The
make-transform
function returns a new transform object initialized according to the optional args. The default args make the unit transform.
Default values are as follows: a and d are 1; b , c , e , and f are 0. The transform matrix is
a b 0
c d 0
e f 1
for generalized two dimensional points of the form
(x y 1)
.
This transform will cause rotation by pi/4 radians:
(let ((s (sin (/ pi 4)))
(c (cos (/ pi 4))))
(gp:make-transform c s (- s) c 0 0))
CAPI Reference Manual - 15 Dec 2011