OpenType Features Reference

This document provides a comprehensive reference for OpenType features based on the Microsoft OpenType specification.

Feature Table

Key	Name	Description	Preview Text
`aalt`	Access All Alternates	Provides access to all alternates in the font	`Abc`
`abvf`	Above-base Forms	Forms positioned above the base character	`क` + marks
`abvm`	Above-base Mark Positioning	Positioning of marks above the base character	`á`
`abvs`	Above-base Substitutions	Substitutions for forms above the base character	`क` + marks
`afrc`	Alternative Fractions	Alternative fraction forms	`1/2 3/4`
`akhn`	Akhand	Conjunct forms that cannot be broken	`क्ष` (Devanagari)
`apkn`	Kerning for Alternate Proportional Widths	Kerning for proportional width alternates	`To AV`
`blwf`	Below-base Forms	Forms positioned below the base character	`क` + nukta
`blwm`	Below-base Mark Positioning	Positioning of marks below the base character	`ạ`
`blws`	Below-base Substitutions	Substitutions for forms below the base character	`क` + nukta
`calt`	Contextual Alternates	Context-sensitive alternate forms	`- -> --> = => ==>`
`case`	Case-sensitive Forms	Forms that are sensitive to case	`(ABC)`
`ccmp`	Glyph Composition / Decomposition	Composition and decomposition of glyphs	`á ö`
`cfar`	Conjunct Form After Ro	Conjunct forms that appear after "ro"	`r` + `क`
`chws`	Contextual Half-width Spacing	Context-sensitive half-width spacing	`カタカナ`
`cjct`	Conjunct Forms	Conjunct forms for Indic scripts	`क्ष`
`clig`	Contextual Ligatures	Context-sensitive ligatures	`st`
`cpct`	Centered CJK Punctuation	Centered punctuation for CJK scripts	`。「」`
`cpsp`	Capital Spacing	Spacing adjustments for capital letters	`TITLE`
`cswh`	Contextual Swash	Context-sensitive swash forms	`Q J`
`curs`	Cursive Positioning	Positioning for cursive connections	`السلام`
`cv01` - `cv99`	Character Variants 1-99	Character variants numbered 1 through 99	`1` ~ `99`
`c2pc`	Petite Capitals From Capitals	Petite capitals derived from capital letters	`ABC`
`c2sc`	Small Capitals From Capitals	Small capitals derived from capital letters	`ABC`
`dist`	Distances	Distance adjustments between characters	`To AV`
`dlig`	Discretionary Ligatures	Optional ligatures for aesthetics	`ct st`
`dnom`	Denominators	Denominator forms for fractions	`1/2`
`dtls`	Dotless Forms	Dotless forms (i, j)	`i j`
`expt`	Expert Forms	Expert typographic forms	`ct st`
`falt`	Final Glyph on Line Alternates	Alternates for final glyphs at line end	`word`
`fin2`	Terminal Forms #2	Second set of terminal forms	`سلام`
`fin3`	Terminal Forms #3	Third set of terminal forms	`سلام`
`fina`	Terminal Forms	Terminal forms for Arabic scripts	`سلام`
`flac`	Flattened Accent Forms	Flattened accent characters	`â ê ô`
`frac`	Fractions	Fraction forms	`1/2 3/4`
`fwid`	Full Widths	Full-width forms	`ABC123`
`half`	Half Forms	Half-width forms	`क`
`haln`	Halant Forms	Halant forms for Indic scripts	`क्`
`halt`	Alternate Half Widths	Alternate half-width forms	`カタカナ`
`hist`	Historical Forms	Historical forms	`ſ`
`hkna`	Horizontal Kana Alternates	Horizontal kana alternate forms	`カタカナ`
`hlig`	Historical Ligatures	Historical ligatures	`ct st`
`hngl`	Hangul	Hangul script forms	`한글`
`hojo`	Hojo Kanji Forms	JIS X 0212-1990 Kanji	`亜唖`
`hwid`	Half Widths	Half-width forms	`ＡＢＣ`
`init`	Initial Forms	Initial forms for Arabic scripts	`سلام`
`isol`	Isolated Forms	Isolated forms for Arabic scripts	`س`
`ital`	Italics	Italic character forms	`abc`
`jalt`	Justification Alternates	Alternates for text justification	`— —`
`jp78`	JIS78 Forms	JIS78 standard forms	`旧`
`jp83`	JIS83 Forms	JIS83 standard forms	`旧`
`jp90`	JIS90 Forms	JIS90 standard forms	`旧`
`jp04`	JIS2004 Forms	JIS2004 standard forms	`旧`
`kern`	Kerning	Kerning adjustments between pairs	`To AV`
`lfbd`	Left Bounds	Left boundary adjustments	`AV`
`liga`	Standard Ligatures	Standard ligatures	`fi fl ffi`
`ljmo`	Leading Jamo Forms	Leading jamo forms for Hangul	`가`
`lnum`	Lining Figures	Lining (uppercase) figures	`1234567890`
`locl`	Localized Forms	Localized character forms	`i İ`
`ltra`	Left-to-right Alternates	Left-to-right alternate forms	`→`
`ltrm`	Left-to-right Mirrored Forms	Left-to-right mirrored forms	`→`
`mark`	Mark Positioning	Positioning of diacritics	`á ö`
`med2`	Medial Forms #2	Second set of medial forms	`سلام`
`medi`	Medial Forms	Medial forms for Arabic scripts	`سلام`
`mgrk`	Mathematical Greek	Mathematical Greek characters	`∑ ∆ π`
`mkmk`	Mark to Mark Positioning	Positioning of marks relative to other marks	`ā́`
`mset`	Mark Positioning via Substitution	Mark positioning through substitution	`à́`
`nalt`	Alternate Annotation Forms	Alternate annotation forms	`a`
`nlck`	NLC Kanji Forms	NLC Kanji standard forms	`令`
`nukt`	Nukta Forms	Nukta forms for Indic scripts	`क़`
`numr`	Numerators	Numerator forms for fractions	`1/2`
`onum`	Oldstyle Figures	Oldstyle figures	`1234567890`
`opbd`	Optical Bounds	Optical boundary adjustments	`AV`
`ordn`	Ordinals	Ordinal number forms	`No.`
`ornm`	Ornaments	Ornamental character forms	`❦ ✤`
`palt`	Proportional Alternate Widths	Proportional alternate width forms	`1234`
`pcap`	Petite Capitals	Petite capital letter forms	`Abc`
`pkna`	Proportional Kana	Proportional kana forms	`カタカナ`
`pnum`	Proportional Figures	Proportional figure forms	`123456`
`pref`	Pre-base Forms	Forms positioned before the base character	`क`
`pres`	Pre-base Substitutions	Substitutions before the base character	`क`
`pstf`	Post-base Forms	Forms positioned after the base character	`क`
`psts`	Post-base Substitutions	Substitutions after the base character	`क`
`pwid`	Proportional Widths	Proportional width forms	`１２３`
`qwid`	Quarter Widths	Quarter-width character forms	`１２３`
`rand`	Randomize	Random character selection	`text`
`rclt`	Required Contextual Alternates	Required contextual alternates	`th`
`rkrf`	Rakar Forms	Rakar forms for Indic scripts	`क्र`
`rlig`	Required Ligatures	Required ligature forms	`lam-alef`
`rphf`	Reph Form	Reph form for Indic scripts	`र्`
`rtbd`	Right Bounds	Right boundary adjustments	`AV`
`rtla`	Right-to-left Alternates	Right-to-left alternate forms	`←`
`rtlm`	Right-to-left Mirrored Forms	Right-to-left mirrored forms	`←`
`ruby`	Ruby Notation Forms	Ruby annotation forms	`漢(かん)`
`rvrn`	Required Variation Alternates	Required variation alternate forms	`a`
`salt`	Stylistic Alternates	Stylistic alternates	`a g`
`sinf`	Scientific Inferiors	Scientific inferior forms	`H2O`
`size`	Optical Size	Optical size adjustments	`Text`
`smcp`	Small Capitals	Small capital letter forms	`abc`
`smpl`	Simplified Forms	Simplified character forms	`國 → 国`
`ss01` - `ss20`	Stylistic Sets 1-20	Stylistic sets numbered 1–20	`a g`
`ssty`	Math Script-style Alternates	Mathematical script-style alternates	`x y`
`stch`	Stretching Glyph Decomposition	Stretching glyph decomposition	`ــ`
`subs`	Subscript	Subscript forms	`x2`
`sups`	Superscript	Superscript forms	`x2`
`swsh`	Swash	Swash character forms	`Q J`
`titl`	Titling	Titling character forms	`Title`
`tjmo`	Trailing Jamo Forms	Trailing jamo forms for Hangul	`ᆨ`
`tnam`	Traditional Name Forms	Traditional name character forms	`舊`
`tnum`	Tabular Figures	Tabular figure forms	`123456`
`trad`	Traditional Forms	Traditional character forms	`國`
`twid`	Third Widths	Third-width character forms	`１２３`
`unic`	Unicase	Unicase character forms	`Aa`
`valt`	Alternate Vertical Metrics	Alternate vertical metric forms	`カタカナ`
`vapk`	Kerning for Alternate Proportional Vertical Metrics	Kerning for proportional vertical metrics	`カタカナ`
`vatu`	Vattu Variants	Vattu variant forms	`क`
`vchw`	Vertical Contextual Half-width Spacing	Vertical contextual half-width spacing	`カタカナ`
`vert`	Vertical Alternates	Vertical alternate forms	`漢字`
`vhal`	Alternate Vertical Half Metrics	Alternate vertical half metric forms	`カタカナ`
`vjmo`	Vowel Jamo Forms	Vowel jamo forms for Hangul	`ᅡ`
`vkna`	Vertical Kana Alternates	Vertical kana alternate forms	`カタカナ`
`vkrn`	Vertical Kerning	Vertical kerning adjustments	`カナ`
`vpal`	Proportional Alternate Vertical Metrics	Proportional alternate vertical metrics	`カタカナ`
`vrt2`	Vertical Alternates and Rotation	Vertical alternates with rotation	`漢字`
`vrtr`	Vertical Alternates for Rotation	Vertical alternates for rotation	`漢字`
`zero`	Slashed Zero	Slashed zero character form	`0`

Usage Notes

Character Variants (cv01-cv99): These features provide numbered character variants that can be used for different stylistic purposes.
Stylistic Sets (ss01-ss20): These features group related stylistic alternates together for easier application.
Contextual Features: Features like calt, clig, and chws are context-sensitive and apply based on surrounding characters.
Script-Specific Features: Many features are designed for specific writing systems (Arabic, Indic, CJK, etc.).

Feature Table​

Usage Notes​

References​

Feature Table

Usage Notes

References