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.TrueType outlines use quadratic Bézier curves.CFF outlines use cubic Bézier curves. 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. The specification germinated at Microsoft, with Adobe Systems also contributing by the time of the public announcement in 1996. Because of wide availability and typographic flexibility, including provisions for handling the diverse behaviors of all the world's writing systems, OpenType fonts are used commonly today on the major computer platforms. OpenType's origins date to Microsoft's attempt to license Apple's advanced typography technology GX Typography in the early 1990s. Those negotiations failed, motivating Microsoft to forge ahead with its own technology, dubbed 'TrueType Open' in 1994. Adobe joined Microsoft in those efforts in 1996, adding support for the glyph outline technology used in its Type 1 fonts. These efforts were intended by Microsoft and Adobe to supersede both Apple's TrueType and Adobe's Type 1 ('PostScript') font formats. Needing a more expressive font format to handle fine typography and the complex behavior of many of the world's writing systems, the two companies combined the underlying technologies of both formats and added new extensions intended to address those formats' limitations. The name OpenType was chosen for the combined technologies, and the technology was announced later that year. Adobe and Microsoft continued to develop and refine OpenType over the next decade. Then, in late 2005, OpenType began migrating to an open standard under the International Organization for Standardization (ISO) within the MPEG group, which had previously (in 2003) adopted OpenType 1.4 by reference for MPEG-4. Adoption of the new standard reached formal approval in March 2007 as ISO Standard ISO/IEC 14496-22 (MPEG-4 Part 22) called Open Font Format (OFF, not to be confused with Web Open Font Format). It is also sometimes referred to as 'Open Font Format Specification' (OFFS). The initial standard was technically equivalent to OpenType 1.4 specification, with appropriate language changes for ISO. The second edition of the Open Font Format was published in 2009 (ISO/IEC 14496-22:2009) and was declared 'technically equivalent' to the 'OpenType font format specification'. Since then, the Open Font Format and the OpenType specification have continued to be maintained in sync. OFF is a free, publicly available standard. By 2001 hundreds of OpenType fonts were on the market. Adobe finished converting their entire font library to OpenType toward the end of 2002. As of early 2005, around 10,000 OpenType fonts had become available, with the Adobe library comprising about a third of the total. By 2006, every major font foundry and many minor ones were developing fonts in OpenType format. Unicode version 3.2 (published in 2002) introduced variation selectors as an encoding mechanism to represent particular glyph forms for characters. Unicode did not, however, specify how text-display implementations should support these sequences. In late 2007, variation sequences for the Adobe-Japan1 collection were registered in the Unicode Ideographic Database, leading to a real need for an OpenType solution. This resulted in development of cmap subtable Format 14, which was introduced in OpenType version 1.5. Unicode version 6.0 introduced emoji encoded as characters into Unicode. Several companies quickly acted to add support for Unicode emoji in their products. Since Unicode emoji are handled as text, and since color is an essential aspect of the emoji experience, this led to a need to create mechanisms for displaying multicolor glyphs.