Smart Font Features
Scheherazade provides alternate glyphs for a number of characters. These are implemented in 3 different ways (OpenType, Graphite and TypeTuner Web) for support in different applications and rendering systems. Ideally the selection of these font features is done in application programs, but many applications do not yet support this functionality. In response to this lack of support for features, a program called TypeTuner (command line version: TypeTuner and web-based version: TypeTuner Web) allows users to create derivative fonts with their own feature settings based on the needs of a local project or region.
These features are documented in this document:
The User-selectable font features are demonstrated using .woff support on this page: Scheherazade Features Demo.
Language-specific features are generally turned on by selecting text in an application and setting the language. In English, you can select English UK or English US and different spelling rules are applied depending on which one is selected. The same is true for other languages. Besides spelling rules, setting a language can also affect font behavior. Scheherazade has a set of default behaviors. However, it also contains OpenType and Graphite smart font code to change the behavior based on language selection. In Scheherazade there are language-specific features for four languages. These are Kurdish, Rohingya, Sindhi and Urdu.
The language-specific features that are in the font are described in the Scheherazade Font Features Guide and are illustrated in the table below:
Unfortunately, the UI needed to access the language-specific behavior is not yet present in many applications. Microsoft Word 2013 supports language-specific behavior for Sindhi and Urdu (but not Kurdish or Rohingya). LibreOffice supports three of the languages (all but Rohingya) supported by Scheherazade. Some Harfbuzz-based apps, e.g., XeTeX, can access language-specific behavior.
In addition to the language-specific variants shown above, there are other Arabic character shape differences in the Arabic script. These can be accessed by using Graphite features or the OpenType Character Variants feature. The document below can be downloaded in order to see all the user-selectable font features that are available in the font. The feature names, feature ids, settings and examples are provided.
U+06DD (End of Ayah) and subtending marks (U+0600..U+0605)
These Arabic characters are intended to enclose or hold one or more digits.
Specific technical details of how to use them are discussed in the Arabic fonts FAQ — Subtending marks.
Additionally, Scheherazade includes two simplified alternates for U+06DD ARABIC END OF AYAH under the Stylistic Alternates (salt) feature, but at this time we know of no OpenType-based applications that can access these. The two alternates are also available through the Character Variants feature.
Customizing with TypeTuner
For applications that do not make use of Graphite or the OpenType Stylistic Sets or Character Variants features, you can now download fonts customized with the variant glyphs you choose. Read the Scheherazade Font Features Guide, visit TypeTuner Web, then to choose the variants and download your font.