lively@sunybcs.uucp (Richard S. Lively) (04/08/88)
The question was to represent a shearing transformation as a
sequence of "basic" transformations, not just as single rotation
and a single scale. A sequence that will give the matrix:
(1 0)
(a 1)
is as follows:
R(-PI/4) S(sqrt((1-a)/(1+a)), 1) R(sqrt(1-a), sqrt(1+a))
S((1-a)/sqrt(2(1-a)), 1/sqrt(2(1+a)))
where the notation R(x,y) is a rotation by angle theta with
cos(theta) = x and sin(theta) = y.