Making sbit Fonts from fbits

When support was first provided on the Mac OS for East Asian languages, it was necessary to introduce a new format for bitmap fonts. The old 'FOND' and 'NFNT' resource formats were not adequate to the task.

Fonts in the new format are referred to as "fbit" fonts. Sometimes they are called marukan fonts from a Japanese term referring to the circular icon they were given. Basic information on the font continued to reside in the 'FOND' resource in the font suitcase, but the bitmap data itself now resided in an external file with a special icon.

Over the years, a number of 'fbit' formats developed. This made things more difficult both for Apple and for font developers, as it wasn't clear which 'fbit' formats were supported and the exact structure of the various formats was never adequately documented.

Meanwhile, an alternate bitmap format was introduced. It became possible to embed bitmap data directly into a TrueType font as 'sbits'. The sbit data is stored in two tables in the TrueType font, the 'bloc' and 'bdat' tables. This provided a well-documented and maintained way to implement bitmap data for East Asian fonts.

Full information on the format for sbit data is found in the on-line TrueType Reference Manual.

Apple has been encouraging font developers to use sbit fonts rather than fbits for several years, and Apple's own fonts were converted to use sbits. With Mac OS 8.5, Apple reduced the number of fbit formats it supported in the operating system. This makes it more urgent for font developers to do the conversion.

Converting fbits with fbitEnabler

fbit Enabler is a tool provided by Apple Computer to convert fbit fonts to sbits. fbit Enabler only works with fbit formats 0, 3, and 7.

To use fbit Enabler, put the font suitcase and fbit files in the same folder, and install a copy of the font suitcase in the Font folder inside the System. When you run fbit Enabler and the font is sucessfully converted, a new folder with name"Converted xxxx" is created in the folder that contains the font and fbit files. In the new folder, a new suitcase font file and a fbit 42 or 43 "bitmap file" are created. These are dummy fbit files which provide indirect access to the sbits in the TrueType font and are required by versions of the Mac OS prior to 8.5.

fbit Enabler was renamed Font Updater in Mac OS 8.5.

Converting fbits with Marukan Converter

Marukan Converter is a commercial product available from Enfour. It can be used to edit various fbit formats and convert the results to one of the standard formats supported by fbit Enabler. Contact Enfour for more information.The address to contact is:

Richard Northcott, President
Enfour MediaLab, Pty, Ltd.
5-3-14-203 Sendagaya Shibuya-ku
Tokyo 151
Japan
Tel: (03) 5360 8171
Fax: (03) 3355 6923

Editing sbit fonts

Apple provides a tool, SbitEditor, which can be used to examine and edit sbit fonts. Apple's general-purpose TrueType font editing tool, TrueEdit, can also be used to examine sbit fonts.

Apple font tools can be found at the Apple font tool page.