List of typographic features

State-of-the-art digital typographic systems have solved virtually all the demands of traditional typography and have expanded the possibilities with many new features. Three systems are in common use: OpenType, devised by Microsoft and Adobe, Apple's Apple Advanced Typography (AAT), and SIL's Graphite. The lists below provide information about OpenType and AAT features. Graphite does not have a fixed set of features; instead it provides a way for fonts to define their own features.

OpenType typographic features

The OpenType format defines a number of typographic features that a particular font may support. Some software, such as Adobe InDesign or recent versions of Lua/XeTeX, gives users control of these features, for example to enable fancy stylistic capital letters (swash caps) or to choose between ranging (full-height) and non-ranging (old-style, or lower-case) digits. Some web browsers also support OpenType features in accordance with the CSS Fonts Module Level 3 specification, which allows OpenType features to be set directly via the font-feature-settings property, or indirectly by means of higher-level mechanisms.

The following tables list the features defined in version 1.8.1 of the OpenType specification. The codes in the "type" column are explained after the tables. OpenType features may be applicable only to certain language scripts or specific languages, or in certain writing modes. The features are split into several tables accordingly.

Features primarily intended for or exclusively required by South-Asian alphasyllabaries (Indic/Brahmic)

Long nametagtypeDescription
Above-base FormsabvfS1 Replaces the above-base part of a vowel sign. For Khmer and similar scripts.
Above-base Mark PositioningabvmP4,5 Positions a mark glyph above a base glyph.
Above-base SubstitutionsabvsS4 Ligates a consonant with an above-mark.
Below-base FormsblwfS4 Replaces halant+consonant combination with a subscript form.
Below-base Mark PositioningblwmP4,5 Positions a mark glyph below a base glyph
Below-base SubstitutionsblwsS4 Ligates a consonant with a below-mark.
Pre-base FormsprefS4 Replaces halant+consonant at the end of a consonant cluster with a glyph at the beginning. Khmer, Myanmar, Malayalam, Telugu
Pre-base SubstitutionspresS4,5 Ligates consonant combinations.
Post-base SubstitutionspstsS4 Ligates a final consonant+consonant.
Post-base FormspstfS4 Substitutes final halant+consonant with special form. Khmer and Gurmukhi, Malayalam
DistancedistP2 Adjusts horizontal positioning between glyphs. (Always enabled, as opposed to 'kern'.)
AkhandakhnS4 Hindi for unbreakable. Ligates consonant+halant+consonant, usually only for k-ss and j-ny combinations.
Halant FormshalnS4 Replaces a glyph for final consonant+halant.
Half FormhalfS4 Replaces consonant+halant with a half form, indicating it is part of a conjunct.
Nukta FormsnuktS4 Replace consonant+nukta (dot mark) with single glyph.
Rakar FormsrkrfS4 Replaces halant+ra with a rakar glyph, indicating it is part of a conjunct.
Reph FormrphfS4 Replaces initial ra+halant with a final reph mark, indicating part of a conjunct.
Vattu VariantsvatuS4 Replaces consonant+rakar combinations with a vattu variant ligature.
Conjunct FormscjctS4 Ligates consonant+halant+consonant, indicates part of a conjunct.
Conjunct Form After RocfarS1 Khmer

Features primarily intended for or exclusively required by East-Asian tetragrams (Chinese, Japanese, Korean)

Long nametagtypeDescription
Simplified FormssmplS1 Replaces sinograms with their simplified versions, may be language dependent
Traditional FormstradS1,3 Replaces Chinese characters with their traditional versions
Traditional Name FormstnamS1 Japanese alternates for proper names
Expert FormsexptS1 Typographic alternatives for some Japanese tetragrams
Hojo Kanji Formshojo Hojo alternates for Japanese tetragrams
NLC Kanji Formsnlck NLC alternates for Japanese tetragrams
JIS 78 Formsjp78S1,3 JIS C 6226-1978 alternates for Japanese tetragrams, not accessible per Unicode
JIS 83 Formsjp83S1 JIS X 0208-1983 alternates for Japanese tetragrams, not accessible per Unicode
JIS 90 Formsjp90S1 JIS X 0208-1990 alternates for Japanese tetragrams, not accessible per Unicode
JIS 04 Formsjp04 JIS 2004 alternates for Japanese tetragrams, not accessible per Unicode
HangulhnglS1,3 Transliterates Chinese-style characters with Korean Hangul
Leading Jamo FormsljmoS4 Initial group of consonants for a synthesized Korean Hangul tetragram
Trailing Jamo FormstjmoS4 Final group of consonants for a synthesized Korean Hangul tetragram
Vowel Jamo FormsvjmoS4 Medial group of vowels for a synthesized Korean Hangul tetragram
Full WidthsfwidS1 Substitutes proportionally spaced character with full-width versions (esp. for Latin letters within Chinese)
Half WidthshwidS1,P1 Substitutes uniformly-spaced characters with half-width version
Alternate Half WidthshaltP1 Re-positions full-width glyphs on half-width spaces
Third WidthstwidS1,P1 Substitutes uniformly-spaced character with a version of 1/3 width (punctuation, etc.)
Quarter WidthsqwidS1 Replaces uniformly-spaced glyphs with quarter-width ones (punctuation etc.)
Proportional WidthspwidS1 Replaces uniformly-spaced glyphs with proportional ones
Proportional AlternatespaltP1 Re-positions otherwise monospace characters according to glyph width
Proportional KanapknaS1 Kana for use alongside alphabets, without grid typography
Ruby Notation FormsrubyS1 Ruby characters, small print
Horizontal Kana AlternateshknaS1 Alternate forms for horizontal kana text, e.g. ー for chōonpu instead of ｜, cf. vkna
Vertical KanavknaS1 Alternate Japanese kana forms for vertical text, e.g. ｜ for chōonpu instead of ー, cf. hkna
Centered CJK PunctuationcpctP1 Positions punctuation marks vertically and horizontally

Features primarily intended for or exclusively required by West-Asian (Semitic, Arabic) and other cursive scripts or fonts

Long nametagtypeDescription
Cursive PositioningcursP3 Precise positioning of a letter's connection to an adjacent one
Justification AlternatesjaltS3 User selectable wider and narrower alternates
Mark Positioning via SubstitutionmsetS5 Used in Windows 95 for positioning of Arabic marks
Required Contextual AlternatesrcltS6 Contextual alternates required for correct text display which differs from the default join for other letters, required especially important by Arabic
Required LigaturesrligS3 Ligatures required for correct text display (any script, but in cursive)
Isolated FormsisolS1 Substitutes a special form of a letter occurring outside a word (required by Arabic and Syriac)
Initial FormsinitS1 Substitutes a special form of a letter occurring at the beginning of a word (required by Arabic and Syriac)
Medial FormsmediS1 Substitutes a special form of letters between other letters in words (required by Arabic and Syriac)
Medial Form #2med2S5 Syriac
Terminal FormsfinaS1 Substitutes a special form of a letter at end of words (required by Arabic and Syriac)
Terminal Form #2fin2S5 Syriac
Terminal Form #3fin3S5 Syriac
Final Glyph on Line AlternatesfaltS3 Replaces final glyph on the line with an alternate.
Stretching Glyph DecompositionstchS2 Substitutes a special form of a stretchy glyph onto one or more letters (required by Syriac)

Features intended for bicameral [cased] alphabets (Latin, Greek, Cyrillic, etc.)

Long nametagtypeDescription
Small CapssmcpS1 Substitutes lower-case letters with small caps versions
Capitals to Small Capsc2scS1 Substitutes capital letters with small caps
Petite CapspcapS1 Substitute lower-case letters with their petite caps analogs
Capitals to Petite Capsc2pcS1 Substitutes capital letters with petite caps
UnicaseunicS1 Replaces lowercase and uppercase letters with a set of single case glyphs
Capital SpacingcpspP1 Adjusts spacing between letters in all-capitals text
Case Sensitive FormscaseP1 Replace characters, especially punctuation, with forms better suited for all-capital text, cf. titl
ItalicsitalS1 Replaces letter with corresponding italic glyph
OrdinalsordnS6,4 Replaces characters with ordinal forms for use after numbers

Features depending on writing direction

Long nametagtypeDescription
Alternative Vertical MetricsvaltP1 Positions shorter characters to be centered vertically with full-height characters
Alternative Vertical Half MetricsvhalP1 Positions characters to be centered vertically with half-height characters
Proportional Alternate Vertical MetricsvpalP1 Re-positions glyphs vertically to be centered on proportional full-height characters
Vertical AlternatesvertS1 A subset of vrt2: prefer the latter feature
Vertical Alternates and Rotationvrt2S1 Replaces characters with forms suitable for vertical writing, possibly by rotating 90°
Vertical Alternates for RotationvrtrS1 Replaces characters with forms suitable for vertical writing, possibly by shifting or shape
Vertical KerningvkrnP2,8 Fine vertical positioning of characters based on shape
Left-to-right glyph alternatesltraS1 Replaces characters with forms befitting left-to-right presentation (except mirrored forms)
Left-to-right mirrored formsltrmS1 Replaces characters with possibly mirrored forms befitting left-to-right presentation
Right-to-left glyph alternatesrtlaS1 Replaces characters with forms befitting right-to-left presentation (except mirrored forms)
Right-to-left mirrored formsrtlmS1 Replaces characters with possibly mirrored forms befitting right-to-left presentation

Features intended for digits and math

Long nametagtypeDescription
Lining FigureslnumS1 Replaces numerals with glyphs meant to fit better in all-capitals text, often also tnum
Oldstyle FiguresonumS1 Replaces numerals with cased old-style numerals, often also pnum
Proportional FigurespnumS1 Replaces numerals with glyphs of proportional width, often also onum
Tabular FigurestnumS1 Replaces numerals with glyphs of uniform width, often also lnum
FractionsfracS4 Converts figures separated by slash with diagonal fraction
Alternative FractionsafrcS4 Converts figures separated by slash with alternative stacked fraction form
DenominatordnomS1 Converts to appropriate fraction denominator form, invoked by frac
NumeratornumrS1 Converts to appropriate fraction numerator form, invoked by frac
Scientific InferiorssinfS1 as in "H2O", "SOx" or "YCbCr"
Slashed ZerozeroS1 Replaces 0 figure with slashed 0
Mathematical GreekmgrkS1 Replaces Greek characters with special forms for use in mathematics
Flattened accent formsflac
Dotless Formsdtls
Math script style alternatesssty

Ligation and alternate forms features intended for all scripts

Long nametagtypeDescription
Access All AlternatesaaltS1,3 Special feature: used to present user with choice all alternate forms of the character
SwashswshS1,3 Either replaces character with or displays multiple swashed versions
Contextual SwashcswhS8 Converts letter to a swashed version based on characters around the letter
Contextual AlternatescaltS6 Applies a second substitution feature based on a match of a character pattern within a context of surrounding patterns
Historical FormshistS1 Obsolete forms of characters to be applied at the user's discretion, cf. hlig
Localized FormsloclS1 Substitutes character with the preferred form based on script language
RandomizerandS3 Replaces character with random forms (meant to simulate handwriting)
Alternate Annotation FormsnaltS1,3 Provides user access to circled digits, inverse letters etc.
Character Variant 1–99cv01–
cv99		S3 Multiple variants of a single character, which may not apply to many other characters, see references for voluminous documentation
Stylistic AlternatessaltS1,3 Either replaces with, or displays list of, stylistic alternatives for a character
Stylistic Set 1 – 20ss01-
ss20		S1 Replaces character with one from a font-specific set of stylistic alternatives
SubscriptsubsS1 Replaces character with subscript version, cf. numr
SuperscriptsupsS1 Replaces character with superscript version, cf. dnom
Titling AlternatestitlS1 Replaces characters with forms suited for large type, as in titles
Required Variation AlternatesrvrnS1 Special variants of a single character, which need apply to specific font variation, required by variable fonts
Contextual LigaturescligS8 Applies a second ligature feature based on a match of a character pattern within a context of surrounding patterns
Discretionary LigaturesdligS4 Ligatures to be applied at the user's discretion
Historical LigatureshligS1 Obsolete ligatures to be applied at the user's discretion
Standard LigaturesligaS4 Replaces (by default) sequence of characters with a single ligature glyph

Positioning features intended for all scripts

Long nametagtypeDescription
Glyph Composition/DecompositionccmpS4,2 Either calls a ligature replacement on a sequence of characters or replaces a character with a sequence of glyphs. Provides logic that can for example effectively alter the order of input characters.
KerningkernP2,8 Fine horizontal positioning of one glyph to the next, based on the shapes of the glyphs
Mark PositioningmarkP4,5 Fine positioning of a mark glyph to a base character
Mark-to-mark PositioningmkmkP6 Fine positioning of a mark glyph to another mark character
Optical BoundsopbdP1 Re-positions glyphs at beginning and end of line, for precise justification of text.
Left BoundslfbdP1 Re-positions glyphs at end of line. Called by opbd.
Right BoundsrtbdP1 Re-positions glyphs at beginning of line. Called by opbd.

Special features intended for all scripts

Long nametagtypeDescription
Optical sizesize Not a lookup: feature's table provides to applications information about the appearance and intent of the font, to aid in font selection.
OrnamentsornmS3,1 Decorative alternates for the bullet character •

Legend of substitution and positioning codes

Below are listed the OpenType lookup table types, as used in the "type" column in the above tables. S stands for substitution, and P stands for positioning. Note that often a feature can be implemented by more than one type of table, and that sometimes the specification fails to explicitly indicate the table type.

abbrev.typedescription
S1GSUB 1simple substitution of one glyph with another
S2GSUB 2multiple substitution of one character by several glyphs
S3GSUB 3variant selection
S4GSUB 4ligatures
S5GSUB 5contextual substitution
S6GSUB 6chained contextual substitution
S7GSUB 7extension for GSUB tables past 64kB
S8GSUB 8reverse chained contextual substitution
P1GPOS 1positioning of single glyph
P2GPOS 2positioning of pair of glyphs
P3GPOS 3cursive attachment
P4GPOS 4positioning of mark glyphs relative to base
P5GPOS 5positioning of mark glyphs relative to ligature
P6GPOS 6positioning of mark glyphs relative to another mark glyph
P7GPOS 7contextual positioning
P8GPOS 8extended contextual positioning
P9GPOS 9extension for GPOS tables past 64kB

AAT typographic features

Features that take one value, mutual exclusive from the rest:

  • Annotation nalt
    • No Annotation
    • Box Annotation
    • Rounded Box Annotation
    • Circle Annotation
    • Inverted Circle Annotation
    • Parenthesis Annotation
    • Period Annotation
    • Roman Numeral Annotation
    • Diamond Annotation
  • Character Alternatives
    • No Alternates
    • … rand; aalt, calt, falt, jalt, salt, ssXX, hkna/vkna, rtla, vrt2
  • Character Shape half, ruby; ljmo, vjmo, tjmo
    • Traditional Characters trad
    • Simplified Characters smpl
    • JIS 1978 Characters jp78
    • JIS 1983 Characters jp83
    • JIS 1990 Characters jp90
    • Traditional Characters, Alternative Set 1…5 tnam, hojo, nlck
    • Expert Characters expt, locl
  • CJK Latin Spacing
    • Half-width hwid, halt
    • Proportional pwid, palt
    • Default Latin
    • Full-width Latin fwid
  • Cursive Connection init, medi/med2, fina/fin2/fin3; haln, nukt, vatu, rphf, pres, pstf/psts
    • Unconnected isol
    • Partially Connected calt, clig
    • Cursive curs
  • Design Complexity
    • Design Level 1
    • Design Level …
  • Diacritics
    • Show Diacritics
    • Hide Diacritics
    • Decompose Diacritics ccmp
  • Fractions
    • No Fractions
    • Vertical Fractions afrc
    • Diagonal Fractions frac, dnom, numr
  • Ideographic Spacing
    • Full Width fwid
    • Proportional pwid, palt
  • Kana Spacing
    • Full Width fwid
    • Proportional pwid, palt
  • Letter Case case
    • Upper & Lower Case
    • All Caps
    • All Lower Case
    • Small Caps smcp, pcap
    • Initial Caps c2sc, c2pc
    • Initial Caps and Small Caps
  • Number Case
    • Lower Case Numbers onum
    • Upper Case Numbers lnum
  • Number Spacing
    • Monospaced Numbers tnum
    • Proportional Numbers pnum
  • Ornament Sets ornm
    • None
    • Dingbats
    • Pi Characters
    • Fleurons
    • Decorative Borders
    • International Symbols
    • Math Symbols mgrk
  • Text Spacing
    • Proportional pwid, palt
    • Monospace fwid
    • Half-width hwid, halt
    • Normal
  • Vertical Position
    • No Vertical Position
    • Superiors supr
    • Inferiors subs, sinf
    • Ordinals ordn

Features that take a number of values:

  • Ligatures
    • Required Ligatures rlig, clig
    • Common Ligatures liga
    • Rare Ligatures hlig, dlig
    • Logos
    • Rebus Pictures
    • Diphthong Ligatures
    • Squared Ligatures
    • Squared Ligatures, Abbreviated
  • Mathematical Extras
    • Hyphen to Minus (‘-’ → ‘−’)
    • Asterisk to Multiply (‘*’ → ‘×’)
    • Slash to Divide (‘/’ → ‘÷’)
    • Inequality Ligatures
    • Exponents
  • Smart Swashes swsh, cswh
    • Word Initial Swashes
    • Word Final Swashes
    • Line Initial Swashes
    • Line Final Swashes falt
    • Non-Final Swashes jalt
  • Style Options
    • No Style Options
    • Display Text size
    • Engraved Text
    • Illuminated Caps
    • Titling Caps titl
    • Tall Caps
  • Transliteration locl
  • Typographic Extras
    • Hyphens to Em Dash (‘--’ → ‘—’)
    • Hyphen to En Dash (‘-’ → ‘–’)
    • Unslashed Zero zero
    • Form Interrobang (‘!?’/‘?!’ → ‘‽’)
    • Smart Quotes (‘"'"’ → ‘“’”’)
    • Periods to Ellipsis (‘...’ → ‘…’)

Binary features that can only be turned on:

  • All Typographic Features
  • Linguistic Rearrangement
  • Overlapping Characters
  • Vertical Substitution
  • "Layout tag registry", OpenType spec, Microsoft
  • "Font Feature Registry", Fonts, Apple – AAT layout tag specs
  • OpenType User Guide for Adobe Fonts (PDF), Adobe
  • OpenType user guide (PDF), Fontfont
  • An Introduction to OpenType Substitution Features, I love typography
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