Page 82 - Programming the Raspberry Pi Getting Started with Python

Figure 8-1 Hello Pygame

This is a very crude example, and it doesn’t have any way of exiting gracefully. Closing the Python
console from which this program was launched should kill it after a few seconds.
Looking at the code for this example, you can see that the first thing we do is import pygame. The
method init (short for initialize) is then run to get pygame set up and ready to use. We then assign a

variable called screen using the line

which creates a new window that’s 200 by 200 pixels. We then fill it with white (the color 255, 255,
255) on the next line before setting a caption for the window of “Hello Pygame.”
Games use graphics, which usually means using images. In this example, we read an image file into

pygame:

In this case, the image is a file called raspberry.jpg, which is included along with all the other
programs in this book in the programs download section on the book’s website. The call to convert(
) at the end of the line is important because it converts the image into an efficient internal
representation that enables it to be drawn very quickly, which is vital when we start to make the image
move around the window.
Next, we draw the raspberry image on the screen at coordinates 100, 100 using the blit command.
As with the Tkinter canvas you met in the previous chapter, the coordinates start with 0, 0 in the top-

left corner of the screen.
Finally, the last command tells pygame to update the display so that we get to see the image.