This module bitmaps the points of a Fcurves structure on a Cimage.
The points are drawn in black
(grey level 0) on a white (grey level 255) background. 
If the \verb+-s+ option is selected, the curves are 
first translated in order that the upleft corner of the bounding box
is  $(0,0)$~; if not, the points with non-positive 
coordinates are not drawn.
The image is then sized in order to contain all the (remaining) points.
The coordinates of the points of the curves are
rounded to integers using the \verb+nint()+ function. 

