OpenType is a scalable computer font format initially developed by Microsoft, later joined by Adobe Systems. OpenType was first announced in 1996, with significant number of OpenType fonts starting to ship in 2000-2001. Adobe completed conversion of their entire font library to OpenType around the end of 2002. As of early 2005, there are over 7,000 fonts available in OpenType format, with Adobe's library making up for about 1/3 of the total.

OpenType was intended by Microsoft to be the successor to the TrueType font format developed by Apple Computer and licensed by Microsoft. Microsoft tried to license Apple's advanced typography technology, "GX Typography," and upon being refused turned to develop its own technology dubbed "TrueType Open" and later on "OpenType". Adobe Systems joined the OpenType camp later, adding support for its PostScript Type 1 fonts.

OpenType uses the general structure of a TrueType font, but adds several unique options which enhance the fonts typographical abilities. An OpenType font can include either TrueType outlines or PostScript-style outlines (though stored in the CFF/Type 2 format).

OpenType has several distinctive features:

• the font encoding is based on Unicode and can support any language (or multiple languages at once)
• OpenType fonts can have up to 65,536 glyphs
• fonts can have advanced typographic features, which allow proper typographic treatment of complex languages, and advanced typographic effects for simpler languages, such as English.

Compared with Apple Computer's "GX Typography" now called Apple Advanced Typography, or AAT, OpenType is slightly inferior with most typographical options, but offers superior language-related options and support.

From a font developer's perspective, OpenType is much easier to develop for than GX was. First, the simple declarative substitutions and positioning of OpenType are much simpler to understand and code for than GX's state tables. Second, Adobe's strategy of licensing at no charge the source code developed for its own font development allowed third-party font editing applications such as FontLab and FontMaster to relatively easily add support. Although Adobe's text-driven coding support is not as visual as Microsoft's separate tool, VOLT (Visual OpenType Layout Tool), the integration with the tools being used to make the fonts has been well received.

OpenType support may be divided into several categories: virtually all applications and most operating systems work with OpenType fonts just as well as other, older formats. What is of particular interest is: extended language support through Unicode, support for "complex" languages such as Arabic and the Indic languages, and advanced typographic support for western languages such as English.

As of early 2005, extended language support via Unicode for both OpenType and TrueType is present in most Windows applications (including Microsoft Office, Publisher and most Adobe applications), and many Mac OS applications, especially Apple's own such as TextEdit and Keynote.

OpenType support for complex languages has so far mainly appeared in Microsoft applications such as Office and Publisher.

Advanced typographic support for western languages has so far mainly appeared in Adobe applications such as Adobe InDesign, Adobe Photoshop and Adobe Illustrator. However, competitor Quark has announced that they will offer similar support in QuarkXPress 7 (release date not yet known).

OpenType is a registered trademark of Microsoft Corporation.

See also

• 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)

External links

• Adobe main OpenType page: http://www.adobe.com/type/opentype
• The OpenType Specification (Adobe): http://partners.adobe.com/asn/developer/opentype/main.html
• The OpenType Specification (Microsoft): http://www.microsoft.com/typography/otspec/default.htm
• Main Microsoft Typography site: http://www.microsoft.com/typography
• Microsoft information about font development: http://www.microsoft.com/typography/creators.htm