Question

Using MatLab, I know how to create a line segment connecting two points using this code:

line([0 1],[0 1])

This draws a straight line segment from the point (0,0) to the point (1,1).

What I am trying to do is continue that line to the edge of the plot. Rather than just drawing a line between these two points I want to draw a line through those two points that spans the entire figure for any set of two points.

For this particular line and a x=-10:10, y=-10:10 plot I could write:

line([-10 10], [-10 10]);

But I would need to generalize this for any set of points.

Answer 1

What about

  function = long_line(X,Y,sym_len)
       dir = (Y-X)/norm(Y-X);
       Yp = X + dir*sym_len;
       Xp = X - dir*sym_len;
       line(Xp,Yp);
  end

being sym_len one half of the expected length of the plotted line around X?