This module will be removed in a future release. Please use 
\verb+fzrt+ instead.

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x
This module performs a rotation of angle $a$ on a Fimage $u(i,j)$, using
a bilinear interpolation $\tilde{u}(x,y)$ of $u(i,j)$ to compute the rotated 
image
$$u'(i,j) = \tilde{u}(\;i \cos a - j \sin a\;,\;i \sin a + j \cos a\;).$$
Since the rotated image must be included in a rectangular window, a 
black background (grey level $0.0$) is set on the undefined parts of
the rotated image. This background value can be modified through the 
$-b$ option.

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Last, notice that that two successive rotations of angles $a$ and $a'$ 
are {\em not} equivalent to a single rotation of angle $a+a'$, due to
the the discrete representation of the images.

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NB: Calling this C-subroutine with in=out is not possible
