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Migrating Data Types from the Font Manager

There are two sets of programming interfaces you can use in Mac OS X that you can use to manage fonts—ATS for Fonts and the Font Manager. This document focuses on using ATS for Fonts, the programming interface designed for font management in Mac OS X. The Font Manager is designed for Mac OS 9 but can be used as a compatibility path from Mac OS 9 to Mac OS X. The Font Manager is discussed in detail in Managing Fonts: QuickDraw and Font Manager Reference.

When you migrate code from the Font Manager to ATS for Fonts, keep in mind the difference between the data types used in each API. Although there are parallels between the data types used to reference fonts and font families in the two programming interfaces, the base types are different. The ATSFontFamilyRef data type is an opaque 32-bit value while the FMFontFamily data type is a signed 16-bit integer, so you should avoid type casting or implicit type promotion when working with these data types. Instead, use the conversion functions defined for the font family references by the QuickDraw framework to protect your software from any changes or differences in the way these two data types are generated.

The FMFont and ATSUFontID data types are equivalent so you can use them interchangeably with the functions provided by the Font Manager and ATSUI in the QuickDraw framework. However, you must use the functions listed in Table 2-3 to convert between Font Manager and ATS for Fonts data types. See Font Manager Reference for more information on these functions.

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