ORTHOGONALLINE Create a line orthogonal to another one through a point.

   PERP = orthogonalLine(LINE, POINT);
   Returns the line orthogonal to the line LINE and going through the
   point given by POINT. Directed angle from LINE to PERP is pi/2.
   LINE is given as [x0 y0 dx dy] and POINT is [xp yp].

   Works also when LINE is a N-by-4 array, or POINT is a N-by-2 array. In
   this case, the result is a N-by-4 array.


 Example
     refLine = createLine([10 10], [30 20]);
     pt = [20 40];
     figure; hold on; axis equal; axis([0 50 0 50]);
     drawLine(refLine, 'lineWidth', 2);
     drawPoint(pt);
     perp = orthogonalLine(refLine, pt);
     drawLine(perp, 'color', 'r');
 
   See also:
   lines2d, parallelLine, intersectLines

   ---------
   author : David Legland 
   INRA - TPV URPOI - BIA IMASTE
   created the 31/10/2003.

Package: matgeom