In typography, a font (also fount) is
traditionally defined as a complete character set of a single size and
style of a particular typeface. For example, the set of all characters
for 9-point Bulmer italic is a font, and the 10-point size would be a
separate font, as would the 9 point upright.
After the introduction of computer fonts based on fully scalable
outlines, a broader definition evolved. Font is no longer size-specific,
but still refers to a single style. Bulmer regular, Bulmer italic,
Bulmer bold and Bulmer bold italic are four fonts, but one typeface.
However, the term font is also often used as a metonym for typeface.
Contents
[hide]
* 1 Metal type
* 2 Font characteristics
o 2.1 Weight
o 2.2 Slope
o 2.3 Width
o 2.4 Optical size
o 2.5 Metrics
o 2.6 Serifs
o 2.7 Proportion
* 3 Etymology
* 4 References
[edit] Metal type
In a traditional manual printing (letterpress) house the font would
refer to a complete set of metal type that would be used to typeset an
entire page. Unlike a digital typeface it would not include a single
definition of each character, but commonly used characters (such as
vowels and periods) would have more physical type-pieces included. A
font when bought new would often be sold as (for example in a roman
alphabet) 12pt 14A 34a, meaning that it would be a size 12 point font
containing 14 uppercase 'A's, and 34 lowercase 'A's. The rest of the
characters would be provided in quantities appropriate for the
distribution of letters in that language. Some metal type required in
typesetting, such as dashes, spaces and line-height spacers, were not
part of a specific font, but were generic pieces which could be used
with any font.[1] Line spacing is still often called "leading," because
the strips used for line spacing were made of lead (rather than the
harder alloy used for other pieces).
In the 1880s–90s, "hot lead" typesetting was invented, in which type was
cast as it was set, either piece by piece (as in the Monotype
technology) or entire lines of type at a time (as in the Linotype
technology).
[edit] Font characteristics
Besides the character height when using the mechanical sense of the
term, there are several characteristics which may distinguish fonts,
also depending on the script(s) that the typeface supports. In European
alphabetic scripts, i.e. Latin, Cyrillic and Greek, the main such
properties are the stroke width, called weight, the style or angle and
the character width.
The regular or standard font is often labeled roman, both to distinguish
it from bold or thin and from italic or oblique. The keyword for the
default, regular case is often omitted for variants and never repeated,
otherwise it would be Bulmer regular italic, Bulmer bold regular and
even Bulmer regular regular.
Different fonts of the same face may be used in the same work for
various degrees and types of emphasis.
[edit] Weight
The weight of a particular font is the thickness of the character
outlines relative to their height.
Helvetica weights
A typeface may come in fonts of many weights, from ultra-light to
extra-bold or black; four to six weights are not unusual, and a few
typefaces have as many as a dozen. Many typefaces for office, Web and
non-professional use come with just a normal and a bold weight. If no
bold weight is provided, many renderers (browsers, word processors,
graphic and DTP programs) support faking a bolder font by rendering the
outline a second time at an offset, or just smearing it slightly at a
diagonal angle.
The base weight differs among typefaces; that means one normal font may
appear bolder than some other normal font. For example fonts intended to
be used in posters are often quite bold by default while fonts for long
runs of text are rather light. Therefore weight designations in font
names may differ in regard to the actual absolute stroke weight or
density of glyphs in the font.
Attempts to systematize a range of weights led to a numerical
classification first used by Adrian Frutiger with the Univers typeface,
although therein only ranging from 3 to 8. The TrueType font format
introduced a scale from 100 through 900, also used in CSS and OpenType.
The first algorithmic descrition of fonts was perhaps made by Donald
Knuth in his Metafont and TeX system of programs.
There are many names used to describe the weight of a font in its name,
differing among type foundries and designers, but their relative order
is usually fixed, something like this:
* thin
* ultra-light
* extra-light
* light
* book
* normal / regular / roman / plain
* medium
* demi / semi-bold
* bold
* extra-bold / extra
* heavy
* black
* extra-black
* ultra / ultra-black
The terms normal, regular and plain, sometimes also book, are being used
for the standard weight font of a typeface. Whether book is lighter or
heavier than regular is not entirely consistent across typefaces, though
"lighter" seems to be more common.
[edit] Slope
In today's European typefaces, especially roman ones, the font style is
usually connected to the angle. When the normal, roman or upright font
is slanted – usually to the right in left-to-right scripts – the
lowercase character shapes change slightly as well, approaching a more
handwritten, cursive style. In this italic type, character edges may
even connect and ligatures are more common. Although rarely encountered,
a typographic face may be accompanied by a matching calligraphic face,
which might be considered a further font style of one typeface.
Cyrillic italics
In many sans-serif and some serif typefaces the characters of the italic
fonts are only slanted (oblique), which is often done algorithmically,
without otherwise changing their appearance. On the other hand there are
typefaces with upright characters that take a more cursive form without
a change in angle. For example the Cyrillic minuscule ‘?’ may look like
a smaller form of its majuscule '?' or more like a roman small ‘m’ as in
its standard italic appearance; in this case the distinction between
styles is also a matter of local preference.
In Frutiger’s nomenclature the second digit for upright fonts is a 5,
for italic fonts a 6.
The two Japanese syllabaries, katakana and hiragana, could be seen as
two styles or typographic variants of each other, but usually are
considered separate character sets.
Cursive-only scripts such as Arabic also have different styles, in this
case for example Naskh and Kufic, although these often depend on
application, area or era.
There are other aspects that can differ among font styles, but more
often these are considered immanent features of the typeface. These
include the look of the minuscules, which may be smaller versions of the
capital letters (small caps) although the script has developed
characteristic shapes for them. Some typefaces do not include separate
glyphs for the cases at all, thereby abolishing the bicamerality. While
most use uppercase characters only, some labeled unicase exist which
choose either the majuscule or the minuscule glyph at a common height
for both characters.
[edit] Width
Some typefaces include fonts that vary the width of the characters
(stretch).
Narrower fonts are usually labeled compressed, condensed or narrow. In
Frutiger’s system, the second digit of condensed fonts is a 7. Wider
fonts may be called wide, extended or expanded. Both can be further
classified by prepending extra, ultra or the like.
These separate fonts have to be distinguished from techniques that alter
the letter-spacing to achieve narrower or smaller words, especially for
justified text alignment.
[edit] Optical size
Some professional digital typefaces include fonts that are optimised for
certain sizes. There are several naming schemes for such variant
designs. One such scheme, invented and popularized by Adobe Systems,
refers to the variant fonts by the applications those are typically used
for, with the exact point sizes intended varying slightly by typeface:
* Poster (extremely large sizes, usually larger than 72 point)
* Display (large sizes, typically 19-72 point)
* Subhead (large text, typically about 14-18 point)
* (regular is usually left unnamed, typically about 10-13 point)
* Small text (SmText, typically about 8-10 point)
* Caption (very small, typically about 6-8 point)
[edit] Metrics
Font metrics refers to metadata consisting of numeric values relating to
size and space in the font overall, or in its individual glyphs.
Font-wide metrics include cap height, x-height, ascender height,
descender depth, and the font bounding box. Glyph-level metrics include
the glyph bounding box, the advance width (total space for the glyph),
and sidebearings (space that pads the glyph outline on either side).
[edit] Serifs
Italic capital swashes
Serifness of the Thesis typeface
Although most typefaces are characterised by their use of serifs, there
are superfamilies that incorporate serif (antiqua) and sans-serif
(grotesque) or even intermediate slab serif (egyptian) or semi-serif
fonts with the same base outlines.
A more common font variant, especially of serif typefaces, is that of
alternate capitals. They can have swashes to go with italic minuscules
or they can be of a flourish design for use as initials (drop caps).
[edit] Proportion
Just like serifness, most typefaces either have proportional or
monospaced (typewriter-style) letter widths, if the script provides the
possibility. There are, however, superfamilies covering both styles.
Some fonts provide both proportional and fixed-width (tabular) digits,
where the former usually coincide with lowercase text figures and the
latter with uppercase lining figures.
[edit] Etymology
The term font, a cognate of the word fondue, derives from Middle French
fonte, meaning "(something that has been) melt(ed)", referring to type
produced by casting molten metal at a type foundry. English-speaking
printers have used the term fount for centuries to refer to the
multi-part metal type used to assemble and print in a particular size
and typeface.[2]A computer font
(or fount) is an electronic data file containing a set of glyphs,
characters, or symbols such as dingbats. Although the term font first
referred to a set of metal type sorts in one style and size, since the
1990s most fonts are digital, used on computers.
There are three basic kinds of computer font file data formats:
* Bitmap fonts consist of a series of dots or pixels representing the
image of each glyph in each face and size.
* Outline fonts (also called vector fonts) use Bézier curves, drawing
instructions and mathematical formulas to describe each glyph, which
make the character outlines scalable to any size.
* Stroke fonts use a series of specified lines and additional
information to define the profile, or size and shape of the line in a
specific face, which together describe the appearance of the glyph.
Bitmap fonts are faster and easier to use in computer code, but
inflexible, requiring a separate font for each size. Outline and stroke
fonts can be resized using a single font and substituting different
measurements for components of each glyph, but are somewhat more
complicated to use than bitmap fonts as they require additional computer
code to render the outline to a bitmap for display on screen or in
print.
A bitmap image can be displayed in a different size only with some
distortion, but renders quickly; outline or stroke image formats are
resizable but take more time to render as pixels must be drawn from
scratch each time they are displayed.
Fonts are designed and created using font editors. Fonts specifically
designed for the computer screen and not printing are known as
screenfonts.
Contents
[hide]
* 1 Font types
o 1.1 Bitmap fonts
+ 1.1.1 Monochrome fonts vs. fonts with shades of gray
+ 1.1.2 Scaling
+ 1.1.3 Bitmap font formats
o 1.2 Outline fonts
o 1.3 Stroke-based fonts
* 2 Font formats
o 2.1 Type 1 and Type 3 fonts
o 2.2 TrueType font
o 2.3 OpenType font
o 2.4 METAFONT
* 3 See also
* 4 Notes
* 5 External links
[edit] Font types
[edit] Bitmap fonts
An assortment of bitmap fonts from the first version of the Macintosh
operating system.
A bitmap font is one that stores each glyph as an array of pixels (that
is, a bitmap). It is less commonly known as a raster font. Bitmap fonts
are simply collections of raster images of glyphs. For each variant of
the font, there is a complete set of glyph images, with each set
containing an image for each character. For example, if a font has three
sizes, and any combination of bold and italic, then there must be 6
complete sets of images.
Advantages of bitmap fonts include:
* Extremely fast and simple to render
* Unscaled bitmap fonts always give exactly the same output
* Easier to create than other kinds.
The primary disadvantage of bitmap fonts is that the visual quality
tends to be poor when scaled or otherwise transformed, compared to
outline and stroke fonts, and providing many optimized and purpose-made
sizes of the same font dramatically increases memory usage. The earliest
bitmap fonts were only available in certain optimized sizes such as 8,
9, 10, 12, 14, 18, 24, 36, 48, 72, and 96 points, with custom fonts
often available in only one specific size, such as a headline font at
only 72 points.
The limited processing power and memory of early computer systems forced
exclusive use of bitmap fonts. Improvements in hardware have allowed
them to be replaced with outline or stroke fonts in cases where
arbitrary scaling is desirable, but bitmap fonts are still in common use
in embedded systems and other places where speed and simplicity are
considered important.
Bitmap fonts are used in the Linux console, the Windows recovery
console, and embedded systems. Older dot matrix printers used bitmap
fonts; often stored in the memory of the printer and addressed by the
computer's print driver. Dot matrix printers are still used on carbon
paper business forms. Bitmap fonts may be used in cross-stitch.
To draw a string using a bitmap font, means to successively output
bitmaps of each character that the string comprises, performing
per-character indentation. Also true type fonts, bitmap fonts can be
monospaced (i.e.. every character is plotted a constant distance from
the previous character that it is next to, while drawing) or
proportional (each character has its own width). However, the particular
font-handling application determines how each font will be displayed.
[edit] Monochrome fonts vs. fonts with shades of gray
Digital bitmap fonts (and the final rendering of vector fonts) may use
monochrome or shades of gray. The latter is anti-aliased. When
displaying a text, typically an operating system properly represents the
"shades of gray" as intermediate colors between the color of the font
and that of the background. However, if the text is represented as an
image with transparent background, "shades of gray" require an image
format allowing partial transparency.
[edit] Scaling
Bitmap fonts look best at their native pixel size. Some systems using
bitmap fonts can create some font variants algorithmically. For example,
the original Apple Macintosh computer could produce bold by widening
vertical strokes and oblique by shearing the image. At non-native sizes,
many text rendering systems perform nearest-neighbor resampling,
introducing ugly jagged edges. More advanced systems perform
anti-aliasing on bitmap fonts whose size does not match the size that
the application requests. This technique works well for making the font
smaller but not as well for increasing the size, as it tends to blur the
edges. Some graphics systems that use bitmap fonts, especially those of
emulators, apply curve-sensitive nonlinear resampling algorithms such as
2xSaI or hq3x on fonts and other bitmaps, which avoids blurring the font
while introducing little objectionable distortion at moderate increases
in size.
The difference between bitmap fonts and outline fonts is similar to the
difference between bitmap and vector image file formats. Bitmap fonts
are like image formats such as Windows Bitmap (.bmp), Portable Network
Graphics (.png) and Tagged Image Format (.tif or .tiff), which store the
image data as a grid of pixels, in some cases with compression. Outline
or stroke image formats such as Windows Metafile format (.wmf) and
Scalable Vector Graphics format (.svg), store instructions in the form
of lines and curves of how to draw the image rather than storing the
image itself.
A "trace" program can follow the outline of a high-resolution bitmap
font and create an initial outline that a font designer uses to create
an outline font useful in systems such as PostScript or TrueType.
Outline fonts scale easily without jagged edges or blurriness.
[edit] Bitmap font formats
A bitmap color font for the Amiga OS.
* Portable Compiled Font (PCF)
* Glyph Bitmap Distribution Format (BDF)
* Server Normal Format (SNF)
* DECWindows Font (DWF)
* Sun X11/NeWS format (BF, AFM)
* Microsoft Windows bitmapped font (FON)
* Amiga Font, ColorFont, AnimFont
* ByteMap Font (BMF)
* PC Screen Font (PSF)
[edit] Outline fonts
Outline fonts or vector fonts are collections of vector images, i.e. a
set of lines and curves to define the border of glyphs. Early vector
fonts were used by vector monitors and vector plotters using their own
internal fonts, usually with thin single strokes instead of thick
outlined glyphs. The advent of desktop publishing brought the need for a
universal standard to integrate the graphical user interface of the
first Macintosh and laser printers. The term to describe the integration
technology was WYSIWYG (What You See Is What You Get). The universal
standard was (and still is) Adobe PostScript. Examples are PostScript
Type 1 and Type 3 fonts, TrueType and OpenType.
The primary advantage of outline fonts is that they can be easily
transformed by applying a mathematical function to each vector point,
scaling them without causing pixellation. Outline font characters can be
scaled to any size and otherwise transformed with more attractive
results than bitmap fonts, but requires considerably more processing and
may yield undesirable rendering, depending on the font, rendering
software, and output size.
Outline fonts have a major problem, in that Bézier curves cannot be
rendered accurately onto a raster display (such as most computer
monitors and printers), and their rendering can change shape depending
on the desired size and position.[1] Measures such as font hinting have
to be used to reduce the visual impact of this problem, which require
sophisticated software that is difficult to implement correctly. Many
modern desktop computer systems include software to do this, but they
use considerably more processing power than bitmap fonts, and there can
be minor rendering defects, particularly at small font sizes. Despite
this, they are frequently used because people often consider the
processing time and defects to be acceptable when compared to the
ability to scale fonts freely.
[edit] Stroke-based fonts
A glyph's outline is defined by the vertices of individual strokes and
stroke's profile. Its advantages over outline fonts include reducing
number of vertices needed to define a glyph, allowing the same vertices
to be used to generate a font with a different weight, glyph width, or
serifs using different stroke rules, and the associated size savings.
For a font developer, editing a glyph by stroke is easier and less prone
to error than editing outlines. A stroke-based system also allows
scaling glyphs in height or width without altering stroke thickness of
the base glyphs. Stroke-based fonts are heavily marketed for East Asian
markets for use on embedded devices, but the technology is not limited
to ideograms.
Commercial developers included Agfa Monotype (iType), Type Solutions,
Inc. (owned by Bitstream Inc.) (Font Fusion (FFS), btX2), Fontworks (Gaiji
Master), which have independently developed stroke-based font types and
font engines.
Although Monotype and Bitstream have claimed tremendous space saving
using stroke-based fonts on East Asian character sets, most of the space
saving comes from building composite glyphs, which is part of the
TrueType specification and does not require stroke-based approach.
[edit] Font formats
[edit] Type 1 and Type 3 fonts
Type 1 and Type 3 fonts were developed by Adobe for professional digital
typesetting. Using PostScript, the glyphs are outline fonts described
with cubic Bezier curves. Type 1 fonts were restricted to a subset of
the PostScript language, and used Adobe's hinting system, which used to
be very expensive. Type 3 allowed unrestricted use of the PostScript
language, but didn't include any hint information, which could lead to
visible rendering artifacts on low-resolution devices (such as computer
screens and dot-matrix printers).
[edit] TrueType font
TrueType is a font system originally developed by Apple, Inc. It was
intended to replace Type 1 fonts, which many felt were too expensive.
Unlike Type 1 fonts, TrueType glyphs are described with quadratic Bezier
curves. It is currently very popular and implementations exist for all
major operating systems.
[edit] OpenType font
OpenType is a smartfont system designed by Adobe and Microsoft. OpenType
fonts contain outlines in either the TrueType or Type 1 (actually CFF)
format together with a wide range of metadata.
[edit] METAFONT
METAFONT uses a different sort of glyph description. Like TrueType, it
is a vector font description system. It draws glyphs using strokes
produced by moving a polygonal or elliptical pen approximated by a
polygon along a path made from cubic Bézier splines and straight line
segments, or by filling such paths. Although when stroking a path the
envelope of the stroke is never actually generated, the method causes no
loss of accuracy or resolution.
The Above Font Information is from
Wikipedia.
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