rotate

Arguments

xy

matrix of size (2,.).

xy1

matrix of size (2,.).

theta

real, angle in radians; default value is 0.

orig

center of the rotation [xc;yc]; default value is [0;0].

Description

rotate performs a rotation with angle theta:

xy1(:,i) = M(theta) *(xy(:,i) - orig) + orig

where M stands for the corresponding rotation matrix.

Examples

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