OpenType

OpenType is a primitive, later developed by Microsoft along with Adobe fonts with a concept for this specially developed font format. It was released in 1996 and since 2000 a greater number OpenType fonts was put on the market.

Comparison with TrueType and PostScript

The OpenType format overcomes limitations essential to the widespread and TrueType font formats ( PostScript ) Type 1 Font:

Characteristics

OpenType fonts are available in two versions (English flavors ):

• TrueType - flavored OpenType ( ttf file extension. ) And
• PostScript - flavored OpenType ( otf file extension. ).

The expression refers to the type of storage of data for the signature curves, either in TrueType format (quadratic splines ) or in the PostScript CFF format Compact Font Format ( cubic splines) are embedded in the OpenType font. These allow TrueType -flavored OpenType fonts also assigning multiple codes to the same glyph, eg as A ( U 0041 ), Alpha ( U 0391 ) and Cyrillic A ( U 0491 ).

The specific OpenType features are implemented generically additionally installed in the font tables.

Although previously a full support of OpenType features can be found on any platform, the writings generally work at least as Unicode fonts, which may include a character set of up to 65536 glyphs, as already newer versions of TrueType and PostScript ( CFF format ). The use of the OpenType features is usually (eg desktop publishing programs ) allows by means of suitable applications.

As part of the migration of security portfolios of the formats TrueType and PostScript towards OpenType major font vendors have implemented not only OpenType features, but also, if sooner, separately managed but interrelated writings (eg, a version with small caps, old style figures or foreign-language fonts) integrated into the associated OpenType font. In order to characterize the resulting differences in character size of the various OpenType fonts, the font manufacturer minimum font sizes have defined and expressed using abbreviations in the name of the font. There is a standard font size ( OpenType ), a value suitable for the professional ( typographical ) application character set expansion ( OpenType Pro) and designed for international communication character set ( OpenType Com). These are heavily marketed differently depending on the manufacturer.

Examples

Special forms for capitalization

Language-specific variants

Other variants

While it is merely typographical variants in the examples, there are many situations in which the use of a so-called smart font technology, how it is possible through the OpenType format for the creation of texts is essential. Almost all derived from the Brahmi script writing systems such as Devanagari, Tibetan, Khmer and Tamil know complex rules for the use of position -related letterforms and ligatures. Urdu can be written from top right to bottom left with related letter word. The correct placement of diacritical marks and their theoretically unlimited stacking above and below letters is possible with OpenType. Due to the technical possibilities of OpenType receives not least the font developers a significantly expanded freedom of design.

Dissemination

Most reputable providers have largely changed their writings on the OpenType format. Support for OpenType possibilities of current applications but currently can (January 2006) a lot to be desired. Microsoft Office in particular supports the functions for so-called complex writing systems, bidirectional writing, and for the Latin alphabet after all the correct diacritics placement. In addition, professional programs of Adobe, the program QuarkXPress 7, AbiWord and the Classical Text Editor replacements offer of characters such as in the examples shown above on Windows and Mac OS X. The programs of the Adobe Creative Suite (Photoshop, Illustrator, InDesign) permit no later than since version CS3, the use of OpenType features. They are found in the Palette menu to the font properties. Automatic replacement of ligatures and use of Positionalformen (variants of letters in the word or at the end ) can be there also dismissed.

While Microsoft Word up to version 2007 does not automatically replace a fi writing by the fi ligature, the program can handle from 2010 version with ligatures.

Terms of Use

Although OpenType is a registered trademark of Microsoft, but the technology must be fully transferred to other operating systems. So Apple's Mac OS X supports both PostScript and TrueType and OpenType fonts, and easily portable open source FreeType Project offers developers the ability to take full access to the OpenType features of scriptures and to integrate these into their programs. This benefits increasingly desktop publishing programs from Adobe and Quark Xpress and Linux applications. Furthermore, OpenType support with the program libraries ICU ( International Components for Unicode), Qt and Pango, a byproduct of GTK and GNOME, are integrated into applications.

Other smart font technologies

Except OpenType there are two other writing techniques that are designed for similar advanced typographic possibilities. Their common characteristic is that they also use regular programs except tables, and that to date convenient tools for font developers exist for any of them. Also their support by application software is still much scantier than for OpenType.

• AAT (Apple Advanced Typography ), the oldest smart font technology, is superior with respect to the OpenType typographic possibilities. OpenType is, however, much more versatile. For copyright reasons AAT may not be transferred to other platforms easily.
• Graphite, an open- source project of SIL, was developed for the representation of minority languages. For not yet standardized in Unicode characters one is not rare on the so-called Private Use Area (U E000 - U F8FF ) as their interim solution. The encoded characters there are in Unicode classified as letters ( Lo = Letter, other). Unlike OpenType allows Graphite (as well as AAT) a different treatment of PUA characters, for example as diacritics. For Graphite is Worldpad, a simple text editor available. SILA, an expanded graphites Mozilla browser is in the works; very early versions can be tested. OpenOffice.org ( since version 3.2) and LibreOffice ask Graphite support. Graphite is supported by UNESCO.

List of OpenType fonts with extensive smart font using

• Minion Pro, designed by Adobe as an example for OpenType OTF file
• Linux Libertine, open source, OTF and TTF file