rotate(2)

NAME
rotate - geometric rotation of a set of points

CALLING SEQUENCE
[xy1]=rotate(xy,[theta,orig])

PARAMETERS

xy,xy1
    : matrices of size (2,.)

theta
    : real (angle en radian) , (default value=0)

orig
    : center of the rotation [0;0] if omitted

DESCRIPTION
xy1(:,i) = M(theta) *xy(:,i) + orig where M stands for a rotation matrix of angle theta

EXAMPLE
xsetech([0,0,1,1],[-1,-1,1,1])
xy=[(0:0.1:10);sin(0:0.1:10)]/10;
for i=2*%pi*(0:10)/10,[xy1]=rotate(xy,i);
	xpoly(xy1(1,:),xy1(2,:),"lines")
end