Raspberry Pi 3 Cookbook for Python Programmers - Third Edition

How it works...

The Python code creates a Tkinter window that contains a Canvas object called the_canvas. We use the bind function here, which will bind a specific event that occurs on this widget (the_canvas) to a specific action or key press. In this case, we bind the <Motion> function of the mouse, plus the click and release of the first mouse button (<ButtonPress-1> and <ButtonRelease-1>). Each of these events are then used to call the mouse1press(), mouse1release(), and mousemove() functions.

The logic here is to track the status of the mouse button using the mouse1press() and mouse1release() functions.

If the mouse button has been clicked, the mousemove() function will check to see whether we are drawing a new line (we set new coordinates ...