List of typographic features explained

Typographic features made possible using digital typographic systems have solved many of the demands placed on computer systems to replicate 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, LibreOffice/OpenOffice, 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 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 name	tag	type	Description
Above-base Forms	abvf	S1	Replaces the above-base part of a vowel sign. For Khmer and similar scripts.
Above-base Mark Positioning	abvm	P4,5	Positions a mark glyph above a base glyph.
Above-base Substitutions	abvs	S4	Ligates a consonant with an above-mark.
Below-base Forms	blwf	S4	Replaces halant+consonant combination with a subscript form.
Below-base Mark Positioning	blwm	P4,5	Positions a mark glyph below a base glyph
Below-base Substitutions	blws	S4	Ligates a consonant with a below-mark.
Pre-base Forms	pref	S4	Replaces halant+consonant at the end of a consonant cluster with a glyph at the beginning. Khmer, Myanmar, Malayalam, Telugu
Pre-base Substitutions	pres	S4,5	Ligates consonant combinations.
Post-base Substitutions	psts	S4	Ligates a final consonant+consonant.
Post-base Forms	pstf	S4	Substitutes final halant+consonant with special form. Khmer and Gurmukhi, Malayalam
Distance	dist	P2	Adjusts horizontal positioning between glyphs. (Always enabled, as opposed to 'kern'.)
Akhand	akhn	S4	Hindi for unbreakable. Ligates consonant+halant+consonant, usually only for k-ss and j-ny combinations.
Halant Forms	haln	S4	Replaces a glyph for final consonant+halant.
Half Form	half	S4	Replaces consonant+halant with a half form, indicating it is part of a conjunct.
Nukta Forms	nukt	S4	Replace consonant+nukta (dot mark) with single glyph.
Rakar Forms	rkrf	S4	Replaces halant+ra with a rakar glyph, indicating it is part of a conjunct.
Reph Form	rphf	S4	Replaces initial ra+halant with a final reph mark, indicating part of a conjunct.
Vattu Variants	vatu	S4	Replaces consonant+rakar combinations with a vattu variant ligature.
Conjunct Forms	cjct	S4	Ligates consonant+halant+consonant, indicates part of a conjunct.
Conjunct Form After Ro	cfar	S1	Khmer

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

Long name	tag	type	Description
Simplified Forms	smpl	S1	Replaces sinograms with their simplified versions, may be language dependent
Traditional Forms	trad	S1,3	Replaces Chinese characters with their traditional versions
Traditional Name Forms	tnam	S1	Japanese alternates for proper names
Expert Forms	expt	S1	Typographic alternatives for some Japanese tetragrams
Hojo Kanji Forms	hojo		Hojo alternates for Japanese tetragrams
NLC Kanji Forms	nlck		NLC alternates for Japanese tetragrams
JIS 78 Forms	jp78	S1,3	JIS C 6226-1978 alternates for Japanese tetragrams, not accessible per Unicode
JIS 83 Forms	jp83	S1	JIS X 0208-1983 alternates for Japanese tetragrams, not accessible per Unicode
JIS 90 Forms	jp90	S1	JIS X 0208-1990 alternates for Japanese tetragrams, not accessible per Unicode
JIS 04 Forms	jp04		JIS 2004 alternates for Japanese tetragrams, not accessible per Unicode
Hangul	hngl	S1,3	Transliterates Chinese-style characters with Korean Hangul
Leading Jamo Forms	ljmo	S4	Initial group of consonants for a synthesized Korean Hangul tetragram
Trailing Jamo Forms	tjmo	S4	Final group of consonants for a synthesized Korean Hangul tetragram
Vowel Jamo Forms	vjmo	S4	Medial group of vowels for a synthesized Korean Hangul tetragram
Full Widths	fwid	S1	Substitutes proportionally spaced character with full-width versions (esp. for Latin letters within Chinese)
Half Widths	hwid	S1,P1	Substitutes uniformly-spaced characters with half-width version
Alternate Half Widths	halt	P1	Re-positions full-width glyphs on half-width spaces
Third Widths	twid	S1,P1	Substitutes uniformly-spaced character with a version of 1/3 width (punctuation, etc.)
Quarter Widths	qwid	S1	Replaces uniformly-spaced glyphs with quarter-width ones (punctuation etc.)
Proportional Widths	pwid	S1	Replaces uniformly-spaced glyphs with proportional ones
Proportional Alternates	palt	P1	Re-positions otherwise monospace characters according to glyph width
Proportional Kana	pkna	S1	Kana for use alongside alphabets, without grid typography
Ruby Notation Forms	ruby	S1	Ruby characters, small print
Horizontal Kana Alternates	hkna	S1	Alternate forms for horizontal kana text, e.g. ー for chōonpu instead of ｜, cf. vkna
Vertical Kana	vkna	S1	Alternate Japanese kana forms for vertical text, e.g. ｜ for chōonpu instead of ー, cf. hkna
Centered CJK Punctuation	cpct	P1	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 name	tag	type	Description
Cursive Positioning	curs	P3	Precise positioning of a letter's connection to an adjacent one
Justification Alternates	jalt	S3	User selectable wider and narrower alternates, used especially for justifying
Mark Positioning via Substitution	mset	S5	Used in Windows 95 for positioning of Arabic marks
Required Contextual Alternates	rclt	S6	Contextual alternates required for correct text display which differs from the default join for other letters, required especially important by Arabic
Required Ligatures	rlig	S3	Ligatures required for correct text display (any script, but in cursive)
Isolated Forms	isol	S1	Substitutes a special form of a letter occurring outside a word (required by Arabic and Syriac)
Initial Forms	init	S1	Substitutes a special form of a letter occurring at the beginning of a word (required by Arabic and Syriac)
Medial Forms	medi	S1	Substitutes a special form of letters between other letters in words (required by Arabic and Syriac)
Medial Form #2	med2	S5	Syriac
Terminal Forms	fina	S1	Substitutes a special form of a letter at end of words (required by Arabic and Syriac)
Terminal Form #2	fin2	S5	Syriac
Terminal Form #3	fin3	S5	Syriac
Final Glyph on Line Alternates	falt	S3	Replaces final glyph on the line with an alternate
Stretching Glyph Decomposition	stch	S2	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 name	tag	type	Description
Small Caps	smcp	S1	Substitutes lower-case letters with small caps versions
Capitals to Small Caps	c2sc	S1	Substitutes capital letters with small caps
Petite Caps	pcap	S1	Substitute lower-case letters with their petite caps analogs
Capitals to Petite Caps	c2pc	S1	Substitutes capital letters with petite caps
Unicase	unic	S1	Replaces lowercase and uppercase letters with a set of single case glyphs
Capital Spacing	cpsp	P1	Adjusts spacing between letters in all-capitals text
Case Sensitive Forms	case	P1	Replace characters, especially punctuation, with forms better suited for all-capital text, cf. titl
Italics	ital	S1	Replaces letter with corresponding italic glyph
Ordinals	ordn	S6,4	Replaces characters with ordinal forms for use after numbers

Features depending on writing direction

Long name	tag	type	Description
Alternative Vertical Metrics	valt	P1	Positions shorter characters to be centered vertically with full-height characters
Alternative Vertical Half Metrics	vhal	P1	Positions characters to be centered vertically with half-height characters
Proportional Alternate Vertical Metrics	vpal	P1	Re-positions glyphs vertically to be centered on proportional full-height characters
Vertical Alternates	vert	S1	A subset of vrt2: prefer the latter feature
Vertical Alternates and Rotation	vrt2	S1	Replaces characters with forms suitable for vertical writing, possibly by rotating 90°
Vertical Alternates for Rotation	vrtr	S1	Replaces characters with forms suitable for vertical writing, possibly by shifting or shape
Vertical Kerning	vkrn	P2,8	Fine vertical positioning of characters based on shape
Left-to-right glyph alternates	ltra	S1	Replaces characters with forms befitting left-to-right presentation (except mirrored forms)
Left-to-right mirrored forms	ltrm	S1	Replaces characters with possibly mirrored forms befitting left-to-right presentation
Right-to-left glyph alternates	rtla	S1	Replaces characters with forms befitting right-to-left presentation (except mirrored forms)
Right-to-left mirrored forms	rtlm	S1	Replaces characters with possibly mirrored forms befitting right-to-left presentation

Features intended for digits and math

Long name	tag	type	Description
Lining Figures	lnum	S1	Replaces numerals with glyphs meant to fit better in all-capitals text, often also tnum
Oldstyle Figures	onum	S1	Replaces numerals with cased old-style numerals, often also pnum
Proportional Figures	pnum	S1	Replaces numerals with glyphs of proportional width, often also onum
Tabular Figures	tnum	S1	Replaces numerals with glyphs of uniform width, often also lnum
Fractions	frac	S4	Converts figures separated by slash with diagonal fraction
Alternative Fractions	afrc	S4	Converts figures separated by slash with alternative stacked fraction form
Denominator	dnom	S1	Converts to appropriate fraction denominator form, invoked by frac
Numerator	numr	S1	Converts to appropriate fraction numerator form, invoked by frac
Scientific Inferiors	sinf	S1	as in "H2O", "SOx" or "YCbCr" (but using the same font weight and predefined position in contrast these plain HTML subs and sups)
Slashed Zero	zero	S1	Replaces 0 figure with slashed 0
Mathematical Greek	mgrk	S1	Replaces Greek characters with special forms for use in mathematics
Flattened accent forms	flac		This feature is applied to individual glyphs during layout of math formula.
Dotless Forms	dtls		The dotless forms are to be used as base forms for placing mathematical accents over them.
Math script style alternates	ssty		This feature can have a parameter indicating the script level: 1 for simple subscripts and superscripts, 2 for second level subscripts and superscripts (that is, scripts on scripts), and so on. (Currently, only the first two alternates are used). For glyphs that are not covered by this feature, the original glyph is used in subscripts and superscripts.

Ligation and alternate forms features intended for all scripts

Long name	tag	type	Description
Access All Alternates	aalt	S1,3	Special feature: used to present user with choice all alternate forms of the character
Swash	swsh	S1,3	Either replaces character with or displays multiple swashed versions
Contextual Swash	cswh	S8	Converts letter to a swashed version based on characters around the letter
Contextual Alternates	calt	S6	Applies a second substitution feature based on a match of a character pattern within a context of surrounding patterns
Historical Forms	hist	S1	Obsolete forms of characters to be applied at the user's discretion, cf. hlig
Localized Forms	locl	S1	Substitutes character with the preferred form based on script language
Randomize	rand	S3	Replaces character with random forms (meant to simulate handwriting)
Alternate Annotation Forms	nalt	S1,3	Provides user access to circled digits, inverse letters etc.
Character Variant 1–99	cv01–<br />cv99	S3	Multiple variants of a single character, which may not apply to many other characters, see references for voluminous documentation
Stylistic Alternates	salt	S1,3	Either replaces with, or displays list of, stylistic alternatives for a character
Stylistic Set 1 – 20	ss01-<br>ss20	S1	Replaces character with one from a font-specific set of stylistic alternatives
Subscript	subs	S1	Replaces character with subscript version, cf. numr
Superscript	sups	S1	Replaces character with superscript version, cf. dnom
Titling Alternates	titl	S1	Replaces characters with forms suited for large type, as in titles
Required Variation Alternates	rvrn	S1	Special variants of a single character, which need apply to specific font variation, required by variable fonts
Contextual Ligatures	clig	S8	Applies a second ligature feature based on a match of a character pattern within a context of surrounding patterns
Discretionary Ligatures	dlig	S4	Ligatures to be applied at the user's discretion
Historical Ligatures	hlig	S1	Obsolete ligatures to be applied at the user's discretion
Standard Ligatures	liga	S4	Replaces (by default) sequence of characters with a single ligature glyph

Positioning features intended for all scripts

Long name	tag	type	Description
Glyph Composition/Decomposition	ccmp	S4,2	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.
Kerning	kern	P2,8	Fine horizontal positioning of one glyph to the next, based on the shapes of the glyphs
Mark Positioning	mark	P4,5	Fine positioning of a mark glyph to a base character
Mark-to-mark Positioning	mkmk	P6	Fine positioning of a mark glyph to another mark character
Optical Bounds	opbd	P1	Re-positions glyphs at beginning and end of line, for precise justification of text.
Left Bounds	lfbd	P1	Re-positions glyphs at end of line. Called by opbd.
Right Bounds	rtbd	P1	Re-positions glyphs at beginning of line. Called by opbd.

Special features intended for all scripts

Long name	tag	type	Description
Optical size	size		Not a lookup: feature's table provides to applications information about the appearance and intent of the font, to aid in font selection.
Ornaments	ornm	S3,1	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.	type	description
S1	GSUB 1	simple substitution of one glyph with another
S2	GSUB 2	multiple substitution of one character by several glyphs
S3	GSUB 3	variant selection
S4	GSUB 4	ligatures
S5	GSUB 5	contextual substitution
S6	GSUB 6	chained contextual substitution
S7	GSUB 7	extension for GSUB tables past 64kB
S8	GSUB 8	reverse chained contextual substitution
P1	GPOS 1	positioning of single glyph
P2	GPOS 2	positioning of pair of glyphs
P3	GPOS 3	cursive attachment
P4	GPOS 4	positioning of mark glyphs relative to base
P5	GPOS 5	positioning of mark glyphs relative to ligature
P6	GPOS 6	positioning of mark glyphs relative to another mark glyph
P7	GPOS 7	contextual positioning
P8	GPOS 8	extended contextual positioning
P9	GPOS 9	extension 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<!--cpsp-->
  • 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
  • No Transliteration
  • Hanja to Hangul
  • Hanja to Hangul, Alternative Set 1…3
  • Hiragana to Katakana
  • Katakana to Hiragana
  • Kana to Romanization
  • Romanization to Hiragana
  • Romanization to Katakana
• 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

External links

• • – AAT layout tag specs