The purpose of the above applet is to show the force on a current loop in a magnetic field.
$\vec{F}= I d\vec{\ell}\times \vec{B}$

The magnetic field line is a by product.

So all the magnetic field line pass throught the current (event when magnet is off-axis).
That is the reason , the field line starts from the current loop.

If you just need to show magnetic field lines for a bar magnet, I can modify the code to create another simulation:
1. remove current loop and other.
2. let field line starts from N pole.