TrueType is an outline font standard Standardization or standardisation is the process of developing and agreeing upon technical standards. A standard is a document that establishes uniform engineering or technical specifications, criteria, methods, processes, or practices. Some standards are mandatory while others are voluntary. Voluntary standards are available if one chooses to originally developed by Apple Computer Apple Inc. is an American multinational corporation that designs and markets consumer electronics, computer software, and personal computers. The company's best-known hardware products include the Macintosh computers, the iPod, the iPhone and the iPad. Apple software includes the Mac OS X operating system; the iTunes media browser; the iLife suite in the late 1980s as a competitor to Adobe Adobe Systems Incorporated (NASDAQ: ADBE) is an American computer software company headquartered in San Jose, California, USA. The company has historically focused upon the creation of multimedia and creativity software products, with a more-recent foray towards rich Internet application software development's Type 1 fonts used in PostScript PostScript is a dynamically typed concatenative programming language created by John Warnock and Charles Geschke in 1982. PostScript is best known for its use as a page description language in the electronic and desktop publishing areas.
The primary strength of TrueType was originally that it offered font In typography, a font is traditionally defined as a quantity of sorts composing 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 developers a high degree of control over precisely how their fonts are displayed, right down to particular pixels In digital imaging, a pixel is a single point in a raster image. The pixel is the smallest addressable screen element; it is the smallest unit of picture that can be controlled. Each pixel has its own address. The address of a pixel corresponds to its coordinates. Pixels are normally arranged in a 2-dimensional grid, and are often represented, at various font sizes (with widely varying rendering Rendering is the process of generating an image from a model, by means of computer programs. The model is a description of three-dimensional objects in a strictly defined language or data structure. It would contain geometry, viewpoint, texture, lighting, and shading information. The image is a digital image or raster graphics image. The term may technologies in use today, pixel-level control is no longer certain).
Contents |
History
Apple
On the Macintosh, fonts were originally stored in hand-tuned bitmap font A computer font 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 files that specified individual pixel locations for a font at a particular size. If the user wanted to see a font at another size, the Font Manager would find the closest match and apply a basic scaling algorithm. When scaled to large sizes the algorithm was of limited use, with the output becoming blocky.
In contrast, printer fonts for the popular Apple LaserWriter were based on PostScript Type 1 outlines, resulting in excellent output at any size. Outline fonts have a set of drawing instructions for lines and curves to create a shape for each character (a "glyph"). By following the drawing instructions, the computer creates an "outline" shape at a specific size, and then "fills" it with ink (e.g., black) to create the character. Glyphs scale to any size, and are independent of the resolution of the screen or printer. It produces the same quality whether it's printing to film, drawing on a screen, or printing a billboard. This technology was the key invention that the founders of Adobe Adobe is a natural building material made from sand, clay, water, and some kind of fibrous or organic material , which is shaped into bricks using frames and dried in the sun. It is similar to cob and mudbrick. Adobe structures are extremely durable and account for some of the oldest existing buildings in the world. In hot climates, compared to engineered and marketed as PostScript. Making matters difficult was the fact that Type 1 fonts were encrypted, and Adobe made a considerable amount of their income from licensing the format to interested parties. They were not about to simply allow Apple to include the software for free.
Instead Sampo Kaasila at Apple decided to write an entirely new format, which he worked on under the name Bass (because it was a scalable font format, and you can scale a fish, and perhaps as in Bass-o-matic 76 from the Saturday Night Live Saturday Night Live is a live late-night television sketch comedy and variety show developed by Lorne Michaels and Dick Ebersol. It premiered on NBC, a terrestrial television network in the United States, on October 11, 1975, under the title NBC's Saturday Night. The show's sketches often parody contemporary American popular culture and politics sketch) [1] and later Royal. The system developed and was eventually released as TrueType with the launch of Mac OS System 7 System 7 is a single-user graphical user interface-based operating system for Macintosh computers. It was introduced on May 13, 1991 by Apple Computer. It succeeded System 6, and was the main Macintosh operating system until it was succeeded by Mac OS 8 in 1997. Features added with the System 7 release included virtual memory, personal file in May 1991. The fonts, four-weight families of Times Roman Times New Roman is a serif typeface commissioned by the British newspaper, The Times, in 1931, designed by Stanley Morison and Victor Lardent at the English branch of Monotype. It was commissioned after Stanley Morison had written an article criticizing The Times for being badly printed and typographically behind the times. The font was supervised, Helvetica Helvetica is a widely used sans-serif typeface developed in 1957 by Swiss typeface designer Max Miedinger with Eduard Hoffmann, Courier Courier is a monospaced slab serif typeface designed to resemble the output from a strike-on typewriter. The typeface was designed by Howard "Bud" Kettler in 1955. The design of the original Courier typeface was commissioned in the 1950s by IBM for use in typewriters, but they did not secure legal exclusivity to the typeface and it soon, and a handful of others, replaced the older bitmap fonts A computer font 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 that previous Macintosh System versions had used. For compatibility with older systems, Apple also shipped a TrueType Extension On the Apple Macintosh operating system prior to Mac OS X, extensions were small pieces of code that extended the system's functionality. They were run initially at start-up time, and operated by a variety of mechanisms, including trap patching and other code modifying techniques. Initially an Apple developer hack, extensions became the standard and a TrueType aware version of Font/DA Mover for System Software 6 System 6 is a graphical user interface-based operating system for Macintosh computers. It was released in 1988 by Apple Computer and was part of the Mac OS line of operating systems. System 6 was shipped with various Macintosh computers until it was succeeded by System 7 in 1991. The boxed version of System 6 cost 49 USD when introduced.. System 6.
One huge drawback of the TrueType system is that it could not use Type 1 fonts on-screen. This meant that the system was in fact not used by the very people it was intended to help, desktop publishing software users. They had already invested considerable money in commercial Type 1 fonts, which they were not interested in replacing, and therefore had to continue using Adobe Type Manager (see below). Adding to the problem was that there were very few fonts available in TrueType format, so even if one wanted to start fresh there was no real way to do so.
As part of Apple's new tactic of distancing itself from Adobe, Apple licensed TrueType to Microsoft Microsoft Corporation is a public multinational corporation based in Redmond, Washington, USA that develops, manufactures, licenses, and supports a wide range of products and services predominantly related to computing through its various product divisions. Established on April 4, 1975 to develop and sell BASIC interpreters for the Altair 8800,, in exchange for a license for TrueImage, a PostScript PostScript is a dynamically typed concatenative programming language created by John Warnock and Charles Geschke in 1982. PostScript is best known for its use as a page description language in the electronic and desktop publishing areas-compatible printer control language owned by Microsoft that Apple planned to use in their laser printers A laser printer is a common type of computer printer that rapidly produces high quality text and graphics on plain paper. As with digital photocopiers and multifunction printers , laser printers employ a xerographic printing process but differ from analog photocopiers in that the image is produced by the direct scanning of a laser beam across the. This printer language was never actually included in any Apple products.
Part of Adobe Adobe Systems Incorporated (NASDAQ: ADBE) is an American computer software company headquartered in San Jose, California, USA. The company has historically focused upon the creation of multimedia and creativity software products, with a more-recent foray towards rich Internet application software development's response to learning that TrueType was being developed was to pre-emptively create the Adobe Type Manager software to scale Type 1 fonts on-screen and for output to any printer, much like TrueType fonts. 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 combines a personal computer and WYSIWYG page layout software to create publication documents on a computer for either large scale publishing or small scale local multifunction peripheral output and distribution.
When TrueType was announced, John Warnock John Edward Warnock is an American computer scientist best known as the co-founder with Charles Geschke of Adobe Systems Inc., the graphics and publishing software company. Dr. Warnock was President of Adobe for his first two years and Chairman and CEO for his remaining sixteen years at the company. Although retired as CEO in 2001, he still co- of Adobe gave an impassioned speech in which he claimed Apple and Microsoft were selling snake oil Snake oil is a traditional Chinese medicine made from the Chinese Water Snake , which is used to treat joint pain. However, the most common usage of the phrase is as a derogatory term for quack medicine. The expression is also applied metaphorically to any product with exaggerated marketing but questionable or unverifiable quality or benefit, and then instantly released the Type 1 format as a published standard for anyone to use. This put even more pressure on TrueType. Apple eventually renewed agreements with Adobe for the use of PostScript in its printers; it is speculated that Apple's tactics resulted in lower royalty payments to Adobe as part of its new licensing agreements.
Apple extended TrueType with the launch of TrueType GX in 1994, a smartfont technology that was part of QuickDraw GX. This offered powerful extensions in two main areas. First was font axes (morphing Morphing is a special effect in motion pictures and animations that changes one image into another through a seamless transition. Most often it is used to depict one person turning into another through technological means or as part of a fantasy or surreal sequence. Traditionally such a depiction would be achieved through cross-fading techniques), 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 substitution, where particular sequences of characters can be coded to flip to different designs in certain circumstances, useful for example to offer ligatures In writing and typography, a ligature occurs where two or more graphemes are joined as a single glyph. Ligatures usually replace consecutive characters sharing common components and are part of a more general class of glyphs called "contextual forms" where the specific shape of a letter depends on context such as surrounding letters or for "fi", "ffi", "ct", etc. while maintaining the backing store of characters necessary for spell-checkers In computing, a spell checker is an application program that flags words in a document that may not be spelled correctly. Spell checkers may be stand-alone capable of operating on a block of text, or as part of a larger application, such as a word processor, email client, electronic dictionary, or search engine 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 morphing and substitution, lives on as AAT (Apple Advanced Typography) in Mac OS X Mac OS X is a series of Unix-based operating systems and graphical user interfaces developed, marketed, and sold by Apple Inc. Since 2002, Mac OS X has been included with all new Macintosh computer systems. It is the successor to Mac OS 9, the final release of the "classic" Mac OS, which had been Apple's primary operating system since 198. 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 of Microsoft Corporation has become the dominant "smart font" technology, despite its lack of support for axes or multiple masters.
Microsoft
By 1991 Microsoft added TrueType into the Windows Microsoft Windows is a series of software operating systems and graphical user interfaces produced by Microsoft. Microsoft first introduced an operating environment named Windows in November 1985 as an add-on to MS-DOS in response to the growing interest in graphical user interfaces . Microsoft Windows came to dominate the world's personal 3.1 operating system. In partnership with their contractors, Monotype Corporation Monotype Imaging Holdings is a Delaware corporation based in Woburn, Massachusetts and specializing in typesetting and typeface design as well as text and imaging solutions for use with consumer electronics devices. Monotype Imaging Holdings is the owner of Monotype Imaging Inc., Linotype, International Typeface Corporation, among others. Monotype, Microsoft spent much effort 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, sometimes marketed as Arial MT, is a sans-serif typeface and computer font packaged with Microsoft Windows, other Microsoft software applications, Apple Mac OS X and many PostScript computer printers.[citation needed] The typeface was designed in 1982 by Robin Nicholas and Patricia Saunders for Monotype Typography. Monotype is the current (compatible with Helvetica) and Courier New (compatible with Courier). One should understand "compatible" to mean two things: first, that the fonts are similar to look at, and second, very importantly, the fonts have the same character widths so can be used to typeset the same documents without reflowing the text. (The disjunction of the names, particularly between Arial and Helvetica, led some to believe there was a general problem of having to determine an "equivalent" Apple or PostScript font whenever a particular Windows font was called for, or vice versa. However, while the character outlines themselves are different, the styles and weights have been made similar enough that the average user is unable to tell the fonts apart.)
Microsoft and Monotype technicians used TrueType's hinting 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 In digital signal processing, spatial anti-aliasing is the technique of minimizing the distortion artifacts known as aliasing when representing a high-resolution image at a lower resolution. Anti-aliasing is used in digital photography, computer graphics, digital audio, and many other applications, which smooths the edges of fonts at the expense of a slight blurring, and more recently subpixel rendering Subpixel rendering is a way to increase the apparent resolution of a computer's liquid crystal display by rendering pixels to take into account the screen type's physical properties. It takes advantage of the fact that each pixel on a color LCD is actually composed of individual red, green, and blue subpixel stripes to anti-alias text with greater (the Microsoft implementation goes by the name ClearType ClearType is a trademark for Microsoft's implementation of subpixel rendering technology. ClearType attempts to improve the appearance of text on certain types of computer display screens by sacrificing color fidelity for additional intensity variation. This trade-off is asserted to work well on LCD flat panel monitors), which exploits the pixel structure of TFT LCD Thin film transistor liquid crystal display is a variant of liquid crystal display (LCD) which uses thin-film transistor (TFT) technology to improve image quality (e.g., addressability, contrast). TFT LCD is one type of active matrix LCD, though all LCD-screens are based on TFT active matrix addressing. TFT LCDs are used in television sets, based displays to increase the apparent resolution of text. Microsoft has marketed these technologies particularly heavily, and they 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 of Microsoft Corporation in 1996 when it merged support of the Adobe Adobe Systems Incorporated (NASDAQ: ADBE) is an American computer software company headquartered in San Jose, California, USA. The company has historically focused upon the creation of multimedia and creativity software products, with a more-recent foray towards rich Internet application software development Type 1 glyph outlines.
One can embed TrueType fonts in Office. [2]
TrueType today
Macintosh and Windows
TrueType has long been the most common format for fonts on Mac OS Mac OS is the trademark-protected name for a series of graphical user interface-based operating systems developed by Apple Inc. for their Macintosh line of computer systems. The Macintosh user experience is credited with popularizing the graphical user interface. The original form of what Apple would later name the "Mac OS" was the and Windows Microsoft Windows is a series of software operating systems and graphical user interfaces produced by Microsoft. Microsoft first introduced an operating environment named Windows in November 1985 as an add-on to MS-DOS in response to the growing interest in graphical user interfaces . Microsoft Windows came to dominate the world's personal, although both 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 of Microsoft Corporation extension to TrueType (since Mac OS X Mac OS X is a series of Unix-based operating systems and graphical user interfaces developed, marketed, and sold by Apple Inc. Since 2002, Mac OS X has been included with all new Macintosh computer systems. It is the successor to Mac OS 9, the final release of the "classic" Mac OS, which had been Apple's primary operating system since 198 10.0 and Windows 2000 Windows 2000 is a line of operating systems produced by Microsoft for use on personal computers, business desktops, laptops, and servers. Released on 17 February 2000, it was the successor to Windows NT 4.0, and is the final release of Microsoft Windows to display the "Windows NT" designation. It was succeeded by Windows XP for desktop). 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 Mac OS X 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 attempts to create an independent implementation of the TrueType standard (as well as other font standards in FreeType 2). FreeType is included in many Linux Linux refers to the family of Unix-like computer operating systems using the Linux kernel. Linux can be installed on a wide variety of computer hardware, ranging from mobile phones, tablet computers and video game consoles, to mainframes and supercomputers. Linux is predominantly known for its use in servers; in 2009 it held a server market share distributions.
There are potential patent infringements in FreeType 1 because parts of the TrueType hinting virtual machine were patented A patent is a set of exclusive rights granted by a state (national government) to an inventor or their assignee for a limited period of time in exchange for a public disclosure of an invention by Apple, a fact not mentioned in the TrueType standards. (Patent holders who contribute to standards not published by a major standards body such as ISO The International Organization for Standardization , widely known as ISO (pronounced /ˈaɪsoʊ/ EYE-soe), is an international-standard-setting body composed of representatives from various national standards organizations. Founded on 23 February 1947, the organization promulgates worldwide proprietary industrial and commercial standards. It has are not required to disclose the scope of their patents.) FreeType 2 includes an automatic hinter that analyzes glyph A glyph is an element of writing. It is a slightly vague term, but a more precise definition might be an individual mark on paper or another written medium that contributes to the meaning of what is written there. A grapheme is made up of one or more glyphs shapes The shape of an object located in some space is the part of that space occupied by the object, as determined by its external boundary – abstracting from other properties such as colour, content, and material composition, as well as from the object's other spatial properties (position and orientation in space; size) and attempts to generate hints automatically, thus avoiding the patented technology.[3] The automatic hinter generally improves the appearance of free or cheap fonts, for which hinting is often either nonexistent or automatically generated, but it can degrade the appearance of professional hand-hinted fonts, and does not work well (or at all) for non-Western text that requires a different approach to hinting. As a result, some users choose to enable the patented hinting technology.
As of May 2010, all patents related to bytecode hinting have expired worldwide, and FreeType 2.4 now enables these features by default.
Technical notes
Outlines
Quadratic Bézier splines are defined by on-curve and off-curve points.The outlines of the characters (or glyphs A glyph is an element of writing. It is a slightly vague term, but a more precise definition might be an individual mark on paper or another written medium that contributes to the meaning of what is written there. A grapheme is made up of one or more glyphs) in TrueType fonts are made of straight line segments and quadratic Bézier curves In the mathematical field of numerical analysis, a Bézier curve is a parametric curve important in computer graphics and related fields. Generalizations of Bézier curves to higher dimensions are called Bézier surfaces, of which the Bézier triangle is a special case. These curves are mathematically simpler and faster to process than cubic Bézier curves, which are used both in the PostScript-centered world of graphic design 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.[4]
Hinting language
TrueType systems include a virtual machine that executes programs inside the font, processing the "hints" of the glyphs. These distort the control points which define the outline, with the intention that the rasterizer produces fewer undesirable features on the glyph. Each glyph's hinting program 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 hinting language does offer the other prerequisites of programming languages: conditional branching (IF statements), looping 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 hints are the lowest level control, moving a control point at just one pixel size.
Good TrueType glyph programming techniques are meant to do as much as possible using variables defined just once in the whole font (e.g., stem widths, cap height, x-height). 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.
Making a very well-hinted TrueType font remains a significant amount of work, despite the increased user-friendliness of programs for adding hints to fonts compared with the early 1990s. Many TrueType fonts therefore have only rudimentary hints, or have hinting automatically applied by the font editor, with variable end results.
Embedding protection
The TrueType format allows for the most basic type of digital rights management - an embeddable flag that specifies if author allows embedding of the font file into things like PDF files and websites. A simple tool exists to modify this flag.[5]
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 collection of fonts that only use different glyphs on some characters. They were first available in Chinese, Japanese, and Korean versions of Windows, and supported for all regions in Windows 2000 and later.
Mac OS included support of TTC starting with Mac OS 8.5. In Mac OS, TTC has file type ttcf.
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 regular TrueType font, or an Open Type font with TrueType outlines, has a .ttf extension, while a TTC must always have a .ttc extension. An Open Type font with Type 1 outlines must have a .otf extension.
In Mac OS, it is one of several formats called data-fork fonts, as they lack the Mac resource fork.
Suitcase
The suitcase format for TrueType is used on Mac OS. 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 Mac OS X. A suitcase packed into the data-fork-only format has the extension dfont.
PostScript
In the PostScript language, TrueType outlines are handled with a PostScript wrapper as Type 42 for name-keyed, or Type 11 for CID-keyed fonts.
See also
- Embedded TrueType font
- FreeType
- Cleartype
- Typography
- Typeface
- OpenType
- Online office suite
- Unicode, UTF-8, Unicode fonts.
- Uniscribe (Windows multilingual text rendering engine)
- Apple Type Services for Unicode Imaging (New Macintosh multilingual text rendering engine)
- WorldScript (Old Macintosh multilingual text rendering engine)
- Pango (Open source multilingual text rendering engine)
References
- ^ "A Talk with Sampo Kaasila". TrueType Typography. http://www.truetype-typography.com/truetype/sampo.htm. Retrieved 2007-01-10.
- ^ http://word.tips.net/Pages/T000558_Embedding_TrueType_Fonts.html
- ^ [1]
- ^ "Interview: Donald E. Knuth" by advogato [2] [3]
- ^ http://www.derwok.de/downloads/ttfpatch/
External links
- TrueType specification (Apple)
- openfontlibrary.org - free software fonts
- Rendering TrueType fonts to the HTML5 Canvas
Categories: Typesetting | Digital typography | Font formats
Personal tools
- New features
- Log in / create account
Namespaces
- Article
- Discussion
Variants
Views
- Read
- Edit
- View history
Actions
Navigation
- Main page
- Contents
- Featured content
- Current events
- Random article
Interaction
- About Wikipedia
- Community portal
- Recent changes
- Contact Wikipedia
- Donate to Wikipedia
- Help
Toolbox
- What links here
- Related changes
- Upload file
- Special pages
- Permanent link
- Cite this page
Print/export
- Create a book
- Download as PDF
- Printable version
Languages
- Беларуская (тарашкевіца)
- Česky
- Deutsch
- Español
- Français
- 한국어
- हिन्दी
- Hrvatski
- Italiano
- Nederlands
- 日本語
- Polski
- Português
- Русский
- Suomi
- Svenska
- ไทย
- Türkçe
- Українська
- 中文