the whitespace surrounding the glyph, in the manner used by medieval scribes.
- Titling Caps - specifies conversion of capital letters to a special
titling form.
- Tall Caps - Capitals that extend above the ordinary cap height.
-
Character Shape - is available for use with Chinese fonts to specify
Traditional or Simplified character forms. If no other feature seems appropriate,
Character Shape might be used with other, possibly Roman, fonts to include
multiple forms of the same character (if the font has two different forms
of "A", the simplified version of which might not have a crossbar).
Settings:
- Traditional Characters - used to display Traditional Chinese characters.
- Simplified Characters - used to display Simplified Chinese characters.
-
Number Case - should be addressed under this feature type.
Settings:
- Upper Case refers to digits that do not descend below the baseline,
also called "lining"
- Lower Case digits (also called "traditional") may descend
below the baseline.
-
Arleigh Movitz
The Apple Fonts Group
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