Inside Macintosh: QuickDraw GX Environment and Utilities /

Chapter 8 - QuickDraw GX Mathematics / QuickDraw GX Mathematics Reference

Constants and Data Types

The Mapping Structure

QuickDraw GX defines a transformation matrix with the gxMapping structure:

struct gxMapping {
   Fixed map[3][3];
};

Field Description

map

A 3 3 array of Fixed numbers whose values determine the translation, scaling, rotation, skewing, and perspective operations that can be applied to two-dimensional data. Although defined as containing only Fixed numbers, the rightmost column of the matrix consists of fract numbers. Furthermore, element [3][3] is commonly set to fract1.

The use of the mapping matrix is described further in the section "Transformation Operations With Mappings" beginning on page 8-12.