Conventions used

There are a number of text conventions used throughout this book.

CodeInText: Indicates code words in text, database table names, folder names, filenames, file extensions, pathnames, dummy URLs, user input, and Twitter handles. Here is an example:

"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."

A block of code is set as follows:

#!/usr/bin/python3 
# bouncingball.py 
import tkinter as TK 
import time 
 
VERT,HOREZ=0,1 
xTOP,yTOP = 0,1 
xBTM,yBTM = 2,3 
MAX_WIDTH,MAX_HEIGHT = 640,480 
xSTART,ySTART = 100,200 
BALL_SIZE=20 
RUNNING=True 

Any command-line input or output is written as follows:

sudo nano /boot/config.txt

Bold: Indicates a new term, an important word, or words that you see onscreen. For example, words in menus or dialog boxes appear in the text like this. Here is an example: "Click on the Pair button to begin the pairing process and enter the device's PIN."