Tutorials and guides for programming and using command-line tools abound for Linux. Graphics programming, however, is rarely even touched upon. Although drawing graphics is indeed more tedious than printing text on a terminal, and some knowledge of mathematics is usually required, graphics programming is not terribly difficult. In this article, I will demonstrate how to write a functional, usable program to draw an analog clock face to an image file. By the end of this article, you will have a Python program that generates a stylish analog clock depicting the current time (Figure 1).

Figure 1: The results of the completed clock program.

For this article, I will use the Cairo [1] graphics library to draw the images. Cairo might not be the most intuitive graphics library at first, but it is ubiquitous: Once you know how to use it, you can quickly adapt to drawing with other libraries, such as the GTK [2] graphical user interface toolkit, which also uses Cairo.

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