Mac OS X: Font file formats

Mac OS X introduces a new font format and adds support for certain font formats used by Microsoft Windows. This article discusses the formats and the implications for users.

Data Fork Suitcase Format

One of the innovations offered by Mac OS X is that font suitcases can be completely stored in a file's data fork. All of the resource fork's data is stored in the data fork, which allows more efficient access to font data as well as the ability to copy font suitcases to and from file systems that do not recognize resource forks.

The data fork suitcase format is different from the data fork TrueType font format used by Microsoft Windows. Data fork suitcases contain all of the resources associated with a Macintosh font, including 'FOND' and 'NFNT' resources, which are used with QuickDraw Text.

Data fork suitcases must have the filename extension ".dfont." They may optionally be given the file type "dfon."

Microsoft Windows Font Formats

Mac OS X also works with font formats used by Microsoft Windows. These fonts have all their data in the data fork and do not have the additional resources found in Macintosh fonts. Mac OS X works with these font formats:

• TrueType fonts (with the extension .ttf)
• TrueType collections (with the extension .ttc)
• OpenType fonts (with the extension .otf)

Older Macintosh Fonts

Font suitcases used by Mac OS 9 and earlier that contain TrueType fonts continue to work with Mac OS X. No revision or conversion is necessary. Font suitcases containing only bitmap fonts will be available in Classic applications but not in Mac OS X applications.

Additional information

(The following information is from the Mac OS X 10.3: Fonts Technology Brief.)

Mac OS X delivers industry-leading support for popular font formats:

• PostScript Type 1 (with double-byte support). Adobe PostScript fonts launched the desktop publishing industry and are used today by publishers, corporations, and government agencies for high-quality output to laser printers, imagesetters, and platesetters. Each PostScript font requires two files, one for the screen and one for use by the printer's RIP (raster image processor). Mac OS X is the only operating system that provides native PostScript Type 1 font support.
• OpenType. OpenType fonts (extension .otf) can contain 65,000 different glyphs, so type can be set in non-Roman languages such as Japanese, Chinese, and Korean. There are Macintosh- and Windows-specific OpenType formats; Mac OS X supports both.
• TrueType. TrueType fonts (extension .ttf) are typically used in home and office environments. A single file contains both screen and printer font information. Mac OS X supports both Macintosh- and Windows-specific TrueType formats.
• Multiple Master. This special type of PostScript font allows variation of one or more font parameters (such as weight) to create a large number of custom styles, also known as instances. Mac OS X can activate already created instances of Multiple Master fonts.

Important: Information about products not manufactured by Apple is provided for information purposes only, and does not constitute Apple's recommendation or endorsement. Please contact the vendor for additional information.