Oh right. That's just something Apple recommends in the documentation on CTM transforms in the quartz2d programming guide. I suggest you check it out, though it didn't clear up all of my questions.
Anyway, the missing function just translates degrees into radians, which are what those methods need. Here it is:
Code:
#include <math.h>
static inline double radians (double degrees) {return degrees * M_PI/180;}
