HOME

TheInfoList



OR:

TrueType is an outline font standard developed by
Apple An apple is an edible fruit produced by an apple tree (''Malus domestica''). Apple trees are cultivated worldwide and are the most widely grown species in the genus '' Malus''. The tree originated in Central Asia, where its wild ancest ...
in the late 1980s as a competitor to
Adobe Adobe ( ; ) is a building material made from earth and organic materials. is Spanish for '' mudbrick''. In some English-speaking regions of Spanish heritage, such as the Southwestern United States, the term is used to refer to any kind of ...
's Type 1 fonts used in
PostScript PostScript (PS) is a page description language in the electronic publishing and desktop publishing realm. It is a dynamically typed, concatenative programming language. It was created at Adobe Systems by John Warnock, Charles Geschke, Do ...
. It has become the most common format for fonts on the
classic Mac OS Mac OS (originally System Software; retronym: Classic Mac OS) is the series of operating systems developed for the Macintosh family of personal computers by Apple Computer from 1984 to 2001, starting with System 1 and ending with Mac OS 9. ...
,
macOS macOS (; previously OS X and originally Mac OS X) is a Unix operating system developed and marketed by Apple Inc. since 2001. It is the primary operating system for Apple's Mac computers. Within the market of desktop and la ...
, and
Microsoft Windows Windows is a group of several proprietary graphical operating system families developed and marketed by Microsoft. Each family caters to a certain sector of the computing industry. For example, Windows NT for consumers, Windows Server for ...
operating systems. The primary strength of TrueType was originally that it offered
font In metal typesetting, a font is a particular size, weight and style of a typeface. Each font is a matched set of type, with a piece (a " sort") for each glyph. A typeface consists of a range of such fonts that shared an overall design. In mo ...
developers a high degree of control over precisely how their fonts are displayed, right down to particular
pixel In digital imaging, a pixel (abbreviated px), pel, or picture element is the smallest addressable element in a raster image, or the smallest point in an all points addressable display device. In most digital display devices, pixels are the ...
s, at various font sizes. With widely varying rendering technologies in use today, pixel-level control is no longer certain in a TrueType font.


History

''TrueType'' was known during its development stage, first by the codename "Bass" and later on by the codename "Royal". The system was developed and eventually released as TrueType with the launch of Mac System 7 in May 1991. The initial TrueType outline fonts, four-weight families of '' Times Roman'', ''
Helvetica Helvetica (originally Neue Haas Grotesk) is a widely used sans-serif typeface developed in 1957 by Swiss typeface designer Max Miedinger and Eduard Hoffmann. Helvetica is a neo-grotesque design, one influenced by the famous 19th century (1890s) ...
'', ''
Courier A courier is a person or organisation that delivers a message, package or letter from one place or person to another place or person. Typically, a courier provides their courier service on a commercial contract basis; however, some couriers are ...
'', and the pi font "Symbol" replicated the original PostScript fonts of the Apple LaserWriter. Apple also replaced some of their bitmap fonts used by the graphical user-interface of previous Macintosh System versions (including Geneva, Monaco and New York) with scalable TrueType outline-fonts. For compatibility with older systems, Apple shipped these fonts, a TrueType
Extension Extension, extend or extended may refer to: Mathematics Logic or set theory * Axiom of extensionality * Extensible cardinal * Extension (model theory) * Extension (predicate logic), the set of tuples of values that satisfy the predicate * Ext ...
and a TrueType-aware version of Font/DA Mover for
System 6 System 6 (or System Software 6) is a graphical user interface-based operating system for Macintosh computers, made by Apple Computer It was released in 1988, and is part of the classic Mac OS series. It is a monolithic operating system, with ...
. For compatibility with the Laserwriter II, Apple developed fonts like ITC Bookman and ITC Chancery in TrueType format. All of these fonts could now scale to all sizes on screen and printer, making the Macintosh System 7 the first OS to work without any bitmap fonts. The early TrueType systems — being still part of Apple's QuickDraw graphics subsystem — did not render Type 1 fonts on-screen as they do today. At the time, many users had already invested considerable money in Adobe's still proprietary Type 1 fonts. As part of Apple's tactic of opening the font format versus Adobe's desire to keep it closed to all but Adobe licensees, Apple licensed TrueType to
Microsoft Microsoft Corporation is an American multinational technology corporation producing computer software, consumer electronics, personal computers, and related services headquartered at the Microsoft Redmond campus located in Redmond, Washi ...
. When TrueType and the license to Microsoft was announced,
John Warnock John Edward Warnock (born October 6, 1940) is an American computer scientist and businessman best known for co-founding Adobe Systems Inc., the graphics and publishing software company, with Charles Geschke. Warnock was President of Adobe for ...
co-founder and then CEO of Adobe, gave an impassioned speech in which he claimed Apple and Microsoft were selling
snake oil Snake oil is a term used to describe deceptive marketing, health care fraud, or a scam. Similarly, "snake oil salesman" is a common expression used to describe someone who sells, promotes, or is a general proponent of some valueless or fraudu ...
, and then announced that the Type 1 format was open for anyone to use. Meanwhile, in exchange for TrueType, Apple got a license for TrueImage, a
PostScript PostScript (PS) is a page description language in the electronic publishing and desktop publishing realm. It is a dynamically typed, concatenative programming language. It was created at Adobe Systems by John Warnock, Charles Geschke, Do ...
-compatible page-description language owned by Microsoft that Apple could use in laser printing. This was never actually included in any Apple products when a later deal was struck between Apple and Adobe, where Adobe promised to put a TrueType interpreter in their PostScript printer boards. Apple renewed its agreements with Adobe for the use of PostScript in its printers, resulting in lower royalty payments to Adobe, who was beginning to license printer controllers capable of competing directly with Apple's LaserWriter printers. Part of
Adobe Adobe ( ; ) is a building material made from earth and organic materials. is Spanish for '' mudbrick''. In some English-speaking regions of Spanish heritage, such as the Southwestern United States, the term is used to refer to any kind of ...
's response to learning that TrueType was being developed was to create the Adobe Type Manager software to scale Type 1 fonts for anti-aliased output on-screen. Although ATM initially cost money, rather than coming free with the operating system, it became a ''de facto'' standard for anyone involved in
desktop publishing Desktop publishing (DTP) is the creation of documents using page layout software on a personal ("desktop") computer. It was first used almost exclusively for print publications, but now it also assists in the creation of various forms of online ...
. Anti-aliased rendering, combined with Adobe applications' ability to zoom in to read small type, and further combined with the now open PostScript Type 1 font format, provided the impetus for an explosion in font design and in desktop publishing of newspapers and magazines. Apple extended TrueType with the launch of
TrueType GX QuickDraw GX was a replacement for the QuickDraw (QD) 2D graphics engine and Printing Manager inside the classic Mac OS. Its underlying drawing platform was a resolution-independent object oriented retained mode system, making it much easier for ...
in 1994, with additional tables in the sfnt which formed part of QuickDraw GX. This offered powerful extensions in two main areas. First was font axes (today known as variations), for example allowing fonts to be smoothly adjusted from light to bold or from narrow to extended — competition for Adobe's " multiple master" technology. Second was Line Layout Manager, where particular sequences of characters can be coded to flip to different designs in certain circumstances, useful for example to offer ligatures for "fi", "ffi", "ct", etc. while maintaining the backing store of characters necessary for
spell checker In software, a spell checker (or spelling checker or spell check) is a software feature that checks for misspellings in a text. Spell-checking features are often embedded in software or services, such as a word processor, email client, electronic ...
s and text searching. However, the lack of user-friendly tools for making TrueType GX fonts meant there were no more than a handful of GX fonts. Much of the technology in TrueType GX, including variations and substitution, lives on as AAT (
Apple Advanced Typography Apple Advanced Typography (AAT) is Apple Inc.'s computer technology for advanced font rendering, supporting internationalization and complex features for typographers, a successor to Apple's little-used QuickDraw GX font technology of the mid- ...
) in
macOS macOS (; previously OS X and originally Mac OS X) is a Unix operating system developed and marketed by Apple Inc. since 2001. It is the primary operating system for Apple's Mac computers. Within the market of desktop and la ...
. Few font-developers outside Apple attempt to make AAT fonts; instead,
OpenType OpenType is a format for scalable computer fonts. It was built on its predecessor TrueType, retaining TrueType's basic structure and adding many intricate data structures for prescribing typographic behavior. OpenType is a registered trademark ...
has become the dominant sfnt format, and all of the font variation technology is the de facto standard today in OpenType Variations.


Adoption by Microsoft

To ensure its wide adoption, Apple licensed TrueType to Microsoft for free. Microsoft added TrueType into the
Windows 3.1 Windows 3.1 is a major release of Microsoft Windows. It was released to manufacturing on April 6, 1992, as a successor to Windows 3.0. Like its predecessors, the Windows 3.1 series ran as a shell on top of MS-DOS. Codenamed Janus, Windows ...
operating environment. In partnership with their contractors, Monotype Imaging, Microsoft put a lot of effort into creating a set of high quality TrueType fonts that were compatible with the core fonts being bundled with PostScript equipment at the time. This included the fonts that are standard with Windows to this day: Times New Roman (compatible with Times Roman),
Arial Arial (also called Arial MT) is a sans-serif typeface and set of computer fonts in the neo-grotesque style. Fonts from the Arial family are included with all versions of Microsoft Windows from Windows 3.1 on, some other Microsoft software ...
(compatible with Helvetica) and
Courier New Courier is a monospaced slab serif typeface. The typeface was designed by Howard "Bud" Kettler (1919–1999). Initially created for IBM's typewriters, it has been adapted for use as a computer font, and versions of it are installed on most deskt ...
(compatible with Courier). In this context, "compatible" means two things. On an aesthetic level, it means that the fonts are similar in appearance. On a functional level, it means that the fonts have the same character widths. This allows documents which have been typeset in one font to be changed to the other, without reflow. Microsoft and Monotype technicians used TrueType's
hinting Font hinting (also known as instructing) is the use of mathematical instructions to adjust the display of an outline font so that it lines up with a rasterized grid. At low screen resolutions, hinting is critical for producing clear, legible tex ...
technology to ensure that these fonts did not suffer from the problem of illegibility at low resolutions, which had previously forced the use of bitmapped fonts for screen display. Subsequent advances in technology have introduced first anti-aliasing, which smooths the edges of fonts at the expense of a slight blurring, and more recently subpixel rendering (the Microsoft implementation goes by the name ClearType), which exploits the pixel structure of LCD based displays to increase the apparent resolution of text. Microsoft has heavily marketed ClearType, and sub-pixel rendering techniques for text are now widely used on all platforms. Microsoft also developed a " smart font" technology, named ''TrueType Open'' in 1994, later renamed to
OpenType OpenType is a format for scalable computer fonts. It was built on its predecessor TrueType, retaining TrueType's basic structure and adding many intricate data structures for prescribing typographic behavior. OpenType is a registered trademark ...
in 1996 when it merged support of the
Adobe Adobe ( ; ) is a building material made from earth and organic materials. is Spanish for '' mudbrick''. In some English-speaking regions of Spanish heritage, such as the Southwestern United States, the term is used to refer to any kind of ...
Type 1 glyph outlines. Opentype now contains all of the same functionality of Apple TrueType and Apple TrueType GX.


TrueType today


Macintosh and Microsoft Windows

TrueType has long been the most common format for fonts on
classic Mac OS Mac OS (originally System Software; retronym: Classic Mac OS) is the series of operating systems developed for the Macintosh family of personal computers by Apple Computer from 1984 to 2001, starting with System 1 and ending with Mac OS 9. ...
,
Mac OS X macOS (; previously OS X and originally Mac OS X) is a Unix operating system developed and marketed by Apple Inc. since 2001. It is the primary operating system for Apple's Mac computers. Within the market of desktop and lap ...
, and
Microsoft Windows Windows is a group of several proprietary graphical operating system families developed and marketed by Microsoft. Each family caters to a certain sector of the computing industry. For example, Windows NT for consumers, Windows Server for ...
, although Mac OS X and Microsoft Windows also include native support for Adobe's Type 1 format and the
OpenType OpenType is a format for scalable computer fonts. It was built on its predecessor TrueType, retaining TrueType's basic structure and adding many intricate data structures for prescribing typographic behavior. OpenType is a registered trademark ...
extension to TrueType (since Mac OS X 10.0 and
Windows 2000 Windows 2000 is a major release of the Windows NT operating system developed by Microsoft and oriented towards businesses. It was the direct successor to Windows NT 4.0, and was released to manufacturing on December 15, 1999, and was offici ...
). While some fonts provided with the new operating systems are now in the OpenType format, most free or inexpensive third-party fonts use plain TrueType. Increasing resolutions and new approaches to screen rendering have reduced the requirement of extensive TrueType hinting. Apple's rendering approach on macOS ignores almost all the hints in a TrueType font, while Microsoft's ClearType ignores many hints, and according to Microsoft, works best with "lightly hinted" fonts.


Linux and other platforms

The FreeType project of David Turner has created an independent implementation of the TrueType standard (as well as other font standards in FreeType 2). FreeType is included in many
Linux Linux ( or ) is a family of open-source Unix-like operating systems based on the Linux kernel, an operating system kernel first released on September 17, 1991, by Linus Torvalds. Linux is typically packaged as a Linux distribution, whi ...
distributions. Until May 2010, there were potential patent infringements in FreeType 1 because parts of the TrueType
hinting Font hinting (also known as instructing) is the use of mathematical instructions to adjust the display of an outline font so that it lines up with a rasterized grid. At low screen resolutions, hinting is critical for producing clear, legible tex ...
virtual machine were
patent A patent is a type of intellectual property that gives its owner the legal right to exclude others from making, using, or selling an invention for a limited period of time in exchange for publishing an enabling disclosure of the invention."A ...
ed by Apple, a fact not mentioned in the TrueType standards. (Patent holders who contribute to standards published by a major standards body such as ISO are required to disclose the scope of their patents, but TrueType was not such a standard.) FreeType 2 included an optional automatic hinter to avoid the patented technology, but these patents have now expired so FreeType 2.4 now enables these features by default.


Technical notes


Outlines

The outlines of the characters (or
glyph A glyph () is any kind of purposeful mark. In typography, a glyph is "the specific shape, design, or representation of a character". It is a particular graphical representation, in a particular typeface, of an element of written language. A g ...
s) in TrueType fonts are made of straight line segments and quadratic
Bézier curve A Bézier curve ( ) is a parametric curve used in computer graphics and related fields. A set of discrete "control points" defines a smooth, continuous curve by means of a formula. Usually the curve is intended to approximate a real-world shape ...
s. These curves are mathematically simpler and faster to process than cubic Bézier curves, which are used both in the
PostScript PostScript (PS) is a page description language in the electronic publishing and desktop publishing realm. It is a dynamically typed, concatenative programming language. It was created at Adobe Systems by John Warnock, Charles Geschke, Do ...
-centered world of
graphic design Graphic design is a profession, academic discipline and applied art whose activity consists in projecting visual communications intended to transmit specific messages to social groups, with specific objectives. Graphic design is an interdiscip ...
and in Type 1 fonts. However, most shapes require more points to describe with quadratic curves than cubics. This difference also means that it is not possible to convert Type 1 losslessly to the TrueType format, although in practice it is often possible to do a lossless conversion from TrueType to Type 1.


Hinting language

TrueType systems include a
virtual machine In computing, a virtual machine (VM) is the virtualization/ emulation of a computer system. Virtual machines are based on computer architectures and provide functionality of a physical computer. Their implementations may involve specialized h ...
that executes programs inside the font, processing the " hints" of the
glyph A glyph () is any kind of purposeful mark. In typography, a glyph is "the specific shape, design, or representation of a character". It is a particular graphical representation, in a particular typeface, of an element of written language. A g ...
s, in TrueType called “instructions”. These distort the control points which define the outline, with the intention that the rasterizer produce fewer undesirable features on the glyph. Each glyph's instruction set takes account of the size (in pixels) at which the glyph is to be displayed, as well as other less important factors of the display environment. Although incapable of receiving input and producing output as normally understood in programming, the TrueType instruction language does offer the other prerequisites of programming languages:
conditional branch A branch is an instruction in a computer program that can cause a computer to begin executing a different instruction sequence and thus deviate from its default behavior of executing instructions in order. ''Branch'' (or ''branching'', ''bran ...
ing (IF statements),
looping Looping may refer to: Media and entertainment * Loop (music), a repeating section of sound material * Audio induction loop, an aid for the hard of hearing * a film production term for dubbing (filmmaking) * repeating drawings in an animated cartoo ...
an arbitrary number of times (FOR- and WHILE-type statements), variables (although these are simply numbered slots in an area of memory reserved by the font), and encapsulation of code into functions. Special instructions called delta instructions are the lowest level control, moving a control point at just one pixel size. The hallmark of effective TrueType glyph programming techniques is that it does as much as possible using variables defined just once in the whole font (e.g., stem widths,
cap height In typography, cap height is the height of a capital letter above the baseline for a particular typeface A typeface (or font family) is the design of lettering that can include variations in size, weight (e.g. bold), slope (e.g. italic), wi ...
,
x-height upright 2.0, alt=A diagram showing the line terms used in typography In typography, the x-height, or corpus size, is the distance between the baseline and the mean line of lowercase letters in a typeface. Typically, this is the height of the le ...
). This means avoiding delta instructions as much as possible. This helps the font developer to make major changes (e.g., the point at which the entire font's main stems jump from 1 to 2 pixels wide) most of the way through development. Creating a very well-instructed TrueType font remains a significant amount of work, despite the increased user-friendliness of programs for adding instructions to fonts. Many TrueType fonts therefore have only rudimentary instructions, or have them automatically applied by the font editor, with results of various quality.


Embedding protection

The TrueType format allows for the most basic type of
digital rights management Digital rights management (DRM) is the management of legal access to digital content. Various tools or technological protection measures (TPM) such as access control technologies can restrict the use of proprietary hardware and copyrighted work ...
 – an ''embeddable flag field'' that specifies whether the author allows embedding of the font file into things like
PDF Portable Document Format (PDF), standardized as ISO 32000, is a file format developed by Adobe in 1992 to present documents, including text formatting and images, in a manner independent of application software, hardware, and operating systems. ...
files and websites. Anyone with access to the font file can directly modify this field, and simple tools exist to facilitate modifying it (obviously, modifying this field does not modify the font license and does not give extra legal rights). These tools have been the subject of controversy over potential copyright issues.


Font formats


TrueType Collection

TrueType Collection (TTC) is an extension of TrueType format that allows combining multiple fonts into a single file, creating substantial space savings for a collection of fonts with many glyphs in common. They were first available in Chinese, Japanese, and Korean versions of Windows, and supported for all regions in Windows 2000 and later. Classic Mac OS included support of TTC starting with Mac OS 8.5. In classic Mac OS and macOS, TTC has file type .


Emoji

Apple has implemented a proprietary extension to allow color .ttf files for its
emoji An emoji ( ; plural emoji or emojis) is a pictogram, logogram, ideogram or smiley embedded in text and used in electronic messages and web pages. The primary function of emoji is to fill in emotional cues otherwise missing from typed conv ...
font
Apple Color Emoji Apple Color Emoji (stylized as AppleColorEmoji) is a color typeface used on Apple platforms such as iOS and macOS to display Emoji characters. The inclusion of emoji in the iPhone and in the Unicode standard has been credited with promoting the ...
.


File formats


Basic

A basic font is composed of multiple tables specified in its header. A table name can have up to 4 letters. A TrueType Collection file begins with a ttcf table that allows access to the fonts within the collection by pointing to individual headers for each included font. The fonts within a collection share the same glyph-outline table, though each font can refer to subsets within those outlines in its own manner, through its 'cmap', 'name' and 'loca' tables. A .ttf extension indicates a regular TrueType font or an OpenType font with TrueType outlines, while a .ttc extension is reserved for TTCs. Windows end user defined character editor (EUDCEDIT.EXE) creates TrueType font with name EUDC.TTE. An OpenType font with PostScript outlines must have an .otf extension. In principle an OpenType font with TrueType outlines may have an .otf extension, but this has rarely been done in practice. In classic Mac OS and macOS, OpenType is one of several formats referred to as data-fork fonts, as they lack the classic Mac resource fork.


Suitcase

The suitcase format for TrueType is used on classic Mac OS and macOS. It adds additional Apple-specific information. Like TTC, it can handle multiple fonts within a single file. But unlike TTC, those fonts need not be within the same family. Suitcases come in resource-fork and data-fork formats. The resource-fork version was the original suitcase format. Data-fork-only suitcases, which place the resource fork contents into the data fork, were first supported in macOS. A suitcase packed into the data-fork-only format has the extension '' dfont''.


PostScript

In the
PostScript PostScript (PS) is a page description language in the electronic publishing and desktop publishing realm. It is a dynamically typed, concatenative programming language. It was created at Adobe Systems by John Warnock, Charles Geschke, Do ...
language, TrueType outlines are handled with a PostScript wrapper as Type 42 for name-keyed or Type 11 for CID-keyed fonts.


See also

* ClearType * Datafork TrueType * Embedded TrueType font * Open-source Unicode typefaces * GNU FreeFont * Graphite (SIL) * FreeType * Nonzero-rule *
Online office suite An online office suite, online productivity suite or cloud office suite is an office suite offered in the form of a web application. It is accessed online using a web browser. This allows people to work together worldwide and at any time, thereby le ...
*
OpenType OpenType is a format for scalable computer fonts. It was built on its predecessor TrueType, retaining TrueType's basic structure and adding many intricate data structures for prescribing typographic behavior. OpenType is a registered trademark ...
* Pango (Open source multilingual text rendering engine) *
Typography Typography is the art and technique of arranging type to make written language legible, readable and appealing when displayed. The arrangement of type involves selecting typefaces, point sizes, line lengths, line-spacing ( leading), an ...
*
Typeface A typeface (or font family) is the design of lettering that can include variations in size, weight (e.g. bold), slope (e.g. italic), width (e.g. condensed), and so on. Each of these variations of the typeface is a font. There are thousands o ...
*
Unicode Unicode, formally The Unicode Standard,The formal version reference is is an information technology standard for the consistent encoding, representation, and handling of text expressed in most of the world's writing systems. The standard, ...
,
UTF-8 UTF-8 is a variable-length character encoding used for electronic communication. Defined by the Unicode Standard, the name is derived from ''Unicode'' (or ''Universal Coded Character Set'') ''Transformation Format 8-bit''. UTF-8 is capable of e ...
, Unicode fonts. * Uniscribe (Windows multilingual text rendering engine) *
Apple Type Services for Unicode Imaging The Apple Type Services for Unicode Imaging (ATSUI) is the set of services for rendering Unicode-encoded text introduced in Mac OS 8.5 and carried forward into Mac OS X. It replaced the WorldScript engine for legacy encodings. Obsolescence ...
(New Macintosh multilingual text rendering engine) *
Core Text Core Text is a Core Foundation style API in macOS, first introduced in Mac OS X 10.4 Tiger, made public in Mac OS X 10.5 Leopard, and introduced for the iPad with iPhone SDK 3.2. Exposing a C API, it replaces the text rendering abilities of th ...
*
WorldScript WorldScript is the multilingual text rendering engine for Apple Macintosh's classic Mac OS, before Mac OS X was introduced. Starting with version 7.1, Apple unified the implementation of non-Roman script systems in a programming interface called W ...
(Old Macintosh multilingual text rendering engine) *
Web Open Font Format The Web Open Font Format (WOFF) is a font format for use in web pages. WOFF files are OpenType or TrueType fonts, with format-specific compression applied and additional XML metadata added. The two primary goals are first to distinguish font file ...


References


External links


TrueType specification (Apple)
{{Typography terms Typesetting Digital typography Font formats