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Inside Macintosh: QuickDraw GX Environment and Utilities /

Chapter 8 - QuickDraw GX Mathematics / About QuickDraw GX Mathematics

Number-Conversion Macros

QuickDraw GX provides a set of predefined macros for the conversion between different fixed-point number formats. This allows you the convenience of accessing the number-conversion formulas as if they were function calls.

Table 8-1 summarizes the number-format conversions that are supported.

Table 8-1 Macro number-format conversions

From number format	To number format
Fixed	fract
Fixed	floating-point
Fixed	integer
fract	floating-point
fract	Fixed
fract	gxColorValue
floating-point	fract
floating-point	Fixed
integer	Fixed
gxColorValue	fract

QuickDraw GX also provides macros that

• round a Fixed number to its nearest integer
• determine the greatest integer that is not greater than a given Fixed number
• use a function to determine the square root of a Fixed number

The use of QuickDraw GX macros is described in the section "Converting Number Formats" beginning on page 8-26. Each macro is described in the section "Number-Conversion Macros" beginning on page 8-36.