CREATELINE Create a straight line from 2 points, or from other inputs.

   Line is represented in a parametric form : [x0 y0 dx dy]
   x = x0 + t*dx
   y = y0 + t*dy;


   L = createLine(p1, p2);
   Returns the line going through the two given points.
   
   L = createLine(x0, y0, dx, dy);
   Returns the line going through point (x0, y0) and with direction
   vector(dx, dy).

   L = createLine(LINE);
   where LINE is an array of 4 values, creates the line going through the
   point (LINE(1) LINE(2)), and with direction given by vector (LINE(3)
   LINE(4)). 
   
   L = createLine(THETA);
   Create a polar line originated at (0,0) and with angle THETA.

   L = createLine(p, THETA);
   Create a polar line originated at p and with angle THETA.

   L = createLine(RHO, THETA);
   Create a polar line with normal theta, and with min distance to origin
   equal to rho. rho can be negative, in this case, the line is the same
   as with CREATELINE(-rho, theta+pi), but the orientation is different.


   Note: in all cases, parameters can be vertical arrays of the same
   dimension. The result is then an array of lines, of dimensions [N*4].


   See also:
   lines2d, createEdge, createRay

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

Package: matgeom