10. Keeping the paddle in

Here is the code I have for moving the paddle with the keyboard:

def handle_keydown_events(ev):
    global pause, _id
    if ev.keyCode == 37:   # left arrow
        paddle.dx = - abs(paddle.dx)
        paddle.move()
    if ev.keyCode == 39:   # right arrow
        paddle.dx = abs(paddle.dx)
        paddle.move()
    # more code follows for the other keys

Note

Beginners often become too attached to code that “works” or spend too much time thinking about how to write the “best” code before actually writing some code. Often, a very productive approach is to write something that “works” as a prototype and be ready to replace it later.

The problem with this approach is that the motion of the paddle is not smooth. However, it does the job for now, except that the paddle can go out of bounds. Time to do something like we did for the ball.

Your turn

Write a function keep_paddle_in() that ensures that the paddle never gets out of the canvas. Note that the paddle should not “bounce” off the edges of the screen. You need to find a good place to call this function.

To help you avoid “cheating” by looking at my code, I will end this tutorial page here; my version of the code with a brief explanation will come out next.