RF = rotatef(F, THETA) rotates the vector/scalar field(s) F about the
center through the angle THETA in the trigonometric direction (THETA is
given in radians). Points which have antecedent from outside the
original field are filled with 0. The new field RF is an
interpolation of the original field F on the new grid.
RF = rotatef(F, THETA, X0, Y0) rotates about the center specified by
(X0, Y0), in physical units. The center does not need to be inside the
field. Specify rotatef(F, THETA, X0, Y0, 'mesh') to give the center
in mesh units instead of physical units.
RF = rotatef(...,'trunc') keeps only the largest rectangular area
(with the aspect ratio kept constant) containing only valid (i.e.
nonzero) elements. LIMITATION: This option works only for rotation
about the center - do not use it for any other center!
If no output argument, the result is displayed by showf.
rotatef is useful for correcting vector/scalar fields obtained from
skewed images (e.g. misaligned camera).