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Fine typography: Numbers
Several glyph effects relate to numbers, and simple mathematical
typesetting. Note the word "simple": GX is not going to set integrals
for you.
Figures
The illustration below shows a typical selection of numeric glyphs:
A more complete Monospaced Numbers set might also include its
own monospaced mathematical and monetary symbols.
Number Spacing
The Number Spacing feature type specifies a choice for the appearance
of digits. Monospaced digits have uniform width and are useful
for displaying numbers in columns. Proportional digits may have
individual widths, and are thus preferred for numbers within sentences.
This is an exclusive feature: numbers have to be either monospaced
or proportional. Either one can be the default setting.
For the default setting (whichever one that is), you can leave
the editor blank. Note that all digits must be proportional or
all digits monospaced: you should not mix-and-match between the
two within a givensetting.
Monospaced Numbers
- Glyphs:
- Proportional numbers, monospaced numbers
- Effect:
- Substitutes monospaced numbers for proportional numbers in all
contexts.
- Editor:
- A standard one-to-one non-contextual editor, as shown in the "Small Capitals" example.
Proportional Numbers
- Glyphs:
- Monospaced numbers, proportional numbers
- Effect:
- Substitutes proportional numbers for monospaced numbers in all
contexts.
- Editor:
- A standard one-to-one non-contextual editor, as shown in the "Small Capitals" example.
Number Case
The Number Case feature type specifies a choice for the appearance
of digits. Number Case is independent of Letter Case. Lower Case
Numbers (also called "ranging", "traditional" or "old style")
are digits whose optical height is the same as that of the lower-case
letters in the font, and - like the lower case letters - can have
both ascenders and descenders.
Upper Case Numbers (also called "lining") on the other hand, have
neither ascenders nor descenders: all digits are usually the same
height as the capital letters in the font. Upper case numbers
are sometimes called "modern" digits.
This is an exclusive feature: numbers have to be either uppercase
or lowercase. Either one can be the default setting; that editor
should have no entries, and that effect should have its "is default"
checkbox checked. The default setting should correspond to the
style of numeric glyphs which are normally mapped to the characters
'0' to '9' in the font - don't set "Lower Case Numbers" as the
default if the font contains uppercase number glyphs.
Lower Case Numbers
- Glyphs:
- Uppercase numbers, lowercase numbers
- Effect:
- Substitutes lowercase numbers for uppercase numbers in all contexts.
- Editor:
- A standard one-to-one non-contextual editor, as shown in the "Small Capitals" example.
Upper Case Numbers
- Glyphs:
- Lowercase numbers, uppercase numbers
- Effect:
- Substitutes uppercase numbers for lowercase numbers in all contexts.
- Editor:
- A standard one-to-one non-contextual editor, as shown in the "Small Capitals" example.
Vertical Position
The Vertical Position feature type controls things like superscripts
and subscripts. The Superiors and Inferiors selectors are used
to map numerals to alternate glyph forms, positioned differently
with respect to the baseline. Superiors and Inferiors can certainly
be used for letters as well as numbers, but typically these settings
are only relevant in relation to numbers.
The Ordinals selector is used to contextually change attached
ordinal marks (such as "st" in "1st", or "ème" in "3ème") into superior forms.
Vertical Position is an exclusive feature, for which "Normal position"
must be the default setting.
There is no editor for Normal Position, as it should represent
the native state of any font.
Normal Position
- Glyphs:
- None
- Effect:
- None
- Editor:
- There is no editor for this effect. TrueEdit automatically creates
it when you create any of the other settings for Vertical Position
feature.
- Notes:
- This is the default setting and leaves numbers and letters on
the baseline.
Superiors
- Glyphs:
- Normal forms, superior forms
- Effect:
- Substitutes superior form glyphs for normal form glyphs in all
contexts.
- Editor:
- A standard one-to-one non-contextual editor, as shown in the "Small Capitals" example.
Inferiors
- Glyphs:
- Normal forms, inferior forms
- Effect:
- Substitutes inferior form glyphs for normal form glyphs in all
contexts.
- Editor:
- A standard one-to-one non-contextual editor, as shown in the "Small Capitals" example.
Ordinals
- Glyphs:
- Normal letters, superior letters, digits
- Effect:
- When a sequence of (up to 8) normal letter glyphs immediately
follows a digit glyph, Line Layout substitutes superior letter
glyphs for all of the normal letter glyphs.
- Editor:
- A unique contextual editor with three live areas for Digits, for
Letters, and for Superiors.
- Note:
- The end of the sequence of normal letter glyphs is determined
by the first glyph not in that class.
Fractions
The Fractions feature type controls the selection and/or generation
of fractions. The No Fractions selector specifies that fractions
should not be formed automatically. The Vertical Fractions selector
will form vertical fractions when glyphs are present in the font,
with horizontal fraction bars. The Diagonal Fractions synthesizes
fractions using numerator and denominator glyphs.
TrueEdit doesn't let you make a table which lets the end user
type a slash and have a fraction bar substituted for it. Fractions
composed with the slash bar will have equal spacing of numbers
and / on a single line. Such fractions cannot be affected by the
settings of the Fractions feature. Fractions composed with the
fraction bar (shift-option-1 on US and some other keyboards) will
look ugly with the fractions feature off, but will turn into nice
vertical or diagonal fractions (depending on the end user's choice
of effects) when the feature is selected.
This is an exclusive feature.
There's no editor for No Fractions, as it is the native state
of the font. However, any of the three fraction settings could
be the default.
Note that while diagonal fractions can certainly be used for letters
(for abbreviations such as c/o, t/a), they're mainly relevant
in relation to numbers.
No Fractions
This setting is normally the default for a font. Selecting No
Fractions will prevent any diagonal or vertical fractions from
being formed. The resulting flat, or "linear", fractions are as
shown below.
Note that in this case, the fraction bar is not as good a separator
as the forward slash. Because the fraction bar is meant to lie
between superior and inferior digits, not normal digits, it tends
to overlap normal-sized figures directly to its left and right.
- Glyphs:
- None
- Effect:
- None
- Editor:
- There is no editor for this effect. TrueEdit automatically creates
it when you create either of the other settings for the Fractions
feature.
Vertical Fractions
- Glyphs:
- Digits, fraction bar, vertical fractions
- Effect:
- When the three-glyph sequence of a numerator digit glyph, the
fraction bar glyph, and a denominator digit glyph occurs, a vertical
fraction glyph is substituted for that sequence.
- Editor:
- A standard many-to-one ligature editor, as shown in Example 2:
Common Ligatures. The middle glyph of the ligature should be the
fraction bar, in order to allow this feature to interoperate with
the Diagonal Fractions effect.
-
-
- Notes:
 Only fractions which exist in the font as individual glyphs can
be formed by the Vertical Fractions effect.
- The numerators and denominators must be single digits.
Diagonal Fractions
- Glyphs:
- Digits, numerators, denominators, fraction bar
- Effect:
- When a sequence of (up to 8) digit glyphs, the fraction bar glyph,
and (up to 8) digit glyphs occurs, ·numerator glyphs are substituted for the digit glyphs before the
fraction bar and denominator glyphs for the digit glyphs after
the fraction bar.
- Editor:
- Shown in the "Diagonal Fractions" example.
Mathematical Extras
The Mathematical Extras effects are useful in setting figures
and mathematics.
These features are cumulative: none, all, or any combination may
be on at one time.
Hyphen To Minus
- Glyphs:
- Hyphen, Minus.
- Effect:
- Changes the hyphen in a space-hyphen-space or digit-hyphen-digit
group into a minus
- Editor:
- A simple editor with two live areas: one for the hyphen character,
the other for the minus glyph with which it should be replaced.
- Notes:
- This overrides the effect of the Hyphen to En Dash selector in
the Typographic Extras feature type. Whichever comes first in
the font's mort table will take effect.
- Although the digit-hyphen-digit substitution is technically wrong,
the current version of TrueEdit adds it to the "Hyphen to Minus"
effect anyway. A digit-hyphen-digit group shouldn't qualify. A
space(or parenthesis, etc..)-hyphen-digit should.
Asterisk to Multiply
Glyphs:
- Asterisk, Multiplication sign.
- Effect:
- Changes the asterisk character in a space-asterisk-space group
into a multiplication sign.
- Editor:
- A simple editor with two live areas: one for the asterisk character,
the other for the multiplication-sign glyph with which it should
be replaced.
Slash to Divide
- Glyphs:
- Forward Slash, Division sign.
- Effect:
- changes the slash character in a digits-slash-digits group into
a division-sign glyph.
- Editor:
- A simple editor with two live areas: one for the forward-slash
character, the other for the division-sign glyph with which it
should be replaced.
- Notes:
- Because of a bug in TrueEdit, only a digit-slash-digit group qualifies
for division-sign substitution - more correctly, space-slash-space
sequences should be changed too.
Inequality Ligatures
- Glyphs:
- Equals, Less-than, Greater-than glyphs, Less-than-or-equal-to,
Greater-than-or-equal-to.
- Effect:
- Changes the >= sequence into a greater-than-or-equal-to glyph
and the <= sequence into a less-than-or-equal-to glyph.
- Editor:
- A unique editor with live areas for the equals, less-than and
greater-than glyphs; and the less-than-or-equal-to and greater-than-or-equal-to
glyphs:
Notes:
- Due to a bug in TrueEdit, the sequences "=>" and "=<" do not work:
only ">=" and "<=" will produce a greater-than-or-equal-to or
less-than-or-equal-to glyph.
Exponent
- Glyphs:
- Caret; digits, decimal points, brackets, plus, minus, etc.; superior
digits, decimal points, brackets etc.
- Effect:
- Takes digits immediately following a ^ and changes them into their
superior forms. The ^ character itself is not displayed.
- Editor:
- A unique contextual editor with live areas for Caret, Digits and
Superiors.
The Caret area takes only one glyph: that of the caret or exponent
sign (^). The Digits live area should hold the digit glyphs, including
any sign, bracket or decimal glyphs - don't forget that a comma
is used in most of Europe as a decimal point. The third area,
Superiors, should contain the superior forms of the glyphs in
the Digits area (you can use the same superior numbers for both
upper and lower case digits if the font doesn't contain uppper
and lowercase superiors).
- Notes:
- Exponents end at 8 glyphs, or when they stop being digits (as
defined in the Digits column of the editor). In theory, you could
have alphabetic exponents, but that could easily interfere with
normal typing. If you must do it that way, be careful.
The Apple Fonts Group (applefonts@apple.com)
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