backcourt violation

[bbcowboy]

When player A advances the ball with a dribble, he gets to the midcourt line and straddles the line. He receives defensive pressure and goes to the backcourt to then continue advancing the ball to the frontcourt.

Is this a backcourt violation as he was not completely into the front court when he moved sideways and backwards into the backcourt and then on to the frontcourt?

Is the violation related to the relationship of the midcourt line to the ball, to the player's foot or to both feet? Is the line itself in the frontcourt or the backcourt? What if he only touches a part of midcourt line and does not go completely over the line?

Thanks.