Professional Typography Expert 2/Professional Typography Expert 2.iso/fonttools/fontdict/_fontdict/manual

Text File | 1998-01-27 | 19.0 KB | 525 lines

Dr Fonty's Dictionary & Glossary of terms

                  Containing seventy definitions of
                        font related terminology

                         Designed to be used in
                     conjunction with the Dr Fonty
                              on-line manual

                         © iSV Products 1998

Accent
Defined by Collins as “a mark over a letter to show how
it is pronounced.” However note that accents can be
either above, below or to one side of a letter
depending on their type. For Example Å, È, Ç.

ASCII code
American Standard Code for Information Interchange.
Each letter in a font has an ASCII number. Very
simply, when a key is pressed on your keyboard an
ASCII code is sent to the computer, the computer then
displays the correct shape of character for that
code on the screen.

Ascender
Any part of a lower case letter that extends above
the x-height. The upper stroke on a lower case h or
b etc. The ascender on a font may be slightly higher
than the Cap-Height which is the height of Capital
letters such as “A”.

Base 0 (zero)
Base 0 fonts (such as Homerton & Trinity) contain
all of the Latin 1/2/3/4 encodings in 1 extra large
font. FontFiend can load these fonts and convert
them to any encoding. Note that some font suppliers
supply fonts in Base 0 format, but with only the
Latin1 letters defined. Base 0 fonts can easily be
identified by having a 0 on the end of the Outlines
file. For example
Resources:$.Fonts.Homerton.Medium.Outlines0.

Base line
An imaginary line that letters sit on. In fact very
few letters actually sit on this line. Round
characters such as “c” and “o” sit slightly below the
base line and above the x-height as round shapes
look visually smaller.

Bezier
A bezier is a mathematical description of a curve.
Outline fonts use bezier curves to describe letter
shapes, in a very similar way to Draw files. Bezier
curves consist of a start and end point and two
control points that alter the curve that joins the
start and end.

Bitmap font
The shapes of the letters in bitmap fonts are
actually small pictures made of pixels (sprites).
When enlarged or reduced they distort and the
pixels begin to show. When the  Outline font manager
displays a font it basically draws a  sprite of
each letter on screen in turn.

Blackletter
A typeface which has the appearance of being created
with a thick angled pen nib. Blackletter fonts are
often wrongly termed Gothic or Old English. The first
typeface set by John Guttenburg, one of the earliest
designers of movable metal type, was a Blackletter
face.

Body copy
The main part of a page of text, not headings or
captions. The “Base Style” in Impression should
really be called the Body Style as it affects all
of the text that does not have a different style
applied.

Bold
Font attribute denoting the thickness of the strokes
that make the characters. There is no definitive
measure of boldness or lightness, one typeface’s bold
may be lighter than another’s Regular. The designer
of the typeface decides how bold his bold is. Other
similar attributes are extra light, light, book,
regular, demi bold, ultra bold, heavy, black e.t.c.

Bounding Boxes
A bounding box literally defines the furthest parts of a
character, it is the smallest possible rectangular box that
can enclose the entire character. Bounding boxes are
very important, if a font has faulty bounding boxes it will
become very unreliable and cause “Font Cache Full”
errors. Bounding boxes are stored in the file “Outlines”
and optionally in the file called “Intmetrics”.

Bounding Boxes (Global)
A font also has a global bounding box, this is a box that
can enclose any character in the font. You may
sometimes find a font that works correctly for normal
letters, but parts of the accents over accented letters do
not get rendered correctly. This is because the fonts
global bounding box is not big enough to enclose
accented letters. You can recalculate the global bounding
box from the Dr Fonty global bounding box dialogue box.

Bullet
Large or bold dot • used for emphasizing or
separating points in a list. Not to be confused with
a period centered · which is a decimal point,
although it is often used as a small bullet.

Cap height
The height capital letters extend up to from the base
line. Some letters, for example rounded ones or
sharply pointed ones, extend above this. Lower case
letters such as “h” may extend above the cap height.

Character
A single letter in a font. Not just the normal A-Z
and letters but also symbols such as Ð. Some fonts,
such as Dingbats, contain only symbols as characters.
Characters contains outlines, skeletons, composites
and scaffolds.

Character Set (Encoding)
A character set is the entire list of letters and or
symbols available in a font. Most Acorn fonts have a
Latin 1 character set. The character sets are
designed by the International Standards Organization
for Acorn machines and by Microsoft for Windows
running on an IBM computer.

Composites
Composite characters are characters that are made
up of copies of the outlines from other characters.
For example an accented letter such as ñ (ntilde) will
be made up of two composite characters (n & tilde).
Any change made to the outline of a character will
effect any other characters that use the character as
a composite. e.g. changing n will alter  ñ.

Condensed
Style attribute of a font: Decker Condensed for
example. Condensed characters cannot normally be
automatically made by a computer. Condensed typefaces
have to be redesigned, otherwise they only appear
“squashed”. Dr Fonty's Alter  weight dialogue can
solve this problem by altering stroke widths in
one direction.

Control Points
These are the points that join up the outlines.
Acorn fonts have a slightly different format for the control
points than PostScript fonts. Acorn format control points
can be located at 45 or 90 degrees, where as PostScript
requires the control points to be at 90 degrees. These
control points are very similar to those used by !Draw
for vector artwork (See Outlines).

Cursive font
A font with a hand written appearance. This name is
also applied to fonts that have no upper case letters,
often also referred to as “Celtic” fonts.

Descender
Any part of a letter that extends below the base
line. The “tail” on a lower case g or q etc.

Dingbat
Small pictogram used as a bullet or other type of
attention grabbing device or indicator. Some fonts
contain only symbols and no letters. Examples
include ITC Zapfs Dingbats designed by Herman Zapf.

Decorative faces
Typefaces designed to be used only in small amounts
at quite large sizes. Typically these will have only
capital letters and are quite difficult to read when
used for body copy.

Design size
The x,y position of control points in Acorn fonts are
stored as numbers in the range -2048 to +2048. The
design size of the font is the number of these units that
occupy 1 em. A font with a design size of 1000 has
1000 units (possible positions) per em. 1000 is the
design size recommended for quality fonts.

Em dash
A dash, not a hyphen, as long as the point size
of the typeface. See em

Em or em space(Unit of measurement)
Usually a space or gap in text the length of which
is the same as the point size. For example, if you
are setting 36pt text and have instructions to indent
the first line of a paragraph by 1em, then the line
should be indented by 36 points.

En(Unit of measurement)
Half an em. If the typeface is set at 36 point then
1 Em would be 36 points and an En would be 18 points.

En dash
A dash, not hyphen, half as long as the point size
of the typeface. See en

Encoding
An encoding is a text file which lists all the
letters that are in a font and what ASCII numbers
they have. Most fonts have a Latin1 encoding, they
have all the letters required to type in western
European languages. Fonts with a Latin 2 encoding
have the accented letters required for eastern
European languages (such as Polish).

Extended
Style attribute of a font. Decker Extended for
example. Dr Fonty can make extended fonts using
a combination of the Transformation editor and the
Alter weight dialogue box. (See Condensed)

Fixed pitch font
A font in which every character takes up the same
amount of horizontal space like characters made by a
typewriter. These fonts are also referred to as
mono-spaced since each letter takes up the same
horizontal space.
Examples include Courier (Corpus).

Font
A Single typeface for example Trinity Italic.
Many people say a font when they actually mean a
Font Family. The font Trinity.Italic is actually
one weight from the Trinity type face family.

Fontitis
An affliction from which inexperienced DTP operators
suffer. Symptoms include many different typefaces in
lots of sizes and weights on the same page,
everything set in upper case, and lots of shadows,
auto-expanded, auto-condensed and other generally
distorted text.

Global scaffolds
Scaffolds can relate to a single character or to a range
of characters. For example you could have a global
scaffold across the top of all upper case letters to ensure
that they have the same cap-height when rendered at small
sizes. This scaffold would be defined in one upper case
character and a copy if it appear in all the others.
Dr Fonty renders global scaffolds as dark green.

Gothic
Font attribute meaning the font is sans serif.
Usually  used where there is a sans serif version of
a serif face, Clear Gothic, for example.
Often incorrectly used to describe Blackletter fonts.

Hinting
Extra information coded into all quality fonts which
ensures the characters remain symmetrical and
correctly shaped when displayed on screen or printed.
Hinting also ensures that fine parts of letters do
not disappear when their size is reduced so much that
these parts become less than one pixel thick. This is
very important for resolutions below 1200 dpi.
(See Scaffolds and Skeletons)

Italic
Font attribute. The italic version of a font is
angled usually by between 5 and 20 degrees off the
perpendicular. The characters are also redesigned to
appear more cursive. Italic characters cannot be
automatically made by any computer or programmer.
See Oblique.

Kerning
Kerning is stored in the “Intmetrics” part of a font.
Kerning is the adjustment of gaps between letters. It
allows the computer to alter the width of a letter depending
on the next letter to be printed. Kerning is defined as a pair
of characters and an adjustment value. If these two characters
appear next to each other the gap between them is adjusted.
Only Acorn Risc OS 3 (Version 8) fonts have kerning data,
Risc OS 2 (Version 6) fonts do not.

Leading (Pronounced Led-ing)
Extra space added between lines of text. Printers
used to do this by placing strips of lead between
lines of letters. This is sometimes also known as
line spacing but leading is the correct term.

Left side bearing (LSB)
The offset of the left side of each character from
the position (0,0). Some fonts have no left side
bearing, script fonts often have a left side bearing
defined in each character.

Ligatures
Two or more letters designed as a single entity,
f and i for example are designed as a single
character (fi) in which the dot over the i is often
removed. Not to be confused with diphthongs which
are actually letters in their own right.

Linear linking
This is a specialized form of linking. In the character E,
for example, the centre scaffold would be linked between
the top and bottom scaffold. This means that the position
of the centre of the E will always remain the same in
relation to the top and bottom of the character at any size.

Non-ranging or Oldstyle numerals
Numbers that have x-height, ascenders and descenders,
these are sometime called lower case numerals.

Oblique
Font attribute. The Oblique version of a font is
angled usually by 5 and 20 degrees off the
perpendicular. Unlike an Italic font none of the
characters are re-designed.

Outline font
The shapes of the letters in outline fonts are
described by bezier curves and so can be scaled
to any size without any loss of shape or accuracy.
Most modern computers use Outline fonts since they
can be used at any size. Hinting ensures that at
small sizes the font is not corrupted when
displayed on screen. (See Outlines)

Outlines
These are the letter shapes that you actually see
when a font is rendered. They are very similar to draw
files. They are scaled up and down to the right size to
plot the font correctly at a given point size.
Outlines consist of a set of points linked together by
straight lines, curves or moves.

Pica
12 points or 1/6th of an inch. This is sometimes
called  a pica em, and should not be confused
with an em or em space.

Pixel
Picture Element. A single dot many of which are
used to display a picture. The fonts displayed on
any monitor are composed of pixels - even if they
are outline fonts because a monitor can only
display pixels.

Point
1/72nd of an inch. If type is set at 72 point one
would  imagine that the text would be one inch high,
this is not the case.
See the entry Point Size for an explanation.

Point size
The size of the letters used to set the text. This
is complicated by the fact that in the days of metal
type the point size referred to the “height” of the
piece of metal the character is stuck to. Today there
is no such piece of metal, so to the casual observer
point sizes of typefaces appear to be arbitrary, and
differ considerably from face to face. The designer
of the typeface decides how much space there should
be between lines of text if no leading is added.

Proportional spaced font
Font in which all the letters have different
horizontal widths, for example an I will take up
less horizontal space than an M.

Sans serif typeface
A typeface in which the letters have no serifs,
Helvetica (Homerton), for example.

Scaffolds
Scaffolds are often referred to as hinting. Scaffolds
adjust the outlines of the character so that they
always sit neatly on a pixel grid, if part of the letter
goes below one pixel it will be adjusted so that it is
exactly one pixel. Control points in both outlines
and skeletons are attached to scaffolds.
(See Wide links & Tangent links).

Scaffold connections
Scaffolds are linked to the control points that make
up the outlines of a character. A scaffold can only
work if it is connected to the right control points.
When you click on a scaffold in Dr Fonty any points
connected to it will light up red.

Scaffold trees
A scaffold tree defines the way that global scaffolds
are linked together inside a font. A scaffold may be
defined in one character only, but appear in many
others. If you delete the original scaffold then the tree
will be corrupted and the font will no longer work.
Global scaffolds propagate through the font in specific
ways. If you look at a plan of this it looks as though the
letters have grown like leaves on a tree.

Scaffolds (X & Y)
Scaffolds can be placed either horizontally or vertically.
Those that are placed across the letter are the X
scaffolds (since they move in the X axis). This may initially
be confusing but with time will make sense. For example
the scaffold across the centre stroke of an H is a Y
scaffold, since it can move up or down (in the Y axis).
The scaffolds that attach to the two vertical strokes of the
H are X scaffolds since they can move left or right
(in the X axis).

Serif
Short terminating lines at the ends of letter
strokes. Trinity is a serif font whereas Homerton
is a sans-serif font (ie it has no serifs).

Serif typeface
A typeface in which the letters have serifs, Times,
for example. The design of serif faces has changed
over the years. Originally a serif face would have
been closer to hand-writing in style. More modern
fonts have an engraved type serif which is vertical.
Modern serif faces first appeared in Venice in the
late 15th century.

Shilling fraction
A fraction in which the numerator and denominator
do not sit directly above and below one another
e.g. ¾ or ½. (See stacked fraction).

Skeletons
Skeletons are drawn inside or around the Outlines
to prevent any part of the character “dropping-out”
at small sizes. They are usually placed inside parts
of the outlines that are quite thin. Skeletons are
always rendered even if parts of an outline are missed
by the font manager. PostScript fonts do not need
skeletons to prevent drop outs.

Small Caps
Capital letters designed to have the same or very
slightly larger size than the font’s x-height, but
which have the same weight. Dr Fonty can generate
small caps automatically. You may need to manually
alter the weight of small caps generated by
Dr Fonty using Alter weight.

Smart quotes
Single or double quotation marks which have correct
opening (or left hand or 66) and closing (or right
hand or 99) shapes. Many people incorrectly use the
symbols for feet and inches ( ' and " ) instead.

Stacked fraction
A fraction in which the numerator and denominator sit
directly above and below one another.
See shilling fraction.

Swash letter
A letter with elaborate flowing tails and curves.
Swash caps are often used to add decoration.

Tangent links
These are designed to prevent unsightly “pips” at the
edges of round characters. They are usually used on
characters like O or C. Unlike wide links they only
consist of one line.

Typeface or Typeface Family
A group of fonts with the same name: Times,
Times Italic, Times Bold, etc.

Wide links (scaffolds)
Wide links are designed to scaffold rectangular parts of
a fonts outlines, for example one side of an H character.
Wide links can either be horizontal or vertical, there are
however a couple of restrictions on their use. They can
only be a maximum of 253 design units in width, this
can make scaffolding some fonts very tricky.

Width
The widths specify how far the cursor, or caret,
should move after a letter has been printed. If
the width of a letter is not great enough then the
next character printed will overlap. If the width is
too great the next character will be too far away.
Dr Fonty can set widths automatically.

Winding rule (Even Odd)
An Even odd winding rule means that paths that should
be filled go in an anti-clockwise direction
(e.g. outside of “O”). Paths that should not be filled go
in a clockwise direction (e.g. inside of “O”). If you
were to walk around the edge of the paths of the
character the filled area would always be on your left.
PostScript fonts should have an even odd winding rule.
Acorn fonts have an even-odd or non zero winding rules.

Winding rule (Non Zero)
Non zero winding works like this, asign each path a value
+1 for anti-clockwise, and -1 for clockwise. Working from
the centre of the letter adding up the total for each
line that gets crossed. If the total is not zero then the
character should be filled. If you use a Non Zero winding
rule you may find that the centre of some letters get
filled in (e.g. “o”).

Weight
The weight of a typeface is its overall appearance
of light or black. A bold or heavy font appears
darker because the character’s strokes are thicker
and less of the white page can show through.

x-height
The size of lower case letters without ascenders or
descenders, most of the time this is actually the
size of the lower case x.