rotate

rotation of a set of points

Calling Sequence

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

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.

Sample

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