Arguments: position matrix
Transforms the given position with the supplied matrix, which is a 2 by 2 array (or larger 2-dimensional array -- extra cells of the array are ignored). Even if the elements of matrix are floats, the returned position will have rounded whole number components. The transform works as follows:
xnew = A(0,0)*xold + A(0,1)*yold ynew = A(1,0)*xold + A(1,1)*yold
For example:
(setq ar (make-array '(2 2)
:initial-contents '((5.0 2.0) (3.0 1.0))))
(setq p1 (make-position 7 10)
(position-transform p1 ar)
returns
#.(make-position 55 31) ; = 5*7 + 2*10, 3*7 + 1*10
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Created 2000.10.5.