How to do it…

1. Imports: First we will import the required Pygame modules. If Pygame is installed properly, we should get no errors:

   import pygame, sys
   from pygame.locals import *

2. Initialization: We will initialize Pygame by creating a display of 400 by 300 pixels and setting the window title to Hello world:

   pygame.init()
   screen = pygame.display.set_mode((400, 300))
   pygame.display.set_caption('Hello World!')

3. The main game loop: Games usually have a game loop, which runs forever until, for instance, a quit event occurs. In this example, we will only set a label with the text Hello world at coordinates (100, 100). The text has a font size of 19, red color, and falls back to the default font:

   while True:
   sys_font = pygame.font.SysFont("None", 19)
   rendered = sys_font.render('Hello World', 0, (255, 100, 100))
   screen.blit(rendered, (100, 100))
   for event in pygame.event.get():
   if event.type == QUIT:
   pygame.quit()
   sys.exit()
   pygame.display.update()
   
   

   We get the following screenshot as the end result:

   

   The following is the complete code for the Hello World example:

   import pygame, sys
   from pygame.locals import *
   pygame.init()
   screen = pygame.display.set_mode((400, 300))
   pygame.display.set_caption('Hello World!')
   while True:
   sysFont = pygame.font.SysFont("None", 19)
   rendered = sysFont.render('Hello World', 0, (255, 100, 100))
   screen.blit(rendered, (100, 100))
   for event in pygame.event.get():
   if event.type == QUIT:
   pygame.quit()
   sys.exit()
   pygame.display.update()

How it works…

It might not seem like much, but we learned a lot in this recipe. The functions that passed the review are summarized in the following table:

Drawing with Pygame

Before we start creating cool games, we need an introduction to the drawing functionality of Pygame. As we noticed in the previous section, in Pygame we draw on the Surface objects. There is a myriad of drawing options—different colors, rectangles, polygons, lines, circles, ellipses, animation, and different fonts.

How to do it…

The following steps will help you diverge into the different drawing options you can use with Pygame:

1. Imports: We will need the NumPy library to randomly generate RGB values for the colors, so we will add an extra import for that:

   import numpy 

2. Initializing colors: Generate four tuples containing three RGB values each with NumPy:

   
   colors = numpy.random.randint(0, 255, size=(4, 3))

   Then define the white color as a variable:

   WHITE = (255, 255, 255)

3. Set the background color: We can make the whole screen white with the following code:

   screen.fill(WHITE)

4. Drawing a circle: Draw a circle in the center with the window using the first color we generated:

   pygame.draw.circle(screen, colors[0], (200, 200), 25, 0)

5. Drawing a line: To draw a line we need a start point and an end point. We will use the second random color and give the line a thickness of 3:

   pygame.draw.line(screen, colors[1], (0, 0), (200, 200), 3)

6. Drawing a rectangle: When drawing a rectangle, we are required to specify a color, the coordinates of the upper-left corner of the rectangle, and its dimensions:

   pygame.draw.rect(screen, colors[2], (200, 0, 100, 100))

7. Drawing an ellipse: You might be surprised to discover that drawing an ellipse requires similar parameters as for rectangles. The parameters actually describe an imaginary rectangle that can be drawn around the ellipse:

   pygame.draw.ellipse(screen, colors[3], (100, 300, 100, 50), 2)

The resulting window with a circle, line, rectangle, and ellipse using random colors:

The code for the drawing demo is as follows:

import pygame, sys
from pygame.locals import *
import numpy
pygame.init()
screen = pygame.display.set_mode((400, 400))
pygame.display.set_caption('Drawing with Pygame')
colors = numpy.random.randint(0, 255, size=(4, 3))
WHITE = (255, 255, 255)
#Make screen white
screen.fill(WHITE)
#Circle in the center of the window
pygame.draw.circle(screen, colors[0], (200, 200), 25, 0)
# Half diagonal from the upper-left corner to the center
pygame.draw.line(screen, colors[1], (0, 0), (200, 200), 3)
pygame.draw.rect(screen, colors[2], (200, 0, 100, 100))
pygame.draw.ellipse(screen, colors[3], (100, 300, 100, 50), 2)
while True:
for event in pygame.event.get():
if event.type == QUIT:
pygame.quit()
sys.exit()
pygame.display.update()

Summary

Here we saw how to create a basic game to get us started. The game demonstrated fonts and screen management in the time-honored tradition of Hello world examples.

The next section of drawing with Pygame taught us how to draw basic shapes such as rectangles, ovals, circles, lines, and others. We also learned important information about colors and color management.

Resources for Article :

Further resources on this subject:

• Using Execnet for Parallel and Distributed Processing with NLTK [Article]
• TortoiseSVN: Getting Started [Article]
• Python 3 Object Oriented Programming: Managing objects [Article]