OpenType Std (TTF)
Features
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Access All Alternates
Tag:: aalt
Function:: This feature makes all variations of a selected character accessible. This serves several purposes: An application may not support the feature by which the desired glyph would normally be accessed; the user may need a glyph outside the context supported by the normal substitution, or the user may not know what feature produces the desired glyph. Since many-to-one substitutions are not covered, ligatures would not appear in this table unless they were variant forms of another ligature. A user inputs the P in Poetica, and is presented with a choice of the four standard capital forms, the eight swash capital forms, the initial capital form and the small capital form.
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Case-Sensitive Forms
Tag:: case
Function:: Shifts various punctuation marks up to a position that works better with all-capital sequences or sets of lining figures; also changes oldstyle figures to lining figures. By default, glyphs in a text face are designed to work with lowercase characters. Some characters should be shifted vertically to fit the higher visual center of all-capital or lining text. Also, lining figures are the same height (or close to it) as capitals, and fit much better with all-capital text. The user selects a block of text and applies this feature. The dashes, bracketing characters, guillemet quotes and the like shift up to match the capitals, and oldstyle figures change to lining figures.
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Fractions
Tag:: frac
Function:: Replaces figures separated by a slash with 'common' (diagonal) fractions. The user enters 3/4 in a recipe and gets the threequarters fraction.
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Standard Ligatures
Tag:: liga
Function:: Replaces a sequence of glyphs with a single glyph which is preferred for typographic purposes. This feature covers the ligatures which the designer/manufacturer judges should be used in normal conditions. The glyph for ffl replaces the sequence of glyphs f f l.
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Lining Figures
Tag:: lnum
Function:: This feature changes selected figures from oldstyle to the default lining form. The user invokes this feature in order to get lining figures, which fit better with all-capital text. Various characters designed to be used with figures may also be covered by this feature. In cases where lining figures are the default form, this feature would undo previous substitutions.
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Old Style Figures
Tag:: onum
Function:: This feature changes selected figures from the default lining style to oldstyle form. The user invokes this feature to get oldstyle figures, which fit better into the flow of normal upper- and lowercase text. Various characters designed to be used with figures may also have oldstyle versions.
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Proportional Figures
Tag:: pnum
Function:: Replaces figure glyphs set on uniform (tabular) widths with corresponding glyphs set on glyph-specific (proportional) widths. Tabular widths will generally be the default, but this cannot be safely assumed. Of course this feature would not be present in monospaced designs. The user may apply this feature to get even spacing for lining figures used as dates in an all-cap headline.
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Scientific Inferiors
Tag:: sinf
Function:: Replaces lining or oldstyle figures with inferior figures (smaller glyphs which sit lower than the standard baseline, primarily for chemical or mathematical notation). May also replace lowercase characters with alphabetic inferiors. The application can use this feature to automatically access the inferior figures (more legible than scaled figures).
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Superscript
Tag:: sups
Function:: Replaces lining or oldstyle figures with superior figures (primarily for footnote indication), and replaces lowercase letters with superior letters (primarily for abbreviated French titles). The application can use this feature to automatically access the superior figures (more legible than scaled figures) for footnotes, or the user can apply it to Mssr to get the classic form.
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Tabular Figures
Tag:: tnum
Function:: Replaces figure glyphs set on proportional widths with corresponding glyphs set on uniform (tabular) widths. Tabular widths will generally be the default, but this cannot be safely assumed. Of course this feature would not be present in monospaced designs. The user may apply this feature to get oldstyle figures to align vertically in a column.
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Small Capitals From Capitals
Tag:: c2sc
Function:: Small Capitals From Capitals
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Small Capitals
Tag:: smcp
Function:: This feature turns lowercase characters into small capitals. This corresponds to the common SC font layout. It is generally used for display lines set in Large & small caps, such as titles. Forms related to small capitals, such as oldstyle figures, may be included. The user enters text as mixed capitals and lowercase, and gets Large & small cap text.
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Ornaments
Tag:: ornm
Function:: This is a dual-function feature, which uses two input methods to give the user access to ornament glyphs (e.g. fleurons, dingbats and border elements) in the font. One method replaces the bullet character with a selection from the full set of available ornaments; the other replaces specific "lower ASCII" characters with ornaments assigned to them. The first approach supports the general or browsing user; the second supports the power user. The user inputs qwwwwwwwwwe to form the top of a flourished box in Adobe Caslon, or inputs the bullet character, then chooses the thistle dingbat.
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Discretionary Ligatures
Tag:: dlig
Function:: Replaces a sequence of glyphs with a single glyph which is preferred for typographic purposes. This feature covers those ligatures which may be used for special effect, at the user's preference. The glyph for ct replaces the sequence of glyphs c t, or U+322E (Kanji ligature for "Friday") replaces the sequence U+91D1 U+66DC U+65E5.
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Sylistic Set 1
Tag:: ss01
Function:: In addition to, or instead of, stylistic alternatives of individual glyphs (see 'salt' feature), some fonts may contain sets of stylistic variant glyphs corresponding to portions of the character set, e.g. multiple variants for lowercase letters in a Latin font. Glyphs in stylistic sets may be designed to harmonise visually, interract in particular ways, or otherwise work together. Examples of fonts including stylistic sets are Zapfino Linotype and Adobe's Poetica. Individual features numbered sequentially with the tag name convention 'ss01' 'ss02' 'ss03' . 'ss20' provide a mechanism for glyphs in these sets to be associated via GSUB lookup indexes to default forms and to each other, and for users to select from available stylistic sets.
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Sylistic Set 2
Tag:: ss02
Function:: In addition to, or instead of, stylistic alternatives of individual glyphs (see 'salt' feature), some fonts may contain sets of stylistic variant glyphs corresponding to portions of the character set, e.g. multiple variants for lowercase letters in a Latin font. Glyphs in stylistic sets may be designed to harmonise visually, interract in particular ways, or otherwise work together. Examples of fonts including stylistic sets are Zapfino Linotype and Adobe's Poetica. Individual features numbered sequentially with the tag name convention 'ss01' 'ss02' 'ss03' . 'ss20' provide a mechanism for glyphs in these sets to be associated via GSUB lookup indexes to default forms and to each other, and for users to select from available stylistic sets.
OpenType Std (CFF)
Features
-
Access All Alternates
Tag:: aalt
Function:: This feature makes all variations of a selected character accessible. This serves several purposes: An application may not support the feature by which the desired glyph would normally be accessed; the user may need a glyph outside the context supported by the normal substitution, or the user may not know what feature produces the desired glyph. Since many-to-one substitutions are not covered, ligatures would not appear in this table unless they were variant forms of another ligature. A user inputs the P in Poetica, and is presented with a choice of the four standard capital forms, the eight swash capital forms, the initial capital form and the small capital form.
-
Case-Sensitive Forms
Tag:: case
Function:: Shifts various punctuation marks up to a position that works better with all-capital sequences or sets of lining figures; also changes oldstyle figures to lining figures. By default, glyphs in a text face are designed to work with lowercase characters. Some characters should be shifted vertically to fit the higher visual center of all-capital or lining text. Also, lining figures are the same height (or close to it) as capitals, and fit much better with all-capital text. The user selects a block of text and applies this feature. The dashes, bracketing characters, guillemet quotes and the like shift up to match the capitals, and oldstyle figures change to lining figures.
-
Fractions
Tag:: frac
Function:: Replaces figures separated by a slash with 'common' (diagonal) fractions. The user enters 3/4 in a recipe and gets the threequarters fraction.
-
Standard Ligatures
Tag:: liga
Function:: Replaces a sequence of glyphs with a single glyph which is preferred for typographic purposes. This feature covers the ligatures which the designer/manufacturer judges should be used in normal conditions. The glyph for ffl replaces the sequence of glyphs f f l.
-
Lining Figures
Tag:: lnum
Function:: This feature changes selected figures from oldstyle to the default lining form. The user invokes this feature in order to get lining figures, which fit better with all-capital text. Various characters designed to be used with figures may also be covered by this feature. In cases where lining figures are the default form, this feature would undo previous substitutions.
-
Old Style Figures
Tag:: onum
Function:: This feature changes selected figures from the default lining style to oldstyle form. The user invokes this feature to get oldstyle figures, which fit better into the flow of normal upper- and lowercase text. Various characters designed to be used with figures may also have oldstyle versions.
-
Proportional Figures
Tag:: pnum
Function:: Replaces figure glyphs set on uniform (tabular) widths with corresponding glyphs set on glyph-specific (proportional) widths. Tabular widths will generally be the default, but this cannot be safely assumed. Of course this feature would not be present in monospaced designs. The user may apply this feature to get even spacing for lining figures used as dates in an all-cap headline.
-
Scientific Inferiors
Tag:: sinf
Function:: Replaces lining or oldstyle figures with inferior figures (smaller glyphs which sit lower than the standard baseline, primarily for chemical or mathematical notation). May also replace lowercase characters with alphabetic inferiors. The application can use this feature to automatically access the inferior figures (more legible than scaled figures).
-
Superscript
Tag:: sups
Function:: Replaces lining or oldstyle figures with superior figures (primarily for footnote indication), and replaces lowercase letters with superior letters (primarily for abbreviated French titles). The application can use this feature to automatically access the superior figures (more legible than scaled figures) for footnotes, or the user can apply it to Mssr to get the classic form.
-
Tabular Figures
Tag:: tnum
Function:: Replaces figure glyphs set on proportional widths with corresponding glyphs set on uniform (tabular) widths. Tabular widths will generally be the default, but this cannot be safely assumed. Of course this feature would not be present in monospaced designs. The user may apply this feature to get oldstyle figures to align vertically in a column.
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Small Capitals From Capitals
Tag:: c2sc
Function:: Small Capitals From Capitals
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Small Capitals
Tag:: smcp
Function:: This feature turns lowercase characters into small capitals. This corresponds to the common SC font layout. It is generally used for display lines set in Large & small caps, such as titles. Forms related to small capitals, such as oldstyle figures, may be included. The user enters text as mixed capitals and lowercase, and gets Large & small cap text.
-
Ornaments
Tag:: ornm
Function:: This is a dual-function feature, which uses two input methods to give the user access to ornament glyphs (e.g. fleurons, dingbats and border elements) in the font. One method replaces the bullet character with a selection from the full set of available ornaments; the other replaces specific "lower ASCII" characters with ornaments assigned to them. The first approach supports the general or browsing user; the second supports the power user. The user inputs qwwwwwwwwwe to form the top of a flourished box in Adobe Caslon, or inputs the bullet character, then chooses the thistle dingbat.
-
Discretionary Ligatures
Tag:: dlig
Function:: Replaces a sequence of glyphs with a single glyph which is preferred for typographic purposes. This feature covers those ligatures which may be used for special effect, at the user's preference. The glyph for ct replaces the sequence of glyphs c t, or U+322E (Kanji ligature for "Friday") replaces the sequence U+91D1 U+66DC U+65E5.
-
Sylistic Set 1
Tag:: ss01
Function:: In addition to, or instead of, stylistic alternatives of individual glyphs (see 'salt' feature), some fonts may contain sets of stylistic variant glyphs corresponding to portions of the character set, e.g. multiple variants for lowercase letters in a Latin font. Glyphs in stylistic sets may be designed to harmonise visually, interract in particular ways, or otherwise work together. Examples of fonts including stylistic sets are Zapfino Linotype and Adobe's Poetica. Individual features numbered sequentially with the tag name convention 'ss01' 'ss02' 'ss03' . 'ss20' provide a mechanism for glyphs in these sets to be associated via GSUB lookup indexes to default forms and to each other, and for users to select from available stylistic sets.
-
Sylistic Set 2
Tag:: ss02
Function:: In addition to, or instead of, stylistic alternatives of individual glyphs (see 'salt' feature), some fonts may contain sets of stylistic variant glyphs corresponding to portions of the character set, e.g. multiple variants for lowercase letters in a Latin font. Glyphs in stylistic sets may be designed to harmonise visually, interract in particular ways, or otherwise work together. Examples of fonts including stylistic sets are Zapfino Linotype and Adobe's Poetica. Individual features numbered sequentially with the tag name convention 'ss01' 'ss02' 'ss03' . 'ss20' provide a mechanism for glyphs in these sets to be associated via GSUB lookup indexes to default forms and to each other, and for users to select from available stylistic sets.