A |
- Abjad
-
Abjad is the technical term for the type of writing
system used by Semitic languages (Hebrew, Arabic,
etc.), where there are glyphs for all the consonants
but the reader must be prepared to guess what vowel
to add between two consonants.
Both Hebrew and Arabic have optional vowel marks
and are called "impure" abjads. Ancient Phoenician
had nothing but consonants and is a "pure" abjad.
See Also: alphabet,
abugida, syllabary and the relevant Wikipedia
article.
- Abugida
-
An abugida is somewhere in between an alphabet and a syllabary. The Indic writing systems
are probably the best known abugidas.
In most abugidas there are independant glyphs for
the consonants, and each consonant is implicitly
followed by a default vowel sound. All vowels other
than the default will be marked by either diacritics
or some other modification to the base consonant.
An abugida differs from a syllabary in that there
is a common theme to the the images representing a
syllable beginning with a given consonant (that is,
the glyph for the consonant), while in a syllabary
each syllable is distinct even if two start with a
common consonant.
An abugida differs from an abjad in that vowels
(other than the default) must be marked in the
abugida.
See Also: alphabet,
abjad, syllabary and the relevant Wikipedia
article.
Advance Width
- The distance between the start of this glyph and
the start of the next glyph. Sometimes called the
glyph's width. See also Vertical Advance
Width.
- Alphabet
-
A writing system where there are glyphs for all
phonemes -- consonants and vowels alike -- and (in
theory anyway) all phonemes in a word will be marked
by an appropriate glyph.
See Also: abjad, abugida, syllabary and the relevant Wikipedia
article.
- Apple Advanced
Typography
- Apple's extension to basic TrueType fonts. Includes
contextual substitutions, ligatures, kerning, etc. Also
includes distortable
fonts.
- Ascender
- A stem on a lower case letter which extends above
the x-height. "l" has an ascender.
See also X-height, Cap-height, Descender, Overshoot, Baseline
- Anchor Class
- Used to specify mark-to-base and cursive GPOS
subtables. See overview.
- Ascent
-
In traditional typography the ascent of a font was
the distance from the top of a block of type to the
baseline.
Its precise meaning in modern typography seems to
vary with different definers.
- ATSUI
- Apple's advanced typographical system. Also called
Apple Advanced Typography.
|
B |
- Baseline
- The baseline
is the horizontal line on which the (latin, greek,
cyrillic) letters sit. The baseline will probably be in
a different place for different scripts. In Indic
scripts most letters descend below the baseline. In CJK
scripts there is also a vertical baseline usually in
the middle of the glyph. The BASE and bsln tables allow you to
specify how the baselines of different scripts should
be aligned with respect to each other.
See also X-height, Cap-height, Ascender, Descender, Overshoot
- Bézier curve or
Bézier splines
- Bézier curves are described in detail in the
Bézier section of the main
manual.
- Bidi
-
He looked thoughtful and grave- but the
orders he gave
Were enough to bewilder the crew.
When he cried `Steer to starboard, but keep
her head larboard!'
What on earth was the helmsman to do?
The Hunting of the
Snark
Lewis Carroll
|
Bi-Directional text. That is a section of text
which contains both left-to-right and right-to-left
scripts. English text quoting Arabic, for example.
Things get even more complex with nested quotations.
The Unicode standard contains
an algorithm for laying out Bidi text. See also:
Boustrophedon.
- Black
letter
- Any of various type families based on medieval
handwriting.
See also gothic.
- BMP (Basic Multilingual
Plane)
-
The first 65536 code points of Unicode. These contain most of the
ordinary characters in the modern world. See Also
- SMP -- Supplementary
Multilingual Plane (0x10000-0x1FFFF)
- SIP -- Supplementary
Ideographic Plane (0x20000-0x2FFFF)
- SSP -- Supplementary
Special-purpose Plane (0xE0000-0xEFFFF)
- Bold
- A common font style. The stems
of the glyphs are wider than in the normal font, giving
the letters a darker impression. Bold is one of the few
LGC styles that translate readily to
other scripts.
- Bopomofo
- A (modern~1911) Chinese (Mandarin) alphabet used to provide
phonetic transliteration of Han ideographs in
dictionaries.
Boustrophedon
- Writing "as the ox plows", that is alternating
between left to right and right to left writing
directions. Early alphabets (Old Canaanite, and the
very early greek writings (and, surprisingly, fuþark)) used this. Often the right to
left glyphs would be mirrors of the left to right ones.
As far as I know, no modern writing system uses this
method (nor does OpenType have any support for it). See
Also Bidi.
|
C |
- Cap-height

- The height of a capital letter above the baseline
(a letter with a flat top like "I" as opposed to one
with a curved one like "O").
See also X-height, Ascender, Descender, Overshoot, Baseline
- CFF
- Compact Font Format most commonly used within
OpenType
postscript fonts, but is a valid font format even
without a SFNT wrapper. This is the
native font format for fonts with PostScript Type2
charstrings.
- Character
- A character is a Platonic ideal reified into at
least one glyph. For example the
letter "s" is a character which is reified into several
different glyphs: "S", "s", "s", long-s, etc.
Note that these glyphs can look fairly different from
each other, however although the glyph for an integral
sign might be the same as the long-s glyph, these are
in fact different characters.
- Character set
- A character set is an unordered set of characters
- CID
- Character Identifier, a number. In some CJK PostScript fonts the glyphs are not
named but are refered to by a CID number.
- CID-keyed font
- A PostScript font in
which the glyphs are index by CID and not by name.
- CJK
-
Chinese, Japanese, Korean. These three languages
require fonts with a huge number of glyphs. All three
share a writing system based on Chinese ideographs
(though they have undergone separate evolution in
each country, indeed mainland Chinese fonts are
different from those used in Taiwan and Hong Kong).
Japanese and Korean also have phonetic
syllabaries. The Japanese have two syllabaries,
Hiragana and katakana which have about 60 syllables.
The Koreans have one syllabary, hangul with tens of
thousands of syllables.
- CJKV
- Chinese, Japanese, Korean, Vietnamese. These four
languages require fonts with a huge number of
glyphs.
- Condensed
- A condensed font is one where the space between the
stems of the glyphs, and the distance between glyphs
themselves has been reduced.
- Conflicting hints
- If a glyph contains two hints where the start or
end point of one is within the range of the other then
these hints conflict. They may not be active
simultaneously.
|
D |
- Descender
- A stem on a lower case letter which extends below
the baseline. "p" has a descender.
See also X-height, Cap-height, Ascender, Overshoot, Baseline
- Descent
-
In traditional typography the descent of a font was
the distance from the bottom of a block of type to
the baseline.
Its precise meaning in modern typography seems to
vary with different definers.
- Device Table
- A concept in OpenType which allows you to enter
spacing adjustments geared to rasterization at
particular pixel sizes. If a kerning value that works
most of the time leads to an ugly juxtaposition of
glyphs on a 12 pixel high font, then you can add a
special tweak to the spacing that only is applicable at
12 pixels (and another one at 14 and 18, or whatever is
needed). Similar functionality is needed for anchored
marks.
- Didot point
- The European point. 62
2/3 points per 23.566mm (
2.66pt/mm or 67.55pt/inch ). There is also a "metric"
didiot point: .4mm.
- Distortable font
- See Multi-Master
|
E |
- em
-
A linear unit equal to the point size of the font. In
a 10 point font, the em will be 10 points. An
em-space is white-space that is as wide as the point
size. An em-dash is a horizontal bar that is as wide
as the point size.
An em-square is a square one em to each side. In
traditional typography (when each letter was cast in
metal) the glyph had to be drawn within the
em-square.
- em unit
- In a scalable font the "em" is subdivided into
units. In a postscript font there are usually 1000
units to the em. In a TrueType font there might be 512,
1024 or 2048 units to the em. In an Ikarus font there
are 15,000 units. FontForge uses these units as the
basis of its coordinate system.
- en
- One half of an "em"
- Encoding
-
An encoding is a mapping from a set of bytes onto a
character
set. It is what determines which byte sequence
represents which character. The words "encoding" and
"character set" are often used synonymously. The
specification for ASCII specifies both a character
set and an encoding. But CJK character sets often
have multiple encodings for the character set (and
multiple character sets for some encodings).
In more complicated cases it is possible to have
multiple glyphs associated with each character (as in
arabic where most characters have at least 4
different glyphs) and the client program must pick
the appropriate glyph for the character in the
current context.
- Eth -- Edh
- The old germanic letter "ð" for the voiced
(English) "th" sound (the sound in "this" -- most
English speakers aren't even aware that "th" in English
has two sounds associated with it, but it does, see
also Thorn)
- Even-Odd Fill
rule
- To determine if a pixel should be filled using
this rule, draw a line from the pixel to infinity
(in any direction) then count the number of times
contours cross this line. If that number is odd then
fill the point, if it is even then do not fill the
point. This method is used for fonts by postscript
rasterizers after level 2.0 of PostScript. See Also
Non-Zero Winding Number
Fill.
- Extended
- An extended font is one where the space between the
stems of the glyphs, and the distance between glyphs
themselves has been increased.
- Extremum
- A point on a curve where the curve attains its
maximum or minimum value. On a continuous curve this
can happen at the endpoints (which is dull) or where
dx/dt=0 or dy/dt=0.
|
F |
- Features
(OpenType)
- When creating fonts for complex scripts (and even
for less complex scripts) various transformations (like
ligatures) must be applied to the input glyphs before
they are ready for display. These transformations are
identified as font features and are tagged with (in
OpenType) a 4 letter tag or (in Apple) a 2 number
identfier. The meanings of these features are
predefined by MicroSoft and Apple. FontForge allows you
to tag each lookup with one or several features
when you create
it (or later).
- Feature File
- This is a text syntax designed by Adobe to describe
OpenType features. It can be used to move feature and
lookup information from one font to another.
- Feature/Settings (Apple)
- These are roughly equivalent to OpenType's Features above, they are
defined by Apple.
- Font
-
A collection of glyphs,
generally with at least one glyph associated with
each character in the font's character set, often with an
encoding.
A font contains much of the information needed to
turn a sequence of bytes into a set of pictures
representing the characters specified by those
bytes.
In traditional typesetting a font was a collection
of little blocks of metal each with a graven image of
a letter on it. Traditionally there was a different
font for each point-size.
- Font Family, or
just Family
- A collection of related fonts.
Often including plain, italic and bold styles.
- FontForge
- This.
- FreeType
- A library for rasterizing fonts. Used extensively
in FontForge to understand the behavior of truetype
fonts and to do better rasterization than FontForge
could unaided.
- Fractur
- The old black letter writing style used in Germany
up until world war II.
See also gothic.
- Fuþark (Futhark)
- The old germanic runic script
|
G |
- Ghost Hint
-
Sometimes it is important to indicate that a
horizontal edge is indeed horizontal. But the edge
has no corresponding edge with which to make a normal
stem. In this case a special hint is used with a width
of -20 (or -21). A ghost hint must lie entirely
within a glyph. If it is at the top of a contour use
a width of -20, if at the bottom use -21. Ghost hints
should also lie within BlueZones.
(The spec also mentions vertical ghost hints, but
as there are no vertical bluezones it is not clear
how these should be used).
- Glyph
-
A glyph is an image, often associated with one or
several characters. So the
glyph used to draw "f" is associated with the
character f, while the glyph for the "fi" ligature is
associated with both f and i. In simple latin fonts
the association is often one to one (there is exactly
one glyph for each character), while in more complex
fonts or scripts there may be several glyphs per
character (In renaissance printing the letter "s" had
two glyphs associated with it, one, the long-s, was
used initially and medially, the other, the short-s,
was used only at the end of words). And in the
ligatures one glyph is associated with two or more
characters.
Fonts are collections of
glyphs with some form of mapping from character to
glyph.
- Grid
Fitting
- Before TrueType glyphs are rasterized they go
through a process called grid fitting where a tiny
program (associated with each glyph) is run which moves
the points on the glyph's outlines around until they
fit the pixel grid better.
- Gothic
- The German monks at the time of Gutenberg used a
black-letter writing style, and he copied their
handwriting in his typefaces for printing. Italian type
designers (after printing spread south) sneered at the
style, preferring the type designs left by the Romans.
As a term of contempt they used the word gothic, the
style of the goths who helped destroy the roman
empire.
- Graphite tables
-
Graphite
is an extension to TrueType which embeds several
tables into a font containing rules for contextual
shaping, ligatures, reordering, split glyphs,
bidirectionality, stacking diacritics, complex
positioning, etc.
This sounds rather like OpenType -- except that
OpenType depends on the text layout routines knowing
a lot about the glyphs involved. This means that
OpenType fonts cannot be designed for a new language
or script without shipping a new version of the
operating system. Whereas Graphite tables contain all
that hidden information.
Apple's Advanced Typography provides a better
comparison, but Graphite tables are supposed to be
easier to build.
SIL International provides a free
Graphite compiler .
- Grotesque
- See also sans-serif.
|
H |
- Han characters
- The ideographic characters used in China, Japan and Korea (and, I believe, in
various other asian countries as well (Vietnam?)), all
based on the writing style that evolved in China.
- Hangul
- The Korean syllabary. The only
syllabary (that I'm aware of anway) based on an
alphabet -- the letters of the alphabet never appear
alone, but only as groups of two or three making up a
syllable.
- Hanja
- The Korean name for the Han characters
- Hints
- These are described in detail in the main manual. They help
the rasterizer to draw a glyph
well at small pointsizes.
- Hint Masks
- At any given point on a contour hints may not conflict. However
different points in a glyph may need conflicting hints.
So every now and then a contour will change which hints
are active. Each list of active hints is called a hint
mask.
- Hiragana
- One of the two Japanese syllabaries. Both Hiragana
and Katakana have
the same sounds.
|
I |
- Ideographic character
- A single character which represents a concept
without spelling it out. Generally used to mean Han
(Chinese) characters.
- Italic
-
A slanted style of a font,
generally used for emphasis.
Italic differs from Oblique
in that the transformation from the plain to the
slanted form involves more than just skewing the
letterforms. Generally the lower-case a changes to
a, the serifs on lower-case letters like i
(i) change, and the font generally gains a
freer look to it.
|
J |
- Jamo
- The letters of the Korean alphabet. These are
almost never seen alone, generally appearing in groups
of three as part of a Hangul syllable. The Jamo
are divided into three categories (with considerable
overlap between the first and third), the choseong --
initial consonants, the jungseong -- medial vowels, and
the jongseong -- final consonants. A syllable is
composed by placing a choseong glyph in the upper left
of an em-square, a jungseong in the upper right, and
optionally a jongseong in the lower portion of the
square.
|
K |
- Kanji
- The Japanese name for the Han characters.
- Katakana
- One of the two (modern) Japanese syllabaries. Both
Hiragana and
Katakana have the same sounds.
- Kerning
-
When the default spacing between two
glyphs is inappropriate the font may include extra
information to indicate that when a given glyph (say
"T") is followed by another glyph (say "o") then the
advance width of the "T" should be adjusted by a
certain amount to make for a more pleasing display.
In the days of metal type, metal actually had to
be shaved off the slug of type to provide a snugger
fit. In the image on the side, the "F" on the left
has had some metal removed so that a lower case
letter could snuggle closer to it.
- Kern
pair
- A pair of glyphs for which kerning information has been
specified.
- Kerning by classes
- The glyphs of the font are divided into classes of
glyphs and there is a large table which specifies
kerning for every possible combination of classes.
Generally this will be smaller than the equivalent set
of kerning pairs because each class will usually
contain several glyphs.
- Knuth, Donald
- A mathematician who got so fed up with bad
typesetting back in the 1970&80s that he created
his own font design system and typographical layout
program called, respectively, MetaFont and TeX.
|
L |
Left side
bearing
- The horizontal distance from a glyph's origin to
its leftmost extent. This may be negative or
positive.
- Lemur
-
A monotypic genus of prosimian primates,
now found only on Madagascar but formally (about 50
million years ago) members of this family were much
more wide spread.
- Ligature
- A single glyph which is composed of two adjacent
glyphs. A common example in the latin script is the
"fi" ligature
which has a nicer feel to it than the
sequence .
- LGC
- Latin, Greek, Cyrillic. These three alphabets have
evolved side by side over the last few thousand years.
The letter forms are very similar (and some letters are
shared). Many concepts such as "lower case", "italic"
are applicable to these three alphabets and not to any
others. (OK, Armenian also has lower case
letters).
|
M |
- Manyogana
- An early Japanese script, ancestral to both
hiragana and katakana. Manyogana
used kanji for their
phontic sounds, and over the years these kanji were
simplified into hiragana and katahana.
Metal Type
- Once upon a time, printing presses smashed plates
full of slugs of metal against paper.
- Monospace
- A font in which all glyphs have the same advance
width. These are sometimes called typewriter
fonts.
- Multi-layered fonts
-
(FontForge's own term) PostScript type3 fonts and SVG
fonts allow for more drawing possibilities than
normal fonts. Normal fonts may only be filled with a
single color inherited from the graphics environment.
These two fonts may be filled with several different
colors, stroked, include images, have gradient fills,
etc..
See Also
- Multiple
Master Font
-
A multiple master font is a PostScript font schema
which defines an infinite number of related fonts.
Multiple master fonts can vary along several axes,
for example you might have a multiple master which
defined both different weights and different widths
of a font family, it could be used to generate: Thin,
Normal, Semi-Bold, Bold, Condensed, Expanded,
Bold-Condensed, etc.
Adobe is no longer developing this format. Apple
has a format which acheives the same effect but has
not produced many examples. FontForge supports
both.
|
N |
- Namelist
- A mapping from unicode code point to glyph
name.
- Non-Zero
Winding Number Fill rule
- To determine if a pixel should be filled using this rule
draw a line from here to infinity (in any direction)
and count the number of times contours cross this line.
If the contour crosses the line in a clockwise
direction add 1, of the contour crosses in a counter
clockwise direction subtract one. If the result is
non-zero then fill the pixel. If it is zero leave it
blank. This method is used for rasterizing fonts by
truetype and older (before version 2) postscript.
See Also Even-Odd Fill
Rule
|
O |
- Ogham
- The old Celtic inscription script.
- OpenType
-
A type of font. It is an attempt to merge postscript
and truetype fonts into one specification.
An opentype font may contain either a truetype or
a postscript font inside it.
It contains many of the same data tables for
information like encodings that were present in
truetype fonts.
Confusingly it is also used to mean the advanced
typographic tables that Adobe and MicroSoft (but not
Apple) have added to TrueType. These include things
like contextual ligatures, contextual kerning, glyph
substitution, etc.
And MS Windows uses it to mean a font with a
'DSIG' (Digital Signature) table.
- OpenType Tables
- Each opentype font contains a collection of tables
each of which contains a certain kind of information.
See here for the tables
used by FontForge.
- Oblique
-
A slanted style of a font,
generally used for emphasis.
Oblique differs from Italic
in that the transformation from the plain to the
slanted form involves just skewing the
letterforms.
- Overshoot

- In order for the curved shape of the "O" to appear
to be the same height as the flat top of the "I" it
tends to "overshoot" the cap-height (or x-height), or
undershoot the baseline by about 3% of the cap-height
(or x-height). For a triangular shape (such as "A") the
overshoot is even greater, perhaps 5%.
These guidelines are based on the way the eye works and
the optical illusions it generates and are taken from
Peter Karow's Digital Formats for Typefaces, p.
26).
The overshoot is also dependant on the point-size of a
font, the larger the point-size the smaller the
overshoot should be. Generally modern fonts will be
used at multiple point-sizes, but in some font families
there are multiple faces for the different point-sizes,
and in such a case the overshoot will probably vary
from face to face.
See also X-height, Cap-height, Ascender, Descender, Baseline
|
P |
- Panose
-
A system for describing fonts. See HP's PANOSE classification
metrics guide, AGFA's PANOSE
classification metrics guide and MicroSoft's
PANOSE classification in Windows. There is also
an extension called Panose
2.
FontForge only knows about the classification
scheme for Latin fonts. Other schemes exist for other
scripts.
- PfaEdit
- This was the early name for FontForge. The original
conception was that it would only edit type1 ASCII
fonts (hence the name), it quickly metamorphosed beyond
that point, but it took me three years to rename
it.
- Phantom points
- In a truetype font there are a few points added to
each glyph which are not specified by the contours that
make up the glyph. These are called phantom points. One
of these points represents the left side bearing, and
the other the advance width of the glyph. Truetype
instructions (hints) are allowed to move these points
around just as any other points may be moved -- thus
changing the left-side-bearing or the advance width.
Early versions of TrueType supplied just these two
phantoms, more
recent versions also supply a phantom for the top
sidebearing and a phantom for the vertical advance
width.
- Pica
-
A unit of length defined (in the US at least) to be
35/83cm (or approximately 1/6th of an inch). This was
used for measuring the length of lines of text (as
"30 picas and 4 points long"), but not for measuring
font heights.
In Renaissance typography, before there were
points, sizes of type had names, and "pica" was used
in this context. As: "Great Canon", "Double Pica",
"Great Primer", "English", "Pica", "Primer", "Small
Pica", "Brevier", "Nonpareil" and "Pearl" (each name
representing a progressively smaller size of type).
and See Caslon's
type specimen sheet on Wikipedia.
- Pica point
- The Anglo-American point. With
72.27 points per inch ( 2.85pt /mm ).
- Point
-
A point is a unit of measurement. There were three
(at least) different definitions for "point" in
common usage before the advent of computers. The one
in use in the Anglo-Saxon printing world was the
"pica point" with 72.27 points per inch ( 2.85pt /mm
), while the one used in continental Europe was the
didot point with 62 2/3
points per 23.566mm ( 2.66pt/mm or 67.54pt/inch ) and
the French sometimes used the Mediaan point (72.78
points per inch, 2.86pt/mm).
The didiot and pica points were so arranged that
text at a given point-size would have approximately
the same cap-height in both
systems, the didot point would have extra white-space
above the capitals to contain the accents present in
most non-English Latin based scripts.
This has the interesting side effect that a font
designed for European usage should have a smaller
proportion of the vertical em given over to the text
body. I believe that computer fonts tend to ignore
this, so presumably european printers now set with
more leading.
As far as I can tell, computers tend to work in
approximations to pica points (but this may be
because I am in the US), PostScript uses a unit of
1/72nd of an inch.
Originally fonts were not described by point size,
but by name. It was
not until the 1730s that Pierre Fournier that created
the point system for specifying font heights. This
was later improved upon by François Didiot (whence
the name of the point). In 1878 the Chicago Type
Foundry first used a point system in the US. In 1886
the US point was standardized -- the pica was defined
to be 35/83cm, and the pica point defined to be
1/12th of that.
- Point
Size
- In traditional typography a 10pt font was one where
the block of metal for each glyph was 10 points high.
The point size of a font is the unleaded baseline to
baseline distance.
- Point of inflection
-
A point on a curve where it changes from being
concave downwards to concave upwards (or vice versa).
Or in mathematical terms (for continuous curves)
where d2 y/dx2=0 or infinity.
Cubic splines may contain inflection points,
quadratic splines may not.
- PostScript
-
PostScript is a page-layout language used by many
printers. The language contains the specifications of
several different font formats. The main (FontForge)
manual has a section describing how PostScript differs from
TrueType.
- Type 1 -- This is the old standard for
PostScript fonts. Such a font generally has the
extension .pfb (or .pfa). A type 1 font is limited
to a one byte encoding (ie. only 256 glyphs may be
encoded).
- Type 2/CFF -- This is the format used within
OpenType fonts. It is
almost the same as Type 1, but has a few extensions
and a more compact format. It is usually inside a
CFF wrapper, which is usually inside an OpenType
font. The CFF font format again only allows a 1
byte encoding, but the OpenType wrapper extends
this to provide more complex encoding types.
- Type 3 -- This format allows full postscript
within the font, but it means that no hints are allowed, so these fonts will
not look as nice at small point-sizes. Also most
(screen) rasterizers are incapable of dealing with
them. A type 3 font is limited to a one byte
encoding (ie. only 256 glyphs may be encoded).
- Type 0 -- This format is used for collecting
many sub-fonts (of Type 1, 2 or 3) into one big
font with a multi-byte encoding, and was used for
CJK or Unicode fonts.
- Type 42 -- A TrueType
font wrapped up in PostScript. Sort of the opposite
from OpenType.
- CID -- This format is used for CJK fonts with
large numbers of glyphs. The glyphs themselves are
specified either as type1 or type2 glyph format.
The CID font itself has no encoding, just a mapping
from CID (a number) to glyph. An set of external
CMAP files are used to provide appropriate
encodings as needed.
|
Q |
|
R |
- Reference
- A reference
is a way of storing the outlines of one glyph in
another (for example in accented glyphs). Sometimes
called a "componant".
Right side
bearing
- The horizontal distance from a glyph's rightmost
extent to the glyph's advance width. This may be
positive or negative.
|
S |
- Sans
Serif
- See the section on serifs.
- Script
- A script is a
character set and associated rules for putting
characters together. Latin, arabic, katakana and hanja
are all scripts.
- Serif
-
latin
greek
cyrillic |
 |
 |
a serif |
sans serif |
hebrew |
 |
 |
bet serif |
sans serif |
-
Back two thousand years ago when the Romans were
carving their letters on stone monuments, they
discovered that they could reduce the chance of the
stone cracking by adding fine lines at the
terminations of the main stems of a glyph.
These fine lines were called serifs, and came to
have an esthetic appeal of their own. Early type
designers added them to their fonts for esthetic
rather than functional reasons.
At the end of the nineteenth and beginning of the
twentieth centuries, type-designers started designing
fonts without serifs. These were initially called
grotesques because their form appeared so strange,
they are now generally called sans-serif.
Other writing systems (Hebrew for one) have their
own serifs. Hebrew serifs are rather different from
latin (cyrillic, greek) serifs and I don't know their
history. Hebrew serifs only occur at the top of a
glyph
I would welcome examples from other scripts of
serifed and sans-serifed glyphs.
- SFD
-
SplineFont DataBase. These are FontForge's own
personal font representation. The files are ASCII and
vaguely readable, the format is described here. As of 14 May 2008 the
format has been registered with IANA for a MIME type:
application/vnd.font-fontforge-sfd.
Other people use sfd too. (Unfortunately)
- Tops-10, on the Digital PDP-10 used sfd to mean
"Sub File Directory". Tops-10 made a distinction
between top-level (home) directories, called "user
file directories", and sub-directories.
- TeX uses it to mean "Sub Font Definition" where
a TeX sfd file contains information on how to break
a big CJK or Unicode font up into small sub-fonts,
each with a 1 byte encoding which TeX (or older
versions of TeX) needed.
- Others...
- SFNT
- The name for the generic font format which contains
TrueType, OpenType, Apple's bitmap only, X11's bitmap
only, obsolete 'typ1' fonts and Adobe's SING fonts (and
no doubt others). The SFNT format describes how font
tables should be laid out within a file. Each of the
above formats follow this general idea but include more
specific requirements (such as what tables are needed,
and the format of each table).
- SIP
-
Supplementary Ideographic Plane (0x20000-0x2FFFF) of
unicode. Used for rare Han characters (most are no
longer in common use) See Also
- BMP -- Basic Multilingual
Plane (0x00000-0x0FFFF)
- SMP -- Supplementary
Multilingual Plane (0x10000-0x1FFFF)
- SSP -- Supplementary
Special-purpose Plane (0xE0000-0xEFFFF)
- SMP
-
Supplementary Multilingual Plane (0x10000-0x1FFFF) of
unicode. Used for ancient and artificial alphabets
and syllabaries -- like Linear B, Gothic, and
Shavian. See Also
- BMP -- Basic Multilingual
Plane (0x00000-0x0FFFF)
- SIP -- Supplementary
Ideographic Plane (0x20000-0x2FFFF)
- SSP -- Supplementary
Special-purpose Plane (0xE0000-0xEFFFF)
- Spline
- A curved line segment. See the section in the manual on
splines. The splines used in FontForge are all
second or third order Bézier
splines (quadratic or cubic), and Raph Levien's clothoid
splines.
- SSP
-
Supplementary Special-purpose Plane (0xE0000-0xEFFFF)
of unicode. Not used for much of anything. See Also
- BMP -- Basic Multilingual Plane
(0x00000-0x0FFFF)
- SMP -- Supplementary
Multilingual Plane (0x10000-0x1FFFF)
- SIP -- Supplementary
Ideographic Plane (0x20000-0x2FFFF)
- State machine
-
A state machine is like a very simple little program,
they are used on the mac for performing contextual
substitutions and kerning. The state machine
dialog is reachable from Element->Font Info->Lookups
The "state machine" consists of a table of states,
each state in turn consists of a series of potential
transitions (to the same or different states)
depending on the input. In state machines within
fonts, the machine starts out in a special state
called the start state, and reads the glyph stream of
the text. Each individual glyph will cause a state
transition to occur. As these transitions occur the
machine may also specify changes to the glyph stream
(conditional substitutions or kerning).
Example
- Strike
- A particular instance of a font. Most commonly a
bitmap strike is a particular pixelsize of a font.
- Style
-
There are various conventional variants of a font. In
probably any writing system the thickness of the
stems of the glyphs may be varied, this is called the
weight of a font. Common
weights are normal and bold.
In LGC alphabets an italic (or oblique) style has arisen and is used
for emphasis.
Fonts are often compressed into a condensed style, or expanded out
into an extended style.
Various other styles are in occasional use:
underline, overstrike, outline, shadow.
- SVG
- Scalable Vector Graphics. An XML format used for
drawing vector images. It includes a font format.
- Syllabary
-
A syllabary is a phonetic writing system like an
alphabet. Unlike an alphabet the sound-unit which is
written is a syllable rather than a phoneme. In
Japanese KataKana the sound "ka" is represented by
one glyph. Syllabaries tend to be bigger than
alphabets (Japanese KataKana requires about 60
different characters, while the Korean Hangul
requires tens of thousands).
See Also: abjad, abugida, alphabet and the relevant Wikipedia
article.
|
T |
- TeX
- A typesetting
package.
- Thorn
- The germanic letter "þ" used for the unvoiced
(English) "th" sound (as in the word "thorn"), I
believe this is approximately the same sound value as
Greek Theta. Currently a corrupt version of this glyph
survives as "ye" for "the". See also
Eth.
- True Type
-
A type of font invented by Apple and shared with
MicroSoft. It specifies outlines with second degree
(quadratic) Bézier curves,
contains innovative hinting controls, and an
expandable series of tables for containing whatever
additional information is deemed important to the
font.
Apple and Adobe/MicroSoft have expanded these
tables in different ways to include for advanced
typographic features needed for non-latin scripts (or
for complex latin scripts). See Apple Advanced Typography and
OpenType.
- TrueType Tables
- Each truetype font contains a collection of tables
each of which contains a certain kind of information.
See here for the tables
used by FontForge.
- Type 1
- A type of PostScript font
which see.
- Type 2
- A type of PostScript
font, used within OpenType font
wrappers.
- Type 3
- A very general type of PostScript font, which see.
- Type 0
- A type of PostScript
font, which see.
- Type High
- In the days of metal type this was the height of
the piece of metal -- the distance from the printing
surface to the platform on which it rested.
- Typewriter
- See Monospace.
|
U |
- Unicode
-
A character set/encoding which tries to contain all
the characters currently used in the world, and many
historical ones as well. See the Unicode consortium.
- BMP -- Basic Multilingual
Plane (0x00000-0x0FFFF)
- SMP -- Supplementary
Multilingual Plane (0x10000-0x1FFFF)
- SIP -- Supplementary
Ideographic Plane (0x20000-0x2FFFF)
- SSP -- Supplementary
Special-purpose Plane (0xE0000-0xEFFFF)
More
info.
- Undershoot
- See the explanation at Overshoot.
- UniqueID
- This is a field in a PostScript font, it was
formerly used as a mechanism for identifying fonts
uniquely, then Adobe decided it was not sufficient and
created the XUID (extended Unique ID) field. Adobe has
now decided that both are unneeded.
There is a very similar field in the TrueType 'name'
table.
- UseMyMetrics
- This is a truetype concept which forces the width
of an composite glyph (for example an accented letter)
to be the same as the width of one of its components
(for example the base letter being accented).
|
V |
- Vertical Advance Width
- CJK text is often written vertically (and sometimes
horizontally), so each CJK glyph has a vertical advance
as well as a horizontal
advance.
|
W |
- Weight
-
The weight of a font is how thick (dark) the stems of
the glyphs are. Traditionally weight is named, but
recently numbers have been applied to weights.
Thin |
100 |
Extra-Light |
200 |
Light |
300 |
Normal |
400 |
Medium |
500 |
Demi-Bold |
600 |
Bold |
700 |
Heavy |
800 |
Black |
900 |
Nord |
|
Ultra |
|
- Width
- This is a slightly ambiguous term and is sometimes
used to mean the advance
width (the distance from the start of this glyph to
the start of the next glyph), and sometimes used to
mean the distance from the left side bearing to the
right side bearing.
|
X |
- X-height

- The height of a lower case letter above the base
line (with a flat top like "x" or "z" or "v" as opposed
to one with a curved top like "o" or one with an
ascender like "l") .
See also Cap-height, Ascender, Descender, Overshoot, Baseline
- XUID
- Extended Unique ID in a PostScript font. Now
somewhat obsolete. See the explanation at Unique ID.
|
Y |
|
Z |
- Zapf, Hermann
- Outstanding modern font designer.
|