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Doulos SIL — Documentation

NRSI staff, 2009-05-27; 36026 reads

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Table of Contents for this web page:

    System requirements
    Features of the font
    Supported character ranges
    Conversion
    Keyboarding

System requirements

The Doulos SIL font is designed to work on systems and with applications that provide support for TrueType fonts and for Unicode character encoding. This includes Microsoft Windows® 9x or greater, as well as recent versions of the Mac OS (version 9.0 and later), and also some implementations of Unix / Linux (TrueType font support on Unix and Linux may depend upon the particular applications in use). On some systems (true, at least, of 32-bit Windows), it can also be used with older applications that use legacy, industry-standard, 8-bit character encodings.

The preceding characterization of system requirements describes the minimum needed to display characters. Realizing the full capabilities of this font involves additional requirements. The first release of this font was designed to work with either of two advanced font technologies, Graphite or OpenType; beginning with release 4.0.12, it also contains AAT tables to offer selection of alternate glyphs on Mac OS X. To take advantage of the advanced typographic capabilities of this font, you must be using applications that provide an adequate level of support for Graphite and OpenType.

Features of the font

The Doulos SIL font contains near-complete coverage of all the characters defined in Unicode 5.1 for Latin and Cyrillic. In total, over 4,600 glyphs are included, providing support for over 1,900 characters as well as a large number of ligated character sequences (e.g., contour tone letters used in phonetic transcription of tonal languages).

In addition, alternately-designed glyphs are also provided for a number of characters for use in particular contexts. The glyphs are accessible in applications that support advanced font technologies, specifically the Graphite or OpenType technologies. These technologies are also utilized to provide automatic positioning of diacritics relative to base characters in arbitrary base+diacritic combinations (including combinations involving multiple diacritics).

Some important issues with respect to Unicode need to be borne in mind. Unicode is a character encoding and not a glyph encoding. Thus you should endeavor to use the character that reflects your character needs rather than finding a glyph that looks right and using its character code. Thus, for example, there is only one code for CAPITAL ENG (U+014A), although there are 4 different glyph shapes for this character in use around the world. Therefore it is necessary to use other means, such as user-selectable font features, to ensure that your document displays the right glyph for the character that you are anticipating. The advanced typographic capabilities mentioned above provide this very capability.

See also “How do I use a feature?”

Advanced typographic capabilities

This font supports various advanced typographic capabilities using the Graphite, OpenType, or AAT font technologies.

• Automatic conversion of sequences of pitch letters (U+02E5..U+02E9 and U+A712..U+A716) into ligatures.
• Automatic fi-type ligatures.
• Auto placement of diacritics to a sufficient level of stacking.
• Auto placement of double-width diacritics (U+035C..U+0362) according to heights and depths of adjacent clusters (in Graphite only)
• Vietnamese diacritic placement handling (enabled via a user-selectable font feature).

The automatic placement of diacritics is supported for data that may or may not be canonically ordered (as defined by the  Unicode Standard). This should normally be the responsibility of application software and text-processing resources (such as input methods), however, and not the user.

These capabilities are available in any application that supports the Graphite technology. They are also available via the OpenType technology, though this requires applications that provide a sufficient level of support for OpenType features. (See System Requirements.) With AAT applications, only limited combinations of base characters and diacritics will work correctly; beyond the supported set of combinations, diacritic placement may be inferior.

User-selectable font features

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. The document was produced with Graphite OpenOffice.

Font Features for Doulos SIL 4.106 Lorna A. Priest, 2009-10-27 Download "DoulosSILVariants4.106.pdf", Acrobat PDF document, 873KB [17861 downloads]

AAT

This font includes AAT tables that provide limited diacritic placement, automatic ligatures, and selection of alternate glyphs in applications that fully support Unicode and Apple Advanced Typography. However, diacritic placement for arbitrary base+diacritic combinations may be less than ideal because of limitations in the AAT technology.

The user-selectable font features for choosing alternate glyph shapes are typically accessed via the Typography palette, available in applications such as TextEdit via a pop-up menu in the Fonts panel. (The user interface may differ in other applications, and not all of the user-selectable font features are supported in the AAT part of the font.)

Supported character ranges

This font supports over 1,900 characters from the Unicode 5.1 standard as well as over 229 Private Use Area (PUA) characters. In total, over 4,600 glyphs are included, supporting stylistic alternates for a number of characters as well as a large number of ligated sequences (e.g., contour tone letters used in phonetic transcription of tonal languages). The following character ranges constitute the list of characters supported by this font:

Supported character ranges

Private-use (PUA) characters

There are 230 private-use characters that are supported in this font. These conform to SIL International’s corporate registry for usage of the Unicode private-use areas. Characters which are not yet in Unicode are shown below.

Specials

Combining Marks

Modifier Letters

Latin

Cyrillic

Deprecated SIL Corporate PUA characters Lorna A. Priest, 2012-02-07; 8513 reads

These PUA characters have been added to Unicode and are being deprecated. This page lists those PUA characters along with the appropriate Unicode codepoints. Please use the Unicode codepoint instead of the PUA codepoint. Our SIL Unicode Roman fonts will continue to support the PUA codepoint for backwards compatibility purposes.

Conversion

In order to use this font with existing data that was created for use with fonts developed using the Encore Fonts system, or with custom-encoded fonts created by other means, it is necessary to re-type or convert data to produce data that is encoded in conformance with the Unicode Standard. TECkit is one program that can be used for character encoding conversion. TECkit allows users to write their own custom conversion mappings.

The TECkit package is available for download from SIL’s TECkit Web site.

Some TECkit mapping files have already been created for some of the more widely used SIL legacy fonts.

The Unicode 4.1 standard included 139 characters that were previously allocated to codepoints in the Private Use Area by SIL's PUA committee. The Unicode 5.0 standard includes 45 characters that were previously allocated to codepoints in the Private Use Area by SIL's PUA committee. The Unicode 5.1 standard includes 17 characters that were previously allocated to codepoints in the Private Use Area by SIL's PUA committee.

All processes (input methods, mappings) that create Unicode data should be revised to generate the proper Unicode values instead of PUA codes.

If you have data that contains these PUA codes, it should be updated by replacing each PUA character with its official Unicode counterpart. This will facilitate data interchange and the use of standard fonts and software.
SIL PUA to Unicode 5.1 Mapping is provided for converting your data.

Keyboarding

The ability to obtain full benefits of this font is also dependent upon having means for Unicode character input. This package does not include keyboard input methods. Most current operating systems provide keyboard input methods for a number of different languages that have writing systems based on the Roman or Cyrillic scripts. Various means may be available for different operating-system platforms to create additional input methods for other languages. Some of these are listed here: Some tools and resources for character input.

Backlinks (20 most popular; affiliated sites and popular search engines removed)

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