REVERSELINE Return same line but with opposite orientation.

   INVLINE = reverseLine(LINE);
   Returns the opposite line of LINE.
   LINE has the format [x0 y0 dx dy], then INVLINE will have following
   parameters: [x0 y0 -dx -dy].

   See also:
   lines2d, createLine

   ---------
   author : David Legland 
   INRA - TPV URPOI - BIA IMASTE
   created the 20/01/2004.

Package: matgeom